Molecular diversity of HLA-A, -B and -C alleles in a North Indian population as determined by PCR-SSOP.

We have used molecular methods to determine the frequencies of human leukocyte antigen (HLA)-A, -B and -C alleles in normal, healthy, unrelated individuals from North India using polymerase chain reaction and hybridization with sequence-specific oligonucleotide probes as there is no comprehensive report showing molecular diversity of all the class-I alleles present in North Indians. A0101, A0206, A0301, A1101, A6801, A2401 and A3101 were the most prevalent alleles of the A locus with 91.11% of the samples showing heterozygosity. At the HLA-B locus a total of 47 B locus alleles were observed and the only allele found with an allele frequency of 15% was B5801. Other frequent B-locus alleles observed were B5101, B3503 and B4006 with relatively less frequent alleles like B5201, B3501, B0702, B4403, B5701, B1801 and B5501. Of the samples studied 92.31% were heterozygous for B-locus alleles. Cw0602 and Cw0401 were the most frequent C-locus alleles. Other frequent C-locus alleles were Cw0102, Cw0302, Cw0701, Cw0702, Cw1202, Cw1203, Cw1502 and Cw1503. HLA alleles common in Africans like B5801, A68012, B5301, B44032, B4006 and Cw1701 were observed in the North Indians besides oriental alleles like B1301, B1502 and B4001 confirming that the genetic make-up of North Indians is Caucasoid with elements of Mongoloid and Negrito races. Some new/rare alleles like B1802, described as a new allele from Thailand and B*8101, described earlier in a Bubi population were also observed although with low frequencies, showing the diversity of HLA class-I alleles present in the North Indians.