HLA A*02 allele frequencies and B haplotype associations in Western Indians.

The population of Western India is described as Australoid or Proto-Australoid elements with admixture from Caucasian, Mongoloid, and Aryan races. We investigated the frequencies of human leukocyte antigen (HLA) A*02 alleles and their B* allele haplotype associations among 664 healthy unrelated Western Indians. Fifty-one of 204 serologically typed A2 individuals were analyzed for 56 molecular A*02 subtypes using high resolution polymerase chain reaction-reverse line strip-sequence-specific oligonucleotide hybridization (PCR-RLS-SSOP). A total of seven different A*02 alleles were identified, A*02011 (16%), A*0203 (16%), A*0205 (2%), A*0206 (2%), A*0211 (52.9%), A*0222 (4%), and A*0236 (8%). The most common HLA B allele associated with A*02 was B*40. Among the 42 subtypes HLA B*4006 (37.22%) was the most frequent subtype. HLA A*0211 was highly frequent in this population, A*0206 and A*0203 are common alleles observed among Asian populations, whereas A*0205 occurs in Caucasians and Africans and A*0222 has been observed among Hispanics. A*0236 has been observed among the western Indians exclusively. Most of the HLA A*02 subtypes observed were associated with B*4006 haplotype, although A*0236 was with B*0702 or B*1302 among the western Indians. The prevalence of A*0211 at high frequencies, A*0222, A*0236 novel alleles along with A*02 related haplotypes, demonstrate a substantial heterogeneity, which may be a consequence of founder effect, racial admixture, or selection pressure due to environmental factors.