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 DRB104 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 DRB104 alleles on DR4 haplotypes differs in these three ethnic groups. In this relatively small population, certain alleles such as DRB10406 and 0411 were encountered only in Hispanics, while others such as DRB10403, 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-DRB10406 and DRB10407, 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.