HLA class I diversity in Kolla Amerindians

Abstract Human leukocyte antigen (HLA) class I polymorphism was studied within a population of 70 unrelated Kolla Amerindians from the far northwest of Argentina close to the Bolivian border. The results indicate that the HLA-A, -B, and -C alleles typical of other Amerindian populations also predominate in the Kolla. These alleles belong to the following allele groups: HLA-A∗02, ∗68, ∗31, ∗24, HLA-B∗35, ∗15, ∗51, ∗39, ∗40, ∗48, and Cw∗01, ∗03, ∗04, ∗07, ∗08, and ∗15. For the HLA-A locus, heterogeneity was seen for HLA-A∗02 with A∗0201, ∗0211, and ∗0222; and for A∗68 with ∗68012 and ∗6817, the latter being a novel allele identified in this population. Analysis of HLA-B identified heterogeneity for all Amerindian allele groups except HLA-B∗48, including the identification of the novel B∗5113 allele. For HLA-C heterogeneity was identified within the Cw∗07, ∗04, and ∗08 groups with Cw∗0701/06, ∗0702, ∗04011, ∗0404, ∗0803, and ∗0809 identified. The most frequent “probable” haplotype found in this population was B∗3505-Cw∗04011. This study supports previous studies, which demonstrate increased diversity at HLA-B compared with HLA-A and -C. The polymorphism identified within the Kolla HLA-A, -B, and -C alleles supports the hypothesis that HLA evolution is subject to positive selection for diversity within the peptide binding site.