ETIOLOGY VS PATHOGENESIS

Etiology- genetic predisposition- environmental factors: triggering/protective

Pathogenesis- nature of autoantigen(s)- effector mechanisms- regulatory circuits

Monozygotic twins

INTRAFAMILY CONCORDANCE RATES FOR MAJOR AUTOIMMUNE DISEASES

Type I diabetesGraves diseaseCrohn’s diseaseMultiple sclerosisSystemic lupus

erythematosusRheumatoid arthritisMyasthenia gravis

35-50 %

30-60 %

40 %

10-20 %

25-50 %

10-30 %

40 %

7 %

7 %

4 %

0-4 %

2-10 %

5-10 %

1-2 %

15 %

15 %

15 %

Monozygotic twins

Siblings

HLA identical siblings

HLA ASSOCIATIONS WITH AUTOIMMUNE DISEASES

Strong associationankylosing spondylitisceliac diseasetype 1 diabetesGoodpasture’s syndromepemphigus vulgarisacute anterior uveitis

Mild associationpsoriasismultiple sclerosisrheumatoid arthritisGrave’s diseaseHashimoto’s thyroiditisSystemic lupus erythematosusMyasthenia gravis

B27DQ2

DR3/4DR2DR4B27

CW6DR2DR4DR3DR5DR3

B8/DR3

905025161410

7.564

3.5333

AlleleRelative risk(Odd’s ratio)

Disease

The autoantigen gene (CHRNA) :The -subunit of AChR

Exon I Exon IIIntron I

Microsatellites

HB BB

ETIOLOGY OF AUTOIMMUNE DISEASES

Genetic Predisposition

Environement

Chance

Epigenetics

Thyroiditis score

weeks

NOD.H2k

CBA/J

5228108640

1

2

3

4

3

Comparative evolution of experimental allergic thyroiditis in CBA/J and congenic NOD.H2k mice

ANTIGEN MIMICRY AND GUILLAIN-BARRE SYNDROME

_______

Galβ1-3GalNAcβ1-4(NeuAcα2-3)Galβ1-

Lipooligosaccharide derived from

Campylobacter jejuni

Human GM1 ganglioside

In human peripheral nerves

(N. Yuki et al, PNAS 2004, 101, 31)

Induction of Guillain-Barré syndrome by immunization against a Campylobacter jejuni lipooligosaccharide

Yuki et al, PNAS 2004

MULTIPLICITY OF AUTOANTIBODIES IN INSULIN-DEPENDENT DIABETES

MELLITUS

Insulin

Glutamic acid decarboxylase (GAD)

IA-2 (tyrosine phosphatase)

p69

Gangliosides

Carboxypeptidase H

MULTIPLICITY OF AUTOANTIBODIES IN MYASTHENIA GRAVIS

Acetylcholine receptor

chain

chain

chain

Striated muscle

actin

actinin

myosin

titin

ryanodine receptor

rapsyn

3

20 40 60 80Days post-infection

2

1

00

Me

an c

linic

al s

core

Development of myelin specific T cells in SJL mice chronically infected by Theiler's virus

S.D. Miller et al, 1997

DT

H

E

ar s

we

lling

(

x 10

-4in

.) ±

SE

MDays post TMEV infection

34 42 52 58 81

20

30

10

0

TMEV VP270-86 PLP 139-151 PLP 178-191

T cell-mediatedinflammation

Ag1Ag2Ag3…

TH1

Ag1 + APC

TH1 / Ag1

APC + Ag1

TH1 / Ag1

APC + Ag2

TH1 / Ag2

Non immunologic inflammation

Triggering

Amplification+ chronicity

CANDIDATE VIRUSES IN AUTOIMMUNE DISEASES

Multiple sclerosisMeaslesHTLV-1 and other retroviruses (MSRV, HRES-1)HHV 6Other viruses: EBV, JCV, varicella, HSV1/2, rubella

Insulin dependent diabetes mellitusRubellaEnteroviruses (Cocksackie A and B, Echovirus 6 and 9)Endogenous retroviruses Other viruses: mumps, CMV, rotavirus

0 5 10 15 20 25 30 35 40 45 50 55 60

Age

Mul

tiple

Scl

eros

is In

cide

nce

Rat

e

Late EBV Infection With IM

Early EBV Infection Without IM

No EBV Infection

Thacker et al. Annals Neurol 2006

High hygiene,No EBV

High hygiene,+ EBV

219

159

175

175 17

8140

198135

119

6075

75

130

60

100

102

57

57

116

95

67

69

126

106

116

75129

112

124

89

110

69

60

6143

70

574252

48

225

100

141

136

93

88

107

115

145

66

Kurtzke et al. Neurology 1985, 35, 672-678.

Case/control ratios of MS *100 by state of EAD – based on > 5,300 MS cases in US Army Veterans

119112

Relative risk of MS for white males of World War II or the Korean conflict by tier of residence at birth and at entry into active duty (EAD), coterminous US only.

Adapted from Kurtzke et al. Neurology 1985

P for no change in birthplace risk: All=0.0003; North=0.003; Middle=0.002; South=0.57

North

0,711.0 (ref)

1,31

N M S

1,131.20 1.0 (ref)

North Middle South

0,520.82

1.0 (ref)

N M S

Middle

South

EAD Tier

Tier of birth

5.3

1.9 (56-74)

3.78

1.69 24

0.96 (mortality or incidence)

2.2

5

1.1

2.24

3.94

3.3

1.72

Incidence of multiple sclerosis(per 100,000)

24 (77-85)

9.4

7.3 (66-89)

8.05 (54-86)

11.5 (67-90)

19.9

10.9 (85-88)

7.7

19.7

35.8 (87-99)

13.7

Incidence of IDDM(per 100,000)

IDDM incidence in children of migrants from Pakistan to Yorkshire

Staines A. (1997) and Bodansky H.J. (1992)

0

2

4

6

8

10

12

Pakistan Migrant's children

Yorkshire

Incidence of diabetes / 105

IBD & Industrialization and urbanization

IDDM

Multiple sclerosis

Crohn's disease

Asthma

55

Incidence of prototype infectious disease and immune disorders over 4 decades

75 85 95

100

50

Infectious disease

%

100

200

Immune disorders

%300

0

65

Hepatitis A

Rheumatic fever

Measles

Tuberculosis

55 75 85 9565

FACTORS CONTRIBUTING TO THE APPEARANCE OF INFECTIONS

Sources of pathogenic agents

- drinking water

- food (cold storage)

- climate

- housing conditions

- hygiene (worms….)

Anti-infectious defense

- nutrition

- antibiotics

- vaccination

CAUSAL LINK

• ANIMAL MODELS

• CLINICAL TRIALS (PROOF OF CONCEPT)

Effect of infections on diabetes incidence in female NOD mice

0

Age (weeks)

20 40 60 800

25

0

50

75

100

20 40 60 80

% d

iab

etic

Decontamination (isolation)

G1 (n = 177) G2 (n = 200)

G1 (n = 236) G2 (n = 210)

PREVENTION OF IDDM IN NOD MICE BY INFECTIOUS AGENTS

Bacteria streptococcisalmonellamycobacteria (CFA, BCG, …)

Viruses LCMVMHVLDHV

Parasites schistosomaoxyures

Age (days)

0

20

40

60

80

100%

100 200 300 100 200 300

Controls

Mice infected

Effect of malaria in B / W mice

Proteinurie Mortality

B. M. Greenwood et al, 1970

MECHANISMS

1. Antigenic competition

Effect on antigen presentation

- preemption (phagocytosis)

- antigen processing

- antigen binding to MHC molecules

Competition for homeostatic signals

2. Antigen-induced immunoregulation(by-stander suppression)

Th1/Th2 cells

Th3 cells

NKT cells

CD25+ T cells

Th2 cytokines are not

involved

0

20

40

60

80

3 7 11 15 18 23 31 35 38 4327

anti-IL-10R

NOD témoins

NOD OM-85+ anti-IL-10R

NOD OM-85

0

20

40

60

80

100

3 7 11 15 19 23 27 31

OM-85

NOD OM-85

NOD IL-4-/- controls

NOD IL-4-/- OM-85

Age (weeks)

Age (weeks)

OM-85

% d

iab

etes

% d

iab

etes

,,,,,,,,,,,,,,,,,,

,,,,,

,

,,

,,

,,

,,,,,,, ,

,,,, ,,, ,,,, ,,,, ,

, , , ,

, , ,

,

,,,

, , ,

TGF- antibody treatment abrogates diabetes protection by OM-85

0

20

40

60

3 7 11 15 19 23 27Age (weeks)

OM-85 anti-TGF-

NOD OM-85

NOD controls

NOD OM-85+ anti-TGF-

% d

iab

etes

,,,, ,, ,,

,,, ,,,

,,,, ,,

Rôle of natural regulatory CD4+CD25+ T cells

3 7 11 1519 23 27 31

Age (weeks)

20

40

60

0

% d

iab

etes

NOD CD28-/- OM-85

NOD CD28-/- controls

OM-85

3. Non-antigen-mediated effects

Toll-like receptors (regulatory cytokines)

Superantigens (depletion of T cell subsets)

Immunosuppressive proteins

Immune response of dendritic cell to TLR agonists

Th1IL-2,

TNF-, IFN-

vvv v

vv

vvvv

TLR4

TLR5

TLR2

FlagellinEndotoxins or LPSMycobacterial soluble factorProteine MMLVMannanFibrinogenHSP70, HSP60HyaluronanBeta-defensinSurfactant Protein A

LipoproteinsZymosanP. Gingivalis LPSLipoteichoic acidLipoarabinomannanHCMVTrypanosoma cruzi GPIKOmpAHSP70

vv

vv TLR7

vv TLR9

TLR3

TLR1

TLR11

vv TLR8

vvTLR6

Bacterial DNA (CpG)Herpes simplex virus 2

upec

ImidazoquinolinedsARN

ssARNPoly(I:C)

Lipopeptide

lipopeptide

IRF3NF-BAP-1

ImidazoquinolineMyD-88 TRIF

Th2IL-4, IL-5,

IL-10, IL-13

IFN

Regulatory T cells

Allergy & Autoimmunity

TLR2, TLR3,TLR4 and TLR7 agonists delay T1D onset

Type 1 diabetes

Dia

bete

s in

cide

nce

(%)

Age (weeks)

TLR2 TLR3 TLR4 TLR7

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25

Non treatedP40

p=0.0064

Treatment

0102030405060708090

100

5 15 25

Non treatedPoly(I:C)

p=0.000450

10

20

30

40

50

60

70

80

5 10 15 20 25

Non treatedLPS

p=0.00850

102030405060708090

5 10 15 20 25

Non treatedR848

p=0.0143

Similar protective results were obtained with TLR agonists : synthetic lipopetide Pam3CSK4 (TLR2 agonist) or dsRNA Poly(I)Poly(C) …

TLR2 agonist stimulates splenocytes to produce IL-10 and TGF-via MyD88

IL-10 TGF-

0

20

40

60

80

100

120

140

160

180

- 2 20

MyD88+/+

MyD88-/-

P40 (g/ml)

0

100

200

300

400

500

600

700

800

900

1000

- 2 20

MyD88+/+

MyD88-/-

P40 (g/ml)

p=0,0042

p=0,2848

NOD CD1d+/+ NOD CD1d-/-

Protection mediated by a TLR3 agonist is dependent on iNKT cells

TLR3-induced protection is IL-4-dependent

0

10

20

30

40

50

60

70

80

90

100

5 10 15 20 25

NOD WT Non treatedNOD WT Poly(I)Poly(C)NOD IL4 KO Non treatedNOD IL4 KO Poly(I)Poly(C)

Incid

en

ce o

f d

iab

ete

s (

%)

Age (weeks)

NOD.MyD88−/− mice are resistant to the development of type 1 diabetes

0

20

40

60

80

100

0 5 10 15 20 25 30

Weeks of age

Inci

denc

e of

dia

bete

s (%

)

MyD88w t

MyD88Ko

Type 1 diabetes

Allergic asthma model

Immunization100 µg OVA + Alum i.p.

D0 D10Measurement of airwayhyperreactivity to metacholine

Sacrifice and collection ofSera (cytokines, IgE)BALFs (cells, cytokines)Lungs (cytokines)

D6, D7, D8 : treatment with TLR agonist

D7, D8, D9

OVA challenge

NOD.MyD88−/− mice are hyperreactive to allergic asthma

Allergic

asthma

NOD.MyD88−/− mice died during the protocol of experimental allergic asthma

at the time of the second challenge.

When mice were decontaminated, death occured between the first and the second challenge. (5 independent experiments, 40 mice)

Prevention of allergic asthma by a TLR2 agonist

Allergic

asthma

-2 -1 0 1 2 3 4 5 6 7 8 9

1.53.04.56.07.59.0

OVA/P40

Saline/Vehicle Saline/P40

OVA/Vehicle

Pen

h

OVA Saline OVA Saline0

1500

3000

4500

6000

P40-treated Vehicle-injected

p=0,0357

Lung

eot

axin

leve

l (pg

/ml)

OVA Saline OVA Saline0

50

100

150

200 p=0,0736

Lung

IL-4

leve

l (pg

/ml)

P40-treated VehicleP40-treated Vehicle

Similar results using the TLR4 agonist LPS

CNRS UMR 8147 Paris

N. ThieblemontA. Aumeunier

E. BardelM. Dy

F. GrelaA. Ramadan

INSERM U580 Paris

J. F. BachM. A. Alyanakian

L. ChatenoudC. Gouarin

INSERM U564 Angers

P. Jeannin

Department of Host disease Osaka

S. Akira

Acknowledgements