Distribution of killer cell immunoglobulin-like receptor genes and combinations with HLA-C ligands in an isolated Han population in southwest China

Human natural killer cells express killer cell immunoglobulin- like receptors (KIRs), which interact with human leukocyte antigen (HLA) class I molecules. KIR/HLA combinations play an important role in innate and adaptive immunity. In the current study, 16 KIR genes were analyzed in an isolated Han group living in the Fengyandong (FYDH) region in the Yunnan province of southwest China. The framework KIR genes 3DL2, 3DL3, 3DP1, and 2DL4 were found in all individuals. A total of 22 distinct KIR genotypes were observed, four of which were unknown previously. Genotype 1 (N = 52, 55.9%) was the predominant genotype. Analysis of inhibitory and activating KIR and HLA-C ligands showed that all individuals displayed at least one inhibitory or activating KIR/HLA-C pair. One KIR/HLA-C pair was the most frequent (67/93), followed by two pairs (21/93), and three pairs (6/93). The comparison of KIR and HLA frequencies between FYDH and a local Han population showed that the two populations showed similar frequencies for the KIR genes. In contrast, the distribution of HLA alleles and haplotypes showed significant differences between them.