Polymorphism and distribution of HLA-DR2 alleles in Mexican populations

DRB1*15/16 nucleotide polymorphism was analyzed in 68 DR2 positive individu als(18 Mexican Mestizos, 30 Mazatecans and 20 Nahuas), carrying a total of 75 DR2 haplotypes. HLA-DR2 was one of the most frequent specificities detec ted in Mazatecans and Nahuas with gene frequency (gf) of 0.232 and 0.141, r espectively. In these populations DRB1*16 was the most frequent DR2 split ( gf = 0.183 in Mazatecans and gf = 0.135 in Nahuas), whereas in Mexican Mest izos the most frequent was DRB1*15 (gf = 0.065). Four DRB1-DQB1 combination s in Mexican Mestizos, two in Mazatecans and one in Nahuas were in linkage disequilibrium. In spite of the restricted polymorphism, there were differe nces on DRB1*15/16 alleles found in Mexicans. DRB1*1501 a Caucasian allele was predominant in Mexican Mestizos, whereas DRB1*1602 an Amerindian allele was characteristic on Indian populations. An important difference was dete cted among the Amerindian populations studied since DRB1*1502 was only pres ent in Mazatecans. This data corroborates the restricted polymorphism of DR B1*15/16 and the high frequency of DRB1"16 subtype in autochthonous America n populations and suggest that the differences in gene frequencies of DRB1* 15/16 alleles could be helpful in distinguishing each of these population. Human Immunology 62, 286-291 (2001). (C) American Society for Histocompatib ility and Immunogenetics, 2001. Published by Elsevier Science Inc.