Polymorphism Of Killer Cell Immunoglobulin-like Receptors Genes In Yunnan Han Population

To characterize the gene polymorphisms,genotypes,and haplotypes of killer immunoglobulin(Ig)-like receptor(KIR) in Yunnan Hart population,the results obtained in this study will be useful as basic data for anthropology,transplantation immunity,and disease association studies.Methods150 unrelated healthy individuals were randomly selected from volunteer blood donors in Yunnan Han population and genotyped by PCR-SSP.KIR genotypes and haplotypes were assigned according to the standard model by Hsu et al.Linkage disequilibrium parameters for two loci were calculated using Arlequin3.1 software. Genetic distances were calculated using phylip3.67 software.Phylogenetic tree was constructed with frequencies of individuals having the KIR genes using the neighbor-joining method with the genetic distances between populations using MEGA4 software.Results(1) Framework genes 3DL3,3DP1,2DLA and 3DL2 were present in all individuals in Yunnan Han population,and the distribution of 2DL1,2DL3,2DP1, 3DP1~*003,3DL1 and 2DS4~*001 loci were common in this population,while the frequencies of 2DL2,2DL5,2DS1,2DS2,2DS3,2DS4~*003,2DS5,3DS1 and 3DP1~* 001 / 002 loci were relatively lower.(2) A total number of 30 different KIR genotypes were identified in Yunnan Han population,and the most common KIR genotypes were AJ(2,2) and AF(1,2) with the frequency of 26.67%and 17.33%,respectively.Furthermore,14 different KIR genotypes have been found in Yunnan Han population,which could not be assigned according to the standard model by Hsu et al.Among 14 KIR genotypes,13 genotypes have been observed in other populations.One novel genotype has been found in Yunnan Han population,which has not been observed in other populations so far.(3)15 different KIR haplotypes(2 group A and 13 group B) were identified, among which the haplotype 2 was the most popular haplotype with the frequency of 46.6%.One novel genotype could not be assigned to the haplotype according to the standard assign method.The frequencies of A and B haplotype were 69.4%and 30.6 %respectively,with the ratio of A:B being 2.27:1.(4) The subtype frequencies of KIR2DL5.1 and KIR2DL5.2 were 26.67%and 17.33%,respectively.Haplotype 8 contained both KIR2DL5.1 and KIR2DL5.2, while haplotype 6 contained either single KIR2DL5.1 or both subtypes.(5)We found 7 different combinations of inhibitory KIR genes and 16 different combinations of activate KIR genes present in different individuals.(6)Several strong positive and negative associations between different KIR pairs were found in Yunnan Han population.The most significant positive KIR associations were KIR2DL2/KIR2DS2,KIR2DL2/KIR2DS3,KIR3DL1/KIR2DS4,KIR2DS1/3DS1. The most significant negative KIR associations were KIR2DL1/KIR2DL2, KIR2DL2/KIR2DL3,KIR2DL3/2DS2.(7)Phylogenetic tree was constructed with the genetic distances which were calculated with frequencies of individuals having the KIP,genes between Yunnan Han population and other 22 populations. ConclusionsDistribution of KIP,genes in Yunnan Han population show rich KIR polymorphism,with its distinctive frequencies of KIR gene,genotype as well as haplotype.