Distribution of KIR genes in Han population in Yunnan Province: comparison with other Han populations in China

Killer cell immunoglobulin-like receptors (KIRs) show extensive variation among different populations. In this study, 404 unrelated individuals in Han population in Yunnan Province, China, were genotyped for the presence or the absence of 16 KIR genes using the multiplex PCR-SSP method. Our data showed that the inhibitory gene frequency of genes KIR2DL1, KIR2DL3, KIR3DL1, KIR2DL5 and KIR2DL2 was 0.930, 0.889, 0.789, 0.206 and 0.095, respectively, and the activating gene frequency of KIR2DS4, KIR3DS1, KIR2DS1, KIR2DS5, KIR2DS2 and KIR2DS3 was 0.795, 0.218, 0.196, 0.165, 0.095 and 0.087, respectively. In all, 44 distinct KIR genotypes were identified; genotype 1 was predominant with a frequency of 0.478, followed by genotypes 2 and 8 with a frequency of 0.121 and 0.077, respectively. Haplotype A outnumbered haplotype B by 2.39:1. In addition, phylogenetic tree and multidimensional scaling analysis (MDS) based on KIR genes in populations including Asian, African and Caucasians have been performed. Neighbour-joining tree analysis and the MDS plot showed that Han populations were clustered together with Asian and were separate from other populations. The Han populations in China were separated into northern and southern groups; the Yunnan Han population investigated in this study was clustered in the southern group. These results implied that the difference between northern and southern Han populations might reflect responses to a variety of locally acting epidemiological challenges.