HLA CLASS-I AND CLASS-II ALLELES AND HAPLOTYPES IN MEXICAN MESTIZOS ESTABLISHED FROM SEROLOGICAL TYPING OF 50 FAMILIES

We describe new information on the frequency and association of class II antigens (HLA-DR and NLA-DQ) of the major histocompatibility comple x (MHC) in Mexicans. The study includes HLA-B typing and its associati on with the HLA-DR antigens determined in 50 families, which included 100 individuals. This family study allowed the establishment of the pr ecise composition of the 200 HLA haplotypes, which cannot be obtained from unrelated individuals. The predominant antigens in decreasing ord er of frequency were B35, B39, and B61 at the B locus; DR4, DR5, and D R8 at the DR locus; and DQ3 at the De locus. The most common HLA-B,HLA -DR haplotype (considering broad specificities) was B16,DR4, with a fr equency of 8.0%. Five HLA-B,HLA-DR haplotypes showed significant delta values (observed vs. expected frequencies) after correcting for the n umber of comparisons. On the other hand, the most common NLA-DR,HLA-DQ haplotypes were DR4,DQ3 and DR5,DQ3 with a frequency higher than 10%. Ten of the 17 HLA-DR,HLA-De haplotypes had significant postcorrection delta values.