Polymorphisms of killer immunoglobulin-like receptors (KIRs) and HLA ligands in northeastern Thais

Abstract

Killer cell immunoglobulin-like receptors (KIRs) are cell surface receptors on natural killer (NK) cells and subsets of T cells. The functions of NK cells are partly regulated by interactions between KIRs and HLA ligands on target cells. In this study, the presence or absence of 17 KIR genes and their known HLA ligands have been investigated in 235 unrelated individuals living in northeastern Thailand (NET). Subtypes of KIR2DS4 including full length (KIR2DS4F) and deleted forms (KIR2DS4D) have also been determined. Framework genes (KIR2DL4, 3DL2, 3DL3, and 3DP1) were found in all individuals and KIR genes belonging to the A haplotype (KIR2DL1, 2DL3, 3DL1, and 2DS4) were present in more than 90% of NET. KIR2DS4D (61.7%) was more common than KIR2DS4F (52.8%). A total of 33 different KIR genotypes were observed. Of these, three new genotypes were identified. The most common genotype (AA) was observed in 35.7% of NET, and HLA-C alleles bearing the C1 epitope (HLA-C1) had the highest frequency (97%). All individuals had at least one inhibitory KIR and its corresponding HLA ligand; 40.9% of NET had three pairs of receptor-ligand combinations, and 18.3% had all three receptor-ligand combinations of KIR2DL3+C1, 3DL1+Bw4, and 3DL2+A11. Surprisingly, the patterns of KIR gene frequencies in NET are more similar to those of Caucasians than Japanese, Korean, and Chinese. This is the first report on complete analysis of KIR and known HLA ligands in Thais. These data provide basic knowledge on KIR for further studies on disease associations and transplantation in northeastern Thais.

Novel KIR genotypes and gene copy number variations in northeastern Thais

“…Genotypes 1, 2, 3, 4, 5, 7 and 8 were commonly found (> 5% frequency) as seen in previous studies of the Thai population. To compare KIR genotype with other populations, the genotype frequencies of Asians (Chinese Han, Mongolian and north Indian), Europeans (Italian and English) and Amerindian (north Brazilian) were included, showing that genotype IDs 1 and 2 were the most common genotypes (> 10% frequency) in Amerindian, Europeans and most Asians (NETs, Thais, Chinese Han and Mongolian), whereas other genotypes varied among populations. Individually, the frequencies of all KIR genotypes in north Indians were < 10%, with the most common genotype found at 9·3%.…”

“…The typing results of 17 KIR genes obtained using PCR‐SSP were previously reported and compared with those obtained with the qPCR method . Copy numbers for all KIR genes ( KIR2DL1–5 , 2DS1–5 , 2DP1 , 3DP1 , 3DL1 , 3DL2 , 3DL3 and 3DS1) were determined in the Thai samples using a Roche LightCycler 480 at Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK.…”

“…Recently, genetic variation of KIR and their HLA ligands in northeastern Thais ( NETs) was reported, by conventional methods [sequence‐specific priming–PCR (PCR‐SSP) typing]. However, gene copy number variations of KIR have not previously been reported in Thais.…”

Killer immunoglobulin‐like receptor diversity in Malay subethnic groups of Peninsular Malaysia

“…Genotype ID: 1 is homozygous type AA and is the most frequent genotype (41 of 120) observed in all four Malay subethnic groups. This genotype contains haplotype A genes and was also reported by others as being predominant in various widely distributed Asian populations (Yawata et al ., ; Velickovic et al ., ; Chaisri et al ., ).…”

Phenotype frequencies of Rh (C, c, E, e), M, Mia and Kidd blood group systems among ethnic Thai blood donors from the north‐east of Thailand

“…Although there has been studied on RBC phenotype frequencies in ethnic Thai populations (Fongsarun et al, ), there are no data from north‐east Thailand. Our previous studies on other aspects of molecular genetics, such as human leucocyte antigens (HLA), human neutrophil antigens (HNA) and killer immunoglobulin‐like receptors (KIRs), revealed significant differences in frequency of alleles/molecules in different regions of Thailand (Chaisri et al, ; Romphruk et al, ; Simtong et al, ). Here, we report for the first time the antigen and phenotype frequencies of blood group systems (Rh, M, Mi a and Kidd) by gel technology among ethnic Thai blood donors in the north‐east of Thailand.…”