Frequencies of HLA-A, B and DRB1 alleles in a large normal population living in the city of Mashhad, Northeastern Iran

Objective(s): The population in Iran is a genetic admixture of the ancestral Aryan and other populations neighboring Iran. Different ethnic groups in Iran show wide regional distributions for many human leukocyte antigen (HLA) alleles. Therefore, it is necessary and sensible to study the differences in HLA allele distribution in different area. We studied the HLA class I and II allele frequencies in a large unrelated healthy Iranian population from Mashhad in the Northeast region. Materials and Methods: Five hundred unrelated healthy adult individuals borne and living in Mashhad, Northeast of Iran, were genotyped for HLA-A, B and HLA-DRB1 alleles using PCR with low resolution sequence specific primers (SSP-PCR) technique. Results: A total of 14 HLA-A, 24 HLA-B and 10 HLA-DRB1 alleles were spread throughout the studied population with distinct allele frequencies. At the HLA-A locus, HLA-A*02 was found to be the most frequent allele, with a frequency of 20.9%. The most common HLA-B alleles was B*35 (16.4%). The two most common observed alleles in HLA class II alleles were DRB1*15 (20.0%) followed by DRB1*13 (16.2%). Conclusion: This study is the first on the HLA class I and II allele frequencies in Northeastern Iranian population living in Mashhad. Distribution of HLA-A and B loci showed some similarities with those of other Iranians. Some difference in HLA-DRB1 polymorphisms however was observed. Considering the highly mixed population of Mashhad, the finding was not unexpected.