Killer cell immunoglobulin-like receptor (KIR) locus profiles in the Tunisian population

Killer cell immunoglobulin-like receptors (KIRs) are a family of inhibitory and activatory receptors that are expressed by most natural killer (NK) cells. The KIR gene family is polymorphic: genomic diversity is achieved through differences in gene content and allelic polymorphism. The number of KIR loci has been reported to vary among individuals, resulting in different KIR haplotypes. In this study we report the genotypic structure of KIRs in 267 unrelated and healthy Tunisian subjects by polymerase chain reaction-sequence-specific primer (PCR-SSP) method.All 16 KIR genes were observed in the population with different frequencies; framework genes KIR3DP1 and KIR3DL2 and the nonframework genes KIR2DL1 and KIR2DP1 were present in all individuals. A total of 26 different KIR gene profiles and 54 subgenotypes were observed in the tested population samples. Genotype 1, with a frequency of 36.6%, is the most commonly observed in the Tunisian population.Our results showed that the Tunisian population possesses the previously reported general features of the Caucasian as well as African populations, with some additional interesting differences.Such knowledge of the KIR gene distribution in populations is very useful in the study of associations with diseases and in selection of donors for haploidentical bone marrow transplantation.     

Association of KIR2DL2 polymorphism rs2756923 with type 1 diabetes and preliminary evidence for lack of inhibition through HLA-C1 ligand binding

Killer cell immunoglobulin-like receptors (KIRs) on chromosome 19q13.4 regulate the function of not only human natural killer (NK) cells but also T cells. An increase in activating KIR– human leucocyte antigen ligand pairs has been associated with an additional risk to develop type 1 diabetes (T1D). T1D families [ n  = 184 (552 individuals); n  = 176 (528 subjects)], unrelated T1D patients ( n  = 380; n  = 394) and healthy controls ( n  = 315; n  = 401) from Germany and Belgium, respectively, were genotyped for the rs2756923 polymorphism within the KIR gene cluster haplotype B in exon 8 of the KIR2DL2 gene. We observed in both Germans and Belgians an overtransmission of the allele 'G' of the KIR2DL2-rs2756923 polymorphism (64.2% vs 35.8%, P  = 3 × 10⁻⁴ and 60.0% vs 40.0%, P  = 0.02, respectively). In addition, this allele was more frequent in German patients than in healthy controls (78.4% vs 21.6%, P  = 1 × 10⁻³). Preliminary results from a cytotoxicity assay suggest that inhibition of NK-cell cytotoxicity may be impaired in individuals carrying the rs2756923 G allele. These data suggest a potential role of the KIR2DL2-rs2756923 polymorphism in T1D in Germans and Belgians.     

Investigation of killer cell immunoglobulin-like receptor gene diversity in KIR3DL1 and KIR3DS1 in a transplant population

Several overlapping amplicons were used to obtain the sequence of genomic DNA covering most of the coding regions of KIR3DL1 and KIR3DS1 from a family and 77 bone marrow transplant patients and their unrelated donors. Alleles 3DL1*00101 and *002 were most frequently observed in addition to 12 other known 3DL1 alleles. A single 3DS1 allele, 3DS1*01301, was identified in the 31 of 32 individuals carrying this gene. Two new alleles, 3DL1*01702 and 3DS1*058, were characterized. Three samples appeared to carry the duplicated killer cell immunoglobulin-like receptor (KIR) haplotype observed in other studies based on the presence of 3DS1 and two 3DL1 alleles. Additionally, one sample appeared to carry a novel KIR haplotype containing one 3DL1 and two 3DS1 alleles.     

Distribution of killer cell immunoglobulin-like receptor genes in population of Vojvodina,Serbia

Background: Killer cell immunoglobulin-like receptors (KIRs) are glycoproteins regulating the response of natural killer (NK) cells and a few sub-sets of T-cells. The KIR gene frequencies and genotype content vary considerably among different ethnic groups.

Aim: The aim of this study was to analyse KIR gene polymorphism in the population of Vojvodina and to compare it with selected worldwide populations.

Subjects and methods: The studied sample consists of 134 healthy unrelated individuals, residents of different geographical regions of Vojvodina. DNA samples isolated from peripheral blood leukocytes by the silica-based extraction method were used in reverse PCR-SSO and PCR-SSP technique to detect the presence and absence of KIR genes.

Results: All 16 KIR genes, a total of 37 different KIR genotypes, were observed in the Vojvodina population with the presence of framework and pseudogenes in all individuals. The neighbour-joining phylogenetic tree shows that the Vojvodina population is in the same cluster with Croatians, Turkish, Russians, Czechs, Irish, Italians, French, Macedonians and Polish. The Vojvodina population shows polymorphism of the KIR gene family present in other European and European-derived populations studied previously.

Conclusion: The present study may serve as a reference for comparisons in further anthropological and disease association studies and also provide more informative data valuable for donor search strategy in haematopoietic stem cell transplantation.     

内蒙古蒙古族人群杀伤细胞免疫球蛋白样受体基因簇多态性研究

目的 研究中国蒙古族人群杀伤细胞免疫球蛋白样受体(killer cell immunoglobulin-like receptors,KIR)基因的携带频率、KIR基因型及其遗传规律.方法 采集90名内蒙古农牧区蒙古族个体的血样,应用序列特异性引物聚合酶链反应(polymerase chain reaction-sequence specific primer,PCR-SSP)方法分别扩增KIR基因簇16个基因,依据实验结果计算各基因的携带频率并查询样本的基因型,和已报道的24个其他人群的相关数据进行主成分分析、计算Nei氏遗传距离并绘制遗传树.结果 (1)蒙古族人群KIR 2DL2、2DS2携带率高于蒙古利亚人,低于高加索人.(2)蒙古族KIR基因单倍型AA为37.78%,高于高加索人,低于蒙古利亚人.(3)系统进化树显示蒙古利亚人和高加索人分别聚类,蒙古族人群则介于两者之间.结论 蒙古族其成因似与受到高加索人和蒙古利亚人的双重影响有关,表现为介于高加索人和蒙古利亚人之间的中间形式.

Abstract：

Objective To investigate the killer cell immunoglobulin-like receptor (KIR) gene frequencies and genotypes distributions in the Inner Mongolian population. Methods Ninety genomic DNA samples were extracted from blood samples of randomly chosen Mongolian individuals. Gene-specific PCR amplification was used to identify genes present or absent for 16 KIR loci. KIR genotype distributions were obtained and compared to that of 24 populations published in literatures using principal component analysis by SAS8.0 software. Genetic tree was constructed by the calculate Nei's genetic distance. Results (1) The frequency of KIR 2DL2,2DS2 in Mongolian individual is higher than that in north Mongoloid and less than that in Caucasian. (2) Haplotype AA was identified in 37.78% of individuals, which is higher than that in north Mongoloid and lower than that in Caucasian. (3) Mongolian was considered between north Mongoloid and Caucasian by principal component and genetic tree analysis. Conclusion Mongolian might be affected by the north Mongoloid and Caucasian, and showed intermediate between the two populations.     

Discrimination between the main activating and inhibitory killer cell immunoglobulin-like receptor positive natural killer cell subsets using newly characterized monoclonal antibodies

Natural killer (NK) cells are key components of the innate anti-viral and anti-tumour immune responses. NK cell function is regulated by the interaction of killer cell immunoglobulin-like receptors (KIR) with human leucocyte antigen (HLA) class I molecules. In this study, we report on the generation of KIR-specific antibodies allowing for discrimination between activating and inhibitory KIR. For this purpose, BALB/c mice were immunized with human KIR2DS2 recombinant protein. The precise specificity of KIR2DS2-specific clones was determined on KIR-transfected BW cells and KIR-genotyped NK cells. When used in combination with EB6 (KIR2DL1/2DS1) or GL183 (KIR2DL2/2DL3/2DS2), two KIR-specific monoclonal antibodies (mAbs), 8C11 (specific for KIR2DL1/2DL2/2DL3/2DS2) and 1F12 (specific for KIR2DL3/2DS2), discriminated activating KIR2DS1 (8C11⁻ EB6⁺) from inhibitory KIR2DL1 (8C11⁺ GL183⁻) and KIR2DL2 (1F12⁻ GL183⁺), while excluding the main HLA-Cw-specific KIR. Using these mAbs, KIR2DS1 was shown to be expressed on the surface of NK cells from all individuals genotyped as KIR2DS1⁺ (n = 23). Moreover, KIR2DS1 and KIR2DL1 were independently expressed on NK cells. We also determined the amino acid position recognized by the 8C11 and 1F12 mAbs, which revealed that some KIR2DL1 allele-encoded proteins are not recognized by 8C11. Because most available anti-KIR mAbs recognize both inhibitory and activating forms of KIR, these newly characterized antibodies should help assess the expression of activating and inhibitory KIR and their functional relevance to NK biology.     

Association of killer cell immunoglobulin-like receptor and human leucocyte antigen-Cw gene combinations with systemic lupus erythematosus

Killer cell immunoglobulin-like receptors (KIRs) are a diverse family of activating and inhibitory receptors expressed on natural killer (NK) cells and T cells, the genes of which show extreme polymorphism. Some KIRs bind to human leucocyte antigen (HLA) class I subgroups, and genetic interactions between KIR genes and their ligand HLA have been shown to be associated with several autoimmune diseases. The present study aimed to investigate whether the combinations of KIR genes and HLA-Cw ligands associate with the susceptibility of systemic lupus erythematosus (SLE). Polymerase chain reaction using sequence-specific primers was used to determine the genotypes of KIR genes and HLA-Cw alleles. We found that the frequencies of HLA-Cw07 were statistically significantly higher in the patient group than those in the control group (P = 0·009). KIR2DS1⁺HLA⁻Cw^Lys was more common in subjects with SLE compared to control subjects (P = 0·015). In addition, the frequency of KIR2DS1 was increased in SLE when KIR2DL1/HLA-Cw are absent, and the difference was significant (P = 0·001). KIR genotype and HLA ligand interaction may potentially influence the threshold for NK (and/or T) cell activation mediated through activating receptors, thereby contributing to the pathogenesis of SLE.     

Killer cell immunoglobulin-like receptor (KIR) genes in systemic sclerosis

A previous study has suggested that the combination KIR2DS2⁺/KIR2DL2^‐ was related to increased risk for systemic sclerosis (SSc), while others have failed to reproduce this finding. Our objective was to study this matter further and test the association of other KIR genes with SSc. One hundred and ten SSc patients and 115 healthy bone marrow donors were enrolled in a case–control study. Blood was collected for DNA extraction; typing of 15 KIR genes and human leucocyte antigen‐C (HLA‐C) was made by polymerase chain reaction with sequence specific primers (PCR–SSP), followed by electrophoresis on agarose gel. Patients underwent clinical evaluation, serology, Doppler echocardiography and chest high‐resolution computed tomography. The frequency of the inhibitory KIR2DL2 was significantly lower in patients [29·1% versus 65·2% in controls, P < 0·0001; odds ratio (OR) = 0·22, 95% confidence interval 0·12–0·40]. When combinations of activating and inhibitory KIR genes were analysed, the presence of KIR2DS2 in the absence of KIR2DL2 (KIR2DS2⁺/KIR2DL2^‐) was more frequent in patients than in controls (25·5% versus 1·7%, respectively; P < 0·0001; OR = 19·29, 4·24–122·26). However, the presence of both KIR2DS2 and KIR2DL2 (KIR2DS2⁺/KIR2DL2⁺) was more frequent in controls (57·4%) than in patients (28·2%, P < 0·0001), suggesting a preponderant protective effect of KIR2DL2 over KIR2DS2. Stratification for HLA‐C1 status did not change these results. No statistically significant associations were found between KIR phenotypes and clinical and laboratory features of SSc. Our results suggest a protective role of KIR2DL2⁺ phenotype and confirmed the association of the combination KIR2DS2⁺/KIR2DL2^‐ with increased risk for SSc.     

桥本甲状腺炎患者杀伤细胞免疫球蛋白样受体基因多态性分析

目的 探讨杀伤细胞免疫球蛋白样受体(killer cell immunoglobulin-like receptor, KIR)基因多态性与桥本甲状腺炎(HT)的关联性.方法 选择100例散发HT患者,260例无血缘关系的正常人作为对照,提取全血基因组DNA,采用序列特异性引物聚合酶链反应(PCR-SSP)的方法,对KIR2DL1～5、KIR3DL1～3、KIR2DS1～5、KIR3DS1及KIR2DP1共15个KIR基因进行检测,其中除KIR2DS5基因外,每个基因均采用2对不同的特异性引物.结果 HT病例组中KIR2DL5基因的基因频率较对照组显著降低(0.200 vs 0.312,RR=0.64,P<0.01).结论 KIR2DL5基因频率的降低可能与HT的发病相关.     

Association of killer cell immunoglobulin-like receptor genotypes with susceptibility to endometriosis

PROBLEM: Endometriosis is an immune-related chronic inflammatory disease with a polygenic predisposition. The aim of this study was to investigate whether polymorphisms in killer cell immunoglobulin-like receptors (KIRs) is responsible, in part, for genetic susceptibility to endometriosis. METHOD OF STUDY: The KIRs genotype was determined in 186 patients with endometriosis and 165 control women using polymerase chain reaction with sequence-specific primers. RESULTS: The frequency of KIR3DS1 was significantly decreased in patients compared with controls (32% versus 44%, P=0.028). KIR data were analyzed using a model comprised of three large groups, in which a gradient of activation/inhibitory potential derived from the combination of KIR and human leukocyte antigen (HLA) ligand genes was taken into account. The frequency of inhibitory KIRs/HLA-class I combination genotypes was significantly higher in patients than in controls (chi2=6.010, 2 df, P=0.0496). CONCLUSION: Our results suggest that polymorphism in KIRs may be associated with susceptibility for endometriosis.     

Diversity of killer cell immunoglobulin-like receptor genes in Indonesian populations of Java, Kalimantan, Timor and Irian Jaya

Killer cell immunoglobulin-like receptors (KIRs) regulate the activity of natural killer and T cells through interactions with specific human leucocyte antigen class I molecules on target cells. Population studies performed over the last several years have established that KIR gene frequencies (GFs) and genotype content vary considerably among different ethnic groups, indicating the extent of KIR diversity, some of which have also shown the effect of the presence or absence of specific KIR genes in human disease. We have determined the frequencies of 16 KIR genes and pseudogenes and genotypes in 193 Indonesian individuals from Java, East Timor, Irian Jaya (western half of the island of New Guinea) and Kalimantan provinces of Indonesian Borneo. All 16 KIR genes were observed in all four populations. Variation in GFs between populations was observed, except for KIR2DL4 , KIR3DL2 , KIR3DL3 , KIR2DP1 and KIR3DP1 genes, which were present in every individual tested. When comparing KIR GFs between populations, both principal component analysis and a phylogenetic tree showed close clustering of the Kalimantan and Javanese populations, while Irianese populations were clearly separated from the other three populations. Our results indicate a high level of KIR polymorphism in Indonesian populations that probably reflects the large geographical spread of the Indonesian archipelago and the complex evolutionary history and population migration in this region.     

Investigation of activating and inhibitory killer cell immunoglobulin-like receptors and their putative ligands in type 1 diabetes (T1D)

Genetic and environmental factors play important roles in predisposing an individual to the development of type 1 diabetes (T1D). Several studies have investigated the role of killer cell immunoglobulin-like receptors (KIRs) and their HLA-class I ligands in susceptibility to T1D development, but only some of these studies have demonstrated an association. KIRs and their corresponding HLA class I ligands were investigated in Saudi patients with T1D compared with healthy controls. No significant differences in KIR gene distribution were observed between T1D patients and healthy controls. However, the homozygous C1/C1 ligand was considered a risk factor in predisposing individuals to T1D, whereas C2/C2 and HLA-Bw4 were considered protective factors against T1D. KIR2DL2/2DS2-C1C1 and KIR2DL3-C1C1 were significantly associated with T1D, and KIR2DS1-C2C2 and KIR2DL1-C2C2 were significantly less frequent in T1D patients. Stratification of KIR-HLA class I ligands in terms of the absence/presence of specific genotypes has different indications for susceptibility to T1D.     

Killer immunoglobulin-like receptor and human leukocyte antigen expression as immunodiagnostic parameters for pelvic endometriosis

PROBLEM: We investigated host immunologic responses to endometriosis by comparing immune cell surface antigens in peripheral blood (PB) and peritoneal fluid (PF) from women with endometriosis with those in PB and PF from other patients. METHOD OF STUDY: Japanese women with endometriosis (n = 56) were compared with controls with other laparoscopic diagnoses (n = 68). PB and PF were collected at the time of laparoscopy for flow cytometry. RESULTS: No significant difference in phenotypic parameters of T cells (CD3, CD4, and CD8), B cells (CD19), natural killer (NK) cells (CD56), or monocytes/macrophages (CD14) was seen between women with and without endometriosis. However, increased killer immunoglobulin-like receptor (CD158a) expression by NK cells and decreased human leukocyte antigen (HLA)-ABC and -DR expression by macrophages, all suggesting decreased functional activation were found in endometriosis. These markers showed significant association with endometriosis by odds ratio, logistic regression, and decision tree analyses. CONCLUSIONS: Increased CD158a(+) NK cells in PB and PF indicated decreased NK cell cytotoxicity in endometriosis, while decreased HLA expression on PF macrophages suggested impaired antigen presentation. Thus, aberrant immune responses by NK cells and macrophages may represent risk factors for endometriosis.     

江苏汉族人群杀伤细胞免疫球蛋白样受体及其特异性配体HLA分析

目的:分析杀伤细胞免疫球蛋白样受体(KIR)及其特异性配体HLAⅠ类分子在江苏地区汉族人群的分布特点。方法:分别利用real-time PCR法和PCR-SSP方法对173例无血缘关系的江苏汉族健康人群进行KIR和HLA-Cw,HLA-Bw4分型,并分析KIR/HLA配对组合的类型和数量。结果:江苏汉族人群中,>92%的个体同时表达四种抑制性KIR(iKIR)(2DL1,2DL2/3,3DL1,3DL2)。2DL2/HLA-C1,2DL3/HLA-C1,2DL1/HLA-C2,3DL1/Bw4的频率分别依次分别为0.243,0.971,0.457,0.590;2DS1/HLA-C2,2DS2/HLA-C1的频率为0.162,0.231。54.3%的个体只表达2DL1而不表达相应的配体HLA-C2,32.9%的个体只表达3DL1而缺乏配体HLA-Bw4,另有5.8%的个体只表达HLA-Bw4而不表达3DL1。27.7%的个体同时表达3种iKIR/HLA,26%的个体同时表达两种iKIR/HLA,25.4%的个体只遗传一个iKIR/HLA配对,未发现3种iKIR/HLA同时缺失的个体。结论:在江苏汉族人群中,存在KIR与HLA表型分离现象,抑制性KIR/HLA配对表达高于刺激性KIR/HLA配对,约1/4个体只表达单个iKIR/HLA配对。     

Influence of KIR gene diversity on the course of HSV-1 infection: resistance to the disease is associated with the absence of KIR2DL2 and KIR2DS2

Herpes simplex virus type 1 (HSV-1) causes lifelong latent infections in most humans. Periodical virus reactivations from latency in the neurons of sensitive ganglia lead to transport to mucocutaneous regions and productive replication, which results in recurrent inflammatory herpetic lesions or in asymptomatic virus shedding. The medical consequences of such lesions and the frequency of recurrences vary greatly in different subjects. Furthermore, many infected individuals never suffer manifestations of the disease, even when exposed to stimuli that trigger clinical recurrences in other humans. The origin of the variability in the clinical course of HSV-1 infection remains unexplained. Herpesviruses and other pathogens sabotage the expression of major histocompatibility complex class I molecules by infected cells, thus subverting T-cell-mediated immunity. Subversion of antigen presentation is counteracted by natural killer cells, which survey the human leukocyte antigen (HLA) expression by specific receptors. These include the killer cell immunoglobulin-like receptors (KIRs), which are encoded by a complex of extremely diverse and rapidly evolving genes. Here, we analyze the contribution of KIR gene diversity to the variable clinical course of HSV-1 infection by comparing the distribution of these genes in humans with clinical manifestations of the disease with that in asymptomatically infected donors. This study provides preliminary evidence that the receptors KIR2DL2 and KIR2DS2 predispose to symptomatic HSV-1 infection and favor the frequently recurring forms of the disease. Possible contribution of the 'HLA-C1' ligand to HSV-1 disease was not statistically supported. Because of an absolute genetic linkage between KIR2DL2 and KIR2DS2, we could not determine which receptor was primarily responsible for the observed association, but our results suggest that presence in the genome of KIR2DL2 and KIR2DS2 hinders an effective cellular response to HSV-1.     

Killer cell immunoglobulin-like receptor genotypes in the Turkish population

One hundred eighty-seven healthy and unrelated volunteers from various regions of Turkey were selected for the study. Killer-cell immunoglobulin-like receptors (KIR) genotyping was performed by polymerase chain reaction using commercial sequence-specific oligonucleotide probe (SSOP) kits. Gene frequencies of the Turkish population were determined by direct counting of the positive and negative loci. The genotype data is publicly available in the Allele Frequencies Net Database under the population name “Turkey KIR pop 3” number “3399”.     

The effect of killer cell immunoglobulin-like receptor genotype on outcome of hematopoietic stem cell transplantation from matched sibling

The alloreactivity of natural killer (NK) cell after allogeneic hematopoietic stem cell transplantation (AHSCT) is regulated by the interaction between donor killer immunoglobulin-like receptors (KIRs) and recipient human leukocyte antigen (HLA)-class I molecules. The aim was to identify KIR genes, haplotypes and their HLA-class I ligands and to investigate their association with transplantation outcome. The study included 65 patient/donor pairs who received AHSCT from HLA-matched identical siblings. KIR genotyping was done for donors using reverse sequence specific oligonucleotide probes (rSSO) coupled with luminex technology, while HLA-C genotyping was performed in patients using rSSO strip assay. In multivariate analysis, KIR2DS4 was associated with significant reduced incidence of relapse (p?=?.002). A trend towards reduced incidence of relapse was also observed with more than two KIR B motifs (p?=?.09), whereas a significant increased relapse was associated with homozygous HLA-C2 ligand compared to combined C1/C2 and C1/C1 (p?=?.04). Activating KIR2DS3 was associated with rapid leukocyte engraftment (p?=?.02). While, KIR 2DL5 was associated with decreased CMV infection (p?=?.03) and better platelets engraftment (p?=?.05). KIR genes, haplotypes and HLA-C alleles have an impact on HSCT outcome. Better selection of donors with favorable KIR genotype can improve HLA-matched sibling HSCT outcome especially for AML patients.