Clinical utility of celiac disease-associated HLA testing

Clinical settings in which human leukocyte antigen typing is still useful in the diagnosis of celiac disease

Celiac disease (CD) is a systemic autoimmune disorder triggered by gluten ingestion ingenetically predisposed individuals. It is characterized by intestinal histological damage and the production of specific autoantibodies. The latest European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) 2020 guidelines have excluded human leukocyte antigen (HLA) genotyping from the no-biopsy diagnostic approach due to its weak positive predictive value, limited availability, and high cost in some countries. However, HLA genetic testing remains valuable in certain clinical contexts. This study provided practical indications for when to request and how to interpret HLA genotyping, emphasizing its continued relevance for CD diagnosis in specific cases. We also proposed a strategy for monitoring the risk of developing type 1 diabetes (T1D) in patients with CD, based on the risk stratification carried by different HLA genotypes. A retrospective analysis of 746 patients with CD and 627 controls was conducted at our hospital starting in 2012, when HLA genotyping became mandatory for the diagnosis of CD. We identified key clinical scenarios where HLA testing remains useful. Several high risk HLA-DQ genotypes strongly associated with CD were highlighted, including HLA-DQ2.5/HLA-DQ2.2 and HLA-DQ2.5/HLA-DQ2.5. Notably, while the HLA-DQ2.5/HLA-DQ2.2 genotype is linked to CD, it appears to confer protection against T1D. To support clinical practice, we presented a table clarifying commonly used HLA terminology, and another summarized the main clinical situations in which HLA genotyping should still be considered. These findings underscore the dual role of HLA testing: Not only can it help rule out CD in selected cases, but it also identifies patients with CD at risk for T1D, guiding personalized monitoring strategies.

Typing of HLA susceptibility alleles as complementary tool in diagnosis of controversial cases of pediatric celiac disease

Objectives

Diagnosis of celiac disease (CeD), an immune-mediated disorder, is based on clinical presentation, a panel of serological markers, and the histopathological findings in duodenal biopsies. Commonly, pediatric CeD patients fulfill these criteria for diagnosis. However, lack of correlation between serology tests and histology, or no accessible biopsies because of clinical conditions or during the COVID pandemic, are conditions that led to inconclusive diagnoses. Since the majority of CeD patients carry HLA-DQ2 and/or DQ8 alleles, HLA testing is used as a complementary tool in diagnosis though is costly and not broadly available for gastroenterology centers.

Methods

We performed a retrospective study to assess the performance of HLA testing when applied to selected groups of patients who could not be definitely diagnosed following the common algorithm. Eighty patients underwent testing for CeD-related HLA-DQ2 and DQ8 alleles.

Results

HLA typing contributed to diagnosis in 34 patients with positive serology but normal mucosa or those who presented negative serology or slightly positive serology (less than 3 times ULN) and duodenal histopathological changes. In patients with normal histology and negative or slightly positive serology, or those who did not undergo intestinal biopsy (39 in total), HLA typing contributed to CeD diagnosis in 23 cases, only 16 patients were admitted for a clinical follow-up program.

Conclusion

HLA-DQ typing supported the diagnosis in 57 of 80 children (71.2%) with previously inconclusive results, providing a beneficial approach for diagnosing celiac disease (CeD) in selected cases.

Multicenter screening for ADHD among school-age pediatric patients with type 1 diabetes - study protocol

PURPOSE

Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental condition that affects approximately 5% of the pediatric population, with increased prevalence among those with type 1 diabetes (T1D). Reports suggest that unrecognized and untreated ADHD impairs T1D control and that ADHD may be underdiagnosed in the Polish population. The International Society for Pediatric and Adolescent Diabetes recommends neurodevelopmental assessments in children with T1D, but specific guidelines on procedures and implementation are lacking. Therefore, we designed a systemic screening protocol aimed at assessing the prevalence of ADHD among Polish children with T1D that could be utilized in clinical practice.

MATERIALS AND METHODS

The protocol for the study was approved by the Bioethical Committee at the Medical University of Lodz (RNN/280/21/KE). Participation is offered to all children aged 8-16 y.o. with T1D duration ≥1 year and without significant comorbidities (epilepsy, intellectual disability). The protocol includes a first-line procedure using the short version of the Conners 3 questionnaire and on-site structured consultation with a psychologist for those with increased risk of ADHD (utilizing detailed Conners 3 and MINI-Kid questionnaires), followed by a video consultation with a psychiatrist.

RESULTS

The screening was initiated between January and May 2023 and is ongoing in four Polish reference pediatric centers. These centers provide diabetes care to approximately 2,500 youth with T1D. Over 36 months, our goal is to assist in diagnosing ADHD in approximately 190 children.

CONCLUSIONS

Comorbidity of ADHD and T1D remains an unrecognized challenge for pediatric psychiatric and diabetes care, and there is a need for effective diagnostic protocols.

Longitudinal screening of HLA-risk and HLA-nonrisk children for celiac disease to age 15 years: CiPiS study

OBJECTIVES

Autoantibodies against tissue transglutaminase (tTG) are serological markers of celiac disease. The aim was to study the applicability of human leukocyte antigen (HLA)-genotyping and tTG autoantibodies in the screening of celiac disease in a longitudinal birth cohort followed to age 15 years.

METHODS

Included were 13,860 HLA-DQ-genotyped children at birth and previously invited to a screening at age 3 and 9 years, respectively. HLA-DQB1*02 and/or DQB1*03:02 (HLA-risk) children were compared with non-HLA-DQB1*02 and non-DQB1*03:02 (HLA-nonrisk) children. The present study reinvited 12,948/13,860 (93.4%) children at age 15 years of whom 1056/2374 (44.5%) participated in screening at both age 3 and 9 years. Both immunoglobulin A (IgA) and G (IgG) autoantibodies against tTG were analyzed separately in radiobinding assays. Persistently tTG autoantibody-positive children were examined with intestinal biopsy to confirm the diagnosis of celiac disease.

RESULTS

At age 3 years, celiac disease was diagnosed in 56/1635 (3.4%) HLA-risk children compared with 0/1824 HLA-nonrisk children (p < 0.001). By age 9 years, celiac disease was diagnosed in 72/1910 (3.8%) HLA-risk children compared with 0/2167 HLA-nonrisk children (p < 0.001). Screening at age 15 years detected 14/1071 (1.3%) HLA-risk children positive for IgA-tTG and/or IgG-tTG of whom 12/1071 (1.1%) remained persistently positive. Among those, 10/1071 (0.9%, 95% confidence interval: 0.4%-1.7%) HLA-risk children were diagnosed with celiac disease compared with 0/1303 HLA-nonrisk children (p < 0.001) and 5/491 (1.0%) were negative in screenings at both 3 and 9 years of age.

CONCLUSIONS

Screening for celiac disease needs to be performed at multiple timepoints to detect all cases but can be restricted to children at HLA-risk.

[Celiac disease]

Celiac disease is a frequent auto-immune disease characterized by villous atrophy related to gluten intake in patients with genetic susceptiblity. Patients do not present symptoms in the majority of cases. Presence of the disease must be investigated in case of digestive symptoms or presence of auto-immune disease. Diagnosis is based on anti-transglutaminase antibody and dudodenal biospies. The only available treatment is gluten-free diet. Associated auto-immune diseases must be investigated, especially thyroiditis. Complications related to nutritional deficiency must be accounted for also.

Novel Therapies for Celiac Disease: A Clinical Review Article

Celiac disease is emerging as an autoimmune disorder with increasing prevalence and incidence. The mean age of presentation is also increasing with the passage of time. The delay in diagnosis is partly attributable to the asymptomatic state in which most patients present. The diagnosis of the disease is primarily based on biopsy, but serology can also be included for possible screening purposes. Although the primary management strategy is to eliminate gluten from the diet of such patients; however, compliance with the diet and follow-up to detect healing might be difficult to maintain. Therefore, there is a need to investigate further management therapies that can be easily administered and monitored. The aim of the review is to discuss the epidemiology, clinical presentation, and novel therapies being investigated for celiac disease.

HLA-DQ genotype distribution and risk evaluation of celiac disease in Northwest China

BACKGROUND

Celiac disease (CD) is an autoimmune small bowel disease. Genetic susceptibility for CD is mainly determined by the human leukocyte antigen (HLA)-DQ haplotypes. The risk of CD conferred by HLA genotypes varies geographically and across populations, however, this has not yet been documented in Chinese patients with CD.

AIMS

To investigate the distribution of HLA-DQ and the related risks of CD development in Northwest China.

METHODS

A total of 75 CD patients and 300 healthy individuals were genotyped for HLA-DQ using the Illumina NextSeq, and the relative risks of the different genotypes were evaluated.

RESULTS

In total, 68.00% of CD patients and 21.00% of controls carried HLA-DQ2.5 heterodimers (p < 0.001). We identified four CD risk gradients. Individuals carrying a double dose of DQB1*02 had the highest risk of developing CD (1:16); however, with heterozygosis (DQB1*02:02/DQB1*02:01) having the highest risk (1:9). HLA-DQ2.5 individuals with a single copy of HLA-DQB1*02, in either the cis or trans configuration, were at a medium risk (1:38). Non-DQ2.5 carriers of DQ8 or DQ2.2 were at low risk, while only carriers of DQ7.5 or DQX.5 were at very low risk. Patients with the HLA-DQ2.5 genotype had more severe mucosal damage compared with the HLA-DQ2.5 genotype negative CD patients (70.59% vs. 41.67%, p = 0.016).

CONCLUSION

Genetic susceptibility to CD is highly prevalent in the Northwest Chinese population and the highest risk of developing CD was associated with the DQ2.5/DQ2.2 genotype. The DQ2.5 allele is involved in the severity of mucosal injury.

Guidelines of the Italian societies of gastroenterology on the diagnosis and management of coeliac disease and dermatitis herpetiformis

INTRODUCTION

Coeliac disease and dermatitis herpetiformis are immune-mediated diseases triggered by the consumption of gluten in genetically predisposed individuals. These guidelines were developed to provide general practitioners, paediatricians, gastroenterologists, and other clinicians with an overview on the diagnosis, management and follow-up of coeliac patients and those with dermatitis herpetiformis.

METHODS

Guidelines were developed by the Italian Societies of Gastroenterology. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists and a paediatrician with expertise in this field.

RESULTS

These guidelines provide a practical guidance for the diagnosis, management and follow-up of coeliac patients and dermatitis herpetiformis in children and adults, both in primary care and in specialist settings. We developed four sections on diagnosis, gluten-free diet, follow-up and risk of complications in adults, one section focused on diagnosis and follow-up in children and one on the diagnosis and management of dermatitis herpetiformis.

CONCLUSIONS

These guidelines may support clinicians to improve the diagnosis and management of patients with coeliac disease.

Defining the optimum strategy for identifying adults and children with coeliac disease: systematic review and economic modelling

BACKGROUND

Coeliac disease is an autoimmune disorder triggered by ingesting gluten. It affects approximately 1% of the UK population, but only one in three people is thought to have a diagnosis. Untreated coeliac disease may lead to malnutrition, anaemia, osteoporosis and lymphoma.

OBJECTIVES

The objectives were to define at-risk groups and determine the cost-effectiveness of active case-finding strategies in primary care.

DESIGN

(1) Systematic review of the accuracy of potential diagnostic indicators for coeliac disease. (2) Routine data analysis to develop prediction models for identification of people who may benefit from testing for coeliac disease. (3) Systematic review of the accuracy of diagnostic tests for coeliac disease. (4) Systematic review of the accuracy of genetic tests for coeliac disease (literature search conducted in April 2021). (5) Online survey to identify diagnostic thresholds for testing, starting treatment and referral for biopsy. (6) Economic modelling to identify the cost-effectiveness of different active case-finding strategies, informed by the findings from previous objectives.

DATA SOURCES

For the first systematic review, the following databases were searched from 1997 to April 2021: MEDLINE® (National Library of Medicine, Bethesda, MD, USA), Embase® (Elsevier, Amsterdam, the Netherlands), Cochrane Library, Web of Science™ (Clarivate™, Philadelphia, PA, USA), the World Health Organization International Clinical Trials Registry Platform ( WHO ICTRP ) and the National Institutes of Health Clinical Trials database. For the second systematic review, the following databases were searched from January 1990 to August 2020: MEDLINE, Embase, Cochrane Library, Web of Science, Kleijnen Systematic Reviews ( KSR ) Evidence, WHO ICTRP and the National Institutes of Health Clinical Trials database. For prediction model development, Clinical Practice Research Datalink GOLD, Clinical Practice Research Datalink Aurum and a subcohort of the Avon Longitudinal Study of Parents and Children were used; for estimates for the economic models, Clinical Practice Research Datalink Aurum was used.

REVIEW METHODS

For review 1, cohort and case-control studies reporting on a diagnostic indicator in a population with and a population without coeliac disease were eligible. For review 2, diagnostic cohort studies including patients presenting with coeliac disease symptoms who were tested with serological tests for coeliac disease and underwent a duodenal biopsy as reference standard were eligible. In both reviews, risk of bias was assessed using the quality assessment of diagnostic accuracy studies 2 tool. Bivariate random-effects meta-analyses were fitted, in which binomial likelihoods for the numbers of true positives and true negatives were assumed.

RESULTS

People with dermatitis herpetiformis, a family history of coeliac disease, migraine, anaemia, type 1 diabetes, osteoporosis or chronic liver disease are 1.5-2 times more likely than the general population to have coeliac disease; individual gastrointestinal symptoms were not useful for identifying coeliac disease. For children, women and men, prediction models included 24, 24 and 21 indicators of coeliac disease, respectively. The models showed good discrimination between patients with and patients without coeliac disease, but performed less well when externally validated. Serological tests were found to have good diagnostic accuracy for coeliac disease. Immunoglobulin A tissue transglutaminase had the highest sensitivity and endomysial antibody the highest specificity. There was little improvement when tests were used in combination. Survey respondents (n = 472) wanted to be 66% certain of the diagnosis from a blood test before starting a gluten-free diet if symptomatic, and 90% certain if asymptomatic. Cost-effectiveness analyses found that, among adults, and using serological testing alone, immunoglobulin A tissue transglutaminase was most cost-effective at a 1% pre-test probability (equivalent to population screening). Strategies using immunoglobulin A endomysial antibody plus human leucocyte antigen or human leucocyte antigen plus immunoglobulin A tissue transglutaminase with any pre-test probability had similar cost-effectiveness results, which were also similar to the cost-effectiveness results of immunoglobulin A tissue transglutaminase at a 1% pre-test probability. The most practical alternative for implementation within the NHS is likely to be a combination of human leucocyte antigen and immunoglobulin A tissue transglutaminase testing among those with a pre-test probability above 1.5%. Among children, the most cost-effective strategy was a 10% pre-test probability with human leucocyte antigen plus immunoglobulin A tissue transglutaminase, but there was uncertainty around the most cost-effective pre-test probability. There was substantial uncertainty in economic model results, which means that there would be great value in conducting further research.

LIMITATIONS

The interpretation of meta-analyses was limited by the substantial heterogeneity between the included studies, and most included studies were judged to be at high risk of bias. The main limitations of the prediction models were that we were restricted to diagnostic indicators that were recorded by general practitioners and that, because coeliac disease is underdiagnosed, it is also under-reported in health-care data. The cost-effectiveness model is a simplification of coeliac disease and modelled an average cohort rather than individuals. Evidence was weak on the probability of routine coeliac disease diagnosis, the accuracy of serological and genetic tests and the utility of a gluten-free diet.

CONCLUSIONS

Population screening with immunoglobulin A tissue transglutaminase (1% pre-test probability) and of immunoglobulin A endomysial antibody followed by human leucocyte antigen testing or human leucocyte antigen testing followed by immunoglobulin A tissue transglutaminase with any pre-test probability appear to have similar cost-effectiveness results. As decisions to implement population screening cannot be made based on our economic analysis alone, and given the practical challenges of identifying patients with higher pre-test probabilities, we recommend that human leucocyte antigen combined with immunoglobulin A tissue transglutaminase testing should be considered for adults with at least a 1.5% pre-test probability of coeliac disease, equivalent to having at least one predictor. A more targeted strategy of 10% pre-test probability is recommended for children (e.g. children with anaemia).

FUTURE WORK

Future work should consider whether or not population-based screening for coeliac disease could meet the UK National Screening Committee criteria and whether or not it necessitates a long-term randomised controlled trial of screening strategies. Large prospective cohort studies in which all participants receive accurate tests for coeliac disease are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019115506 and CRD42020170766.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 44. See the NIHR Journals Library website for further project information.

Systematic approach to celiac disease: a comprehensive review for primary providers

Celiac disease is an immune-mediated illness to gluten exposure in genetically susceptible patients. It is characterized by chronic lymphocytic inflammation of the small bowel leading to villous atrophy and its associated complications. The global prevalence of celiac disease is increasing, due in part to improved screening tests and simplified diagnostic criteria. Novel therapies are being developed and include proteolytic enzymes, sequestering agents, and immunotherapies. A strict gluten-free diet, however, remains the mainstay of treatment. In this comprehensive review, we discuss the epidemiology, definitions, diagnosis, and treatment of celiac disease.

The Association between ADHD and Celiac Disease in Children

Controversy around the association between celiac disease (CeD) and attention deficit hyperactive disorder (ADHD) was addressed by a systematic review in 2015, ultimately showing no association. Since 2015, there have been several studies showing an association between celiac disease and attention deficit hyperactive disorder. This is an updated systematic review.

BACKGROUND

Most experts agree on the recommendation to not screen as part of the standard of care for ADHD in persons with CeD or vice versa. Simultaneously, they propose that untreated patients with CeD and neurological symptoms such as chronic fatigue, inattention, pain, and headache could be predisposed to ADHD-like behavior, namely inattention (which may be alleviated by following a gluten-free diet). The inattentive subtype of ADHD that encompasses the symptoms of inattention is phenotypically heterogeneous, as it includes the clinical construct of sluggish cognitive tempo (SCT). SCT symptoms overlap with the neurological manifestations of CeD.

METHODS

A systematic search (PRISMA) of PubMed, Google Scholar, EMBASE, Web of Science, Stanford Lane, SCOPUS, and Ovid was conducted for articles up to 21 February 2022. Of these, 23 studies met the criteria.

RESULTS

Out of the 23 studies, 13 showed a positive association between ADHD and CeD. Most studies that showed a positive association had been published in the last five years. Inconsistencies in the results remain due to the heterogeneous methodology used, specifically for ADHD and the outcome questionnaires, as well as a lack of reporting on ADHD subtypes.

CONCLUSION

There is an association between ADHD and celiac disease. The current methodological limitations will be lessened if we examine the subtypes of ADHD.

The global burden of coeliac disease: opportunities and challenges

Coeliac disease is a systemic disorder characterized by immune-mediated enteropathy, which is caused by gluten ingestion in genetically susceptible individuals. The clinical presentation of coeliac disease is highly variable and ranges from malabsorption through solely extra-intestinal manifestations to asymptomatic. As a result, the majority of patients with coeliac disease remain undiagnosed, misdiagnosed or experience a substantial delay in diagnosis. Coeliac disease is diagnosed by a combination of serological findings of disease-related antibodies and histological evidence of villous abnormalities in duodenal biopsy samples. However, variability in histological grading and in the diagnostic performance of some commercially available serological tests remains unacceptably high and confirmatory assays are not readily available in many parts of the world. Currently, the only effective treatment for coeliac disease is a lifelong, strict, gluten-free diet. However, many barriers impede patients' adherence to this diet, including lack of widespread availability, high cost, cross-contamination and its overall restrictive nature. Routine follow-up is necessary to ensure adherence to a gluten-free diet but considerable variation is evident in follow-up protocols and the optimal disease management strategy is not clear. However, these challenges in the diagnosis and management of coeliac disease suggest opportunities for future research.

HLA DQ2/DQ8 haplotypes and anti-transglutaminase antibodies as celiac disease markers in a pediatric population with type 1 diabetes mellitus

Objective

Evaluate the celiac disease (CD) markers, within the scope of its screening, in a pediatric population with diagnosis of type 1 diabetes (T1D) at Hospital de Braga (HB) and determine the prevalence of CD in the sample. Reflect on CD screening algorithm applied in this pediatric population.

Methods

Retrospective observational study with 94 patients diagnosed with T1D at age 10 years or younger, followed up at the HB Outpatient Diabetology Consultation, including those referred from other hospitals. Record of clinical information, IgA anti-transglutaminase and anti-endomysium and HLA DQ2/DQ8 haplotypes.

Results

We obtained positive serological test for CD in 4 patients. This test had 100% sensitivity and specificity. The prevalence of CD was 4.3% (n = 4). Positive HLA screening in 84.6% of patients, with both sensitivity and negative predictive value of 100% and specificity of 16.67%. Diagnosis of CD was made on average 3.40 ± 3.32 years after the diagnosis of TD1. All cases of CD registered non-gastrointestinal manifestations, none had gastrointestinal symptoms.

Conclusion

This study proved that there is a higher prevalence of CD in pediatric population with TD1, when compared to general population, and clarified the importance of CD screening. Furthermore, it was observed that serological screening for CD antibodies is an excellent screening test and HLA typing, although not the most suitable first line test, can be useful in excluding the possibility of patients with T1D developing CD.

TagSNP approach for HLA risk allele genotyping of Saudi celiac disease patients: effectiveness and pitfalls

BACKGROUND

Celiac disease (CD) is a genetically complex autoimmune disease which is triggered by dietary gluten. Human leukocyte antigen (HLA) class II genes are known to act as high-risk markers for CD, where >95% of CD patients carry (HLA), DQ2 and/or DQ8 alleles. Therefore, the present study was conducted to investigate the distribution of HLA haplotypes among Saudi CD patients and healthy controls by using the tag single nucleotide polymorphisms (SNP).

METHODS

HLA-tag SNPs showing strong linkage value (r2>0.99) were used to predict the HLA DQ2 and DQ8 genotypes in 101 Saudi CD patients and in 103 healthy controls by using real-time polymerase chain reaction technique. Genotype calls were further validated by Sanger sequencing method.

RESULTS

A total of 63.7% of CD cases and of 60.2% of controls were predicted to carry HLA-DQ2 and DQ8 heterodimers, either in the homozygous or heterozygous states. The prevalence of DQ8 in our CD patients was predicted to be higher than the patients from other ethnic populations (35.6%). More than 32% of the CD patients were found to be non-carriers of HLA risk haplotypes as predicted by the tag SNPs.

CONCLUSION

The present study highlights that the Caucasian specific HLA-tag SNPs would be of limited value to accurately predict CD specific HLA haplotypes in Saudi population, when compared with the Caucasian groups. Prediction of risk haplotypes by tag SNPs in ethnic groups is a good alternate approach as long as the tag SNPs were identified from the local population genetic variant databases.

Best practices of handling, processing, and interpretation of small intestinal biopsies for the diagnosis and management of celiac disease: A joint consensus of Indian association of pathologists and microbiologists and Indian society of gastroenterology

The Indian Association of Pathologists and Microbiologists (IAPM) and Indian Society of Gastroenterology (ISG) decided to make a joint consensus recommendation for handling, processing, and interpretation of SI biopsies for the diagnosis and management of celiac disease (CD) recognizing the inhomogeneous practice of biopsy sampling, orientation, processing, and interpretation. A modified Delphi process was used to develop this consensus document containing a total of 42 statements and recommendations, which were generated by sharing the document draft, incorporating expert's opinion, followed by three cycles of electronic voting as well as a full-day face-to-face virtual ZOOM meeting and review of supporting literature. Of the 42 statements, 7 statements are on small intestinal (SI) biopsy in suspected patients of CD, site and the number of biopsies; 7 on handling, fixative, orientation, processing, and sectioning in pathology laboratories; 2 on histological orientation; 13 statements on histological interpretation and histological grading; 3 on the assessment of follow-up biopsies; 2 statements on gluten-free diet (GFD)-nonresponsive CD; 4 on challenges in the diagnosis of CD; 2 statements each on pathology reporting protocol and training and infrastructure in this area. The goal of this guideline document is to formulate a uniform protocol agreed upon both by the experienced pathologists and gastroenterologists to standardize the practice, improve the yield of small bowel biopsy interpretation, patients' compliance, overall management in CD, and generate unified data for patient care and research in the related field.

Estimating the Impact of Verification Bias on Celiac Disease Testing

GOAL

The goal of this study was to estimate the impact of verification bias on the diagnostic accuracy of immunoglobulin A tissue transglutaminase (IgA tTG) in detecting celiac disease as reported by an authoritative meta-analysis, the 2016 Comparative Effectiveness Review (CER).

BACKGROUND

Verification bias is introduced to diagnostic accuracy studies when screening test results impact the decision to verify disease status.

MATERIALS AND METHODS

We adjusted the sensitivity and specificity of IgA tTG reported by the 2016 CER with the proportion of IgA tTG positive and negative individuals who are referred for confirmatory small bowel biopsy. We performed a systematic review from January 1, 2007, to July 19, 2017, to determine these referral rates.

RESULTS

The systematic review identified 793 articles of which 9 met inclusion criteria (n=36,477). Overall, 3.6% [95% confidence interval (CI): 1.1%-10.9%] of IgA tTG negative and 79.2.2% (95% CI: 65.0%-88.7%) of IgA tTG positive individuals were referred for biopsy. Adjusting for these referral rates the 2016 CER reported sensitivity of IgA tTG dropped from 92.6% (95% CI: 90.2%-94.5%) to 57.1% (95% CI: 35.4%-76.4%) and the specificity increased from 97.6% (95% CI: 96.3%-98.5%) to 99.6% (95% CI: 98.4%-99.9%).

CONCLUSIONS

The CER may have largely overestimated the sensitivity of IgA tTG due to a failure to account for verification bias. These findings suggest caution in the interpretation of a negative IgA tTG to rule out celiac disease in clinical practice. More broadly, they highlight the impact of verification bias on diagnostic accuracy estimates and suggest that studies at risk for this bias be excluded from systematic reviews.

Immunosuppression-induced clonal T-cell lymphoproliferative disease causing severe diarrhoea mimicking coeliac disease following renal transplantation: a case report

Background

Post-transplant lymphoproliferative disease is a recognized complication following solid organ transplantation. This is usually a B cell disease and frequently associated with Epstein Barr virus infection, although T cell PTLD can occur. T cell PTLD is usually a monomorphic, lymphomatous disease associated with an adverse prognosis.

Case report

We report a 52 year old male pre-emptive renal transplant recipient who developed severe diarrhea with weight loss following intensification of his immunosuppression due to antibody mediated rejection 3 years after transplantation. Duodenal biopsy demonstrated monoclonal CD8+ T cell duodenitis leading to increased intraepithlieal lymphocytes and sub-total villous atrophy mimicking coeliac disease. Coeliac disease was excluded by negative anti-tissue transglutaminase antibody, HLA-DQ2 and HLA-DQ8 testing. There was no evidence of lymphoma either on biopsy or CT enterography and no FDG avid disease on PET. Symptoms did not improve with reduction of immunosuppression, but resolved fully on complete withdrawal of treatment. The transplant failed and he was established on dialysis. The diagnosis was early PTLD.

Conclusions

Oesophagogastroduodenoscopy with small bowel biopsies is a useful investigation for determining the cause of diarrhoea in renal transplant patients when more common causes have been excluded. This is the first report that we are aware of clonal T cell PTLD mimicking coeliac disease which only resolved after complete withdrawal of immunosuppression. As treatments for lymphoma are aggressive they are only initiated in the malignant phase and management of early stage PTLD is to minimise risk of progression by reducing immunosuppression. Any plans to retransplant will have to take into consideration the possibility that PTLD will recur.

A Clinician's Guide to Celiac Disease HLA Genetics

Celiac disease is a common inflammatory disease triggered by dietary gluten in genetically susceptible individuals. The strongest and best-characterized genetic susceptibilities in celiac disease are class II human leukocyte antigen (HLA) genes known as HLA-DQ2 and DQ8. HLA genetic testing is available through a number of commercial and academic laboratories and is used in the evaluation of celiac disease and to identify at-risk family members. Importantly, HLA genetic testing has a high negative predictive value for celiac disease, but a low positive predictive value. Therefore, for a practicing clinician, it is important to understand when to order HLA genetic testing, what test to order, and how to interpret the result. This review provides a practical primer on HLA genetics in celiac disease.

Novel Nondietary Therapies for Celiac Disease

Celiac Disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed individuals. CeD is one of the most common autoimmune disorders affecting around 1% of the population worldwide. Currently, the only acceptable treatment for CeD is strict, lifelong adherence to a gluten-free diet (GFD) which can often present a challenging task. A GFD alone is not sufficient to control symptoms and prevent mucosal damage that can result from unintentional gluten exposure. Moreover, long-term complications can occur in many patients. Consequently, there is an unmet need for non-dietary therapies for the management of CeD. Such therapies could serve as an adjunct to the GFD but eventually may replace it. This review will focus on and discuss non-dietary therapies currently in clinical development for the management of CeD. METHODOLOGY: We searched clinicaltrials.gov and PubMed to extract articles about celiac disease. We used keywords including, but not limited to, "celiac disease," "non-dietary," "therapeutics," "pathophysiology," "Endopeptidases," "tight junction modulators," "vaccine," and "Nexvax2". We focused mainly on articles that conducted pathophysiologic and therapeutic research in human trials.

Validation of a novel single-drop rapid human leukocyte antigen-DQ2/-DQ8 typing method to identify subjects susceptible to celiac disease

BACKGROUND AND AIM

Human leukocyte antigen (HLA)-DQ2 and/or -DQ8 is an essential risk factor for celiac disease (CD). About 90-95% of patients with CD carry HLA-DQ2/-DQ8 alleles, and HLA-DQ typing is considered an additional diagnostic test. Conventional polymerase chain reaction (PCR)-based HLA-DQ typing methods are expensive, complex, and a time-consuming process. We assessed the efficacy of a novel HLA-DQ typing method, "Celiac Gene Screen," for the detection of CD-associated HLA haplotypes.

METHODS

To assess the diagnostic performance of the Celiac Gene Screen test, 100 ethylenediaminetetraacetic acid (EDTA) blood samples, already characterized by the conventional HLA-DQ typing method, that is, PCR sequence-specific oligonucleotide probes (PCR-SSOP), a concordance between both the methods were explored. For validity, a further 300 EDTA blood samples with unknown HLA-DQ status were genotyped using the Celiac Gene Screen test, including 141 samples from CD, 56 first-degree relatives (FDRs) of CD and 103 samples from controls.

RESULTS

Of the 100 samples with known status of HLA-DQ alleles, 79 samples were HLA-DQ2 and/or -DQ8 positive, and 21 samples were HLA-DQ2 and/or -DQ8 negative by conventional PCR. These 100 samples were re-typed using the Celiac Gene screen kit; all 79 positives were typed positive, and 21 negatives were typed negative for HLA-DQ alleles. Among 300 samples with unknown HLA-DQ status, 118 of 141 (84%) patients with CD, 48 of 56 (86%) FDRs of CD, and 52 of 103 (50%) controls typed positive for HLA-DQ alleles.

CONCLUSIONS

The Celiac Gene Screen HLA-DQ typing method showed excellent concordance with the conventional HLA-DQ typing method and could be a cost-reducing and effective method for CD-associated HLA screening.

Celiac Disease: Against the Grain in Gastroenterology

The incidence of celiac disease has risen quickly and has a worldwide distribution in Europe, North and South America, Asia, the Middle East and Africa. This is attributed in part to increased availability in screening but also to the fast-rising gluten consumption and perhaps unknown environmental factors. In daily practice, this means that more subclinical cases and very young and elderly patients are diagnosed. The pathogenesis of celiac disease is a T-cell driven process initiated by gluten, leading to increased intestinal permeability and villous atrophy. The process requires HLA genotypes DQ2, DQ8 or both. Additional non-HLA alleles have been identified in genome-wide association studies. Serological testing, followed by duodenal biopsies, are still required to confirm the diagnosis. Advances are in the making for novel biomarkers to monitor disease and for pharmacological support of celiac disease. Medical costs and patient-perceived disease burden remain high in celiac disease, which point to the need for ongoing research in drug development to improve quality of daily life. Drugs undergoing phase I and phase II clinical trials include intraluminal therapies and vaccines to restore immune tolerance. These therapies aim to reduce symptoms and mucosal injuries as adjunct therapies to a gluten-free diet.

Clinical intervention using Bifidobacterium strains in celiac disease children reveals novel microbial modulators of TNF-α and short-chain fatty acids

BACKGROUND & AIMS

Celiac disease (CD) is an immune-mediated systemic disease, caused by ingestion of gluten in genetically predisposed individuals. Gut microbiota dysbiosis might play a significant role in pathogenesis of chronic enteropathies and its modulation can be used as an intervention strategy in CD as well. In this study, we aimed to identify correlations between fecal microbiota, serum tumor necrosis factor alpha (TNF-α) and fecal short-chain fatty acids (SCFAs) in healthy children and children with CD after administration of probiotic Bifidobacterium breve BR03 and B632.

METHODS

A double-blind placebo-controlled study enrolled 40 children with CD (CD) and 16 healthy children (HC). CD children were randomly allocated into two groups, of which 20 belonged to the placebo (PL) group and 20 to the Probiotic (PR) group. The PR group received a probiotic formulation containing a mixture of 2 strains, B. breve BR03 (DSM 16604) and B. breve B632 (DSM 24706) in 1:1 ratio for 3 months. Subsequently, for statistical analysis, blood and fecal samples from CD children (on enrolment - T0 and after 3 months, at the end of intervention with probiotic/placebo - T1) and HC children were used. The HC group was sampled only once (T0).

RESULTS

Verrucomicrobia, Parcubacteria and some yet unknown phyla of Bacteria and Archaea may be involved in the disease, indicated by a strong correlation to TNF-α. Likewise, Proteobacteria strongly correlated with fecal SCFAs concentration. The effect of probiotic administration has disclosed a negative correlation between Verrucomicrobia, some unknown phyla of Bacteria, Synergistetes, Euryarchaeota and some SCFAs, turning them into an important target in microbiome restoration process. Synergistetes and Euryarchaeota may have a role in the anti-inflammatory process in healthy human gut.

CONCLUSIONS

Our results highlight new phyla, which may have an important relation to disease-related parameters, CD itself and health.

Measuring Change In Small Intestinal Histology In Patients With Celiac Disease

Small intestinal histologic abnormalities in celiac disease include atrophy of the intestinal villi, hypertrophy of the crypts and lymphocytic infiltration of intraepithelial spaces and lamina propria. These findings are central to diagnosis and their severity and change over time are valuable to monitor disease course and response to therapy. Subjective methods to grade celiac disease histological severity include the Marsh-Oberhuber and Corazza-Villanacci systems. Quantitative histology uses villus height (Vh), crypt depth (Cd), and intra-epithelial lymphocyte count (per 100 enterocytes) to provide objective measures of histologic changes including Vh:Cd ratio. Here we examine the available literature regarding these methodologies and support the use of quantitative histology as the preferred method for accurately and reproducibly demonstrating change of relevant histologic end points over time. We also propose a Quantitative-Mucosal Algorithmic Rules for Scoring Histology (Q-MARSH) system to partially align quantitative histology results with the traditional Marsh, Marsh-Oberhuber, and Corazza-Villanacci systems. Q-MARSH can provide a standardized, objective, and quantitative histology scoring system for use as a clinical or research application.

Coeliac disease

Coeliac disease occurs in about 1% of people in most populations. Diagnosis rates are increasing, and this seems to be due to a true rise in incidence rather than increased awareness and detection. Coeliac disease develops in genetically susceptible individuals who, in response to unknown environmental factors, develop an immune response that is subsequently triggered by the ingestion of gluten. The disease has many clinical manifestations, ranging from severe malabsorption to minimally symptomatic or non-symptomatic presentations. Diagnosis requires the presence of duodenal villous atrophy, and most patients have circulating antibodies against tissue transglutaminase; in children, European guidelines allow a diagnosis without a duodenal biopsy provided that strict symptomatic and serological criteria are met. Although a gluten-free diet is an effective treatment in most individuals, a substantial minority develop persistent or recurrent symptoms. Difficulties adhering to a gluten-free diet have led to the development of non-dietary therapies, several of which are undergoing trials in human beings.

The incidence of HLA-DQ2/DQ8 in Turkish children with celiac disease and a comparison of the geographical distribution of HLA-DQ

Introduction

Celiac disease (CD) is an auto-immune enteropathy that occurs in genetically pre-disposed people as a result of the consumption of gluten-containing foods.

Aim

To identify the incidence of HLA-DQ2 and HLA-DQ8 observed in children with CD.

Material and methods

In this study, we focused on children ranging in age from 2 to 18 years and diagnosed with celiac disease. In our patients diagnosed with CD, in addition to tissue transglutaminase antibodies (anti-tTG), we also evaluated HLA-DQ2 B1 and HLA-DQ8 B1 alleles using the method of polymerase chain reaction (PCR)/sequence-specific oligonucleotide probes (Luminex^®). The detection of 0201/0202 for HLA-DQ2 allele and 0302 for HLA-DQ8 allele was accepted as a positive result.

Results

The mean age of our patients with celiac disease was 7.42 ±3.18 years, and the female/male ratio was 1.5/1. Seventy-six percent of our patients were HLA-DQ2 and/or HLA-DQ8 positive, 67% were HLA-DQ2 positive, and 25% were HLA-DQ8 positive. Nevertheless, 24% of them were HLA-DQ2 and HLA-DQ8 negative. The incidence of HLA-DQ2 in the control group was 18.8% with a significant difference compared to the HLA-DQ2 incidence in the patient group (67%) (p < 0.05). Similarly the HLA-DQ8 incidence in the control group (5.7%) was significantly lower than the incidence in the patient group (25%) (p < 0.05).

Conclusions

The incidence of the patients diagnosed with CD, who are HLA-DQ2 and HLA-DQ8 negative, varies among different populations.

Increasing Incidence and Altered Presentation in a Population-based Study of Pediatric Celiac Disease in North America

OBJECTIVES

Celiac disease (CD) is a common immune-mediated disorder that affects up to 1% of the general population. Recent reports suggest that the incidence of CD has reached a plateau in many countries. We aim to study the incidence and altered presentation of childhood CD in a well-defined population.

METHODS

Using the Rochester Epidemiology Project, we retrospectively reviewed Mayo Clinic and Olmsted Medical Center medical records from January 1994 to December 2014. We identified all CD cases of patients ages 18 years or younger at the time of diagnosis. Incidence rates were calculated by adjusting for age, sex, and calendar year and standardizing to the 2010 US white population.

RESULTS

We identified 100 patients with CD. Incidence of CD has increased from 8.1 per 100,000 person-years (2000-2002) to 21.5 per 100,000 person-years (2011-2014). There was an increase in CD prevalence in children from 2010 (0.10%) to 2014 (0.17%). Thirty-four patients (34%) presented with classical CD symptoms, 43 (43%) had nonclassical CD, and 23 (23%) were diagnosed by screening asymptomatic high-risk patients. Thirty-six patients (36%) had complete villous atrophy, 51 (51%) had partial atrophy, and 11 (11%) had increased intraepithelial lymphocytes. Two patients were diagnosed without biopsy. Most patients (67%) had a normal body mass index, 17% were overweight/obese, and only 9% were underweight.

CONCLUSIONS

Both incidence and prevalence of CD have continued to increase in children during the past 15 years in Olmsted County, Minnesota. Clinical and pathologic presentations of CD are changing over time (more nonclassical and asymptomatic cases are emerging).

Optimizing the diagnosis of celiac disease

PURPOSE OF REVIEW

The diagnostic approach in celiac disease is continuously evolving as our understanding of its pathophysiology improves. This review aims to provide a summary of contemporary work that supports optimization of the diagnosis of this common yet underdiagnosed condition.

RECENT FINDINGS

The recently updated National Institute of Clinical Excellence and European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines and the contentious biopsy-free diagnostic approach will be discussed. We will review the evidence advocating optimal biopsy techniques such as single bite biopsy and controversial bulb biopsy sampling to increase diagnostic yield. Recent data providing phenotypical characterization and clinical outcomes of celiac subtypes such as potential celiac disease, seronegative celiac disease and ultrashort celiac disease will be covered. We will present emerging evidence on novel case finding strategies with point of care tests. Promising novel markers for celiac disease such as serum intestinal fatty acid binding protein and in-vitro gluten challenge will be included.

SUMMARY

Recent work has demonstrated the clinical significance of the celiac disease subtypes, emphasizing the importance of careful diagnosis and recognition. There is a move toward a less invasive and perhaps more cost-effective diagnostic approach in celiac disease, but duodenal biopsy remains the gold standard at present for all adults and the majority of pediatric patients.

Current Status of Celiac Disease Drug Development

Celiac disease (CeD) is one of the most common immune-mediated diseases. Symptoms and disease activity are incompletely controlled by the gluten-free diet, which is currently the only available therapy. Although no therapies are yet approved, there is a growing field of candidates and an improving understanding of the regulatory pathway. In this review, we briefly discuss the epidemiology, pathophysiology, and current treatment paradigm for CeD. We also review the major classes of therapies being considered for CeD and discuss extensively what is known and can be surmised regarding the regulatory pathway for approval of a CeD therapeutic. The coming years will see an increasing number and diversity of potential therapies entering clinical trials and hopefully the first approved agents targeting this significant unmet medical need. Although biomarkers including histology and serology will always be important in therapeutic clinical trials, they currently lack the necessary evidence linking them to improved patient outcomes required for use as primary outcomes for drug approval. For this reason, patient-reported outcomes will likely be primary end points in Phase III CeD trials for the foreseeable future.

Administration of Bifidobacterium breve Decreases the Production of TNF-α in Children with Celiac Disease

BACKGROUND

Increasing evidence suggests that not only genetics, but also environmental factors like gut microbiota dysbiosis play an important role in the pathogenesis of celiac disease (CD).

AIM

The aim of our study was to investigate the effect of two probiotic strains Bifidobacterium breve BR03 and B. breve B632 on serum production of anti-inflammatory cytokine interleukin 10 (IL-10) and pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) in children with CD.

METHODS

The study was a double-blinded, placebo-controlled trial that included 49 children with CD on gluten-free diet (GFD) randomized into two groups and 18 healthy children in the control group. The first group (24 children with CD) daily received B. breve BR03 and B632 (2 × 10(9) colony-forming units) and the second group (25 children with CD) received placebo for 3 months.

RESULTS

TNF-α levels were significantly decreased in the first group after receiving B. breve for 3 months. On follow-up, 3 months after receiving probiotics, TNF-α levels increased again. Children with CD who were on GFD for less than 1 year showed similar baseline TNF-α levels as children who were on GFD for more than 1 year. IL-10 levels were in all groups of patients below detection level.

CONCLUSIONS

Probiotic intervention with B. breve strains has shown a positive effect on decreasing the production of pro-inflammatory cytokine TNF-α in children with CD on GFD.

Combination Testing Using a Single MSH5 Variant alongside HLA Haplotypes Improves the Sensitivity of Predicting Coeliac Disease Risk in the Polish Population

Assessment of non-HLA variants alongside standard HLA testing was previously shown to improve the identification of potential coeliac disease (CD) patients. We intended to identify new genetic variants associated with CD in the Polish population that would improve CD risk prediction when used alongside HLA haplotype analysis. DNA samples of 336 CD and 264 unrelated healthy controls were used to create DNA pools for a genome wide association study (GWAS). GWAS findings were validated with individual HLA tag single nucleotide polymorphism (SNP) typing of 473 patients and 714 healthy controls. Association analysis using four HLA-tagging SNPs showed that, as was found in other populations, positive predicting genotypes (HLA-DQ2.5/DQ2.5, HLA-DQ2.5/DQ2.2, and HLA-DQ2.5/DQ8) were found at higher frequencies in CD patients than in healthy control individuals in the Polish population. Both CD-associated SNPs discovered by GWAS were found in the CD susceptibility region, confirming the previously-determined association of the major histocompatibility (MHC) region with CD pathogenesis. The two most significant SNPs from the GWAS were rs9272346 (HLA-dependent; localized within 1 Kb of DQA1) and rs3130484 (HLA-independent; mapped to MSH5). Specificity of CD prediction using the four HLA-tagging SNPs achieved 92.9%, but sensitivity was only 45.5%. However, when a testing combination of the HLA-tagging SNPs and the MSH5 SNP was used, specificity decreased to 80%, and sensitivity increased to 74%. This study confirmed that improvement of CD risk prediction sensitivity could be achieved by including non-HLA SNPs alongside HLA SNPs in genetic testing.

Celiac Disease: Diagnostic Standards and Dilemmas

Celiac Disease (CD) affects at least 1% of the population and evidence suggests that prevalence is increasing. The diagnosis of CD depends on providers being alert to both typical and atypical presentations and those situations in which patients are at high risk for the disease. Because of variable presentation, physicians need to have a low threshold for celiac testing. Robust knowledge of the pathogenesis of this autoimmune disease has served as a catalyst for the development of novel diagnostic tools. Highly sensitive and specific serological assays including Endomysial Antibody (EMA), tissue transglutaminase (tTG), and Deamidated Gliadin Peptide (DGP) have greatly simplified testing for CD and serve as the foundation for celiac diagnosis. In addition, genetic testing for HLA DQ2 and DQ8 has become more widely available and there has been refinement of the gluten challenge for use in diagnostic algorithms. While diagnosis is usually straightforward, in special conditions including IgA deficiency, very young children, discrepant histology and serology, and adoption of a gluten free diet prior to testing, CD can be difficult to diagnose. In this review, we provide an overview of the history and current state of celiac disease diagnosis and provide guidance for evaluation of CD in difficult diagnostic circumstances.

The present and the future in the diagnosis and management of celiac disease

Celiac disease is an autoimmune enteropathy caused by gluten in genetically predisposed individuals. In celiac disease, adaptive and innate immune activation results in intestinal damage and a wide range of clinical manifestations. In the past, celiac disease was thought to result in signs and symptoms solely related to the gastrointestinal tract. Now, more than half of the adult population presents with extra-intestinal manifestations that can also be expected to improve on a gluten-free diet. For this reason, it is recommended that physicians have a low threshold of suspicion for celiac disease. Current knowledge of the immune pathogenesis of this autoimmune disease has served as a catalyst for the development of novel diagnostic tools and therapeutics. Over the years, highly sensitive and specific serological assays, in addition to genetic markers, have been found to target specific steps in the cascade pathway of celiac disease. Also the advent of the gluten challenge has enabled experts to design diagnostic algorithms and monitor clinical responses in clinical trials. The gluten challenge has provided substantial benefit in the advance of novel therapeutics as an adjuvant treatment to the gluten free diet. Generally, a strict gluten-free diet is highly burdensome to patients and can be limited in its efficacy. Alternative therapies-including gluten modification, modulation of intestinal permeability and immune response-could be central to the future treatment of celiac disease.