HLA class II DNA typing in two Brazilian populations.

Brazil constitutes a melting pot of populations arising from three major groups, including Amerindians, Africans, and Europeans predominantly from Portugal who were later supplemented by migrations from other European countries. Although every possible combination of racial mixture exists in Brazil, we have selected for this study two groups of subjects residing in Rio de Janeiro. A predominant White population, among whom some Amerindian admixture may exist, and a predominantly African population having little admixture from the other races.

Alleles at four HLA class II loci determined by oligonucleotide hybridization and their associations in five ethnic groups.

The use of polymerase chain reaction (PCR) and oligonucleotide hybridization offers a new approach for the definition of HLA class II alleles. It has been possible to determine 43 alleles of DRB1, four of DRB3, two of DRB4, four of DRB5, eight of DQA1, and 14 of DQB1. These alleles are inherited together in members of families and form closely associated groups which are found repeatedly and in characteristic patterns in different populations.