HLA-DQ Alleles Research Articles

HLA DQ alleles and interleukin-10 polymorphism associated with Chlamydia trachomatis-related tubal factor infertility: a case-control study

The relationship between Chlamydia trachomatis tubal factor infertility (TFI) and the host's immunoregulatory genes was studied. Cell-mediated immune responses to C. trachomatis and chlamydial heat shock protein (CHSP60) were determined by lymphocyte proliferation assay. HLA-DQ alleles and interleukin-10 (IL-10) promoter polymorphism (-1082 A/G) were analysed in 52 TFI cases and in 61 controls by PCR. HLA-DQB1 or DQA1 alleles did not significantly differ between the TFI group and the control group. However, DQA1*0102 and DQB1*0602 alleles together with IL-10 -1082AA genotype were found significantly more frequently in the TFI patients than in the controls (0.18 and 0.02 respectively; P = 0.005). Five (22%) of the 23 patients who had a positive lymphocyte proliferative response to CHSP60 were positive also for IL-10 -1082AA and for the HLA-DQA1*0102 and HLA-DQB1*0602 alleles. Our results reveal an association of a cellular immune response to CHSP60, HLA class II alleles and IL-10 promoter genotypes in patients with chlamydial TFI.

Unbalanced amounts of HLA-DQA1 allele mRNA: DQA1*03 shows high and DQA1*0501 low amounts of mRNA in heterozygous individuals.

Genes of the HLA-DR, DQ region confer strong susceptibility to type 1 diabetes mellitus (IDDM). A possible mechanism of susceptibility is a difference in the amounts of transcripts of predisposing and neutral or protective haplotypes. In this study we developed an assay to compare the amounts of mRNA of two distinct HLA-DQA1 alleles in peripheral blood lymphocytes (PBLs) of heterozygous individuals, using a quantitative RT-PCR with an internal standard covering all HLA-DQA1 specifities. We also developed an algorithm to calculate the amounts of mRNA for two distinct alleles in heterozygous individuals based on the comparison to the same internal standard. In total, 37 HLA-DQA1 heterozygous individuals were analysed, including patients with IDDM (n = 14) and healthy controls (n = 23). Intra-individually, we observed different amounts of mRNA for different HLA-DQA1 alleles in the order: HLA-DQA1*03 > *01 > *0201 > *05. This order was observed in all individuals. We also observed a variation in the ratio of these unbalanced amounts of mRNA in individuals with the same HLA-DQA1 allele combinations. In all allele combinations the average ratio was increased in patients with IDDM compared to the control samples. HLA-DQA1*03 positive and DQA1*03, *05 heterozygous patients had the highest average ratios. Nevertheless, based on limited sample numbers, these differences did not reach significance. We therefore conclude that variations between HLA-DQA1 alleles are not limited to the nucleotide sequence but are also found at the level of amounts of mRNA.

Non-transmitted maternal HLA DQ2 or DQ8 alleles and risk of Type I diabetes in offspring: the importance of foetal or post partum exposure to diabetogenic molecules

Type I (insulin-dependent) diabetes mellitus results from an immune-mediated destruction of pancreatic beta cells for which HLA haplotypes DR3-DQ2 and DR4-DQ8 represent the strongest genetic risk markers. Mothers of patients with rheumatoid arthritis carry more frequently the HLA DR4-DQ8 haplotype as non-transmitted haplotype than mothers of healthy control subjects. As maternal cells have been shown to persist in their offspring up to 30 years after birth, we investigated whether the association of HLA DR3-DQ2 and DR4-DQ8 with Type I diabetes is purely a genetic effect acting through inheritance or whether it can also act as an environmental factor, for example through foetal exposure in utero to maternal circulating cells. We analysed the non-transmitted parental HLA DQ alleles of 464 families (1367 subjects) with a Type I diabetic offspring. HLA DQ alleles were assessed using sequence-specific primers and allele-specific oligonucleotides hybridisation. A chi-square test was done to compare allele and transmission frequencies in the respective subsets of families. The non-transmitted HLA DR3-DQ2 and DR4-DQ8 were more frequent in mothers than in fathers of all non- DQ2/DQ8 heterozygous diabetic offspring ( p=0.0001) as well as in offspring not carrying any HLA high-risk allele ( p=0.0243). In patients with either risk allele alone, more maternal than paternal non-transmitted risk alleles complemented the constellation to DQ2/DQ8 ( p<0.0099). HLA high risk alleles were more frequent among maternal non-inherited (but possibly exposed) alleles than among paternal non-inherited alleles. These results indicate that HLA DR-DQ is an environmental risk factor for Type I diabetes.

HLA-DQA1 and Polymarker Loci Allele Frequencies in the Bharias, a Primitive Indian Tribal Population from Patalkot, India

Abstract Twenty-three specimens were collected from unrelated volunteer blood donors. DNA was obtained from blood specimens using “QIAamp Blood and Tissue kit” (QIAGEN GmbH, Hilden, Germany) according to the manufacturer's recommended protocol. Amplification was carried out in a “Gene Amp® PCR system 2400” thermal cycler (Perkin Elmer Corporation, California) using 5 ng target DNA. Typing of the six loci was performed by reverse dot blot with Allele Specific Oligonucleotides (ASO) probes, using “AmpliType® PMHLADQA1 PCR amplification and typing kit” (Roche Molecular Systems, Inc., New Jersey).

Molecular properties of HLA-DQ alleles conferring susceptibility to or protection from insulin-dependent diabetes mellitus: keys to the fate of islet beta-cells.

The major histocompatibility complex Class II alleles, HLA-DQ, and the related HLA-DR, are the chief genetic elements of human type 1 diabetes. These genes code for polymorphic heterodimeric proteins, whose chief function is to trap peptide antigens in the endosome and present them on the surface of antigen-presenting cells (dendritic cells, B lymphocytes, monocytes/macrophages) to CD4(+) T helper cells. A systematic investigation of the molecular properties of HLA-DQ alleles linked to susceptibility or resistance to type 1 diabetes has shown that these properties segregate along lines of susceptibility or resistance. A correlation of these features with the function of each particular segment of the HLA-DQ molecule yields interesting insights into the possible pathways leading to type 1 diabetes. There remain, however, areas to be clarified, including mechanisms by which dominant protection is conferred by certain alleles, the interplay between HLA-DQ and the related locus HLA-DR, that also shows autoantigen-specific reactivity, and the cross-Class help delivered to CD8(+) T cells, the final effectors in pancreatic beta-cell destruction. Clarification of these issues may lead to ways to prevent diabetes in predisposed individuals already exhibiting the genetic and immunological characteristics, and perhaps a cure in those with the disease, by means of transplantation, and measures for prevention of disease recurrence.

A novel HLA‐DQA1 allele, DQA1*01042

We have identified a novel HLA-DQA1 allele in the homozygous cell line KGV (I HW9309) derived from a Caucasoid individual from the Indian subcontinent. This novel allele, DQA1*01042, differs from the DQA1*01041 allele by a single synonymous substituition within exon 3, position 438A-->C.1

Distribution of HLA-DQA1 and Amplitype PM Locus Alleles in Aegean Region of Turkey

Abstract The samples were collected from unrelated individuals randomly selected from criminal cases. The DNA was extracted from fresh blood leucocytes, bloodstains, and single hairs by Chelex 100 method (1).

Genetic admixture in three Mexican Mestizo populations based on D1S80 and HLA-DQA1 loci.

This study compares genetic polymorphisms at the D1S80 and HLA-DQA1 loci in three Mexican Mestizo populations from three large states (Nuevo León, Jalisco, and the Federal District). Allele frequency distributions are relatively homogenous in the three samples; only the Federal District population shows minor differences of the HLA-DQA1 allele frequencies compared with the other two. In terms of genetic composition, these Mestizo populations show evidence of admixture with predominantly Spanish-European (50-60%) and Amerindian (37-49%) contributions; the African contribution (1-3%) is minor. Together with the observation that in Nuevo León, the admixture estimates based on D1S80 and HLA-DQA1, are virtually the same as those reported earlier from blood group loci, suggests that DNA markers, such as D1S80 and HLA-DQA1 are useful for examining genetic homogeneity/heterogeneity across Mestizo populations of Mexico. The inverse relationship of the proportion of gene diversity due to population differences (Gst) to within population gene diversity (Hs) is also consistent with theoretical predictions, supporting the use of these markers for population genetics studies.

HLA-DQ and DRB1 polymorphism and susceptibility to type 1 diabetes in Jamaica.

Genetic susceptibility to type 1 diabetes is determined by a combination of HLA-DQ and DRB1 alleles. In the present study, HLA associations with type 1 diabetes were investigated in the Jamaican population. DRB1 and DQ genotyping was performed on 45 type 1 diabetic patients and 132 control subjects born and resident in Jamaica. The small number of patients available for study reflected the low prevalence of type 1 diabetes in Jamaica. The results were compared with those from other African heritage populations and white Caucasians. The highest relative risk was associated with the DRB1*03-DQ2/DRB1*04-DQ8 genotype. Both DRB1*0401-DQ8 and DRB1*0408-DQ8 were positively associated with disease. DRB1*0408-DQ8 is uncommon amongst white Caucasians, where DRB1*0401-DQ8 is the major predisposing haplotype. The DRB1*1503-DQ6 haplotype was associated with protection from diabetes in the Jamaican population. This haplotype is rare amongst white Caucasians, where DRB1*1501-DQ6 is the protective haplotype. Data from African heritage populations suggest that DRB1*1503-DQ6 might be less protective than DRB1*1501-DQ6. DRB1*03-DQA1*0401-DQB1*0402 was associated with protection from diabetes in the Jamaican population, whereas in white Caucasians DRB1*08-DQA1*0401-DQB1*0402 is predisposing. These data demonstrate that comparison of genetic associations with type 1 diabetes in races with population-specific DRB1-DQ haplotypes provides new information as to the exact determinants of disease susceptibility. Further support is provided for roles of the DQ genes and the DRB1 gene (or a gene in linkage disequilibrium with it) in determining susceptibility to type 1 diabetes.

In the European population HLA-class II genes are not associated with Helicobacter pylori infection.

Genetic variability influences susceptibility to several diseases and depends on the specific ethnic background of individuals. HLA-class II genes have repeatedly been investigated as candidate genes for predisposition to Helicobacter pylori infection. Certain HLA-DQA1 alleles have been reported to be associated with gastric and duodenal ulcer disease in infected patients in the Japanese population. But conflicting results were reported on European and Japanese populations. HLA-DRB1 typing of 382 German individuals with well-defined H. pylori status and different clinical course of the disease was performed by polymerase chain reaction and allele-specific oligonucleotide hybridization. No association with the infection status itself was observed in the German cohort. Similar results have been found in other European populations. In contrast, re-analysis of published data in a Japanese cohort revealed a highly significant association of DRB1*1501 with uninfected controls (P = 0.00035). In the German population, the carrier frequency of DRB1*15 was higher in H. pylori-positive individuals with gastric or duodenal ulcer but without statistical significance (gastric ulcer: odds ratio, 2.13; chi2 = 3.77; P = 0.05; Bonferroni correction, Pc = not significant; and duodenal ulcer: odds ratio, 2.15; chi2 = 3.4; P = 0.06; Pc = not significant). In infected individuals, autoantibodies to gastric mucosa were investigated, but no statistical significant difference in carrier frequencies of HLA-DRB1 alleles was evident. The DRB1*1501-DQA1*01021-DQB1*0602 haplotype seems to provide protection from H. pylori infection in the Japanese population, whereas genetic variability in HLA-class II genes has only a minor impact on H. pylori infection and its clinical course in the European population.

Myenteric antiplexus antibodies and class II HLA in achalasia.

Achalasia, a motor disorder of the esophagus, is accompanied by autoimmune phenomena that could be playing a role in the pathogenesis of the disease. Our objective was to establish the genotypic frequency of the HLA-DR and DQ alleles in patients with achalasia and to establish their relationship with the presence of myenteric antiplexus antibodies in our geographic area. A total of 92 patients diagnosed with achalasia and two control groups with 275 healthy subjects were studied for HLA typing and 40 for autoantibodies determination. The myenteric antiplexus antibodies were positive in 50 patients (54.3%) and in 3 healthy subjects (7.5%) (P < 0.001). The patients showed a significantly higher frequency of DQA1*0103 and DQB1*0603 than was found in the controls. The heterodimer DQA1*0103-DQB1*0603 was increased in the patients [odds ratio (OR) = 2.57]. In regard to the association between the HLA DQA1 and DQB1 alleles and the antiplexus antibodies, these antibodies were found in greater prevalence in those patients with the DQA1*0103 and DQB1*0603 alleles, and the differences were statistically significant (OR = 3.17 and OR = 5.82, respectively). All of the women and 66.7% of the men with achalasia and the DQB1*0603 allele or the DQA1*0103-DQB1*0603 heterodimer were positive for antibodies.

T cell response pattern to glutamic acid decarboxylase 65 (GAD65) peptides of newly diagnosed type 1 diabetic patients sharing susceptible HLA haplotypes.

Autoantibodies and autoreactive T lymphocytes directed against several pancreatic beta cell proteins such as GAD65 have been identified in the circulation before and at the onset of clinical type 1 (insulin-dependent) diabetes. Using GAD65 synthetic peptides, we studied the proliferative response of peripheral blood mononuclear cells (PBMC) either from recently diagnosed type 1 diabetic patients, of whom the majority share the disease-associated HLA class II haplotype (DR4-DQB1*0201 or DR3-DQB1*0302), or from HLA-matched control subjects. We found that 67% (14/21) of the type 1 diabetic patients and 39% (9/23) of the control subjects exhibited a positive proliferative response. Compared with control subjects, however, PBMC from diabetic patients proliferated more frequently (P < 0.05) in the presence of peptide pools from the C-terminal region of GAD65 (amino acids 379-585). Diabetic patients with the same HLA-DQ or HLA-DR alleles showed partially identical T cell reactivity, but no clear correlation could be made between MHC class II specificity and T cell epitopes because of multiple combinations of class II alleles. In addition, by flow cytometry, we studied the direct binding of GAD65 peptides to MHC class II molecules of Epstein-Barr virus (EBV)-transformed B (EBV-B) cells obtained from a diabetic patient. We found that 11 GAD peptides were able to bind to the highly susceptible haplotype DRB1*0301/0401-DQA1*0301/0501-DQB1*0302/0201 on the surface of EBV-B cells in partial correlation with the results obtained in the proliferation assays.

Modern concepts for the prediction of type 1 diabetes.

Type 1 diabetes results from the destruction of the insulin-producing beta cells of the pancreas. The disease process is thought to be initiated by a complex interaction between genetic and environmental factors leading to a cellular and humoral autoimmune response against beta cell specific components. Over the past decade there has been important progress in identification of several diabetes specific autoantigens. The availability of recombinant antigens, most notably the enzyme glutamic acid decarboxylase (GAD) and the tyrosine phosphatase-like molecule IA-2, made it possible to develop simple, sensitive and specific radioimmunoassays for the detection of autoantibodies on a large scale. It has been shown that the combination of GAD antibodies (GADA) and IA-2 antibodies (IA-2-A) with insulin autoantibodies (IAA) can replace the conventional ICA test. This considerably facilitates screening programmes. Prospective studies in subjects with and without family history of type 1 diabetes conclusively demonstrate that the risk for type 1 diabetes is strongly correlated with the number of positive antibodies. The 5-10-years risk for type 1 diabetes varies from 0-1% in individuals with only one positive antibodies to 62-100% in subjects who were positive for three or more antibodies. Despite the identification of novel genetic markers associated with type 1 diabetes, the major histocompatibility complex, namely HLA-DQ alleles, still represents the strongest genetic risk factor. The analysis of HLA-DQ alleles may be important to discriminate between subjects at high or intermediate risk from antibody positive individuals carrying protective haplotypes. Assessment of the metabolic state using the first phase insulin response to intravenous glucose may provide additional information to predict rapid progression to diabetes. Screening for multiple antibodies is the most specific and sensitive strategy for identifying subject at risk for type 1 diabetes. Second-line genotyping or analysis of the first phase insulin response can serve as useful tool to improve the prediction of type 1 diabetes. The value of additional markers such as isotype specific autoantibodies or T-helper cells subsets measured by ELISPOT assays or FACS remains to be shown.

Human leukocyte antigen-DQ and DR polymorphisms predict rheumatoid arthritis outcome better than DR alone

Conflicting data have been published on the value of the shared epitope (SE) hypothesis in predicting disease outcome in rheumatoid arthritis (RA). Recently we have proposed an alternative hypothesis, referred to as the RA protection (RAP) model. In this model, the HLA-DQ loci carry predisposition while HLA-DRB1 alleles encoding the motif DERAA provide protection against severe RA. In the present study, we have compared the respective values of the models in predicting both remission and erosions in early RA patients. We made use of an early arthritis clinic in which 158 RA patients and 138 patients with undifferentiated arthritis were enrolled. Patients were typed for HLA-DQ and -DR using high resolution DNA typing methods. Homozygosity for predisposing HLA-DQ alleles was associated with no remission and high erosion score. The presence of DERAA-bearing DRB1 alleles was negatively associated with erosions in otherwise predisposed individuals and increased the chance of being in remission. We found that the RAP model was significantly better than the SE model in predicting remission rate and erosion scores at one and two years in early RA patients. We conclude that HLA polymorphism does not only affect RA susceptibility, but also protects against severe disease at early stage.

Major histocompatibility locus genetic markers of beryllium sensitization and disease.

Hypersensitivity to beryllium (Be) is found in 1-16% of exposed workers undergoing immunological screening for beryllium disease using the beryllium lymphocyte proliferation test (BeLPT). However, only approximately 50% of BeLPT-positive workers present with lung granulomas (i.e. berylliosis). As berylliosis is associated with the human leukocyte antigen (HLA)-DP supratypic marker DPGlu69, the authors asked whether this marker is differentially associated with disease presentation. A population of 639 workers from a beryllium factory undergoing BeLPT screening was evaluated in a nested case-control study for the prevalence of HLA-DPGlu69, the HLA-DPB1, HLA-DQ and HLA-DR alleles and of the biallelic tumour necrosis factor (TNF)-alpha polymorphism TNF-alpha-308 in 23 individuals presenting as "sensitized" (i.e. BeLPT-positive without lung granulomas) and in 22 presenting as "diseased" (i.e. BeLPT-positive with granulomas in the lung biopsy). The HLA-DPGlu69 marker was associated with "disease" (odds ratio (OR) 3.7, p=0.016, 95% confidence interval (CI) 1.4-10.0), whilst the high TNF-alpha production-related TNF-alpha-308*2 marker was associated with both a positive BeLPT (OR 7.8, corrected p<0.0001, 95% CI 3.2-19.1) with no difference between "sensitization" and "disease". Furthermore, the HLA-DRArg74 marker was associated with "sensitization" without disease (OR 3.96, p=0.005, 95%, CI 1.5-10.1). The data indicate that tumour necrosis factor-alpha, human leukocyte antigen-DR and human leukocyte antigen-DP markers play different roles in beryllium sensitization and granuloma formation in beryllium-exposed workers.

Distribution of HLA-DQA1 and Amplitype PM Locus Alleles in a Turkish Population Sample

Abstract The samples were collected from unrelated individuals randomly selected from criminal cases. The DNA was extracted from fresh blood leucocytes, bloodstains, and single hairs by Chelex 100 method (1).

HLA-DQA1 allele typing by nonisotopic PCR-LIS-SSCP.

In the present study we used a simple and reliable method for HLA-DQA1 allele typing based on the single-stranded conformation polymorphism (SSCP) properties of DNA molecules obtained by PCR. The technique consists of PCR amplification of a DNA fragment comprising the second exon of the HLA-DQA1 gene, amplicon denaturation using a low ionic strength solution (LIS), and electrophoresis on a small native polyacrylamide gel, followed by a rapid silver staining procedure. In order to validate the technique and to obtain the allele patterns for the DQA1 gene, 50 cervical samples were typed using this methodology and the commercial Amplitype HLA DQA1 Amplification and Typing kit. All the alleles detected with the kit were characterized by the LIS-SSCP approach. This procedure proved to be useful for population screening and typing of the DQA1 gene as well as for detecting new alleles or mutations in the donor-recipient molecular matching of HLA class II genes.

Accuracy and cost-effectiveness of a new strategy to screen for celiac disease in children with Down syndrome

Objectives: To investigate the best approach to screen for celiac disease (CD) in patients with Down syndrome (DS). Study design: One hundred thirty-seven children with DS were followed up longitudinally. CD screening was offered in 1994, 1996, and 1999 by determination of serum immunoglobulin A–anti-endomysium antibodies (AEA). The HLA-DQA1*0501/DQB1*02 allelic combination known to be strongly positively associated with CD was typed. All IgA-AEA–positive children were given the opportunity to undergo a small bowel biopsy: if villous atrophy was found, the diagnosis of CD was established. Results: CD was diagnosed in 11 (8%) children: 8 in 1994 and 3 in 1996. All of them carried the HLA-DQ alleles associated with CD. The presence of symptoms was not useful in discriminating which children could have CD. Conclusions: Screening once in a lifetime is not enough to detect CD in patients with DS. We propose a new, accurate, and cost-sparing 2-step strategy for screening, based on selection of the individuals with potential CD by HLA-DQ typing and on longitudinal serologic CD screening in this selected group. (J Pediatr 2000;137:756-61)

Analysis of the CDKN2A and CDK4 genes and HLA-DR and HLA-DQ alleles in two Spanish familial melanoma kindreds.

Some confusion exists in the literature about which criteria should be used to define familial melanoma. This could explain the different reported frequencies of mutations in predisposing genes, mostly CDKN2A, in these patients. This study evaluated the human leucocyte antigen (HLA) class II genotype and the presence of mutations in CDKN2A and CDK4 genes in 2 families with very different clinical features. The family with a germinal mutation in exon 2 of CDKN2A (Gly101Try) presented the following clinical features: 3 first-degree affected members, 1 of whom had 2 melanomas, and all the melanomas appearing before 35 years of age. In contrast, the second family did not present any mutation in the studied genes and included 2 first-degree affected members diagnosed at over 45 years of age. Neither family showed an association with HLA genotype. Other genes are also involved in familial melanoma but, when the CDKN2A gene is affected, some clinical features seem to be uniform.

Distribution of HLA-DQA1, Polymarker, CSF1PO, vWA, TH01, TPOX, D16S539, D7S820, D13S317, and D5S818 Alleles in East Bengali and West Punjabi Populations from Indo-Pak Subcontinent

Blood samples were collected from 115 individuals residing in the Pakistani state of West Punjab and 81 Bengali individuals residing in the state of East Bengal, India. These samples were analyzed for the loci HLA-DQA1, PM (LDLR, GYPA, HBGG, D7S8, and GC) and eight short tandem repeats: CSF1PO, TPOX, THO1, vWA, D16S539, D7S820, D13S317, and D5S818. Departures from Hardy-Weinberg (HWE) were observed in Punjabi population at LDLR, THO1, D13S317, D5S818, and D16S539 and at CSF1PO and THO1 in Bengali population.