HLA CLASS-II DNA TYPING IN 2 BRAZILIAN POPULATIONS

Brazil constitutes a melting pot of populations arising from three maj or groups, including Amerindians, Africans, and Europeans predominantl y from Portugal who were later supplemented by migrations from other E uropean countries. Although every possible combination of racial mixtu re exists in Brazil, we have selected for this study two groups of sub jects residing in Rio de Janeiro. A predominant White population, amon g whom some Amerindian admixture may exist, and a predominantly Africa n population having little admixture from the other races. We have use d the polymerase chain reaction (PCR) and hybridization with oligonucl eotide probes to perform a complete typing of the HLA class II alleles . We report the allele frequencies for HLA-DRB1, DQA1, DQB1 and DPB1. We also report on the postulated DR-DQ haplotypes based on family stud ies and observations in homozygous B-cell lines. These results may ser ve as background for various types of clinical studies in Brazilian po pulations.