Distribution of KIR genes and KIR2DS4 gene variants in two Mexican Mestizo populations

Killer immunoglobulin-like receptors (KIR) are transmembrane proteins that regulate NK and T cell subsets by recognizing HLA-I molecules as ligands. The KIR gene family consists of 16 genes, located at chromosome 19q13.4. KIR gene frequencies vary among populations. In Mexico, HLA and genetic ancestry studies show that Mestizo populations have different genetic backgrounds based on admixture with European, African, and Asian ancestry. This study aimed to evaluate the frequencies of KIR genes and genotypes in Guerrero and Jalisco, two Mexican Mestizo populations located in the south and the west of the country, respectively, and to compare these frequencies with those of other populations. KIR genotyping was performed by SSP-PCR. We observed that KIR gene frequencies were similar in both populations. There were 24 genotypes observed in Guerrero, 38 genotypes observed in Jalisco, 15 genotypes shared in both populations and 32 genotypes unique to one population or the other. In 10 individuals, nine novel genotypes were identified. KIR2DS4 gene variants showed significant differences: The KIR2DS4full gene was more common in Guerrero (p < 0.0001), and the KIR2DS4del variant was more common in Jalisco (p < 0.05). Differences in KIR2DS4 gene variants and genotypic profiles could be influenced by the genetic admixture in both regions.