ASIAN INDIAN HLA-DR2-RELATED, DR4-RELATED, AND DR52-RELATED DR-DQ GENOTYPES ANALYZED BY POLYMERASE CHAIN-REACTION BASED NONRADIOACTIVE OLIGONUCLEOTIDE TYPING - UNIQUE HAPLOTYPES AND A NOVEL DR4 SUBTYPE

We have employed a PCR-based nonradioactive technique using biotinylat ed SSOPs to define HLA-DR2-, 4-, DR51-, and DR52-associated DR-DQ geno types in Asian Indian families. In the DR2 group, most haplotypes desc ribed by us in a previous study were confirmed by family analysis. Evi dence for one additional haplotype was available in this study. The cl assic DRB11501- and DRB1*1502-associated caucasoid haplotypes occurre d with an appreciable frequency in Asian Indians, but two of the DRB1 1601-associated Caucasoid haplotypes were absent. At least six unique and unusual DR2-associated genotypes were encountered. In the DR52 gro up, the three most common alleles are DRB10301, DRB1*1404, and DRB1*1 101. The DR6-associated alleles were DRB11301, 1302, 1401, and 1404. A few unique haplotypes occurred with low frequency in this group. In the DR4 group, at least three unusual patterns of hybridization were n oticed by family analysis. One of these appears to be a novel DR4 subt ype upon sequencing. These results demonstrate that, besides HLA-DR2, appreciable complexity occurs in the DR4- and DR52-associated alleles among Asian Indians. The presence of unique DR-DQ haplotypes in additi on to those found characteristically among Western Caucasians suggests that the Indian population provides valuable source of many HLA class II haplotypes.