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

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.

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.

Influence of Age and Type 1 Diabetes Mellitus on Serological Test for Celiac Disease in Children

PURPOSE

Serological tests of tissue transglutaminase (TTG) and deamidated gliadin (DGP) antibodies for celiac disease diagnosis show conflicting correlation with histology in young children and in type 1 diabetes mellitus (T1DM). Tests' ability to predict histology and cutoff values based on age and T1DM was evaluated.

METHODS

A retrospective study of children who had celiac serological tests between 6/1/2002 and 12/31/2014 at a pediatric hospital.

RESULTS

TTG IgA displayed similar results in predicting histology between <4.0 and ≥4.0 years age groups with sensitivity 98% and 93%, and specificity 88% and 86%, respectively. In children <4.0 years old, sensitivity for DGP antibodies was 100% and specificity 94%; in ≥4.0 years age groups, sensitivity was 60%, 88% for DGP IgA and IgG and specificity 95%, 96%, respectively. TTG IgA had low specificity in patients with T1DM compared with non-T1DM, 42% vs. 91%. Positive TTG IgA with normal histology was associated with higher T1DM prevalence at 36% compared with negative tests at 4%. Finally, the TTG IgA cutoff value was higher in T1DM at 36 vs. 16.3 units in non-T1DM. DGP IgG cutoff showed similar values between age groups; TTG IgA and DGP IgA cutoffs were lower in <4.0 years at 8.3 and 11.9 units than ≥4.0 years at 23.4 and 19.9, respectively.

CONCLUSION

TTG IgA is sufficient for the <4.0 years age group and DGP antibodies had no advantage over TTG IgA in older children. The cutoff value to determine a positive TTG IgA should be higher for children with T1DM.

The Predictive Value of Serum Cytokines for Distinguishing Celiac Disease from Non-Celiac Gluten Sensitivity and Healthy Subjects

Background

It has been established that the level of some inflammatory cytokines increases in celiac disease (CD) and non-celiac gluten sensitivity (NCGS) in comparison with healthy subjects. Therefore, the primary interest in our research was proposing an accurate tool to diagnose patients with CD and NCGS from healthy individuals in an Iranian population.

Methods

The serum samples were examined in 171 participants, including 110 CD patients, 46 healthy individuals, and 15 NCGS. The commercial ELISA kits were used to detect the level of the following cytokines: IL-1, IL-6, IL-8, IL-15, and IFN-γ. The receiver operating characteristic (ROC) curve analysis was applied to determine the optimal thresholds for high sensitivity, specificity, positive and negative predictive values of cytokines, as the indicators of CD, NCGS, and healthy control groups.

Results

In NCGS group, the values of area under the ROC curve for IL-1, IL-8, and IFN-γ were 71%, 78%, and 70%, respectively. To differentiate the CD and NCGS groups from the control group, IL-15 had the highest sensitivity (82.70%), specificity (56.50%), positive predictive value (81.98%), and negative predictive value (57.78%), followed by IL-8 with the highest sensitivity of 74.50%, specificity of 73.30%, and positive and negative predictive values of 95.35% and 30.21%, respectively.

Conclusion

The obtained results demonstrate that IL-15 and IL-8 could be proposed as potential markers in their optimal cut-off points for distinguishing CD from the NCGS and the healthy control. Based on our findings, the evaluation of cytokine levels can be recommended as a useful tool for the diagnosis of CD and NCGS in a clinical practice.

Carrier frequency of HLA-DQB1*02 allele in patients affected with celiac disease: A systematic review assessing the potential rationale of a targeted allelic genotyping as a first-line screening

BACKGROUND

Celiac Disease (CD) is an immune-mediated disorder, in which the HLA immunogenetic background (DQ2 and DQ8 heterodimers) and environmental trigger (gluten) are well established. Indeed, both factors are necessary – but not sufficient – to develop CD. However, it is very likely that CD is underdiagnosed in both developing and developed countries, due to several aspects, including the fact that a lot of patients present mild and/or atypical symptoms, without the presence of any recognized risk factors. Therefore, the possibility and feasibility of widened screening strategies to identify CD patients are debated.

AIM

To provide further evidence of the main epidemiological importance of HLA-DQB1*02 allele in the population of CD patients.

METHODS

We performed a systematic search in PubMed, EMBASE, Cochrane, Web of Science and Scopus databases, in order to produce a systematic review assessing the carrier frequency of HLA-DQB1*02 allele in the celiac population. Following the PRISMA guidelines, we retrieved all the original articles describing CD patients’ HLA-DQB1 genotype in such a way that could allow to assess the HLA-DQB1*02 carrier frequency among CD patients, along with the evidence of the appropriate diagnostic work-up to achieve a correct and final diagnosis of CD.

RESULTS

The final output of this systematic search in the medical literature consisted of 38 studies providing the appropriate HLA-DQB1 genotype information of the respective CD population. According to this systematic review, including a pool of 4945 HLA-DQ genotyped CD patients, the HLA-DQB1*02 carrier frequency was 94.94%, meaning that only 5.06% of CD patients were completely lacking this allelic variant. Interestingly, if we consider only the studies whereby the prevalence of CD patients affected with type 1 diabetes mellitus was supposed or clearly established to be very low, the frequency of non-HLA-DQB1*02 carriers among CD patients dropped to 3.65%.

CONCLUSION

Such a high carrier frequency of the HLA-DQB1*02 allelic variant (which is > 95%-96% in CD patients without risk factors, like type 1 diabetes mellitus comorbidity) might be exploited to consider a cost-effective and widened screening approach. If a sustainable strategy could be implemented through a low-cost targeted genetic test to detect the individual presence of HLA-DQB1*02 allele, an appropriate algorithm for serological screening in individuals resulting to be genetically predisposed to CD, might be considered.

Celiac Disease in Brazilian First-degree Relatives: The Odds Are Five Times Greater for HLA DQ2 Homozygous

First-degree relatives (FDRs) of 47 outpatients with celiac disease (CD) answered a questionnaire about symptoms related to CD and were investigated for human leukocyte antigen (HLA)-DQ2, DQB102 homozygosis, and DQ8 alleles. Genetically susceptible individuals were tested for antitransglutaminase antibody immunoglobulin A. Seropositive FDR underwent small bowel biopsies.From 114 FDR, 74.5% (n = 85) were positive for DQ2, DQ8, or both haplotypes. Homozygosity of DQB102 was found in 11.4% (n = 13) individuals. Three FDR were previously diagnosed with CD. Among the genetically susceptible individuals, 67.1% had at least 1 symptom related to CD. Seropositivity was 8/82 (9.8%), and 4/8 biopsies were compatible with CD. Therefore, the total number of FDR with CD was 6.1% (7/114), 95% confidence interval (1.71, 10.49). Three out of 7 FDR with CD were HLA DQB102 homozygous. The odds of being CD is 5 times, 95% confidence interval (0.99, 26.23), greater for HLA DQ B102 homozygous in FDR.

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.

Presence of DQ2.2 Associated with DQ2.5 Increases the Risk for Celiac Disease

Background. Celiac disease (CD) is a genetically determined immune-mediated disorder in which gluten immunogenic peptides are presented to CD4 T cells by HLA-DQ2.5, DQ8, DQ2.2, and their combinations. Our aim is to establish a risk gradient for celiac disease based on HLA-DQ profile in a brazilian representative population and the relevance of DQ2.2 in celiac disease development. Materials and Methods. 237 celiac patients and 237 controls (both groups with 164 females and 73 males) were included. All samples were tested for the presence of predisposing HLA-DQ alleles using the PCR-SSP method. Results were considered significant when p < 0.05. Disease risk was expressed as 1 : N for each HLA-DQ category described at this study. Results. DQ2.5 and/or DQ8 were detected in 224 celiac patients (94.5%) and 84 controls (35.4%). Eight celiac patients (3.4%) and 38 controls (16%) disclosed only DQ2.2. Even though DQ2.2 (β2/β2 or β2/x) showed a low CD risk of 1 : 251 and 1 : 550, respectively, the genotype DQ2.5/DQ2.2 (β2/β2) showed high CD risk of 1 : 10 (p < 0.0001). The disease risk gradient ranged from 1 : 3014 to 1 : 7. Conclusion. Our study allowed the determination of a risk gradient for celiac disease development in at-risk population, showing that DQ2.2 variant was relevant when associated with DQ2.5.

Extraintestinal manifestations of celiac disease: 33-mer gliadin binding to glutamate receptor GRINA as a new explanation

We propose a biochemical mechanism for celiac disease and non-celiac gluten sensitivity that may rationalize many of the extradigestive disorders not explained by the current immunogenetic model. Our hypothesis is based on the homology between the 33-mer gliadin peptide and a component of the NMDA glutamate receptor ion channel - the human GRINA protein - using BLASTP software. Based on this homology the 33-mer may act as a natural antagonist interfering with the normal interactions of GRINA and its partners. The theory is supported by numerous independent data from the literature, and provides a mechanistic link with otherwise unrelated disorders, such as cleft lip and palate, thyroid dysfunction, restless legs syndrome, depression, ataxia, hearing loss, fibromyalgia, dermatitis herpetiformis, schizophrenia, toxoplasmosis, anemia, osteopenia, Fabry disease, Barret's adenocarcinoma, neuroblastoma, urinary incontinence, recurrent miscarriage, cardiac anomalies, reduced risk of breast cancer, stiff person syndrome, etc. The hypothesis also anticipates better animal models, and has the potential to open new avenues of research.

Prevalence of celiac disease among first-degree relatives of Indian celiac disease patients

BACKGROUND

Celiac disease, once thought to be uncommon in Asia, is now recognized in Asian nations as well. We investigated the prevalence of celiac disease in first-degree relatives of celiac disease patients followed in our centre.

METHODS

First-degree relatives were screened prospectively for celiac disease using questionnaire-based interview and anti-tissue transglutaminase antibody. Serology positive first-degree relatives underwent duodenal biopsies. Diagnosis of celiac disease was made based on positive serology and villous abnormality Marsh grade 2 or higher. Human leucocyte antigen DQ2/-DQ8 was also assessed in 127 first-degree relatives.

RESULTS

434 first-degree relatives of 176 celiac disease patients were prospectively recruited; 282 were symptomatic (64.9%), 58 were positive for serology (13.3%). Seroprevalence was higher in female than in males (19% vs 8.5%; p=0.001) and highest in siblings (16.9%) than parents (13.6%) and children (5.9%) of celiac patients (p=0.055); 87.4% first-degree relatives were human leucocyte antigen-DQ2/-DQ8 positive. Overall prevalence of celiac disease was 10.9% amongst first-degree relatives.

CONCLUSIONS

The prevalence of celiac disease in first-degree relatives of celiac disease patients was 10.9% in our cohort, and 87% had human leucocyte antigen-DQ2 or -DQ8 haplotype. All first-degree relatives of celiac disease patients should be screen for celiac disease even if asymptomatic or with atypical manifestations.

Suggestions for automatic quantitation of endoscopic image analysis to improve detection of small intestinal pathology in celiac disease patients

Although many groups have attempted to develop an automated computerized method to detect pathology of the small intestinal mucosa caused by celiac disease, the efforts have thus far failed. This is due in part to the occult presence of the disease. When pathological evidence of celiac disease exists in the small bowel it is visually often patchy and subtle. Due to presence of extraneous substances such as air bubbles and opaque fluids, the use of computerized automation methods have only been partially successful in detecting the hallmarks of the disease in the small intestine-villous atrophy, fissuring, and a mottled appearance. By using a variety of computerized techniques and assigning a weight or vote to each technique, it is possible to improve the detection of abnormal regions which are indicative of celiac disease, and of treatment progress in diagnosed patients. Herein a paradigm is suggested for improving the efficacy of automated methods for measuring celiac disease manifestation in the small intestinal mucosa. The suggestions are applicable to both standard and videocapsule endoscopic imaging, since both methods could potentially benefit from computerized quantitation to improve celiac disease diagnosis.