Killer cell immunoglobulin-like receptor (KIR) genes and their HLA-C ligands in a Ugandan population

Killer cell immunoglobulin-like receptor (KIR) genes are expressed by natural killer cells and encoded by a family of genes exhibiting considerable haplotypic and allelic variation. HLA-C molecules, the dominant ligands for KIR, are present in all individuals and are discriminated by two KIR epitopes, C1 and C2. We studied the frequencies of KIR genes and HLA-C1 and C2 groups in a large cohort (n = 492) from Kampala, Uganda, East Africa and compared our findings with published data from other populations in sub-Saharan Africa (SSA) and several European populations. We find considerably more KIR diversity and weaker linkage disequilibrium in SSA compared to the European populations and describe several novel KIR genotypes. C1 and C2 frequencies were similar to other SSA populations with a higher frequency of the C2 epitope (54.9 %) compared to Europe (average 39.7 %). Analysis of this large cohort from Uganda in the context of other African populations reveals variations in KIR and HLA-C1 and C2 that are consistent with migrations within Africa and potential selection pressures on these genes. Our results will help understand how KIR/HLA-C interactions contribute to resistance to pathogens and reproductive success.