Killer Cell Immunoglobulin-like Receptors Gene Frequencies Research Articles

Gene and genotype frequencies of immunoglobulin-like natural killer cell receptors in the population of Samara region

Background. The using of killer-cell immunoglobulin-like receptor (KIR) composition data is of increasing interest in clinical practice to select an optimal donor for allogeneic hematopoietic stem cell transplantation for treatment of hematologic malignancies to reduce graft versus host disease and the risk of relapse. It is also of interest to study the frequencies of KIR genes and genotypes in different populations. For the Russian Federation, KIR gene and genotype frequencies have been described for only a few relatively small samples and have not been fully studied. The study of KIR gene and genotype frequencies has not been conducted for the Samara region population to date.Aim. To study the frequencies of KIR genes and genotypes in the population of Samara region and to compare the data with previously described Russian populations.Materials and methods. To study the frequencies of KIR genes and genotypes, molecular genetic typing of 142 CBUs from the public cord blood bank of the Samara Regional Medical Centre “Dynasty” was performed. Molecular genetic typing of KIR genes was performed by polymerase chain reaction with sequence-specific primers with subsequent visualization of products in agarose gel. 16 KIR genes and pseudogenes were analyzed: 2DL1, 2DL2, 2DL3, 3DL1, 3DL2, 2DS1, 2DS2, 2DS3, 2DS4, 2DS5, 3DS1, 2DP1, 3DL3, 2DL4, 2DL5, 3DP1. KIR gene frequencies were determined by direct counting. Genotypes were determined using Allele Frequencies database. A determination B-content group was performed using the Donor KIR B-content group calculator. Statistical analysis was performed using the χ2 test.Results. The highest frequency of KIR inhibitory genes was found for KIR2DL1 (98.6 %), KIR3DL1 (98.6 %), KIR2DL3 (96.5 %), KIR2DL5 (46.5 %), and KIR2DL2 (34.5 %). The most frequent among the activating receptor genes was KIR2DS4 (89.4 %), the frequencies of other KIR activating genes were KIR2DS2 – 45.1 %, KIR2DS1 – 35.9 %, KIR2DS3 33.8 %, and KIR2DS5 – 26.1 %. Comparative analysis of KIR gene frequencies in the population of Samara region and other Russian populations revealed certain differences. Significant differences in the frequencies of occurrence were found for KIR2DL3, KIR2DS4, KIR2DL2, KIR2DL5, KIR2DS3, KIR2DS5, as well as KIR2DP1 and KIR3DP1. Examination of 142 samples revealed 45 different genotypes: AA genotypes were detected in 30 % and Bx genotypes in 70 % of cases. AA genotype ID195 with a frequency of 5.6 % was detected, which has not been previously described in Russian populations. Among the Samara region population sample, only 3.5 % had the “best” status, 20.4 % had the “better” status, and 76.1 % had the “neutral” status of the B-content.Conclusion. The results obtained in this sample on the frequencies of KIR genes and genotypes differ from the previously published data for the Russian Federation. Of interest is the finding of a greater diversity of genotypes among a rather small study group, the detection of an atypical ID195 genotype, and the difference in the representation of B-content groups. The analysis of KIR genotypes in the population of Samara region can be used in the selection of optimal CBU and hematopoietic cell/bone marrow donors in addition to HLA typing. Studying the frequency distribution of KIR and HLA genes and genotypes can play a role in the study of fundamental aspects of human immunology and population genetics.

The KIR2DL2/HLA-C1C1 Gene Pairing Is Associated With an Increased Risk of SARS-CoV-2 Infection.

SARS-CoV-2 is the causative agent for the global COVID-19 pandemic; however, the interaction between virus and host is not well characterized. Natural killer cells play a key role in the early phase of the antiviral response, and their primary functions are dependent on signaling through the killer cell immunoglobulin-like receptor (KIR). This study measured the association between KIR/HLA class I ligand pairings and the occurrence and development of COVID-19. DNA of blood samples from 257 COVID-19 patients were extracted and used to detect KIR and HLA-C gene frequencies using single strain sequence-specific primer (SSP) PCR. The frequency of these genes was compared among 158 individuals with mild COVID-19, 99 with severe disease, and 98 healthy controls. The frequencies of KIR2DL2 (P=0.04, OR=1.707), KIR2DS3 (P=0.047, OR=1.679), HLA-C1C1 (P<0.001, OR=3.074) and the KIR2DL2/HLA-C1C1 pairing (P=0.038, OR=2.126) were significantly higher in the COVID-19 patients than the healthy controls. At the same time, the frequency of KIR2DL3+KIR2DL2-/HLA-C1+Others+ was lower in COVID-19 patients than in healthy individuals (P=0.004, OR=0.477). These results suggest that the protective effect of KIR2DL3 against SARS-CoV-2 infection is related to the absence of the KIR2DL2 gene. This study found no correlation between the frequencies of these genes and COVID-19 pathogenesis. Global statistical analysis revealed that the incidence of COVID-19 infection was higher in geographic regions with a high frequency of KIR2DL2. Together these results suggest that the KIR2DL2/HLA-C1C1 gene pairing may be a risk factor for SARS-CoV-2 infection.

Killer cell immunoglobulin-like receptors (KIR) genes can be an adequate tool in forensic anthropological studies: evaluation in a wide Caucasian Spanish population

ABSTRACT Most immune system polymorphisms have undergone molecular evolution largely due to natural selection driven primarily by host-pathogen interactions, showing significant human geographic expansion signs. Killer cell immunoglobulin-like receptors (KIRs) show great genetic and allelic variation among different populations. The aim of this study was to analyse the frequency of KIR genes in a large cohort of healthy Spanish Caucasians (SC) to be able to compare them with other world populations. A total of 609 healthy SC unrelated individuals were analysed and compared with 16 worldwide populations. KIR genotyping was analysed by PCR-SSO technique. Our results showed that all KIR genes were present in the Spanish population. iKIR2D genes of the Spanish population were similar in different European populations like Danish, Finland, Irish and Italian populations, Czech and Turkish populations but very different to Australian, Bornean, Chinese, Indian, Venezuelan, and Russian populations. KIR3DL1 gene frequency in the Australian population was significantly lower than the Spanish population. aKIR genes frequencies of the Spanish population were similar to European populations, but slight differences were found in English, Finnish, Irish and Macedonian populations. In conclusion, our results enrich the Caucasian genetic information resources of the KIR gene pool for genetic susceptibility diseases and forensic anthropological studies.

Distribution of human killer cell immunoglobulin-like receptors and ligands among blood donors of Catalonia.

Killer cell immunoglobulin-like receptors (KIR) belong to a diverse family of receptors present in NK cells and certain subsets of T cells. They bind to HLA class I molecules and, such as these, are highly polymorphic. This study is the first to determine KIR gene content diversity and perform high-resolution genotyping of corresponding HLA class I ligands in 445 unrelated blood donors resident in Catalonia (northeast Spanish region) and registered in the Blood and Tissue Bank of Barcelona between 2017 and 2018. The study was performed using a new next-generation sequencing method developed and validated by our group, with an important hands-on-time reduction and very cost-effectiveness. Thirty-eight KIR genotypes were observed. Haplotype combination frequencies were 24.49% for AA, 75.51% for BX. The most frequent genotype, found in 109 individuals (24.49%), was genotype ID 1. Seventeen genotypes occurred only once. Thirty individuals carried all KIR genes (genotype ID 6). We detected 46 HLA-A, 63 HLA-A-B, and 40 HLA-A-C alleles. A majority of individuals were heterozygous for C1/C2 (42.24%), 38.43% were homozygous for C1, and 19.33% were homozygous for C2. The most common KIR-HLA ligand pair was KIR3DL1-Bw4+, present in 75.73% of cases. No differences were found in KIR gene frequencies between the Catalan cohort and other Iberian Peninsula populations. Our findings will be useful for guiding further research evaluating the functional significance of KIR-ligand associations in specific diseases.

The association of HLA/KIR genes with non-small cell lung cancer (adenocarcinoma) in a Han Chinese population.

The host immune system plays a crucial role in the surveillance, recognition and elimination of tumor cells. Recent studies found that Human lymphocyte antigen class I (HLA I) genes, Killer cell immunoglobulin-like receptor (KIR) genes and HLA/KIR combinations play a role in the defense against tumor cells. To evaluated the associations between HLA I genes, KIR genes and HLA/KIR combinations and non-small cell lung cancer (NSCLC) in a Chinese Han population, a total of 229 patients with NSCLC (adenocarcinoma) and 217 healthy individuals were studied. Our results showed that the HLA-C*08:01 allele occurred at a significantly higher frequency in the NSCLCs compared with the controls (P=0.034). The HLA haplotype frequencies bearing HLA-A, -B, and -C loci between the NSCLC and control groups were not different (P>0.05). And there were no differences in the KIR gene, genotype and haplotype frequencies between the NSCLC and control groups (P>0.05). Also, there were no differences between the HLA/KIR combinations in the KIR3D genes and HLA-A3/A11, HLA-Bw4 ligands and KIR2D genes and HLA-C1/C2 ligands between the NSCLC and control groups (P>0.05). Our results indicate that the HLA-C*08:01 allele could be a risk factor for NSCLC (adenocarcinoma) in the Chinese Han population (OR=2.395; 95% CI: 1.359-4.221).

The influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers.

IntroductionPeriodontal diseases are highly prevalent inflammatory, multifactorial diseases. Smoking is one of the most important environmental risk factors for the development and severity of periodontal disease. Killer cell immunoglobulin-like receptors (KIRs) are members of the immunoglobulin (Ig) superfamily and play an essential role in the regulation of NK cell activity, allowing natural killer (NK) cells to sense and respond to human leukocyte antigen (HLA) class I. The aim of this study was to evaluate the influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers.Material and methodsThis study enrolled 400 Caucasian subjects (age range 25-69 years) from the West Pomeranian region of Poland. The subjects were categorized into four subgroups (smoking and non-smoking patients with periodontal disease; smoking and non-smoking subjects without periodontal disease – control subjects).ResultsThe differences of KIR gene frequencies between non-smoking patients and non-smoking control subjects as well as smoking patients and control subjects were not statistically significant. In multivariate regression analysis advanced age of patients and smoking were independent factors associated with increased frequency of periodontal disease.ConclusionsThe results of this study suggest that the main factor associated with increased risk of periodontal disease is smoking, whereas KIR presence/absence polymorphism is not a significant factor involved in the pathogenesis of periodontal disease.

P126 Exression of killer cell immunoglobulin like receptors among Arabs from the Kuwait national stem cell registy

Hematopoietic stem-cell transplantation (HSCT) is the curative approach for many patients with hematological malignancies. Despite improvements in HLA typing, it is unfortunately still impossible to prevent graft versus host disease (GVHD) in all cases and therefore can reduce the chances of achieving the curable goals of HSCT. An important immunological factor that influences the success of HSCT is the function of natural killer (NK) cells. NK cells are closely controlled by killer-cell immunoglobulin-like receptor (KIRs) which interact with specific HLA class I molecules. The presence or absence of individual KIR genes varies within and between populations, creating a diverse pool of KIR genotypes. Aim of this study was to investigate the KIR gene frequencies among 600 healthy Kuwaiti Arab unrelated volunteers donors. Methods KIR SSO genotyping was performed using the Luminex reverse SSO DNA. The study was performed on 600 random Kuwaiti individuals from the National Stem Cell Registry. Results The percentage for the presence of the KIR genes was found to be: KIR2DL1 95%, KIR2DL2 81%, KIR2DL3 91.5%, KIR2DL4 96%, KIR2DL5 62%, KIR2DP1 97%, KIR2DS1 34.3%, KIR2DS2 97.7%, KIR2DS3 53.1%, KIR2DS4 93.0%, KIR2DS5 67%, KIR3DL1 94.4%, KIR3DL2 99%, KIR3DL3 97%, KIR3DP1 98%, KIR3DS1 36%. The framework genes were present in almost 100% of the volunteers as expected. The donors were classified based on the number of B haplotype genes and A haplotype genes. Only 2% of the Kuwaiti subjects were of AA haplogroup genotype, making 98% Bx haplogroup genotype. Conclusion Findings of this study are crucial to characterize and to provide a new data on KIR genotype of the Kuwaiti Arab population. Ultimately it may improve HSCT matching outcome by choosing an HLA matched donor with NK-cell alloreactivity versus a non-alloreactive donor.

KIR and HLA genotyping of Japanese descendants from Curitiba, a city of predominantly European ancestry from Southern Brazil

We hereby report the KIR gene frequencies and the frequencies of HLA ligands of KIR for Brazilians of Japanese ancestry. A total of 51 individuals were genotyped for presence/absence of KIR (killer cell immunoglobulin-like receptors) genes and presence of HLA (human leukocyte antigens) ligands. KIR was genotyped using two pairs of sequence-specific primers (PCR-SSP) and HLA ligands were typed by LABType® SSO reagent kits (One Lambda, USA). These data are fully available in Allele Frequencies Net Database, under the population name “Brazil Curitiba Japanese KIR”.

Predominance of B haplotype associated KIR genes in Tamil Speaking Dravidians

Killer cell immunoglobulin like receptors (KIRs) are a group of activating (aKIRs) and inhibitory receptors (iKIRs) expressed on subsets of lymphoid cells. Their interaction with HLA class I molecules modulate the innate and adaptive immune response against infections and malignancies. KIR haplotypes varies in gene content and also at allelic level, thereby, distinguishing individuals and populations. Hence, the present study is aimed to determine the KIR gene diversity in Piramalai Kallar (PK) population of South India. The PK population shows diverged KIR gene frequencies and novel haplotypes than other South Indian populations. 52 different KIR gene profiles were identified and 18 of them were new in this population. In phylogenetic analysis the study population is positioned between African and Iranian population in the clade, which supports the South African ancestry of Indian population.

Killer cell immunoglobulin-like receptor (KIR) gene diversity in a population naturally exposed to malaria in Porto Velho, Northern Brazil.

Killer cell immunoglobulin-like receptors (KIR) are expressed mainly in natural killer cells and specifically recognize human leukocyte antigen (HLA) class I molecules. The repertoire of KIR genes and KIR-HLA pairs is known to play a key role in the susceptibilities to and the outcomes of several diseases, including malaria. The aim of this study was to investigate the distribution of KIR genes, KIR genotypes and KIR-HLA pair combinations in a population naturally exposed to malaria from Brazilian Amazon. All 16 KIR genes investigated were present in the studied population. Overall, 46 KIR genotypes were defined. The two most common genotypes in the Porto Velho communities, genotypes 1 and 2, were present at similar frequencies as in the Americas. Principal component analysis based on the frequencies of the KIR genes placed the Porto Velho population closer to the Venezuela Mestizos, USA California hispanic and Brazil Paraná Mixed in terms of KIR gene frequencies. This analysis highlights the multi-ethnic profile of the Porto Velho population. Most of the individuals were found to have at least one inhibitory KIR-HLA pair. Seventy-five KIR-HLA pair combinations were identified. The KIR-2DL2/3_HLA-C1, KIR3DL1_HLA-Bw4 and KIR2DL1_HLA-C2 pairs were the most common. There was no association between KIR genes, KIR genotypes or KIR-HLA pair combinations and malaria susceptibility in the studied population. This is the first report on the distribution of KIR and known HLA ligands in the Porto Velho population. Taken together, these results should provide baseline information that will be relevant to population evolutionary history, malaria and other diseases studies in populations of the Brazilian Amazon.

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.

Killer immunoglobulin-like receptor gene repertoire influences viral load of primary human cytomegalovirus infection in renal transplant patients.

Killer cell immunoglobulin-like receptors (KIR) are highly polymorphic members of the immunoglobulin superfamily, which influence the response of natural killer cells and some T-lymphocyte subsets. Analysis of a cohort of previously human cytomegalovirus (HCMV)-negative patients, who developed primary HCMV infection following HCMV-positive renal transplant (n=76), revealed an increase in the frequency of KIR genes located on the telomeric region of B haplotypes (Tel B). The presence of Tel B in combination with the KIR ligand HLA-C2 was significantly more frequent in this subgroup. These genetic factors were associated with resistance to HCMV infection in a second cohort (n=65), where the Tel B genes KIR2DL5, -2DS1, 2DS5 and -3DS1 were all significantly associated with high viral loads. Furthermore, the KIR haplotype Tel A when in combination with the KIR ligand HLA-C1 was significantly protective against the development of severe infection. Our results suggest that KIR are a significant factor in the control of primary HCMV infection, and that determination of KIR gene repertoire may help in detection of renal transplant patients who were most at risk.

Polymorphism of killer cell immunoglobulin-like receptors (KIR) and their HLA ligands in Graves' disease.

Killer immunoglobulin-like receptors (KIR) play a pivotal role in commencement of both innate and adaptive immunity. Dysregulation of KIRs is associated with an increased risk of autoimmune disorders. This study was designed to assess whether polymorphisms in KIR gene family and their respective HLA class I ligands confer protection or susceptibly to Graves' disease (GD). Eighty patients with confirmed GD (cases) and 176 healthy unrelated subjects (controls) were recruited. Using a polymerase chain reaction sequence-specific primer directed method (PCR-SSP), presence or absence of KIR genes and their HLA ligands were determined. No significant differences were observed between case and control groups regarding individual KIR gene frequencies (p > 0.05 in all cases). The frequency of group A haplotype (the most common KIR haplotype, encompassing 2DL1/2DL3/3DL1/2DS4/2DP1/3DP1/2DL4/3DL2/3DL3), was not different between individuals with and without GD. Moreover, among all other haplotypes (group Bx), no significant differences regarding distribution of centromeric and telomeric gene clusters were identifiable. Inhibitory/activatory gene contents were also comparable between the two groups. Four models of KIR-HLA interaction (inhibition, activation, unrestrained inhibition, and unrestrained activation) were constructed. No combination proved to confer susceptibility to, or offer protection against GD. It seems that the contribution of KIR gene polymorphism to natural killer cell dysfunction and other autoimmune abnormalities observed in GD is limited.

Killer cell immunoglobulin-like receptors in Thai patients with leukemia and diffuse large B-cell lymphoma

Natural killer (NK) cells are key components of the innate immune system that have been implicated in the immune response against tumor cells. Killer cell immunoglobulin-like receptors (KIR) regulate NK cell activity by interaction with specific human leukocyte antigen (HLA) class I. In this study, KIR gene polymorphisms and their HLA ligands were investigated in Thai patients with chronic myelogenous leukemia (CML) (n=60), acute myelogenous leukemia (AML) (n=60), acute lymphoblastic leukemia (ALL) (n=55), and diffuse large B-cell lymphoma (DLBCL) (n=60) compared with 150 healthy controls. The frequency of KIR3DL1 with HLA-Bw4 was significantly lower in DLBCL patients than in controls (P=0.0006, Pc=0.02), whereas no significant differences were seen in KIR gene frequencies and their ligands between leukemia patients and controls. This study suggest a role of inhibitory KIR with its ligand in the protection against DLBCL.

Presence of more activating KIR genes is associated with Hashimoto’s thyroiditis

Killer cell immunoglobulin-like receptors (KIR) regulate the effector function of natural killer (NK) cells and the subset of T cells with memory phenotype. The number and type of genes that encode KIR receptors substantially varied between individuals and between populations. Specific KIR receptors are known to be associated with certain diseases. The present study was undertaken to investigate if any specific KIR gene(s) is associated with the susceptibility to Hashimoto's thyroiditis (HT), an inflammatory disease characterized by lymphocytic infiltration of the thyroid gland and the presence of autoantibodies directed against thyroglobulin and/or thyroid peroxidase. DNA from 118 patients with HT and 120 healthy controls was characterized for the presence and absence of 11 variable KIR genes using a gene-specific PCR typing system. Although no significant difference in the frequency of individual KIR genes between patients and controls was detected, more patients carry the six activating KIR genes compared with the control group (11.8 vs. 4.1 %, p = 0.032, OR = 3.09, 95 % CI 1.07-8.89). The data suggest that augmented signals from multiple activating KIR receptors might exacerbate the activation of NK cells and T cell subsets against self-antigens, thus contributing to the pathogenesis of HT.

Natural killer cell activity and frequency of killer cell immunoglobulin‐like receptors in children with different forms of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) has three major onset types with widely varying clinical features: systemic, polyarticular and pauciarticular. We assessed natural killer (NK) cell function and killer cell immunoglobulin-like receptor (KIR) genotypes in patients with different JIA subtypes. Peripheral blood samples from 72 children with active JIA (systemic, 25; polyarticular, 24; pauciarticular, 23) and 25 controls were used for flow cytometric assessments of NK cell count, cytotoxicity, perforin, granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Samples from 220 children with JIA (systemic, 84; polyarticular, 72; pauciarticular, 64) and 150 controls were used for KIR2DS2, KIR2DS4, KIR3DS1, KIR2DL1, KIR2DL2, KIR2DL3 and KIR3DL1 typing by polymerase chain reaction with sequence-specific oligonucleotide probes. Compared with the controls, the patients with systemic JIA showed lower NK cell counts, cytotoxicity and perforin and granzyme B expression (p<0.05), while the patients with pauci- and polyarticular JIA showed higher perforin and granzyme B expression (p<0.05). NK cells produced higher level of TNF-α while lower level of IFN-γ in the pauci- and polyarticular JIA groups than in the systemic JIA group (p<0.05). No significant differences in KIR gene frequencies were found between the JIA subgroups and healthy controls, except for the positive frequency and locus frequency of KIR2DS4, which were lower in the systemic JIA group. Compared with poly- and pauciarticular JIA, systemic JIA is associated with decreased NK cell function, more IFN-γ and less TNF-α secretion of NK cell and lower KIR2DS4 frequency.

Analysis of KIR gene frequencies and HLA class I genotypes in breast cancer and control group

Breast cancer is the main cause of cancer-related death among women, with a 0.5% increase in incidence per year. Natural killer cells (NK) are part of the innate immune system recognizing class I HLA molecules on target cells through their membrane receptors, called killer cell immunoglobulin-like receptors (KIR). The aim of our study was to evaluate the association between the KIR genes and HLA alleles in patients with breast cancer and healthy controls. Two hundred thirty patients with breast cancer and 272 healthy controls were typed for HLA class I and KIR genes by PCR-SSO. When both groups were compared, the presence of inhibitory KIR2DL2 receptors was significantly higher in breast cancer patients than in healthy controls. No significant differences were found for HLA-C2 and HLA-Bw4. However, a higher frequency of HLA-C1 in breast cancer patients was observed. These findings suggest a potential role for the KIR gene system in breast cancer. Further studies to confirm this observation are warranted.

Study of the KIR gene profiles and analysis of the phylogenetic relationships of Rajbanshi population of West Bengal, India

The natural killer (NK) cells have distinct receptors called killer cell immunoglobulin-like receptors (KIR) which are responsible for regulating NK cell responses to infections and malignancy. The extensive variations in the number and type of KIR genes can be used as a tool to understand the differentiation of populations and also for tracing genetic background. In this study, we have aimed to analyze the KIR gene polymorphism in the Rajbanshi population of West Bengal, India. To our knowledge this is the first report on the KIR gene polymorphism in the Rajbanshis, a population widely distributed in the Terai and Dooars region of West Bengal, India. Herein, we have studied the gene distribution of 14 KIR genes (KIR3DL1-3DL3, KIR 2DL1-2DL5, 2DS1-2DS5 and 3DS1) and two pseudogenes (KIR3DP1 and 2DP1). The gene frequencies and genotypic frequencies were calculated, based on which statistical analyses were performed. The presence of a considerable number of genotypic profiles suggests substantial diversity in the KIR gene pool of the Rajbanshis in the region studied. Apart from the framework genes (KIR2DL4, 3DL2, 3DL3 and 3DP1) present in all the individuals, the gene frequencies of other KIR genes varied between 0.84 and 0.15. Moreover the KIR polymorphisms of the Rajbanshis were also compared with that of available published data of the populations of other ethnicities. Though the Rajbanshi population showed a tendency to cluster with other Indian population based on KIR gene frequencies, the influence of Tibeto-Burman Lineage on their KIR genotypic profiles cannot be overlooked. Furthermore, evidences from previously published data on Y chromosome haplogroup diversity study on Rajbanshis support the view. Our results will not only help to understand the genetic background of the Rajbanshi population, but also in tracing the population migration events in the North-Eastern part of India and in illustrating the extensive genetic admixture amongst the different linguistic groups of the country and also in KIR-related disease researches.

Analysis of KIR gene frequencies and HLA class I genotypes in prostate cancer and control group

Prostate cancer is the second most common cancer in men, with a significant increase in incidence and mortality in men over 50 years of age. Natural killer cells (NK) are part of the innate immune system recognizing class I HLA molecules on target cells through their membrane receptors, called killer cell immunoglobulin-like receptors (KIR). The aim of our study is to evaluate the association between the KIR genes and HLA alleles in patients with prostate cancer and healthy controls. Two hundred patients with prostate cancer and 185 healthy controls were typed for HLA class I and KIR genes by PCR-SSP. When both groups were compared, no significant differences were found for HLA-C group 1 and group 2, HLA-Bw4, HLA-A3 and A11. No difference was seen either in KIR frequency between patients with prostate cancer and controls. In conclusion, our data suggest no potential role for the KIR gene system in prostate cancer.

Study of KIR genes in Lebanese patients with tuberculosis

A total of 103 Lebanese tuberculosis (TB) cases and 38 controls without TB were studied for the killer cell immunoglobulin-like receptors (KIR) genotypic profile using polymerase chain reaction sequence-specific primers. Patients and controls were assigned to the AA, AB or BB genotypes based on their A or B haplotype genetic make-up, and KIR gene frequencies were compared. We found an increase in the KIR A haplotype in TB patients compared to controls, and only KIR 2DL3 was found to be significantly more prevalent among TB patients. This confirms the findings of another unique international study performed in the Mexican population showing a greater repertoire of inhibitory KIR genes among TB patients than controls.