DIVERSITY OF HLA-B15 IN KOREANS.
KW Lee, HB Chyun, JS Lee, JY Park, HC Cho, Department of Clinical Pathology, College of Medicine, Hallym University, Seoul, Korea.
Alleles in HLA-B15 group (B*1501-B*1538) encode molecules belonging to seven serologic subgroups, B62, B63, B71, B72, B75, B76, and B77, and have known to be one of the most problematic types to assign in routine clinical typing laboratories due to their serologic cross-reactivity resulting from structural similarity. Although more than 25% of Koreans express HLA-B molecules derived from HLA-B15 alleles, this allele family has not been well studied in the population. To characterize HLA-B15 in this population, B15 specific PCR and SSOP hybridization analysis using 39 digoxigenin-labeled probes were applied to DNA samples obtained from 245 B15 serologic positive unrelated individuals. Among the 38 HLA-B15 alleles, nine different alleles were identified and B*1501 is the highest (66.9%) followed by B*1511 (14.7%), B*1507 (10.2%), and B*1518 (5.7%) comprising more than 95% of B15 positive samples. The B62 appeared to be most polymorphic consisting of 5 different alleles (B*1501, B*1507, B*1525, B*1527, and B*1538) and four of them could not be discriminated by serologic reaction patterns. Among the fifteen B62 homozygous samples, eight appeared to be B15 heterozygous carrying either B*1507 (B62) or B*1518 (B71) as a second hidden allele. In addition, several B*15 alleles exhibit strong associations with a specific Cw and/or DRB1 allelic types (e.g., B*1507-Cw3 (25/25); B*1507-DRB1*04 (23/25)). These data will be helpful in accurate assignment of HLA-B15 related types by serology as well as in determining the strategy for establishing DNA typing for this population.