HLA-B*15 diversity in the Korean population.

Alleles in the HLA-B15 group encode molecules belonging to several serologic subgroups, B15 (B62, B63, B75, B76, B77) and B70 (B71, B72), representing many of the most problematic types to assign in routine clinical typing laboratories due to their serologic cross-reactivity resulting from structural similarity. More than 25% of Koreans express HLA-B molecules encoded by the HLA-B15 alleles. To further characterize HLA-B15 in this population, B15-specific polymerase chain reaction (PCR) and sequence-specific oligonucleotide probe (SSOP) hybridization analysis using 39 digoxigenin-labeled probes were applied to DNA samples obtained from 237 B15/B70 serologically positive unrelated individuals. Nine B15 alleles were identified. B1501 was the most frequent allele (64.8%) followed by B1511 (14.1%), B1507 (8.6%), and B1518 (5.5%) comprising more than 90% of B15-positive samples. B62 molecules encoded by 4 of the identified alleles (B1501, B1507, B1525, and B1527) could not be discriminated by serologic reaction patterns. Among the fifteen B15/B70 apparent homozygotes, eight were heterozygotes carrying two different B15 alleles. Several B15 alleles exhibited strong associations with specific Cw, DRB1, and A allelic types (e.g., B1507-Cw3 (22/22); B1507-DRB104 (21/22), B1507-A24 (17/22)). The data obtained in this study confirmed B*15 diversity in the study population and will be useful in hematopoietic stem cell donor searches as well as in determining the supplementary DNA typing strategy for B15/B70-positive samples in this population.