HLA-B*15 diversity in Sichuan Han population

Objective To investigate the allele distribution of HLA-B*15 gene family in Sichuan Han population.Methods A total of 107 B*15-positive samples were selected from 8934 Sichuan Han individuals from Sichuan Umbilical Cord Blood Bank(CMDP),based on their HLA-B types determined by PCR-SSP or PCR-SSO using commercial typing kits.PCR-SBT was applied to determine HLA-B*15 allele typing.Allele frequencies were analyzed by square root method.And the chi-square values of allele frequencies from different populations were also analyzed.Results A total of 16 different HLA-B*15 alleles and a novel or unknown HLA-B*15 allele were identified.B*1502(36.2%) was the most frequent allele,followed by B*15010101(21.6%),B*151101(9.5%),B*1518(6.9%),B*1525(6.0%),which comprised more than 80% of all the B*15-positive samples.In the B62 serologic group,seven alleles were identified,including B*15010101,B*1505,B*1507,B*1525,B*1527,B*1532,B*1558.In the B75 serologic group,B*1502 and B*151101 were identified in the study samples and B*1502 was predominant.In addition,there was a novel or unknown HLA-B*15 or B*46 in our study.Its sequence differed from all known HLA-B*15 or B*46 allele sequences by a single 116 C-T substitution in exon 3.Further research is required to identify this unknown allele.Conclusion Our study demonstrates the high diversity of B*15 in the Sichuan Han population.