The involvement of the HLA-DQB1 alleles in the risk and the severity of Iranian coeliac disease patients

Association of the HLA-DQB1*02 allele with lower tauopathy in Alzheimer's disease

Although many studies have investigated the influence of HLA on the risk of Alzheimer's Disease (AD), there have been inconsistent results. Part of this problem has been attributed to limitations of a clinical assessment in the absence of histopathological confirmation or other quantitative assessments. This study employed a subset of the AD Sequencing Project, representing 2663 cases with histopathological confirmation of AD and confirmation of 881 cognitively normal cases. Two HLA allelic subtypes, DQB1*02:01 and DQB1*02:02, were associated with lower Braak staging, a measure of tauopathy in the brain. These HLA subtypes were also associated with a later age of onset. There was a lower occurrence of HLA-DQB1*02:01 and HLA-DQB1*02:02 in AD cases compared to cognitively normal cases. For all of the above results, replicative sets were confirmatory. The above results were also maintained for both HLA-DQB1*02:01 and HLA-DQB1*02:02 when removing the effect of APOE4 or APOE2. Interestingly, the HLA-DQB1*02 allele binds tau better than all other HLA-DQB1 alleles tested, per an in silico assessment, raising the question of whether deletion of tau binding, auto-reactive T-cells in the thymus could reduce the likelihood of the onset of AD?

Association of HLA-DQ4/5 genotype polymorphisms with celiac disease in a group of children in Southwest Iran: A case-control study

Background and Aim

Celiac disease (CD) has proinflammatory and pathogenic immune responses to gluten in intestinal tissue, leading to structural changes in the mucosa of the small intestine. The association of human leukocyte antigen (HLA)-DQ2 and DQ8 genotypes with CD has been previously reported. This test has a negative predictive value close to 100%, so its main purpose is to rule out the detection of CD completely or almost completely. There is limited information regarding HLA-DQ4/5 in CD. This study was conducted to determine the HLA-DQ4/5 genotypes in a group of Southwestern Iranian children with CD.

Methods

We conducted a case-control study in Southwest Iran involving 100 participants, employing a nonprobabilistic sampling method. Samples were taken from participants' oral buccal mucosa at Imam Sajjad Hospital of Yasuj, Iran. Then DNA was extracted from these samples and used to determine the frequency of HLA-DQ4/5 genotypes through Sequence-Specific Primer-Polymerase Chain Reaction assay. SPSS 20 was utilized for statistical analyses.

Results

Fifty diagnosed patients with CD (high anti-tissue transglutaminase [tTG]-IgA level [upper limit of normal] with pathological findings of Marsh III) and 50 non-CD individuals (normal anti-tTG-IgA level and normal total IgA level) were enrolled in the study from August 5, 2022 to October 15, 2023. Findings showed that the DQ4a*4b allele has the highest frequency in the CD samples (78%, p < 0.01) followed by the DQ5a*5b allele (12%, p < 0.01). Additionally, there was a higher prevalence of DQ4/DQ5 in patients with CD compared to controls (odds ratio = 6.5, confidence interval = 0.84 to 69.46, p < 0.01). Furthermore, a significant association was found among HLA DQ4/5 genotype, age (>9.5) (p < 0.01), and gender (female) (p < 0.05).

Conclusion

The observed significant differences among HLA-DQ4 and HLA-DQ5 in Iranian CD samples against controls and the high value of the relative risks showed the significant function of the studied alleles in the prevalence of CD in Iranian patients.

Human leukocyte antigen system associations in Malassezia-related skin diseases

BACKGROUND

The human leukocyte antigen system (HLA) is divided into two classes involved in antigen presentation: class I presenting intracellular antigens and class II presenting extracellular antigens. While susceptibility to infections is correlated with the HLA system, data on associations between HLA genotypes and Malassezia-related skin diseases (MRSD) are lacking. Thus, the objective of this study was to investigate associations between HLA alleles and MRSD.

MATERIALS AND METHODS

Participants in The Danish Blood Donor Study (2010-2018) provided questionnaire data on life style, anthropometric measures, and registry data on filled prescriptions. Genotyping was done using Illumina Infinium Global Screening Array, and HLA alleles were imputed using the HIBAG algorithm. Cases and controls were defined using filled prescriptions on topical ketoconazole 2% as a proxy of MRSD. Logistic regressions assessed associations between HLA alleles and MRSD adjusted for confounders and Bonferroni corrected for multiple tests.

RESULTS

A total of 9455 participants were considered MRSD cases and 24,144 participants as controls. We identified four risk alleles B*57:01, OR 1.19 (95% CI: 1.09-1.31), C*01:02, OR 1.19 (95% CI: 1.08-1.32), C*06:02, OR 1.14 (95% CI: 1.08-1.22), and DRB1*01:01, OR 1.10 (95% CI: 1.04-1.17), and two protective alleles, DQB1*02:01, OR 0.89 (95% CI: 0.85-0.94), and DRB1*03:01, OR 0.89 (95% CI: 0.85-0.94).

CONCLUSION

Five novel associations between HLA alleles and MRSD were identified in our cohort, and one previous association was confirmed. Future studies should assess the correlation between Malassezia antigens and antigen-binding properties of the associated HLA alleles.

Diversity of HLA class I and class II alleles in Iran populations: Systematic review and Meta-Analaysis

The human leukocyte antigen (HLA) system plays an essential role in the peptides antigen presentation and more regulation of immune responses. Regarding all HLA molecules' associations with various diseases and their clinical utilities in understanding drug reactions or prediction of transplantation outcome, there is a need for much more extensive HLA data generated from Asian countries.

METHOD

A comprehensive search was conducted in electronic databases between 1990 and 2021 to identify relevant articles to HLA frequency in the normal Iranian population. Two independent reviewers screened and selected the eligible studies. After data extraction, the meta-analysis was performed using STATA version 14. The overall frequencies and their 95% confidence intervals (CIs) were obtained using the random-effects model.

RESULTS

Among 1141 studies 78 were eligible for this study and the sample sizes varied from 14 to 15,600. The most frequent alleles of HLA class I were HLA-A*02 (22%; 95%CI: 20-24%; I² = 88.63%), -B*35 (18%; 95%CI: 16-21%; I² = 90.95%), -C*12 (18%; 95%CI: 13-22%; I² = 89.51%). HLA-DQA1*01 (42%; 95%CI: 40-44%; I² = 56.80%), -DQB1*03 (38%; 95%CI: 35-42%; I² = 92.38%), and -DRB1*11 (24%; 95%CI: 22-26%; I² = 90.72%) were the most frequent alleles of HLA class II in Iran.

DISCUSSION

Our meta-analysis results point out that the comprehensive report of HLA allele frequency in the Iranian population could be helpful as reference data for planning and managing transplantation and immune disease treatment in Iran.

The spectrum of association in HLA region with rheumatoid arthritis in a diverse Asian population: evidence from the MyEIRA case-control study

BACKGROUND

Fine-mapping of human leukocyte antigen (HLA) region for rheumatoid arthritis (RA) risk factors has identified several HLA alleles and its corresponding amino acid residues as independent signals (i.e., HLA-A, HLA-B, HLA-DPB1, and HLA-DQA1 genes), in addition to the well-established genetic factor in HLA-DRB1 gene. However, this was mainly performed in the Caucasian and East Asian populations, and data from different Asian regions is less represented. We aimed to evaluate whether there are independent RA risk variants in both anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA patients from the multi-ethnic Malaysian population, using the fine-mapping of HLA region strategy.

METHODS

We imputed the classical HLA alleles, amino acids, and haplotypes using the Immunochip genotyping data of 1260 RA cases (i.e., 530 Malays, 259 Chinese, 412 Indians, and 59 mixed ethnicities) and 1571 controls (i.e., 981 Malays, 205 Chinese, 297 Indians, and 87 mixed ethnicities) from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA) population-based case-control study. Stepwise logistic regression was performed to identify the independent genetic risk factors for RA within the HLA region.

RESULTS

We confirmed that the HLA-DRB1 amino acid at position 11 with valine residue conferred the strongest risk effect for ACPA-positive RA (OR = 4.26, 95% CI = 3.30-5.49, P_GWAS = 7.22 × 10^-29) in the Malays. Our study also revealed that HLA-DRB1 amino acid at position 96 with histidine residue was negatively associated with the risk of developing ACPA-positive RA in the Indians (OR = 0.48, 95% CI = 0.37-0.62, P_GWAS = 2.58 × 10^-08). Interestingly, we observed that HLA-DQB1*03:02 allele was inversely related to the risk of developing ACPA-positive RA in the Malays (OR = 0.17, 95% CI = 0.09-0.30, P_GWAS = 1.60 × 10^-09). No association was observed between the HLA variants and risk of developing ACPA-negative RA in any of the three major ethnic groups in Malaysia.

CONCLUSIONS

Our results demonstrate that the RA-associated genetic factors in the multi-ethnic Malaysian population are similar to those in the Caucasian population, despite significant differences in the genetic architecture of HLA region across populations. A novel and distinct independent association between the HLA-DQB1*03:02 allele and ACPA-positive RA was observed in the Malays. In common with the Caucasian population, there is little risk from HLA region for ACPA-negative RA.

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.

HLA-DQ2/DQ8 frequency in adult patients with celiac disease, their first-degree relatives, and normal population in Turkey

BACKGROUND/AIMS

Celiac disease is an autoimmune, familial disease that results in susceptibility to gluten in cereal and cereal products in genetically susceptible individuals. The aim of the present study was to investigate the presence of HLA-DQ2/DQ8 in patients with celiac disease, their first-degree relatives, and healthy community.

MATERIALS AND METHODS

HLA-DQ2/DQ8 analysis was performed in adult patients with celiac disease >18 years old (94 patients), their first-degree relatives (89 people), and healthy group (102 individuals). Anemia, osteoporosis, and diarrhea were interrogated in the celiac patient group and also anti-tissue transglutaminase, anti-endomysium, and anti-gliadin antibodies were recorded.

RESULTS

There was a significant relationship between HLA-DQ2/DQ8 presence in all groups, and the distribution of HLA-DQ2/DQ8 in all groups was different (p=0.000). No statistically significant correlation was found between the HLA tissue groups and diarrhea (p=0.087), osteoporosis (p=0.215), anemia (p=1.000), tissue transglutaminase antibodies (p=0.295), anti-gliadin antibodies (p=0.104), and anti-endomysium antibodies (p=0.243) in the celiac patient group.

CONCLUSION

HLA-DQ2/DQ8 can be used to diagnose celiac disease particularly when the tests are useless and to screen first-degree relatives.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

HLA-DQ2 homozygosis increases tTGA levels at diagnosis but does not influence the clinical phenotype of coeliac disease: A multicentre study

BACKGROUND AND PURPOSE

Magnitude of gluten-specific T-cell responses in coeliac disease (CD) might be dependent on HLA-DQ2 gene dose. We aimed to investigate the effects of HLA-DQB1*02 allele dose on clinical outcomes.

METHODS

We reviewed the charts of all coeliac patients attending to three Hungarian university clinics after 1997 and included those patients, who (a) were diagnosed with CD, (b) underwent high-resolution HLA typing and (c) were ≥18 years at the time of data collection. HLA typing was performed to determine DQB1*02 allele dose. Patients were divided into risk groups by DQB1*02 allele dose, as follows: high-, intermediate- and low-risk groups corresponded to a double, single and zero doses, respectively. We used ANOVA and Pearson's chi-squared test to explore association between HLA risk and clinical variables.

RESULTS

A total of 727 coeliac patients attended the clinics but only 105 (14.4%) patients were eligible for inclusion. High, intermediate and low HLA risk patients comprised 35.3%, 52.3% and 12.3% of the study population, respectively. Double dose of HLA-DQB1*02 was more frequent in patient with high tTGA level (>10 times the upper limit of normal; p = 0.045). Gene dose was not associated with younger age at diagnosis (p = 0.549), gender (p = 0.739), more severe diagnostic histology (p = 0.318), more frequent classical presentation (p = 0.846), anaemia (p = 0.611), metabolic bone disease (p = 0.374), dermatitis herpetiformis (p = 0.381) and autoimmune diseases (p = 0.837).

CONCLUSIONS

Our study shows a significant gene dose effect in terms of tTGA level at diagnosis, but no significant association between HLA-DQB1*02 allele dose and the clinical outcomes in CD.

Classical celiac disease is more frequent with a double dose of HLA-DQB1*02: A systematic review with meta-analysis

BACKGROUND AND AIMS

Experimental data suggest that the HLA-DQ2 gene dose has a strong quantitative effect on clinical outcomes and severity of celiac disease (CD). We aimed to conduct a meta-analysis with systematic review to investigate the association between HLA-DQB1*02 gene doses and the characteristics of CD.

METHODS

We searched seven medical databases for studies discussing HLA-DQB1 gene dose in CD and various disease characteristics, such as clinical presentation, histology, age at diagnosis, and comorbidities. Odds ratios (OR, for categorical variables) and weighted mean differences (for age) were calculated to compare patients with a double dose of HLA-DQB1*02 versus those with single and zero doses. Heterogeneity was tested with I2-statistics and explored by study subgroups (children and adults).

RESULTS

Twenty-four publications were eligible for meta-analysis. Classical CD was more frequent with a double versus single dose of the HLA-DQB1*02 allele (OR = 1.758, 95%CI: 1.148-2.692, I2 = 0.0%). In pediatric studies, gene dose effect was more prominent (OR = 2.082, 95%CI: 1.189-3.646, I2 = 0.0% and OR = 3.139, 95%CI: 1.142-8.630, I2 = 0.0% for the comparisons of double versus single and double versus zero dose, respectively). Atrophic histology was more prevalent with a double versus zero dose (OR = 2.626, CI: 1.060-6.505, I2 = 21.3%). We observed no gene dose effect regarding diarrhea, age at diagnosis, the severity of villous atrophy, and the association with type 1 diabetes mellitus.

CONCLUSION

A double dose of HLA-DQB1*02 gene seems to predispose patients to developing classical CD and villous atrophy. Risk stratification by HLA-DQB1*02 gene dose requires further clarification due to the limited available evidence.

HLA-DQ2 and -DQ8 genotype frequency in Syrian celiac disease children: HLA-DQ relative risks evaluation

Background

Celiac disease (CD) is a common autoimmune disease in Syria which manifesting with inflammation of the small intestine and with various extra intestinal symptoms. The disease is associated with human HLA-DQ genes encoding HLA-DQ2 and DQ8 proteins.

Methods

In this study, 49 children patients of CD and 58 healthy control samples were genotyped for HLA-DQ genes using SSP-PCR technique. Relative risks for different genotypes were also evaluated.

Results

The DQB1*0201 allele was the most common in the patients (77.6%) followed by DQB1*0302 allele (10.2%). The highest HLA-DQB risk for CD development was found in patients carriers a DQ2.5/DQ8 genotype (1/10), followed by the patients carriers DQ2.5/DQ2.5 (1/12).

Conclusion

The significant differences in the frequency of HLA-DQ2 and HLA-DQ8 in Syrian patients in compared with controls and relative risks predicted demonstrated the importance role of these alleles in the development of CD in Syrian children patients.

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.

HLA-DQ genetic risk gradient for type 1 diabetes and celiac disease in northwestern Mexico

BACKGROUND

Type 1 diabetes (T1D) and celiac disease (CD) are the 2 most common autoimmune childhood diseases that share their HLA-DQ2 and DQ8 genetic origin. There has currently been an increase in both diseases worldwide. In children from the low-population State of Sonora (15 inhabitants/km(2)) in north-western Mexico, there is no information on their genetic risk or the distribution of the related alleles in the general population.

AIMS

To compare the HLA-DQ allele frequency in a representative sample of newborns from Sonora with that of T1D and CD patients to determine the risk gradient, and to identify the presence of celiac autoimmunity in the T1D group.

METHODS

The study included 397 Sonoran newborns, with 44 cases of T1D, and 25 CD cases. The CD and T1D cases were clinically diagnosed by specialists at the Hospital Infantil del Estado de Sonora, and the autoantibodies were determined by ELISA. Whole blood was collected, gDNA was extracted, and HLA-DQ2 and DQ8 were typed by PCR-SSP. The risk gradient was calculated by comparing the allele frequencies of the cases with those of the newborns.

RESULTS

The Sonoran HLA-DQ risk heterodimer proportion was 16.1% for HLA-DQ2 and 13.6% for HLA-DQ8, with an HLA-DQ2:HLA-DQ8 ratio of 1.2:1. The DQ8/DQ2 genotype represented a 1:14 risk for T1D, whereas the DQ8/DQB1*0201 combination showed a 1:6 risk for CD. The prevalence of CD autoimmunity in T1D children was 7%.

CONCLUSION

The Sonoran population has a distinctive HLA-DQ allele distribution due to its ancestry. The HLA-DQ8 combinations with DQ2 or one of its alleles conferred the highest risk for both diseases, and T1D and CD frequently appear together.