Population and family studies of HLA-DR4 by use of oligonucleotide typing.

Using PCR and DR4 group-specific primers and SSO's we have examined DRB1*04 nucleotide polymorphisms in a population of 123 DR4-positive individuals (86 NAC, 27 Hispanics and 10 African Americans) from New York carrying a total of 134 DR4 haplotypes. We found that the distribution of DRB1*04 alleles on DR4 haplotypes differs in these three ethnic groups. In this relatively small population, certain alleles such as DRB1*0406 and 0411 were encountered only in Hispanics, while others such as DRB1*0403, 0408 and 0409 were found only in NAC (North American Caucasians). Such differences may be important in studies of HLA-DR4 and disease associations. Evidence from MLC and PLT studies of an HLA-B/DR crossover family, which was informative for the segregation of HLA-DRB1*0406 and DRB1*0407, supports the concept that subtypes of HLA-DR4 and/or associated HLA-DP alleles elicit T-cell alloreactivity, and may thus play a role in transplantation.