HLA-DQ2-negative celiac disease in Finland and Spain

Murine MHC-Deficient Nonobese Diabetic Mice Carrying Human HLA-DQ8 Develop Severe Myocarditis and Myositis in Response to Anti-PD-1 Immune Checkpoint Inhibitor Cancer Therapy

Myocarditis has emerged as an immune-related adverse event of immune checkpoint inhibitor (ICI) cancer therapy associated with significant mortality. To ensure patients continue to safely benefit from life-saving cancer therapy, an understanding of fundamental immunological phenomena underlying ICI myocarditis is essential. We recently developed the NOD-cMHCI/II-/-.DQ8 mouse model that spontaneously develops myocarditis with lower mortality than observed in previous HLA-DQ8 NOD mouse strains. Our strain was rendered murine MHC class I and II deficient using CRISPR/Cas9 technology, making it a genetically clean platform for dissecting CD4+ T cell-mediated myocarditis in the absence of classically selected CD8+ T cells. These mice are highly susceptible to myocarditis and acute heart failure following anti-PD-1 ICI-induced treatment. Additionally, anti-PD-1 administration accelerates skeletal muscle myositis. Using histology, flow cytometry, adoptive transfers, and RNA sequencing analyses, we performed a thorough characterization of cardiac and skeletal muscle T cells, identifying shared and unique characteristics of both populations. Taken together, this report details a mouse model with features of a rare, but highly lethal clinical presentation of overlapping myocarditis and myositis following ICI therapy. This study sheds light on underlying immunological mechanisms in ICI myocarditis and provides the basis for further detailed analyses of diagnostic and therapeutic strategies.

Human adaptations to diet: Biological and cultural coevolution

Modern humans evolved in Africa some 200,000 years ago, and since then, human populations have expanded and diversified to occupy a broad range of habitats and use different subsistence modes. This has resulted in different adaptations, such as differential responses to diseases and different abilities to digest or tolerate certain foods. The shift from a subsistence strategy based on hunting and gathering during the Palaeolithic to a lifestyle based on the consumption of domesticated animals and plants in the Neolithic can be considered one of the most important dietary transitions of Homo sapiens. In this text, we review four examples of gene-culture coevolution: (i) the persistence of the enzyme lactase after weaning, which allows the digestion of milk in adulthood, related to the emergence of dairy farming during the Neolithic; (ii) the population differences in alcohol susceptibility, in particular the ethanol intolerance of Asian populations due to the increased accumulation of the toxic acetaldehyde, related to the spread of rice domestication; (iii) the maintenance of gluten intolerance (celiac disease) with the subsequent reduced fitness of its sufferers, related to the emergence of agriculture and (iv) the considerable variation in the biosynthetic pathway of long-chain polyunsaturated fatty acids in native populations with extreme diets.

Extra-intestinal manifestations of Celiac disease in children: their prevalence and association with human leukocyte antigens and pathological and laboratory evaluations

BACKGROUND

Celiac disease (CD) is an autoimmune disease caused by gluten intake. Traditionally CD was believed to be a disease of the gut, although a wide range of extra-intestinal manifestations (EIM) was recognized. The exact prevalence of EIM and the associated risk factors have not been well studied.

AIM

We aimed to assess the prevalence of EIM in children with CD and their association with human leukocyte antigen (HLA) typing, and pathological and laboratory indices.

METHOD

We conducted a cross-sectional study on children and adolescents with a definite diagnosis of CD. They were followed in the main Celiac Clinic of Southern Iran.

RESULTS

We included 204 children who were visited between 2012 and 2017. Nearly 85% of them were positive for HLA-DQ2 and 40.6% for HLA-DQ8. The most prevalent intestinal complaints reported were abdominal pain (42.6%) and chronic constipation (19.1%). Failure-to-thrive (32.7%), iron deficiency anemia (25%), short stature (20.5%), and eczema (18.6%) were the most common EIMs. However, failure-to-thrive and short stature were presented at significantly younger ages, whereas those patients with concomitant type 1 diabetes mellitus (DM) were significantly older. We also found significant relationships between autoimmune thyroid disease and HLA-DQ5, and the presence of headaches with HLA-DQ7. The prevalence of HLA types of DQ2, DQ8, DQ6, and DQ7 significantly varied among different Marsh groups. Patients who were positive for HLA-DQ8, were significantly older, taller, and weightier. No significant association was found between HLA types and any of the gastrointestinal symptoms, anti-tTG and compliance to gluten free diet. Moreover, there were no statistically significant differences detected between the presence of each individual EIM, the level of IgA anti-tTG, sex, and Marsh typing.

CONCLUSION

This study highlights the presence of EIM in CD and their associated factors. We show the potential role of HLA typing in some EIMs, which may shed light for future studies.

Frequency of celiac disease and distribution of HLA-DQ2/DQ8 haplotypes among siblings of children with celiac disease

BACKGROUND

Celiac disease (CD) is a multifactorial disease, but genetic factors play a major role in its etiology. It has been known that human leucocyte antigen (HLA)-DQ2/DQ8 haplotypes are one of the most important predisposing genetic factors. The risk of developing CD in first-degree relatives and especially siblings of celiac patients is quite high because of having the same HLA haplotypes.

AIM

To evaluate the frequency of CD and the distribution of the HLA-DQ2/DQ8 haplotypes in siblings of celiac patients.

METHODS

Patients with biopsy-proven CD and their siblings were included in the study; those who did not have HLA genotyping were excluded from the study. All siblings were on a gluten-containing diet. The HLA genotyping, tissue transglutaminase antibody IgA antibody test, and total IgA test were performed in all participants.

RESULTS

A total of 57 celiac patients and their 112 siblings were included in the study. The mean age of celiac patients and siblings were 10.30 ± 3.87 years and 9.90 ± 6.11 years, respectively. HLA-DQ2/DQ8 alleles were detected in 98.2% of patients with CD and 90.2% of siblings of celiac patients. HLA-DQ genotypes were present in all siblings diagnosed with CD. Tissue transglutaminase antibody IgA test was found to be positive in 16 siblings. CD was diagnosed in 12 siblings (10.7%) by intestinal biopsy.

CONCLUSION

The prevalence of CD was found to be 10.7% in siblings of celiac patients in our study. One-third of the siblings diagnosed with CD were asymptomatic. We detected HLA-DQ alleles in 98.2% of celiac patients and 100% in siblings diagnosed with CD. In addition, 1 of the 2 siblings was diagnosed with CD 1 year later and the other 4 years later. Therefore, we suggest that siblings of celiac patients should be followed up with clinical findings as well as HLA analysis and serological examination. Since the risk of developing CD is much higher in asymptomatic siblings, we recommend that siblings should be screened for CD even if they are asymptomatic.

Development of a Sequence Searchable Database of Celiac Disease-Associated Peptides and Proteins for Risk Assessment of Novel Food Proteins

Celiac disease (CeD) is an autoimmune enteropathy induced by prolamin and glutelin proteins in wheat, barley, rye, and triticale recognized by genetically restricted major histocompatibility (MHC) receptors. Patients with CeD must avoid consuming these proteins. Regulators in Europe and the United States expect an evaluation of CeD risks from proteins in genetically modified (GM) crops or novel foods for wheat-related proteins. Our database includes evidence-based causative peptides and proteins and two amino acid sequence comparison tools for CeD risk assessment. Sequence entries are based on the review of published studies of specific gluten-reactive T cell activation or intestinal epithelial toxicity. The initial database in 2012 was updated in 2018 and 2022. The current database holds 1,041 causative peptides and 76 representative proteins. The FASTA sequence comparison of 76 representative CeD proteins provides an insurance for possible unreported epitopes. Validation was conducted using protein homologs from Pooideae and non-Pooideae monocots, dicots, and non-plant proteins. Criteria for minimum percent identity and maximum E-scores are guidelines. Exact matches to any of the 1,041 peptides suggest risks, while FASTA alignment to the 76 CeD proteins suggests possible risks. Matched proteins should be tested further by CeD-specific CD4/8+ T cell assays or in vivo challenges before their use in foods.

HLA-DQ genotypes relative risks for celiac disease in Arabs: A case-control study

OBJECTIVES

It remains unknown what degree of risk is conferred by celiac disease (CD)-predisposing human leukocyte antigen (HLA)-DQ genotypes in Saudi Arabia compared with in Western countries. In this study, we aimed to determine the CD risk gradient associated with the HLA-DQ genotypes and to compare HLA-DQ genotypes between symptomatic patients with CD and screening-identified asymptomatic CD patients.

METHODS

We enrolled three groups of subjects, including 46 CD children diagnosed consecutively over the past 10 years, 54 CD children diagnosed during a mass screening of schoolchildren, and 192 healthy controls. All the participants were typed for the HLA-DQA1 and HLA-DQB1 genes by polymerase chain reaction sequence-specific oligonucleotide probes.

RESULTS

Comparing the patients with CD to controls, we identified 5 groups in the CD risk gradient: (i) very high risk associated with the DQ2.5/DQ8 genotype (odds ratio [OR] 46.93); (ii) high risk (homozygous DQ2.5, DQ2.5/DQ2.2; OR 4.12-5.04); (iii) intermediate risk (heterozygous DQ2.5, DQ8/DQ2.2; OR 1.61 and 1.67); (iv) low risk (DQ8, DQ2.2); and (v) very low risk (DQ2.x, DQX.5, DQX.x). Heterozygous DQ8 was more common in screening-identified group compared to symptomatic patients (13.0% vs 2.2%); however, other genotypes were very similar between the two groups.

CONCLUSION

The highest risk of developing CD in our Saudi Arabia population is associated with the DQ2.5/DQ8 genotype.

Frequency of HLA-DQ, susceptibility genotypes for celiac disease, in Brazilian newborns

Background

The frequency of HLA‐DQ2 and DQ8 predisposing genotypes for celiac disease (CD) has shown significant variation among different world regions and has not been previously determined among the highly interbred Brazilian population. The aim of this study was to investigate the frequency of these genotypes among Brazilian newborns (NB).

Methods

We typed DQA1*05 ‐ DQB1*02 (DQ2.5) and DQA1*03 ‐ DQB1*03:02 (DQ8) alleles in 329 NB using qPCR technique. Subsequently we confirmed our results by PCR‐SSP using a reference kit which further identified DQ2.2 (DQA1*02:01 ‐ DQB1*02).

Results

Among the 329 NB, using qPCR technique: 5 (1.52%) carried both DQ2.5 and DQ8 variants; 58 (17.63%) carried only DQ2.5 (DQA1*05 and DQB1*02) and 47 (14.29%) carried only the DQ8 (DQA1*03 and DQB1*03:02) variant. The use of the PCR‐SSP method yielded further information; among the 329 samples: 34 (10.34%) tested positive for DQ2.2 and among the 47 previously DQ8 positives samples, we found 10 (3.04%) that also tested positives for DQ2.2.

Conclusion

43.7% of the analyzed individual tested positive for at least one of the CD predisposing HLA‐DQ genotypes in our group of Brazilian NB. The highest frequency was found for DQ2.5 positive subjects (17.6%) followed by DQ8 (11.3%); DQ2.2 (10.3%); DQ8 and DQ2.2 (3.0%); DQ2.5 and DQ8 (1.5%). We found no positive sample for DQ2.5 associated with DQ2.2.

Risk variation in celiac disease in a population from Southern Spain: evaluating the influence of the DQB1*02:02 allele frequency

OBJECTIVES

To date, the greatest genetic risk factor known for celiac disease (CD) is the presence of HLA-DQ2 heterodimers, specifically DQ2.5 in state of homozygosis or heterozygosis. DQ2.2 variants are the second most important risk factor when carried trans to DQ2. This study aimed to determine the prevalence and risk genotypes of HLA-DR-DQ.

MATERIAL AND METHODS

A total of 196 patients with CD and 206 healthy controls from the Province of Málaga (southern Spain) were included. The corresponding risk gradient in our population was established in accordance with the odds ratios (ORs) found.

RESULTS

The heterozygous genotype for DR7-DQ2.2/DR3-DQ2.5 presented the highest risk (OR =6.404, p = .0001) followed by the DR3-DQ2.5 homozygous genotype (OR =4.721, p = .001). An intermediate risk was found for the DQ2.5 heterozygous genotype with no other DQ risk variant (DQ8 or DQ2.2). Similarly, these three genotypes had also an increase in the risk of associated-autoimmune diseases. The DQB1*02:01 allele was the most widely represented among patients with CD respect to the control group (f = 0.479, p = .0001), with the second most common being DQB1*02:02 (f = 0.209, p = .0001).

CONCLUSIONS

In addition to the gene dosage effect confirmed in our report, and in contrast with previous studies, we found a raised risk for those patients with DQ2.2 heterodimers in trans configuration to DQ2.5 compared to DQ2.5 homozygous individuals. Therefore, in our population of patients with CD the frequency of DQ2.2 acts as a factor that increases the genetic risk of developing CD.

HLA-DQ2 and -DQ8 haplotypes frequency and diagnostic utility in celiac disease patients of Gaza strip, Palestine

Purpose

Celiac disease (CD) diagnosis can be established by serological and small bowel biopsy (SBB), while absence of HLA-DQ2 and -DQ8 haplotypes excludes the disease. The present study aims at evaluating the diagnosis of a representative sample of pediatric and adult CD patients of Gaza strip in light of DQ2 and DQ8 haplotypes expression.

Methods

Unrelated CD patients (n = 101) and matched healthy controls (n = 97) were genotyped for DQA1*05, DQB1*02 and DQB1*03:02 alleles by allele-specific real-time PCR. The diagnosis was re-evaluated according to the patient laboratory tests and HLA-DQ genotype.

Results

The diagnosis of 35 patients who have been managed for CD could not be confirmed. Twenty-five of them were diagnosed upon their clinical presentation only. The remaining were either negative for serological and SBB tests or negative for HLA-DQ haplotypes. The HLA-DQ alleles were negative in 4 SBB and one Anti-EMA positive patients. The frequency of DQ2 and DQ8 haplotypes among the remaining 65 confirmed cases was 70.8 and 15.4%, respectively, compared to 17.5 and 27.8% in the controls. The DQB1*02 allele was the most common in the cases (84.6%) followed by DQA1*05 allele (80%) and DQB1*03:02 allele (20%). The DQA1*05 allele was commonest in the control group (54.6%) followed by DQB1*02 allele (42.3%) and DQB1*03:02 allele (28.9%).

Conclusions

Absence of HLA-DQ2 and HLA-DQ8 genotyping in the workup of patients may result in CD misdiagnosis, particularly in a setting with poor histopathological diagnostic capacity.

The long and winding road to IgA deficiency: causes and consequences

INTRODUCTION

The most common humoral immunodeficiency is IgA deficiency. One of the first papers addressing the cellular and molecular mechanisms underlying IgA deficiency indicated that immature IgA-positive B-lymphocytes are present in these patients. This suggests that the genetic background for IgA is still intact and that class switching can take place. At this moment, it cannot be ruled out that genetic as well as environmental factors are involved. Areas covered: A clinical presentation, the biological functions of IgA, and the management of IgA deficiency are reviewed. In some IgA deficient patients, a relationship with a loss-of-function mutation in the TACI (transmembrane activator and calcium-modulating cyclophilin ligand interaction) gene has been found. Many other genes also have been associated. Gut microbiota are an important environmental trigger for IgA synthesis. Expert commentary: Expression of IgA deficiency is due to both genetic and environmental factors and a role for gut microbiota cannot be excluded.

Double-Blind Randomized Clinical Trial: Gluten versus Placebo Rechallenge in Patients with Lymphocytic Enteritis and Suspected Celiac Disease

BACKGROUND

The role of gluten as a trigger of symptoms in non-coeliac gluten sensitivity has been questioned.

AIM

To demonstrate that gluten is the trigger of symptoms in a subgroup of patients fulfilling the diagnostic criteria for non-coeliac gluten sensitivity (NCGS), which presented with lymphocytic enteritis, positive celiac genetics and negative celiac serology.

METHODS

Double-blind randomized clinical trial of gluten vs placebo rechallenge.

INCLUSION CRITERIA

>18 years of age, HLA-DQ2/8+, negative coeliac serology and gluten-dependent lymphocytic enteritis, and GI symptoms, with clinical and histological remission at inclusion. Eighteen patients were randomised: 11 gluten (20 g/day) and 7 placebo. Clinical symptoms, quality of life (GIQLI), and presence of gamma/delta+ cells and transglutaminase deposits were evaluated.

RESULTS

91% of patients had clinical relapse during gluten challenge versus 28.5% after placebo (p = 0.01). Clinical scores and GIQLI worsened after gluten but not after placebo (p<0.01). The presence of coeliac tissue markers at baseline biopsy on a gluten-free diet allowed classifying 9 out of the 18 (50%) patients as having probable 'coeliac lite' disease.

CONCLUSION

This proof-of-concept study indicates that gluten is the trigger of symptoms in a subgroup of patients fulfilling the diagnostic criteria for NCGS. They were characterized by positive celiac genetics, lymphocytic enteritis, and clinical and histological remission after a gluten-free diet.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02472704.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Allele and haplotype frequencies for HLA-DQ in Iranian celiac disease patients

AIM: To assess the distribution of human leukocyte antigen (HLA)-DQ2 and -DQ8 in Iranian celiac disease (CD) patients and compare them to healthy Iranian controls.

METHODS: To predict the HLA-DQA1 and -DQB1 genes, we used six previously reported HLA-tagging single nucleotide polymorphism to determine HLA genotypes in 59 Iranian patients with ‘biopsy-confirmed’ CD and in 151 healthy Iranian individuals. To test the transferability of the method, 50 cases and controls were also typed using a commercial kit that identifies individual carriers of DQ2, DQ7 and DQ8 alleles.

RESULTS: In this pilot study 97% of CD cases (n = 57) and 58% of controls (n = 87) were carriers of HLA-DQ2 and/or HLA-DQ8 heterodimers, either in the homozygous or heterozygous state. The HLA-DQ pattern of these 57 CD patients: heterozygous DQ2.2 (n = 14) and homozygous DQ2.2 (n = 1), heterozygous DQ2.5 (n = 33) and homozygous DQ2.5 (n = 8), heterozygous DQ8 (n = 13) and homozygous DQ8 (n = 2). Two CD patients were negative for both DQ2 and DQ8 (3%).

CONCLUSION: The prevalence of DQ8 in our CD population was higher than that reported in other populations (25.4%). As reported in other populations, our results underline the primary importance of HLA-DQ alleles in the Iranian population’s susceptibility to CD.

Human leukocyte antigen DQ2.2 and celiac disease

Patients with celiac disease (CD) lacking both human leukocyte antigen (HLA)-DQ2.5 in cis (DQA1*05:01, DQB1*02:01) or trans (DQA1*05:05, DQB1*02:02) configuration and HLA-DQ8 (DQA1*03:01, DQB1*03:02) are considered to be rare. Therefore, absence of these genotypes is commonly used to exclude the diagnosis of CD. To investigate whether this approach is justified, the HLA-distribution in 155 children with CD was studied. A total of 139 (89.7%) patients carried HLA-DQ2.5. Of the remaining patients, 7 (4.5%) carried HLA-DQ8. Interestingly, the 9 (5.8%) patients lacking HLA-DQ2.5 and HLA-DQ8 carried HLA-DQA1*02:01 and -DQB1*02:02 (HLA-DQ2.2). Therefore, HLA-DQ2.2 should be included as an important HLA-type related to CD.

Association analysis of the extended MHC region in celiac disease implicates multiple independent susceptibility loci

Celiac disease is a common autoimmune disease caused by sensitivity to the dietary protein gluten. Forty loci have been implicated in the disease. All disease loci have been characterized as low-penetrance, with the exception of the high-risk genotypes in the HLA-DQA1 and HLA-DQB1 genes, which are necessary but not sufficient to cause the disease. The very strong effects from the known HLA loci and the genetically complex nature of the major histocompatibility complex (MHC) have precluded a thorough investigation of the region. The purpose of this study was to test the hypothesis that additional celiac disease loci exist within the extended MHC (xMHC). A set of 1898 SNPs was analyzed for association across the 7.6 Mb xMHC region in 1668 confirmed celiac disease cases and 517 unaffected controls. Conditional recursive partitioning was used to create an informative indicator of the known HLA-DQA1 and HLA-DQB1 high-risk genotypes that was included in the association analysis to account for their effects. A linkage disequilibrium-based grouping procedure was utilized to estimate the number of independent celiac disease loci present in the xMHC after accounting for the known effects. There was significant statistical evidence for four new independent celiac disease loci within the classic MHC region. This study is the first comprehensive association analysis of the xMHC in celiac disease that specifically accounts for the known HLA disease genotypes and the genetic complexity of the region.

T-cell response to gluten in patients with HLA-DQ2.2 reveals requirement of peptide-MHC stability in celiac disease

BACKGROUND & AIMS

Celiac disease is a diet-induced, T cell-mediated enteropathy. The HLA variant DQ2.5 increases risk of the disease, and the homologous DQ2.2 confers a lower level of risk. As many as 5% of patients with celiac disease carry DQ2.2 without any other risk alleles. Epitopes commonly recognized by T cells of patients with HLA-DQ2.5 bind stably to DQ2.5 but unstably to DQ2.2. We investigated the response to gluten in patients with HLA-DQ2.2.

METHODS

We generated intestinal T-cell lines and clones from 7 patients with HLA-DQ2.2 (but not DQ2.5) and characterized the responses of the cells to gluten. The epitope off-rate was evaluated by gel filtration and T cell-based assays. Peptide binding to DQ2.2 was studied with peptide substitutes and DQ2 mutants.

RESULTS

Patients with DQ2.2 and no other risk alleles had gluten-reactive T cells that did not respond to the common DQ2.5-restricted T-cell epitopes. Instead, many of the T cells responded to a distinct epitope that was not recognized by those from patients with HLA-DQ2.5. This immunodominant epitope bound stably to DQ2.2. A serine residue at P3 was required for the stable binding. The effect of this residue related to a polymorphism at DQα22 that was previously shown to determine stable binding of peptides to DQ2.5.

CONCLUSIONS

High levels of kinetic stability of peptide-major histocompatibility complexes are required to generate T-cell responses to gluten in celiac disease; the lower risk from DQ2.2 relates to constraints imposed on gluten peptides to stably bind this HLA molecule. These observations increase our understanding of the role of the major histocompatibility complex in determining T-cell responses in patients with celiac disease and are important for peptide-based vaccination strategies.

Serologic screening and genetic testing among brazilian patients with celiac disease and their first degree relatives

CONTEXT

Celiac disease susceptibility has been shown to be associated with the HLA alleles DQA1*0501 and DQB1*0201 (together encoding the DQ2 heterodimer) that are present in practically all celiac disease patients. The DQ8 heterodimer (coded by DQA1*03-DQB1*0302), which is carried on a DRB1*04 (DR4) haplotype, is commonly encoded for by the few celiacs who do not carry the DQ2 heterodimer. Only a few celiac disease patients have been reported without these known risk alleles.

OBJECTIVE

To assess the prevalence of celiac disease in a group of first degree relatives of celiac patients, and the frequency of HLA predisposing alleles both in the group of celiac patients and in their first degree relatives, identifying those first degree relatives who would need further screening for celiac disease.

METHODS

Ninety celiac disease patients and 207 first degree relatives underwent serologic screening for celiac disease (endomysial and transglutaminase antibodies) followed by intestinal biopsy in positive patients. The HLA-DQA1*0501, DQB1*0201 and DRB1*04 frequencies of celiac patients and their first degree relatives were determined utilizing the PCR method.

RESULTS

All the celiac disease patients (n = 90) with the exception of one (1.1%) carried at least one of the alleles investigated. Altogether 11 (5.3%) of the investigated first degree relatives did not carry any of the alleles studied. Fourteen (6.7%) new cases of celiac disease were found among the 207 celiac disease patients first degree relatives.

CONCLUSIONS

Considering the cost-benefit of the HLA typing of all the first degree relatives of celiac patients, their HLA status should be decided on an individual basis, taking account of their profile and preferences, and the existence of other medical conditions.

The incidence and clinical spectrum of refractory celiac disease in a north american referral center

OBJECTIVES

Refractory celiac disease (RCD) is one of the most serious causes of persistent symptoms in patients with celiac disease (CD). Published reports suggest that approximately half of patients in Europe are RCD type II, which carries a poor prognosis with a 5-year survival rate of ~50% compared with ~90% for RCD type I. However, disease patterns may be different in North America. The aim of this study was to explore the clinical spectrum of RCD in a North American population.

METHODS

Medical records of patients with biopsy-proven CD presenting to our institution were reviewed for a diagnosis of RCD. Demographic data, clinical characteristics, and mortality were evaluated and compared with our general CD population.

RESULTS

In all, 34 out of 844 (4.0%) CD patients had RCD. The cumulative incidence of RCD for patients diagnosed with CD at our center was 1.5%. Unintentional weight loss at diagnosis of RCD was found in 76.5% (n=26) compared with 16.7% (n=141) at diagnosis of CD (P<0.0001) and diarrhea at diagnosis of RCD was found in 79.4% (n=27) compared with 40.5% (342) at diagnosis of CD (P<0.0001). Five patients (14.7%) were diagnosed with RCD type II and of these, two died of enteropathy-associated lymphoma within 24 months of diagnosis of CD (observed mortality rate 5.9%).

CONCLUSIONS

Although RCD is a serious condition with significant morbidity; the observed mortality rates are low in our population. This study suggests that RCD may be less severe in North American vs. European populations.

Frequency of HLA-DQA1*0501 and DQB1*0201 alleles in patients with coeliac disease, their first-degree relatives and controls in Jordan

BACKGROUND

The primary genetic marker associated with coeliac disease (CD) is the HLA-DQ2 molecule, encoded by the DQA1*0501 and DQB1*0201 genes.

AIM

To investigate the frequency of HLA-DQA1*0501 and DQB1*0201 alleles in Jordanian patients with CD and their first-degree relatives.

METHODS

An allele-specific DNA-based PCR-sequence-specific primer was used to investigate DQA1*0501 and DQB1*0201 alleles in 44 CD patients, 47 first-degree relatives and 53 healthy controls.

RESULTS

The mean age of the patients at the time of diagnosis was 13.5 years (range 1-39) and at the time of the study was 19.3 years (range 5-42). The DQA1/B1 (0501; 0201) haplotype was present in 80% of patients and 66% of first-degree relatives compared with 32% of controls (p<0.0001 and <0.01, respectively). The remaining 20% of CD patients who were negative for the DQ2 molecule carried the DQB1*0201 allele only. A statistically significant difference was detected in the DQ2 hetero-dimer frequency between CD patients, their first-degree relatives and controls with a higher frequency in the patients group (p<0.001).

CONCLUSION

The significant differences in the frequency of DQA1*0501, DQB1*0201 alleles in CD patients and their first-degree relatives compared with the control group demonstrated the important role of these alleles in the development of CD in the Jordanian population.

Frequency distribution of HLA DQ2 and DQ8 in celiac patients and first-degree relatives in Recife, northeastern Brazil

AIMS

The aim of this study was to evaluate the frequencies of the HLA genotypes DQ2 and DQ8 and the alleles A1*05, A1*0201, B1*0201 and B1*0302 in individuals with celiac disease in Recife, northeastern Brazil.

METHODS

HLA DQ2 and DQ8 genotyping was performed for 73 individuals with celiac disease and 126 first-degree relatives with negative transglutaminase serology. The alleles DQA1*05, DQA1*0201, DQB1*02 and DQB1*0302 were identified by sequencing using specific primers and the EU-DQ kit from the Eurospital Laboratory, Trieste, Italy and double-checked by the All Set SPP kit (Dynal).

RESULTS

Among the 73 cases, 50 (68.5%) had the genotype DQ2, 13 (17.8%) had DQ8, 5 (6.8%) had DQ2 and DQ8, and 5 did not have any of these genotypes. Among the 5 negative individuals, four had the B1*02 allele and one did not have any of the alleles studied. B1*02 was the most frequent allele in both groups (94% in the patients and 89% in the control relatives).

CONCLUSIONS

In this study, celiac disease was associated with the genotypes DQ2 and DQ8. DQ2 predominated, but the distribution of the frequencies was different from what has been found in European populations and was closer to what has been found in the Americas. The high frequencies of the HLA genotypes DQ2 and DQ8 that were found in first-degree relatives would make it difficult to use these HLA genotypes for routine diagnosis of celiac disease in this group.

Enteropathy associated T-cell lymphoma and its precursor lesions

Enteropathy Associated T-cell Lymphoma (EATL) is an intestinal tumour of intra-epithelial lymphocytes. Based on morphology, immunohistochemistry and genetic profile EATL can be divided into two groups. EATL type I is a large cell lymphoma which is highly associated with Coeliac Disease (CD) and mostly presents with malabsorption, weight loss and CD-related symptoms. EATL type II consists of small to medium-sized cells and presents often with obstruction or perforation of the small bowel. This type of EATL has no known association with CD. When EATL has been diagnosed a thorough diagnostic work-up is needed. This work-up preferably includes video capsule enteroscopy (VCE), double-balloon enteroscopy (DBE), computed tomography (CT) combined with 18F-fluorodeoxyglucose positron emission tomography scan (18F-FDG-PET scan) if possible and magnetic resonance enteroclysis (MRE). Nowadays, most EATL patients are treated with chemotherapy mostly preceded by resection of the tumour and followed by stem cell transplantation. Despite these therapies outcome of EATL remains very poor with a 5-year survival of 8-20%. In order to improve survival prospective multicentre trials, studying new therapies are needed. The combination of chemotherapy, monoclonal antibodies and/or apoptosis inducing small molecules might be a potential treatment for EATL in the (nearby) future.

Cost-effective HLA typing with tagging SNPs predicts celiac disease risk haplotypes in the Finnish, Hungarian, and Italian populations

Human leukocyte antigen (HLA) genes, located on chromosome 6p21.3, have a crucial role in susceptibility to various autoimmune and inflammatory diseases, such as celiac disease and type 1 diabetes. Certain HLA heterodimers, namely DQ2 (encoded by the DQA1*05 and DQB1*02 alleles) and DQ8 (DQA1*03 and DQB1*0302), are necessary for the development of celiac disease. Traditional genotyping of HLA genes is laborious, time-consuming, and expensive. A novel HLA-genotyping method, using six HLA-tagging single-nucleotide polymorphisms (SNPs) and suitable for high-throughput approaches, was described recently. Our aim was to validate this method in the Finnish, Hungarian, and Italian populations. The six previously reported HLA-tagging SNPs were genotyped in patients with celiac disease and in healthy individuals from Finland, Hungary, and two distinct regions of Italy. The potential of this method was evaluated in analyzing how well the tag SNP results correlate with the HLA genotypes previously determined using traditional HLA-typing methods. Using the tagging SNP method, it is possible to determine the celiac disease risk haplotypes accurately in Finnish, Hungarian, and Italian populations, with specificity and sensitivity ranging from 95% to 100%. In addition, it predicts homozygosity and heterozygosity for a risk haplotype, allowing studies on genotypic risk effects. The method is transferable between populations and therefore suited for large-scale research studies and screening of celiac disease among high-risk individuals or at the population level.

HLA and autoimmune digestive disease: a clinically oriented review for gastroenterologists

OBJECTIVES

The human leukocyte antigen (HLA) system includes genes involved in graft-vs-host rejection and in immune response. The discovery that HLAs are associated with several diseases led to appealing developments both in basic biomedical research and in clinical medicine, and offered the opportunity to improve the understanding of pathogenesis and classification of diseases, as well as to provide diagnostic and prognostic indicators. The aim of this article is to review the association between HLA alleles and autoimmune digestive disease and its current relationship with modern HLA nomenclature and clinical practice.

METHODS

Articles dealing with the association between HLAs and autoimmune digestive disease (including celiac disease, inflammatory bowel disease, autoimmune hepatitis, sclerosing cholangitis and primary biliary cirrhosis) were searched for using Pubmed and SCOPUS databases from earliest records to January 2008.

RESULTS

The review has provided two sections. In the first, we explain the basic principles of HLA structure, function, and nomenclature, as an introduction to the second section, which describes current associations between HLA alleles and digestive diseases. The clinical implications of each HLA association are critically discussed. Actually, a clinical role for HLA typing is suggested for only a few conditions, e.g., celiac disease.

CONCLUSIONS

The knowledge of current HLA nomenclature and of its association with some digestive diseases such as celiac disease can be useful in clinical practice for diagnostic and prognostic purposes. This can avoid improper HLA typing as well as stressing the need for further studies on other possible clinical applications.

Systematic review: The evidence base for long-term management of coeliac disease

BACKGROUND

While gluten-free diet is an effective treatment for coeliac disease, the need for and goals of long-term management of patients are poorly defined.

AIM

To review systematically the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.

METHODS

Review of medical literature from 1975.

RESULTS

There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long-term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long-term management. Assessment of adherence to the gluten-free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non-invasive means are poor predictors of healing and the likelihood of complications.

CONCLUSION

Evidence (albeit limited) that adherence to a gluten-free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long-term strategy for follow-up is essential.

[Study of celiac disease in the pediatric population of Cantabria (Spain) and first-degree relatives]

BACKGROUND

Celiac disease (CD) is an autoimmune disease that affects genetically predisposed individuals. The HLA-DQ2 heterodimer is present in nearly 90% of patients while HLA-DQ8 is found in the remaining 10%.

AIM

To study the characteristics of CD in pediatric patients in Cantabria and their first-degree relatives, with special emphasis on factors related to haplotype, serology, and forms of clinical presentation.

PATIENTS AND METHODS

Eighty-six patients with CD and 215 first-degree relatives were HLA genotyped. Clinical, laboratory, immunologic, and histological data were obtained from all patients.

RESULTS

Clinical presentation was classical in 95% of the patients and mono-symptomatic in the remaining 5%. Anti-gliadin antibodies (AGA) and anti-transglutaminase antibodies (ATGA) were positive in 95% of the patients and negative in 5% (all with IgA deficiency). DQ2 was found in 71% of the patients (homozygotes or heterozygotes) and DQ8 was found in 9.5%. No heterodimers of risk were found in 22%. CD was found in six relatives (three were positive for AGA and four were positive for ATGA). Forty-nine percent of the relatives carried the DQ2 heterodimer and 15% the DQ8 heterodimer; no heterodimers of risk were found in 40%.

CONCLUSIONS

The most prevalent HLA found in patients with CD in the autonomous region of Cantabria was DQ2 (71%). This prevalence is clearly lower than that reported in other Spanish regions. The prevalence of CD among first-degree relatives was similar to that found in other studies performed in Spain (2.8%). Our data support the need for systematic study of the first-degree relatives of patients with CD.

Gluten tolerance in adult patients with celiac disease 20 years after diagnosis?

BACKGROUND AND OBJECTIVE

Celiac disease (CD) is believed to be a permanent intolerance to gluten. A number of patients, however, discontinue the gluten-free diet (GFD) without developing symptoms or signs. The aim of our study was to investigate whether CD patients are capable of developing tolerance to gluten.

METHODS

All 77 adult patients from our hospital known to have biopsy-proven CD for more than 10 years were invited to participate. We investigated symptoms, gluten consumption, antibodies for CD and other autoimmunity, human leukocyte antigen (HLA)-typing, bone mineral density, and performed small bowel biopsies. Tolerance was defined as no immunological or histological signs of CD while consuming gluten.

RESULTS

Sixty-six patients accepted participation, but after review of the diagnostic biopsies 53 were found to have true CD. Twenty-three percent of patients had a gluten-containing diet, 15% admitted gluten transgression and 62% followed the GFD. Patients on a GFD had significantly more osteoporosis. Normal small bowel mucosa was found in four of eight on gluten-containing diet and in four of four with gluten transgression. Two patients were considered to have developed tolerance to gluten. One of them was HLA-DQ2/DQ8 negative.

CONCLUSION

Development of tolerance to gluten seems possible in some patients with CD. Further follow-up will show whether this tolerance is permanent or only a long-term return to latency. This feature may be associated with genetic characteristics, especially with HLA genotypes that differ from DQ2 or DQ8. More insight into the mechanisms of the development of gluten tolerance may help to distinguish those CD patients that might not require life-long GFD.

Human leucocyte antigen and TNFalpha polymorphism association in microscopic colitis

OBJECTIVES

Coeliac disease (CD) is common in patients with microscopic colitis (MC). The human leucocyte antigen (HLA)-DR3-DQ2 haplotype is strongly associated with CD, and there is evidence for an association with MC. We analysed the genetic background of MC by assessing the haplotypes of HLA-DR3-DQ2 and HLA-DR4-DQ8. In addition, TNFalpha gene polymorphism (-308) associated with susceptibility to several autoimmune diseases was studied.

METHODS

Eighty patients with MC including 29 with collagenous colitis (CC) and 51 with lymphocytic colitis (LC) were typed for HLA-DR3-DQ2, and HLA-DR4-DQ8 molecule encoding genes using either an allele-specific PCR, or hybridization with sequence-specific oligonucleotides. Duodenal biopsies (N=78) confirmed the diagnosis of CD in 15 (18.8%) patients. TNFalpha(308) alleles were analyzed in 78 patients with MC (27 with CC and 51 with LC). A control group of 3627 patients was used in the HLA study and 178 patients in the TNFalpha study.

RESULTS

HLA-DR3-DQ2 haplotype was more frequent in patients with MC (43.8%) including both subgroups (LC, 44.8%; CC, 43.1%; P<0.001), and MC with CD (86.7%; P<0.001) and without CD (33.3%; P=0.003), compared with the controls (18.1%). Similarly, the TNF2 carrier rate was higher in MC (46.2%; P<0.001) including both CC (44.4%; P=0.031) and LC (47.1%; P=0.001), and both MC patients with CD (66.7%; P=0.001) and without CD (39.3%; P=0.019), compared with the controls (23%).

CONCLUSION

Both CC and LC are associated with the HLA-DR3-DQ2 haplotype and with TNF2 allele carriage. These associations are present also in MC patients without CD. The shared predisposing HLA-DR3-DQ2 haplotype and the high prevalence of CD in patients with MC suggest an epidemiological overlap, and probably some similarities in the pathogenesis of CD and MC.

Secretion of celiac disease autoantibodies after in vitro gliadin challenge is dependent on small-bowel mucosal transglutaminase 2-specific IgA deposits

Background

In celiac disease gluten, the disease-inducing toxic component in wheat, induces the secretion of autoantibodies which are targeted against transglutaminase 2 (TG2). These autoantibodies are produced in the small-intestinal mucosa, where they can be found deposited extracellularly below the epithelial basement membrane and around mucosal blood vessels. In addition, during gluten consumption these autoantibodies can also be detected in patients' serum but disappear from the circulation on a gluten-free diet. Interestingly, after adoption of a gluten-free diet the serum autoantibodies disappear from the circulation more rapidly than the small-intestinal mucosal autoantibody deposits. The toxicity of gluten and the secretion of the disease-specific autoantibodies have been widely studied in organ culture of small-intestinal biopsy samples, but results hitherto have been contradictory. Since the mucosal autoantibodies disappear slowly after a gluten-free diet, our aim was to establish whether autoantibody secretion to organ culture supernatants in treated celiac disease patient biopsies is related to the duration of the diet and further to the pre-existence of mucosal TG2-specific IgA deposits in the cultured biopsy samples.

Results

In the organ culture system conducted with biopsies derived from treated celiac disease patients, gliadin induced secretion of autoantibodies to culture supernatants, reduced epithelial cell height and increased the density of lamina proprial CD25+ cells. However, these changes could be demonstrated only in biopsies from short-term treated celiac disease patients, where the small-intestinal mucosal TG2-specific IgA autoantibody deposits were still present. Furthermore, in these biopsies autoantibody secretion could be stimulated fully only after a 48-hour gliadin challenge.

Conclusion

Our results show that studies focusing on the toxic effects of gliadin in the organ culture system should be carried out with biopsy samples from short-term treated celiac disease patients who are likely still to have mucosal IgA deposits present. In addition to providing an explanation for the discrepancies in previous publications, the present study also enables further validation of the organ culture method.

HLA genotyping is useful in the evaluation of the risk for coeliac disease in the 1st-degree relatives of patients with coeliac disease

OBJECTIVE

Coeliac disease (CD) is a common disease with a strong heredity. About 10-20% of 1st-degree relatives of probands develop CD. Relatives should be screened for CD, because if not treated, CD exposes patients to numerous complications. The heterogeneity of symptoms and the lifetime-spanning risk of CD render the timing of CD antibody and/or gastroscopy screenings difficult. As CD susceptibility has been shown to be strongly associated with the HLA alleles DQA1*0501 and DQB1*0201 (together encoding the DQ2 heterodimer) and DRB1*04 (associated with the DQ8 heterodimer), our aim was to investigate whether HLA genotyping might be useful in the identification of 1st-degree relatives of CD patients who do not need further screening for CD.

MATERIAL AND METHODS

The study comprised 54 Finnish CD families including 54 CD probands and 382 living 1st-degree relatives. All subjects who were willing to participate were screened for CD (duodenal and skin biopsies; endomysial, reticulin and gliadin antibodies). The DQA1*0501, DQB1*0201 and DRB1*04 allele frequencies of CD patients and the 1st-degree relatives were determined.

RESULTS

Altogether 17.6% (5.9% of the parents, 15.7% of the siblings, 25.8% of the offspring) of the investigated 1st-degree relatives (n = 245) did not carry any of the alleles studied. All of the CD patients (n = 136) with the exception of one (0.7%) carried at least one of the alleles investigated.

CONCLUSIONS

By using the HLA genotyping a considerable proportion of 1st-degree relatives of CD probands could be excluded from further screening for CD.

Immunoglobulin A autoantibodies against transglutaminase 2 in the small intestinal mucosa predict forthcoming coeliac disease

BACKGROUND

Reliable markers of early developing coeliac diseases are needed. Coeliac autoantibodies in the serum or Marsh I inflammation may be indicators of subsequent coeliac disease.

AIM

To investigate whether determination of intestinal transglutaminase 2-targeted autoantibody deposits would detect early developing coeliac disease better than previous methods.

METHODS

The study investigated patients previously excluded for coeliac disease: 25 had positive serum coeliac autoantibodies (endomysial), 25 antibody-negative had Marsh I, and 25 antibody-negative had Marsh 0 finding. Seven (median) years after baseline investigation, new coeliac cases were recorded, and small bowel biopsy was offered to the rest of the patients. Serum and intestinal coeliac autoantibodies and intraepithelial lymphocytes were assessed as indicators of developing coeliac disease.

RESULTS

Seventeen patients had developed coeliac disease: 13 in the autoantibody-positive group, three in the Marsh I group and one in the Marsh 0 group. At baseline, intestinal coeliac autoantibody deposits had a sensitivity and specificity of 93% and 93% in detecting subsequent coeliac disease, CD3+ 59% and 57%, gammadelta+ 76% and 60%, and villous tip intraepithelial lymphocytes 88% and 71%, respectively.

CONCLUSIONS

Endomysial antibodies with normal histology indicates early developing coeliac disease. Transglutaminase 2-targeted intestinal autoantibody deposits proved the best predictor of subsequent coeliac disease.

Human leukocyte antigen-DQ2 homozygosity and the development of refractory celiac disease and enteropathy-associated T-cell lymphoma

BACKGROUND & AIMS

Celiac disease (CD) is a common gluten-sensitive enteropathy associated with human leukocyte antigen (HLA)-DQ2 and HLA-DQ8. The aim of this study was to determine if a particular HLA-DQ subtype predisposes to complications such as refractory CD with (RCD II) or without aberrant T cells (RCD I), and enteropathy-associated T-cell lymphomas (EATL).

METHODS

Molecular HLA-DQ typing was performed on 43 RCD I, 43 RCD II, and 30 EATL patients, and compared with age-matched groups of 121 patients with histologically defined uncomplicated CD and 183 healthy controls. All individuals were Dutch Caucasians and were at least 21 years of age.

RESULTS

HLA-DQ2 was present in 79% of RCD I, 97.7% of RCD II, and 96.6% of EATL patients. The differences were significant when compared with 28.9% in controls but not with 91.7% in uncomplicated CD. Homozygosity for HLA-DQ2 was observed in 25.5% of RCD I, 44.1% of RCD II, and 53.3% of EATL patients vs 20.7% of uncomplicated CD patients and 2.1% of controls. HLA-DQ8 was present in 10.7% of CD, 16.2% of RCD I, 9.3% of RCD II, and 6.6% of EATL patients vs 20.2% of controls.

CONCLUSIONS

Homozygosity for HLA-DQ2 is associated with RCD II and EATL. Early identification of HLA-DQ2 homozygous CD patients may help to recognize CD patients at risk for developing these severe complications.

Predisposing HLA-DQ2 and HLA-DQ8 haplotypes of coeliac disease and associated enteropathy in microscopic colitis

OBJECTIVE

To assess the presence of both genetic and serological markers of coeliac disease in patients with microscopic colitis, and whether there was associated enteropathy.

METHODS

HLA-DQ2, HLA-DQ8, serum immunoglobulin A-antiendomysial and immunoglobulin A-anti-tissue transglutaminase antibodies were investigated in 59 patients with microscopic colitis. Seventy healthy subjects acted as the control group. Endoscopic biopsies from the distal duodenum were obtained in DQ2-positive or DQ8-positive patients. Patients with histological changes compatible with gluten-sensitive enteropathy were started on a gluten-free diet.

RESULTS

Seventeen of 70 (24.3%) healthy controls were DQ2-positive. Twelve of 25 (48%) patients with lymphocytic colitis (P = 0.027 versus controls), and 11 of 34 (32.3%) with collagenous colitis (P = 0.38 versus controls) were DQ2-positive. There were no differences in the frequency of DQ8-positivity. The coeliac serology was positive in one patient. Duodenal biopsies were performed in 23 DQ2-positive and/or DQ8-positive patients. None had villous atrophy (Marsh III lesion) (0%; 95% confidence interval, 0-6.1). A Marsh type I lesion was found in four patients. Three of these patients were put on a gluten-free diet with disappearance of diarrhoea.

CONCLUSIONS

The results suggest that there is an association of lymphocytic colitis with HLA-DQ2 genes, which might be relevant in the pathogenesis of this disease. The association of microscopic colitis with Marsh type III coeliac disease seems to be rare, making it unnecessary to routinely screen for coeliac disease in microscopic colitis patients.

Cribado de la enfermedad celíaca en grupos de riesgo

Several epidemiological studies show that celiac disease with extraintestinal manifestations is 15 times more frequent than celiac disease with intestinal symptoms. Fifteen years ago the iceberg model was proposed to explain the epidemiology of this disease. On the one hand, there are a quantifiable number of patients who are correctly diagnosed since they have symptoms suggestive of this disease and who form the visible part of the iceberg. However, several studies using screening serology demonstrate that for each patient diagnosed, there is a mean of 5-10 patients without a diagnosis. These patients form the submerged part of the iceberg (monosymptomatic or silent celiac disease). The most widely accepted strategy to investigate the submerged part of the "celiac iceberg" is screening of known risk groups through a systematic search for celiac disease in these groups.

Natural history of transglutaminase autoantibodies and mucosal changes in children carrying HLA-conferred celiac disease susceptibility

OBJECTIVE

The natural history of the appearance and fate of transglutaminase autoantibodies (TGAs) and mucosal changes in children carrying HLA-conferred celiac disease (CD) risk remains obscure. The aim of this study was to investigate the sequence of events leading to overt CD by retrospective analysis of TGA values in serum samples collected frequently from genetically susceptible children since birth or early childhood.

MATERIAL AND METHODS

A total of 1101 at-risk children were recruited in the study. A duodenal biopsy was recommended to all TGA-positive children and performed if parental consent was obtained.

RESULTS

During up to 8 years of follow-up, 35 of the cohort children developed TGAs, the youngest at age 1.3 years. After age 1.3 years the annual TGA seroconversion rate was constantly around 1% at least until age 6 years. However, 18 of the 35 TGA-positive children (51%) lost TGAs, without any dietary manipulation. A further 7 children were IgA deficient; of these children, 2 developed IgG antigliadin antibodies (IgG-AGA). Only 13 of the 21 children (62%) who had duodenal biopsies had villous atrophy. The time that passed since emergence of TGAs failed to predict the biopsy findings. Only one of the children with TGAs and both of the IgA-deficient children with IgG-AGA had noticeable abdominal symptoms.

CONCLUSIONS

TGAs appear in children at a constant rate after 1 year of age until at least the age of 6 years. Over half of the children loose TGA without gluten exclusion, challenging TGA positivity-based CD prevalence estimates. In symptom-free children, a requirement of two consecutive TGA-positive samples taken >or=3 months apart before performing a duodenal biopsy might diminish the number of unnecessary intestinal biopsies.

IL6, IL10 and TGFB1 gene polymorphisms in coeliac disease: differences between DQ2 positive and negative patients

Predisposition to coeliac disease (CD) might be partially due to an individual pattern of hyper-inflammatory biased immune response. One of these patterns of intense response may be linked to the haplotype carrying HLA-DQ2 alleles and TNF -308A allele. However, 10 % of CD patients do not express the DQ2 heterodimer and these do not usually carry the TNF -308A allele. A similar response might be achieved by genes codifying other cytokines.

OBJECTIVES

To study biallelic polymorphisms in genes codifying for TNFalpha, IL10, IL6 and TGFbeta1 in DQ2 negative CD patients and to compare the results with DQ2 positive patients and healthy controls, in order to establish whether any of these polymorphisms have a role in CD susceptibility.

METHODS

TNF -308 (G > A), IL-6 -174 (G > C) and TGFB1 codon 10 (+ 869, T > C) and codon 25 (+ 915, G > C) polymorphisms and IL-10 haplotype of polymorphisms in positions -1082 (G > A), -819 (C > T) and -592 (C > A) were typed by a SSP-PCR technique.

RESULTS

The distribution of allele frequencies for TNF -308 is different between DQ2 positive CD patients and controls and the same occurs for haplotype frequencies of the IL10 promoter (-1082, -819, -592): The frequencies of the TNF -308A allele (p = 0.027), TNF -308A carriers (p = 0.031) and of IL10GCC haplotype are increased (p = 0.013) in DQ2 positive CD patients. However, the IL6 -174 allele G is more frequent in DQ2 negative patients than in healthy controls (p = 0.018), DQ2 negative controls (p = 0,018), and DQ2 positive patients (p = 0.008).

CONCLUSIONS

DQ2 negative CD patients show an increased frequency of genotypes associated to IL6 high production. These were mainly allele G homozygous for the IL6 gene (-174) polymorphism. The IL6 -174GG genotype (homozygous) may be an additional risk marker for CD in DQ2 negative patients, representing an alternative susceptibility factor for CD when TNF -308A is negative.

Genetic testing: who should do the testing and what is the role of genetic testing in the setting of celiac disease?

Celiac disease is a remarkable and common immune-mediated disorder determined by both the presence of characteristic HLA alleles (DQ2 and DQ8) and one of the best characterized environmental factors (gliadin) for any common autoimmune disease. The discovery of transglutaminase autoantibodies and the development of assays for these antibodies has allowed the identification of a large number of asymptomatic individuals with autoimmunity and intestinal biopsy evidence of celiac lesions. Further understanding of the sequelae of asymptomatic celiac disease, and the interaction between genetic susceptibility and environmental factors, are likely to alter fundamentally both genetic screening for celiac disease and its therapy.

Cytokine Gene Polymorphisms and Genetic Association with Coeliac Disease in the Finnish Population

Coeliac disease (CD) is an intestinal disorder caused by intolerance to dietary gluten in susceptible individuals. The HLA-DQ genes are major risk factors for CD, but other genes also play an important role in the disease susceptibility. Immune-mediated mechanisms are known to underlie the pathogenesis of CD. We studied single-nucleotide polymorphisms in transforming growth factor (TGF)-beta1, interleukin (IL)-10, IL-6, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha genes in the Finnish population using family-based association approach. In addition, we genotyped a trinucleotide repeat polymorphism in the major histocompatibility complex (MHC) class I chain-related protein A (MICA) gene, located in the human leucocyte antigen (HLA) region in the vicinity of TNF-alpha. To control the effect of linkage disequilibrium between HLA-DQ genes and MICA and TNF-alpha, an HLA-stratified association analysis was performed. We did not find evidence of association between TGF-beta1, IL-10, IL-6 and IFN-gamma polymorphisms and CD susceptibility. No association was found for any of the MICA alleles independently of DQ genes, whereas TNF-alpha-308 A allele was slightly overrepresented on chromosomes carried by CD patients compared with control chromosomes, indicating that either TNF-alpha, or another gene in linkage disequilibrium with it, could confer increased susceptibility to CD. This result supports the earlier findings that the HLA region harbours a novel susceptibility factor in addition to HLA-DQ.

Allele and haplotype frequencies for HLA class II (DQA1 and DQB1) loci in patients with celiac disease from Spain

Celiac disease (CD) is a complex and multifactorial disease, defined as a malabsorptive disorder of the small intestine resulting from ingestion of gluten. Genetic susceptibility to CD has been associated with human leukocyte antigen (HLA)-DQ2 heterodimer, encoded by the DQA1*0501 and DQB1*02 genes. However, HLA risk factors do not explain the whole genetic predisposition: not all DQ2-encoding haplotypes confer equal susceptibility to CD. The aim of the present work was to confirm the aforementioned findings in a southern European population. With this purpose, 136 unrelated children diagnosed with CD were typed at the DNA level for HLA-DQA1 and -DQB1 loci. Patients are currently attended at the Donostia Hospital (province of Guipúzcoa, Spain). HLA class II typing was performed by polymerase chain reaction-sequence specific primer procedures. Conspicuous frequencies of the alleles associated with susceptibility to CD were observed (DQA1*0501: 0.592, DQB1*0201: 0.471). Accordingly, the haplotypes DQA1*0501-DQB1*0201 and DQA1*0201-DQB1*0202 revealed a strong linkage disequilibrium (18.84% and 18.75%, respectively) when compared with the Spanish general population. Of the total sample, 93.4% (127 individuals) were carriers of DQ2 heterodimer, either in homozygosis or in heterozygosis. This percentage coincides with figures reported in previous studies, implying the effect of other genes in the development of CD.

La maladie cœliaque de l’adulte : aspects nouveaux

INTRODUCTION

Celiac disease also known as gluten-sensitive enteropathy is a complex disorder where genetically susceptible individuals develop in typical cases signs of malabsorption after ingestion of cereals. Malabsorption is due to total or subtotal atrophy of the small intestinal mucosa regressing after adherence to a gluten-free diet. The only effective therapy is life-long strict abstinence from wheat, rye and barley.

CURRENT KNOWLEDGE AND KEY POINTS

During the last two decades spectrum of clinical features of adult celiac disease has been modified. About 60% of cases are now revealed by extraintestinal manifestations. Moreover, recent studies that used serological methods revealed existence of both latent and silent celiac sprue. The finding of the high frequency of atypical celiac sprue contributed to underestimation of the true prevalence of celiac disease until now, and explained that celiac disease could be unknown for a long time, with increased risk of nutritional deficiencies and malignancy. Concurrently, the finding that celiac disease is primarily associated to a few HLA class II molecules, and recent advent of tissue transglutaminase as the main auto-antigen eliciting anti-endomysial antibodies allowed to propose new pathogenesis hypothesis and efficient screening tests for celiac disease diagnosis.

FUTURE PROSPECTS AND PROJECTS

New epidemiological data concerning adult celiac disease must incite to a more systematic screening in patients with atypical but evocative features, or in at-risk subjects. Introduction of enzyme linked immunosorbent assays (ELISA) for the detection for anti-tissue transglutaminase antibodies allows to make use of a new available and efficient diagnosis parameter, which could constitute the main screening test in the near future.

Fluctuating transglutaminase autoantibodies are related to histologic features of celiac disease

BACKGROUND & AIMS

Asymptomatic children at risk for celiac disease (CD) and seropositive for immunoglobulin A anti-TG autoantibodies (TGAA) may lack small intestinal mucosal changes characteristic of CD. We have followed a group of children with serial testing for TGAA.

METHODS

Subjects were a group of at-risk children comprised of infants expressing HLA-DR3 on newborn screening, those with type 1A diabetes, or a first-degree relative of someone with type 1 diabetes. All children participating in the prospective study for development of CD underwent serial testing for TGAA. Data from clinical evaluation and small intestinal biopsy were compared to the TGAA levels followed over time.

RESULTS

In 42 children, serial TGAA determinations while on a gluten-containing diet showed levels fluctuating 10-100-fold over 3-12 months. A TGAA index more than 0.5 had a positive predictive value (PPV) for histologic confirmation of CD of 96% (22/23). A TGAA index above the usual cutoff for positivity (0.05) had a PPV of only 76% (28/37).

CONCLUSIONS

In children with TGAA seropositivity, the TGAA level varied over time and a higher titer predicted an abnormal biopsy characteristic of CD. A threshold for biopsy for diagnosis of CD could be set higher for screening-identified cases than for clinically identified cases to decrease the frequency of performing "normal" biopsies.