Human leukocyte A and B antigen, gene and haplotype frequencies in the population of the city of São Paulo in Brazil.

Abstract

1. Antigen, gene and haplotype frequencies are important data for population analysis, paternity exclusion testing, genetic studies, and for organ transplantation selection. 2. We have studied the Class I histocompatibility antigens of 617 unrelated individuals from the city of São Paulo, Brazil, to determine antigen and gene frequencies of 16 HLA-A and 28 HLA-B antigens. Estimated haplotype frequencies were also determined, as well as the genetic distances of this population from European Caucasian and Negro populations. 3. A previously unknown linkage disequilibrium was detected for A23-B49 and a clear trend towards antigen frequencies intermediate between Caucasoid and Negro populations was observed.