Characterization of Killer cell immunoglobulin-like receptor (KIR) genotypes and haplotypes in Chinese Han population

We performed Killer cell immunoglobulin-like receptor (KIR) genotyping on 1271 individuals of Chinese Han origin including 102 families and 965 unrelated individuals. The families (with one child and both parents) were subjected for haplotype analysis. Forty-one different genotypes were identified. The frequencies of the KIR genotypes found in the family panel were confirmed by those found in the unrelated panel. The family study showed segregation of one A haplotype and at least 15 unique B haplotypes. The most commonly observed haplotypes in group B were B1, B2, and B3, present at a frequency of 10.05%, 6.62%, and 4.90%, respectively. On the basis of the combination of KIR genes, six centromeric and seven telomeric gene motifs have been identified. Motif cB02 was the most frequent haplotype B specific centromeric segment while tB01 was the most frequent haplotype B specific telomeric segment. The distinct distribution of KIR haplotypes in each population may reflect the history of directional and balancing selection of different races. The gene combinations of group A and B1/B2/B3 haplotype were the most frequent genotypes named as Bx1, Bx2, and Bx3, present at a frequency of 13.72%, 7.35%, and 4.41% in the family panel, and at a frequency of 15.86%, 10.15%, and 5.80% in the unrelated panel, respectively. Overall, this study showed the diversity of KIR haplotypes and genotypes in Chinese Han population and developed a criterion for distinguish KIR haplotypes/genotypes for the population. KIR genotyping and haplotype analysis should be useful for selection of the most optimum donor grafts with favorable KIR gene content for transplants.