HLA-B*15 diversity in the Korean population

Area of Science:

• Immunogenetics
• Human Leukocyte Antigen (HLA) complex
• Population genetics

Background:

• HLA-B*15 alleles present challenges in routine clinical typing due to serologic cross-reactivity.
• Over 25% of Koreans express HLA-B molecules encoded by HLA-B*15 alleles, necessitating further characterization.

Purpose of the Study:

• To characterize the diversity of HLA-B*15 alleles in a Korean population.
• To identify specific HLA-B*15 alleles and their frequencies.
• To investigate associations between HLA-B*15 alleles and other HLA loci.

Main Methods:

• Utilized B*15-specific polymerase chain reaction (PCR) and sequence-specific oligonucleotide probe (SSOP) hybridization.
• Analyzed DNA samples from 237 serologically B15/B70 positive Korean individuals.
• Employed 39 digoxigenin-labeled probes for precise allele identification.

Main Results:

• Identified nine distinct HLA-B*15 alleles, with B*1501 (64.8%), B*1511 (14.1%), B*1507 (8.6%), and B*1518 (5.5%) being the most frequent.
• Discovered that B62 molecules, encoded by four alleles, could not be differentiated by serologic methods.
• Revealed that eight of fifteen apparent B15/B70 homozygotes were actually heterozygotes for different B*15 alleles.
• Observed strong associations between specific B*15 alleles and HLA-Cw, DRB1, and A types (e.g., B*1507-Cw3, B*1507-DRB1*04, B*1507-A24).

Conclusions:

• Confirmed significant HLA-B*15 allele diversity within the Korean population.
• Highlighted the limitations of serologic typing for certain HLA-B*15 alleles.
• Emphasized the utility of these findings for optimizing hematopoietic stem cell donor searches and DNA typing strategies in this population.