HLA-DRB, -DQA, and DQB alleles and haplotypes in Iranian patients with diabetes mellitus type I

Distribution of HLA-DQA1, -DQB1 and -DRB1 genes and haplotypes in Han, Uyghur, Kazakh and Hui populations inhabiting Xinjiang Uyghur Autonomous Region, China

Genetic polymorphisms of human leucocyte antigen (HLA)-DRB1, -DQA1 and -DQB1 among four main ethnic groups including Han (n = 70), Uyghur (n = 71), Kazakh (n = 52) and Hui (n = 40) subjects from Xinjiang Uyghur Autonomous Region were investigated using a polymerase chain reaction-sequence-based typing (PCR-SBT). In total, 32 HLA-DRB1 alleles, eight HLA-DQA1 alleles and 14 HLA-DQB1 alleles were identified. The most predominant HLA-DRB1, -DQA1 and -DQB1 alleles were DRB1*15:01 (12.50%), DQA1*01:02 (21.43%) and DQB1*03:01 (19.29%) in Han; DRB1*07:01 (18.48%), DQA1*05:01/03/05 (24.65%) and DQB1*02:01/02 (31.69%) in Uyghur; and DRB1*13:01 (13.64%), DQA1*05:01/03/05 (28.85%) and DQB1*02:01/02 (27.88%) in Kazakh, respectively. In Hui, DRB1*07:01, DRB1*11:01 and DRB1*14:01 were the most dominant alleles with the same frequency of 11.8%, while the predominant DQA1 and DQB1 alleles were DQA1*03:01/02/03 (23.75%) and DQB1*02:01/02 (16.25%), respectively. In addition, the most common two-locus haplotypes were DQA1*05:01/03/5-DQB1*03:01 (10.0%) in Han; DQA1*02:01-DQB1*02:01/02 (18.31%) in Uyghur; DQA1*05:01/03/05-DQB1*02:01/02 (15.38%) in Kazakh; and DQA1*03:01/02/03-DQB1*03:03 (11.25%) in Hui. The phylogenetic dendrograms constructed based on the allele frequencies of HLA-DRB1, -DQA1 and -DQB1 in 13 populations (e.g. Asian, Central Asian and European) revealed that the Han and Hui populations were clustered together and closest to Han population from China, while the Kazakh and Uyghur populations were closest to each other and two ethnic groups were clustered together with Central Asian and European populations.

HLA Allele and Haplotype Frequencies in Three Urban Mexican Populations: Genetic Diversity for the Approach of Genomic Medicine

Genetic variability defends us against pathogen-driven antigens; human leucocyte antigens (HLA) is the immunological system in charge of this work. The Mexican mestizo population arises mainly from the mixture of three founder populations; Amerindian, Spaniards, and a smaller proportion of the African population. We describe allele and haplotype frequencies of HLA class I (-A and -B) and class II (-DRB1 and -DQB1), which were analyzed by PCR-SSP in Mexican mestizo from three urban populations of Mexico: Chihuahua-Chihuahua City (n = 88), Mexico City-Tlalpan (n = 330), and Veracruz-Xalapa (n = 84). The variability of the allele HLA class I and class II among the three regions of Mexico are in four alleles: HLA-A*24:02 (36.39%), -B*35:01 (16.04%), -DRB1*04:07 (17.33%), and -DQB1*03:02 (31.47%), these alleles have been previously described in some indigenous populations. We identified 5 haplotypes with a frequency >1%: HLA-A*02:01-B*35:01-DRB1*08:02-DQB1*04:02, A*68:01-B*39:01-DRB1*08:02-DQB1*04:02, A*02:01-B*35:01-DRB1*04:07-DQB1*03:02, A*68:01-B*39:01-DRB1*04:07-DQB1*03:02, and A*01:01-B*08:01-DRB1*03:01-DQB1*02:01. Also, the haplotype A*02:01-B*35:01-DRB1*08:02-DQB1*04:02 was identified in Tlalpan and Xalapa regions. Haplotype A*01:01-B*08:01-DRB1*03:01-DQB1*02:01 was found only in Tlalpan and Chihuahua. In the Xalapa region, the most frequent haplotype was A*24:02-B*35:01-DRB1*04:07-DQB1*03:02. These alleles and haplotypes have been described in Amerindian populations. Our data are consistent with previous studies and contribute to the analysis of the variability in the Mexican population.

Alteration in CD8+ T cell subsets in enterovirus-infected patients: An alarming factor for type 1 diabetes mellitus

Type 1 diabetes is a multi-factorial disease that can develop due to the combination of genetic and environmental factors. Viruses, particularly enteroviruses, are major environmental candidates in the pathogenesis of type 1 diabetes, even though the mechanisms of pathogenicity of these viruses and their effects on the immune system have not been understood very well yet. Previous studies show that any imbalance in the population of different lymphocyte subsets could develop autoimmune diseases. Our theory is that enteroviral infection causes an impairment in the distribution of lymphocyte subtypes and consequently results in the diabetes onset in some individuals. Therefore, in this project, we evaluated the distribution of T CD8+ lymphocytes and their subsets in type 1 diabetes patients. This study was conducted to investigate the relationship between enteroviral infection and type 1 diabetes mellitus in an Iranian population, and suggestion a predicting approach for susceptible subjects.

Effect of swine leukocyte antigen-DQA gene variation on diarrhea in Large White, Landrace, and Duroc piglets

Piglet diarrhea is one of the most common factors that affects the benefits of the swine industry. Although recent studies have shown that exon 2 of SLA-DQA is associated with piglet resistance to diarrhea, contributions of genetic variation in the additional exon coding regions of this gene remain unclear. Here, we investigated variation in exons 1, 3 and 4 of the SLA-DQA gene and evaluated their effects on diarrheal infection in 425 suckling piglets. No variation was identified in exon 1. In exon 3, there were eight alleles detected, generated by 14 single nucleotide polymorphisms (SNPs) and three nucleotide deletions, eight SNPs being newly identified. Four allele sequences and three SNPs were identified in exon 4, only one SNP being newly identified. Statistical analysis showed that the genotypes of exon 3 are significantly associated with piglet diarrhea; indeed, genotypes DQA*wb01/wb02 and wb04/wb05 are clearly associated with resistance to piglet diarrhea, as they have the lowest probabilities of infection (P < 0.05). However, no significant association was found between the genotypes of exon 4 and diarrhea (P > 0.05). These results provide important new information concerning the level of genetic diversity at the SLA-DQA locus and suggest that further genetic association studies of piglet diarrhea resistance should include analyses of both exons 2 and 3 of this locus.

Association of HLA-DQA1 and -DQB1 alleles with type I diabetes in Arabs: a meta-analyses

This study aimed at assessing the nature and significance of associations between various alleles of HLA-DQA1, HLA-DQB1, and type I diabetes (T1D) in Arab populations. Evidence from literature (published before 20 April 2015) was amassed and analysed through multiple meta-analyses, which yielded effect summary odds ratios and 95% confidence intervals for 24 alleles and 4 haplotypes. A total of 1273 cases and 1747 controls from 16 studies were analysed. High levels of significance were obtained to support higher T1D risk when harbouring DQA1*03:01. The alleles DQB1*02:01 and *03:02 and the haplotypes DR3 and DR4 were significant risk factors, albeit with high publication heterogeneity. The protective effects of DQA1*01:01, DQB1*05:03, *06:02, *06:03, and *06:04 were robustly suggested by all indicators of meta-analyses. The haplotypes DR7 and DR11 were strongly suggested to be protective in Arabs. A relatively small number of studies have emerged from Arab countries, mostly with inadequate power on an individual basis. This study fills the gap by providing significant size effect of human leukocyte antigen (HLA) alleles and completes the continuum of global ethnic differences in this context.

Evaluation of Association Between HLA Class II DR4-DQ8 Haplotype and Type I Diabetes Mellitus in Children of East Azerbaijan State of Iran

PURPOSE

Association between HLA-DR4-DQ8 haplotype and type 1 Diabetes Mellitus (DM-1A) was investigated in children of East Azerbaijan state of Iran because such an association has not been previously studied in this population.

METHODS

HLA-typing was performed by polymerase chain reaction sequence-specific priming. For haplotype analysis, the logistic regression model was performed.

RESULTS

Of the three investigated alleles, the frequency of DRB1*0401 was significantly higher among patients compared with that in healthy subjects (76.74% vs. 23.26%).

CONCLUSION

The findings of the current study are consistent with those of previous studies and show that DRB1*0401 is associated with DM-1A; the frequencies of the two other alleles were also higher among patients, although the differences were not statistically significant. Two haplotypes associated with these alleles were also surveyed, and DRB1*0401--DQA1*0301-, and DRB1*0401--DQA1*0301--DQB1*0302- were the most frequent haplotypes among the patient group.

Association between polymorphisms of the swine MHC-DQA gene and diarrhoea in three Chinese native piglets

Swine leucocyte antigen (SLA) is a highly polymorphic multigene family that plays a crucial role in swine immune response and disease resistance. Here, we identified polymorphisms and gene variations of SLA-DQA exon 2 using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing analysis, and further investigated the correlation between the polymorphisms and piglet diarrhoea in three Chinese native pig breeds (Bamei, Juema and Gansu Black pigs). Consequently, 12 genotypes and 8 alleles including two novel alleles were detected. Nucleotide polymorphism was compared with the actual functional polymorphism in the peptide-binding region (PBR), binding pockets P1, P6 and P9, and the antigen-binding groove, variations in the antigen-binding groove of alleles DQA*01xa01, DQA*01xa03, DQA*01xb01, DQA*We02, DQA*03xb03 and DQA*wy06 were higher than alleles DQA*03xa01 and DQA*03xa03, while amino acid variations in peptide-binding pockets of allele DQA*03xa03 were most abundant among all alleles. The results of association analysis showed the diarrhoea score of Gansu Black pigs (-0.08 ± 0.78) was significantly higher than Bamei and Juema pigs (P < 0.01), and genotype DQA*03xa0103xa01 (0.39 ± 0.54) was significantly higher relative to other genotypes (P < 0.01), while that of genotype DQA*03xa0303xa03 (-1.31 ± 0.88) was markedly lower than scores obtained with genotypes DQA*03xa0103xa01 and DQA*03xa0101xa01 (P < 0.01), as well as DQA*01xa0101xa01 (P < 0.05), indicating that amino acid variations in the peptide-binding pockets play a more important role than the antigen-binding groove in piglet diarrhoea resistance. Further studies on other SLA molecules of native pigs are required to validate the link between this gene complex and diarrhoea.