Striking conservation of three extended HLA-DR13 haplotypes in the Japanese population.

HLA class II DNA typing was conducted for 1335 unrelated Japanese individuals. The study on the linkage disequilibrium revealed a striking conservation of HLA DR13 haplotypes. Among these Japanese, 155 were typed for HLA-DR13 serologically, and they were correspondent to three DRB1 alleles, DRB11301, 1302 and 1307 defined by using the polymerase-chain reaction and sequence-specific oligonucleotide probe (PCR-SSOP) method. The two alleles, DRB11301 and 1307 were exclusively associated with each specific DRB3-DQA1-DQB1 combination which was DRB11301-DRB30101-DQA10103-DQB10603, and DRB11307-DRB30202-DQA10501-DQB10301, respectively. DRB11302, the most common DR13 allele in Japanese, had two significant associations with DRB30301-DQA10102-DQB10604 (DRB11302A) and with DRB30301-DQA10102-DQB10605 (DRB11302B). In this study, no other DR13 class II combinations were found. Only the DRB11302A halotype was associated with the DPB10401 allele while the DRB11302B haplotype was not. The complete conservation of these DR13 class II haplotypes was found to extend toward the HLA class I region. They were HLA A3-B44-DRB11301, A33-B44-DRB11302A and A33-B17-DRB1*1302B. Japanese could be characterized with these three extended haplotypes which were remarkably different from those in Caucasian, Black and Asian other than Korean populations.