laboratorio e diagnosis di celiachia: update 2014congresso2015.sibioc.it/dia/8409.pdf · celiachia:...

Alessio Fasano, M.D.

Mucosal Immunology and Biology Research Center

And Center for Celiac Research

Massachusetts General Hospital, Boston MA – U.S.A.

Laboratorio e Diagnosis di

Celiachia: Update 2014 46o Congresso Nazionale SIBioC

Roma 13-15 Ottobre 2014

Objectives

• Definition of celiac disease;

• Pathogenesis of celiac disease;

• Overview of clinical presentations of celiac

disease;

• Current and immediate future diagnostic tools;

• Clinical performance and technical challanges of

current diagnostic tools;

• Epidemiology (getting in celiac disease

diagnostics is a good business decision!);

• Future diagnostic directions.

The Banana Babies

WK Dicke, 1905 - 1962 1st case of CD at UMB: 1938

Celiac Disease as a Unique

Model of Autoimmunity

• The only autoimmune disease in which specific MHC class II HLA (DQ2 and/or DQ8) are present in >95% of patients;

• The auto-antigen (tissue Transglutaminase) is known;

• The environmental trigger (gluten) is known;

• Elimination of the environmental trigger leads to a complete resolution of the autoimmune process that can be re-ignited following re-exposure to gluten

The Celiac Iceberg

Symptomatic

Celiac Disease

Silent Celiac

Disease

Latent Celiac Disease

Genetic susceptibility: - DQ2, DQ8

Positive serology

Manifest

mucosal lesion

Normal

Mucosa

Gastrointestinal Manifestations

(“Classic”) Most common age of

presentation: 6-24 months

• Chronic or recurrent diarrhea

• Abdominal distension

• Anorexia

• Failure to thrive or weight loss

• Abdominal pain

• Vomiting

• Constipation

• Irritability

Rarely: Celiac crisis

Non Gastrointestinal

Manifestations

• Dermatitis Herpetiformis

• Dental enamel hypoplasia

of permanent teeth

• Osteopenia/Osteoporosis

• Short Stature

• Delayed Puberty

• Iron-deficient anemia

resistant to oral Fe

• Hepatitis

• Arthritis

• Epilepsy with occipital

calcifications

Most common age of presentation: older child to adult

Listed in descending order of strength of evidence

The Clinical Manifestations of Celiac Disease

are More Heterogeneous Than

Previously Appreciated

A. Fasano, N Engl J Med 2003;348:2568-70.

Diagnostic principles

• Confirm diagnosis before treating

– Diagnosis of Celiac Disease mandates a strict

gluten-free diet for life

• following the diet is not easy

• QOL implications

• Failure to treat has potential long term

adverse health consequences • increased morbidity and mortality

Diagnosis

Serological Tests

• Antigliadin antibodies (AGA)

• Anti-deamidated gliadin antibodies (AGA II or

DGP)

• Antiendomysial antibodies (EMA)

• Anti tissue transglutaminase antibodies (TTG)

– first generation (guinea pig protein)

– second generation (human recombinant)

• HLA typing

Antigliadin Antibodies

• Antibodies (IgG and IgA) to the gluten

protein in wheat, rye and barley

• Advantages

– relatively cheap & easy to perform

• Disadvantages

– poor sensitivity and specificity

Endomysial Antibody - EMA

• IgA based antibody against reticulin connective

tissue around smooth muscle fibers

• Advantages

– high sensitivity and specificity

• Disadvantages

– false negative in young children

– operator dependent

– expensive & time consuming

– false negative in IgA deficiency

Endomysial Antibody - EMA

Antibodies against the outer

layer of the smooth muscle

of monkey esophagus or

human umbilical cord

NEGATIVE POSITIVE

Tissue Transglutaminase - TTG

• IgA based antibody against tissue transglutaminase (Celiac Disease autoantigen)

• Advantages

– high sensitivity and specificity (human TTG)

– non operator dependent (ELISA/RIA)

– relatively cheap

• Disadvantages

– false negative in young children

– false negative in IgA deficiency

– possibly less specific than EMA

Deamidated Gliadin (AGA II): Differences in Sensibility Based on the

Degree of Intestinal Atrophy

Rashtak S. and al. Clin Gastroenterol Hepatol 2008;6:426-444.

Deamidated Gliadin (AGA II): Differences in Sensibility Following

Implementation of a Gluten Free Diet

Rashtak S. and al. Clin Gastroenterol Hepatol 2008;6:426-444.

Serological Test Comparison

Fasano & Catassi NEJM 2012;367:2419-26

Hill I et al. J Ped Gastroenterol Nutr 2005

Diagnostic Approach: Symptomatic Patients

Asymptomatic Patients in at-risk groups

Hill I et al. J Ped Gastroenterol Nutr 2005

HLA Tests

Schuppan. Gastroenterology 2000;119:234

Kaukinen. Am J Gastroenterol 2002;97:695

HLA alleles associated with Celiac Disease

• DQ2 found in 95% of celiac patients

• DQ8 found in remaining patients

• DQ2 found in ~30% of general population

Value of HLA testing

• High negative predictive value

– Negativity for DQ2/DQ8 excludes diagnosis of

Celiac Disease with 99% confidence

HLA Tests

• Potential role for DQ2/DQ8

• asymptomatic relatives

• Down, Turner & Williams syndrome

• type 1 diabetes

• diagnostic dilemmas

Epidemiology The “old” Celiac Disease Epidemiology:

• A rare disorder typical of infancy

• Wide incidence fluctuates in space (1/400 Ireland

to 1/10000 Denmark) and in time

• A disease of essentially European origin

Diagnostic

Developments

CD Epidemiology

Milestones

1970

1980

1990

2000

AGA

EMA

Human TTG

1970

1980

1990

2000

Screening in blood donors (Sweden)

Screening in healthy population (Italy)

Screening in developing countries (W Sahara)

Screening in the US

Quick TTG

HLA on a drop of whole blood 2005 2005

Quick Screening in

Developing Countries

(Lybia, Egypt, Iran)

2006 Deamidated gliadin

1960 1970 1980 1990 2000 20100.0

0.5

1.0

1.5

year

CD

pre

vale

nce (

%)

C. Catassi et al, Annal Med 2010;42:530-8.

During the past 35 years the true prevalence of CD in USA

doubled every 15 years.

0.21%

0.45%

0.93%

Autoimmunity Epidemics:

Celiac Disease

The Epidemics Of Celiac Disease: Which Additional Factors are

Driving this Epidemics?

- Quality of gluten;

- Quantity of gluten;

- Breast Feeding;

- Timing of gluten introduction

- Maturity of gut functions influencing Ag trafficking and

handling:

- GALT

- PRRs

- Mucous production

- Barrier function

- Changes in microbiome composition.

Published on October 2, 2014 (today)

Published on October 2, 2014 (today)

Home Take Messages • Window of tolerance concept not supported anymore;

• Breast feeding in general or introduction of gluten while breast feeding

showed no protective effect on CD onset in at-risk infants;

• Early introduction (16 weeks) of gluten traces to potentially induce

tolerance did not protect against CD in at-risk infants;

• Delaying the introduction of gluten in at-risk infants does not prevent

CD but merely postpones its onset by approximately 8 months

(significant difference at 2 years FU that disappeared by 5 years FU);

• GI infections during the first year of life seems not influential in

increased the risk of CD onset;

• High-risk HLA profiles seems to be the most influential factor predictor

of increased risk of CD onset;

• The high prevalence of CD among the study cohort suggests that the

CD epidemics continues.

Diagnosis:

The Future to Come •Diagnostic algorithms to avoid

intestinal biopsy;

•Biomarkers to predict onset of

celiac disease in genetically

susceptible individuals;

•Host-intestinal microbiome

interaction;

•Pharmacometabonomics.

The 4 out of 5 Signs Rule

1. Presence of signs or symptoms compatible with CD;

2. Positive serology (TTG +/- EMA);

3. Compatible HLA (DQ2 e/o DQ8 positive);

4. Positive intestinal biopsy (enteropathy typical of CD);

5. Resolution of symptoms following implementation of a gluten free diet