A novel serogenetic approach determines the community prevalence of celiac disease and informs improved diagnostic pathways

Patient and Community Health Global Burden in a World With More Celiac Disease

Celiac disease is one of the most common life-long disorders worldwide, with a prevalence mostly ranging between 0.7% and 2.9% in the general population and a higher frequency in females and well-defined at-risk groups, such as relatives of affected individuals and patients with autoimmune comorbidities. Increasing clinical detection is facilitated by improving awareness, implementation of a case-finding approach, and serology availability for screening at-risk patients, among other factors. Nevertheless, due to huge clinical variability, many celiac disease cases still escape diagnosis in most countries, unless actively searched by proactive policies. The burden of celiac disease is increasing, as is the need for better longitudinal care. Pediatric screening of the general population could represent the road ahead for an efficient intervention of secondary prevention aimed to reduce the social and health burden of celiac disease. This review analyses the epidemiology of celiac disease continent by continent, discusses current strategies to improve the detection of celiac disease, and highlights challenges related to the burden of celiac disease globally.

Relationship between gluten availability and celiac disease prevalence: A geo-epidemiologic systematic review

Celiac disease is a global disease requiring genetic susceptibility and gluten exposure to trigger immune-mediated enteropathy. The effect of the degree of gluten-containing grain availability on celiac disease prevalence is unknown. Our objective was to compare country-based gluten availability to celiac prevalence using a systematic literature review. We searched MEDLINE, Embase, Cochrane, and Scopus until May 2021. We included population-based serum screening with confirmatory testing (second serological study or small intestine biopsy) and excluded specific, high-risk, or referral populations. We determined country-specific gluten availability using the United Nations food balance for wheat, barley, and rye. Human leukocyte antigen (HLA) frequencies were obtained from allelefrequencies.net. The primary outcome was association between gluten-containing grain availability and celiac disease prevalence. Generalized linear mixed models method with Poisson's link was used for analysis. We identified 5641 articles and included 120 studies on 427 146 subjects from 41 countries. Celiac disease prevalence was 0-3.1%, median 0.75% (interquartile range 0.35, 1.22). Median wheat supply was 246 g/capita/day (interquartile range 214.8, 360.7). The risk ratio (RR) for wheat availability on celiac disease was 1.002 (95% confidence interval [CI]: 1.0001, 1.004, P = 0.036). A protective association was seen with barley, RR 0.973 (95% CI: 0.956, 0.99, P = 0.003), and rye, RR 0.989 (95% CI: 0.982, 0.997, P = 0.006). The RR for gross domestic product on celiac disease prevalence was 1.009 (95% CI: 1.005, 1.014, P < 0.001). The RR for HLA-DQ2 was 0.982 (95% CI: 0.979, 0.986, P < 0.001), and that for HLA-DQ8 was 0.957 (95% CI: 0.950, 0.964, P < 0.001). In this geo-epidemiologic study, gluten-containing grain availability showed mixed associations with celiac disease prevalence.

Meta-Analysis and Systematic Review of HLA DQ2/DQ8 in Adults with Celiac Disease

Although people with human leukocyte antigens (HLA) DQ2 and/or DQ8 are more likely to develop celiac disease (CD), the condition cannot be fully explained by this genetic predisposition alone. Multiple, as yet unidentified, factors contribute to the genesis of CD, including genetics, the environment, and the immune system. In order to provide insight into a prospective possibility and an expanded screening technique, we aim to undertake a comprehensive and meta-analytical study of the assessment and distribution of HLA class II (HLA-DQ2/DQ8) in adult CD patients. A systematic review was conducted using an electronic search of databases (PubMed, Google Scholar, Embase, and Direct Science) from January 2004 to February 2022. DQ2/DQ2 homozygotes have the highest risk of developing CD. DQ2/DQ8 typing is an effective test to exclude CD from the differential diagnosis of a patient with CD symptoms. Although other non-HLA genes have been associated with CD, they are rarely considered at diagnosis because they account for only a small proportion of the heritability of CD. This finding, together with the information gathered previously, may be useful in considering widely available and economically feasible screening options for celiac disease in young people.

Australasian paediatric gastroenterologist practices of coeliac disease diagnosis before and during the COVID-19 pandemic

AIM

To explore the perceptions and practices of Australasian paediatric gastroenterologists in diagnosing coeliac disease (CD) before and during the COVID-19 pandemic.

METHODS

Paediatric gastroenterologists in Australasia were invited via email to complete an anonymous online questionnaire over a 2-week period in 2021.

RESULTS

The questionnaire was completed by 39 respondents: 33 from Australia and six from New Zealand (NZ) equating to a 66% response rate. Thirty-four (87%) of the 39 respondents reported they currently practised non-biopsy diagnosis of CD in eligible children, while the rest diagnosed CD using biopsy confirmation only. All NZ respondents practised non-biopsy CD diagnosis. A majority of responders (76%) who practised non-biopsy CD diagnosis followed the 2020 European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines. Twenty-two (56%) respondents reported that they started using a non-biopsy CD diagnosis protocol before the pandemic and did not change their practice during the pandemic, 10 (26%) started diagnosing non-biopsy CD during the pandemic, 5 (13%) stated their practices of CD were not impacted by the pandemic and 2 (5%) did not respond on whether the pandemic changed their practice.

CONCLUSION

The majority of Australasian gastroenterologist respondents reported they routinely utilised the 2020 ESPGHAN diagnostic criteria in eligible children; half of them started prior to the pandemic and another quarter started this approach due to the pandemic. A minority of practitioners routinely rely only on biopsy confirmation to diagnose CD.

Review article: Diagnosis of coeliac disease: a perspective on current and future approaches

Diagnostics will play a central role in addressing the ongoing dramatic rise in global prevalence of coeliac disease, and in deploying new non-dietary therapeutics. Clearer understanding of the immunopathogenesis of coeliac disease and the utility of serology has led to partial acceptance of non-biopsy diagnosis in selected cases. Non-biopsy diagnosis may expand further because research methods for measuring gluten-specific CD4+ T cells and the acute recall response to gluten ingestion in patients is now relatively straightforward. This perspective on diagnosis in the context of the immunopathogenesis of coeliac disease sets out to highlight current consensus, limitations of current practices, gluten food challenge for diagnosis and the potential for diagnostics that measure the underlying cause for coeliac disease, gluten-specific immunity.

Evidence-Based and Emerging Diet Recommendations for Small Bowel Disorders

Diet plays a key role in the manifestation and severity of gastrointestinal symptoms, with increasing research interest on the role of diet in small bowel disorders. There are predominantly 3 small bowel conditions that have potential dietary interventions. Self-reported nonceliac gluten/wheat sensitivity is prevalent. Although gluten is believed to be a potential trigger for symptoms, other components of wheat may also be triggers, including fructans, alpha-amylase trypsin inhibitors, and wheat germ agglutinins. The diagnosis can be challenging, given the lack of validated biomarkers. A gluten-free diet that excludes the abovementioned triggers is the cornerstone of treatment; however, unlike celiac disease, there is uncertainty about the level of adherence or whether the gluten-free diet is a lifelong intervention. Several primary gastrointestinal disorders are associated with an increase in inflammatory cells including eosinophils. Diet seems to be an important driver of disease pathogenesis in eosinophilic gastroenteritis, with elimination and elemental diets showing promise in management, with further robust trials required. Small intestinal bacterial overgrowth is an example of microbial dysbiosis, with renewed interest in diet being postulated to cause an adaptive change of the microbes colonizing the small intestine. However, the diagnosis of small intestinal bacterial overgrowth is limited by a lack of sensitive and specific tests, with significant knowledge gaps in relation to therapeutic measures to manage and cure small intestinal bacterial overgrowth. Currently, antimicrobials are the established management option. There have been significant clinical advances in dietary interventions related to the small bowel, but this area is currently a novel and advancing field for both patients and clinicians.

Emerging Biomarkers for Screening and Management of Celiac Disease

Celiac disease (CeD) is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals expressing HLA-DQ2 and/or HLA-DQ8. In the current clinical practice, there are many serologic studies to aid in the diagnosis of CeD which include autoantibodies like IgA antitissue transglutaminase, antiendomysium, and antideamidated forms of gliadin peptide antibodies. Small intestinal biopsy has long been considered an essential step for the diagnosis of CeD. However, in the recent era, researchers have explored the possibility of CeD screening and diagnosis without endoscopy or biopsy. The newer emerging biomarkers of CeD appear promising in diagnostic evaluation and subsequent monitoring of disease. In this review of literature, we have explored the emerging biomarker-based diagnostic evaluation and monitoring of CeD.

Australasian Pediatric Gastroenterologists' Perspectives and Practices of Celiac Disease Diagnosis and Management

BACKGROUND

The application of the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) celiac disease (CeD) guidelines by pediatric gastroenterologists in Australia and New Zealand (Australasia) is unknown. Similarly, long-term management practices for patients with CeD are also unknown in this region.

AIMS

This study aimed to explore the perceptions and practices of Australasian pediatric gastroenterologists in diagnosing and managing patients with CeD.

METHODS

Australasian pediatric gastroenterologists and trainees were invited to complete an anonymous online survey over a 3-week period.

RESULTS

The survey was completed by 28 respondents, 24 from Australia and four from New Zealand. Tissue transglutaminase antibody IgA was the most frequently ordered initial serologic test. Fifteen (54%) respondents relied on duodenal biopsies for the confirmation of CeD, six (21%) followed the ESPGHAN guidelines and the remaining seven offered either biopsy confirmation or no-biopsy diagnosis according to the parents' wishes. Following diagnosis, five (18%) respondents discharged patients from care, three (11%) discharged patients after one follow-up visit, one (4%) reviewed patients for 12 months, six (21%) reviewed patients until celiac antibodies normalized and children were clinically asymptomatic, and 13 (46%) reviewed patients until transition to adult care.

CONCLUSION

Tissue transglutaminase antibody IgA was the most common initial serologic test ordered by this group of Australasian pediatric gastroenterologists. Half of these physicians rely solely on duodenal biopsy for the confirmation of CeD diagnosis: a minority routinely use the ESPGHAN guidelines. Physicians reported a wide range of CeD follow-up practices.

Undigestible Gliadin Peptide Nanoparticles Penetrate Mucus and Reduce Mucus Production Driven by Intestinal Epithelial Cell Damage

Wheat protein is the most consumed plant protein in our diet, and there is an increased prevalence of wheat/gluten intolerance and adherence to a gluten-free diet in many countries. Despite the known immunodominant effect of undigested gliadin peptides responsible for gluten-related intolerance, it remains unclear if and how gliadin peptides self-assemble into ordered nanostructures during gastrointestinal digestion, as well as their biological impact on the mucus barrier function. In this study, we purified undigestible gliadin peptide nanoparticles (UGPNs) by ultracentrifugation and characterized their structural and physiochemical properties. The results demonstrate that the UGPNs are self-assembled nanostructures generated by cationic amino acids (Lys and Arg)-capped surfactant-like peptides (SLPs), mainly derived from γ-gliadin and α-gliadin. SLPs trigger the concentration-dependent self-assembly driven by β-sheet conformational transitions above their critical aggregation concentration (cac, ∼0.1 mg/mL). UGPNs can easily penetrate the mucus layer in Caco-2/HT29-MTX cocultures with a high P_app value (∼5.7 × 10^-6 cm/s) and reduce the production and thickness of the mucus layer driven by intestinal epithelial cell damage. Isothermal titration calorimetry and Langmuir monolayer studies indicate that the self-assembled state of UGPNs significantly affects their binding to DPPC/DOPE lipid membrane models. These results highlight the relevance of the self-assembly of gliadin peptides as a trigger of mucosal inflammation-related wheat/gluten intolerance.

Wheat consumption and prevalence of celiac disease: Correlation from a multilevel analysis

Celiac disease (CD) is triggered by both genetic and environmental factors. More than 1% of the world's population is affected by CD. In recent years, studies have confirmed a worldwide rising trend in CD prevalence. "Westernized diet" is one of the main factors of this increasing prevalence. However, the relationship between wheat consumption, its dynamics, and CD has not been adequately investigated on a global scale. This study aimed to perform a multilevel analysis of the association between wheat consumption and CD. Wheat consumption data from countries and continents were obtained from the database. The relative increase/decrease in wheat consumption over a long period (since 1961) and a short period (since 2004) were calculated using various statistical tools. The relationship between wheat consumption and celiac frequency was determined using the R-commander R package version 2.6-2. Pearson's correlation coefficient (r = 0.88) confirmed a high positive correlation between wheat consumption and the prevalence of biopsy-proven CD by estimating continent-wide wheat consumption data, but an insignificant correlation was found when the data were compared country-wide.

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.

Prevalence of HLA DQ 2, 8 in children with celiac disease

OBJECTIVE

Celiac disease is a chronic disease that affect small bowel by making its villi become atrophic. Various environmental and genetic factors have been identify as inducing factors for celiac disease. Most of the patients has one of the HLA DQ forms. Although the prevalence of these genes are variable in different areas of the world, we do not have a comprehensive information about this issue in our region. Thus the aim of present study is to investigate the prevalence of HLA DQ typing of patients who visited Emam Reza Gastroenterology clinic of Shiraz(IRAN).

METHODS

In this case-control study all under 18 years old children who were diagnosed with celiac disease and have visited Emam Reza gastroenterology clinic were investigated. The diagnosis of celiac disease was made by history, physical exam, serologic test, and histopathology of duodenal biopsy. Blood sample was taken and HLA typing performed using PCR method at Motahari clinic cytology laboratory. Also those people who neither them self nor their first degree relatives were not case of celiac disease and underwent HLA typing for other reason were identified as control group. The statistical analysis was done using SPSS 18 software. The p value < 0.05 was identified as statistically significant.

RESULTS

A total of 139 patients with celiac disease and 146 normal children were studied. The mean age of the patient with celiac disease were 9.1 years old with standard deviation of 3.4 years old. 64% of the celiac patients were girls and 36% were boys. While this proportion was 54.4% for boy and 48.6% for girls in control group. The most common HLA in celiac patients group were HLA DQ2 and 8 but the most common ones in control group were HLA DQ 8 and 5. Failure to Thrive were the most common signs of the celiac patients with a prevalence of 60 children. Total IgA titer were normal in 98.6% of the patients and TTG IgA titer were positive in 93.5% of the patients. The most common co existing disease with the celiac disease were diabetes with a prevalence of 30 children (66.7%).

CONCLUSION

present study reveals that the prevalence of the HLA DQ2 and 8 among patients with celiac disease is 72.6% and 53% in our normal population.

Nutri-epigenetics: the effect of maternal diet and early nutrition on the pathogenesis of autoimmune diseases

Autoimmune diseases comprise a wide group of diseases involving a self-response of the immune system against the host. The etiopathogenesis is very complex involving disease-specific factors but also environmental factors, among which the diet. Maternal diet during pregnancy as well as early nutrition recently attracted the interest of the scientists as contributing to the immune programming. In this paper, we reviewed the most recent literature on the effect of maternal diet and early nutrition in modulating the immune system in a selected subset of autoimmune diseases: type 1 diabetes, celiac disease, inflammatory bowel disease, juvenile idiopathic arthritis and rheumatoid arthritis. Particularly, we focused our narrative on the role of maternal and perinatal nutrition in the epigenetic mechanisms underlying the auto-immune response. Maternal diet during pregnancy as well as breastfeeding and early nutrition play a big role in many epigenetic mechanisms. Most of the nutrients consumed by the mother and the infant are known exerting epigenetic functions, such as folate, methionine, zinc, vitamins B12 and D, fibers, casein and gliadin, and they were linked to gene expression changes in the immune pathways. Despite the common role of maternal diet, breastfeeding and early nutrition in almost all the autoimmune diseases, each disease seems to have specific diet-driver epigenetic mechanisms that require further investigations. The research in this field is opening new routes to establishing a precision nutrition approach to the auto-immune diseases.

Coeliac disease and noncoeliac wheat or gluten sensitivity

Coeliac disease (CD) and noncoeliac wheat or gluten sensitivity (NCWS/NCGS) are common gluten-related disorders. Both conditions can present with gastrointestinal and extraintestinal manifestations, which can be a challenge for physicians to discern between. Whilst coeliac serology and histological assessment are required for the diagnosis of CD, there are no clear biomarkers for the diagnosis of NCGS. The management of both conditions is with a gluten-free diet (GFD), although the duration, as well as strictness of adherence to a GFD in NCGS, is unclear. Adherence to a GFD in CD can also be challenging, with recent developments of noninvasive assessments, although histological assessment via duodenal biopsies remains the gold standard. The management of refractory coeliac disease remains particularly challenging, often requiring specialist input. Whilst wheat is noted to be a trigger for symptom generation in NCGS, it is unclear which components of wheat are responsible for symptom generation in this group, with further research required to elucidate the pathophysiology.

Distribution of HLA-DQ risk genotypes for celiac disease in Ethiopian children

Most patients with celiac disease are positive for either HLA‐DQA1*05:01‐DQB1*02 (DQ2.5) or DQA1*03:01‐DQB1*03:02 (DQ8). Remaining few patients are usually DQA1*02:01‐DQB1*02 (DQ2.2) carriers. Screenings of populations with high frequencies of these HLA‐DQA1‐DQB1 haplotypes report a 1% to 3% celiac disease prevalence. The aim was to determine the prevalence of HLA‐DQ risk haplotypes for celiac disease in Ethiopian children. Dried blood spots collected from 1193 children from the Oromia regional state of Ethiopia were genotyped for HLA‐DQA1 and DQB1 genotyping using an asymmetric polymerase chain reaction (PCR) and a subsequent hybridization of allele‐specific probes. As references, 2000 previously HLA‐genotyped children randomly selected from the general population in Sweden were included. DQ2.2 was the most common haplotype and found in 15.3% of Ethiopian children, which was higher compared with 6.7% of Swedish references (P < .0001). Opposed to this finding, DQ2.5 and DQ8 occurred in 9.7% and 6.8% of Ethiopian children, which were less frequent compared with 12.8% and 13.1% of Swedish references, respectively (P < .0001). The DQ2.5‐trans genotype encoded by DQA1*05‐DQB1*03:01 in combination with DQ2.2 occurred in 3.6% of Ethiopian children, which was higher compared with 1.3% of Swedish references (P < .0001). However, when children with moderate high to very high‐risk HLA genotypes were grouped together, there was no difference between Ethiopian children and Swedish references (27.4% vs 29.0%) (P = .3504). The frequency of HLA risk haplotypes for celiac disease is very similar in Ethiopian and Swedish children. This finding of importance will be useful in future screening of children for celiac disease in Ethiopia.

Improved HLA-based prediction of coeliac disease identifies two novel genetic interactions

Human Leucocyte Antigen (HLA) testing is useful in the clinical work-up of coeliac disease (CD) with high negative but low positive predictive value. We construct a genomic risk score (GRS) using HLA risk genotypes to improve CD prediction and guide exclusion criteria. Imputed HLA genotypes for five European CD case-control GWAS (n > 15,000) were used to construct and validate an interpretable HLA-based risk model (HDQ₁₅), which shows statistically significant improvements in predictive performance upon all previous HLA-based risk models. Conditioning on this model, we find two novel associations, HLA-DQ6.2 and HLA-DQ7.3, that interact significantly with HLA-DQ2.5 (p = 2.51 × 10^-9, 1.99 × 10^-7, respectively). Integrating these novel alleles into a new risk model (HDQ₁₇) leads to predictive performance equivalent or better than the strongest reported GRS (GRS₂₂₈) using 228 single nucleotide polymorphisms (SNPs). We also demonstrate that our proposed HLA-based models can be implemented using only six HLA tagging SNPs with statistically equivalent predictive performance. Using insights from our model to guide exclusionary criteria, we find the positive predictive value of CD testing in high-risk populations can be increased by 55%, from 17.5 to 27.1%, while maintaining a negative predictive value above 99%. Our results suggest that HLA typing is currently undervalued in CD assessment.

Comparison of DNA methylation profiles from saliva in Coeliac disease and non-coeliac disease individuals

BACKGROUND

Coeliac disease (CD) is a autoimmune disease characterised by mucosal inflammation in the small intestine in response to dietary gluten. Genetic factors play a key role with CD individuals carrying either the HLA-DQ2 or HLA-DQ8 haplotype, however these haplotypes are present in half the general population making them necessary but insufficient to cause CD. Epigenetic modifications, including DNA methylation that can change in response to environmental exposure could help to explain how interactions between genes and environmental factors combine to trigger disease development. Identifying changes in DNA methylation profiles in individuals with CD could help discover novel genomic regions involved in the onset and development of CD.

METHODS

The Illumina InfiniumMethylation450 Beadchip array (HM450) was used to compare DNA methylation profiles in saliva, in CD and non-CD affected individuals. CD individuals who had been diagnosed at least 2 years previously; were on a GFD; and who were currently asymptomatic; were compared to age and sex-matched non-CD affected healthy controls. Bisulphite pyrosequencing was used to validate regions found to be differentially methylated. These regions were also validated in a second larger cohort of CD and non-CD affected individuals.

RESULTS

Methylation differences within the HLA region at HLA-DQB1 were identified on HM450 but could not be confirmed with pyrosequencing. Significant methylation differences near the SLC17A3 gene were confirmed on pyrosequencing in the initial pilot cohort. Interestingly pyrosequencing sequencing of these same sites within a second cohort of CD and non-CD affected controls produced significant methylation differences in the opposite direction.

CONCLUSION

Altered DNA methylation profiles appear to be present in saliva in CD individuals. Further work to confirm whether these differences are truly associated with CD is needed.

Cytokine release after gluten ingestion differentiates coeliac disease from self-reported gluten sensitivity

BACKGROUND

Diagnosing coeliac disease (CD) in patients on a gluten-free diet (GFD) is difficult. Ingesting gluten elevates circulating interleukin (IL)-2, IL-8 and IL-10 in CD patients on a GFD.

OBJECTIVE

We tested whether cytokine release after gluten ingestion differentiates patients with CD from those with self-reported gluten sensitivity (SR-GS).

METHODS

Australian patients with CD (n = 26) and SR-GS (n = 18) on a GFD consumed bread (estimated gluten 6 g). Serum at baseline and at 3 and 4 h was tested for IL-2, IL-8 and IL-10. Separately, Norwegian SR-GS patients (n = 49) had plasma cytokine assessment at baseline and at 2, 4 and 6 h after food bars containing gluten (5.7 g), fructan or placebo in a previous double-blind crossover study.

RESULTS

Gluten significantly elevated serum IL-2, IL-8 and IL-10 at 3 and 4 h in patients with CD but not SR-GS. The highest median fold-change from baseline at 4 h was for IL-2 (8.06, IQR: 1.52-24.0; P < 0.0001, Wilcoxon test). The two SR-GS cohorts included only one (1.5%) confirmed IL-2 responder, and cytokine responses to fructan and placebo were no different to gluten. Overall, cytokine release after gluten was present in 22 (85%) CD participants, but 2 of the 4 non-responders remained clinically well after 1 y on an unrestricted diet. Hence, cytokine release occurred in 22 (92%) of 24 'verified' CD participants.

CONCLUSIONS

Gluten challenge with high-sensitivity cytokine assessment differentiates CD from SR-GS in patients on a GFD and identifies patients likely to tolerate gluten reintroduction. Systemic cytokine release indicating early immune activation by gluten in CD individuals cannot be detected in SR-GS individuals.

Non-Responsive Coeliac Disease: A Comprehensive Review from the NHS England National Centre for Refractory Coeliac Disease

Coeliac disease is a common small intestinal enteropathy which manifests following ingestion of gluten in genetically susceptible individuals. Since gluten was identified as the driving factor in coeliac disease, the gluten-free diet (GFD) has remained the mainstay of treatment. While most individuals will display improvement in symptoms and signs of coeliac disease following institution of the GFD, up to 30% will continue to experience symptoms and/or have persisting intestinal inflammation. These individuals can be classified as having non-responsive coeliac disease (NRCD), which may be associated with dietary indiscretion, slow healing, refractory coeliac disease, and/or an alternative condition. The purpose of this review is to provide an overview of the causes of NRCD in adults, highlight a systematic approach to investigate these patients, and appraise the latest management aspects of this subset of coeliac disease.

Incidence and prevalence of self-reported non-coeliac wheat sensitivity and gluten avoidance in Australia

OBJECTIVES

To determine the incidence of self-reported non-coeliac wheat sensitivity (SR-NCWS) and factors associated with its onset and resolution; to describe the prevalence of factors associated with gluten avoidance.

DESIGN

Longitudinal cohort study; analysis of responses to self-administered validated questionnaires (Digestive Health and Wellbeing surveys, 2015 and 2018).

SETTING, PARTICIPANTS

Subset of an adult population sample randomly selected in 2015 from the electoral rolls for the Newcastle and Gosford regions of New South Wales.

MAIN OUTCOME MEASURES

Prevalence of SR-NCWS (2015, 2018) and incidence and resolution of SR-NCWS, each by demographic and medical factors; prevalence of gluten avoidance and reasons for gluten avoidance (2018).

RESULTS

1322 of 2185 eligible participants completed the 2018 survey (response rate, 60.5%). The prevalence of SR-NCWS was similar in 2015 (13.8%; 95% CI, 12.0-15.8%) and 2018 (13.9%; 95% CI, 12.1-15.9%); 69 of 1301 respondents (5.3%) reported developing new onset (incident) SR-NCWS between 2015 and 2018 (incidence, 1.8% per year). Incident SR-NCWS was significantly associated with a diagnosis of functional dyspepsia, and negatively associated with being male or older. Gluten avoidance was reported in 2018 by 24.2% of respondents (20.5% partial, 3.8% complete avoidance); general health was the most frequent reason for avoidance (168 of 316 avoiders, 53%). All 13 participants with coeliac disease, 56 of 138 with irritable bowel syndrome (41%), and 69 of 237 with functional dyspepsia (29%) avoided dietary gluten.

CONCLUSIONS

The prevalence of SR-NCWS was similar in 2015 and 2018. Baseline (2015) and incident SR-NCWS (2018) were each associated with functional gastrointestinal disorders. The number of people avoiding dietary gluten exceeds that of people with coeliac disease or SR-NCWS, and general health considerations and abdominal symptoms are the most frequently reported reasons for avoidance.

Association between HLA alleles and risk of celiac disease in Iranian patients

Celiac disease (CD) is a common autoimmune disease that is manifested by inflammation of the small intestine and varying extra intestinal symptoms, also considered to be associated with human HLA-DQ genes. In this study, 40 patients of CD and 40 healthy control samples were genotyped for HLA-DQB1 and 14 patients of CD and 14 healthy control samples were genotyped for HLA-DQA1genes using the SSP-PCR technique and a commercial kit.The DQA1*05 allele had the highest frequency among the patient group (42.86%). The frequency of this allele was 28.57% in healthy controls, and there was no statistically significant difference in this case (p= 0.771).The DQB1*02 allele was the most common in patients (33.75%) followed by the DQB1*03 allele (31.25%).The difference in frequency of the HLA-DQB1*02 allele in the patient and control groups was statistically significant (P= 0.0002, OR = 4.72). The remarkable differences in the distribution of HLA-DQ2 in Iranian patients compared to controls and relative risks signified the role of these alleles in the development of CD in Iranian patients and confirmed the likelihood of using HLA-DQ typing in the substantiation of the disease.

European Society Paediatric Gastroenterology, Hepatology and Nutrition Guidelines for Diagnosing Coeliac Disease 2020

OBJECTIVES

The ESPGHAN 2012 coeliac disease (CD) diagnostic guidelines aimed to guide physicians in accurately diagnosing CD and permit omission of duodenal biopsies in selected cases. Here, an updated and expanded evidence-based guideline is presented.

METHODS

Literature databases and other sources of information were searched for studies that could inform on 10 formulated questions on symptoms, serology, HLA genetics, and histopathology. Eligible articles were assessed using QUADAS2. GRADE provided a basis for statements and recommendations.

RESULTS

Various symptoms are suggested for case finding, with limited contribution to diagnostic accuracy. If CD is suspected, measurement of total serum IgA and IgA-antibodies against transglutaminase 2 (TGA-IgA) is superior to other combinations. We recommend against deamidated gliadin peptide antibodies (DGP-IgG/IgA) for initial testing. Only if total IgA is low/undetectable, an IgG-based test is indicated. Patients with positive results should be referred to a paediatric gastroenterologist/specialist. If TGA-IgA is ≥10 times the upper limit of normal (10× ULN) and the family agrees, the no-biopsy diagnosis may be applied, provided endomysial antibodies (EMA-IgA) will test positive in a second blood sample. HLA DQ2-/DQ8 determination and symptoms are not obligatory criteria. In children with positive TGA-IgA <10× ULN at least 4 biopsies from the distal duodenum and at least 1 from the bulb should be taken. Discordant results between TGA-IgA and histopathology may require re-evaluation of biopsies. Patients with no/mild histological changes (Marsh 0/I) but confirmed autoimmunity (TGA-IgA/EMA-IgA+) should be followed closely.

CONCLUSIONS

CD diagnosis can be accurately established with or without duodenal biopsies if given recommendations are followed.

Bowel patterns, gastrointestinal symptoms, and emotional well-being in adolescents: A cohort study

BACKGROUND AND AIM

Bowel patterns are varied in the general population. Gastrointestinal symptoms are common reasons for clinical visits. We aimed to examine the usual bowel pattern and the prevalence and significance of gastrointestinal symptoms in a population-based cohort of Australian adolescents.

METHODS

Seventeen-year-old adolescents (n = 1279) in the Western Australian Pregnancy Cohort (Raine) Study participated in a cross-sectional assessment, involving health questionnaires. Questions included medical history, diet, bowel patterns, and gastrointestinal symptoms. Data were analyzed to identify patterns of bowel motions, gastrointestinal symptoms, and factors associated with these in adolescents. Multivariate logistic regression analysis was used to determine predictors of poorer self-rated health status.

RESULTS

The dominant pattern of bowel motions was passage of stool that was "not too hard and not too soft" (Bristol stool types 3 and 4) in 90% and occurring between three and seven times per week in 74%. The most prevalent gastrointestinal symptoms included abdominal bloating (72%), abdominal pain (36%), nausea (25%), and constipation (20%). A "Western" dietary pattern was associated with abdominal bloating, constipation, and nausea (P < 0.05). Apart from diarrhea, gastrointestinal symptoms were more prevalent in female adolescents than male adolescents (P < 0.05 for all). Female sex (odds ratio [OR] 1.87, 95% confidence interval [CI] 1.16-3.02, P = 0.01), nausea (OR 3.18, 95% CI 2.03-4.98, P < 0.001), and depression (OR 6.68, 95% CI 3.65-12.22, P = 0.03) were independently associated with poorer self-rated health status, after adjusting for other gastrointestinal symptoms.

CONCLUSIONS

In adolescents, bowel patterns and gastrointestinal symptoms are diverse and show sex differences. Nausea, depression, and female sex are significant factors for poorer self-rated health.

Narrow-band imaging with magnification and the water immersion technique: a case-finding, cost-effective approach to diagnose villous atrophy

INTRODUCTION

Narrow-band imaging with magnification endoscopy (NBI-ME) allows real-time visual assessment of the mucosal surface and vasculature of the gastrointestinal tract. This study aimed to determine the performance of NBI-ME combined with the water immersion technique (NBI-ME-WIT) in detecting villous atrophy.

METHODS

All patients who underwent gastroscopy were included. The duodenum was further examined with NBI-ME-WIT only after examination with white light endoscopy did not reveal a cause of anaemia or dyspepsia. Targeted biopsies were taken of visualised areas. NBI-ME-WIT findings were compared with the final histopathological analysis. We calculated the sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of NBI-ME-WIT in detecting villous atrophy and the hypothetical cost saved by using a biopsy-avoiding approach.

RESULTS

124 patients (83 female) with a mean age of 46 (range 18-82) years were included. The most common indication for gastroscopy was abdominal pain (39%), followed by anaemia (35%), chronic diarrhoea/altered bowel habits (19%) and dyspepsia (6%). NBI-ME-WIT was able to detect all nine patients with villous atrophy - eight patchy and one total villous atrophy. The Sn, Sp, PPV and NPV of NBI-ME-WIT in detecting villous atrophy were 100.0%, 99.1%, 90.0% and 100.0%, respectively. Taking into account the cost of biopsy forceps (AUD 17) and pathology (AUD 140), this biopsy-avoidance strategy could have saved AUD 18,055 in these patients.

CONCLUSION

NBI-ME-WIT is a specific and sensitive tool to recognise and accurately diagnose villous atrophy. Biopsies can be avoided in patients with normal-sized villi, which may decrease the overall cost of the procedure.

Assessing the Utility of Multiplexed Liquid Chromatography-Mass Spectrometry for Gluten Detection in Australian Breakfast Food Products

Coeliac disease (CD) is an autoimmune disorder triggered by the ingestion of gluten that is associated with gastrointestinal issues, including diarrhea, abdominal pain, and malabsorption. Gluten is a general name for a class of cereal storage proteins of wheat, barley, and rye that are notably resistant to gastrointestinal digestion. After ingestion, immunogenic peptides are subsequently recognized by T cells in the gastrointestinal tract. The only treatment for CD is a life-long gluten-free diet. As such, it is critical to detect gluten in diverse food types, including those where one would not expect to find gluten. The utility of liquid chromatography-mass spectrometry (LC-MS) using cereal-specific peptide markers to detect gluten in heavily processed food types was assessed. A range of breakfast products, including breakfast cereals, breakfast bars, milk-based breakfast drinks, powdered drinks, and a savory spread, were tested. No gluten was detected by LC-MS in the food products labeled gluten-free, yet enzyme-linked immunosorbent assay (ELISA) measurement revealed inconsistencies in barley-containing products. In products containing wheat, rye, barley, and oats as labeled ingredients, gluten proteins were readily detected using discovery proteomics. Panels comprising ten cereal-specific peptide markers were analyzed by targeted proteomics, providing evidence that LC-MS could detect and differentiate gluten in complex matrices, including baked goods and milk-based products.

Elevated serum interleukin-2 after gluten correlates with symptoms and is a potential diagnostic biomarker for coeliac disease

BACKGROUND

Coeliac disease patients on a gluten-free diet experience reactions to gluten, but these are not well characterised or understood. Systemic cytokine release was recently linked to reactivation of gluten immunity in coeliac disease.

AIM

To define the nature and time-course of symptoms and interleukin-2 changes specific for coeliac disease patients.

METHODS

25 coeliac disease patients on a gluten-free diet and 25 healthy volunteers consumed a standardised 6 gram gluten challenge. Coeliac Disease Patient-Reported Outcome survey and global digestive symptom assessment were completed hourly up to 6 hours after gluten. Adverse events over 48 hours were recorded. Serum interleukin-2 was measured at baseline, and 2, 4 and 6 hours.

RESULTS

Serum interleukin-2 was always undetectable in healthy controls, whereas it was undetectable at baseline and elevated >0.5 pg/ml at 4 hours in 92% of coeliac disease patients. All patient-reported outcome severity scores increased significantly after gluten in coeliac disease patients (P < .001 Wilcoxon signed rank test), but not in controls. Symptoms began after 1 hour, and peaked in the third. Nausea and vomiting characterised severe reactions, but mild reactions were limited to headache and tiredness. Peak interleukin-2 correlated with symptom severity, particularly for nausea and vomiting.

CONCLUSIONS

Serum interleukin-2 elevations correlate with timing and severity of symptoms after gluten in coeliac disease. Standardised bolus gluten food challenge and interleukin-2 assessment could provide a valuable clinical test to monitor and diagnose coeliac disease in patients established on a gluten-free diet.

Sex Difference in Celiac Disease in Undiagnosed Populations: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

A higher proportion of female vs male patients receive a diagnosis of celiac disease. Little is known about sex-based differences in the prevalence of celiac disease in undiagnosed populations. We aimed to address this knowledge gap with a systematic review and meta-analysis.

METHODS

We searched MEDLINE, Embase, Cochrane, and Scopus databases through 2017 for studies of screen-detected or undiagnosed celiac disease. Our final analysis included studies that included screening and confirmatory tests (either second serologic analysis or a small intestine biopsy) and provided information on the sex of participants. Studies were excluded if they were performed with specific, high-risk, or referral populations. The primary outcome was the percentage of undetected celiac disease among female and male patients.

RESULTS

We identified 4070 articles and analyzed data from 87. Our meta-analysis comprised data from 291,969 study participants. The pooled prevalence of undetected celiac disease in female participants was 0.589% (95% CI, 0.549%-0.629%) and in male participants was 0.415% (95% CI, 0.343%-0.487%). The risk of undetected celiac disease was higher among female than male participants (relative risk [RR], 1.42; 95% CI, 1.27-1.57; P < .00001). The I² was 5% (low heterogeneity among studies). In subgroup analyses, the RR of celiac disease for girls vs boys was 1.79 (95% CI, 1.44-2.22; P < .00001; I² = 18%), the RR for female vs male blood donors was 1.13 (95% CI, 0.76-1.69; P = .54; I² = 0), and the RR for women vs men with villous atrophy was 1.38 (95% CI, 1.07-1.79; P = .01; I² = 0).

CONCLUSIONS

In a systematic review and meta-analysis, we found a higher risk for celiac disease in women than men in an undiagnosed populations (identified through general population screening). The increased risk for celiac disease among girls and women should be considered for screening, diagnosis, and management strategies.

How to manage adult coeliac disease: perspective from the NHS England Rare Diseases Collaborative Network for Non-Responsive and Refractory Coeliac Disease

Adult coeliac disease (CD) affects approximately 1% of the population. Most patients diagnosed will respond to a gluten-free diet; however, up to 30% may have persisting symptoms. Such patients may have ongoing issues associated with adherence, non-responsive CD or refractory CD. This article provides a clinical overview of how to manage this group of patients with persisting symptoms, including an investigational algorithm and details of how to contact the National Health Service England Rare Diseases Collaborative Network for Non-Responsive and Refractory Coeliac Disease. We hope this will be a valuable source of contemporary information for all UK gastroenterologists and internationally.

HLA Haplotype Association with Celiac Disease in Albanian Pediatric Patients from Kosovo

Genetic predisposition to celiac disease (CD) is strongly associated with the presence of HLA alleles in the individual genotype encoding HLA-DQ2 and/or HLA-DQ8 heterodimers. The main aim of this study was to analyze the HLA-A, -B, -DRB1, and -DQ allele and five-locus haplotype frequencies in 60 Albanian pediatric CD patients and 124 non-CD children from Kosovo. The most prevalent haplotype in patients was the ancestral AH 8.1 haplotype present in 22.5% of the cases compared to 2.8% of the controls (P < 0.0001). Additionally, two other haplotypes were also overrepresented in patients (HLA-A^∗02~B^∗50~DRB1^∗07~DQA1^∗02:01~DQB1^∗02:02 and HLA-A^∗68~B^∗44~DRB1^∗07~DQA1^∗02:01~DQB1^∗02:02). Analysis showed that 95.0% of CD patients and 43.3% of controls were carriers of HLA-DQ2 and/or HLA-DQ8 heterodimers. The most frequent CD-predisposing HLA-DQ haplotypes in patients were HLA-DQ2.5 (46.7%) and HLA-DQ2.2 (11.6%), while the most prevalent genotypes were HLA-DQ2.5/DQX (58.3%) and HLA-DQ2.5/DQ2.2 (20.0%). The frequency of the HLA-DQ8 heterodimer among CD patients (4.2%) compared to the control group (8.1%) was without statistical significance. The given data demonstrate differences in the distribution of HLA haplotypes among Albanian CD patients from Kosovo in comparison to other European and non-European populations, as well as provide additional population data to supplement the thus far undisputed importance of the role of HLA-DQ2 and HLA-DQ8 heterodimers in the development of CD.

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.

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.

Wheat Intolerance and Chronic Gastrointestinal Symptoms in an Australian Population-based Study: Association Between Wheat Sensitivity, Celiac Disease and Functional Gastrointestinal Disorders

OBJECTIVES

Wheat avoidance in the absence of celiac disease (CD) is common but occurrence of concurrent functional gastrointestinal disorders (FGIDs) in this group is uncertain. The aims of this study were to determine the prevalence of self-reported wheat or gluten sensitivity and doctor diagnosed CD in an Australian population, define the associated gastrointestinal (GI) symptoms and FGIDs, and determine the relationship between self-reported wheat sensitivity, demographic and medical factors.

METHODS

A total of 3542 people randomly selected from the Australian population returned a mail survey which contained questions on wheat avoidance, GI symptoms, demographic, medical, and lifestyle factors. We defined self-reported wheat sensitivity as people who reported gastrointestinal symptoms on ingestion of wheat based foods, but did not suffer from celiac disease, inflammatory bowel disease or colorectal cancer. Functional dyspepsia (FD) and irritable bowel syndrome (IBS) were diagnosed by Rome III criteria. CD status was self-reported.

RESULTS

The prevalence of self-reported wheat sensitivity in this cohort was 14.9% (95% CI 13.7-16.2). The prevalence of CD was 1.2% (95%CI 0.8-1.6). Doctor diagnosed CD was significantly associated with a diagnosis of FD (OR 3.35, 95%CI 1.72-6.52) and IBS (OR 2.28, 95%CI 1.08-4.81). Those with self-reported wheat sensitivity were more likely to report multiple abdominal symptoms (of the 18 assessed) than those without (3.9 symptoms with self-reported wheat sensitivity vs. 1.6 without, p = 0.0001). In a multivariate analysis, self-reported wheat sensitivity was independently associated with IBS (OR 3.55, 95%CI 2.71-4.65) and FD (1.48, 95%CI 1.13-1.94).

CONCLUSIONS

Self-reported wheat sensitivity is common, with a prevalence of 14.9% in this cohort. There is a strong association between both celiac disease and self-reported wheat sensitivity, and chronic gastrointestinal symptoms, as well as a diagnosis of FD and IBS.

Food knowledge and psychological state predict adherence to a gluten-free diet in a survey of 5310 Australians and New Zealanders with coeliac disease

BACKGROUND

A gluten-free diet treats coeliac disease, but its efficacy depends on strict adherence. A variety of patient factors may influence adherence but have not been well described at a population level.

AIM

To comprehensively assess the patient factors that influence gluten-free diet adherence in patients with coeliac disease.

METHODS

Patients with coeliac disease completed an online survey comprising the validated Celiac Dietary Adherence Test in addition to data on demographics, details of diagnosis and management and assessment of diet knowledge, quality of life and psychological distress. Survey data were analysed for predictors of adherence and quality of life.

RESULTS

Of 7393 responses, 5310 completed the Celiac Dietary Adherence Test and 3230 (61%) were adherent to a gluten-free diet. Multivariate regression showed older age, being male, symptoms after gluten ingestion, better food knowledge and lower risk of psychological distress were independent predictors of adherence (each P ≤ 0.008). Additionally, dietary adherence was associated with better quality of life (P < 0.001; multiple regression). Respondents who considered themselves to have poor food knowledge were more likely to incorrectly identify gluten-free foods, but could still recognise gluten-containing foods, suggesting that poor knowledge may lead to over-restriction of diet.

CONCLUSIONS

Poor knowledge of a gluten-free diet and psychological wellbeing were independent modifiable risk factors for inadequate adherence to a gluten-free diet in patients with coeliac disease. Involvement of both a dietitian and mental health care professional, in the presence of psychological distress, is likely to be necessary to improve adherence and health outcomes.

A Serological Diagnosis of Coeliac Disease Is Associated with Osteoporosis in Older Australian Adults

Previously thought to be mainly a disorder of childhood and early adult life, coeliac disease (CeD) is increasingly diagnosed in older adults. This may be important given the association between CeD and osteoporosis. The primary aim of this study was to determine the seroprevalence of undiagnosed CeD (‘at-risk serology’) in an older Australian community and relate this to a diagnosis of osteoporosis and fractures during a follow-up period of 12 years. We included participants from the Hunter Community Study (2004–2007) aged 55–85, who had anti-tissue transglutaminase (tTG) titres, human leukocyte antigen (HLA) genotypes, and bone mineral density measurements at baseline. Follow-up data included subsequent diagnosis of CeD and fractures using hospital information. ‘At-risk’ serology was defined as both tTG and HLA positivity. Complete results were obtained from 2122 patients. The prevalence of ‘at-risk’ serology was 5%. At baseline, 3.4% fulfilled criteria for a diagnosis of osteoporosis. During a mean of 9.7 years of follow-up, 7.4% of the cohort suffered at least one fracture and 0.7% were subsequently diagnosed with CeD. At-risk serology was significantly associated with osteoporosis in a multivariate model (odds ratio 2.83, 95% confidence interval 1.29–6.22); there was insufficient power to look at the outcome of fractures. The results of this study demonstrate that at-risk CeD serology was significantly associated with concurrent osteoporosis but not future fractures. Most individuals with a serological diagnosis of CeD were not diagnosed with CeD during the follow-up period according to medical records. Coeliac disease likely remains under-diagnosed.

High rates of variation in HLA-DQ2/DQ8 testing for coeliac disease: results from an RCPAQAP pilot program

AIM

Coeliac disease(CD) is a highly prevalent, gluten-dependent, autoimmune enteropathy. While the diagnosis is based on serological and histological criteria, genotyping of the human leucocyte antigens (HLA) DQ2 and DQ8 has been shown to have substantial clinical utility, especially in excluding the diagnosis in patients who do not carry either antigen. As a result, HLA genotyping is now being performed by more laboratories and has recently become one of the most frequently requested genetic tests in Australia. To date, there has been little scrutiny on the accuracy and reporting of results by laboratories new to HLA typing. In response to clinician feedback that identified potentially clinically significant discrepancies in HLA typing results, the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) undertook a pilot study to assess laboratory performance in the detection of HLA-DQ2/DQ8 and their associated HLA-DQA1 and HLA-DQB1 alleles.

METHODS

DNA was extracted from 5 patients and sent to 10 laboratories for external quality assurance (EQA) testing. Laboratories were assessed for reporting in genotyping, interpretation and methodology.

RESULTS

Our findings showed that at least 80% of laboratories underperform with respect to recommended guidelines for HLA typing and reporting for CD, with 40% of laboratories failing to provide any clinical interpretation or full genotyping data. This suboptimal level of reporting may lead to ambiguities for downstream clinical interpretation that may compromise patient management.

CONCLUSIONS

These findings highlight the importance of adherence to standardised guidelines for optimal performance and reporting of HLA results and substantiate the need for EQA and proficiency testing for laboratories providing this service.

PREVALENCE OF CELIAC DISEASE PREDISPOSING GENOTYPES, INCLUDING HLA-DQ2.2 VARIANT, IN BRAZILIAN CHILDREN

BACKGROUND

Celiac disease is an autoimmune enteropathy triggered by the ingestion of gluten in genetically susceptible individuals. Almost all celiac patients carry immune recognition genes coding for HLA-DQ2.5 and DQ8 heterodimers. Over the last few years, great importance has been given to HLA-DQ2.2 as probable predisposing variant, although controversies still exist regarding its relevance.

OBJECTIVE

The aim of our study was to determine the possible existence of an association between HLA-DQ2.2 and celiac disease in Brazilian children by analyzing the prevalence of the predisposing variants for celiac disease in a representative group of children of a population in which this determination is still missing.

METHODS

HLA-DQ typing was performed in samples from a group of celiac (n=100) and non-celiac children (n=110). All samples were tested for the presence of the following variants: DQA1*05-DQB1*02 (DQ2.5), DQA1*03-DQB1*03:02 (DQ8) and DQA1*02:01-DQB1*02:02 (DQ2.2). Fisher`s exact test was used for statistical analysis.

RESULTS

In the group of 100 celiac children, 78 (78%) were positive for DQ2, 13 (13 %) were DQ2/DQ8 and 6 (6%) were DQ8 positives. The HLA-DQ pattern in the 110 non-celiac children was as follows: positive for DQ2 in 33 (29.9%) samples, in 2 (1.8 %) was positive for DQ2/DQ8 and in 15 (13.6%) was positive for DQ8. We found significant differences between the distribution of some but not all of the analyzed alleles when comparing celiac and non-celiac children.

CONCLUSION

The genotyping of celiac disease HLA-DQ predisposing alleles showed similarities with HLA-DQ patterns found in both European and non-European populations, which may be a reflection of the miscegenation, which gave origin to the current Brazilian population. No significant association was found between DQ2.2 variant and celiac disease in the studied population.

Rapid, Loop-Mediated Isothermal Amplification Detection of Celiac Disease Risk Alleles

Human leukocyte antigen (HLA) genotyping has become a useful investigation in the diagnostic work-up of celiac disease (CD), with utility in risk stratification and screening. However, broad application of this technology has been hindered by the cost and time burden of conventional laboratory-based assays. We have developed and validated CD-loop-mediated isothermal amplification (CD-LAMP), a LAMP assay, which enables rapid identification of the signature CD risk genotypes, HLA-DQ2.5, HLA-DQ8, HLA-DQ2.2, and HLA-DQA1*05. Sample-to-answer is achieved in approximately 65 minutes without DNA purification, thermal cycling, or specialized analytical equipment. CD-LAMP genotyping of samples was 100% concordant with accredited pathology genotyping on a panel of 40 blood and 20 saliva samples. In a panel of 100 purified DNA samples, genotyping of the high-risk DQ2.5 genotype was 100% concordant with accredited pathology genotyping, with slightly reduced sensitivity for the DQ8 genotype (97.1%) and reduced specificity for the DQ8 (93.9%) and DQ2.2 (95.1%) genotypes. CD-LAMP results are easily visualized and instrument free through the addition of a DNA intercalating dye after amplification. Combined with point-of-care antibody testing, CD-LAMP may enable immediate, confident CD diagnosis at a low cost in the clinical setting.

Resolving incomplete single nucleotide polymorphism tagging of HLA-DQ2.2 for coeliac disease genotyping using digital droplet PCR

A hallmark of coeliac disease (CD) is the exceptionally strong genetic association with HLA-DQ2.5, DQ8, and DQ2.2. HLA typing provides information on CD risk important to both clinicians and researchers. A method that enables simple and fast detection of all CD risk genotypes is particularly desirable for the study of large populations. Single nucleotide polymorphism (SNP)-based HLA typing can detect the CD risk genotypes by detecting a combination of six SNPs but this approach can struggle to resolve HLA-DQ2.2, seen in 4% of European CD patients, because of the low resolution of one negatively predicting SNP. We sought to optimise SNP-based HLA typing by harnessing the additional resolution of digital droplet PCR to resolve HLA-DQ2.2. Here we test this two-step approach in an unselected sample of Mexican DNA and compare its accuracy to DNA typed using traditional exon detection. The addition of digital droplet PCR for samples requiring negative prediction of HLA-DQ2.2 enabled HLA-DQ2.2 to be accurately typed. This technique is a simple addition to a SNP-based typing strategy and enables comprehensive definition of all at-risk HLA genotypes in CD in a timely and cost-effective manner.

Celiac Disease: A Review of Current Concepts in Pathogenesis, Prevention, and Novel Therapies

Our understanding of celiac disease and how it develops has evolved significantly over the last half century. Although traditionally viewed as a pediatric illness characterized by malabsorption, it is now better seen as an immune illness with systemic manifestations affecting all ages. Population studies reveal this global disease is common and, in many countries, increasing in prevalence. These studies underscore the importance of specific HLA susceptibility genes and gluten consumption in disease development and suggest that other genetic and environmental factors could also play a role. The emerging data on viral and bacterial microbe-host interactions and their alterations in celiac disease provides a plausible mechanism linking environmental risk and disease development. Although the inflammatory lesion of celiac disease is complex, the strong HLA association highlights a central role for pathogenic T cells responding to select gluten peptides that have now been defined for the most common genetic form of celiac disease. What remains less understood is how loss of tolerance to gluten occurs. New insights into celiac disease are now providing opportunities to intervene in its development, course, diagnosis, and treatment.

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.

Non-coeliac gluten or wheat sensitivity: emerging disease or misdiagnosis?

Non-coeliac gluten or wheat sensitivity (NCG/WS) is a condition characterised by adverse gastrointestinal and/or extra-intestinal symptoms associated with the ingestion of gluten- or wheat-containing foods, in the absence of coeliac disease or wheat allergy. Up to one in 100 people in Australia may have coeliac disease but many more report adverse gastrointestinal and/or extra-intestinal symptoms after eating wheat products. In the absence of validated biomarkers, a diagnosis of NCG/WS can only be made by a double-blind, placebo-controlled, dietary crossover challenge with gluten, which is difficult to apply in clinical practice. Of people self-reporting gluten or wheat sensitivity, only a small proportion (16%) will have reproducible symptoms after a blinded gluten challenge of gluten versus placebo in a crossover dietary trial and fulfil the current consensus criteria for a diagnosis of NCG/WS. A wide range of symptoms are associated with NCG/WS, including gastrointestinal, neurological, psychiatric, rheumatological and dermatological complaints. The pathogenesis of NCG/WS is not well understood, but the innate immune system has been implicated, and there is overlap with coeliac disease and the functional gastrointestinal disorders (irritable bowel syndrome and functional dyspepsia). Identification of NCG/WS is important as gluten-free diets carry risks, are socially restricting and are costlier than regular diets.

Coeliac disease: review of diagnosis and management

Coeliac disease is an immune-mediated systemic disease triggered by exposure to gluten, and manifested by small intestinal enteropathy and gastrointestinal and extra-intestinal symptoms. Recent guidelines recommend a concerted use of clear definitions of the disease. In Australia, the most recent estimated prevalence is 1.2% in adult men (1:86) and 1.9% in adult women (1:52). Active case finding is appropriate to diagnose coeliac disease in high risk groups. Diagnosis of coeliac disease is important to prevent nutritional deficiency and long term risk of gastrointestinal malignancy. The diagnosis of coeliac disease depends on clinico-pathological correlation: history, presence of antitransglutaminase antibodies, and characteristic histological features on duodenal biopsy (when the patient is on a gluten-containing diet). Human leucocyte antigen class II haplotypes DQ2 or DQ8 are found in nearly all patients with coeliac disease, but are highly prevalent in the general population at large (56% in Australia) and testing can only exclude coeliac disease for individuals with non-permissive haplotypes. Adhering to a gluten free diet allows duodenal mucosal healing and alleviates symptoms. Patients should be followed up with a yearly review of dietary adherence and a health check. Non-coeliac gluten or wheat protein sensitivity is a syndrome characterised by both gastrointestinal and extra-intestinal symptoms related to the ingestion of gluten and possibly other wheat proteins in people who do not have coeliac disease or wheat allergy recognised by diagnostic tests.