Distributions of HLA‐DRB1/DQB1 alleles and haplotypes in the North‐eastern Thai population: indicative of a distinct Thai population with Chinese admixtures in the Central Thais

Abstract

The phenotype and gene frequencies of HLA class II alleles were studied in the North‐eastern Thai population. Blood samples were collected from 100 unrelated healthy North‐eastern Thais. The HLA‐DRB1 and DQB1 genes were typed using the polymerase chain reaction – sequence specific primer (PCR‐SSP) and polymerase chain reaction – sequence specific oligonucleotide probe (PCR‐SSO) techniques. Twenty‐six HLA‐DRB1 and 11 DQB1 alleles were found in this population. DRB1*1202, 1502, 0405 and DQB1*0502/0504, 0301/0304 alleles were commonly found. Linkage disequilibrium analysis suggested the existence of 13 DR‐DQ haplotypes. The DRB1*1502‐DQB1*0501 haplotype was the most common. The DRB1*1106‐DQB1*0301/0304 haplotype was found only in North‐eastern Thais and not in other Thai populations. Comparative analysis of the HLA‐DR/DQ alleles revealed differences in the distributions of these alleles amongst different ethnic groups. Interestingly, the distributions of HLA class II alleles in Central Thai, North‐eastern Thai and Southern Chinese populations are similar. However, it appears that the distribution in the Central Thais is a mixture of those in Southern Chinese and North‐eastern Thais, suggesting the existence of Thai–Chinese admixtures in the Central Thai population. This study provides basic information for further studies of the MHC in anthropology, organ transplantation and disease susceptibility in the North‐eastern Thai population.