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. A*0101, A*0206, A*0301, A*1101, A*6801, A*2401 and A*3101 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 B*5801. Other frequent B-locus alleles observed were B*5101, B*3503 and B*4006 with relatively less frequent alleles like B*5201, B*3501, B*0702, B*4403, B*5701, B*1801 and B*5501. Of the samples studied 92.31% were heterozygous for B-locus alleles. Cw*0602 and Cw*0401 were the most frequent C-locus alleles. Other frequent C-locus alleles were Cw*0102, Cw*0302, Cw*0701, Cw*0702, Cw*1202, Cw*1203, Cw*1502 and Cw*1503. HLA alleles common in Africans like B*5801, A*68012, B*5301, B*44032, B*4006 and Cw*1701 were observed in the North Indians besides oriental alleles like B*1301, B*1502 and B*4001 confirming that the genetic make-up of North Indians is Caucasoid with elements of Mongoloid and Negrito races. Some new/rare alleles like B*1802, 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.