Hindawi Publishing CorporationISRN VirologyVolume 2013 Article ID 898730 33 pageshttpdxdoiorg1054022013898730

Review ArticleParvovirus B19 Achievements and Challenges

Giorgio Gallinella

Department of Pharmacy and Biotechnology University of Bologna and Microbiology SOrsola-Malpighi HospitalVia Massarenti 9 40138 Bologna Italy

Correspondence should be addressed to Giorgio Gallinella giorgiogallinellauniboit

Received 3 March 2013 Accepted 29 March 2013

Academic Editors C-T Bock M Magnani M Michaelis and V Yedavalli

Copyright copy 2013 Giorgio Gallinella This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Parvovirus B19 is a widespread human pathogenic virus member of the Erythrovirus genus in the Parvoviridae family Infection canbe associated with an ample range of pathologies and clinical manifestations whose characteristics and outcomes depend on theinterplay between the pathogenetic potential of the virus its adaptation to different cellular environments and the physiological andimmune status of the infected individuals The scope of this review is the advances in knowledge on the biological characteristicsof the virus and of virus-host relationships in particular the interactions of the virus with different cellular environments in termsof tropism and ability to achieve a productive replicative cycle or on the contrary to establish persistence the consequences ofinfection in terms of interference with the cell physiology the process of recognition of the virus by the innate or adaptive immunesystem hence the role of the immune system in controlling the infection or in the development of clinical manifestations Linkedto these issues is the continuous effort to develop better diagnostic algorithms and methods and the need for development ofprophylactic and therapeutic options for B19V infections

1 Introduction

Human parvovirus B19 (B19V) is a human pathogenic virusmember of the Erythrovirus genus in the Parvoviridae familyStructural features of parvovirus B19 are common to virusesin the family and include a genome constituted by amoleculeof linear single-stranded DNA of either positive or negativepolarity about 5600 bases in length encapsidated in isomet-ric virions and approximately 25 nm in diameter Infectionis widespread and can be associated with an ample rangeof pathologies and clinical manifestations whose character-istics and outcomes depend on the interplay between thepathogenetic potential of the virus its adaptation to differentcellular environments and the physiological and immunestatus of the infected individuals

The virus shows a marked tropism for erythroid progen-itor cells in the bone marrow exerting a cytotoxic effect andcausing a block in erythropoiesis that can be manifested as atransient or persistent erythroid aplasia However the virushas the capability to infect several different cellular typesas inferred from the detection of viral nucleic acids and

sometimes viral proteins in diverse tissues and the patho-genetic potential of the virus is ample The most commonclinical manifestations of infection are erythema infectiosummainly in children or postinfection arthropathies mainlyaffecting adults however the virus has been implicated ina growing spectrum of other different pathologies amongthem myocarditis and rheumatic diseases Of relevancethe virus can be transmitted to the fetus with possibleconsequences such as fetal death andor hydrops fetalis

The relevant issues in research on B19V and the scopeof this review concern the definition of its biological char-acteristics and of virus-host relationships in particular theinteractions of the virus with different cellular environmentsin terms of tropism and ability to achieve a productivereplicative cycle or on the contrary to establish persistencethe consequences of infection in terms of interference withthe cell physiology the process of recognition of the virusby the innate or adaptive immune system hence the roleof the immune system in controlling the infection or inthe development of clinical manifestations Linked to theseissues are the continuous effort to develop better diagnostic

2 ISRN Virology

algorithms and methods and the need for development ofprophylactic and therapeutic options for B19V infections

2 The Virus

21 Taxonomy The family Parvoviridae includes viruses witha single-stranded linear DNA genome and an icosahedralcapsid 20ndash25 nm in diameter composed of 60 proteinsubunits in a 119879 = 1 arrangement Within the familythe subfamily Parvovirinae includes viruses able to infectvertebrate hosts within the subfamily the genus Erythrovirusincludes the human parvovirus B19 (synonym B19 virusaccepted acronym B19V) as the type species [1]

Once subdivided broadly in parvoviruses able to achieveautonomous replication and helper-dependent parvovirusesthe taxonomy in the Parvoviridae family has grown incomplexity to accommodate the still-increasing number ofrecognized viruses In recent years the introduction ofmolecular screening techniques has allowed the identificationand subsequent characterization of parvoviruses with geneticorganization or sequence divergence high enough to proposea new taxonomic and phylogenetic scheme Within viralspecies a subdivision in genotypes has been introduced inmany instances to accommodate a broad and unexpectedgenetic diversity In the case of B19V three different genotypesare now recognized as distinct evolutionary lineages whilefurther distinctions in subtypes are continuously proposedmainly on epidemiological basis

22 The Genome Initial molecular studies on the genomeof viruses that appeared ldquoparvovirus-likerdquo at the electronmicroscopic observation [2] confirmed the presence of asingle-stranded linear genome of either positive or neg-ative polarity that enabled the classification within theParvoviridae family [3 4] Subsequentmolecular cloning andsequencing [5ndash7] led to a first characterization of the genomestructure and organization and opened the way to the studyof the biological properties of the first human parvovirus ofrecognized clinical relevance

Structural features of B19V genome are common toviruses in the family Linear single-stranded DNA moleculesof either positive or negative polarity 5596 bases in lengthand are encapsidated in isometric virionsMolecules of eitherpolarity are encapsidated at the same frequency and cananneal in solution forming linear double-stranded DNAmoleculesThe viral genome is composed of a unique internalregion containing all the coding sequences flanked by tworepeated inverted terminal regions Terminal regions are383 nt long the distal 365 forming an imperfect palindromeAs a result of the occurrence of sequence asymmetries withinthe palindrome each terminal region can be present in eitherone of the two alternative sequences each is the invertedcomplement of the other (usually referred to as flipflop)Different combinations of these alternative sequences at bothtermini can therefore give rise to four different genomeisomers The presence of self-complementary sequences inthe terminal regions allows for the single-stranded DNAmolecule to adopt terminal loop and stem structures [8]The

presence ofmismatched baseswithin the self-complementaryregions necessarily introduces distortions in such double-stranded structures so that different isomers might differdepending on the distortion introduced Within terminalregions the unique internal region 4830 bases in lengthencompasses all open reading frames coding for viral pro-teins Two major open reading frames are present in theleft half of the genome coding for the viral nonstructuralprotein NS and in the right half of the genome coding for theviral capsid proteins VP1 and VP2 Additional minor readingframes are present in the center and right end of the genomepotentially coding for smaller nonstructural proteins (11 kDa9 kDa 75 kDa) A schematic representation of B19V genomeorganization and functional mapping is reported in Figure 1A more detailed representation of the left terminal region isreported in Figure 2

23 The Virion B19V was first identified tentatively as aparvovirus on the basis of its dimensions and morphologyat the electron microscopy observation Initial biochemicalcharacterization of virions confirmed properties typical ofparvoviruses and a composition of two structural proteinsVP1 andVP2The largerVP1 protein accounts for about 5ofthe virionmass the smaller colinear VP2 protein constitutesthe bulk 95 of the virion [9] Alignment of sequences withincapsid protein genes of viruses in the Parvoviridae familyand comparison with known molecular structures alloweda first structural prediction of the B19V capsid shell [10]Thereafter structural data have been obtained mainly bymeans of cryoelectron microscopy and crystallographic X-ray diffraction studies on VP2-only B19V capsids obtainedas viral-like particles (VLPs) from recombinant systemssuch as baculovirus [11ndash13] More recently native virionseither DNA-containing or empty have been purified andcrystallized and their structure has been compared to thatof VP2-only VLPs [14]

The capsid shell is composed of 60 protein subunits thecore structure is formed by the VP common region formingclassical beta-barrel with eight strands connected by largeloops projecting on the outer surface and determining itstopography and specific structures at the 5- 3- and 2-foldsymmetry axes Similar to other parvoviruses a cylindricalstructure is present at the 5-fold axis forming a gatedchannel connecting interior and outer surface of the virionand whose rim is surrounded by a ldquocanyon-likerdquo depressionwhile typical of B19V is the absence of prominent spikesat the 3-fold axis and a general rounded smooth surfaceWhen comparing VP2VLPs with native virions difference instructures ismainly evident around the 5-fold axis suggestingthat in native virions either DNA-containing or empty thecylindrical channel is normally bordered by the N-termini ofVP2 proteins

Due to the submolar frequency of VP1 its N-terminalsequence (VP1 unique VP1u) has not been determinedby crystallography and the exact atomic structure is stillunknown Two possibilities are still debated It can beexposed at least partially on the outer surface of the virionwhere it may be constantly accessible and recognized by the

ISRN Virology 3

Frame 1Frame 2Frame 3

pAp1 pAp2 pAd

D1 D2 A2-1 A2-2

01

01a

03

02a

02

04

08

06

09

10

03a

05

07

NSVP75 kDa

9 kDa

VP1 VP2

A1-11-2

11 kDa

P6

Figure 1 Schematic representation of B19V genome organization and functionalmapping Top open reading frames identified in the positivestrand of genome arrows indicate the coding regions for viral proteins positioned on theORFmap Center genomeorganization with distinctrepresentation of the terminal and internal regions and indication of the positions of promoter (P6) splice donor (D1 D2) splice acceptor(A1-12 A2-22) and cleavage-polyadenylation (pAp1 pAp2 and pAd) sites Bottom viral mRNAs species black boxes indicate the exoncomposition and light boxes indicate the ORFs contained within mRNAs

100 200 300 400 5001

NSBE 1-4 NSBE 1-4Sp13 Sp13CREBCREB ATF YY1 Sp13 YY1 YY1E2F Oct

CP EBP

CpG dinucleotideTATA box start of transcriptionCis-recognition sequence

Dyad symmetry

Figure 2 Schematic representation of the left terminal region of B19V and distribution of relevant features Thick box left inverted terminalregion and indication of the site of dyad symmetry defining the terminal palindromeThin box contiguous internal unique region Diamondshighlight the distribution of CpG dinucleotides within sequence Box and arrow indicate position of TATA box and start of transcriptionrespectively as part of the P6 promoter Black boxes indicate the position of NS protein-binding elements (NSBE 1-4) and a selection ofcis-recognition sequences for eukaryotic transcription factors as indicated

immune system or as in other viruses in the family it can belocated internal to the capsid proximal to the cylinder at thefivefold axis being exposed at the external surface if virionsare damaged or in the first phase of interaction with targetcells As all other viruses in the family the VP1 unique regionpossesses an intrinsic PLA(2) phospholipase activity neces-sary to maintain viral infectivity [15 16] so its topographicdisposition and dynamic of possible conformational changes

might be crucial for determining a productive interaction ofvirions with target cells

3 Evolution

The genetic diversity of B19V has always been a subject ofinterest as a clue to viral evolution to elucidate possible deter-minants of virus-cell interaction mechanisms and different

4 ISRN Virology

characteristics of virus-host relationships The continuousdevelopment of innovative sequencing techniques has led toa constant growth of sequence data available so it can bepredicted that application of the new generation sequencingtechniqueswill be crucial for a thorough understanding of thedynamics of viral evolution and molecular epidemiology

So far the main achievement was the identification ofthree distinct genotypes of B19V once thought to be a virusspecies with very limited sequence diversity In fact earlysequencing studies reported a uniform picture of sequencevariation within B19V isolates presenting a global degree ofhomology usually higher than 98 and onlyminor variationsin diversity along the different genomic regions [17]This pic-ture changed considerablywith the first identification of someviral isolates that showed a substantial genetic divergence anddistance from previously characterized isolates [18ndash20]

The species B19V is now formally subdivided into threegenotypes the prototype genotype 1 and the two variantgenotypes 2 and 3 isolates belonging to diverse genotypesform clearly separated clusters [21] At the nucleotide levelconsidering alignment of consensus sequences obtained fromavailable complete genomes the genetic distance betweenclusters is about 10 for genotype 1 and 5-6 for genotypes 2and 3 At the same level the genetic distance within clustersis generally lower for genotype 1 normally less than 2 andhigher for genotypes 2 and 3 normally in the range 3ndash10The constant input of new genomic sequences into databasesprompts for further subdivisions into subtypes not formallyrecognized but useful for molecular epidemiological studiesSo within genotype 1 the majority of isolates are referred toas genotype 1a while a few isolates from Asia show separateclustering and are referred to as genotype 1b [22] Withingenotype 3 two distinct subtypes are usually referred to asgenotypes 3a and 3b [23]

All B19V genotypes appear to cocirculate but theirrelative frequency is strikingly different and their spatial andtemporal distribution is not uniform [24ndash28] The prototypegenotype 1a is the major circulating genotype and is presentin all geographic areas [27]The variant genotype 2 is rare butcan be sporadically detected in different geographic settingsincluding Europe [29ndash31] The variant genotype 3 in its twosubtypes can be detected at higher frequency in westernAfrica where it may constitute the prevalent genotype [23]and at lower frequencies in other geographic areas

A different picture emerges when analyzing and typingviral DNA not from blood hence from the viremic phaseof a productive infection but viral DNA normally presentand persistent within tissues as a result of a past infectionthe so-called bioportfolio [32] In these instances the fre-quency of detected viral DNA and the relative abundanceof different genotypes would reflect the spread of virus andits epidemiology in the past These analyses performed indifferent population groups and tissue samples usually ledto the detection of all different genotypes confirming theproperty of B19V to establish a possibly lifelong persistencein tissues Strikingly the frequency of genotype 2 detectedin tissues is normally much higher than what is normallyfound for circulating virus [32ndash34] In a European settingthe frequency of genotype 2 is highest in elder people and

minimal in people born after 1960ndash1970 when genotype 1becomes prevalent therefore suggesting at that date a globalreplacement of genotype 2 with genotype 1 in a patternsimilar to what is described for other animal parvoviruses

The pattern of evolution of B19V and genetic divergenceamong genotypes are still under investigation By inferringthe phylogenetic history and evolutionary dynamics of tem-porally sampled B19V sequences a high rate of evolutionarychange at approximately 10minus4 nucleotide substitutions persite per year was observed [35] This rate is similar tothat of RNA viruses and suggests that high mutation rateshowever characteristic of the Parvoviridae family can leadto a rapid evolutionary dynamics possibly with formation ofviral quasi-speciesThismodel has been further corroboratedby a study that used a large VP sequence data set of plasma-and tissue-derived isolates of B19V to compare the rates ofsequence change in exogenous virus populations with thosepersistently resident in tissues [36] In this model plasma-derived B19V showed a substitution rate of 4 times 10minus4 and anunconstrained (synonymous) substitution rate of 18 times 10minus4per site per year a high mutation frequency that may enablerapid adaptive changes that are more commonly ascribedto RNA virus populations These estimates predict that thelast common ancestor for currently circulating genotype 1variants of B19V existed around 1956 to 1959 fitting well withprevious analyses of the B19V bioportfolio that support acessation of genotype 2 infections and their replacement bygenotype 1 infections in the 1960s In contrast the evolutionof tissue-derived B19V was best modeled when consideringslow or absent sequence change during persistence Hintson a continuous evolutionary process of B19V also comefrommore recentmolecular epidemiological studies utilizinglarge datasets suggesting that even within the more recentgenotype 1a a slow and gradual accumulation of pointmutations can give way to periodical dynamic replacementof strains with higher sequence divergence [37 38]

In conclusion a high rate of nucleotide substitutioncomparable to RNA viruses may lead to the formation ofviral quasi-species and an expansion of the population in thesequence space around master sequences The rapid spreadof infections would then allow for progressive diversificationof viral isolates The observed rate of synonymous versusnonsynonymous substitutions is constantly high thereforeindicating for strong selective pressures on the virus andthis in turn would account for the observed uniformity ofthe biological behavior and immunogenicity of the diversegenotypes [39]

4 Lifestyle

41 Cell Tropism B19V is characterized by a narrow tropismand restricted replicative ability The main target cells areerythroid progenitor cells in the bone marrow that are sus-ceptible and permissive to B19V infection Viremic sera fromthe acute phase of infection cause inhibition of erythropoiesisin culture [40] virus purified from viremic sera specificallyinhibits bone-marrow-derived erythroid progenitor cells ina colony formation assay [41] and is detectable in infectederythroid progenitor cells [42]

ISRN Virology 5

The virus can be propagated to a limited extent insuspension cultures of human erythroid bone marrow cellsstimulated with Epo in culture systems that allow the studyat a molecular level of events associated with the B19V lifecycle [43 44] Enrichment of erythroid progenitor cells frombone marrow can support a higher viral replication [45]Erythroid progenitor cells susceptible to B19V infection canbe also obtained from peripheral blood [46 47] from fetalliver [48ndash50] and from umbilical cord blood [51 52] Morerecently advances in techniques for generating large numbersof human erythroid progenitor cells (EPCs) ex vivo fromcirculating peripheral blood hematopoietic stem cells (HSCs)have been exploited [53 54] In these systems it is possibleto produce pure populations of CD36+ EPCs expanded anddifferentiated from CD34+ HSCs that are highly susceptibleand permissive to B19V These cells represent the best avail-able paradigm to study the events in B19V replicative cycleand their effect on primary target cells

A few continuous cell lines can also support B19V pro-ductive infectionThese cell lines are mainly of myeloblastoidorigin and require Epo both for growth and differentiationand for permissivity to B19VThemegakaryoblastoid cell lineUT7Epo [55] its subcloneUT7EpoS1 and the erythroid cellline Ku812Ep6 [56] are the most widely used However all ofthese systems show limited ability to support viral infectionand low viral yield [57] It should be considered that B19Vis not really adapted to grow in cell cultures and then moststudies on B19V life cycle still rely on infection of primarycells or cell lines with native virus obtained from serum ofinfected patients

A complementary approach to the study of virus-cellinteractions would rely on the generation of completegenomic cloneswith infectious capability as it has been possi-ble for other viruses in the family notably the dependoviruses(adeno-associated viruses AAVs) Inserts comprising theB19V genome excised from plasmid vectors and trans-fected in cells should be able to maintain their functionalcompetence complete a full replicative cycle and generateinfectious viral particles able to start a novel replicative cycleSuch a system might be exploited for performing sequence-structure-function correlation studies and the capabilityto generate recombinant viral particles would foster newresearch activity for example in the field of biotechnologicalapplications

Unfortunately B19V genome has not been easily domes-ticated The first genomic clones obtained possessed eitherincomplete or rearranged terminal regions however didnot show any functional competence following transfection[5 7] AAV-B19V genomic hybrids showed capability togenerate transducing viral particles that may share somebiological properties with B19V [58 59] Finally completeB19V genomic clones were obtained that showed functionalcompetence and the ability to form novel infectious viralparticles [60 61] While extremely useful for the studyof viral expression profile and function of viral proteins[62] these systems still do not lead to a high yield ofinfectious viral particles Further studies and the explo-ration of novel strategies will be required to achieve thisgoal

42 Early Events A main determinant of B19V tropismappears to be its interaction with cellular receptors A firstclue came from the observation of a hemagglutinating activityof B19V [63] similar to other parvoviruses and indicatinga possible specific interaction with carbohydrate moietieson the plasma membrane of cells of erythroid lineage Aspecific receptor for B19V present on the plasma mem-brane of erythroid progenitor cells as well as erythrocyteswas then identified in the glycolipid globoside [64] Glo-boside (Globotetraosylceramide Gb4Cer) is an antigenicdeterminant within the P blood group system for whicha limited degree of polymorphism is also present in thepopulation B19V binds to globoside as measured by thin-layer chromatography Purified globoside blocks the bindingof the virus to erythroid cells and the infectivity of the virusin a hematopoietic colony assay while target cells can beprotected from infection by preincubation with monoclonalantibody to globoside Furthermore erythrocytes lacking Pantigen cannot be hemagglutinated by B19V

The central role of globoside in the infectious process wasunderlined by the demonstration that the rare persons withthe p phenotype lacking globoside on the plasma membraneof erythrocytes and erythroid progenitor cells were naturallyresistant to B19V infection [65] In in vitro infections bonemarrow cells from donors with the p phenotype maintainednormal erythropoiesis despite very high concentrations ofvirus and there was no evidence of infection of erythroidprogenitor cells by B19VThe demonstration of the resistanceof globoside-negative individuals to infection with B19V wasthe first example of resistance to pathogens linked to geneticpolymorphism in the human population This phenomenoncan now be viewed in the context of a complex picture ofcoevolution of human and pathogens where antigenic poly-morphism may constitute a selective advantage especiallywhen considering the selective pressure imposed by othermicrobial parasites for example malaria parasites

The presence of globoside by itself is not sufficientto confer susceptibility to infection [66] Globoside canbe expressed on several cell types mainly primary cellsof erythroid lineage but also other primary cells suchas human umbilical vein endothelial cells (HUVEC) andnormal human lung fibroblasts (NHLF) Several cell linesshow presence of globoside on the plasma membrane Inthese cellular systems globoside can be involved in bindinghowever the level of expression of globoside does not directlycorrelate with the efficiency of viral binding Moreoverdespite the presence of globoside some cell types are resistantto transduction with recombinant B19V vectors

Coreceptors involved in virus binding and internaliza-tion of B19V particles have been identified in the 12057251205731integrins 12057251205731 integrins function as receptors for theextracellular matrix component fibronectin and the ligand-induced activation is involved in numerous cellular functionsincluding anchoring trafficking proliferation and differen-tiationThese integrins are normally expressed on the surfaceof susceptible cells such as erythroid progenitor cells orcan be experimentally induced and confer susceptibility toinfection in other cell lines such as K562 12057251205731 integrincoreceptor function can be enhanced either by stabilizing

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

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different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

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CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

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for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

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juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

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receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

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International Journal of

Volume 2014

Zoology

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Molecular Biology International

GenomicsInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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BioinformaticsAdvances in

Marine BiologyJournal of

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Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

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Stem CellsInternational

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

2 ISRN Virology

algorithms and methods and the need for development ofprophylactic and therapeutic options for B19V infections

2 The Virus

21 Taxonomy The family Parvoviridae includes viruses witha single-stranded linear DNA genome and an icosahedralcapsid 20ndash25 nm in diameter composed of 60 proteinsubunits in a 119879 = 1 arrangement Within the familythe subfamily Parvovirinae includes viruses able to infectvertebrate hosts within the subfamily the genus Erythrovirusincludes the human parvovirus B19 (synonym B19 virusaccepted acronym B19V) as the type species [1]

Once subdivided broadly in parvoviruses able to achieveautonomous replication and helper-dependent parvovirusesthe taxonomy in the Parvoviridae family has grown incomplexity to accommodate the still-increasing number ofrecognized viruses In recent years the introduction ofmolecular screening techniques has allowed the identificationand subsequent characterization of parvoviruses with geneticorganization or sequence divergence high enough to proposea new taxonomic and phylogenetic scheme Within viralspecies a subdivision in genotypes has been introduced inmany instances to accommodate a broad and unexpectedgenetic diversity In the case of B19V three different genotypesare now recognized as distinct evolutionary lineages whilefurther distinctions in subtypes are continuously proposedmainly on epidemiological basis

22 The Genome Initial molecular studies on the genomeof viruses that appeared ldquoparvovirus-likerdquo at the electronmicroscopic observation [2] confirmed the presence of asingle-stranded linear genome of either positive or neg-ative polarity that enabled the classification within theParvoviridae family [3 4] Subsequentmolecular cloning andsequencing [5ndash7] led to a first characterization of the genomestructure and organization and opened the way to the studyof the biological properties of the first human parvovirus ofrecognized clinical relevance

Structural features of B19V genome are common toviruses in the family Linear single-stranded DNA moleculesof either positive or negative polarity 5596 bases in lengthand are encapsidated in isometric virionsMolecules of eitherpolarity are encapsidated at the same frequency and cananneal in solution forming linear double-stranded DNAmoleculesThe viral genome is composed of a unique internalregion containing all the coding sequences flanked by tworepeated inverted terminal regions Terminal regions are383 nt long the distal 365 forming an imperfect palindromeAs a result of the occurrence of sequence asymmetries withinthe palindrome each terminal region can be present in eitherone of the two alternative sequences each is the invertedcomplement of the other (usually referred to as flipflop)Different combinations of these alternative sequences at bothtermini can therefore give rise to four different genomeisomers The presence of self-complementary sequences inthe terminal regions allows for the single-stranded DNAmolecule to adopt terminal loop and stem structures [8]The

presence ofmismatched baseswithin the self-complementaryregions necessarily introduces distortions in such double-stranded structures so that different isomers might differdepending on the distortion introduced Within terminalregions the unique internal region 4830 bases in lengthencompasses all open reading frames coding for viral pro-teins Two major open reading frames are present in theleft half of the genome coding for the viral nonstructuralprotein NS and in the right half of the genome coding for theviral capsid proteins VP1 and VP2 Additional minor readingframes are present in the center and right end of the genomepotentially coding for smaller nonstructural proteins (11 kDa9 kDa 75 kDa) A schematic representation of B19V genomeorganization and functional mapping is reported in Figure 1A more detailed representation of the left terminal region isreported in Figure 2

23 The Virion B19V was first identified tentatively as aparvovirus on the basis of its dimensions and morphologyat the electron microscopy observation Initial biochemicalcharacterization of virions confirmed properties typical ofparvoviruses and a composition of two structural proteinsVP1 andVP2The largerVP1 protein accounts for about 5ofthe virionmass the smaller colinear VP2 protein constitutesthe bulk 95 of the virion [9] Alignment of sequences withincapsid protein genes of viruses in the Parvoviridae familyand comparison with known molecular structures alloweda first structural prediction of the B19V capsid shell [10]Thereafter structural data have been obtained mainly bymeans of cryoelectron microscopy and crystallographic X-ray diffraction studies on VP2-only B19V capsids obtainedas viral-like particles (VLPs) from recombinant systemssuch as baculovirus [11ndash13] More recently native virionseither DNA-containing or empty have been purified andcrystallized and their structure has been compared to thatof VP2-only VLPs [14]

The capsid shell is composed of 60 protein subunits thecore structure is formed by the VP common region formingclassical beta-barrel with eight strands connected by largeloops projecting on the outer surface and determining itstopography and specific structures at the 5- 3- and 2-foldsymmetry axes Similar to other parvoviruses a cylindricalstructure is present at the 5-fold axis forming a gatedchannel connecting interior and outer surface of the virionand whose rim is surrounded by a ldquocanyon-likerdquo depressionwhile typical of B19V is the absence of prominent spikesat the 3-fold axis and a general rounded smooth surfaceWhen comparing VP2VLPs with native virions difference instructures ismainly evident around the 5-fold axis suggestingthat in native virions either DNA-containing or empty thecylindrical channel is normally bordered by the N-termini ofVP2 proteins

Due to the submolar frequency of VP1 its N-terminalsequence (VP1 unique VP1u) has not been determinedby crystallography and the exact atomic structure is stillunknown Two possibilities are still debated It can beexposed at least partially on the outer surface of the virionwhere it may be constantly accessible and recognized by the

ISRN Virology 3

Frame 1Frame 2Frame 3

pAp1 pAp2 pAd

D1 D2 A2-1 A2-2

01

01a

03

02a

02

04

08

06

09

10

03a

05

07

NSVP75 kDa

9 kDa

VP1 VP2

A1-11-2

11 kDa

P6

Figure 1 Schematic representation of B19V genome organization and functionalmapping Top open reading frames identified in the positivestrand of genome arrows indicate the coding regions for viral proteins positioned on theORFmap Center genomeorganization with distinctrepresentation of the terminal and internal regions and indication of the positions of promoter (P6) splice donor (D1 D2) splice acceptor(A1-12 A2-22) and cleavage-polyadenylation (pAp1 pAp2 and pAd) sites Bottom viral mRNAs species black boxes indicate the exoncomposition and light boxes indicate the ORFs contained within mRNAs

100 200 300 400 5001

NSBE 1-4 NSBE 1-4Sp13 Sp13CREBCREB ATF YY1 Sp13 YY1 YY1E2F Oct

CP EBP

CpG dinucleotideTATA box start of transcriptionCis-recognition sequence

Dyad symmetry

Figure 2 Schematic representation of the left terminal region of B19V and distribution of relevant features Thick box left inverted terminalregion and indication of the site of dyad symmetry defining the terminal palindromeThin box contiguous internal unique region Diamondshighlight the distribution of CpG dinucleotides within sequence Box and arrow indicate position of TATA box and start of transcriptionrespectively as part of the P6 promoter Black boxes indicate the position of NS protein-binding elements (NSBE 1-4) and a selection ofcis-recognition sequences for eukaryotic transcription factors as indicated

immune system or as in other viruses in the family it can belocated internal to the capsid proximal to the cylinder at thefivefold axis being exposed at the external surface if virionsare damaged or in the first phase of interaction with targetcells As all other viruses in the family the VP1 unique regionpossesses an intrinsic PLA(2) phospholipase activity neces-sary to maintain viral infectivity [15 16] so its topographicdisposition and dynamic of possible conformational changes

might be crucial for determining a productive interaction ofvirions with target cells

3 Evolution

The genetic diversity of B19V has always been a subject ofinterest as a clue to viral evolution to elucidate possible deter-minants of virus-cell interaction mechanisms and different

4 ISRN Virology

characteristics of virus-host relationships The continuousdevelopment of innovative sequencing techniques has led toa constant growth of sequence data available so it can bepredicted that application of the new generation sequencingtechniqueswill be crucial for a thorough understanding of thedynamics of viral evolution and molecular epidemiology

So far the main achievement was the identification ofthree distinct genotypes of B19V once thought to be a virusspecies with very limited sequence diversity In fact earlysequencing studies reported a uniform picture of sequencevariation within B19V isolates presenting a global degree ofhomology usually higher than 98 and onlyminor variationsin diversity along the different genomic regions [17]This pic-ture changed considerablywith the first identification of someviral isolates that showed a substantial genetic divergence anddistance from previously characterized isolates [18ndash20]

The species B19V is now formally subdivided into threegenotypes the prototype genotype 1 and the two variantgenotypes 2 and 3 isolates belonging to diverse genotypesform clearly separated clusters [21] At the nucleotide levelconsidering alignment of consensus sequences obtained fromavailable complete genomes the genetic distance betweenclusters is about 10 for genotype 1 and 5-6 for genotypes 2and 3 At the same level the genetic distance within clustersis generally lower for genotype 1 normally less than 2 andhigher for genotypes 2 and 3 normally in the range 3ndash10The constant input of new genomic sequences into databasesprompts for further subdivisions into subtypes not formallyrecognized but useful for molecular epidemiological studiesSo within genotype 1 the majority of isolates are referred toas genotype 1a while a few isolates from Asia show separateclustering and are referred to as genotype 1b [22] Withingenotype 3 two distinct subtypes are usually referred to asgenotypes 3a and 3b [23]

All B19V genotypes appear to cocirculate but theirrelative frequency is strikingly different and their spatial andtemporal distribution is not uniform [24ndash28] The prototypegenotype 1a is the major circulating genotype and is presentin all geographic areas [27]The variant genotype 2 is rare butcan be sporadically detected in different geographic settingsincluding Europe [29ndash31] The variant genotype 3 in its twosubtypes can be detected at higher frequency in westernAfrica where it may constitute the prevalent genotype [23]and at lower frequencies in other geographic areas

A different picture emerges when analyzing and typingviral DNA not from blood hence from the viremic phaseof a productive infection but viral DNA normally presentand persistent within tissues as a result of a past infectionthe so-called bioportfolio [32] In these instances the fre-quency of detected viral DNA and the relative abundanceof different genotypes would reflect the spread of virus andits epidemiology in the past These analyses performed indifferent population groups and tissue samples usually ledto the detection of all different genotypes confirming theproperty of B19V to establish a possibly lifelong persistencein tissues Strikingly the frequency of genotype 2 detectedin tissues is normally much higher than what is normallyfound for circulating virus [32ndash34] In a European settingthe frequency of genotype 2 is highest in elder people and

minimal in people born after 1960ndash1970 when genotype 1becomes prevalent therefore suggesting at that date a globalreplacement of genotype 2 with genotype 1 in a patternsimilar to what is described for other animal parvoviruses

The pattern of evolution of B19V and genetic divergenceamong genotypes are still under investigation By inferringthe phylogenetic history and evolutionary dynamics of tem-porally sampled B19V sequences a high rate of evolutionarychange at approximately 10minus4 nucleotide substitutions persite per year was observed [35] This rate is similar tothat of RNA viruses and suggests that high mutation rateshowever characteristic of the Parvoviridae family can leadto a rapid evolutionary dynamics possibly with formation ofviral quasi-speciesThismodel has been further corroboratedby a study that used a large VP sequence data set of plasma-and tissue-derived isolates of B19V to compare the rates ofsequence change in exogenous virus populations with thosepersistently resident in tissues [36] In this model plasma-derived B19V showed a substitution rate of 4 times 10minus4 and anunconstrained (synonymous) substitution rate of 18 times 10minus4per site per year a high mutation frequency that may enablerapid adaptive changes that are more commonly ascribedto RNA virus populations These estimates predict that thelast common ancestor for currently circulating genotype 1variants of B19V existed around 1956 to 1959 fitting well withprevious analyses of the B19V bioportfolio that support acessation of genotype 2 infections and their replacement bygenotype 1 infections in the 1960s In contrast the evolutionof tissue-derived B19V was best modeled when consideringslow or absent sequence change during persistence Hintson a continuous evolutionary process of B19V also comefrommore recentmolecular epidemiological studies utilizinglarge datasets suggesting that even within the more recentgenotype 1a a slow and gradual accumulation of pointmutations can give way to periodical dynamic replacementof strains with higher sequence divergence [37 38]

In conclusion a high rate of nucleotide substitutioncomparable to RNA viruses may lead to the formation ofviral quasi-species and an expansion of the population in thesequence space around master sequences The rapid spreadof infections would then allow for progressive diversificationof viral isolates The observed rate of synonymous versusnonsynonymous substitutions is constantly high thereforeindicating for strong selective pressures on the virus andthis in turn would account for the observed uniformity ofthe biological behavior and immunogenicity of the diversegenotypes [39]

4 Lifestyle

41 Cell Tropism B19V is characterized by a narrow tropismand restricted replicative ability The main target cells areerythroid progenitor cells in the bone marrow that are sus-ceptible and permissive to B19V infection Viremic sera fromthe acute phase of infection cause inhibition of erythropoiesisin culture [40] virus purified from viremic sera specificallyinhibits bone-marrow-derived erythroid progenitor cells ina colony formation assay [41] and is detectable in infectederythroid progenitor cells [42]

ISRN Virology 5

The virus can be propagated to a limited extent insuspension cultures of human erythroid bone marrow cellsstimulated with Epo in culture systems that allow the studyat a molecular level of events associated with the B19V lifecycle [43 44] Enrichment of erythroid progenitor cells frombone marrow can support a higher viral replication [45]Erythroid progenitor cells susceptible to B19V infection canbe also obtained from peripheral blood [46 47] from fetalliver [48ndash50] and from umbilical cord blood [51 52] Morerecently advances in techniques for generating large numbersof human erythroid progenitor cells (EPCs) ex vivo fromcirculating peripheral blood hematopoietic stem cells (HSCs)have been exploited [53 54] In these systems it is possibleto produce pure populations of CD36+ EPCs expanded anddifferentiated from CD34+ HSCs that are highly susceptibleand permissive to B19V These cells represent the best avail-able paradigm to study the events in B19V replicative cycleand their effect on primary target cells

A few continuous cell lines can also support B19V pro-ductive infectionThese cell lines are mainly of myeloblastoidorigin and require Epo both for growth and differentiationand for permissivity to B19VThemegakaryoblastoid cell lineUT7Epo [55] its subcloneUT7EpoS1 and the erythroid cellline Ku812Ep6 [56] are the most widely used However all ofthese systems show limited ability to support viral infectionand low viral yield [57] It should be considered that B19Vis not really adapted to grow in cell cultures and then moststudies on B19V life cycle still rely on infection of primarycells or cell lines with native virus obtained from serum ofinfected patients

A complementary approach to the study of virus-cellinteractions would rely on the generation of completegenomic cloneswith infectious capability as it has been possi-ble for other viruses in the family notably the dependoviruses(adeno-associated viruses AAVs) Inserts comprising theB19V genome excised from plasmid vectors and trans-fected in cells should be able to maintain their functionalcompetence complete a full replicative cycle and generateinfectious viral particles able to start a novel replicative cycleSuch a system might be exploited for performing sequence-structure-function correlation studies and the capabilityto generate recombinant viral particles would foster newresearch activity for example in the field of biotechnologicalapplications

Unfortunately B19V genome has not been easily domes-ticated The first genomic clones obtained possessed eitherincomplete or rearranged terminal regions however didnot show any functional competence following transfection[5 7] AAV-B19V genomic hybrids showed capability togenerate transducing viral particles that may share somebiological properties with B19V [58 59] Finally completeB19V genomic clones were obtained that showed functionalcompetence and the ability to form novel infectious viralparticles [60 61] While extremely useful for the studyof viral expression profile and function of viral proteins[62] these systems still do not lead to a high yield ofinfectious viral particles Further studies and the explo-ration of novel strategies will be required to achieve thisgoal

42 Early Events A main determinant of B19V tropismappears to be its interaction with cellular receptors A firstclue came from the observation of a hemagglutinating activityof B19V [63] similar to other parvoviruses and indicatinga possible specific interaction with carbohydrate moietieson the plasma membrane of cells of erythroid lineage Aspecific receptor for B19V present on the plasma mem-brane of erythroid progenitor cells as well as erythrocyteswas then identified in the glycolipid globoside [64] Glo-boside (Globotetraosylceramide Gb4Cer) is an antigenicdeterminant within the P blood group system for whicha limited degree of polymorphism is also present in thepopulation B19V binds to globoside as measured by thin-layer chromatography Purified globoside blocks the bindingof the virus to erythroid cells and the infectivity of the virusin a hematopoietic colony assay while target cells can beprotected from infection by preincubation with monoclonalantibody to globoside Furthermore erythrocytes lacking Pantigen cannot be hemagglutinated by B19V

The central role of globoside in the infectious process wasunderlined by the demonstration that the rare persons withthe p phenotype lacking globoside on the plasma membraneof erythrocytes and erythroid progenitor cells were naturallyresistant to B19V infection [65] In in vitro infections bonemarrow cells from donors with the p phenotype maintainednormal erythropoiesis despite very high concentrations ofvirus and there was no evidence of infection of erythroidprogenitor cells by B19VThe demonstration of the resistanceof globoside-negative individuals to infection with B19V wasthe first example of resistance to pathogens linked to geneticpolymorphism in the human population This phenomenoncan now be viewed in the context of a complex picture ofcoevolution of human and pathogens where antigenic poly-morphism may constitute a selective advantage especiallywhen considering the selective pressure imposed by othermicrobial parasites for example malaria parasites

The presence of globoside by itself is not sufficientto confer susceptibility to infection [66] Globoside canbe expressed on several cell types mainly primary cellsof erythroid lineage but also other primary cells suchas human umbilical vein endothelial cells (HUVEC) andnormal human lung fibroblasts (NHLF) Several cell linesshow presence of globoside on the plasma membrane Inthese cellular systems globoside can be involved in bindinghowever the level of expression of globoside does not directlycorrelate with the efficiency of viral binding Moreoverdespite the presence of globoside some cell types are resistantto transduction with recombinant B19V vectors

Coreceptors involved in virus binding and internaliza-tion of B19V particles have been identified in the 12057251205731integrins 12057251205731 integrins function as receptors for theextracellular matrix component fibronectin and the ligand-induced activation is involved in numerous cellular functionsincluding anchoring trafficking proliferation and differen-tiationThese integrins are normally expressed on the surfaceof susceptible cells such as erythroid progenitor cells orcan be experimentally induced and confer susceptibility toinfection in other cell lines such as K562 12057251205731 integrincoreceptor function can be enhanced either by stabilizing

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 3

Frame 1Frame 2Frame 3

pAp1 pAp2 pAd

D1 D2 A2-1 A2-2

01

01a

03

02a

02

04

08

06

09

10

03a

05

07

NSVP75 kDa

9 kDa

VP1 VP2

A1-11-2

11 kDa

P6

Figure 1 Schematic representation of B19V genome organization and functionalmapping Top open reading frames identified in the positivestrand of genome arrows indicate the coding regions for viral proteins positioned on theORFmap Center genomeorganization with distinctrepresentation of the terminal and internal regions and indication of the positions of promoter (P6) splice donor (D1 D2) splice acceptor(A1-12 A2-22) and cleavage-polyadenylation (pAp1 pAp2 and pAd) sites Bottom viral mRNAs species black boxes indicate the exoncomposition and light boxes indicate the ORFs contained within mRNAs

100 200 300 400 5001

NSBE 1-4 NSBE 1-4Sp13 Sp13CREBCREB ATF YY1 Sp13 YY1 YY1E2F Oct

CP EBP

CpG dinucleotideTATA box start of transcriptionCis-recognition sequence

Dyad symmetry

Figure 2 Schematic representation of the left terminal region of B19V and distribution of relevant features Thick box left inverted terminalregion and indication of the site of dyad symmetry defining the terminal palindromeThin box contiguous internal unique region Diamondshighlight the distribution of CpG dinucleotides within sequence Box and arrow indicate position of TATA box and start of transcriptionrespectively as part of the P6 promoter Black boxes indicate the position of NS protein-binding elements (NSBE 1-4) and a selection ofcis-recognition sequences for eukaryotic transcription factors as indicated

immune system or as in other viruses in the family it can belocated internal to the capsid proximal to the cylinder at thefivefold axis being exposed at the external surface if virionsare damaged or in the first phase of interaction with targetcells As all other viruses in the family the VP1 unique regionpossesses an intrinsic PLA(2) phospholipase activity neces-sary to maintain viral infectivity [15 16] so its topographicdisposition and dynamic of possible conformational changes

might be crucial for determining a productive interaction ofvirions with target cells

3 Evolution

The genetic diversity of B19V has always been a subject ofinterest as a clue to viral evolution to elucidate possible deter-minants of virus-cell interaction mechanisms and different

4 ISRN Virology

characteristics of virus-host relationships The continuousdevelopment of innovative sequencing techniques has led toa constant growth of sequence data available so it can bepredicted that application of the new generation sequencingtechniqueswill be crucial for a thorough understanding of thedynamics of viral evolution and molecular epidemiology

So far the main achievement was the identification ofthree distinct genotypes of B19V once thought to be a virusspecies with very limited sequence diversity In fact earlysequencing studies reported a uniform picture of sequencevariation within B19V isolates presenting a global degree ofhomology usually higher than 98 and onlyminor variationsin diversity along the different genomic regions [17]This pic-ture changed considerablywith the first identification of someviral isolates that showed a substantial genetic divergence anddistance from previously characterized isolates [18ndash20]

The species B19V is now formally subdivided into threegenotypes the prototype genotype 1 and the two variantgenotypes 2 and 3 isolates belonging to diverse genotypesform clearly separated clusters [21] At the nucleotide levelconsidering alignment of consensus sequences obtained fromavailable complete genomes the genetic distance betweenclusters is about 10 for genotype 1 and 5-6 for genotypes 2and 3 At the same level the genetic distance within clustersis generally lower for genotype 1 normally less than 2 andhigher for genotypes 2 and 3 normally in the range 3ndash10The constant input of new genomic sequences into databasesprompts for further subdivisions into subtypes not formallyrecognized but useful for molecular epidemiological studiesSo within genotype 1 the majority of isolates are referred toas genotype 1a while a few isolates from Asia show separateclustering and are referred to as genotype 1b [22] Withingenotype 3 two distinct subtypes are usually referred to asgenotypes 3a and 3b [23]

All B19V genotypes appear to cocirculate but theirrelative frequency is strikingly different and their spatial andtemporal distribution is not uniform [24ndash28] The prototypegenotype 1a is the major circulating genotype and is presentin all geographic areas [27]The variant genotype 2 is rare butcan be sporadically detected in different geographic settingsincluding Europe [29ndash31] The variant genotype 3 in its twosubtypes can be detected at higher frequency in westernAfrica where it may constitute the prevalent genotype [23]and at lower frequencies in other geographic areas

A different picture emerges when analyzing and typingviral DNA not from blood hence from the viremic phaseof a productive infection but viral DNA normally presentand persistent within tissues as a result of a past infectionthe so-called bioportfolio [32] In these instances the fre-quency of detected viral DNA and the relative abundanceof different genotypes would reflect the spread of virus andits epidemiology in the past These analyses performed indifferent population groups and tissue samples usually ledto the detection of all different genotypes confirming theproperty of B19V to establish a possibly lifelong persistencein tissues Strikingly the frequency of genotype 2 detectedin tissues is normally much higher than what is normallyfound for circulating virus [32ndash34] In a European settingthe frequency of genotype 2 is highest in elder people and

minimal in people born after 1960ndash1970 when genotype 1becomes prevalent therefore suggesting at that date a globalreplacement of genotype 2 with genotype 1 in a patternsimilar to what is described for other animal parvoviruses

The pattern of evolution of B19V and genetic divergenceamong genotypes are still under investigation By inferringthe phylogenetic history and evolutionary dynamics of tem-porally sampled B19V sequences a high rate of evolutionarychange at approximately 10minus4 nucleotide substitutions persite per year was observed [35] This rate is similar tothat of RNA viruses and suggests that high mutation rateshowever characteristic of the Parvoviridae family can leadto a rapid evolutionary dynamics possibly with formation ofviral quasi-speciesThismodel has been further corroboratedby a study that used a large VP sequence data set of plasma-and tissue-derived isolates of B19V to compare the rates ofsequence change in exogenous virus populations with thosepersistently resident in tissues [36] In this model plasma-derived B19V showed a substitution rate of 4 times 10minus4 and anunconstrained (synonymous) substitution rate of 18 times 10minus4per site per year a high mutation frequency that may enablerapid adaptive changes that are more commonly ascribedto RNA virus populations These estimates predict that thelast common ancestor for currently circulating genotype 1variants of B19V existed around 1956 to 1959 fitting well withprevious analyses of the B19V bioportfolio that support acessation of genotype 2 infections and their replacement bygenotype 1 infections in the 1960s In contrast the evolutionof tissue-derived B19V was best modeled when consideringslow or absent sequence change during persistence Hintson a continuous evolutionary process of B19V also comefrommore recentmolecular epidemiological studies utilizinglarge datasets suggesting that even within the more recentgenotype 1a a slow and gradual accumulation of pointmutations can give way to periodical dynamic replacementof strains with higher sequence divergence [37 38]

In conclusion a high rate of nucleotide substitutioncomparable to RNA viruses may lead to the formation ofviral quasi-species and an expansion of the population in thesequence space around master sequences The rapid spreadof infections would then allow for progressive diversificationof viral isolates The observed rate of synonymous versusnonsynonymous substitutions is constantly high thereforeindicating for strong selective pressures on the virus andthis in turn would account for the observed uniformity ofthe biological behavior and immunogenicity of the diversegenotypes [39]

4 Lifestyle

41 Cell Tropism B19V is characterized by a narrow tropismand restricted replicative ability The main target cells areerythroid progenitor cells in the bone marrow that are sus-ceptible and permissive to B19V infection Viremic sera fromthe acute phase of infection cause inhibition of erythropoiesisin culture [40] virus purified from viremic sera specificallyinhibits bone-marrow-derived erythroid progenitor cells ina colony formation assay [41] and is detectable in infectederythroid progenitor cells [42]

ISRN Virology 5

The virus can be propagated to a limited extent insuspension cultures of human erythroid bone marrow cellsstimulated with Epo in culture systems that allow the studyat a molecular level of events associated with the B19V lifecycle [43 44] Enrichment of erythroid progenitor cells frombone marrow can support a higher viral replication [45]Erythroid progenitor cells susceptible to B19V infection canbe also obtained from peripheral blood [46 47] from fetalliver [48ndash50] and from umbilical cord blood [51 52] Morerecently advances in techniques for generating large numbersof human erythroid progenitor cells (EPCs) ex vivo fromcirculating peripheral blood hematopoietic stem cells (HSCs)have been exploited [53 54] In these systems it is possibleto produce pure populations of CD36+ EPCs expanded anddifferentiated from CD34+ HSCs that are highly susceptibleand permissive to B19V These cells represent the best avail-able paradigm to study the events in B19V replicative cycleand their effect on primary target cells

A few continuous cell lines can also support B19V pro-ductive infectionThese cell lines are mainly of myeloblastoidorigin and require Epo both for growth and differentiationand for permissivity to B19VThemegakaryoblastoid cell lineUT7Epo [55] its subcloneUT7EpoS1 and the erythroid cellline Ku812Ep6 [56] are the most widely used However all ofthese systems show limited ability to support viral infectionand low viral yield [57] It should be considered that B19Vis not really adapted to grow in cell cultures and then moststudies on B19V life cycle still rely on infection of primarycells or cell lines with native virus obtained from serum ofinfected patients

A complementary approach to the study of virus-cellinteractions would rely on the generation of completegenomic cloneswith infectious capability as it has been possi-ble for other viruses in the family notably the dependoviruses(adeno-associated viruses AAVs) Inserts comprising theB19V genome excised from plasmid vectors and trans-fected in cells should be able to maintain their functionalcompetence complete a full replicative cycle and generateinfectious viral particles able to start a novel replicative cycleSuch a system might be exploited for performing sequence-structure-function correlation studies and the capabilityto generate recombinant viral particles would foster newresearch activity for example in the field of biotechnologicalapplications

Unfortunately B19V genome has not been easily domes-ticated The first genomic clones obtained possessed eitherincomplete or rearranged terminal regions however didnot show any functional competence following transfection[5 7] AAV-B19V genomic hybrids showed capability togenerate transducing viral particles that may share somebiological properties with B19V [58 59] Finally completeB19V genomic clones were obtained that showed functionalcompetence and the ability to form novel infectious viralparticles [60 61] While extremely useful for the studyof viral expression profile and function of viral proteins[62] these systems still do not lead to a high yield ofinfectious viral particles Further studies and the explo-ration of novel strategies will be required to achieve thisgoal

42 Early Events A main determinant of B19V tropismappears to be its interaction with cellular receptors A firstclue came from the observation of a hemagglutinating activityof B19V [63] similar to other parvoviruses and indicatinga possible specific interaction with carbohydrate moietieson the plasma membrane of cells of erythroid lineage Aspecific receptor for B19V present on the plasma mem-brane of erythroid progenitor cells as well as erythrocyteswas then identified in the glycolipid globoside [64] Glo-boside (Globotetraosylceramide Gb4Cer) is an antigenicdeterminant within the P blood group system for whicha limited degree of polymorphism is also present in thepopulation B19V binds to globoside as measured by thin-layer chromatography Purified globoside blocks the bindingof the virus to erythroid cells and the infectivity of the virusin a hematopoietic colony assay while target cells can beprotected from infection by preincubation with monoclonalantibody to globoside Furthermore erythrocytes lacking Pantigen cannot be hemagglutinated by B19V

The central role of globoside in the infectious process wasunderlined by the demonstration that the rare persons withthe p phenotype lacking globoside on the plasma membraneof erythrocytes and erythroid progenitor cells were naturallyresistant to B19V infection [65] In in vitro infections bonemarrow cells from donors with the p phenotype maintainednormal erythropoiesis despite very high concentrations ofvirus and there was no evidence of infection of erythroidprogenitor cells by B19VThe demonstration of the resistanceof globoside-negative individuals to infection with B19V wasthe first example of resistance to pathogens linked to geneticpolymorphism in the human population This phenomenoncan now be viewed in the context of a complex picture ofcoevolution of human and pathogens where antigenic poly-morphism may constitute a selective advantage especiallywhen considering the selective pressure imposed by othermicrobial parasites for example malaria parasites

The presence of globoside by itself is not sufficientto confer susceptibility to infection [66] Globoside canbe expressed on several cell types mainly primary cellsof erythroid lineage but also other primary cells suchas human umbilical vein endothelial cells (HUVEC) andnormal human lung fibroblasts (NHLF) Several cell linesshow presence of globoside on the plasma membrane Inthese cellular systems globoside can be involved in bindinghowever the level of expression of globoside does not directlycorrelate with the efficiency of viral binding Moreoverdespite the presence of globoside some cell types are resistantto transduction with recombinant B19V vectors

Coreceptors involved in virus binding and internaliza-tion of B19V particles have been identified in the 12057251205731integrins 12057251205731 integrins function as receptors for theextracellular matrix component fibronectin and the ligand-induced activation is involved in numerous cellular functionsincluding anchoring trafficking proliferation and differen-tiationThese integrins are normally expressed on the surfaceof susceptible cells such as erythroid progenitor cells orcan be experimentally induced and confer susceptibility toinfection in other cell lines such as K562 12057251205731 integrincoreceptor function can be enhanced either by stabilizing

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

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macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

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Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

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Stem CellsInternational

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

4 ISRN Virology

characteristics of virus-host relationships The continuousdevelopment of innovative sequencing techniques has led toa constant growth of sequence data available so it can bepredicted that application of the new generation sequencingtechniqueswill be crucial for a thorough understanding of thedynamics of viral evolution and molecular epidemiology

So far the main achievement was the identification ofthree distinct genotypes of B19V once thought to be a virusspecies with very limited sequence diversity In fact earlysequencing studies reported a uniform picture of sequencevariation within B19V isolates presenting a global degree ofhomology usually higher than 98 and onlyminor variationsin diversity along the different genomic regions [17]This pic-ture changed considerablywith the first identification of someviral isolates that showed a substantial genetic divergence anddistance from previously characterized isolates [18ndash20]

The species B19V is now formally subdivided into threegenotypes the prototype genotype 1 and the two variantgenotypes 2 and 3 isolates belonging to diverse genotypesform clearly separated clusters [21] At the nucleotide levelconsidering alignment of consensus sequences obtained fromavailable complete genomes the genetic distance betweenclusters is about 10 for genotype 1 and 5-6 for genotypes 2and 3 At the same level the genetic distance within clustersis generally lower for genotype 1 normally less than 2 andhigher for genotypes 2 and 3 normally in the range 3ndash10The constant input of new genomic sequences into databasesprompts for further subdivisions into subtypes not formallyrecognized but useful for molecular epidemiological studiesSo within genotype 1 the majority of isolates are referred toas genotype 1a while a few isolates from Asia show separateclustering and are referred to as genotype 1b [22] Withingenotype 3 two distinct subtypes are usually referred to asgenotypes 3a and 3b [23]

All B19V genotypes appear to cocirculate but theirrelative frequency is strikingly different and their spatial andtemporal distribution is not uniform [24ndash28] The prototypegenotype 1a is the major circulating genotype and is presentin all geographic areas [27]The variant genotype 2 is rare butcan be sporadically detected in different geographic settingsincluding Europe [29ndash31] The variant genotype 3 in its twosubtypes can be detected at higher frequency in westernAfrica where it may constitute the prevalent genotype [23]and at lower frequencies in other geographic areas

A different picture emerges when analyzing and typingviral DNA not from blood hence from the viremic phaseof a productive infection but viral DNA normally presentand persistent within tissues as a result of a past infectionthe so-called bioportfolio [32] In these instances the fre-quency of detected viral DNA and the relative abundanceof different genotypes would reflect the spread of virus andits epidemiology in the past These analyses performed indifferent population groups and tissue samples usually ledto the detection of all different genotypes confirming theproperty of B19V to establish a possibly lifelong persistencein tissues Strikingly the frequency of genotype 2 detectedin tissues is normally much higher than what is normallyfound for circulating virus [32ndash34] In a European settingthe frequency of genotype 2 is highest in elder people and

minimal in people born after 1960ndash1970 when genotype 1becomes prevalent therefore suggesting at that date a globalreplacement of genotype 2 with genotype 1 in a patternsimilar to what is described for other animal parvoviruses

The pattern of evolution of B19V and genetic divergenceamong genotypes are still under investigation By inferringthe phylogenetic history and evolutionary dynamics of tem-porally sampled B19V sequences a high rate of evolutionarychange at approximately 10minus4 nucleotide substitutions persite per year was observed [35] This rate is similar tothat of RNA viruses and suggests that high mutation rateshowever characteristic of the Parvoviridae family can leadto a rapid evolutionary dynamics possibly with formation ofviral quasi-speciesThismodel has been further corroboratedby a study that used a large VP sequence data set of plasma-and tissue-derived isolates of B19V to compare the rates ofsequence change in exogenous virus populations with thosepersistently resident in tissues [36] In this model plasma-derived B19V showed a substitution rate of 4 times 10minus4 and anunconstrained (synonymous) substitution rate of 18 times 10minus4per site per year a high mutation frequency that may enablerapid adaptive changes that are more commonly ascribedto RNA virus populations These estimates predict that thelast common ancestor for currently circulating genotype 1variants of B19V existed around 1956 to 1959 fitting well withprevious analyses of the B19V bioportfolio that support acessation of genotype 2 infections and their replacement bygenotype 1 infections in the 1960s In contrast the evolutionof tissue-derived B19V was best modeled when consideringslow or absent sequence change during persistence Hintson a continuous evolutionary process of B19V also comefrommore recentmolecular epidemiological studies utilizinglarge datasets suggesting that even within the more recentgenotype 1a a slow and gradual accumulation of pointmutations can give way to periodical dynamic replacementof strains with higher sequence divergence [37 38]

In conclusion a high rate of nucleotide substitutioncomparable to RNA viruses may lead to the formation ofviral quasi-species and an expansion of the population in thesequence space around master sequences The rapid spreadof infections would then allow for progressive diversificationof viral isolates The observed rate of synonymous versusnonsynonymous substitutions is constantly high thereforeindicating for strong selective pressures on the virus andthis in turn would account for the observed uniformity ofthe biological behavior and immunogenicity of the diversegenotypes [39]

4 Lifestyle

41 Cell Tropism B19V is characterized by a narrow tropismand restricted replicative ability The main target cells areerythroid progenitor cells in the bone marrow that are sus-ceptible and permissive to B19V infection Viremic sera fromthe acute phase of infection cause inhibition of erythropoiesisin culture [40] virus purified from viremic sera specificallyinhibits bone-marrow-derived erythroid progenitor cells ina colony formation assay [41] and is detectable in infectederythroid progenitor cells [42]

ISRN Virology 5

The virus can be propagated to a limited extent insuspension cultures of human erythroid bone marrow cellsstimulated with Epo in culture systems that allow the studyat a molecular level of events associated with the B19V lifecycle [43 44] Enrichment of erythroid progenitor cells frombone marrow can support a higher viral replication [45]Erythroid progenitor cells susceptible to B19V infection canbe also obtained from peripheral blood [46 47] from fetalliver [48ndash50] and from umbilical cord blood [51 52] Morerecently advances in techniques for generating large numbersof human erythroid progenitor cells (EPCs) ex vivo fromcirculating peripheral blood hematopoietic stem cells (HSCs)have been exploited [53 54] In these systems it is possibleto produce pure populations of CD36+ EPCs expanded anddifferentiated from CD34+ HSCs that are highly susceptibleand permissive to B19V These cells represent the best avail-able paradigm to study the events in B19V replicative cycleand their effect on primary target cells

A few continuous cell lines can also support B19V pro-ductive infectionThese cell lines are mainly of myeloblastoidorigin and require Epo both for growth and differentiationand for permissivity to B19VThemegakaryoblastoid cell lineUT7Epo [55] its subcloneUT7EpoS1 and the erythroid cellline Ku812Ep6 [56] are the most widely used However all ofthese systems show limited ability to support viral infectionand low viral yield [57] It should be considered that B19Vis not really adapted to grow in cell cultures and then moststudies on B19V life cycle still rely on infection of primarycells or cell lines with native virus obtained from serum ofinfected patients

A complementary approach to the study of virus-cellinteractions would rely on the generation of completegenomic cloneswith infectious capability as it has been possi-ble for other viruses in the family notably the dependoviruses(adeno-associated viruses AAVs) Inserts comprising theB19V genome excised from plasmid vectors and trans-fected in cells should be able to maintain their functionalcompetence complete a full replicative cycle and generateinfectious viral particles able to start a novel replicative cycleSuch a system might be exploited for performing sequence-structure-function correlation studies and the capabilityto generate recombinant viral particles would foster newresearch activity for example in the field of biotechnologicalapplications

Unfortunately B19V genome has not been easily domes-ticated The first genomic clones obtained possessed eitherincomplete or rearranged terminal regions however didnot show any functional competence following transfection[5 7] AAV-B19V genomic hybrids showed capability togenerate transducing viral particles that may share somebiological properties with B19V [58 59] Finally completeB19V genomic clones were obtained that showed functionalcompetence and the ability to form novel infectious viralparticles [60 61] While extremely useful for the studyof viral expression profile and function of viral proteins[62] these systems still do not lead to a high yield ofinfectious viral particles Further studies and the explo-ration of novel strategies will be required to achieve thisgoal

42 Early Events A main determinant of B19V tropismappears to be its interaction with cellular receptors A firstclue came from the observation of a hemagglutinating activityof B19V [63] similar to other parvoviruses and indicatinga possible specific interaction with carbohydrate moietieson the plasma membrane of cells of erythroid lineage Aspecific receptor for B19V present on the plasma mem-brane of erythroid progenitor cells as well as erythrocyteswas then identified in the glycolipid globoside [64] Glo-boside (Globotetraosylceramide Gb4Cer) is an antigenicdeterminant within the P blood group system for whicha limited degree of polymorphism is also present in thepopulation B19V binds to globoside as measured by thin-layer chromatography Purified globoside blocks the bindingof the virus to erythroid cells and the infectivity of the virusin a hematopoietic colony assay while target cells can beprotected from infection by preincubation with monoclonalantibody to globoside Furthermore erythrocytes lacking Pantigen cannot be hemagglutinated by B19V

The central role of globoside in the infectious process wasunderlined by the demonstration that the rare persons withthe p phenotype lacking globoside on the plasma membraneof erythrocytes and erythroid progenitor cells were naturallyresistant to B19V infection [65] In in vitro infections bonemarrow cells from donors with the p phenotype maintainednormal erythropoiesis despite very high concentrations ofvirus and there was no evidence of infection of erythroidprogenitor cells by B19VThe demonstration of the resistanceof globoside-negative individuals to infection with B19V wasthe first example of resistance to pathogens linked to geneticpolymorphism in the human population This phenomenoncan now be viewed in the context of a complex picture ofcoevolution of human and pathogens where antigenic poly-morphism may constitute a selective advantage especiallywhen considering the selective pressure imposed by othermicrobial parasites for example malaria parasites

The presence of globoside by itself is not sufficientto confer susceptibility to infection [66] Globoside canbe expressed on several cell types mainly primary cellsof erythroid lineage but also other primary cells suchas human umbilical vein endothelial cells (HUVEC) andnormal human lung fibroblasts (NHLF) Several cell linesshow presence of globoside on the plasma membrane Inthese cellular systems globoside can be involved in bindinghowever the level of expression of globoside does not directlycorrelate with the efficiency of viral binding Moreoverdespite the presence of globoside some cell types are resistantto transduction with recombinant B19V vectors

Coreceptors involved in virus binding and internaliza-tion of B19V particles have been identified in the 12057251205731integrins 12057251205731 integrins function as receptors for theextracellular matrix component fibronectin and the ligand-induced activation is involved in numerous cellular functionsincluding anchoring trafficking proliferation and differen-tiationThese integrins are normally expressed on the surfaceof susceptible cells such as erythroid progenitor cells orcan be experimentally induced and confer susceptibility toinfection in other cell lines such as K562 12057251205731 integrincoreceptor function can be enhanced either by stabilizing

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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BioinformaticsAdvances in

Marine BiologyJournal of

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Signal TransductionJournal of

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ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 5

The virus can be propagated to a limited extent insuspension cultures of human erythroid bone marrow cellsstimulated with Epo in culture systems that allow the studyat a molecular level of events associated with the B19V lifecycle [43 44] Enrichment of erythroid progenitor cells frombone marrow can support a higher viral replication [45]Erythroid progenitor cells susceptible to B19V infection canbe also obtained from peripheral blood [46 47] from fetalliver [48ndash50] and from umbilical cord blood [51 52] Morerecently advances in techniques for generating large numbersof human erythroid progenitor cells (EPCs) ex vivo fromcirculating peripheral blood hematopoietic stem cells (HSCs)have been exploited [53 54] In these systems it is possibleto produce pure populations of CD36+ EPCs expanded anddifferentiated from CD34+ HSCs that are highly susceptibleand permissive to B19V These cells represent the best avail-able paradigm to study the events in B19V replicative cycleand their effect on primary target cells

A few continuous cell lines can also support B19V pro-ductive infectionThese cell lines are mainly of myeloblastoidorigin and require Epo both for growth and differentiationand for permissivity to B19VThemegakaryoblastoid cell lineUT7Epo [55] its subcloneUT7EpoS1 and the erythroid cellline Ku812Ep6 [56] are the most widely used However all ofthese systems show limited ability to support viral infectionand low viral yield [57] It should be considered that B19Vis not really adapted to grow in cell cultures and then moststudies on B19V life cycle still rely on infection of primarycells or cell lines with native virus obtained from serum ofinfected patients

A complementary approach to the study of virus-cellinteractions would rely on the generation of completegenomic cloneswith infectious capability as it has been possi-ble for other viruses in the family notably the dependoviruses(adeno-associated viruses AAVs) Inserts comprising theB19V genome excised from plasmid vectors and trans-fected in cells should be able to maintain their functionalcompetence complete a full replicative cycle and generateinfectious viral particles able to start a novel replicative cycleSuch a system might be exploited for performing sequence-structure-function correlation studies and the capabilityto generate recombinant viral particles would foster newresearch activity for example in the field of biotechnologicalapplications

Unfortunately B19V genome has not been easily domes-ticated The first genomic clones obtained possessed eitherincomplete or rearranged terminal regions however didnot show any functional competence following transfection[5 7] AAV-B19V genomic hybrids showed capability togenerate transducing viral particles that may share somebiological properties with B19V [58 59] Finally completeB19V genomic clones were obtained that showed functionalcompetence and the ability to form novel infectious viralparticles [60 61] While extremely useful for the studyof viral expression profile and function of viral proteins[62] these systems still do not lead to a high yield ofinfectious viral particles Further studies and the explo-ration of novel strategies will be required to achieve thisgoal

42 Early Events A main determinant of B19V tropismappears to be its interaction with cellular receptors A firstclue came from the observation of a hemagglutinating activityof B19V [63] similar to other parvoviruses and indicatinga possible specific interaction with carbohydrate moietieson the plasma membrane of cells of erythroid lineage Aspecific receptor for B19V present on the plasma mem-brane of erythroid progenitor cells as well as erythrocyteswas then identified in the glycolipid globoside [64] Glo-boside (Globotetraosylceramide Gb4Cer) is an antigenicdeterminant within the P blood group system for whicha limited degree of polymorphism is also present in thepopulation B19V binds to globoside as measured by thin-layer chromatography Purified globoside blocks the bindingof the virus to erythroid cells and the infectivity of the virusin a hematopoietic colony assay while target cells can beprotected from infection by preincubation with monoclonalantibody to globoside Furthermore erythrocytes lacking Pantigen cannot be hemagglutinated by B19V

The central role of globoside in the infectious process wasunderlined by the demonstration that the rare persons withthe p phenotype lacking globoside on the plasma membraneof erythrocytes and erythroid progenitor cells were naturallyresistant to B19V infection [65] In in vitro infections bonemarrow cells from donors with the p phenotype maintainednormal erythropoiesis despite very high concentrations ofvirus and there was no evidence of infection of erythroidprogenitor cells by B19VThe demonstration of the resistanceof globoside-negative individuals to infection with B19V wasthe first example of resistance to pathogens linked to geneticpolymorphism in the human population This phenomenoncan now be viewed in the context of a complex picture ofcoevolution of human and pathogens where antigenic poly-morphism may constitute a selective advantage especiallywhen considering the selective pressure imposed by othermicrobial parasites for example malaria parasites

The presence of globoside by itself is not sufficientto confer susceptibility to infection [66] Globoside canbe expressed on several cell types mainly primary cellsof erythroid lineage but also other primary cells suchas human umbilical vein endothelial cells (HUVEC) andnormal human lung fibroblasts (NHLF) Several cell linesshow presence of globoside on the plasma membrane Inthese cellular systems globoside can be involved in bindinghowever the level of expression of globoside does not directlycorrelate with the efficiency of viral binding Moreoverdespite the presence of globoside some cell types are resistantto transduction with recombinant B19V vectors

Coreceptors involved in virus binding and internaliza-tion of B19V particles have been identified in the 12057251205731integrins 12057251205731 integrins function as receptors for theextracellular matrix component fibronectin and the ligand-induced activation is involved in numerous cellular functionsincluding anchoring trafficking proliferation and differen-tiationThese integrins are normally expressed on the surfaceof susceptible cells such as erythroid progenitor cells orcan be experimentally induced and confer susceptibility toinfection in other cell lines such as K562 12057251205731 integrincoreceptor function can be enhanced either by stabilizing

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

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Nucleic AcidsJournal of

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

6 ISRN Virology

the high-affinity conformation of 1205731 integrins or by inducing1205731 integrin clustering suggesting that 1205731 integrin-mediatedsignaling might be important for B19V internalization [67]Integrin function appears to be regulated in a cell type-specificmanner through coexpressed integrins and preferen-tial B19V entry into erythroid progenitor cells is promoted bya robust 1205731 integrin response that is enhanced through stablepreclustering of coexpressed 1205732 and 1205733 integrins [68] Inprimary human erythroid progenitor cells the cytoskeletonorganization also allows efficient recruitment of 1205731 integrinsby brief pharmacological stimulation of Rap1 GTP loadingsignificantly increasing B19V internalization [69]

Other molecules may be implicated in the attachmentphase of B19V to different cell types In addition to recogniz-ing globoside as themain receptor weak interactions of B19Vhave been shown to occur with other carbohydrate moietiesof several tissue-specific membrane glycosphingolipids thusexpanding the spectrum of possible susceptible cells [70]Although a correlation can be observed between multipleglycosphingolipids expression B19V capsid binding andthe tissue tropism observed clinically in B19 parvovirus-associated diseases a functional role has not been demon-strated in instances other than globoside Finally the DNA-binding protein Ku80 can possibly act as an alternativecoreceptor for B19V [71] Although described as a nuclearprotein Ku80 is present on the cell surface of CD36+ humanbone marrow erythroid cells CD3 T cells and CD20 B cellsthus implicating cells of lymphoid lineage as target cells Thepossible role of Ku80 in the life cycle and pathogenetic poten-tial of B19V needs to be confirmed by further investigation

The interactions of B19V virionswith globoside have beenfurther characterized Visualization of B19V virions com-plexed in solution with globoside identified the receptor con-tact area within a depression on the threefold symmetry axis[72] In a subsequent study [73] neither specific complexesnor specific interaction of B19V with reconstituted plasmamembrane could be detected suggesting the stringency ofa definite conformationdistribution of glycolipids on theplasma membrane for example within lipid rafts and thepresence and a functional role of coreceptors Therefore in amultistep model a first interaction of viral capsids with glo-boside as a docking molecule might be followed by strongerinteractions with integrins followed by internalization of thevirus The absence of integrins for example on erythrocyteplasmamembranewould prevent internalization in a nonper-missive cellular environment while their activation followingcontact with virus would trigger a downstream cascade ofevents allowing infection of nucleated cells This model hasbeen further investigated

As discussed there is uncertainty regarding the topo-graphic disposition of theVP1u region As a possibility theN-terminal portion of the VP1u region might not be accessiblein native capsids however exposure of capsids to increasingtemperatures or low pHmight lead to its progressive accessi-bility to neutralizing antibodies without particle disassemblyThe measurement of the VP1u-associated PLA(2) activityof B19V capsids also suggests that this region is normallyinternal to the capsid shell but becomes exposed in heat-and in low-pH-treated particles [74] Similarly a proportion

of the capsids can externalize the VP1u-PLA(2) motif uponbinding on human red blood cells (RBCs) not causing directhemolysis but inducing an increased osmotic fragility of thecells by a mechanism involving the PLA(2) activity of theexposed VP1u In the acute phase of infection most virionscirculating in the blood can be associated with the RBCfraction not being able to infect susceptible cells but playinga significant pathogenetic role because of the exposure of theimmunodominantVP1u region including its PLA(2) domain[75] On the other hand the early exposure of VP1u mightfacilitate viral internalization andor uncoating in targetcells In UT7Epo cells expression of Gb4Cer and CD49e(integrin 1205725) is high B19V colocalizes with Gb4Cer and toa lesser extent with CD49e but only anti-Gb4Cer antibodiescan compete with virus attachment Normally only a smallproportion of cell-bound viruses can be internalized whilethe majority detaches from the receptor and acquires ahigher cell binding capacity and infectivity This effect hasbeen attributed to conformational changes in the capsidtriggered by attachment of B19V to cells and leading tothe accessibility of the VP1u region The receptor-mediatedexposure of VP1u region is critical for virus internalizationsince capsids lacking VP1 can bind to cells but are notinternalized [76] Then Gb4Cer is not only the primaryreceptor for B19V attachment but also themediator of capsidrearrangements required for the interactions leading to virusinternalization The capacity of the virus to detach fromcells and reattach with higher efficiency would enhance theprobability of productive infections

A first insight into the early steps of B19V infection thepath of virions and mechanisms involved in virus uptaketrafficking and nuclear import has recently been investigatedinUT7Epo cells [77] In these B19V and its receptor Gb4Cerassociate with lipid rafts predominantly of the noncaveolartype B19V is internalized by clathrin-dependent endocyto-sis and spreads rapidly throughout the endocytic pathwayreaching the lysosomal compartment within minutes wherea substantial proportion of virus is degraded Endocytic vesi-cles are not permeabilized by B19V indicating a mechanismof endosomal escape without apparent membrane damageCompounds such as NH

4

Cl which raise endosomal pH canblock the infection by preventing endosomal escape resultingin a massive accumulation of capsids in the lysosomes Intactvirions do not enter the nucleus and the amount of viralDNAin the nuclear compartment is too low to be measured overbackground before the onset of macromolecular synthesisIn contrast in the presence of chloroquine the transferof incoming viruses from late endosomes to lysosomesis prevented the viral DNA is not degraded and evenif capsids remain extranuclear viral DNA is progressivelyand substantially associated with the nucleus The effect ofchloroquine is to boost B19V infection in different cell types[78] and even nonpermissive cells such as HepG2 [79] canbecome permissive in its presence

Novel questions then warrant further investigation suchas the precise role of lipid rafts in the process of virusentry the mechanism by which B19V escapes from endo-somes without detectable permeabilizationdamage and thepathway involved in the nuclear import of viral DNA In

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Volume 2014

Zoology

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Enzyme Research

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International Journal of

Microbiology

ISRN Virology 7

particular the exact role of phospholipase activity in theVP1uregion [80] required for infectivity needs to be elucidated

43 Macromolecular Synthesis Once the viral genome isexposed within the nucleus viral macromolecular synthesismainly relies on the cellular machinery for transcription ofmessengers and replication of the viral genome Typically forthe family Parvoviridae it is assumed that these activitiesdepend on an environment of actively replicating cells andrequire S-phase specific cellular factors However it is nowemerging that B19V by itself has the ability to modulateprogression through the cell cycle to its own advantage

Conversion of the incoming parental single-strandedgenome into a double-stranded genome is the first step anda possible key determinant of the replicative cycle [81] B19Vencapsidates single-stranded genomes of either positive ornegative sense and as inverted terminal repeats are identicalit is assumed that both strands are functionally equiva-lent Terminal regions have an almost perfect palindromicsequence and then possess the ability to fold at a dyad symme-try axis assuming double-stranded terminal hairpin struc-tures that provide the necessary priming structure for cellularDNA polymerases to synthesize the complementary strandAccessibility of these terminal structures and their capabilityto prime synthesis can be regarded as first bottleneck fora productive replicative cycle Permissive or nonpermissivecellular environments and the outcome towards a productiveor nonproductive replicative cycle may depend on the abilityof different cells to support or consent synthesis of thecomplementary strand

Replicative intermediates of B19V have not been thor-oughly characterized ssDNA monomeric dsDNA anddimeric dsDNA forms are all detected in productivelyinfected cells [43 44] The terminal regions act as originsof replication and in a dsDNA form they can be present ineither closed or extended conformations It is assumed that asin other parvoviruses replication proceeds through cycles ofterminal resolution and hairpin-primed strand displacementsynthesis possibly via a rolling hairpin mechanism The cel-lular DNA polymerase activity is involved together with viralNS protein that can bind to cis-recognition elements withinthe terminal regions and is predicted to have endonucleaseand helicase activity necessary for the terminal resolutionprocess and strand-displacement synthesis [82] It is not yetknown what role if any the sequence asymmetries withinthe palindrome may play in directing or regulating themechanistic details of the replication process

Formation of a double-stranded intermediate generates atranscriptional active template A unique promoter is presentand active on the genome mapped within the internalunique region close to the left inverted terminal regionof the genome and usually referred to as P6 directingtranscription from the left to the right end of the genome[83 84]Mapping of regulatory elements within the promotershows the presence of a complex regulatory region containingmultiple sequences which affect promoter strength and thatthe GC-box motif is a major controlling sequence for invitro transcription [85] Moreover the promoter is transac-tivated by the nonstructural protein NS that therefore has a

positive feedback effect on the activity of its own promoter[86]

This P6 promoter is broadly active in many cell typesso tropism is unlikely to be regulated at the level of tran-scriptional initiation although differences can be measuredamong different cell types [87 88] An investigation of thesequence within the promoter region shows the presenceof several cis-recognition elements for transcription factors[89] For some of these there is experimental evidence offunctional involvement YY1 [90] E4TF1 [91] Oct-1 Sp1 andSp3 [92 93] all can bind to elements mapped within thepromoter region The viral NS protein interacts with cellularSp factors and in this way contributes to transactivation of itsown promoter Finally activity of the promoter may also beresponsive to hypoxic environment [94]

Transcription of the viral genome generates an ensembleof mature transcripts due to a combination of co- and post-transcriptional events A complex array of viralmRNAs arisesfrom the presence on the pre-mRNA of two splicing donorsites (D1 and D2) each followed by two alternative spliceacceptor sites (A1-12 and A2-12) and of two transcriptionaltermination sites in the middle and at the right end of thegenome (pAp and pAd) Initial mapping showed that at leastnine classes of viral mRNAs are produced as a result ofthe diverse combinations of possible splicing and cleavageevents [95] All viral transcripts share a common 60 nt longleader sequence at their 51015840 end Then one class of mRNAis not spliced and terminates in the middle of the genomecontaining the left major ORF coding for the NS proteinwhile all other classes undergo single or double splicingterminating either in the middle or at the right end of thegenome in this last case encompassing the right major ORFcoding for viral capsid proteins [96] The complement ofviral mRNAs is redundant with respect to recognized viralORFs and the different viral mRNAs species can be cistronicmonocistronic or possibly bicistronic potentially coding fora rather restricted viral proteome [97]

Precise mapping of splicing junctions and cleavage-polyadenylation sites was first obtained by cloning andsequencing of cDNA libraries obtained from infected ery-throid cells [98] Thereafter the cis-elements directing pro-cessing of precursor mRNA have been actively investigatedin several cellular systems All the spliced B19V mRNAtranscripts contain the 60 nt long 51015840 leader sequence splicedfrom the D1 splice site to the central exon which spansthe A1-1A1-2 to D2 splice site Further splicing at the D2donor site is a central step in the control of B19V pre-mRNA processingThe sequence of the central exon containsseveral exonic splicing enhancersintronic splicing enhancers(ESEsISEs) elements recognized by SR proteins Of theseISE1 and ESE1 elements have been identified within A1-1and A1-2 sites ESE2 and ESE3 within A1-2 and D2 andISE2 downstream of D2 site Overall the definition of theB19V central exon will be the consequence of a balancedrecognition of cis-elements by SR proteins SR proteins thatbind to ESE1 and ESE2 will promote splicing at the A1-1 andA1-2 acceptor sites respectively while SR proteins that bindto ESE3 and ISE2 will facilitate recognition of the D2 donorsiteThe frequency of recognition events can provide the basis

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

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macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

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it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

8 ISRN Virology

for regulatory splicing during B19V pre-mRNA processing[99]

A second key factor in the definition of viralmRNAs is thefrequency of cleavage-polyadenylation events at the centeror right end sites present in the genome In the center ofthe genome two cleavage-polyadenylation sites have beenmapped respectively pAp1 and pAp2 Processing of pre-mRNAs at the pAp1 site is programmed by a nonconsensushexanucleotide core motif (AUUAAA) Efficient use of thiselement requires both downstream and upstream cis-actingelements and is further influenced by a second adjacentnonconsensus motif (AAUAAC) On the contrary pAp2shows a canonic hexanucleotide coremotif (AAUAAA) [100]Cleavage at pAp1 will generate the most abundant classesof viral mRNAs cleavage at pAp2 will occur at tenfoldlower frequency and generate alternative mRNAs potentiallyincluding an additional small ORF for a 9 kDa protein whilereadthrough will generate mRNAs extending into the capsidcoding region and coding for VP1 protein Competitivesplicing from D2 to A2-1 or A2-2 sites will regulate theproduction of mRNAs coding for VP2 or 11 kDa proteinsrespectively [101] All of these events appear to be coordinatedand in relation to the replicative process involving the DNAtemplate In the absence of genome replication internalpolyadenylation of viral mRNAs at pAp sites is favoredwhile replication of the viral genome enhances readthroughof pAp and the polyadenylation of B19 virus transcripts atthe distal site pAd [102 103] Therefore replication of thegenome would facilitate the generation of sufficient full-length transcripts that encode the viral capsid proteins andthe essential 11-kDa nonstructural protein

44 Expression Profile Differences in the expression profileof B19V genomemay occur during the course of a productivereplicative cycle as a result of an ensemble of coordinatedregulatory events or can be distinctive of the restrictionsposed by different cellular environments to a productivereplicative cycle

An early model of B19V genome expression obtained bySouthern and Northern Blot analysis of viral nucleic acidsfrom synchronized infected UT7Epo cells indicated thepresence of early and late events involving genome transcrip-tion and replication [104] In particular RNA transcriptionappeared as an early event following infection with viralRNA detected about 6 hours after infection (hpi) and withan earlier appearance of nonstructural protein RNA (6 hpi)compared to capsid protein RNA (24 hpi) In contrast dimer-replicative intermediate forms of DNA did not appear untilmore than 16 hpi after infectionMore recently amore precisereevaluation of the expression profile of B19V genome indifferent cell types was obtained by means of quantitativePCR analysis first assessing the relative abundance of distinctregions of the viral genome within the mRNA complement[105] and then by using a redundant PCR array to determinethe relative frequency of the diverse species of mRNAs [106]

In permissive cellular environments such as in bonemarrowmononuclear cells UT7EpoS1 and KU812Ep6 cellsviral DNA is observed to increase within 48 hpi rarely

exceeding 2 logs with respect to input DNA viral RNA isalready present within 2ndash6 hpi its increase preceding thatof viral DNA up to 36ndash48 hpi and all the different classesof viral RNA are constantly represented in stable relativeamounts throughout the infection cycle In nonpermissivecells such as TF-1 cells viral DNA does not increase andonly the spliced proximally cleaved viral mRNAs can bedetected inminimal amountsThese data indicate that the B19virus genome should be considered a single replicative andtranscriptional unit characterized by a two-state expressionprofile either silent and nonreplicating or transcriptionallyactive and replicating [105] Then within the single andcompact transcriptional unit the presence and utilization ofsplicing and cleavage-polyadenylation signals would deter-mine the relative abundance of the different RNA speciesUtilization of the processing signals is relatively constantthroughout the viral infection cycle with the only differenceemerging as an early modulation in expression profiling ofthe viral genome linked to transition from a low-splicingprevalent pAp cleavage at earlier times after infection to ahigh-splicing balanced pAppAd cleavage at later times [106]an effect possibly linked to onset of replication of the viralgenome [103]

Overall such data indicate that the genome of B19V canbe considered as a single functional unit whose expressionprofile can be clearly differentiated depending on the degreeof intracellular restriction In nonpermissive cellular environ-ments the viral genome can be present but is silent while inpermissive cellular environments the genome is active andboth full transcription and replication of the viral genomeoccur resulting in a productive replicative cycleThe onset oftranscription which is assumed to be on a double-strandedtemplate generates a complete set of mature transcripts witha marginal temporal shift between immediate events theprevalent generation of unspliced and proximally cleavedtranscripts and delayed events with an increased generationof spliced and distally cleaved transcripts The generationof a full complement of viral mRNAs appears to occur andbe maintained before the onset of template replication thusblurring a distinction between early and late events andmaximal replication of the viral genome occurs as a finalevent in the presence of all species of viral mRNAs

A further level of regulation of viral expression can beat the epigenetic level [107] In this respect CpG DNAmethylation is one of the main epigenetic modificationsplaying a role in the control of gene expression For DNAviruses whose genome has the ability to integrate in thehost genome or to maintain as a latent episome a generalcorrelation has been found between the extent of DNAmethylation and viral quiescence Within the genome theinverted terminal regions display all the characteristic sig-natures of a genomic CpG island suggesting a possible roleof CpG DNA methylation in the regulation of viral genomeexpressionThe effects of DNAmethylation on the regulationof viral genome expression were investigated by transfectionof either unmethylated or in vitro methylated viral DNA ina model cell line and results showed that methylation ofviral DNA was correlated with lower expression levels of theviral genome Then in the course of in vitro infections in

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

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macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 9

different cellular environments such as UT7EpoS1 or U937cells it was observed that absence of viral expression andgenome replication were both correlated to increasing levelsof CpG methylation of viral DNA Finally the presence ofCpG methylation was documented in viral DNA presentin bioptic samples indicating its occurrence in vivo andsuggesting a possible role of this epigenetic modification inthe course of natural infections Viral nucleic acids can berecognized by cellular PRR such as TLR9 B19V genomelacks typical stimulatory motifs however its methylation ina typical CpG islands and the presence of an epigenetic levelof regulation of viral genome expression possibly correlatedwith the silencing of the viral genome and contributing tothe maintenance of the virus in tissues can be relevant tothe balance and outcome of the different types of infectionassociated with parvovirus B19

45 The Proteome The proteome potentially encoded byB19V appears to be limited [9 96 108ndash110] A total of sixORFs are distributed on the three positive strand frames asdepicted in Figure 1 and represented in several classes of viralmRNAs In the left half of the genome unspliced mRNAscontain a major ORF in frame 1 coding for NS protein Inthe right half of the genome single-spliced mRNAs contain amajor ORF in frame 2 encoding for VP1 and double-splicedmRNAs contain a portion of the sameORF encoding forVP2As both capsid proteins are coded from the same ORF inframe 2 it can be discerned a VP1 unique region (VP1u) anda VP1VP2 core region Two ORFs in frame 3 are present inthe middle and right end of the genome and have similartopographical relation with respect to spliced transcriptscleaved at the pAp2 and pAd sites and the potential tocode for a 9 kDa and 11 kDa proteins respectively A smalladditional ORF positioned in frame 2 ahead of the ORF forVP proteins has the potential to code for 75 kDa protein

However the RNA complement is only indicative ofthe potential viral proteome In fact posttranscriptionalregulation can also occur influencing the functional profileof B19V in infected cells An AUG-rich region upstreamof VP1 start codon absent in VP2 can act as a negativeregulatory element in the translational control of B19V capsidprotein production leading to a higher relative abundanceof VP2 [111] Strikingly mRNAs coding for viral capsidproteins might not be translated efficiently in some cellularenvironments such as UT7Epo cells [81 112] This effectwas specifically attributed to the 31015840 UTR of mRNAs codingfor the capsid proteins whose presence represses capsidprotein synthesis at the translational level by inhibitingribosome loading [113] Although codon optimization ofcapsid genes was shown to enhance capsid protein synthesisin nonpermissive environments [114] there is the possibilitythat suchmechanismsmight be regulated by humanmiRNAsspecifically targeting the viral mRNAs [115]

In the future a proteomic analysis approach will berequired for characterization of the whole viral proteomedefinition of posttranslational modifications of viral proteinsinvestigation of the dynamics and interactions of viralproteins produced in infected cells and of virus-inducedcellular alterations

46 NS Protein The NS protein is 671 aa protein (calcu-lated Mr 74 kDa) containing an SF3 helicase domain Innonstructural proteins of small viruses such as parvoviruspolyomavirus and papillomavirus a SF3 helicase domainis usually associated with an origin-binding domain Bypairing such domain with a helicase the protein binds to theviral origin of replication leading to origin unwinding thencellular replication proteins are recruited to the origin and theviral DNA is replicated Several structures of SF3 helicaseshave been solved but not that of B19V NS protein They allpossess the same core alphabeta fold consisting of a five-stranded parallel beta sheet flanked on both sides by severalalpha helices Finally the SF3 helicase proteins assemble intoa hexameric ring

B19V NS is a protein with nuclear localization producedearly in the replication of B19V but is detectable throughouta time course of infection NS protein is not associated withviral particles as other NS proteins of parvoviruses Withininfected cells B19V NS protein may also be present showingadditional forms of lower Mr but neither posttranslationalmodifications nor processing has been clearly documented[9 108] As discussed structural and functional predictionsindicate the presence of DNA binding endonuclease heli-case and transactivating domains Some of these activitieshave been documented experimentally

NS protein is essential for replication of B19V genome[62] NS operates on terminal structures of B19V DNAreplicative intermediates allowing terminal resolution andstrand unwinding necessary for priming of strand displace-ment synthesis [82] It can be assumed that its activity isalso necessary for strand unwinding in the packaging phaseof replicative cycle NS transactivates its own promoter [86]boosting viral macromolecular synthesis and promoting viralreplication

Heterologous transactivating activities have beenattributed to NS protein from the HIV LTR [116] to severalgenes involved in inflammatory responses Expression ofNS protein in heterologous cellular systems such as K562cells can promote production of the inflammatory cytokineinterleukin-6 (IL-6) but not the production of other relatedcytokines IL-1120573 IL-8 or TNF-120572 NS-primed IL-6 inductionis mediated by a NF-kB binding site in the IL-6 promoterregion strongly implying that NS functions as a transactingtranscriptional activator on the IL-6 promoter [117] Ina different system such as the monocytic cell line U937expression of a transduced NS gene can induce production ofTNF-120572 mRNA and protein in a manner associated with NSexpression AP-1 and AP-2 motifs on the TNF-120572 promoterare responsible for this NS-mediated upregulation [118]Although differing in the diverse cellular environments boththese mechanisms indicate a potential proinflammatory roleof NS protein

B19V NS protein shows various effects on the cellEarly reports indicated its cytotoxicity [119] that could beabolished by mutating its putative nucleoside triphosphate-binding domain [120] B19V NS protein was shown toinduce apoptosis in UT7EpoS1 cells as well as K562 cellsin a caspase-3 dependent pathway separate from the IL-6activation pathway [121] In human erythroid progenitors

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Stem CellsInternational

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

10 ISRN Virology

CD36+ cells B19V infection andNS expression both inducedDNA fragmentation characteristic of apoptosis and thecommitment of erythroid cells to undergo apoptosis wascombined with their accumulation in the G(2) phase of thecell cycle B19V- and NS-induced apoptosis was inhibited bycaspase 3 6 and 8 inhibitors and substantial caspase 3 6and 8 activities were induced by NS expression Fas-FasLinteraction was not involved in induction of apoptosis inerythroid cells but these cells were sensitized to apoptosisinduced by TNF-120572 suggesting a possible connection betweenthe respective apoptotic pathways activated by TNF-120572 andNSprotein in human erythroid cells [122]

47 VP Proteins Two VP proteins constitute the capsidshell VP1 and VP2 VP1 is a 781 aa protein (calculated Mr86 kDa) VP2 is a 554 aa protein (calculated Mr 61 kDa)Being derived from the same ORF the N-terminus of VP1constitutes the 227 aa long VP1u region that comprises theviral phospholipase domain In the VP12 common regionthese proteins share a beta-sandwich structure consistingof 8 beta-strands in two sheets with a jellyroll fold andcharacteristic interactions between the domains of this foldallow the formation of fivefold assemblies that lead to theformation of a 119879 = 1 capsid

Both proteins are produced and accumulate throughoutthe replicative cycle The relative abundance of the two pro-tein species is in part regulated by the relative abundance ofthe respective mRNAs in part from efficiency of translationinitiation [111] and also may depend on effects linked to the31015840UTR region of specificmRNAs [113] A nonconsensus basicmotif in the C-terminal region of VP12 mediates transportof capsid proteins to the nucleus where capsid assemblyand genome packaging may occur [123] As in the casefor NS protein neither posttranslational modifications norprocessing has been documented

Viral capsid proteins produced in eukaryotic expressionsystem have the capability of self-assembly and form viral-like particles (VLP) quite similar to native virions a propertyexploited for studies on capsid structure and assemblingdynamics The first systems utilized a genetically engineeredcell line [124] or B19-SV40 hybrid vectors and expression inCOS-7 cells [97 125] however the most widely used heterol-ogous system for the production of viral capsid proteins ableto formVLPs soon became the baculovirus expression systemin eukaryotic insect cells [126ndash128]

In the baculovirus expression system VP2 protein aloneis sufficient for formation of VLPs the percentage of VP1protein that may become incorporated in VLPs can rise fromthe normal 5 up to 40 at the expense of efficiency WhileVP1 protein alone cannot self-assemble in regular capsidsprogressive truncation of VP1u region restores the ability ofVP1 to form VLPs with normal morphology [129] Furthertruncation of the VP2 protein destroys the ability to formVLPs [130] In recombinant capsids most of the VP1 uniqueregion is exposed on the capsid surface [131] These datamay be in accordance with crystallographic comparison ofVP2- only VLPs obtained in an S cerevisiae heterologousexpression system with VP1+VP2 native virions that suggest

externalization of the VP2 N-terminal region and hence pos-sibly of VP1 [14] Furthermore our understanding of virionstructure needs to be reconciled with other data indicatingthe presence of a constituent PLA(2) activity in VLPs [80]or that the VP1u region becomes fully accessible and itsphospholipase active only following the initial interactionswith cell membranes [74]

48 The Small Proteins In B19V genome additional ORFsare present other than NS and VP proteins Of these twoare in frame 3 separate from the larger ones in the centerand the right end of the internal unique region and have thepotential to code for a 9 kDa and 11 kDa protein respectivelyAdditionally in frame 2 the same as VP proteins but ina position overlapping with the NS coding sequence asmall ORF has the potential to code for a 75 kDa proteinFunctional analysis obtained from a complete clone of B19Vgenome indicated an essential role for the 11 kDa protein tomaintain infectivity in contrast to a dispensable role for the9 and 75 kDa proteins [62]

Of these small nonstructural proteins the 11 kDa proteinis the best characterized [109] It is translated from thesmall double-spliced mRNAs cleaved at the pAd site as afamily of proteins 94ndash85 aa due to the presence of multiplestart codons It is a proline-rich protein presenting threeconsensus SH3-binding sites showing mainly cytoplasmiclocalization Its essential role in B19V infectivity seemsrelated to posttranscriptional events necessary for obtainingadequate amounts and a correct distribution pattern ofcapsid proteins In vitro interaction has been demonstratedwith host cell factors such as receptor-binding protein 2(Grb2) [132] and perhaps the role of the 11 kDa protein canbroadly act in altering the cellular environment to favor viralreplication and maturation In addition a role of the 11 kDaprotein in inducing apoptosis of EPCs via caspase 10 has beenshown [133]

The expression of the predicted 9 kDa 81 aa protein hasnot been actually traced in infected cells Such protein wouldbe translated from a highly conserved ORF within the smallsingle-spliced mRNAs cleaved at the pAp2 (but not pAp1)site that constitute only a minor fraction of viral mRNAsIn heterologous expression system this protein exerts atransactivating effect on the P6 promoter comparable to thatof NS protein [134] Finally a 75 kDa 74 aa protein might betranslated from a small ORF present only in mRNAs splicedat the D1A2-1 sites Its expression in infected cells has beenshown in an early report [110] but it does not exert anydemonstrated function

49 Assembly Maturation and Egress The last phases of theviral infectious cycle are poorly characterized VP proteinsare transported to the nucleus where they can assembly intocapsid and incorporate the viral genome to be then reex-ported in the cytoplasm By electron microscopy empty orfull DNA-containing viral particles can be observed withininfected cells in scattered distribution or paracrystallinearrays [135]These terminal phases of the replication cycle areprobably tightly regulated and may require helper functions

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

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International Journal of

Microbiology

ISRN Virology 11

for example a role suggested for the viral 11 kDa proteins Asmentioned the production of VP proteins and the yield ofinfectious virus can be hampered in some cellular systemso a further level of restriction to a productive cycle maybe linked to the efficiency of the packaging maturation andegress processes

410 Cell Tropism Restriction and Effect on Cells Thedistribution of viral receptors and coreceptors main andalternative accounts for the tropism of the virus not onlytowards its main target cells but also for the interactionof virus with many diverse cell types On the other handreplication of the virus appears to be highly restricted indifferent cell types and even within a cellular populationTheidentification of the cellular factors involved in restriction orpermissivity to viral replication and the definition of whateffects the virus may exert on the different cell types as afunction of its replicative cycle are major fields of interest

Characteristics of the viral replicative cycle and theeffects of infection on cell physiology have been studied inthree main different contexts First most studies have beenperformed on model cell lines The UT7EpoS1 cell line hasbeen widely used because of its relative high susceptibilityto infection although the system is basically restrictive andthe yield of infectious virus is very low Second manystudies have recently taken advantage from the capability inobtaining primary cell cultures of defined erythroid lineageat different stages of differentiation In these cases theinteraction is probably very similar to what may happenin natural infections Third investigation in many instancesinvolved cell types primary cells or cell lines different fromstandard target cells either to investigate relationships withdiverse cell types that may occur in the course of naturalinfections or as in vitro systems amenable to experimentalmanipulation In these last cases results should always beconsidered as possible evidence waiting for validation in anatural context

411 Cellular Permissivity Almost all cells that can be pro-ductively infected by B19V require Epo for growth [43 55]Epo is required to promote growth of these permissive celltypes but also the direct involvement and activation ofEpoR and activation of downstream signal transduction arenecessary to achieve a productive replication [136] In factCD36+ EPCs grown in the absence of Epo do not supportB19V replication in spite of B19V entry but Epo exposureenables active B19V replication Jak2 phosphorylation inhi-bition inhibits phosphorylation of the Epo receptor (EpoR)and abolishes B19V replication in ex vivo expanded erythroidprogenitor cells exposed to Epo Thus EpoR signaling isrequired for B19V replication in ex vivo expanded erythroidprogenitor cells after initial virus entry and replicationresponse is dose dependentThese effects may partly accountfor the restriction of productive B19V infection in humanerythroid progenitors

Hypoxia also promotes replication of B19V [94] Inparticular in cultured EPC hypoxia promotes replication ofthe B19V genome independent of the canonical PHDHIF120572

pathway but dependent on STAT5A and MEKERK signal-ing Simultaneous upregulation of STAT5A signaling anddownregulation of MEKERK signaling boost the level ofB19V infection in erythroid progenitor cells under normoxiato that in cells under hypoxia B19V infection of ex vivoexpanded erythroid progenitor cells at hypoxia closely mim-ics native infection of erythroid progenitors in human bonemarrow where hypoxia is physiological hence the responseof virus to hypoxia can be regarded as an adaptation of virusto the environment of its primary target cells [137]

The block to replication of B19V genome in nonper-missive cellular environments can also be overcome byhelper functions provided by adenovirus infection In theUT7EpoS1 cells B19V DNA replication can be enhancedby adenovirus infection In the nonpermissive 293 cells thereplication of transfected B19V DNA and the production ofinfectious progeny virus were made possible by expressionof the adenovirus E2a E4orf6 and VA RNA genes [82] Inparticular E4orf6 is able to promote B19V DNA replicationresulting in a concomitant increase in VP expression levelswhile VA RNA induces VP expression in a replication-independent manner [138]

412 Deregulation of the Cell Cycle InUT7EpoS1 cells infec-tion with B19V induces growth arrest with 4N DNA contentindicating G(2)M arrest These B19V-infected cells displayaccumulation of cyclin A cyclin B1 and phosphorylated cdc2and show an upregulation in the kinase activity of the cdc2-cyclin B1 complex Accumulation of cyclin B1 is localized inthe cytoplasm but not in the nucleus suggesting that B19virus infection suppresses the nuclear import of cyclin B1resulting in cell cycle arrest at the G(2) phase and preventingprogression to the M phase The B19 virus-induced G(2)Marrest may be the critical event in the damage of erythroidprogenitor cells seen in patientswith B19 virus infection [139]In the presence of mitotic inhibitors B19V infection wasshown to induce not onlyG(2) arrest but alsoG(1) arrest UV-irradiated B19V still has the ability to induce G(2) arrest butnot G(1) arrest the B19V-induced G(2) arrest is not mediatedby NS expression while expression of NS can induce cellcycle arrest at the G(1) phase [140] NS expression increasesp21WAF1 expression a cyclin-dependent kinase inhibitorthat induces G(1) arrest an effect mediated by interactionwith Sp1 transcription factor [141] Thus also G(1) arrestmediated by NS may be a prerequisite for the apoptoticdamage of erythroid progenitor cells upon B19V infection

In primary human CD36+ EPC culture system cellularfactors that lead to cell cycle arrest after B19V infection haveextensively been studied by microarray analysis It has beenshown that B19V exploits the E2F family of transcriptionfactors by downregulating activating E2Fs (E2F1 to E2F3a)and upregulating repressive E2Fs (E2F4 to E2F8) NS proteinis a key viral factor responsible for altering E2F1ndashE2F5 expres-sion but not E2F6-E2F8 expression Interaction between NSand E2F4 or E2F5 enhances the nuclear import of theserepressive E2Fs and induces stable G2 arrest NS-induced G2arrest is independent of p53 activation and leads to increasedviral replication In this model downregulation of E2F target

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

12 ISRN Virology

genes eventually impairs the erythroid differentiation whileviral DNA replication and RNA transcription are enhancedby activation of G2-related transcription factors andor DNArepair proteins This in turn may cause activation of the p53signal transduction and upregulation of E2F7 and E2F8 aspart of a DNA damage response that may contribute to theof block cell cycle progression [142]

413 B19V and Cellular DNADamage Response The involve-ment of the cellular DNA damage response (DDR) machin-ery in the regulation of B19V replication and in turn onprogression through cell cycle has been then investigatedB19V infection of EPCs has been shown to induce a broadrange of DNA damage responses by phosphorylation ofall the upstream kinases of each of three repair pathwaysDNA-PKcs ATM (activated by double-stranded breaks) andATR (activated by single-stranded breaks) Activated DNA-PKcs ATM ATR and also their downstream substrates andcomponents localize within the B19V replication centersVirus replication requires ATR and DNA-PKcs signalingand in particular the ATR-Chk1 pathway is critical to B19Vreplication [143] None of the viral proteins acts as initiatorsof a DDR that is induced by replication of the B19V dsDNAgenome Moreover the DDR per se does not arrest the cellcycle at the G(2)M phase in cells with replicating B19VdsDNA genomes instead the B19VNS protein is the key fac-tor in disrupting the cell cycle via a putative transactivationdomain operating through a p53-independent pathway [144]

414 Apoptosis and Autophagy B19V infection of erythroidprogenitor cells induces apoptosis leading to a block inerythropoiesis that is one of the most relevant componentsof the pathogenetic processes due to the virus [145] Infectedcells showmorphological alterations typically associatedwithapoptotic processes and typical DNA fragmentation [146] Asdiscussed above NS protein is responsible for cytotoxicityand is implicated in induction of apoptosis in CD36+ EPCsand UT7EpoS1 cells [121] In addition the nonstructural11 kDa protein has also been reported as capable of sig-nificantly inducing apoptosis in EPCs Moreover caspase-10 an initiator caspase of the extrinsic pathway has beenreported as the most active caspase in apoptotic erythroidprogenitors induced by 11 kDa and NS as well as duringB19V infection [133] Additionally mitochondrial autophagyhas been described in B19V infected UT7EpoS1 cells Asignificant increase of the protein expression ratio for LC3-IILC3-I in infected cells and confocal microscopy analysessuggested that B19V infection induced the formation of anintracellular autophagosome and inhibition of autophagysignificantly facilitated B19V infection-mediated cell deathThen in contrast to B19V-induced apoptosis B19V-infectedcells may improve survival by autophagy mechanisms [147]

415 Nonpermissive Systems In the human monocytic cellline U937 an in vitro infection study demonstrated B19Vbinding and modest replication with detectable NS mRNAtranscription but undetectable levels of VP mRNA tran-scription suggesting abortive infection Levels of B19V

DNA and NS mRNA transcription increased in the pres-ence of anti-B19 IgG antibodies but this effect decreasedin the presence of anti-Fc receptor antibodies show-ing antibody-dependent enhancement of B19V infectionAntibody-dependent enhancement also caused the increasedproduction of TNF-120572 This study showed B19V infection ofnonerythroid lineage cells possibly mediated by antibody-dependent enhancement leading to abortive infection but adetectable proinflammatory response [148]

In addition to erythroid progenitors cells of connectiveand vascular tissue could be involved in the pathogenesisof B19V infection Primary cultures of human fibroblasts(HF) and human umbilical vein endothelial cells (HUVEC)exposed to B19V can be infected but only low levels ofNS and VP mRNAs might be detected in the absence ofany significant increase of B19V DNA levels Then HF andHUVEC are normally not permissive for B19V replicationbut it is possible that stimulation with different growthfactors or cytokines could be required for a B19V productiveinfection to occur [149] In an experimental system usinga human endothelial cell line HMEC-1 B19V infection orNS overexpression produced a significant upregulation in thephosphorylation of STAT3 accompanied by dimerizationnuclear translocation and DNA binding of pSTAT3 withoutincreased STAT1 activation The expression levels of thenegative regulators of STAT activation SOCS1 and SOCS3were not altered but the level of PIAS3 was upregulatedin NS-expressing HMEC-1 cells Analysis of the transcrip-tional activation of target genes revealed that NS-inducedSTAT3 signaling was associated with upregulation of genesinvolved in immune response and downregulation of genesassociated with viral defense The NS-induced upregulationof STAT3PIAS3 in the absence of STAT1 phosphorylationand the lack of SOCS1SOCS3 activation may contribute tothe mechanisms by which B19V evades the immune responseand establishes persistent infection in human endothelialcells [150] In endothelial cells of different types infected withB19V or transfectedwith the B19V genome subsequent aden-ovirus infection led to a limited B19V genome replication andsynthesis of B19V structural and nonstructural proteins Thiseffect was mostly mediated at the level of transcription andcan be attributed to transactivation by adenovirus E1A andE4orf6 which displayed synergistic effects Thus the almostcomplete block in B19V gene expression in endothelial cellscan be abrogated by infection with other viruses [151] Onthe whole these studies point to the relevance of endothelialcells for the biology of B19V Endothelial cells may constitutea diffuse target cell population where virus can establish areservoir and where the cell physiology may have a decisiverole in determining the degree of expression of the virus andthe balance toward the activation of possible pathogeneticmechanisms

B19V DNA can be detected in synovial cells and fluidhowever already an early report indicated that synoviocytesare nonpermissive to B19V replication [152] In a follow-ing report B19V DNA detected in the synovial tissues ofpatients with rheumatoid arthritis was specifically linked tothe expression of the VP in synovium with active synoviallesions In this case the identified target cells of B19V were

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

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juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

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receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

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International Journal of

Volume 2014

Zoology

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Molecular Biology International

GenomicsInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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BioinformaticsAdvances in

Marine BiologyJournal of

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Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Nucleic AcidsJournal of

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Stem CellsInternational

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 13

macrophages follicular dendritic cells T cells and B cellsbut not synovial lining cells in the synovium These cellswere considered productively infected as susceptible cellsbecame positive for the expression of viral proteins and moreproductive for IL-6 and TNF-120572 when cocultured with RAsynovial cells These data suggested a direct role for B19Vin the initiation and perpetuation of RA synovitis leadingto joint lesions [153] Unfortunately these data did not findcorroboration in subsequent studies

Although synoviocytes are nonpermissive to viral replica-tion exposure to B19V induces an invasive phenotype [154]A possible mechanism may involve the direct interaction ofB19V capsid with their VP1u-associated PLA(2) activity andsynoviocytes [155] Even if B19V does not productively infecthuman fibroblast-like synoviocytes (HFLSs) it can inducean increase in synoviocyte migration that can be blocked byphospholipase inhibitors Recombinant proteins with intactVP1u and PLA(2) activity induce cell migration whereasproteins with mutated VP1u are nonfunctional The incuba-tion of HFLSs with intact VP1u but not with mutated VP1uincreases the production of prostaglandin E(2) Expressionof cyclooxygenase (COX)-2 mRNA transcripts and COX-2 protein expression were both significantly increased afterincubation with intact VP1u Then even in the absence ofa productive infection of synoviocytes the interaction ofsynoviocytes with B19V capsids showing PLA(2) activitymay play a pathogenetic role by inducing an inflammatoryresponse in the synovial compartment

416 Virus Persistence Following in vitro infections carriercultures can be established for a limited period of timeFor example in the semipermissive UT7 cells after a fewrounds of productive replication the virus can still be detectedfor extended periods of time showing a progressive loss ofactivity [55 107] and also in nonpermissive systems such asU937 cells the viral DNA can be maintained within cells forsome time in the absence of detectable viral activity [107]These systems may mirror what happens in vivo In factpresence of viral DNA has been detected in a wide range oftissues in normal populations as well and with comparablefrequency as from selected group of patients with diversepathologies

Bone marrow is the main target organ of B19V so thevirus can normally be detected in bone marrow also incases of persistent infections with constant low-level viremiahowever detection of viral DNA has also been reported innormal subjects without evidence of active viral replicationat frequencies of about 60 [156ndash158] Viral DNA has beenreported in lymphoid tissue including spleen lymph nodesand tonsils [32 158] Liver frequently shows the presence ofB19VDNA [32 33 159] and in the heart the presence of B19VDNA is also a common finding [34] that has been the focusof an ongoing debate on its potential role in the developmentof cardiomyopathies [160] Viral DNA is commonly foundin synovial tissues [32 157 161] and skin [32 162] Finallythe virus has also been found in brain [158] and testiculartissues [163] So the initial picture of a virus capable ofacute infections and rapidly cleared by the organism as a

consequence of the immune response has given place to thepicture of a virus able to establish long-term relationship withhuman hosts and the current assumption is that persistenceof viral DNA in tissues can be the normal outcome ofinfections [32]

Relevant issues are what cells can harbor the virus inwhat form this viral DNA is present within cells what canits functional profile be and what the consequences on thecell physiology are but most information in these respectsis lacking The presence of viral DNA in tissues is a distinctevent from persistence of productive infection a commonclinical finding characterized by ongoing replication in thebonemarrow and usually low-level viremia It is assumed thatthe viral genome can be maintained in an episomal formjust because the evidence for its integration in the cellulargenome has never been reliably reported However no datahave been reported neither on its possible configuration sothis is only speculative by comparison to what is known forarrangements of other parvoviruses for examplemonomericversus concatemeric or linear versus circular nor on itsability to form chromatin structures The presence of full-length viral genomes in tissues has been reported [164] but asviral DNA is usually detected by PCR amplification of distinctsegments of the viral genome there is the possibility thatin other instances only fragmented nonfunctional DNA ismaintained within tissues

Within tissues unless in the presence of a high viral loador expression of mRNAs or proteins at detectable levels theviral genome is normally considered silent [34] A possibilityis that the virus might establish true latent infections withthe capability of reactivations but this has only rarely beensuggested and not fully documented Epigenetic levels ofregulation may play an important role in the control of viralexpression and determining a silencing of persistent viralDNA [107] Since effects on cell physiology would probablydepend on the expression of viral proteins impacting cellularpathways a silenced genome would not alter a cellularenvironment by definitionThe opposite is probably true andit is the cellular physiology that would determine a possibleexpression of a viral genome harbored within the cell

5 Pathogenesis

51 Course of Infection The course of infection was firstinvestigated in two set of experiments involving humanvolunteers who were inoculated and followed with respectto virological immunological hematological and clinicalparameters [165 166] These studies constituted a frameworkfor the definition of a pathogenic profile of B19V infectionthat since then increased in scope and complexity The virusis now implicated in a wide range of clinical manifestationsthat necessarily rely on a complex relationship of virus itsbiological characteristics host its physiological status andcapacity of immune response

52 Early Events Following contact via the respiratory routethe virus gains access to the bloodstream Persistence of theviral DNAhas been detected in tonsillary tissues [32 158] but

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Volume 2014

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International Journal of

Microbiology

14 ISRN Virology

it is not known whether tonsils can constitute a true portalof entry if virus can undergo a first round of replicationin tonsils and to what extent lymphoid vessels are involvedin spreading or maintenance of infection An alternativemechanism of access to vessels could be transcytosis throughrespiratory epithelia

Then in a primary viremic phase that normally is unde-tected the virus gains access to the primary target organthe bone marrow where it can infect erythroid progenitorcells achieving a productive infection and exerting cytotoxiceffects In this phase the bone marrow can show erythroidaplasia and the presence of characteristic giant erythroblaststhat are considered pathognomonic of B19V infection Theseeffects are mirrored in the capability of the virus to inhibitthe formation of bone-marrow-derived erythroid coloniesat the BFU-E and CFU-E stages [40] with susceptibilityto infection and cytotoxic effects increasing with increasingerythroid differentiation [145] The generation of EPCs fromperipheral blood and the study of their susceptibility toinfection confirmed an increasing susceptibility to virus witherythroid differentiation [53 54] Thus the target cells inbone marrow are CD36+ cells and are mostly susceptiblewhen in the differentiating phase (erythroblasts) The effectson bone marrow are derived from the ability of virus toinduce cell-cycle arrest block of erythroid differentiationand eventually apoptosis of susceptible and infected cellsand from the dimension and turnover rate of the erythroidcompartment The fact that the more undifferentiated pre-cursors are relatively resistant to infection ensures that theblock in erythropoiesis is temporary and can be relievedby a neutralizing immune response Other cellular typespossibly susceptible to infection are themegakaryoblasts thathowever constitute a nonpermissive cellular systemwhere thevirus may exert a cytotoxic effect in the frame of an abortiveinfection [167]

In fact a balance is reached between cell populationdynamics and viral replication considering also possiblestresses on the erythropoietic compartments and the immuneresponse [168] In a normal individual with physiologicalerythropoiesis and normal immune response infection islimited in extent and temporal frame and is controlled bythe development of a specific immune system Productionof antibodies with neutralizing activity contributes to theprogressive clearance of infection Levels of hemoglobin onlymarginally decrease and infection is usually asymptomaticfrom the hematological point of view Clearance of infectiondetermined by detection of virus in the blood can berelatively rapid taking usually 3-4 months with constantlydecreasing levels even if very low levels of virus can bedetected for years following primary infection [169ndash171] Thevirus can still be detected in the bonemarrow of a percentageof individuals [156ndash158] however persistence of viral DNAimplicates active chronic infection only in the presence ofviremia

Infection becomes manifest as pure red cell aplasia(PRCA) and anemia when preexisting alterations in the ery-thropoiesis process or defects in the immune response alterthe balance between viral replication and cellular turnover[168 172] In case of stressed and expanded erythropoietic

compartment in situations where the number of erythroidprogenitors and their replication rate are expanded because ofa reduced lifespan of erythrocytes or increased need infec-tion byB19V can lead to an acute episode of profound anemiathat presents as the classical aplastic crisis in patients withunderlying hematological disorders The range of situationsfavorable to the development of acute B19-induced PRCAand anemia can be very ample from hemoglobinopathies tothalassemia from enzymatic defects to iron deficiencies tocoinfection with other viruses microorganisms or parasites

On the opposite when the immune system has not thecapability to control neutralize and clear viral infectioninfection can become persistent with active viral replicationand the involvement to different degrees of erythroid com-partment These situations can be typical of congenital oracquired immunodeficiencies such as HIV infection [173] incases of malignancies [174] in the course of chemotherapy[175] or in the course of immunosuppressive treatmentssuch as in bone marrow or solid organ transplant recipients[176ndash178] Depression of erythropoiesis can be manifestwith anemia of different grade but also compensated andunapparent A general correlation may be present betweenviremic levels and anemia but a clinical threshold has notbeen univocally defined as very high-level viremia may becompensated by active erythropoiesis On the other handthe definition of inability to mount a neutralizing immuneresponse must take into account that many normal andasymptomatic individuals support low-level replication ofthe virus The distinctions between a normal course andactive chronic infections are smooth and again we shouldtake in mind that our picture of B19V as a virus capable ofacute self-limiting infections has been replaced with a morecomplex picture of a virus capable of establishing long-termrelationship with the host in a mutual adaptation

53 Late Events Bone marrow supports a productive infec-tion and leads to release of progeny virus in the bloodleading to a secondary viremia that is the mark of activeinfection and that in the acute phase of infection beforethe development of an effective immune response can reachexceedingly high viremic levels (1012 virusmL) before aprogressive clearance The secondary viremic phase leads tothe systemic distribution of the virus and preludes to possiblelate clinical manifestations of infection The two classicalmanifestations of B19V infection are erythema infectiosumtypical of children [179 180] and arthropathies typical ofadult patients [181 182] Since the initial reports the rangeof clinical manifestations associated with B19V infectionhas been constantly increasing to involve almost all organsand tissues and descriptions of clinical presentations haveprogressively stressed atypical aspects Strict criteria andsound methodologies should be always adopted to linkB19V infection and definite atypical pathological processesby demonstrating the presence of viral components andactivities in pathological tissues or closely associated clinicaland epidemiological parameters

When investigating pathogenetic processes possiblylinked to the systemic phase of B19 infection problems arise

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Microbiology

ISRN Virology 15

regarding the identification of secondary target cells thedefinition of the viral expression profile and virus-inducedalterations within these cells and the characterization of thedegree and role of the immune response In some instancesthe pathogenic process may depend upon direct cytotoxicor proapoptotic effects of viral proteins and in some it maydepend upon stimulation of an inflammatory response byviral proteins such as theNS protein or theVP1u PLA(2)Theinterplay with the immune systems by its innate and adaptiverecognition mechanisms may lead to the development ofimmunopathological mechanisms or autoimmune processesthat also have been described [183 184]

In the systemic phase of infection cells of mesodermicorigin are mainly involved [70] and of these endothelial cellsmay play a central role Endothelia constitute a diffuse tissuethat can account for the wide distribution of virus and thedetection of its genome in disparate organs Endothelial cellscan be infected by B19V and normally nonpermissive [151]can be a site of persistence of the viral genome as it happensfor many other viruses In some cases however markersof viral activity have been precisely localized to epithelialcells within diverse tissues and organs and causally linked topathological processes so the question is in what situationsendothelial cells can become permissive to the virus Anothergeneral assumption is that some typical manifestations ofinfection such as the erythema are due to immune complexformation and deposition with development of inflamma-tory responses In fact immune recognition mechanismsleading to pathological processes have been described inseveral instances and will contribute to the general clinicalpicture of B19V infection

54 Cardiomyopathies In recent years B19V gained interestas a cardiotropic virus In a sort of wave B19V has beendetected at ever-increasing frequencies in endomyocardialtissues replacing other cardiotropic viruses as the mostprevalent virus detected in the heart [185ndash187] This isprobably linked to a growing interest in the virus andalso to the development of high-sensitivity and quantitativePCR detection methods however the data may also reflecta true epidemiological phenomenon although not readilyexplainable given the relative uniformity of viral isolates

B19V has been directly involved as an etiologic agent inacutemyocarditis both in pediatric [188ndash192] and adult popu-lations [193ndash195]The course of diseasemay be severe and notreadily diagnosed In the course of myocarditis active B19Vinfection has been shown in myocardial endothelial cellsthen B19V probably acts by inducing endothelial dysfunctionwhich in turn triggers inflammatory responses in the cardiactissue [193 196] The rare occurrence of clinically relevantmyocarditis compared to the widespread diffusion of B19Vinfections underscores the relevance of coincident factorsthat are presently ignored

The frequency of B19V DNA detected in cardiac biopticsamples is constantly high also when compared to that ofclassical cardiotropic viruses such as enteroviruses and amarked cardiotropism should be mentioned as one of themain characteristics of B19V As a possibility given adequatetissue sampling and sensitive detection methods the

presence of B19V DNA in endomyocardial bioptic samplesmight be expected in every individual previously infected byB19V Then it is not straightforward to assign a pathogeneticrole to B19V on the basis of the distribution of prevalenceof B19V DNA within selected groups of patients or controls[160] In particular the definition of a possible role of B19Vin the development of chronic cardiomyopathies and cardiacdysfunction is a matter of ongoing debate Correlationbetween B19V and cardiomyopathies in particular dilatedcardiomyopathy and ventricular dysfunction has beenproposed by several studies comparing selected groups ofpatients versus controls [197ndash205] but on the opposite alack of significant clinical association has been supported byother groups [206ndash212]

A positive association and an etiopathogenetic role ofB19V in the development of chronic cardiomyopathies havebeen proposed on the basis of significant higher frequenciesof detection in patient versus control groups or on thepresence of higher mean viral loads suggesting active viralreplicationThe degree of immune response either activationof innate immune system as hinted by cytokine levels or spe-cific anti-B19V immunity can also be considered as a clue toa role for B19V in the development of cardiomyopathies Thefocal point in a pathogenetic mechanism would be the abilityof the virus to induce endothelial dysfunction within cardiactissue which in turn would trigger inflammatory processesleading to the development of chronic cardiomyopathies Inthis scenario endothelial dysfunction might be triggered byviral-dependent mechanisms and be a consequence of viralreplication andor expression of viral proteins for exampleNS andor VP1 In alternative endothelial dysfunction maybe a consequence of the response to the presence of virusthrough innate recognition mechanisms More studies willbe necessarily required to investigate possible pathogeneticmechanisms at the cellular level and associate these to whathas been observed at the clinical and epidemiological levels

55 Arthritis and Rheumatic Diseases B19V has been recog-nized as an agent responsible for arthropathies since the earlystudies [181 182] Accumulated evidence and case series haveshown that B19V can cause acute arthritis or arthralgias andoccasionally chronic arthropathies Arthritis can develop inchildren at lower frequencies (lt10) accompanying or fol-lowing the classical erythema and is usually asymmetric andpauciarticular Arthritis and arthralgias are more commonclinical manifestations in adults in many cases presentingwithout concurrent symptomsmore frequent in females thanmales respectively presenting in approximately 60 or 30of documented infections In adults the typical onset is acutesymmetrical and involving mainly the small joints of handsand feet Chronicization has been reported for children but ismore frequent in adult patients up to 20 of cases in affectedwomen Chronic infections are usually self-limiting and donot lead to joint erosions and damage however in somecases they meet clinical diagnostic criteria for rheumatoidarthritis can be erosive and followed by the development ofrheumatoid factor [213]

The association of B19V infection and the actualdevelopment of chronic destructive arthropathies such as

16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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16 ISRN Virology

juvenile idiopathic arthritis and rheumatoid arthritis hasbeen the subject of continuous interest and conflicting resultsA pathogenetic role for B19Vhas also been proposed for otherrheumatic diseases such as among others chronic fatiguesyndromefibromyalgia systemic sclerosis vasculitis andsystemic lupus erythematosus Suggestions of the involve-ment of B19V in the pathogenesis of rheumatic diseasesmay come either from a parallelism in the pathogeneticmechanisms or from clinical and laboratory findings inselected groups of patients but in most cases the associationis controversial at the epidemiological level and not corrobo-rated by strong virological evidence [214]

In vitro synoviocytes are nonpermissive to B19V [152]although they can respond to infection and assume an inva-sive phenotype [154] suggesting a parallel role in the patho-logical processes within synovia Synovial tissues commonlyharbor B19V DNA and its mere presence is not correlatedwith any distinct pathological process [157 161] Thereforeany pathogenetic mechanisms linked to B19V would requirethe expression of viral genes such as the NS protein withits transactivating activity or the VP1 protein with its phos-pholipase activity capable of activating and maintaining aninflammatory response targeted to the synovial tissue Apossible similar mechanism involving macrophages den-dritic follicular cells and lymphocytes rather than synovialcells has been reported in tissues from rheumatoid arthritispatients [153] but awaits confirmation and further investiga-tion The involvement of lymphocytes possibly productivelyinfected by B19V has also been reported in a case seriesof chronic inflammatory joint diseases [215] and can be arare and unexpected finding in atypical clinical situationscharacterized by chronic inflammation [216]

A common concurrent phenomenon is the production ofautoantibodies in the course of infection that can also act asa possible trigger to the induction of autoimmune diseasesIn the acute phase of infection heterologous cross-reactiveand self-reactive antibodies can normally be producedThesecan be confounding factors in the diagnosis of disease butnormally do not play a substantial role in the pathogeneticprocess In some cases autoantibodies may persist andfunction as cofactors in the establishment of autoimmuneprocesses [217ndash219]

56 Intrauterine Infection and Fetal Damage A relevantproperty of B19V is its ability to cross the placental barrierand infect the fetus This characteristic was recognized earlyin the studies on B19V [220] and since then many studieshave been dedicated to assess the risk of intrauterine infectionin pregnant women the extent of consequences for the fetusand the involved pathogenetic mechanisms

The viral receptor globoside is present on the villoustrophoblast layer of human placenta and its expressionlevels highest in the first trimester progressively decreaseuntil vanishing in the third trimester This temporal changebroadly correlates with what is observed on the frequencyof transmission of infection to the fetus [221] Trophoblastsare not permissive to the virus but may bind viral capsidvia the globoside receptor hence their role in facilitatingtranscytosis of virus to the fetal circulation [222] Both

inflammatory [223] and apoptotic [224] aspects have beenobserved in placental tissues in case of B19 infection probablycontributing to fetal damage Endothelial placental cells canbe productively infected facilitating the establishment offetal infection and contributing to placental damage [225]When in the fetal circulation the virus can infect erythroidprogenitor cells in liver andor bone marrow depending onthe gestational age and can be detected in cells circulatingin the vessels of several tissues [226 227] as well as in theamniotic fluid [228 229] The block in fetal erythropoiesiscan be severe because of the physiologically expanded ery-thropoietic compartment combined to an immature immuneresponse and lead to fetal anemia tissue hypoxia possibledevelopment of nonimmune hydrops andor possible fetaldeath [230 231] Fetal cardiomyocytes contrary to adultare reported to possess the viral receptor and be susceptibleto infection therefore direct infection of these cells mayinduce fetal myocarditis that will contribute to fetal damage[232 233]

The natural course of fetal infection is affected by severalfactors First of all the immune status of the mother plays aprominent role as the presence of specific IgG in maternalserum is assumed to be protective towards infection of thefetus Therefore intrauterine infections should be confinedto the case of primary infections in nonimmune pregnantwomen In this situation the effective rate of transmissionwill depend on the gestational age being higher in the firsttwo trimesters possibly because of different expression ofgloboside on the placenta The effect on the fetus will alsodepend on its developmental stage depending on the rate ofexpansion of its erythroid compartment and maturity of fetalimmune response As a consequence infections occurring atearlier stages carry a higher risk of leading to fetal deathswhile the development of hydrops is more frequent in thecentral part of pregnancy Hydrops may lead to fetal deathor the fetus may more frequently recover without persistentdamage In the third trimester transmission is more difficultand fetuses are relatively resistant so the overall risk of fetaldamage decreases to background values [234] Some caseseries also reported a high frequency of detection of B19DNAin late intrauterine deaths [235ndash237] a finding not confirmedin other case series that did not show such correlations andindicated that late intrauterine fetal death is a rare event[238] Finally the infected fetusmay show presence of virus atbirth [239 240] Congenital infections have been sporadicallyassociated with neonatal anemia or anomalies [241] whiletheir possible consequences on the neurological developmentare currently investigated [242ndash244]

6 Immune Response

61 Innate Immunity The role of innate immunity in con-trasting B19V infection has not been investigated in detail Ingeneral like other viruses B19Vmight be recognized throughits PAMPs by cellular PRRs but what component of the virusmay act as PAMPs needs to be defined The viral genomeis devoid of stimulatory sequences however its terminalregions are GC rich and can possibly be recognized by

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 17

receptors such as TLR9TheCpG-ODN2006 is a TLR9 ligandwith phosphodiester backbone that selectively inhibits burst-forming unit-erythroid growth and induces accumulationof cells in S and G(2)M phases and an increase in cellsize and frequency of apoptotic cells features similar tothose observed in erythroid progenitors infected with humanparvovirus B19V A consensus sequence also located in theP6-promoter region of B19V can inhibit erythroid growthin a sequence-specific manner and downregulate expressionof the erythropoietin receptor effects also induced by B19VDNA Although TLR9 mRNAs were not upregulated bystimulation with ODN 2006 these results hint at possiblediverse mechanisms of inhibition of erythropoiesis [245]A recent study investigated the variation in expression ofdefensins and toll-like receptor in COS-7 cells transfectedwith different expression vectors producing EGFP-fused NSandVPproteins In this systemNSwas shown to play amajorrole in inducing both short- and long-term upregulationof defensins and TLR9 with some effects also played byVP2 protein The different effects of NS and VP2 on thestimulation of defensins and TLRs could provide a clue inunderstanding the roles of B19V on innate immunity [246]

62 Adaptive Immunity Antibodies Antibodies are the hall-mark of the adaptive immune response to B19V In naıveindividuals B19V specific antibodies is produced early afterinfection and are assumed to be able to neutralize viralinfectivity and progressively lead to clearance of infectionIgM are produced first and can usually last about 3ndash6monthsfollowing infection soon followed by production of IgG thatis assumed to be long-lasting IgA can also be detected in bodyfluids

Viral capsid proteins are the major antigens recognizedby the immune system and inducing the production of anti-bodies with neutralizing activity From an antigenic point ofview viral capsid proteins show epitopes on the VP commonregion or on the VP1u region Epitopes on the commonregion are mainly conformational and have been mappedin several regions dispersed on the capsid surface whileepitopes on the VP1u region are mainly linear and have beenmapped close to N-terminus [247ndash253] The development ofthe immune response typically shows the recognition of anacute-phase epitope followed by the development of higher-avidity antibodies [254 255] Amature and effective immuneresponse most frequently shows the presence of antibodies-directed anti-VP2 conformational and VP1u linear epitopes[255ndash260]

Antibodies to NS protein are also produced as a responseto B19V infection These can be detected in a subpopulationof individuals showing antibodies to capsid proteins infrequencies that have been reported to vary depending on thepopulation groups Antibodies to NS proteins are probablyproduced as a result of prolonged antigenic stimulationbut their presence has not been conclusively linked to anyparticular course of infection or clinical condition [261ndash268]

The immune reactivity to B19V proteins was furtherinvestigated by evaluating sera from healthy B19 IgG-positiveindividuals for antibody reactivity against linear peptides

spanning the NS protein or representative of selected anti-genic regions within the capsid proteins By this approachthree novel antigenic regions on the NS protein were iden-tified and three major antigenic determinants in the VP1uand VP common region have been mapped [269] The devel-opment of a neutralizing activity is typical of a mature andeffective immune response while antibodies with incompleteneutralizing activity are typical of persistent infections Thepresence of antibodies directed against viral capsid proteinsis assumed to protect from secondary infections and this maypose the rationale for the development of a vaccine

Then B cell enzyme-linked immunospot assay was usedto evaluate B19-specific B cell memory in volunteer donorsResult showed that a B cell memory is maintained againstconformational epitopes of VP2 and is absent against linearepitopes of VP2 Individuals seronegative for IgG against theunique region of VP1 have detectable B cell memory with thepotential to mount a humoral response on reexposure to B19The finding that B cell memory is established andmaintainedagainst conformational epitopes of VP2 and against linearepitopes of VP1 but not against linear epitopes of VP2 is inaccordwith what observed by testing serum reactivity againstdiverse B19 antigens [270]

63 Adaptive Immunity Cellular T-cell-mediated immuneresponses to B19V infection were first shown by measuringthe proliferative responses of peripheral blood mononuclearcells following in vitro stimulation by recombinant VP1VP2 and NS proteins Results indicated the presence ofB19V-specific cellular immunity directed against the capsidproteins VP1 and VP2 presented to CD4+ T cells by HLAclass II molecules [271] T-cell proliferation as a response tostimulation by B19V VLP antigen was then confirmed andmeasured in patients with recent as well as remote B19Vinfection showing that B19V-specific HLA class II-restrictedCD4+ cell responses were detectable most vigorous amongthe recently infected patients but not confined within theacute phase [272]

Following a different approach for the detection ofepitope-specific cell-mediated immunity a peptide librarywas designed to span the whole coding sequences of B19VNS protein and peptides used to detect specific CD8+ T-cell proliferative responses and cytolytic activity followingin vitro stimulation By this approach a single HLA-B35-restricted CD8+ T-lymphocyte epitope from the NS proteinwas identified its functional relevance also confirmed in exvivo experiments using an IFN-120574 Elispot assay This epitopewas strongly immunogenic in B19V-seropositive donors sug-gesting persistent antigen stimulation in normal individuals[273]

In an even more extensive approach to map T-cellepitopes a total of 210 overlapping peptides were synthesizedcovering the nonstructural protein NS the VP1 uniqueregion and the common VP1VP2 region of the structuralproteins These peptides were used in in vitro cytotoxicityand ex vivo stimulation assays to assess for their functionalrelevancewhileHLA restrictionswere first estimated in silicoand then experimentally confirmed A series of CD8+ T-cell

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Volume 2014

Zoology

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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Microbiology

18 ISRN Virology

epitopes could be identified nine in the NS protein and onein the VP common region Broad CD8+ T-cell responses tothese epitopes were observed in acutely infected individualsand maintained or even increased over many months afterthe resolution of acute disease Then CD8+ T cells appear toplay a prominent role in the control of B19V infection [274] Adiscrepancywas observed in persistently infected individualswhere a comparatively higher reactivity was observed againstviral capsid protein epitopes [275]

A central role of CD8+ cells was confirmed by defi-nition of the extent and phenotype of B19-specific CD8+T-cell responses during and after acute adult infectionstudied using HLA-restricted specific peptide multimericcomplexes Results indicated the presence of sustainedresponses increasing in magnitude over the first year afterinfection despite resolution of clinical symptoms and controlof viremia with T-cell populations specific for individualepitopes comprising up to 4 of CD8+ T cells These cellspossessed strong effector function and intact proliferativecapacity B19-specific cytotoxic T lymphocytes were alsodetectable in individuals tested many years after infectionat frequencies typically lower than 05 of CD8+ T-cellswhich showed a mature phenotype [276] Furthermore astrong and selective CD8+ response was seen in a group ofacutely infected patients showing HLA restriction immunedominance of a single viral epitope and focused usage of theT-cell receptor A highly focused T-cell response may aid inthe rapid identification and elimination of even low levels ofvirus and might be crucial for the effective control of viralinfection [277]

The role of T helper cells in the immune response toB19V was first investigated by using recombinant VLPscontaining the two structural proteins VP1 and VP2 (VP12capsids) or VP2 alone (VP2 capsids) and additionally theVP1u region expressed in a prokaryotic system The abilityof these antigens to stimulate Th cells to proliferate andto secrete IFN-120574 and IL-10 was measured in recently andremotely B19V-infected subjects Similar proliferation IFN-120574 and IL-10 responses were found with the VP12 and VP2capsid antigens B19-specific IFN-120574 responses were generallystronger than IL-10 responses in both recent and remoteinfection patients with relapsed or persisting symptomsshowed strikingly lower IL-10 responses VP1u-specific IFN-120574 responses were very strong among the recently infectedsubjects but absent among the remotely infected subjects afinding contrasting with the documented persistence of anti-VP1u antibodies [278 279]

Overlapping peptides and IFN-120574 immunospot assayswere also used to investigate the magnitude and extent ofthe CD4+ T-cell response to the capsid proteins Againresponses in acutely infected individuals were comparedto those in remotely infected individuals Acutely infectedindividuals were found to make broad CD4+ responses toseveral peptide pools with the strongest responses towardpeptides from the VP common region and a decrease inmagnitude correlating with the time postacute infection Byin vitro stimulation assays an ample CD4+ specific responsewas also detected in the remotely infected individuals inthis case putting in evidence a single dominant epitope in

the VP common region Phenotypic analysis of the B19-specific CD4+ cells indicated that CD4 cells were mainlyof the central memory phenotype thus diverging from theevolution seen in CD8 cells This difference may also berelevant to the definition of the pathogenetic mechanisms ofB19V infection so that activation of CD4 cells in the acutephase however functional to the development of antibodiesmay also contribute to the clinical manifestations or evento the development of immunopathological or autoimmuneprocesses while development of a CD8 immune responsewould on the other hand limit viral replication thereforereducing CD4 activation and eventually contribute to thecontrol of viral persistence [280]

Characterization of the proinflammatory and T helper(Th)1Th2 cytokine responses during acute infection or per-sistent infection was then carried out in acutely and persis-tently infected subjects An initial peak of proinflammatorycytokines (IL-1120573 TNF-120572 IL-6 and IL-8) was found at onsetof acute B19 infection Induction of theTh1 type of cytokinesIL-2 IL-12 and IL-15 was already seen in the early phase andwas sustained in many patients during the follow-up periodIn contrast cytokines associated with a Th2 type of immuneresponse (IL-4 IL-5 and IL-10) as well as an IFN-120574 responseremained low during the observation time Despite the lackof Th2 cytokines the patients developed normal B19-specificIgG levels so antibodies may have been induced by a low-grade IL-6 response as well as other cytokines for exampleTGF-120573 [281]

On the whole the B19V specific T-cell responses arepeculiar combining characteristics typical of viruses capableof lytic infections aswell as capable of establishing a persistentinfection with the requirement for a continuous surveillanceby the immune system This concept strengthens our view ofB19V as a virus capable of establishing a long-term relation-ship with its host whose outcome depends on the interplayand balance between the pathogenetic potential of the virusand the controlmechanisms operated by the immune systemFinally the dissection of the immune response with its HLArestriction TCR selection and epitope-specific recognitiondefinition of the different phenotypes and activation profilesof the cells involved will be crucial not only to our knowledgeof the course of infection but also for development of thera-peutic and prophylactic options such as the development ofa B19V vaccine

7 Epidemiology and Transmission

Parvovirus B19 is a human pathogenic virus widely andworldwide diffuse in the population Epidemiology basedon seroprevalence studies indicates that the virus is activelycirculating in all areas of the world albeit with some regionaldifferences Complementary information on virus prevalencecomes from screening on blood donors by means of nucleicacid detection techniques

A comprehensive study was conducted on seroprevalencein five different European countries in a five-year timeframe [282] In this study definition of seroprevalence inthe different class ages allowed for analysis of the force

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

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Signal TransductionJournal of

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Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

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Hindawi Publishing Corporationhttpwwwhindawicom

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 19

of infection and when considering demographic data ofthe different countries led to an estimate of the risk ofacquiring infection per class age This model assumed thelifelong persistence of antibodies as a correlatewith protectiveimmunity but it can be further refined by considering amorecomplex pattern of serological response to virus assumingthat protective immunity determined by antibody presencecan wane and allow reinfections [283] This pattern fits wellto experimental data and can be representative of the mosttemperate areas in the world Within this general patternregional differences may occur with some geographic areasreporting lower seroprevalence In addition areas of verylow seroprevalence have been reported in cases of isolatedcommunities but in these cases periodical epidemics mayraise these values abruptly The three genotypes constitute asingle serotype so epidemiology usually cannot distinguishareas with different circulation of genotypes [39] Howeverin western Africa where genotype 3 is most prevalent aconfounding effect with respect to a clear separation ofnonreactive to reactive populations has been attributed theprevalent circulation of genotype 3 [284]

Data on the prevalence of infection in the general adultpopulation also come from surveys on blood donors bymeans of nucleic acid detection techniques [285] Datahave accumulated in the years reporting values differingwidely in dependence of the sensitivity of the techniqueused and the epidemiological context [286] More recentdata on large populations over several years obtained bysensitive quantitative PCR techniques indicate prevalencerates in the range 1ndash001 of viremic donors [24 287ndash291] with higher frequencies to be expected in the youngerage groups and in epidemic periods The more recentlydeveloped molecular techniques ensure the detection of allgenotypes also allowing for their discrimination [292 293]Theprevalent genotype is genotype 1 that accounts for almostthe totality of circulating virus in temperate areas Genotype 3is prevalent inwesternAfrica but is now increasingly reportedin many areas of the world Genotype 2 is considered anancient genotype frequently detected as persistent in tissuesof elder individuals but very rarely detected as circulatingvirus

The main route of transmission of the virus is therespiratory route The virus can be detected in the saliva inthe acute phase of infection and has been experimentallytransmitted via nasal inoculation Circulation of the virusis higher in the springearly summer and epidemic cyclesare reported to occur every 4-5 years Close contacts suchin households or schools favor transmission with attackrates as high as 50 [180] A concern arises with respect totransmission in hospitals when staff or susceptible patientscan be exposed to source-infected individuals [294 295]Due to the viremic phase in the course of infection thevirus can be present in blood at high titers then posing arisk of iatrogenic transmission of the virus via blood bloodcomponents and blood products [286]

As discussed the virus can be transmitted transplacen-tally from mother to fetus then B19V should always beincluded in the assessment of risk of fetal infections Anoverall assessment first needs to evaluate the risk of acquiring

infection by pregnant women by considering the fraction ofthe susceptible population and its distribution per class agesthe force of infection for the respective ages the demographiccurve and relative distribution of pregnancies [282] Thenan estimated rate of transmission of the virus to fetus hasbeen reported varying in the range 25ndash50 while an overallrisk of fetal death has been reported to be lower than 10[234 296] Although approximate these calculationswill leadto an overall estimate of the total number of fetal lossesdue to B19V infection in a given epidemiological settingnecessarily taking into account variations due to geographicaland temporal fluctuations

Several studies have been carried out to obtain an experi-mental evaluation of the impact of B19V infection on prenatalpathologies although with discordant results [297ndash301] Amajor problem arises with the heterogeneity of the diagnosticprocedures employed by different groups and therefore ofthe criteria used to include subjects in the study groupsInclusion criteria have been chosen depending on maternalsymptoms known risk of exposure or fetal abnormalitiesor postmortem analysis in cases of fetal deaths Diagnosticmethods have used a wide combination of immunologicaland direct molecular detection methods Most studies havebeen performedby retrospective collection of data while onlya few have been based on prospective evaluation of popu-lation cohorts Large population-based studies to determinethe burden of prenatal infections have been carried out ina few settings [302ndash305] In these cases the incidence ofreported cases of B19V infection has usually been exceedinglylowWhile possibly reflecting true epidemiological situationsthese results should be considered indicative of a lowerestimate due to inherent limits in inclusion and diagnosticcriteria

8 Diagnosis of Infection

81 Analytical Profile A clinical diagnosis of B19V infectionscan only be suspected Infections can be asymptomatic orpresent with unspecific symptoms while the typical symp-toms attributed to B19 infection can be the results of otherinfections Then a laboratory diagnosis is required in thepresence of a specific or generic request

The fact that the virus is not adapted to grow in cellcultures promoted from the very beginning the developmentof direct molecular methods for the detection of B19V inclinical specimens The diagnostic approach can now relyon the detection of specific viral components viral genomeor proteins that is a complement to the more traditionalapproach to the detection of a specific immune responsemainly antibodies of IgM and IgG classes Serum or plasmaspecimens are the material of choice for the detection in thesame sample of specific antibodies and viral DNA in theviremic phase Viral DNA or proteins can be detected alsofrom bone marrow aspirates or bioptic samples In case ofsuspected fetal infections amniotic fluid is suitable for thedetection of viral DNA while in case of fetal death analysis offetal or placental tissues may allow to indicate viral etiology[306]

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

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Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

20 ISRN Virology

As discussed B19V is a virus capable of infections pre-senting with different courses so that the acute-phase infec-tion can be followed by a delayed clearance active chronicinfections or silent persistence in tissues depending on theinterplay with host factors and the efficacy of the immunesystem response Therefore an accurate laboratory diagnosisof B19V infection will necessary rely on a multiparametricapproach combining as much as possible both moleculardetection of viral components and immunological detectionof virus-specific antibodies [307]

82 Molecular Methods The detection of the viral genome inperipheral blood bone marrow or tissues can be consideredthe more direct and appropriate approach to the diagnosis ofinfection Since the beginning the technical advancementsin the development of molecular analytic techniques havealways found a complete paradigm in the development ofapplications to the detection of B19V

In the progress towards a rapid and accurate moleculardiagnosis a wide array of molecular hybridization and ofdifferent nucleic acid amplification techniques have contin-uously been developed [308ndash314] In particular standardiza-tion and inclusion of competitor or internal controls [315ndash317] have been developed for PCR protocols in a continu-ous effort of accuracy and robustness Nowadays real-timequantitative internally controlled PCR techniques must beconsidered the standard analytical method for the moleculardetection of B19V [318ndash321] Two main requirements shouldbe met first the capability of detection of all genotypesof B19V then a calibrated and standardized quantifica-tion of viral target Both of these requirements can takeadvantage of international standards and can be challengedby international proficiency panels [293] The continuoustechnical development will certainly lead in the future tonovel molecular detection methods and analytical platformsto improve performances and reduce time and costs

Finally in situ hybridization techniques for the detectionof viral nucleic acids [322ndash327] and immunohistochemicaldetection of viral proteins [328 329] can be useful as acomplement to PCR techniques for investigation of viralinfection in bioptic samples with the advantage of the iden-tification of target infected cells and allowing discriminationof productive infections from silent persistence of virus

83 Immunological Methods Detection of a specific immuneresponse is still considered the standard and most widelyusedmeans of laboratory diagnosis of B19V infection Paralleldetection of specific anti-B19 IgM and IgG antibodies iscarried out and interpretation of the combination of resultsmay allow for a presumptive diagnosis of active recent orpast infection

Historically at the beginning of the studies on B19Vimmunological assays were established using native virusas antigens [330 331] but very early on this limitation wasovercome and the antigens used for immunological detectionhave been obtained by means of heterologous recombi-nant expression systems Recombinant proteins expressed inprokaryotic systems usually lose their native conformation

and have been used as suitable for the detection of immunityagainst linear epitopes while recombinant proteins expressedin eukaryotic system can maintain native conformation andcan be used to detect immunity against conformationalepitopes In particular viral capsid proteins assemble as VLPswith antigenic configuration quite similar to that on nativevirus and are the recognized standard for immunologicaldetection

Enzyme immunoassays or recently developed chemilu-minescent immunoassays can use VLPs composed of VP2only or VP2+VP1 or VP2+VP1u expressed in prokaryoticsystems to allow detection of antibodies to conformationalVP2 or also VP1u linear epitopes Western blot or better lineblot assays will include an array of conformational and linearantigens and can be used as a confirmatory assay to dissect therange of antibody response to B19V [332 333] In this kind ofassay also NS can be used as antigen to detect the presence ofspecific antibodies whose correlation with clinical course ishowever still controversial Of limited availability althoughpotentially useful are assays to determine IgG avidity oracute-phase ETS reactivity [334 335]

9 Prophylactic and Therapeutic Options

B19V infection is normally considered a benign clinicalsituation The virus is widely diffuse and in most casesinfection is asymptomatic or unnoticed with an uneventfulclinical course This situation of course does not accountfor the totality of cases Hematological consequences can berelevant in patients with underlying hematological disordersor in patients with immune system deficits and the ery-throid aplasia can be severe and require transfusion therapyIn otherwise healthy subjects the development of chronicinflammatory and rheumatic manifestations can be severelyimpairingThe risk of infection in pregnancy with its possibleconsequences on the fetus is of major concern

Therefore not only a prompt and accurate diagnosisof infection is required but a comprehensive approachincluding prophylactic therapeutic and monitoring actionsshould be considered Specific actions would include mea-sures for reducing transmission of virus through blood andblood-derived products use of passive immunization as atherapeutic intervention and finally the development of avaccine and specific antiviral drugs

91 Screening and Blood Productsrsquo Safety The presence inthe course of infection of a high-titer early viremic phase inabsence of specific symptoms as well as the delayed clearanceof virus from bloodstream and possible occurrence of low-titer chronic infections may pose a question regarding therisk of transmission of virus through use of blood bloodcomponents or blood products Twomajor factors play a rolein determining the clinical outcome of parenteral exposureto the virus the total amount of virus transfused or infusedto recipients and the immune status and competence of thepatients

Regarding the first issue some studies indicate pos-sible viral concentration levels necessary for transmission

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

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[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

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International Journal of

Volume 2014

Zoology

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Molecular Biology International

GenomicsInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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BioinformaticsAdvances in

Marine BiologyJournal of

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Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 21

of infection In the absence of specific Ig in both donorand recipient a threshold level of about 107 InternationalUnits (IU) per mL seems necessary to obtain infectionas determined by seroconversion and viremia in recipients[285] The presence of specific antibodies in the donatedblood interferes with infectivity and the presence of previousimmunity in recipients seems to be protective Given boththe reported frequencies of high-titer viremic blood unitsand seroprevalence rates in the population the probability ofinfection by exposure to single blood or blood componentsunits is low [336 337] Very few case reports describesymptomatic infections while linked donor-recipient stud-ies indicate that this situation is infrequent and in mostcases clinically irrelevant [338] Single-donor screenings aretherefore unjustified in terms of costs however high-riskpatients with hematological disorders immune deficienciesor pregnant women would benefit from the availability ofdedicated donations proven to be free from B19V

A completely different situation is present for blood prod-ucts that are manufactured from large pools of donationsIn these cases inclusion of high-titer viremic units in themanufacturing pools can be expected with high probabilityand dilution during the manufacturing process may not besufficient to fall below a safety threshold level In fact B19VDNA could be detected at high frequencies in most blood-derived products before introduction of screening and mea-sures to exclude contaminated donations High rates of trans-mission of infection as inferred from higher seroprevalenceor viremia rates were detected in at-risk recipients groupsmainly hemophiliac andor immunodeficient patients [339]

To reduce the risk of transmission of virus through bloodproducts and given the estimated minimal infectious doseof B19V a safety threshold has been indicated by regulatoryoffices at 104 IUmL Quantitative molecular detection meth-ods accurately calibrated and able to detect all genotypesare or should now be used to detect above-threshold con-tamination of manufacturing pools trace and withdraw thecontaminating donations in an effort to implement bloodproducts safety In the manufacturing process removal orinactivation steps are normally introduced to reduce the riskof transmission of undetected viruses B19V is a small virusresistant to solventdetergent treatments but only relativelyresistant to heat treatment in particular B19V suscepti-bility to heat inactivation is dependent upon the physicalconditions and composition of medium Heat inactivationchemical inactivation or physical removal of virus should allbe considered in the production steps to further increase thesafety of blood and blood-derived products [286]

92 Therapeutic Intervention Therapeutic options for B19Vare limited Only rarely acute-phase symptomatology mayrequire symptomatic treatments Transfusions are requiredto treat the anemia in cases of transient aplastic crisis orprolonged anemia while in cases of arthralgias nonsteroidalanti-inflammatory drugsmay exert beneficial effects In casesof fetal infections and hydrops intrauterine transfusions areindicated when the hemoglobin concentration in the fetalcirculation falls below a threshold level and case series

report improved survival rates of hydropic fetuses [231340]

A different scenario is present in the course of chronicinfections that may depend on the inability of the immunesystem to develop an effective and neutralizing responseIn this case passive immunization can be considered as aneffective means of reducing the viral load IVIG preparationsbeing prepared from large pools of donors representing thecollective immune memory of a population usually containhigh levels of neutralizing anti-B19V antibodies and can beused with success to reduce the viral load [341] HoweverIVIG may not be normally effective in achieving a completeclearance of the virus then a beneficial effect is temporaryand wanes with decaying of exogenous antibodies so that inmany instances cycles of IVIG administrations have to berepeated [342] Usually clearance of infection occurs whenthe patientrsquos own immune systemdevelops a completematureimmune response so a complementary approach would beto relief known causes of immunodeficiency As examples incases of HIV infection HAART therapy will probably allowfor reconstitution of the immune function and cure of B19Vinfection [343] in cases of posttransplant immunosuppres-sion patients may take advantage of IVIG administrationcoupled with a change in the immunosuppressive therapeuticscheme [344]

As a final remark it should be noted that in the case ofB19V no clinical trials have been carried out to determinean optimal therapeutic scheme for the administration ofIVIG so the treatment is still empirical Also a possiblevalue of prophylactic administration of IVIG to prevent fetaltransmission has not been evaluated Human monoclonalantibodies have been developed but their therapeutic orprophylactic use has not been evaluated [345] All of theselimitations prompt for an extensive and controlled study ofthe efficacy of passive immunization therapeutic or prophy-lactic schemes

93 Vaccine Development The development of a vaccine forB19V has been a problematical endeavor In theory a vaccinewould be useful and effective as B19V is a virus adaptedexclusively to human host transmitted by direct interper-sonal contact and effectively neutralized by the immuneresponse On the other hand infection is in most casessubclinical clinical consequences are mild and self-limitingor on the opposite with a tendency to chronicization evenin the presence of immune response so the real utility of ageneral vaccine might be questioned

A rationale for the development and introduction ofa vaccine would mainly be to protect at-risk populationssuch as patients with underlying hematological disorders Inparticular women of childbearing age would have benefitsfrom vaccine protection chiefly in terms of fetal safety Inthis case vaccination would reduce the needs for screeningsurveillance and followup and would avoid a small butdefinite number of fetal losses

Preliminary work on vaccine development has beenconducted Main immunogenic determinants are consideredthe viral capsid proteins with their VP2 conformational

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

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Nucleic AcidsJournal of

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

22 ISRN Virology

and VP1u linear epitopes Viral capsid proteins expressed ineukaryotic heterologous systems will retain original structureand formVLPs that are antigenically similar to native virionsTherefore for vaccine VLPs can be produced and assembledby VP2 protein only or can be enriched in VP1 to includeneutralizing epitopes encoded in the VP1u region [346]These VLPs are immunogenic in the animal experimentalmodel Phase I studies showed their immunogenicity andrelative safety in humans [347] however phase II studiesshowed a remarkable reactogenicity [348] These results stillprompt for the development of efficient and safer vaccines

94 Antiviral Drugs Development No antiviral therapy hasbeen developed or evaluated for B19V A rationale for thedevelopment of a specific antiviral therapy would be inthe treatment of chronic infections in immunosuppressedpatients or for reducing the inflammatory aspects of acuteor chronic infections or possibly for prophylaxis in selectedcases Although the virus and the virus-cell systempotentiallyoffer several targets for an antiviral therapy no studies haveyet been reported in this field Viral NS protein or thephospholipase domain in the VP1u region are both requiredfor viral infectivity and responsible of pathogenetic effects sothey constitute potentially relevant targets Specific inhibitionof their activity would probably impair the capacity of thevirus to replicate as well as the cytotoxicity and proinflamma-tory activity of the virusThe development of pharmaceuticalbiotechnology tools and of accurate quantitative methods toevaluate reduction in viral infectivity will be required to leadresearch in this field

10 Conclusions

As a final comment to this review B19V is a virus that canoffer continuous matter of interest to virologists for manyreasons The pattern of genetic evolution its peculiar prop-erties and functional profile the characteristics of its narrowtropism and restricted replication its complex relationshipwith the host and its ample pathogenetic potential are alltopics that are far from a comprehensive understandingThe lack of efficient adaptation to in vitro cellular culturesand the absence of animal models have limited classicalvirological studies and made studies on B19V dependenton molecular biology In this case too the difficulties inobtaining efficient recombinant systems have impaired athorough understanding of the viral lifecycle and virus-hostinteractions

B19V is also underestimated from a clinical perspectiveIts wide circulation and prevalent benign and self-limitingclinical course generally lead to a diminished appreciationof its pathogenetic potential In this review only selectedclinical aspects have been discussed but B19V is a possibleetiological agent in a wider ensemble of diseases encompass-ing practically all organs and systems An extended awarenessand definition of the actual pathogenetic role of B19V inthe human diseases the development of better diagnosticmethods and algorithms the development of prophylacticand therapeutic options will continue to be relevant issuesworth of efforts by the scientific community

References

[1] A King E Lefkowitz M Adams and E Carstens Eds NinthReport of the International Committee on Taxonomy of VirusesElsevier New York NY USA 2011

[2] Y E Cossart AM Field B Cant andDWiddows ldquoParvoviruslike particles in human serardquoTheLancet vol 1 no 7898 pp 72ndash73 1975

[3] J Summers S E Jones and M J Anderson ldquoCharacterizationof the genome of the agent of erythrocyte aplasia permitsits classification as a human parvovirusrdquo Journal of GeneralVirology vol 64 no 11 pp 2527ndash2532 1983

[4] J P Clewley ldquoBiochemical characterization of a human par-vovirusrdquo Journal of General Virology vol 65 no 1 pp 241ndash2451984

[5] S F Cotmore and P Tattersall ldquoCharacterization andmolecularcloning of a human parvovirus genomerdquo Science vol 226 no4679 pp 1161ndash1165 1984

[6] R O Shade M C Blundell S F Cotmore P Tattersall andC R Astell ldquoNucleotide sequence and genome organization ofhuman parvovirus B19 isolated from the serumof a child duringaplastic crisisrdquo Journal of Virology vol 58 no 3 pp 921ndash9361986

[7] V Deiss J D Tratschin M Weitz and G Siegl ldquoCloning ofthe human parvovirus B19 genome and structural analysis ofits palindromic terminirdquo Virology vol 175 no 1 pp 247ndash2541990

[8] G Zuccheri A BergiaGGallinellaMMusiani andB SamorıldquoScanning force microscopy study on a single-stranded DNAthe genome of parvovirus B19rdquo ChemBioChem vol 2 no 3 pp199ndash204 2001

[9] S F Cotmore V C McKie and L J Anderson ldquoIdentificationof the major structural and nonstructural proteins encodedby human parvovirus B19 and mapping of their genes byprocaryotic expression of isolated genomic fragmentsrdquo Journalof Virology vol 60 no 2 pp 548ndash557 1986

[10] M S Chapman andMG Rossmann ldquoStructure sequence andfunction correlations among parvovirusesrdquo Virology vol 194no 2 pp 491ndash508 1993

[11] M Agbandje R McKenna M G Rossmann S Kajigaya andN S Young ldquoPreliminary X-ray crystallographic investigationof human parvovirus B19rdquo Virology vol 184 no 1 pp 170ndash1741991

[12] M Agbandje S Kajigaya R MoKenna N S Young and MG Rossmann ldquoThe structure of human parvovirus B19 at 8 Aresolutionrdquo Virology vol 203 no 1 pp 106ndash115 1994

[13] B Kaufmann A A Simpson and M G Rossmann ldquoThestructure of human parvovirus B19rdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 101 no32 pp 11628ndash11633 2004

[14] B Kaufmann P R Chipman V A Kostyuchenko S Modrowand M G Rossmann ldquoVisualization of the externalized VP2N termini of infectious human parvovirus B19rdquo Journal ofVirology vol 82 no 15 pp 7306ndash7312 2008

[15] Z Zadori J Szelei M C Lacoste et al ldquoA viral phospholipaseA2 is required for parvovirus infectivityrdquo Developmental Cellvol 1 no 2 pp 291ndash302 2001

[16] S Canaan Z Zadori F Ghomashchi et al ldquoInterfacial enzy-mology of parvovirus phospholipases A2rdquo Journal of BiologicalChemistry vol 279 no 15 pp 14502ndash14508 2004

[17] G Gallinella S Venturoli E Manaresi M Musiani and MZerbini ldquoB19 virus genome diversity epidemiological and

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 23

clinical correlationsrdquo Journal of Clinical Virology vol 28 no 1pp 1ndash13 2003

[18] Q T Nguyen C Sifer V Schneider et al ldquoNovel humanerythrovirus associated with transient aplastic anemiardquo Journalof Clinical Microbiology vol 37 no 8 pp 2483ndash2487 1999

[19] K Hokynar M Soderlund-Venermo M Pesonen et al ldquoA newparvovirus genotype persistent in human skinrdquo Virology vol302 no 2 pp 224ndash228 2002

[20] Q T Nguyen S Wong E D Heegaard and K E BrownldquoIdentification and characterization of a second novel humanErythrovirus variant A6rdquo Virology vol 301 no 2 pp 374ndash3802002

[21] A Servant S Laperche F Lallemand et al ldquoGenetic diversitywithin human erythroviruses identification of three geno-typesrdquo Journal of Virology vol 76 no 18 pp 9124ndash9134 2002

[22] N L Toan A Duechting P G Kremsner et al ldquoPhylogeneticanalysis of human parvovirus B19 indicating two subgroups ofgenotype 1 in Vietnamese patientsrdquo Journal of General Virologyvol 87 no 10 pp 2941ndash2949 2006

[23] A Parsyan C Szmaragd J P Allain and D Candotti ldquoIden-tification and genetic diversity of two human parvovirus B19genotype 3 subtypesrdquo Journal of General Virology vol 88 no2 pp 428ndash431 2007

[24] D Candotti N Etiz A Parsyan and J P Allain ldquoIdentificationand characterization of persistent human erythrovirus infectionin blood donor samplesrdquo Journal of Virology vol 78 no 22 pp12169ndash12178 2004

[25] S Sanabani W K Neto J Pereira and E C Sabino ldquoSequencevariability of human erythroviruses present in bone marrow ofBrazilian patients with various parvovirus B19-related hemato-logical symptomsrdquo Journal of Clinical Microbiology vol 44 no2 pp 604ndash606 2006

[26] R B Freitas F L Melo D S Oliveira et al ldquoMolecularcharacterization of human erythrovirus B19 strains obtainedfrom patients with several clinical presentations in the Amazonregion of Brazilrdquo Journal of Clinical Virology vol 43 no 1 pp60ndash65 2008

[27] J M Hubschen Z Mihneva A F Mentis et al ldquoPhylogeneticanalysis of human parvovirus B19 sequences from elevendifferent countries confirms the predominance of genotype 1and suggests the spread of genotype 3brdquo Journal of ClinicalMicrobiology vol 47 no 11 pp 3735ndash3738 2009

[28] CCorcoranDHardie J Yeats andH Smuts ldquoGenetic variantsof human parvovirus B19 in South Africa cocirculation of threegenotypes and identification of a novel subtype of genotype 1rdquoJournal of Clinical Microbiology vol 48 no 1 pp 137ndash142 2010

[29] L Liefeldt A Plentz B Klempa et al ldquoRecurrent high levelparvovirus B19genotype 2 viremia in a renal transplant recip-ient analyzed by real-time PCR for simultaneous detection ofgenotypes 1 to 3rdquo Journal of Medical Virology vol 75 no 1 pp161ndash169 2005

[30] B J Cohen J Gandhi and J P Clewley ldquoGenetic variants ofparvovirus B19 identified in the United Kingdom implicationsfor diagnostic testingrdquo Journal of Clinical Virology vol 36 no2 pp 152ndash155 2006

[31] P Grabarczyk A Kalinska M Kara et al ldquoIdentification andcharacterization of acute infection with parvovirus B19 geno-type 2 in immunocompromised patients in Polandrdquo Journal ofMedical Virology vol 83 pp 142ndash149 2011

[32] P Norja K Hokynar L M Aaltonen et al ldquoBioportfoliolifelong persistence of variant and prototypic erythrovirus DNA

genomes in human tissuerdquo Proceedings of the National Academyof Sciences of the United States of America vol 103 no 19 pp7450ndash7453 2006

[33] B Schneider A Hone R H Tolba H P Fischer J Blumeland A M Eis-Hubinger ldquoSimultaneous persistence of multiplegenome variants of human parvovirus B19rdquo Journal of GeneralVirology vol 89 no 1 pp 164ndash176 2008

[34] F Corcioli K Zakrzewska A Rinieri et al ldquoTissue persistenceof parvovirus B19 genotypes in asymptomatic personsrdquo Journalof Medical Virology vol 80 no 11 pp 2005ndash2011 2008

[35] L A Shackelton and E C Holmes ldquoPhylogenetic evidencefor the rapid evolution of human B19 erythrovirusrdquo Journal ofVirology vol 80 no 7 pp 3666ndash3669 2006

[36] P Norja A M Eis-Hubinger M Soderlund-Venermo KHedman and P Simmonds ldquoRapid sequence change andgeographical spread of human parvovirus B19 comparison ofB19 virus evolution in acute and persistent infectionsrdquo Journalof Virology vol 82 no 13 pp 6427ndash6433 2008

[37] M Suzuki Y Yoto A Ishikawa and H Tsutsumi ldquoAnalysis ofnucleotide sequences of human parvovirus B19 genome revealstwo different modes of evolution a gradual alteration and asudden replacement a retrospective study in Sapporo Japanfrom 1980 to 2008rdquo Journal of Virology vol 83 no 21 pp 10975ndash10980 2009

[38] MWMolenaar-de Backer VV Lukashov R S vanBinnendijkH J Boot and H L Zaaijer ldquoGlobal co-existence of twoevolutionary lineages of parvovirus B19 1a different in genome-wide synonymous positionsrdquo PLoS ONE vol 7 Article IDe43206 2012

[39] A Ekman K Hokynar L Kakkola et al ldquoBiological andimmunological relations among human parvovirus B19 geno-types 1 to 3rdquo Journal of Virology vol 81 no 13 pp 6927ndash69352007

[40] P P Mortimer R K Humphries and J G Moore ldquoA humanparvovirus-like virus inhibits haematopoietic colony formationin vitrordquo Nature vol 302 no 5907 pp 426ndash429 1983

[41] N S Young P P Mortimer J G Moore and R K HumphriesldquoCharacterization of a virus that causes transient aplastic crisisrdquoJournal of Clinical Investigation vol 73 no 1 pp 224ndash230 1984

[42] N Young M Harrison and J Moore ldquoDirect demonstration ofthe human parvovirus in erythroid progenitor cells infected invitrordquo Journal of Clinical Investigation vol 74 no 6 pp 2024ndash2032 1984

[43] K Ozawa G Kurtzman and N Young ldquoReplication of the B19parvovirus in human bone marrow cell culturesrdquo Science vol233 no 4766 pp 883ndash886 1986

[44] KOzawaGKurtzman andNYoung ldquoProductive infection byB19 parvovirus of human erythroid bone marrow cells in vitrordquoBlood vol 70 no 2 pp 384ndash391 1987

[45] A Srivastava and L Lu ldquoReplication of B19 parvovirus in highlyenriched hematopoietic progenitor cells from normal humanbone marrowrdquo Journal of Virology vol 62 no 8 pp 3059ndash30631988

[46] T F Schwarz S Serke B Hottentrager et al ldquoReplication ofparvovirus B19 in hematopoietic progenitor cells generated invitro fromnormal humanperipheral bloodrdquo Journal of Virologyvol 66 no 2 pp 1273ndash1276 1992

[47] A Hemauer A Gigler R Gareus A Reichle H Wolf andS Modrow ldquoInfection of apheresis cells by parvovirus B19rdquoJournal of General Virology vol 80 no 3 pp 627ndash630 1999

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

24 ISRN Virology

[48] K E Brown J Mori B J Cohen and A M Field ldquoIn vitropropagation of parvovirus B19 in primary foetal liver culturerdquoJournal of General Virology vol 72 no 3 pp 741ndash745 1991

[49] A L Morey G Patou S Myint and K A Fleming ldquoInvitro culture for the detection of infectious human parvovirusB19 and B19-specific antibodies using foetal haematopoieticprecursor cellsrdquo Journal of General Virology vol 73 no 12 pp3313ndash3317 1992

[50] N Yaegashi H Shiraishi T TakeshitaMNakamura A Yajimaand K Sugamura ldquoPropagation of human parvovirus B19 inprimary culture of erythroid lineage cells derived from fetalliverrdquo Journal of Virology vol 63 no 6 pp 2422ndash2426 1989

[51] C E Sosa J B Mahony K E Luinstra M Sternbach andM A Chernesky ldquoReplication and cytopathology of humanparvovirus B19 in human umbilical cord blood erythroidprogenitor cellsrdquo Journal of Medical Virology vol 36 no 2 pp125ndash130 1992

[52] C H Srivastava S Zhou N C Munshi and A SrivastavaldquoParvovirus B19 replication in human umbilical cord bloodcellsrdquo Virology vol 189 no 2 pp 456ndash461 1992

[53] S Wong N Zhi C Filippone et al ldquoEx vivo-generatedCD36+ erythroid progenitors are highly permissive to humanparvovirus B19 replicationrdquo Journal of Virology vol 82 no 5pp 2470ndash2476 2008

[54] C Filippone R Franssila A Kumar et al ldquoErythroid progeni-tor cells expanded from peripheral blood without mobilizationor preselection molecular characteristics and functional com-petencerdquo PLoS ONE vol 5 no 3 Article ID e9496 2010

[55] S Shimomura N Komatsu N Frickhofen S Anderson SKajigaya and N S Young ldquoFirst continuous propagation of B19parvovirus in a cell linerdquo Blood vol 79 no 1 pp 18ndash24 1992

[56] E Miyagawa T Yoshida H Takahashi et al ldquoInfection ofthe erythroid cell line KU812Ep6 with human parvovirus B19and its application to titration of B19 infectivityrdquo Journal ofVirological Methods vol 83 no 1-2 pp 45ndash54 1999

[57] S Wong and K E Brown ldquoDevelopment of an improvedmethod of detection of infectious parvovirus B19rdquo Journal ofClinical Virology vol 35 no 4 pp 407ndash413 2006

[58] C H Srivastava R J Samulski L Lu S H Larsen and ASrivastava ldquoConstruction of a recombinant human parvovirusB19 adeno-associated virus 2 (AAV) DNA inverted terminalrepeats are functional in aAAV-B19 hybrid virusrdquoProceedings ofthe National Academy of Sciences of the United States of Americavol 86 no 20 pp 8078ndash8082 1989

[59] S Ponnazhagan K A Weigel S P Raikwar P Mukherjee MC Yoder and A Srivastava ldquoRecombinant human parvovirusB19 vectors erythroid cell-specific delivery and expression oftransduced genesrdquo Journal of Virology vol 72 no 6 pp 5224ndash5230 1998

[60] N Zhi Z Zadori K E Brown and P Tijssen ldquoConstructionand sequencing of an infectious clone of the human parvovirusB19rdquo Virology vol 318 no 1 pp 142ndash152 2004

[61] C Filippone N Zhi S Wong et al ldquoVP1u phospholipaseactivity is critical for infectivity of full-length parvovirus B19genomic clonesrdquo Virology vol 374 no 2 pp 444ndash452 2008

[62] N Zhi I P Mills J Lu S Wong C Filippone and K E BrownldquoMolecular and functional analyses of a human parvovirus B19infectious clone demonstrates essential roles for NS1 VP1 andthe 11-kilodalton protein in virus replication and infectivityrdquoJournal of Virology vol 80 no 12 pp 5941ndash5950 2006

[63] K E Brown and B J Cohen ldquoHaemagglutination by parvovirusB19rdquo Journal of General Virology vol 73 no 8 pp 2147ndash21491992

[64] K E Brown S M Anderson and N S Young ldquoErythrocyte Pantigen cellular receptor for B19 parvovirusrdquo Science vol 262no 5130 pp 114ndash117 1993

[65] K E Brown J R Hibbs G Gallinella et al ldquoResistanceto parvovirus B19 infection due to lack of virus receptor(erythrocyte P antigen)rdquoThe New England Journal of Medicinevol 330 no 17 pp 1192ndash1196 1994

[66] K A Weigel-Kelley M C Yoder and A Srivastava ldquoRecom-binant human parvovirus B19 vectors erythrocyte P antigenis necessary but not sufficient for successful transduction ofhuman hematopoietic cellsrdquo Journal of Virology vol 75 no 9pp 4110ndash4116 2001

[67] K A Weigel-Kelley M C Yoder and A Srivastava ldquo12057251205731integrin as a cellular coreceptor for human parvovirus B19requirement of functional activation of 1205731 integrin for viralentryrdquo Blood vol 102 no 12 pp 3927ndash3933 2003

[68] K A Weigel-Kelley M C Yoder L Chen and A SrivastavaldquoRole of integrin cross-regulation in parvovirus B19 targetingrdquoHuman Gene Therapy vol 17 no 9 pp 909ndash920 2006

[69] K A K Weigel-Van Aken ldquoPharmacological activation ofguanine nucleotide exchange factors for the small GTPase Rap1recruits high-affinity 1205731 integrins as coreceptors for parvovirusB19 improved ex vivo gene transfer to human erythroidprogenitor cellsrdquoHumanGeneTherapy vol 20 no 12 pp 1665ndash1678 2009

[70] L L W Cooling T A W Koerner and S J Naides ldquoMultipleglycosphingolipids determine the tissue tropism of parvovirusB19rdquo Journal of Infectious Diseases vol 172 no 5 pp 1198ndash12051995

[71] Y Munakata T Saito-Ito K Kumura-Ishii et al ldquoKu80autoantigen as a cellular coreceptor for human parvovirus B19infectionrdquo Blood vol 106 no 10 pp 3449ndash3456 2005

[72] P R ChipmanM Agbandje-Mckenna S Kajigaya et al ldquoCryo-electron microscopy studies of empty capsids of human par-vovirus B19 complexed with its cellular receptorrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 93 no 15 pp 7502ndash7506 1996

[73] B Kaufmann U Baxa P R Chipman M G Rossmann SModrow and R Seckler ldquoParvovirus B19 does not bind tomembrane-associated globoside in vitrordquo Virology vol 332 no1 pp 189ndash198 2005

[74] C Ros M Gerber and C Kempf ldquoConformational changes inthe VP1-unique region of native human parvovirus B19 leadto exposure of internal sequences that play a role in virusneutralization and infectivityrdquo Journal of Virology vol 80 no24 pp 12017ndash12024 2006

[75] C Bonsch C Kempf and C Ros ldquoInteraction of parvovirusB19 with human erythrocytes alters virus structure and cellmembrane integrityrdquo Journal of Virology vol 82 no 23 pp11784ndash11791 2008

[76] C Bonsch C Zuercher P Lieby C Kempf and C Ros ldquoThegloboside receptor triggers structural changes in the B19 viruscapsid that facilitate virus internalizationrdquo Journal of Virologyvol 84 no 22 pp 11737ndash11746 2010

[77] S Quattrocchi N Ruprecht C Bonsch et al ldquoCharacterizationof the early steps of human parvovirus B19 infectionrdquo Journal ofVirology vol 86 pp 9274ndash9284 2012

[78] C Bonsch C Kempf I Mueller et al ldquoChloroquine and itsderivatives exacerbate B19V associated anemia by promoting

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 25

viral replicationrdquo PLoS Neglected Tropical Diseases vol 4 no4 2010

[79] F Bonvicini C Filippone E Manaresi M Zerbini MMusianiand G Gallinella ldquoHepG2 hepatocellular carcinoma cells area non-permissive system for B19 virus infectionrdquo Journal ofGeneral Virology vol 89 no 12 pp 3034ndash3038 2008

[80] S Dorsch G Liebisch B Kaufmann et al ldquoThe VP1 uniqueregion of parvovirus B19 and its constituent phospholipase A2-like activityrdquo Journal of Virology vol 76 no 4 pp 2014ndash20182002

[81] G Gallinella E Manaresi E Zuffi et al ldquoDifferent patternsof restriction to B19 parvovirus replication in human blast celllinesrdquo Virology vol 278 no 2 pp 361ndash367 2000

[82] W Guan S Wong N Zhi and J Qiu ldquoThe genome of humanparvovirus B19 can replicate in nonpermissive cells with thehelp of adenovirus genes and produces infectious virusrdquo Journalof Virology vol 83 no 18 pp 9541ndash9553 2009

[83] MC Blundell C Beard andC RAstell ldquoIn vitro identificationof a B19 parvovirus promoterrdquo Virology vol 157 no 2 pp 534ndash538 1987

[84] C Doerig P Beard and B Hirt ldquoA transcriptional promoter ofthe human parvovirus B19 active in vitro and in vivordquo Virologyvol 157 no 2 pp 539ndash542 1987

[85] M C Blundell and C R Astell ldquoA GC-box motif upstream ofthe B19 parvovirus unique promoter is important for in vitrotranscriptionrdquo Journal of Virology vol 63 no 11 pp 4814ndash48231989

[86] C Doerig B Hirt J P Antonietti and P Beard ldquoNonstructuralprotein of parvoviruses B19 and minute virus of mice controlstranscriptionrdquo Journal of Virology vol 64 no 1 pp 387ndash3961990

[87] J M Liu H Fujii S W Green N Komatsu N S Young and TShimada ldquoIndiscriminate activity from the B19 parvovirus P6promoter in nonpermissive cellsrdquo Virology vol 182 no 1 pp361ndash364 1991

[88] J M Liu SW Green H Yu-Shu K TMcDonagh N S Youngand T Shimada ldquoUpstream sequences within the terminalhairpin positively regulate the P6 promoter of B19 parvovirusrdquoVirology vol 185 no 1 pp 39ndash47 1991

[89] R Gareus A Gigler A Hemauer et al ldquoCharacterization ofcis-acting and Ns1 protein-responsive ELEMENTS in the p6promoter of parvovirus B19rdquo Journal of Virology vol 72 no 1pp 609ndash616 1998

[90] MMomoedaMKawase SM Jane KMiyamuraN S Youngand S Kajigaya ldquoThe transcriptional regulator YY1 binds to the51015840-terminal region of B19 parvovirus and regulates P6 promoteractivityrdquo Journal of Virology vol 68 no 11 pp 7159ndash7168 1994

[91] I Vassias U Hazan Y Michel et al ldquoRegulation of human B19parvovirus promoter expression by hGABP (E4TF1) transcrip-tion factorrdquo Journal of Biological Chemistry vol 273 no 14 pp8287ndash8293 1998

[92] U Raab B Bauer A Gigler K Beckenlehner H Wolf andS Modrow ldquoCellular transcription factors that interact withp6 promoter elements of parvovirus B19rdquo Journal of GeneralVirology vol 82 no 6 pp 1473ndash1480 2001

[93] U Raab K Beckenlehner T Lowin H H Niller S Doyle andS Modrow ldquoNS1 protein of parvovirus B19 interacts directlywith DNA sequences of the p6 promoter and with the cellulartranscription factors Sp1Sp3rdquo Virology vol 293 no 1 pp 86ndash93 2002

[94] S Pillet N Le Guyader T Hofer et al ldquoHypoxia enhanceshuman B19 erythrovirus gene expression in primary erythroidcellsrdquo Virology vol 327 no 1 pp 1ndash7 2004

[95] K Ozawa J Ayub and H Yu-Shu ldquoNovel transcription mapfor the B19 (human) pathogenic parvovirusrdquo Journal of Virologyvol 61 no 8 pp 2395ndash2406 1987

[96] K Ozawa J Ayub and N Young ldquoFunctional mapping of thegenome of the B19 (human) parvovirus by in vitro translationafter negative hybrid selectionrdquo Journal of Virology vol 62 no7 pp 2508ndash2511 1988

[97] C Beard J St Amand J and C R Astell ldquoTransient expressionof B19 parvovirus gene products in COS-7 cells transfected withB19-SV40 hybrid vectorsrdquoVirology vol 172 no 2 pp 659ndash6641989

[98] J S Amand C Beard K Humphries and C R Astell ldquoAnalysisof splice junctions and in vitro and in vivo translation potentialof the small abundant B19 parvovirus RNAsrdquoVirology vol 183no 1 pp 133ndash142 1991

[99] W Guan F Cheng Q Huang S Kleiboeker and J QiuldquoInclusion of the central exon of parvovirus B19 precursormRNA is determined bymultiple splicing enhancers in both theexon and the downstream intronrdquo Journal of Virology vol 85no 5 pp 2463ndash2468 2011

[100] Y Yoto J Qiu and D J Pintel ldquoIdentification and character-ization of two internal cleavage and polyadenylation sites ofparvovirus B19 RNArdquo Journal of Virology vol 80 no 3 pp1604ndash1609 2006

[101] W Guan Q Huang F Cheng and J Qiu ldquoInternal polyadeny-lation of the parvovirus B19 precursor mRNA is regulated byalternative splicingrdquo Journal of Biological Chemistry vol 286no 28 pp 24793ndash24805 2011

[102] J M Liu S W Green T Shimada and N S Young ldquoA block infull-length transcript maturation in cells nonpermissive for B19parvovirusrdquo Journal of Virology vol 66 no 8 pp 4686ndash46921992

[103] W Guan F Cheng Y Yoto et al ldquoBlock to the productionof full-length B19 virus transcripts by internal polyadenylationis overcome by replication of the viral genomerdquo Journal ofVirology vol 82 no 20 pp 9951ndash9963 2008

[104] S Shimomura S Wong K E Brown N Komatsu S Kajigayaand N S Young ldquoEarly and late gene expression in UT-7 cellsinfected with B19 parvovirusrdquo Virology vol 194 no 1 pp 149ndash156 1993

[105] F Bonvicini C Filippone S Delbarba et al ldquoParvovirus B19genome as a single two-state replicative and transcriptionalunitrdquo Virology vol 347 no 2 pp 447ndash454 2006

[106] F Bonvicini C Filippone EManaresi M Zerbini MMusianiand G Gallinella ldquoFunctional analysis and quantitative deter-mination of the expression profile of human parvovirus B19rdquoVirology vol 381 no 2 pp 168ndash177 2008

[107] F Bonvicini E Manaresi F Di Furio L De Falco and GGallinella ldquoParvovirus B19DNACpGdinucleotidemethylationand epigenetic regulation of viral expressionrdquo PLoS ONE vol 7Article ID e33316 2012

[108] K Ozawa and N Young ldquoCharacterization of capsid andnoncapsid proteins of B19 parvovirus propagated in humanerythroid bone marrow cell culturesrdquo Journal of Virology vol61 no 8 pp 2627ndash2630 1987

[109] J St Amand and C R Astell ldquoIdentification and characteri-zation of a family of 11-kDa proteins encoded by the humanparvovirus B19rdquo Virology vol 192 no 1 pp 121ndash131 1993

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

26 ISRN Virology

[110] W Luo and C R Astell ldquoA novel protein encoded by smallRNAs of parvovirus B19rdquo Virology vol 195 no 2 pp 448ndash4551993

[111] K Ozawa J Ayub and N Young ldquoTranslational regulation ofB19 parvovirus capsid protein production bymultiple upstreamAUG tripletsrdquo Journal of Biological Chemistry vol 263 no 22pp 10922ndash10926 1988

[112] M Leruez C Pallier I Vassias J F Elouet P Romeo andF Morinet ldquoDifferential transcription without replication ofnon-structural and structural genes of human parvovirus B19 intheUT7EPO cell line as demonstrated by in situ hybridizationrdquoJournal of General Virology vol 75 no 6 pp 1475ndash1478 1994

[113] C Pallier A Greco J Le Junter A Saib I Vassias and FMorinet ldquoThe 3rsquo untranslated region of the B19 parvoviruscapsid protein mRNAs inhibits its own mRNA translation innonpermissive cellsrdquo Journal of Virology vol 71 no 12 pp9482ndash9489 1997

[114] N Zhi Z Wan X Liu et al ldquoCodon optimization of humanparvovirus B19 capsid genes greatly increases their expressionin nonpermissive cellsrdquo Journal of Virology vol 84 no 24 pp13059ndash13062 2010

[115] O Berillo V Khailenko A Ivashchenko L Perlmuter-Shoshany and A Bolshoy ldquomiRNA and tropism of humanparvovirus B19rdquo Computational Biology and Chemistry vol 40pp 1ndash6 2012

[116] N Sol F Morinet M Alizon and U Hazan ldquoTrans-activationof the long terminal repeat of human immunodeficiency virustype 1 by the parvovirus B19 NS1 gene productrdquo Journal ofGeneral Virology vol 74 no 9 pp 2011ndash2014 1993

[117] S Moffatt N Tanaka K Tada et al ldquoA cytotoxic nonstructuralprotein NS1 of human parvovirus B19 induces activation ofinterleukin-6 gene expressionrdquo Journal of Virology vol 70 no12 pp 8485ndash8491 1996

[118] Y Fu K K Ishii Y Munakata T Saitoh M Kaku and TSasaki ldquoRegulation of tumor necrosis factor alpha promoter byhuman parvovirus B19 NS1 through activation of AP-1 and AP-2rdquo Journal of Virology vol 76 no 11 pp 5395ndash5403 2002

[119] K Ozawa J Ayub S Kajigaya T Shimada and N Young ldquoThegene encoding the nonstructural protein of B19 (human) par-vovirus may be lethal in transfected cellsrdquo Journal of Virologyvol 62 no 8 pp 2884ndash2889 1988

[120] M Momoeda S Wong M Kawase N S Young and SKajigaya ldquoA putative nucleoside triphosphate-binding domainin the nonstructural protein of B19 parvovirus is required forcytotoxicityrdquo Journal of Virology vol 68 no 12 pp 8443ndash84461994

[121] S Moffatt N Yaegashi K Tada N Tanaka and K SugamuraldquoHuman parvovirus B19 nonstructural (NS1) protein inducesapoptosis in erythroid lineage cellsrdquo Journal of Virology vol 72no 4 pp 3018ndash3028 1998

[122] N Sol J Le Junter I Vassias et al ldquoPossible interactionsbetween the NS-1 protein and tumor necrosis factor alpha path-ways in erythroid cell apoptosis induced by human parvovirusB19rdquo Journal of Virology vol 73 no 10 pp 8762ndash8770 1999

[123] S Pillet Z Annan S Fichelson and F Morinet ldquoIdentificationof a nonconventional motif necessary for the nuclear importof the human parvovirus B19 major capsid protein (VP2)rdquoVirology vol 306 no 1 pp 25ndash32 2003

[124] S Kajigaya T Shimada S Fujita andN S Young ldquoA geneticallyengineered cell line that produces empty capsids of B19 (human)parvovirusrdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 86 no 19 pp 7601ndash7605 1989

[125] B J Cohen A M Field J Mori et al ldquoMorphology andantigenicity of recombinant B19 parvovirus capsids expressedin transfected COS-7 cellsrdquo Journal of General Virology vol 76no 5 pp 1233ndash1237 1995

[126] C S Brown M M M Salimans M H M Noteborn and HT Weiland ldquoAntigenic parvovirus B19 coat proteins VP1 andVP2 produced in large quantities in a baculovirus expressionsystemrdquo Virus Research vol 15 no 3 pp 197ndash211 1990

[127] C S Brown J W M Van Lent J M Vlak and W J M SpaanldquoAssembly of empty capsids by using baculovirus recombinantsexpressing human parvovirus B19 structural proteinsrdquo Journalof Virology vol 65 no 5 pp 2702ndash2706 1991

[128] S Kajigaya H Fujii A Field et al ldquoSelf-assembled B19parvovirus capsids produced in a baculovirus system areantigenically and immunogenically similar to native virionsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 88 no 11 pp 4646ndash4650 1991

[129] S Wong M Momoeda A Field S Kajigaya and N S YoungldquoFormation of empty B19 parvovirus capsids by the truncatedminor capsid proteinrdquo Journal of Virology vol 68 no 7 pp4690ndash4694 1994

[130] MKawaseMMomoedaN S Young and SKajigaya ldquoModesttruncation of themajor capsid protein abrogates B19 parvoviruscapsid formationrdquo Journal of Virology vol 69 no 10 pp 6567ndash6571 1995

[131] M Kawase M Momoeda N S Young and S Kajigaya ldquoMostof the VP1 unique region of B19 parvovirus is on the capsidsurfacerdquo Virology vol 211 no 2 pp 359ndash366 1995

[132] M M Y Fan L Tamburic C Shippam-Brett D B Zagrodneyand C R Astell ldquoThe small 11-kDa protein from B19 parvovirusbinds growth factor receptor-binding protein 2 in vitro in a Srchomology 3 domainligand-dependent mannerrdquo Virology vol291 no 2 pp 285ndash291 2001

[133] A Y Chen E Y Zhang W Guan et al ldquoThe small 11kDanonstructural protein of human parvovirus B19 plays a key rolein inducing apoptosis during B19 virus infection of primaryerythroid progenitor cellsrdquo Blood vol 115 no 5 pp 1070ndash10802010

[134] Y Dong Y Huang Y Wang et al ldquoThe effects of the 11 kDaprotein and the putative X protein on the p6 promoter activityof parvovirus B19 in Hela cellsrdquo Virus Genes vol 46 no 1 pp167ndash169 2012

[135] A L Morey D J P Ferguson and K A Fleming ldquoUltra-structural features of fetal erythroid precursors infected withparvovirus B19 in vitro evidence of cell death by apoptosisrdquoJournal of Pathology vol 169 no 2 pp 213ndash220 1993

[136] A Y Chen W Guan S Lou Z Liu S Kleiboeker and JQiu ldquoRole of erythropoietin receptor signaling in parvovirusB19 replication in human erythroid progenitor cellsrdquo Journal ofVirology vol 84 no 23 pp 12385ndash12396 2010

[137] A Y Chen S Kleiboeker and J Qiu ldquoProductive parvovirusB19 infection of primary human erythroid progenitor cells athypoxia is regulated by STAT5A and MEK signaling but notHIF120572rdquo PLoS Pathogens vol 7 no 6 Article ID e1002088 2011

[138] KWinter K vonKietzell R Heilbronn T Pozzuto H Fechnerand S Weger ldquoRoles of E4orf6 and VA I RNA in adenovirus-mediated stimulation of human parvovirus B19 DNA replica-tion and structural gene expressionrdquo Journal of Virology vol 86pp 5099ndash5109 2012

[139] E Morita K Tada H Chisaka et al ldquoHuman parvovirus B19induces cell cycle arrest at G

2

phase with accumulation of

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 27

mitotic cyclinsrdquo Journal of Virology vol 75 no 16 pp 7555ndash7563 2001

[140] E Morita A Nakashima H Asao H Sato and K SugamuraldquoHuman parvovirus B19 nonstructural protein (NS1) inducescell cycle arrest at G

1

phaserdquo Journal of Virology vol 77 no 5pp 2915ndash2921 2003

[141] A Nakashima E Morita S Saito and K Sugamura ldquoHumanparvovirus B19 nonstructural protein transactivates thep21WAF1 through Sp1rdquo Virology vol 329 no 2 pp 493ndash5042004

[142] Z Wan N Zhi S Wong et al ldquoHuman parvovirus B19causes cell cycle arrest of human erythroid progenitors viaderegulation of the E2F family of transcription factorsrdquo Journalof Clinical Investigation vol 120 no 10 pp 3530ndash3544 2010

[143] Y Luo S Lou X Deng et al ldquoParvovirus B19 infection ofhuman primary erythroid progenitor cells triggers ATR-Chk1signaling which promotes B19 virus replicationrdquo Journal ofVirology vol 85 no 16 pp 8046ndash8055 2011

[144] S Lou Y Luo F Cheng et al ldquoHuman parvovirus B19 DNAreplication induces a DNA damage response that is dispensablefor cell cycle arrest at phase G2Mrdquo Journal of Virology vol 86pp 10748ndash10758 2012

[145] T Takahashi K Ozawa K Takahashi S Asano and F TakakuldquoSusceptibility of human erythropoietic cells to B19 parvovirusin vitro increases with differentiationrdquo Blood vol 75 no 3 pp603ndash610 1990

[146] N Yaegashi T Niinuma H Chisaka et al ldquoParvovirus B19infection induces apoptosis of erythroid cells in vitro and invivordquo Journal of Infection vol 39 no 1 pp 68ndash76 1999

[147] A Nakashima N Tanaka K Tamai et al ldquoSurvival of par-vovirus B19-infected cells by cellular autophagyrdquo Virology vol349 no 2 pp 254ndash263 2006

[148] Y Munakata I Kato T Saito T Kodera K K Ishii and TSasaki ldquoHuman parvovirus B19 infection of monocytic celllineU937 and antibody-dependent enhancementrdquoVirology vol345 no 1 pp 251ndash257 2006

[149] K Zakrzewska R Cortivo C Tonello et al ldquoHumanparvovirusB19 experimental infection in human fibroblasts and endothe-lial cells culturesrdquo Virus Research vol 114 no 1-2 pp 1ndash5 2005

[150] A Duechting C Tschope H Kaiser et al ldquoHuman parvovirusB19 NS1 protein modulates inflammatory signaling by activa-tion of STAT3PIAS3 in human endothelial cellsrdquo Journal ofVirology vol 82 no 16 pp 7942ndash7952 2008

[151] T Pozzuto K von Kietzell T Bock et al ldquoTransactivation ofhuman parvovirus B19 gene expression in endothelial cells byadenoviral helper functionsrdquo Virology vol 411 pp 50ndash64 2011

[152] N P H Miki and J K Chantler ldquoNon-permissiveness ofsynovial membrane cells to human parvovirus B19 in vitrordquoJournal of General Virology vol 73 no 6 pp 1559ndash1562 1992

[153] Y Takahashi CMurai S Shibata et al ldquoHuman parvovirus B19as a causative agent for rheumatoid arthritisrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 95 no 14 pp 8227ndash8232 1998

[154] N B Ray D R Nieva E A Seftor Z Khalkhali-Ellis andS J Naides ldquoInduction of an invasive phenotype by humanparvovirus B19 in normal human synovial fibroblastsrdquo Arthritisamp Rheumatism vol 44 pp 1582ndash1586 2001

[155] J Lu N Zhi S Wong and K E Brown ldquoActivation ofsynoviocytes by the secreted phospholipase A2 motif in theVP1-unique region of parvovirus B19 minor capsid proteinrdquoJournal of Infectious Diseases vol 193 no 4 pp 582ndash590 2006

[156] P Cassinotti G Burtonboy M Fopp and G Siegl ldquoEvidencefor persistence of human parvovirus B19DNA in bonemarrowrdquoJournal of Medical Virology vol 53 pp 229ndash232 1997

[157] P Cassinotti G Siegl B A Michel and P Bruhlmann ldquoPres-ence and significance of humanparvovirus B19DNA in synovialmembranes and bone marrow from patients with arthritis ofunknown originrdquo Journal of Medical Virology vol 56 pp 199ndash204 1998

[158] A Manning S J Willey J E Bell and P Simmonds ldquoCompar-ison of tissue distribution persistence and molecular epidemi-ology of parvovirus B19 and novel human parvoviruses PARV4and human bocavirusrdquo Journal of Infectious Diseases vol 195no 9 pp 1345ndash1352 2007

[159] A M Eis-Hbinger U Reber T Abdul-Nour U Glatzel HLauschke and U Ptz ldquoPersistence of parvovirus B19 DNA insynovium of patients with haemophilic arthritisrdquo Journal ofMedical Virology vol 65 no 2 pp 402ndash407 2001

[160] S Modrow ldquoParvovirus B19 the causative agent of dilated car-diomyopathy or a harmless passenger of the human myocardrdquoErnst Schering Research Foundation workshop no 55 pp 63ndash82 2006

[161] M Soderlund R von Essen J Haapasaari U Kiistala OKiviluoto and K Hedman ldquoPersistence of parvovirus B19 DNAin synovial membranes of young patients with and withoutchronic arthropathyrdquo The Lancet vol 349 no 9058 pp 1063ndash1065 1997

[162] F Bonvicini M La Placa E Manaresi et al ldquoParvovirus B19DNA is commonly harboured in human skinrdquo Dermatologyvol 220 no 2 pp 138ndash142 2010

[163] T Tolfvenstam N Papadogiannakis A Andersen andO AkreldquoNo association between human parvovirus B19 and testiculargerm cell cancerrdquo Journal of General Virology vol 83 no 9 pp2321ndash2324 2002

[164] K Hokynar J Brunstein M Soderlund-Venermo et alldquoIntegrity and full coding sequence of B19 virus DNA persistingin human synovial tissuerdquo Journal of General Virology vol 81no 4 pp 1017ndash1025 2000

[165] M J Anderson P G Higgins L R Davis et al ldquoExperimentalparvoviral infection in humansrdquo The Journal of InfectiousDiseases vol 152 pp 257ndash265 1985

[166] C G Potter A C Potter and C S R Hatton ldquoVariation oferythroid andmyeloid precursors in themarrow and peripheralblood of volunteer subjects infected with human parvovirus(B19)rdquo Journal of Clinical Investigation vol 79 no 5 pp 1486ndash1492 1987

[167] A Srivastava E Bruno R Briddell et al ldquoParvovirus B19-induced perturbation of humanmegakaryocytopoiesis in vitrordquoBlood vol 76 no 10 pp 1997ndash2004 1990

[168] K E Brown ldquoHaematological consequences of parvovirusB19 infectionrdquo Baillierersquos Best Practice and Research in ClinicalHaematology vol 13 no 2 pp 245ndash259 2000

[169] M Musiani M Zerbini G Gentilomi M Plazzi G Gallinellaand S Venturoli ldquoParvovirus B19 clearance from peripheralblood after acute infectionrdquo Journal of Infectious Diseases vol172 no 5 pp 1360ndash1363 1995

[170] A LindblomA IsaONorbeck et al ldquoSlow clearance of humanparvovirus B19 viremia following acute infectionrdquo ClinicalInfectious Diseases vol 41 no 8 pp 1201ndash1203 2005

[171] J J Lefrere A Servant-Delmas D Candotti et al ldquoPersistentB19 infection in immunocompetent individuals implicationsfor transfusion safetyrdquo Blood vol 106 no 8 pp 2890ndash28952005

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Signal TransductionJournal of

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BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

28 ISRN Virology

[172] N S Young J L Abkowitz and L Luzzatto ldquoNew insightsinto the pathophysiology of acquired cytopeniasrdquo HematologyAmerican Society of Hematology Education Program pp 18ndash382000

[173] P R Koduri ldquoParvovirus B19-related anemia in HIV-infectedpatientsrdquo AIDS Patient Care and STDs vol 14 no 1 pp 7ndash112000

[174] K Broliden T Tolfvenstam S Ohlsson and J I HenterldquoPersistent B19 parvovirus infection in pediatric malignanciesrdquoMedical and Pediatric Oncology vol 31 pp 66ndash72 1998

[175] A Lindblom M Heyman I Gustafsson et al ldquoParvovirusB19 infection in children with acute lymphoblastic leukemia isassociated with cytopenia resulting in prolonged interruptionsof chemotherapyrdquo Clinical Infectious Diseases vol 46 no 4 pp528ndash536 2008

[176] G Gallinella EManaresi S Venturoli G L Grazi MMusianiand M Zerbini ldquoOccurrence and clinical role of active par-vovirus B19 infection in transplant recipientsrdquoEuropean Journalof Clinical Microbiology and Infectious Diseases vol 18 no 11pp 811ndash813 1999

[177] K Broliden ldquoParvovirus B19 infection in pediatric solid-organand bone marrow transplantationrdquo Pediatric Transplantationvol 5 no 5 pp 320ndash330 2001

[178] A J Eid R A Brown R Patel andR R Razonable ldquoParvovirusB19 infection after transplantation a review of 98 casesrdquoClinicalInfectious Diseases vol 43 no 1 pp 40ndash48 2006

[179] M J Anderson S E Jones and S P Fisher Hoch ldquoHumanparvovirus the cause of erythema infectiosum (fifth disease)rdquoThe Lancet vol 1 no 8338 p 1378 1983

[180] T Chorba P Coccia and R C Holman ldquoThe role of parvovirusB19 in aplastic crisis and erythema infectiosum (fifth disease)rdquoJournal of Infectious Diseases vol 154 no 3 pp 383ndash393 1986

[181] D G White A D Woolf and P P Mortimer ldquoHumanparvovirus arthropathyrdquo The Lancet vol 1 no 8426 pp 419ndash421 1985

[182] D M Reid T M S Reid and T Brown ldquoHuman parvovirus-associated arthritis a clinical and laboratory descriptionrdquo TheLancet vol 1 no 8426 pp 422ndash425 1985

[183] C Lunardi M Tiso L Borgato et al ldquoChronic parvovirusB19 infection induces the production of anti-virus antibodieswith autoantigen binding propertiesrdquo European Journal ofImmunology vol 28 pp 936ndash948 1998

[184] C Lunardi E Tinazzi C Bason M Dolcino R Corrocher andA Puccetti ldquoHuman parvovirus B19 infection and autoimmu-nityrdquo Autoimmunity Reviews vol 8 no 2 pp 116ndash120 2008

[185] K Klingel M Sauter C T Bock G Szalay J J Schnorr and RKandolf ldquoMolecular pathology of inflammatory cardiomyopa-thyrdquoMedicalMicrobiology and Immunology vol 193 no 2-3 pp101ndash107 2004

[186] L Andreoletti N Leveque C Boulagnon C Brasselet andP Fornes ldquoViral causes of human myocarditisrdquo Archives ofCardiovascular Diseases vol 102 no 6-7 pp 559ndash568 2009

[187] S Pankuweit and K Klingel ldquoViral myocarditis from experi-mentalmodels tomolecular diagnosis in patientsrdquoHeart FailureReviews 2012

[188] K O Schowengerdt J Ni S W Denfield et al ldquoAssociationof parvovirus B19 genome in children with myocarditis andcardiac allograft rejection diagnosis using the polymerase chainreactionrdquo Circulation vol 96 no 10 pp 3549ndash3554 1997

[189] R Dettmeyer R Kandolf A Baasner S Banaschak A M Eis-Hubinger and B Madea ldquoFatal parvovirus B19 myocarditis in

an 8-year-old boyrdquo Journal of Forensic Sciences vol 48 no 1 pp183ndash186 2003

[190] K Munro M C Croxson S Thomas and N J Wilson ldquoThreecases of myocarditis in childhood associated with humanparvovirus (B19 virus)rdquo Pediatric Cardiology vol 24 no 5 pp473ndash475 2003

[191] F Zack K Klingel R Kandolf and R Wegener ldquoSuddencardiac death in a 5-year-old girl associated with parvovirus B19infectionrdquo Forensic Science International vol 155 no 1 pp 13ndash17 2005

[192] J P Breinholt M Moulik W J Dreyer et al ldquoViral epidemio-logic shift in inflammatory heart disease the increasing involve-ment of parvovirus B19 in the myocardium of pediatric cardiactransplant patientsrdquo Journal of Heart and Lung Transplantationvol 29 no 7 pp 739ndash746 2010

[193] B D Bultmann K Klingel K Sotlar et al ldquoFatal parvovirusB19-associatedmyocarditis clinically mimicking ischemic heartdisease an endothelial cell-mediated diseaserdquo Human Pathol-ogy vol 34 no 1 pp 92ndash95 2003

[194] U Kuhl M Pauschinger T Bock et al ldquoParvovirus B19infection mimicking acute myocardial infarctionrdquo Circulationvol 108 no 8 pp 945ndash950 2003

[195] H Mahrholdt A Wagner C C Deluigi et al ldquoPresentationpatterns of myocardial damage and clinical course of viralmyocarditisrdquo Circulation vol 114 no 15 pp 1581ndash1590 2006

[196] C T Bock K Klingel and R Kandolf ldquoHuman parvovirus B19-associated myocarditisrdquo The New England Journal of Medicinevol 362 no 13 pp 1248ndash1249 2010

[197] S Pankuweit R Moll U Baandrup I Portig G Hufnageland B Maisch ldquoPrevalence of the parvovirus B19 genome inendomyocardial biopsy specimensrdquo Human Pathology vol 34no 5 pp 497ndash503 2003

[198] O Donoso Mantke A Nitsche R Meyer K Klingel and MNiedrig ldquoAnalysing myocardial tissue from explanted heartsof heart transplant recipients and multi-organ donors for thepresence of parvovirus B19 DNArdquo Journal of Clinical Virologyvol 31 no 1 pp 32ndash39 2004

[199] O D Mantke R Meyer S Prosch et al ldquoHigh prevalenceof cardiotropic viruses in myocardial tissue from explantedhearts of heart transplant recipients and heart donors a 3-yearretrospective study from a German patientsrsquo poolrdquo Journal ofHeart and Lung Transplantation vol 24 no 10 pp 1632ndash16382005

[200] R M Klein H Jiang D Niederacher et al ldquoFrequency andquantity of the parvovirus B19 genome in endomyocardialbiopsies from patients with suspectedmyocarditis or idiopathicleft ventricular dysfunctionrdquo Zeitschrift fur Kardiologie vol 93no 4 pp 300ndash309 2004

[201] U Kuhl M Pauschinger B Seeberg et al ldquoViral persistencein the myocardium is associated with progressive cardiacdysfunctionrdquo Circulation vol 112 no 13 pp 1965ndash1970 2005

[202] C Tschope C T Bock M Kasner et al ldquoHigh prevalence ofcardiac parvovirus B19 infection in patients with isolated leftventricular diastolic dysfunctionrdquo Circulation vol 111 no 7 pp879ndash886 2005

[203] U Kuhl D Lassner M Pauschinger et al ldquoPrevalence oferythrovirus genotypes in the myocardium of patients withdilated cardiomyopathyrdquo Journal ofMedical Virology vol 80 no7 pp 1243ndash1251 2008

[204] V Ruppert T Meyer A Balbach et al ldquoGenotype-specificeffects on left ventricular function in parvovirus B19-positive

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 29

patients with dilated cardiomyopathyrdquo Journal of Medical Virol-ogy vol 83 no 10 pp 1818ndash1825 2011

[205] R Dennert P van Paassen P Wolffs et al ldquoDifferences in virusprevalence and load in the hearts of patients with idiopathicdilated cardiomyopathy with and without immune-mediatedinflammatory diseasesrdquo Clinical and Vaccine Immunology vol19 pp 1182ndash1187 2012

[206] F Kuethe H H Sigusch K Hilbig et al ldquoDetection of viralgenome in the myocardium lack of prognostic and functionalrelevance in patients with acute dilated cardiomyopathyrdquoAmer-ican Heart Journal vol 153 no 5 pp 850ndash858 2007

[207] F Kuethe J Lindner K Matschke et al ldquoPrevalence of par-vovirus B19 and human bocavirus DNA in the heart of patientswith no evidence of dilated cardiomyopathy or myocarditisrdquoClinical Infectious Diseases vol 49 no 11 pp 1660ndash1666 2009

[208] T Schenk M Enders S Pollak R Hahn and D HuzlyldquoHigh prevalence of human parvovirus B19 DNA inmyocardialautopsy samples from subjects without myocarditis or dilativecardiomyopathyrdquo Journal of Clinical Microbiology vol 47 no 1pp 106ndash110 2009

[209] U Lotze R Egerer B Gluck et al ldquoLow level myocardialparvovirus B19 persistence is a frequent finding in patientswith heart disease but unrelated to ongoing myocardial injuryrdquoJournal of Medical Virology vol 82 no 8 pp 1449ndash1457 2010

[210] G C Stewart J Lopez-Molina R V S R K Gottumukkala etal ldquoMyocardial parvovirus B19 persistence lack of associationwith clinicopathologic phenotype in adults with heart failurerdquoCirculation Heart Failure vol 4 no 1 pp 71ndash78 2011

[211] S A Koepsell D R Anderson and S J Radio ldquoParvovirus B19is a bystander in adult myocarditisrdquo Cardiovascular Pathologyvol 21 pp 476ndash481 2012

[212] SMoimas S ZacchignaMMerlo et al ldquoIdiopathic dilated car-diomyopathy and persistent viral infection lack of associationin a controlled study using a quantitative assayrdquo Heart Lung ampCirculation vol 21 no 12 pp 787ndash793 2012

[213] T L Moore ldquoParvovirus-associated arthritisrdquo Current Opinionin Rheumatology vol 12 pp 289ndash294 2000

[214] J R Kerr ldquoPathogenesis of human parvovirus B19 in rheumaticdiseaserdquo Annals of the Rheumatic Diseases vol 59 no 9 pp672ndash683 2000

[215] Y Mehraein C Lennerz S Ehlhardt et al ldquoDetection ofparvovirus B19 capsid proteins in lymphocytic cells in synovialtissue of autoimmune chronic arthritisrdquoModern Pathology vol16 no 8 pp 811ndash817 2003

[216] L Pironi F Bonvicini P Gionchetti et al ldquoParvovirus B19infection localized in the intestinal mucosa and associatedwith severe inflammatory bowel diseaserdquo Journal of ClinicalMicrobiology vol 47 no 5 pp 1591ndash1595 2009

[217] O Meyer ldquoParvovirus B19 and autoimmune diseasesrdquo JointBone Spine vol 70 no 1 pp 6ndash11 2003

[218] H W Lehmann P von Landenberg and S Modrow ldquoPar-vovirus B19 infection and autoimmune diseaserdquo AutoimmunityReviews vol 2 no 4 pp 218ndash223 2003

[219] P von Landenberg H W Lehmann and S Modrow ldquoHumanparvovirus B19 infection and antiphospholipid antibodiesrdquoAutoimmunity Reviews vol 6 no 5 pp 278ndash285 2007

[220] A Anand E S Gray and T Brown ldquoHuman parvovirusinfection in pregnancy and hydrops fetalisrdquo The New EnglandJournal of Medicine vol 316 no 4 pp 183ndash186 1987

[221] J A Jordan and J A Deloia ldquoGloboside expression within thehuman placentardquo Placenta vol 20 no 1 pp 103ndash108 1999

[222] C C Wegner and J A Jordan ldquoHuman parvovirus B19 VP2empty capsids bind to human villous trophoblast cells in vitrovia the globoside receptorrdquo Infectious Disease in Obstetrics andGynecology vol 12 no 2 pp 69ndash78 2004

[223] J A Jordan D Huff and J A DeLoia ldquoPlacental cellularimmune response in women infected with human parvovirusB19 during pregnancyrdquo Clinical and Diagnostic LaboratoryImmunology vol 8 no 2 pp 288ndash292 2001

[224] J A Jordan and A R Butchko ldquoApoptotic activity in villoustrophoblast cells during B19 infection correlates with clinicaloutcome assessment by the caspase-related M30 cytodeathantibodyrdquo Placenta vol 23 no 7 pp 547ndash553 2002

[225] G Pasquinelli F Bonvicini L Foroni N Salfi andGGallinellaldquoPlacental endothelial cells can be productively infected byparvovirus B19rdquo Journal of Clinical Virology vol 44 no 1 pp33ndash38 2009

[226] J P Clewley B J Cohen and A M Field ldquoDetection ofparvovirus B19DNA antigen and particles in the human fetusrdquoJournal of Medical Virology vol 23 no 4 pp 367ndash376 1987

[227] A L Morey J W Keeling H J Porter and K A FlemingldquoClinical and histopathological features of parvovirus B19infection in the human fetusrdquo British Journal of Obstetrics andGynaecology vol 99 no 7 pp 566ndash574 1992

[228] M Zerbini M Musiani G Gentilomi S Venturoli GGallinella andRMorandi ldquoComparative evaluation of virolog-ical and serological methods in prenatal diagnosis of parvovirusB19 fetal hydropsrdquo Journal of Clinical Microbiology vol 34 no3 pp 603ndash608 1996

[229] F Bonvicini E Manaresi G Gallinella G A Gentilomi MMusiani and M Zerbini ldquoDiagnosis of fetal parvovirus B19infection value of virological assays in fetal specimensrdquo BJOGvol 116 no 6 pp 813ndash817 2009

[230] E P de Jong F J Walther A C M Kroes and D OepkesldquoParvovirus B19 infection in pregnancy new insights andmanagementrdquo Prenatal Diagnosis vol 31 no 5 pp 419ndash4252011

[231] R F Lamont J D Sobel E Vaisbuch et al ldquoParvovirus B19infection in human pregnancyrdquo BJOG vol 118 no 2 pp 175ndash186 2011

[232] H J Porter AMQuantrill andK A Fleming ldquoB19 parvovirusinfection of myocardial cellsrdquo The Lancet vol 1 no 8584 pp535ndash536 1988

[233] A OrsquoMalley C Barry-Kinsella C Hughes et al ldquoParvovirusInfects Cardiac Myocytes in Hydrops Fetalisrdquo Pediatric andDevelopmental Pathology vol 6 no 5 pp 414ndash420 2003

[234] M Enders A Weidner I Zoellner K Searle and G EndersldquoFetal morbidity and mortality after acute human parvovirusB19 infection in pregnancy prospective evaluation of 1018casesrdquo Prenatal Diagnosis vol 24 no 7 pp 513ndash518 2004

[235] L Skjoldebrand-Sparre T Tolfvenstam N Papadogiannakis BWahren K Broliden andMNyman ldquoParvovirus B19 infectionassociationwith third-trimester intrauterine fetal deathrdquoBritishJournal of Obstetrics and Gynaecology vol 107 no 4 pp 476ndash480 2000

[236] T Tolfvenstam N Papadogiannakis O Norbeck K PeterssonandK Broliden ldquoFrequency of human parvovirus B19 infectionin intrauterine fetal deathrdquo The Lancet vol 357 no 9267 pp1494ndash1497 2001

[237] O Norbeck N Papadogiannakis K Petersson T Hirbod KBroliden and T Tolfvenstam ldquoRevised clinical presentationof parvovirus B19-associated intrauterine fetal deathrdquo ClinicalInfectious Diseases vol 35 no 9 pp 1032ndash1038 2002

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

30 ISRN Virology

[238] A Riipinen E Vaisanen M Nuutila et al ldquoParvovirus B19infection in fetal deathsrdquo Clinical Infectious Diseases vol 47 no12 pp 1519ndash1525 2008

[239] F Bonvicini C Puccetti N C Salfi et al ldquoGestational and fetaloutcomes in B19 maternal infection a problem of diagnosisrdquoJournal of Clinical Microbiology vol 49 pp 3514ndash3518 2011

[240] C Puccetti M Contoli F Bonvicini et al ldquoParvovirus B19in pregnancy possible consequences of vertical transmissionrdquoPrenatal Diagnosis vol 32 pp 897ndash902 2012

[241] Z Ergaz and A Ornoy ldquoParvovirus B19 in pregnancyrdquo Repro-ductive Toxicology vol 21 no 4 pp 421ndash435 2006

[242] H T C Nagel T R De Haan F P H A Vandenbussche DOepkes and F JWalther ldquoLong-term outcome after fetal trans-fusion for hydrops associated with parvovirus B19 infectionrdquoObstetrics and Gynecology vol 109 no 1 pp 42ndash47 2007

[243] J M van Klink H M Koopman D Oepkes F J Waltherand E Lopriore ldquoLong-term neurodevelopmental outcomeafter intrauterine transfusion for fetal anemiardquo Early HumanDevelopment vol 87 pp 589ndash593 2011

[244] E P De Jong I T Lindenburg J M van Klink et al ldquoIntrauter-ine transfusion for parvovirus B19 infection long-term neu-rodevelopmental outcomerdquo American Journal of Obstetrics ampGynecology vol 206 pp e1ndashe5 2012

[245] Y M Guo K Ishii M Hirokawa et al ldquoCpG-ODN 2006 andhuman parvovirus B19 genome consensus sequences selectivelyinhibit growth and development of erythroid progenitor cellsrdquoBlood vol 115 no 22 pp 4569ndash4579 2010

[246] G J Hsu B S Tzang C C Tsai C C Chiu C Y Huangand T C Hsu ldquoEffects of human parvovirus B19 on expressionof defensins and Toll-like receptorsrdquo The Chinese Journal ofPhysiology vol 54 pp 367ndash376 2011

[247] H Sato J Hirata M Furukawa et al ldquoIdentification of theregion including the epitope for a monoclonal antibody whichcan neutralize human parvovirus B19rdquo Journal of Virology vol65 no 4 pp 1667ndash1672 1991

[248] H Sato J Hirata N Kuroda H Shiraki Y Maeda and KOkochi ldquoIdentification andmapping of neutralizing epitopes ofhuman parvovirus B19 by using human antibodiesrdquo Journal ofVirology vol 65 no 10 pp 5485ndash5490 1991

[249] K Yoshimoto S Rosenfeld N Frickhofen et al ldquoA secondneutralizing epitope of B19 parvovirus implicates the spikeregion in the immune responserdquo Journal of Virology vol 65 no12 pp 7056ndash7060 1991

[250] S J Rosenfeld K Yoshimoto S Kajigaya et al ldquoUnique regionof theminor capsid protein of human parvovirus B19 is exposedon the virion surfacerdquo Journal of Clinical Investigation vol 89no 6 pp 2023ndash2029 1992

[251] S J Rosenfeld N S Young D Alling J Ayub and C SaxingerldquoSubunit interaction in B19 parvovirus empty capsidsrdquo Archivesof Virology vol 136 no 1-2 pp 9ndash18 1994

[252] T Saikawa S Anderson M Momoeda S Kajigaya and N SYoung ldquoNeutralizing linear epitopes of B19 parvovirus clusterin the VP1 unique and VP1-VP2 junction regionsrdquo Journal ofVirology vol 67 no 6 pp 3004ndash3009 1993

[253] S Anderson M Momoeda M Kawase S Kajigaya and NS Young ldquoPeptides derived from the unique region of B19parvovirus minor capsid protein elicit neutralizing antibodiesin rabbitsrdquo Virology vol 206 no 1 pp 626ndash632 1995

[254] M Soderlund C S Brown B J Cohen and K Hedman ldquoAccu-rate serodiagnosis of B19 parvovirus infections bymeasurementof IgG avidityrdquo Journal of Infectious Diseases vol 171 no 3 pp710ndash713 1995

[255] M Soderlund C S Brown W J M Spaan L Hedman andK Hedman ldquoEpitope type-specific IgG responses to capsidproteins VP1 and VP2 of human parvovirus B19rdquo Journal ofInfectious Diseases vol 172 no 6 pp 1431ndash1436 1995

[256] E Manaresi G Gallinella M Zerbini S Venturoli G Gen-tilomi and M Musiani ldquoIgG immune response to B19 par-vovirus VP1 and VP2 linear epitopes by immunoblot assayrdquoJournal of Medical Virology vol 57 pp 174ndash178 1999

[257] E Manaresi P Pasini G Gallinella et al ldquoChemiluminescenceWestern blot assay for the detection of immunity against par-vovirus B19 VP1 and VP2 linear epitopes using a videocamerabased luminographrdquo Journal of Virological Methods vol 81 no1-2 pp 91ndash99 1999

[258] M Musiani E Manaresi G Gallinella S Venturoli E Zuffiand M Zerbini ldquoImmunoreactivity against linear epitopes ofparvovirus B19 structural proteins Immunodominance of theamino-terminal half of the unique region of VP1rdquo Journal ofMedical Virology vol 60 pp 347ndash352 2000

[259] E Manaresi E Zuffi G Gallinella G Gentilomi M Zerbiniand M Musiani ldquoDifferential IgM response to conformationaland linear epitopes of parvovirus B19 VP1 and VP2 structuralproteinsrdquo Journal of Medical Virology vol 64 no 1 pp 67ndash732001

[260] E Zuffi E Manaresi G Gallinella et al ldquoIdentification of animmunodominant peptide in the parvovirus B19 VP1 uniqueregion able to elicit a long-lasting immune response in humansrdquoViral Immunology vol 14 no 2 pp 151ndash158 2001

[261] A von Poblotzki A Gigler B Lang H Wolf and S ModrowldquoAntibodies to parvovirus B19NS-1 protein in infected individu-alsrdquo Journal of General Virology vol 76 no 3 pp 519ndash527 1995

[262] A vonPoblotzki AHemauer AGigler et al ldquoAntibodies to thenonstructural protein of parvovirus B19 in persistently infectedpatients implications for pathogenesisrdquo Journal of InfectiousDiseases vol 172 no 5 pp 1356ndash1359 1995

[263] S Venturoli G Gallinella E Manaresi G Gentilomi MMusiani andM Zerbini ldquoIgG response to the immunoreactiveregion of parvovirus B19 nonstructural protein by immunoblotassay with recombinant antigenrdquo Journal of Infectious Diseasesvol 178 no 6 pp 1826ndash1829 1998

[264] K Searle G Schalasta and G Enders ldquoDevelopment ofantibodies to the nonstructural protein NS1 of parvovirusB19 during acute symptomatic and subclinical infection inpregnancy implications for pathogenesis doubtfulrdquo Journal ofMedical Virology vol 56 pp 192ndash198 1998

[265] L P Jones D D Erdman and L J Anderson ldquoPrevalence ofantibodies to human parvovirus B19 nonstructural protein inpersons with various clinical outcomes following B19 infectionrdquoJournal of Infectious Diseases vol 180 no 2 pp 500ndash504 1999

[266] A Hemauer A Gigler K Searle et al ldquoSeroprevalence ofparvovirus B19 NS1-specific IgG in B19-infected and uninfectedindividuals and in infected pregnantwomenrdquo Journal ofMedicalVirology vol 60 pp 48ndash55 2000

[267] J R Kerr and V S Cunniffe ldquoAntibodies to parvovirus B19non-structural protein are associatedwith chronic but not acutearthritis following B19 infectionrdquo Rheumatology vol 39 no 8pp 903ndash908 2000

[268] E D Heegaard C J Rasksen and J Christensen ldquoDetection ofparvovirus B19 NS1-specific antibodies by ELISA and westernblotting employing recombinant NS1 protein as antigenrdquo Jour-nal of Medical Virology vol 67 no 3 pp 375ndash383 2002

[269] T Tolfvenstam A Lundqvist M Levi B Wahren and KBroliden ldquoMapping of B-cell epitopes on humanParvovirus B19

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 31

non-structural and structural proteinsrdquo Vaccine vol 19 no 7-8pp 758ndash763 2000

[270] A Corcoran B P Mahon and S Doyle ldquoB cell memory isdirected toward conformational epitopes of parvovirus B19capsid proteins and the unique region of VP1rdquo Journal ofInfectious Diseases vol 189 no 10 pp 1873ndash1880 2004

[271] A vonPoblotzki CGerdesU ReischlHWolf and SModrowldquoLymphoproliferative responses after infection with humanparvovirus B19rdquo Journal of Virology vol 70 no 10 pp 7327ndash7330 1996

[272] R Franssila K Hokynar and K Hedman ldquoT helper cell-mediated in vitro responses of recently and remotely infectedsubjects to a candidate recombinant vaccine for human par-vovirus B19rdquo Journal of Infectious Diseases vol 183 no 5 pp805ndash809 2001

[273] T Tolfvenstam A Oxenius D A Price et al ldquoDirect exvivo measurement of CD8+ T-lymphocyte responses to humanparvovirus B19rdquo Journal of Virology vol 75 no 1 pp 540ndash5432001

[274] O Norbeck A Isa C Pohlmann et al ldquoSustained CD8+ T-cell responses induced after acute parvovirus B19 infection inhumansrdquo Journal of Virology vol 79 no 18 pp 12117ndash121212005

[275] A Isa O Norbeck T Hirbod et al ldquoAberrant cellular immuneresponses in humans infected persistently with parvovirus B19rdquoJournal of Medical Virology vol 78 no 1 pp 129ndash133 2006

[276] A Isa V Kasprowicz O Norbeck et al ldquoProlonged activationof virus-specific CD8+ T cells after acute B19 infectionrdquo PLoSMedicine vol 2 no 12 article e343 pp 1280ndash1291 2005

[277] V Kasprowicz A Isa K Jeffery et al ldquoA highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirusB19 infection in HLA-Alowast2402-positive individualsrdquo Journal ofVirology vol 80 no 13 pp 6697ndash6701 2006

[278] R Franssila and K Hedman ldquoT-helper cell-mediatedinterferon-120574 interleukin-10 and proliferation responses toa candidate recombinant vaccine for human parvovirus B19rdquoVaccine vol 22 no 27-28 pp 3809ndash3815 2004

[279] R Franssila J Auramo S Modrow et al ldquoT helper cell-mediated interferon-gamma expression after human par-vovirus B19 infection persisting VP2-specific and transientVP1u-specific activityrdquo Clinical and Experimental Immunologyvol 142 no 1 pp 53ndash61 2005

[280] V Kasprowicz A Isa T Tolfvenstam K Jeffery P Bownessand P Klenerman ldquoTracking of peptide-specific CD4+ T-cellresponses after an acute resolving viral infection a study ofparvovirus B19rdquo Journal of Virology vol 80 no 22 pp 11209ndash11217 2006

[281] A Isa A Lundqvist A Lindblom T Tolfvenstam and KBroliden ldquoCytokine responses in acute and persistent humanparvovirus B19 infectionrdquo Clinical and Experimental Immunol-ogy vol 147 no 3 pp 419ndash425 2007

[282] J Mossong N Hens V Friederichs et al ldquoParvovirus B19infection in five European countries seroepidemiology forceof infection and maternal risk of infectionrdquo Epidemiology andInfection vol 136 no 8 pp 1059ndash1068 2008

[283] N Goeyvaerts N Hens M Aerts and P Beutels ldquoModelstructure analysis to estimate basic immunological processesand maternal risk for parvovirus B19rdquo Biostatistics vol 12 no2 pp 283ndash302 2011

[284] A Parsyan S Kerr S Owusu-Ofori G Elliott and J PAllain ldquoReactivity of genotype-specific recombinant proteins

of human erythrovirus B19 with plasmas from areas wheregenotype 1 or 3 is endemicrdquo Journal of ClinicalMicrobiology vol44 no 4 pp 1367ndash1375 2006

[285] K E Brown N S Young BM Alving and L H Barbosa ldquoPar-vovirus B19 implications for transfusionmedicine Summary ofa workshoprdquo Transfusion vol 41 no 1 pp 130ndash135 2001

[286] J Blumel R Burger C Drosten et al ldquoParvovirus B19mdashrevisedrdquo Transfusion Medicine and Hemotherapy vol 37 pp339ndash350 2010

[287] M H G M Koppelman H T M Cuypers T Emrich and HL Zaaijer ldquoQuantitative real-time detection of parvovirus B19DNA in plasmardquo Transfusion vol 44 no 1 pp 97ndash103 2004

[288] G Schreiber S H Kleinman S A Glynn et al ldquoPrevalenceand quantitation of parvovirus B19 DNA levels in blood donorswith a sensitive polymerase chain reaction screening assayrdquoTransfusion vol 47 no 10 pp 1756ndash1764 2007

[289] H Matsukura S Shibata Y Tani H Shibata and R A FurutaldquoPersistent infection by human parvovirus B19 in qualifiedblood donorsrdquo Transfusion vol 48 no 5 pp 1036ndash1037 2008

[290] M H G M Koppelman P Van Swieten and H T M CuijpersldquoReal-time polymerase chain reaction detection of parvovirusB19 DNA in blood donations using a commercial and an in-house assayrdquo Transfusion vol 51 no 6 pp 1346ndash1354 2011

[291] K KooistraH JMesmanM deWaalMHGMKoppelmanand H L Zaaijer ldquoEpidemiology of high-level parvovirusB19 viraemia among Dutch blood donors 2003ndash2009rdquo VoxSanguinis vol 100 no 3 pp 261ndash266 2011

[292] S A Baylis and K H Buchheit ldquoA proficiency testing study toevaluate laboratory performance for the detection of differentgenotypes of parvovirus B19rdquo Vox Sanguinis vol 97 no 1 pp13ndash20 2009

[293] S A Baylis L Ma D J Padley A B Heath and M W YuldquoCollaborative study to establish a World Health OrganizationInternational genotype panel for parvovirus B19 DNA nucleicacid amplification technology (NAT)-based assaysrdquoVox Sangui-nis vol 102 no 3 pp 204ndash211 2012

[294] L M Bell S J Naides P Stoffman R L Hodinka and S APlotkin ldquoHuman parvovirus B19 infection among hospital staffmembers after contact with infected patientsrdquoTheNew EnglandJournal of Medicine vol 321 no 8 pp 485ndash491 1989

[295] S M Ray D D Erdman J D Berschling J E CooperT J Torok and H M Blumberg ldquoNosocomial exposure toparvovirus B19 low risk of transmission to healthcare workersrdquoInfection Control and Hospital Epidemiology vol 18 no 2 pp109ndash114 1997

[296] ldquoProspective study of human parvovirus (B19) infection inpregnancy Public Health Laboratory ServiceWorking Party onFifth Diseaserdquo BMJ vol 300 no 6733 pp 1166ndash1170 1990

[297] J HHarger S P Adler andWC Koch ldquoProspective evaluationof 618 pregnant women exposed to parvovirus B19 risks andsymptomsrdquo Obstetrics and Gynecology vol 91 no 3 pp 413ndash420 1998

[298] E Miller C K Fairley B J Cohen and C Seng ldquoImmediateand long term outcome of human parvovirus B19 infection inpregnancyrdquo British Journal of Obstetrics and Gynaecology vol105 no 2 pp 174ndash178 1998

[299] H Chisaka K Ito H Niikura et al ldquoClinical manifestationsand outcomes of parvovirus B19 infection during pregnancy inJapanrdquo Tohoku Journal of Experimental Medicine vol 209 pp277ndash283 2006

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

32 ISRN Virology

[300] A J Vyse N J Andrews L M Hesketh and R Pebody ldquoTheburden of parvovirus B19 infection in women of childbearingage in England andWalesrdquo Epidemiology and Infection vol 135no 8 pp 1354ndash1362 2007

[301] A P Watt M Brown M Pathiraja A Anbazhagan and PV Coyle ldquoThe lack of routine surveillance of Parvovirus B19infection in pregnancy prevents an accurate understandingof this regular cause of fetal loss and the risks posed byoccupational exposurerdquo Journal ofMedicalMicrobiology vol 62pp 86ndash92 2012

[302] I P Jensen P Thorsen B Jeune B R Moslashller and B F Vester-gaard ldquoAn epidemic of parvovirus B19 in a population of 3596pregnantwomen a study of sociodemographic andmedical riskfactorsrdquo British Journal of Obstetrics and Gynaecology vol 107no 5 pp 637ndash643 2000

[303] P H van Gessel M A Gaytant A C Vossen et al ldquoIncidenceof parvovirus B19 infection among an unselected populationof pregnant women in the Netherlands a prospective studyrdquoEuropean Journal of Obstetrics amp Gynecology and ReproductiveBiology vol 128 pp 46ndash49 2006

[304] A A Sarfraz S O Samuelsen A L Bruu P A Jenum and AEskild ldquoMaternal human parvovirus B19 infection and the riskof fetal death and low birthweight a case-control study within35 940 pregnant womenrdquo BJOG vol 116 no 11 pp 1492ndash14972009

[305] J Lassen A K Jensen P Bager et al ldquoParvovirus B19 infectionin the first trimester of pregnancy and risk of fetal lossa population-based case-control studyrdquo American Journal ofEpidemiology vol 176 no 9 pp 803ndash807 2012

[306] N S Young and K E Brown ldquoMechanisms of disease par-vovirus B19rdquoTheNew England Journal of Medicine vol 350 no6 pp 586ndash597 2004

[307] G Gallinella E Zuffi G Gentilomi et al ldquoRelevance of B19markers in serum samples for a diagnosis of parvovirus B19-correlated diseasesrdquo Journal of Medical Virology vol 71 no 1pp 135ndash139 2003

[308] M J Anderson S E Jones and A C Minson ldquoDiagnosis ofhuman parvovirus infection by dot-blot hybridization usingcloned viral DNArdquo Journal of Medical Virology vol 15 no 2pp 163ndash172 1985

[309] J Mori A M Field J P Clewley and B J Cohen ldquoDot blothybridization assay of B19 virus DNA in clincial specimensrdquoJournal of ClinicalMicrobiology vol 27 no 3 pp 459ndash464 1989

[310] M Zerbini M Musiani S Venturoli et al ldquoRapid screening forB19 parvovirus DNA in clinical specimens with a digoxigenin-labeled DNA hybridization proberdquo Journal of Clinical Microbi-ology vol 28 no 11 pp 2496ndash2499 1990

[311] MMusianiM ZerbiniDGibellini et al ldquoChemiluminescencedot blot hybridization assay for detection of B19 parvovirusDNA in human serardquo Journal of Clinical Microbiology vol 29no 9 pp 2047ndash2050 1991

[312] M M M Salimans S Holsappel F M Van De Rijke N MJiwa A K Raap and H TWeiland ldquoRapid detection of humanparvovirus B19 DNA by dot-hybridization and the polymerasechain reactionrdquo Journal of Virological Methods vol 23 no 1 pp19ndash28 1989

[313] W C Koch and S P Adler ldquoDetection of human parvovirusB19 DNA by using the polymerase chain reactionrdquo Journal ofClinical Microbiology vol 28 no 1 pp 65ndash69 1990

[314] E L Durigon D D Erdman G W Gary M A PallanschT J Torok and L J Anderson ldquoMultiple primer pairs for

polymerase chain reaction (PCR) amplification of human par-vovirus B19 DNArdquo Journal of Virological Methods vol 44 no2-3 pp 155ndash165 1993

[315] M Zerbini D Gibellini MMusiani S Venturoli G Gallinellaand G Gentilomi ldquoAutomated detection of digoxigenin-labelled B19 parvovirus amplicons by a capture hybridizationassayrdquo Journal of Virological Methods vol 55 no 1 pp 1ndash9 1995

[316] G Gallinella M Zerbini M Musiani S Venturoli G Gen-tilomi and E Manaresi ldquoQuantitation of parvovirus B19 DNAsequences by competitive PCR differential hybridization ofthe amplicons and immunoenzymatic detection onmicroplaterdquoMolecular and Cellular Probes vol 11 no 2 pp 127ndash133 1997

[317] M Musiani G Gallinella S Venturoli and M Zerbini ldquoCom-petitive PCR-ELISA protocols for the quantitative and thestandardized detection of viral genomesrdquo Nature protocols vol2 no 10 pp 2511ndash2519 2007

[318] C Aberham C Pendl P Gross G Zerlauth and M GessnerldquoA quantitative internally controlled real-time PCR assay forthe detection of parvovirus B19 DNArdquo Journal of VirologicalMethods vol 92 no 2 pp 183ndash191 2001

[319] F Gruber F G Falkner F Dorner and T Hammerle ldquoQuanti-tation of viral DNA by real-time PCR applying duplex ampli-fication internal standardization and two-color fluorescencedetectionrdquoApplied and Environmental Microbiology vol 67 no6 pp 2837ndash2839 2001

[320] E Manaresi G Gallinella E Zuffi F Bonvicini M Zerbiniand M Musiani ldquoDiagnosis and quantitative evaluation ofparvovirus B19 infections by real-time PCR in the clinicallaboratoryrdquo Journal of Medical Virology vol 67 no 2 pp 275ndash281 2002

[321] G Gallinella F Bonvicini C Filippone et al ldquoCalibrated real-time PCR for evaluation of parvovirus B19 viral loadrdquo ClinicalChemistry vol 50 no 4 pp 759ndash762 2004

[322] MMM Salimans FM Van de Rijke A K Raap andAMWVan Elsacker-Niele ldquoDetection of parvovirus B19 DNA in fetaltissues by in situ hybridisation and polymerase chain reactionrdquoJournal of Clinical Pathology vol 42 no 5 pp 525ndash530 1989

[323] A L Morey H J Porter J W Keeling and K A FlemingldquoNon-isotopic in situ hybridisation and immunophenotypingof infected cells in the investigation of human fetal parvovirusinfectionrdquo Journal of Clinical Pathology vol 45 no 8 pp 673ndash678 1992

[324] G GentilomiM ZerbiniMMusiani et al ldquoIn situ detection ofB19 DNA in bone marrow of immunodeficient patients using adigoxigenin-labelled proberdquoMolecular and Cellular Probes vol7 no 1 pp 19ndash24 1993

[325] G Gallinella N S Young and K E Brown ldquoIn situ hybridi-sation and in situ polymerase chain reaction detection of par-vovirus B19 DNA within cellsrdquo Journal of Virological Methodsvol 50 no 1ndash3 pp 67ndash74 1994

[326] F Bonvicini C Filippone E Manaresi et al ldquoPeptide nucleicacid-based in situ hybridization assay for detection of par-vovirus B19 nucleic acidsrdquo Clinical Chemistry vol 52 no 6 pp973ndash978 2006

[327] F Bonvicini MMirasoli G Gallinella M ZerbiniMMusianiand A Roda ldquoPNA-based probe for quantitative chemilumi-nescent in situ hybridisation imaging of cellular parvovirus B19replication kineticsrdquo Analyst vol 132 no 6 pp 519ndash523 2007

[328] A L Morey H J OrsquoNeill P V Coyle and K A FlemingldquoImmunohistological detection of human parvovirus B19 informalin-fixed paraffin-embedded tissuesrdquo Journal of Pathol-ogy vol 166 no 2 pp 105ndash108 1992

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

ISRN Virology 33

[329] A L Morey D J P Ferguson and K A Fleming ldquoCombinedimmunocytochemistry and non-isotopic in situ hybridizationfor the ultrastructural investigation of human parvovirus B19infectionrdquo Histochemical Journal vol 27 no 1 pp 46ndash53 1995

[330] B J Cohen P PMortimer andM S Pereira ldquoDiagnostic assayswith monoclonal antibodies for the human serum parvovirus-like virus (SPLV)rdquo Journal of Hygiene vol 91 no 1 pp 113ndash1301983

[331] L J Anderson C Tsou and R A Parker ldquoDetection ofantibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assayrdquo Journal of Clinical Microbiologyvol 24 no 4 pp 522ndash526 1986

[332] S Kerr G OrsquoKeeffe C Kilty and S Doyle ldquoUndenaturedparvovirus B19 antigens are essential for the accurate detectionof parvovirus B19 IgGrdquo Journal of Medical Virology vol 57 pp179ndash185 1999

[333] E Manaresi G Gallinella S Venturoli M Zerbini and MMusiani ldquoDetection of parvovirus B19 IgG choice of antigensand serological testsrdquo Journal of Clinical Virology vol 29 no 1pp 51ndash53 2004

[334] L Kaikkonen H Lankinen I Harjunpaa et al ldquoAcute-phase-specific heptapeptide epitope for diagnosis of parvovirus B19infectionrdquo Journal of Clinical Microbiology vol 37 no 12 pp3952ndash3956 1999

[335] M Enders G Schalasta C Baisch et al ldquoHuman parvovirusB19 infection during pregnancymdashvalue of modern molecularand serological diagnosticsrdquo Journal of Clinical Virology vol 35no 4 pp 400ndash406 2006

[336] M Y W Yu H J Alter M L A Virata-Theimer et alldquoParvovirus B19 infection transmitted by transfusion of redblood cells confirmed by molecular analysis of linked donorand recipient samplesrdquo Transfusion vol 50 no 8 pp 1712ndash17212010

[337] M K Hourfar U Mayr-Wohlfart A Themann et al ldquoRecipi-ents potentially infected with parvovirus B19 by red blood cellproductsrdquo Transfusion vol 51 no 1 pp 129ndash136 2011

[338] S H Kleinman S A Glynn T H Lee et al ldquoA linked donor-recipient study to evaluate parvovirus B19 transmission byblood component transfusionrdquo Blood vol 114 no 17 pp 3677ndash3683 2009

[339] A Parsyan and D Candotti ldquoHuman erythrovirus B19 andblood transfusionmdashan updaterdquo Transfusion Medicine vol 17no 4 pp 263ndash278 2007

[340] J Brennand and A Cameron ldquoFetal anaemia diagnosis andmanagementrdquo Best Practice and Research in Clinical Obstetricsand Gynaecology vol 22 no 1 pp 15ndash29 2008

[341] L Mouthon and O Lortholary ldquoIntravenous immunoglobulinsin infectious diseases where do we standrdquo Clinical Microbiol-ogy and Infection vol 9 no 5 pp 333ndash338 2003

[342] Y Crabol B Terrier F Rozenberg et al ldquoIntravenousimmunoglobulin therapy for pure red cell aplasia related tohuman parvovirus B19 infection a retrospective study of 10patients and reviewof the literaturerdquoClinical InfectiousDiseasesvol 56 no 7 pp 968ndash977 2012

[343] P Morelli G Bestetti E Longhi C Parravicini M Corbellinoand L Meroni ldquoPersistent parvovirus B19-induced anemia inan HIV-infected patient under HAART Case report and reviewof literaturerdquo European Journal of Clinical Microbiology andInfectious Diseases vol 26 no 11 pp 833ndash837 2007

[344] J P Rerolle E Morelon I Helal M N Peraldi M F Mamzer-Bruneel and H Kreis ldquoParvovirus B19-related anaemia after

renal transplantationrdquo Scandinavian Journal of Infectious Dis-eases vol 36 no 6-7 pp 513ndash516 2004

[345] A Gigler S Dorsch A Hemauer et al ldquoGeneration of neu-tralizing human monoclonal antibodies against parvovirus B19proteinsrdquo Journal of Virology vol 73 no 3 pp 1974ndash1979 1999

[346] G P Bansal J A Hatfield F E Dunn et al ldquoCandidaterecombinant vaccine for human B19 parvovirusrdquo Journal ofInfectious Diseases vol 167 no 5 pp 1034ndash1044 1993

[347] W R Ballou J L Reed W Noble N S Young and S KoenigldquoSafety and immunogenicity of a recombinant parvovirus B19vaccine formulated with MF59C1rdquo Journal of Infectious Dis-eases vol 187 no 4 pp 675ndash678 2003

[348] D I Bernstein H M El Sahly W A Keitel et al ldquoSafetyand immunogenicity of a candidate parvovirus B19 vaccinerdquoVaccine vol 29 pp 7357ndash7363 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Molecular Biology International

GenomicsInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioinformaticsAdvances in

Marine BiologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Signal TransductionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Evolutionary BiologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Genetics Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Enzyme Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Microbiology