Human Leukocyte Antigen (HLA) Class I and II Polymorphism in Iranian Healthy Population from Yazd Province

The major histocompatibility complex (MHC) genes are the most polymorphic loci in the human genome and have been widely studied in various populations and ethnic groups. Investigations into the HLA genes and proteins have been useful tool for anthropological, transplantation and disease association studies. The polymorphism of the HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1) genes were investigated in 90 unrelated Iranian individuals from Yazd province located in the center of Iran using sequence-specific primers (PCR-SSP). Allele and haplotype frequencies, expected/observed heterozygosity, unbiased expected heterozygosity, number of effective alleles, deviations from Hardy-Weinberg (HW) equilibrium and genetic diversity were computed. A total of 23, 48, 23, 24, 13 and 16 alleles for HLA-A, -B,-C, -DRB1, -DQA and -DQB loci were determined, respectively in the population study. The most frequent allele identified in this study were A*02:01 (18.889%), HLA-B* 51:01 (12.778%), HLA-C* 12:03 (17.033%), HLA-DRB* 11 (24.4%), HLA-DQA* 05:05 (20.55%) and HLA-DQB*03:01 (22.8%).Furthermore, the most frequent 3-locus haplotypes were DRB*11-DQA*05:01-DQB*03:01 (21.1%), HLA-A*02:01- B *50:01- DRB*07:01 (4.9%) and A*26:01 –B* 38:01 –C*12:03(5%). The most 4-locus haplotype were A*11:01 –B* 52:01 –C*12:03 –DRB!*15(2.5%) and A*02:01 –B* 50:01 –DRB1*07:01 –DQB1*02:01(4.5%). The heterozygosity of the study population was confirmed the expected value and not deviated from Hardy-Weinberg equilibrium for all loci (p>0.05). Our study shows a close relatedness between Yazd population and other ethnic group of Iran despite some differences, which may be due to admixture of each one of these groups with each other or foreigner subpopulations during centuries. Moreover, the results of this study suggest that the Iranian population from Yazd province is in close vicinity with the Caucasians populations and far from the Korean and Japanese populations.