Limited diversity of HLA-DRB1*02 alleles and DRB1-DRB5 haplotype associations in four United States population groups

At least 60 DRB1*02 positive individuals from each of four US population groups found within a hematopoietic stem cell volunteer donor registry – Caucasoids, African Americans, Asians/Pacific Islanders, and Hispanics – were randomly selected from a database of 82,979 individuals. DRB1*02 alleles were identified by DNA sequencing. A total of five of 23 known DRB1*02 alleles were detected. DRB1*15011 was the predominant DRB1*02 allele in Caucasoids and Hispanics. The most common DRB1*02 allele observed in African Americans was DRB1*1503, and DRB1*15021 in Asians/Pacific Islanders. Caucasoids were found to be the least diversified; only DRB1*15011 and DRB1*16011 were observed. A subset of individuals was also typed for DRB5 alleles by DNA sequencing. DRB5*01011, DRB5*0102, DRB5*0103, DRB5*0108N and DRB5*0202 were detected and nine DRB1-DRB5 haplotypes defined.