HLA-B Allele, Genotype, and Haplotype Frequencies in a Group of Healthy Individuals in Colombia

Abstract

BACKGROUND: The sequencing of alleles of the HLA-B, a human leukocyte antigen (HLA) class I gene, was established as the most polymorphic of chromosome 6 and of the entire human genome. In this locus, the HLA-B*27 allele is highly polymorphic and has clinical relevance. Literature about the subtypes and singular frequency of these alleles in Colombia's healthy population is scarce. OBJECTIVE: The aim of this study was to establish the HLA-B allele, genotype, and haplotype frequencies in a healthy Colombian population and analyze their association with the sex and geographical distribution of the individuals studied. METHODS: This is a nonexperimental and descriptive study. The data from whole-blood samples whose HLA genes were genotyped by protocol with the Luminex 100/200 xMAP technology were evaluated. HLA-B*27 positivity was confirmed by the new-generation sequencing technology. The associations between the HLA-B alleles and demographic variables were evaluated by χ2 and Fisher exact tests. RESULTS: Twenty-seven HLA-B genotypes were identified in 255 individuals, with the highest frequencies for HLA-B*35 (44.7%), B*40 (19.6%), and B*44 (16.8%). Additionally, 89 HLA-B alleles were found; the most common were HLA-B*35:01 (6.7%) and B*40:02 (6.5%). Nine individuals tested positive for the HLA-B*27 allele with genotype and allele frequencies of 3.5% and 1.8%, respectively; the HLA-B*27:05:02 subtype predominated. CONCLUSIONS: Here, we report the most common HLA-B allele, genotype, and haplotype frequencies in a healthy Colombian population group and analyzed their association with the sex and geographical distribution of the individuals studied. Results for the HLA-B*27 allele confirm racial mixing in Colombia with a high degree of Caucasian influence, as well as the repopulation of Colombia's central region, attributed to the migration phenomena. Results agree with data published in Colombia that was obtained from cord blood samples.