Relative HLA-DRB1*04 allele frequencies in five United States populations found in a hematopoietic stem cell volunteer donor registry and seven new DRB1*04 alleles.

The frequencies of 29 HLA-DRB104 alleles were determined for five major U.S. populations found within a hematopoietic stem cell volunteer donor registry. One hundred sixty-one DRB104 positive individuals from each of the self-described groups, Caucasians, African-Americans, Asian/Pacific Islanders, Hispanics, and Native Americans, were randomly chosen from a database of 82,979 unrelated persons. Subjected to polymerase chain reaction-sequence-specific oligonucleotide probe (PCR-SSOP) typing, these 805 individuals carried a total of ten different DRB104 alleles, ranging from DRB10401 to DRB10411 with DRB10409 conspicuously absent from all five groups. The distribution of DRB104 alleles varied among the groups, with DRB10401 being predominant in Caucasians, African-Americans, and Native Americans. DRB10404 and DRB10407 were the two most commonly observed alleles in Hispanics, whereas DRB10405 and DRB104031 were most common in Asian/Pacific Islanders. The remaining 18 DRB104 alleles known at the time of the study were not observed. Although not observed in the frequency study, seven previously unreported DRB104 alleles are also described.