Killer Immunoglobulin-like Receptors Genes Research Articles

Killer immunoglobulin-like receptor and their HLA ligands in Guillain–Barré Syndrome

Guillain–Barré Syndrome (GBS) is an inflammatory neuropathy that occurs in some individuals after exposure to an infectious illness. We investigated the role of Killer-immunoglobulin-like receptors (KIR) and their HLA ligands as potential genetic factors in the pathogenesis of GBS. These receptors are involved in the innate immune response to infections.Whilst no significant differences in the frequencies KIR genes were found, HLA-C2 and HLA-B Bw4-T were more frequent in subjects with GBS than controls (p<0.001). The inhibitory pairs KIR-2DL2/HLA-C2 and KIR-3DL1/HLA-B Bw4-T were more frequent in GBS than controls (all p<0.005).We propose that NK cell inhibition is an important factor in the pathogenesis of GBS.

KIR and KIR ligand polymorphism: a new area for clinical applications?

Killer immunoglobulin-like receptors (KIRs) play an essential role in the regulation of natural killer (NK) activity, allowing NK cells to sense and respond to human leukocyte antigen (HLA) class I downregulation, an important hallmark for viral infections and tumor transformation. KIR and HLA genes are located on different chromosomes and KIR/HLA class I interaction represents an example of genetic epistasis in which the presence of receptor/ligand pairs is necessary for the induction of functional activity, while the presence of one in the absence of the other is not sufficient to influence NK cell function. Due to the high degree of HLA class I and KIR gene variability, KIR/KIR-ligand (KIR-L) interactions are extraordinarily diverse. KIR polymorphism arises from both haplotypic and allelic variations and was shaped by natural selection. KIR variability affects NK cell education influencing the KIR repertoire, KIR expression, the strength of KIR/KIR-L interactions and the capability to deliver signals. Moreover, it may influence NK cell function during infections, autoimmune diseases, pregnancy and allogeneic transplantation. This review summarizes the genetic and functional features of KIR/KIR-L interactions and gives an overview of their potential relevance in clinical studies.

Specific KIR and HLA Genotypes Affect Outcomes Of Single-Agent Anti-CD20 Immunotherapy Of Follicular Lymphoma

Lymphoma immunotherapy with anti-CD20 antibody (rituximab) acts primarily through Antibody Dependent Cellular Cytotoxicity (ADCC), implying a role for NK cells. The activation and inhibition of NK cells are influenced by Killer Immunoglobulin-like Receptors (KIRs) and their HLA ligands. To evaluate the involvement of NK cells in response to immunotherapy, we investigated the role of both KIR and HLA polymorphisms in response to single agent rituximab. We have analyzed the relationship between patient genotype and clinical parameters to determine if there are beneficial KIR/HLA interactions that can lead to improved clinical outcome. Methods204 follicular lymphoma (FL) patients participating in the Eastern Cooperative Oncology Group (ECOG) RESORT trial (E4402) were treated with rituximab. The patients who showed an initial response were randomized into two different rituximab treatment regimens. Approximately 70% of FL patients showed initial response to 4 weekly doses of rituximab, and were randomized between arm A: therapy “as needed” (4 weekly doses, only upon progression) or arm B: scheduled maintenance (1 dose every 13 weeks). Clinical outcomes analyzed included duration of response, time to rituximab failure (TTRF), time to cytotoxic therapy (TCT) and decrease in tumor size. The data presented here represent both treatment arms combined, i.e. arms A+B, for all clinical data parameters mentioned. Genomic DNA samples were used for genotyping patients for the presence of 15 KIR loci using a Real Time PCR-based method as previously published (Alves, Tissue Antigens, 2008). HLA specificities corresponding to KIR ligands (HLA-C1, C2, Bw4 and ABw4) were typed using a combination of PCR-SSP methods (Olerup and Invitrogen). ResultsThose patients homozygous for HLA-C1 (C1C1) showed a trend towards a longer duration of response (p=0.06) as compared to those that were heterozygous (C1C2) or homozygous for HLA-C2 (C2C2). A similar difference was observed where patients that were HLA-C1 positive [C1+ (C1C1 or C1C2)] showed a trend towards longer TTRF (p=0.071), as well as a significantly longer TCT (p=0.003), compared to C2C2 patients. Further analyses revealed that the influence of these HLA C specificities on clinical outcome could be related to the presence or absence of inhibitory and/or activating KIR genes. Specifically, HLA-C1 is a ligand for the inhibitory KIR genes 2DL2 and 2DL3. Among the patients who had the KIR2DL2 inhibitory gene (KIR2DL2+), those that were C1+ showed a prolonged duration of response (p=0.049), TCT [Figure 1A, (p=0.003)] and TTRF (p<0.001)] compared to KIR2DL2+ patients who were C2C2 and thus lacked the C1 cognate ligand. Similarly, KIR2DL3+ patients that were C1+ had a significantly longer TCT (p=0.007) than patients that were C2C2, but significant effects were not observed for these KIR2DL3+/C1+ patients with respect to the three other analyzed clinical parameters. Therefore, further studies are required to confirm that KIR2DL3 has an effect independent of other KIRs. [Display omitted] [Display omitted] HLA-C2 alleles are ligands for an activating KIR gene, KIR2DS1. The observed HLA-C genotype effect on clinical outcome could potentially be conveyed by the interaction of HLA-C2 with KIR2DS1. Among the C2C2 patients, KIR2DS1+ patients had a significantly shorter TTRF than those without KIR2DS1 (p=0.023), as well as a significantly smaller decrease in tumor size (p=0.039), implying that the interaction of the activating KIR receptor (KIR2DS1) with its cognate ligand (HLA-C2) conveys a disadvantage to patient outcome. ConclusionSingle-agent rituximab immunotherapy of FL reveals differences in outcomes based on KIR and HLA polymorphisms. The HLA-C2 homozygous individuals seem to be at a disadvantage. This may relate to 2 significant observations highlighting diverse effects of inhibitory and activating KIR-HLA interactions leading to NK cell “licensing” and “hyporesponsiveness”, respectively. Specifically, the data from this study are consistent with: A) a beneficial effect from inhibitory KIR2DL2 and KIR2DL3 interaction with HLA-C1, and B) a detrimental effect due to the contribution of activating KIR2DS1 interacting with its ligand HLA-C2.BG, AKE and WW are co-first authors. Disclosures:Horning:Genentech: Employment, Equity Ownership. Kahl:Genentech: Consultancy, Research Funding.

Donor-Recipient Matching For Killer Immunoglobulin-Like Receptor Genotypes Confers Protection Against Graft Versus Host Disease Without Affecting Disease Relapse After Allogeneic Hematopoietic Cell Transplantation

Background Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative therapy for malignant and non-malignant hematological disorders. Unfortunately, complications of HCT, primarily graft versus host disease (GVHD) and relapse of the underlying disease are substantial. In Alberta, all HCTs are performed with antithymocyte globulin conditioning and &gt;95% of these use HLA matched donors. However, in spite of that approximately 35% Albertan HCT recipients die or suffer long-term from GVHD while another 20% die due to disease relapse. Unfortunately, strategies/treatments aiming to control GVHD in most cases lead to increase in the rate of disease relapse and infections. In the recent years, the natural killer (NK) cell genetic system has garnered substantial research interest as an immunogenetic system that significantly influences HCT outcomes. The complexity of NK cell function is modulated by a series of activating and inhibitory cell surface receptors known as the Killer Immunoglobulin-like Receptors (KIR). Here we set out to determine the influence of KIR matching between HCT donor and recipient pairs on allogenic HCT complications. Study design Hypothesizing that donor-recipient KIR gene/profile mismatch would affect the allo-HCT outcomes, we genotyped 92 (discovery cohort) and 111 (validation cohort) allo-HCT pairs by Luminex-based rSSO method. The KIR genotypes were classified into AA and Bx genotypes on the basis of KIR gene constitution of the individual. Donor (D) and recipients (R) were ‘matched' for KIR genotypes when both carried either AA (two copies of group A haplotypes) or B/x (at least one copy of group B haplotype) genotypes. Effect of KIR matching on significant GVHD (described as grade 2-4 acute GVHD or chronic GVHD needing systemic therapy) as well as disease relapse was analyzed using binomial regression and Kaplan-Meier statistics. Results As observed in both the discovery and validation cohorts, a significant protection against GVHD was conferred upon when both the donor and recipient were matched for the KIR genotypes (HR=2.224; p=0.01) without any effect on disease relapse (HR=1.098; p=0.934) (figure1). Conclusions In spite of D-R matching for major immunogenetic determinants like HLA, complications of allogeneic HCT are significant. Since GVHD represents a flip side to graft-vs-leukemia (GVL) reaction, strategies to decrease GVHD in most cases have resulted in increased relapse. Matching donor and recipients for KIR genotypes can offer a significant protection against GVHD without increasing the risk of disease relapse. Disclosures: No relevant conflicts of interest to declare.

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Aim Natural Killer (NK) cells, first in line of defense against tumors and infections are the earliest lymphocytes to recover after Hematopoietic Cell Transplantation. NK cell responses are regulated by activating and inhibitory receptors known as Killer Immunoglobulin-like Receptors (KIR). It is still not known which NK cell subsets elicit anti-cancer or anti-viral immune response and if target induced NK cell responses are influenced by KIR gene content. Here we assessed in healthy individuals whether different NK cell subsets elicit unique immune responses against different targets (leukemia cells or herpes viruses), and if this difference is a function of individual’s KIR gene content. Methods PBMNCs from 50 healthy donors were stimulated with a leukemic cell line (K562) and a herpesvirus (Epstein-Barr virus, EBV). A 5-colour flow cytometry based estimation of cytotoxicity (CD107a expression) and cytokine (IFN- γ ) production was performed for both regulatory (CD56 bright CD16 neg ) and cytolytic (CD56 dim CD16 pos ) NK cells. KIR gene content was obtained by Luminex based rSSO method. Results Unique target induced patterns of responses were observed with different NK cell subsets. K562 cells induced degranulation with or without IFN- γ production. Contrarily, EBV induced NK cells exhibited all single (IFN- γ production and degranulation alone) and bifunctional (IFN- γ production and degranulation together) responses. In contrast to cytolytic NK cells, which in general exhibited a bifunctional response against both targets, regulatory NK cells were primarily only IFN- γ producers. High number of activating KIR genes (B/x genotypes) showed significant correlation with IFN- γ production but not with degranulation. Conclusions NK cell subsets elicit unique immune responses against different targets, some of which are influenced by the KIR gene content. Assessment of post-HCT recovery of these target-specific functional NK cell subsets and their KIR content will be important for the prediction of HCT outcomes.

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Uncontrolled reactivation of Epstein-Barr virus (EBV) leading to post-transplant lymphoproliferative disorder (PTLD) is one of the major complications of T-cell depleted HCT associated with a high risk of mortality. Given the fact that NK cells are first in line of defense against viral infections, and are among the earliest to reconstitute after HCT, they are deemed important in the immunopathogenesis of EBV complications. Their exact role in this process, however, remains elusive. The complexity of NK cell response is a function of a series of activating and inhibitory cell surface receptors known as Killer Immunoglobulin-like Receptors (KIR), which sense perturbations in HLA expression after viral transformation of the target cell. Here, we set out to determine whether and how KIR gene repertoire of HCT donors and/or recipients influences the development of PTLD after allo-HCT. 92 HCT donor-recipient pairs and 50 healthy individuals were KIR genotyped by Luminex-based rSSO method. The KIR repertoires were classified into AA and Bx genotypes as well as into centromeric and telomeric linkage groups. PBMNCs from healthy volunteers were stimulated with EBV lysate to enumerate EBV-induced NK cell response (degranulation and/or IFN γ production). Donor Centromeric KIR linkage group (2DS2-2DL2-2DS3-2DL5B) was strongly associated with the incidence of PTLD (p = 0.01, OR = 7.1). Further, the number of EBV induced IFNg producing and/or degranulating NK cells were significantly lower in individuals with than without centromeric KIR linkage group. NK cell responsiveness, a function of KIR gene repertoire has a profound effect on the development of PTLD. KIR genotype based identification of HCT recipients at high risk of developing PTLD will enable closer monitoring of EBV DNAemia and facilitate prompt therapy.

HLA and Killer Immunoglobulin-like Receptor Genes as Outcome Predictors of Hepatitis C Virus–Related Hepatocellular Carcinoma

We evaluated the impact of the killer immunoglobulin-like receptors (KIR) of natural killer (NK) cells and of their HLA ligands over the clinical outcome of hepatitis C virus (HCV)-related hepatocellular carcinoma after curative treatment by either surgical resection or radiofrequency thermal ablation (RTA). Sixty-one consecutive patients with HCV-related hepatocellular carcinoma underwent KIR genotyping and HLA typing. A phenotypic/functional characterization of NK cells was carried out in patients with different KIR/KIR-ligand genotype. Activating KIR2DS5 was associated with significantly longer time to recurrence (TTR) and overall survival (OS; P < 0.03 each). Homozygous HLA-C1 (P < 0.02) and HLA-Bw4I80 (P < 0.05) were expressed by patients with significantly better OS, whereas HLA-C2 (P < 0.02) and HLA-Bw4T80 (P < 0.01) were associated with a worse OS. Multivariate analysis identified as parameters independently related to TTR the type of treatment (surgical resection vs. RTA; P < 0.03) and HLA-C1 (P < 0.03), whereas only KIR2DS5 was an independent predictor of longer OS (P < 0.05). Compound KIR2DL2-C1 and KIR3DS1-Bw4T80 genotypes were associated with better TTR (P < 0.03) and worse OS (P = 0.02), respectively. A prevalent cytotoxic (CD56(dim)) NK phenotype was detected in patients with both longer TTR and OS. Cytotoxic capacity measured by upregulation of CD107a was significantly higher in subjects with HLA-C1 alone or combined with KIR2DL2/KIR2DL3. These results support a central role of NK cells in the immune response against hepatocellular carcinoma, providing a strong rationale for therapeutic strategies enhancing NK response and for individualized posttreatment monitoring schemes.

Allelic Polymorphisms of Inhibitory Killer Immunoglobulin–Like Receptor Natural Killer Cell Function Can Also Influence the Graft-Versus-Leukemia Response

Allogeneic hematopoietic stem-cell transplantations (HSCT) are recognized as a potentially curative treatment of choice for patients with acute leukemia and certain types of lymphoma who fail to sustain an initial complete remission, and are a favored option for patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) in first remission who are at high risk of relapse. Although allogeneic HSCTs entail significant risks, they also confer on the transplantation recipient an enhanced resistance to disease recurrence that is not observed after autologous or syngeneic HSCT. The basis for this graft-versus-leukemia effect is complex and still poorly understood. However, both innate and adaptive immune responses that are directed against leukemia cells have been implicated, particularly the contributions of donor-derived natural killer (NK) cells and those of T cells that are specific for either alloantigens that are broadly expressed or differentially expressed by hematopoietic cells of the host, or oncofetal and disease-specific antigens that are aberrantly expressed by leukemia cells. NK cells can be activated through a broad array of activating receptors, such as NKG2D, the natural cytotoxicity receptors NKp30, NKp44, NKp46, and NKp80, and activating receptors of the killer immunoglobulin–like receptor (KIR) complex. These receptors endow NK cells with the capacity to distinguish and respond to autologous cells that differentially express their respective ligands in response to viral infection, malignant transformation, or other types of stress. The KIRs are encoded by a complex of genes on chromosome 19. The KIRs inherited on each haplotype differ in content and function and include KIRs that inhibit or activate the NK cell on binding to their cognate ligands. The ligands for inhibitory KIRs are HLA class I alleles. KIR2DL3 binds HLA-C alleles that contain asparagine at position 80 (C1 alleles), whereas KIR2DL1 binds HLA-C alleles bearing lysine at that position (C2 alleles). KIR3DL1 binds HLA-BW4, whereas KIR3DL2 binds HLA-A3 and -A11 alleles. The activating KIR2DS4 is also known to bind HLA alleles (HLA-A3, -A11, or certain HLA-C alleles). KIR2DS1, like 2DL1, can also bind to HLA-C2 alleles. However, if the 2DS1 donor is also homozygous for an HLA-C2 allele (C2/C2), the NK cells are rendered hyporesponsive or tolerant. The ligands for the other activating KIRs that induce NK cytotoxic activity are unknown. The KIR genes exhibit significant diversity at two levels: allelic polymorphisms within the KIR genes themselves, and differences in the number and type of activating and inhibitory KIR genes inherited on a given haplotype. Analysis of the KIR gene complex has led to the recognition of a series of KIR gene haplotypes that can be divided into two major groups, each containing distinctive sets of KIR genes in their centromeric and telomeric regions. Group A KIR haplotypes differentially contain genes for four inhibitory receptors, KIR2DL3 and KIR2DL1 in the centromeric region and KIR3DL1 and KIR3DL2 in the telomeric region, but only one activating receptor, KIR2DS4. In contrast, KIR B haplotypes contain the inhibitory receptor KIR2DL2 and the activating receptor 2DS2 in the centromeric region and variably contain three activating receptors, 2DS1, 2DS3, and 2DS5, and one inhibitory receptor, 2DL5, in the telomeric region (Fig 1). Because NK cells can be activated through many receptors that encounter their ligands on stressed cells, control of NK cell activity is both essential and necessarily nuanced. Active NK cell tolerance is provided by inhibitory KIR receptors that continuously encounter their cognate class I HLA ligand on normal cells in their environment. These so-called licensed NK cells are differentially armed to distinguish cells that do or do not express their cognate HLA ligand. Detection and binding of this self-ligand on a potential target by inhibitory KIRs induces an inhibitory response. However, if the NK cell’s inhibitory KIR does not encounter its HLA ligand, and expression of ligands for activating KIRs is sufficient, the NK cell’s cytolytic complex is activated and the target is lysed. Additional mechanisms are also operative in the control of NKcell–mediated autoreactivity. Because inheritance of HLA haplotypes on chromosome 6 and KIR haplotypes on chromosome 19 are independent, most individuals inherit inhibitory KIRs for which the cognate class I ligand is not present in the host’s HLA genotype. Unlike T cells, NK cells that express KIRs that develop in the absence of cognate HLA ligands are not deleted. Rather, these so-called unlicensed NK cells continue to be generated but are functionally hyporesponsive JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 31 NUMBER 30 OCTOBER 2

Human papillomavirus, high-grade intraepithelial neoplasia and killer immunoglogulin-like receptors: a Western Australian cohort study

BackgroundHuman papillomavirus (HPV) is the causative agent in cervical cancer and HPV genotypes 16 and 18 cause the majority of these cancers. Natural killer (NK) cells destroy virally infected and tumour cells via killer immunoglobulin-like receptors (KIR) that recognize decreased MHC class I expression. These NK cells may contribute to clearance of HPV infected and/or dysplastic cells, however since KIR controls NK cell activity, KIR gene variation may determine outcome of infection.MethodsKIR gene frequencies were compared between 147 patients with a history of high-grade cervical intraepithelial neoplasia (CIN) and a control population of 187, to determine if any KIR genes are associated with high-grade CIN. In addition a comparison was also made between cases of high grade CIN derived from 30 patients infected with HPV 16/18 and 29 patients infected with non-16/18 HPV to determine if KIR variation contributes to the disproportional carcinogenesis derived from HPV 16/18 infection.ResultsHigh-grade CIN was weakly associated with the absence of KIR2DL2 and KIR2DS2 (p = 0.046 and 0.049 respectively, OR 0.6; 95% CI 0.4 – 0.9) but this association was lost after correction for multi-gene statistical analysis. No difference in KIR gene frequencies was found between high-grade CIN caused by HPV 16/18 and non-16/18.ConclusionNo strong association between KIR genes, high-grade CIN and HPV genotype was found in the Western Australian population.

KIR3DS1/L1 and HLA-Bw4-80I are associated with HIV disease progression among HIV typical progressors and long-term nonprogressors

BackgroundNatural killer (NK) cells have emerged as pivotal players in innate immunity, especially in the defense against viral infections and tumors. Killer immunoglobulin-like receptors (KIRs) – an important recognition receptor expressed on the surface of NK cells – regulate the inhibition and/or activation of NK cells after interacting with human leukocyte antigen (HLA) class I ligands. Various KIR genes might impact the prognosis of many different diseases. The implications of KIR-HLA interaction in HIV disease progression remains poorly understood.MethodsHere, we studied KIR genotypes, mRNA levels, HLA genotypes, CD4+ T cell counts and viral loads in our cohort of Human Immunodeficiency Virus (HIV)-infected individuals, a group that includes HIV long-term nonprogressors (LTNPs) and typical progressors (TPs).ResultsWe found that the frequency of KIR3DS1/L1 heterozygotes with HLA-Bw4-80I gene was much higher in LTNPs than in TPs (P = 0.001) and that the KIR3DL1 homozygotes without HLA-Bw4-80I gene had higher viral loads and lower CD4+ T cell counts (P = 0.014 and P = 0.021, respectively). Our study also confirmed that homozygosity for the HLA-Bw6 allele was associated with rapid disease progression. In addition to the aforementioned results on the DNA level, we observed that higher level expression of KIR3DS1 mRNA was in LTNP group, and that higher level expression of KIR3DL1 mRNA was in TP group.ConclusionsOur data suggest that different KIR-HLA genotypes and different levels of transcripts associate with HIV disease progression.

Killer Immunoglobulin-Like Receptor (KIR) Centromeric-AA Haplotype Is Associated with Ethnicity and Tuberculosis Disease in a Canadian First Nations Cohort

Killer immunoglobulin-like receptors (KIR) on natural killer (NK) cells interact with other immune cells to monitor the immune system and combat infectious diseases, such as tuberculosis (TB). The balance of activating and inhibiting KIR interactions helps determine the NK cell response. In order to examine the enrichment or depletion of KIRs as well as to explore the association between TB status and inhibitory/stimulatory KIR haplotypes, we performed KIR genotyping on samples from 93 Canadian First Nations (Dene, Cree, and Ojibwa) individuals from Manitoba with active, latent, or no TB infection, and 75 uninfected Caucasian controls. There were significant differences in KIR genes between Caucasians and First Nations samples and also between the First Nations ethnocultural groups (Dene, Cree, and Ojibwa). When analyzing ethnicity and tuberculosis status in the study population, it appears that the KIR profile and centromeric haplotype are more predictive than the presence or absence of individual genes. Specifically, the decreased presence of haplotype B centromeric genes and increased presence of centromeric-AA haplotypes in First Nations may contribute to an inhibitory immune profile, explaining the high rates of TB in this population.

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

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.

Extensive Variation in Gene Copy Number at the Killer Immunoglobulin-Like Receptor Locus in Humans

Killer immunoglobulin-like receptors (KIRs) are involved in the regulation of natural killer cell cytotoxicity. Within the human genome seventeen KIR genes are present, which all contain a large number of allelic variants. The high level of homology among KIR genes has hampered KIR genotyping in larger cohorts, and determination of gene copy number variation (CNV) has been difficult. We have designed a multiplex ligation-dependent probe amplification (MLPA) technique for genotyping and CNV determination in one single assay and validated the results by next-generation sequencing and with a KIR gene-specific short tandem repeat assay. In this way, we demonstrate in a cohort of 120 individuals a high level of CNV for all KIR genes except for the framework genes KIR3DL3 and KIR3DL2. Application of our MLPA assay in segregation analyses of families from the Centre d’Etude du Polymorphisme Humaine, previously KIR-genotyped by classical techniques, confirmed an earlier reported duplication and resulted in the identification of a novel duplication event in one of these families. In summary, our KIR MLPA assay allows rapid and accurate KIR genotyping and CNV detection, thus rendering improved transplantation programs and oncology treatment feasible, and enables more detailed studies on the role of KIRs in human (auto)immunity and infectious disease.

Distribution of Killer cell immunoglobulin like receptor genes in end stage renal disease among North Indian population

NK cell function is regulated by cell surface inhibitory and activating receptors including the C-type lectin receptors and Killer Immunoglobulin-like receptors (KIR). The effect of immune modulating cytokines produced by NK cells in the pathogenesis of end stage renal disease (ESRD) remained intriguing. In this regard the present study assesses the combinatorial association of KIR gene content and KIR receptor-HLA ligand in the North Indian ESRD patients. KIR gene polymorphism as a susceptible marker in ESRD among 512 patients and 512 ethnically matched controls was analyzed. PCR-SSP based genotyping for KIR gene content and HLA-A, B, C typing was carried out. Significant difference in frequencies of KIR2DS1-HLA-C2 (p≤0.0001, OR=1.98, CI=1.50-2.61), KIR2DS2-HLAC1 (p≤0.0001, OR=1.87, CI=1.42-2.46), KIR3DS1-HLA-Bw4 (p=0.0038, OR=1.46, CI=1.13-1.88) combinations for ESRD was found. In the combinatorial analysis Bw4(+)/3DL1(-)/3DS1(+) (p≤0.0001, OR=4.90, CI=2.75-8.71) and C1(+)/2DL2(-)/2DL3(-)/2DS2(+)/2DS3(+) (p=0.0037, OR=2.50, CI=1.35-4.63) showed risk association. KIR3DS1 was observed to be susceptible for all four primary kidney disease groups. NK cell de-regulation due to HLA ligand binding KIR receptors may be involved in the patho-physiology of ESRD. Upon analyzing the data in this context it was found that C2/C2 donor might improve the clinical outcome of patients having C2 ligands.

Absence of activating killer immunoglobulin-like receptor genes combined with hepatitis C viral genotype is predictive of hepatocellular carcinoma

Killer immunoglobulin-like receptors and their human leukocyte antigen class I ligands have a critical role in natural killer cell response to viral pathogens and tumors. To investigate whether killer immunoglobulin-like receptor genes could influence the chronic course of hepatitis C virus infection and/or progression to hepatocellular carcinoma we retrospectively analyzed a cohort of 228 patients transplanted for hepatitis C virus-induced cirrhotic end stage liver disease, combined or not with hepatocellular carcinoma. We found that patients completely lacking activating killer immunoglobulin-like receptor genes had a high risk of developing hepatocellular carcinoma. Hepatitis C viral genotype and viral load are other risk factors that can influence the course of chronic hepatitis C virus infection. In our study, the risk conferred by hepatitis C viral genotypes was enhanced in patients lacking activating killer immunoglobulin-like receptors. These results point to an important role for activating killer immunoglobulin-like receptors in the control of hepatitis C virus infection and progression to hepatocellular carcinoma. In clinical practice, assessment of killer immunoglobulin-like receptor and hepatitis C viral genotype combinations should allow for more accurate monitoring of patients with chronic hepatitis C virus infection.

KIR diversity in three ethnic populations of Assam state, Northeast India

Killer immunoglobulin-like receptors (KIR) exhibit extensive diversity and it has been observed that populations with different ethno-history, linguistic, geographic and genetic backgrounds can differ in KIR profile. In this context, we have investigated the KIR complex in three ethnic populations-Kachari (n = 108), Ahom (n = 104) and Adivasi (n = 101) of Assam, Northeast India. The three populations had 145 distinct KIR genotypes in 313 individuals typed. The two Mongoloid populations--Kachari and Ahom had close genetic affinities with their parental East Asian groups where the Kachari clustered with Chinese populations and the Ahom in another clade clustered with Thailand Bangkok and Polynesian populations. The Adivasi differed markedly from these Mongoloid populations in having higher KIR 2DL2, 2DS2, 2DS3 and 2DS5, but lower 2DL3 (P value <0.0001). Like the other native Indian populations, the Adivasi had higher share of Bx-haplogroup and C4Tx genotype (37/101). However, unlike other Indian populations, KIR 3DS1 gene frequency was lower in Adivasi (21%) and was comparable to the African populations. The neighbor-joining dendogram generated on the basis of KIR gene frequencies of our study populations with 43 world populations also placed the Adivasi with African populations. Interestingly, the three populations in the dendogram are consistent with their migration histories. In summary, our data suggest that KIR profile of the three ethnic populations displayed ethnic diversity and was consistent with their migration history thereby supporting the concept that KIR diversity may be used to understand genetic affinity and migration history of populations.

KIR Gene Mismatching and KIR/C Ligands in Liver Transplantation

Killer immunoglobulin-like receptors (KIRs) bind human leukocyte antigen (HLA) class-I (HLA-I) ligands and regulate functions of natural killer cells and subsets of T cells. KIR/HLA-I interactions allow predicting natural killer cell alloreactivity in hematopoietic stem cell transplantation and in HLA-compatible kidney transplants, but its meaning in liver transplantation remains controversial. KIR and HLA genotypes were studied in 402 liver transplants, using sequence-specific oligonucleotides and primer methods. Recipients and donor KIRs, HLA-C genotypes, KIR gene mismatches (MMs) between recipient-donor pairs, and KIR/HLA-ligand combinations were analyzed in overall transplantations, in the acute rejection (AR; n=110) and non-AR (n=292) groups. KIR gene MMs between recipients and donors, mainly in activating KIRs, and KIR2DL3 and KIR2DS1 of recipients in the presence of donor C2 ligands, significantly enhanced early AR rate (P<0.05), with KIR2DL3 and KIR2DS1 exhibiting a synergic effect in dependence of the donor C2 ligand number (χ2=7.662, P=0.022). KIR2DL3, KIR2DS1, and also KIR2DS4 significantly influenced short-term graft survival, with a benefit for transplantations combining KIR2DL3 recipients and donors having C1 ligands (log rank, P<0.019 at 1 year; hazards ratio [HR], 0.321; 95% confidence interval [CI], 0.107-0.962; P=0.042), whereas KIR2DS1 and KIR2DS4 recipients combined with donors lacking C1 ligands (C2/C2) exhibited a worse graft survival (log rank, P=0.035 at 6 months; HR, 7.713; 95% CI, 2.156-27.369; P=0.002 for KIR2DS1; and log rank, P=0.006 at 1 year; HR, 3.794; 95% CI, 1.267-11.365; P=0.017 for KIR2DS4). This study shows that KIR gene-gene MMs increase AR and that KIRs/C ligands associated to AR and KIR2DS4/C ligands also influence short-term graft survival.

Abstract 1332: Functional killer-immunoglobulin-like receptor variation and risk of non-melanoma skin cancer.

Abstract Natural killer (NK) cells of the immune system are the first line of defense against transformed and infected cells. NK cell action is determined through binding of killer immunoglobulin-like receptors (KIR) with specific human leukocyte antigen (HLA) class I ligands on target cells. The KIR gene family is diverse and highly polymorphic, is poorly covered on GWAS platforms, and exhibits significant functional copy number variation. The KIR locus has been primarily studied in the context of HCV, HIV, and transplant outcomes. Here, we have tested the hypothesis that KIR genotypes are associated with Non-Melanoma Skin Cancer (NMSC) etiology. These are among the most prevalent malignancies worldwide with rising incidence. In addition, they are highly antigenic tumors, with a possible viral etiology, making NMSC an ideal model to test KIR as a cancer susceptibility trait. A random subset of a population-based case-control study in New Hampshire was selected for the study: 422 basal cell carcinomas (BCC) (1 BCC=243, 2 BCC=131, ≥3 BCC=48), 132 squamous cell carcinomas (SCC), and 222 controls. KIR genotyping was performed with Lifecodes KIR-SSO typing kit on Luminex using buffy coat derived genomic DNA, capturing KIR loci: 2DS1, 2DS2, 2DS3, 2DS4, 2DS5, 2DP1, 2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 3DL1, 3DS1, and 3DL2. Cutaneous HPV status was assessed using serum samples and established Luminex detection assays covering 16 genus beta HPV types. The KIR2DL2/3 locus was associated with a significantly increased risk of BCC (OR=2.65, 95% CI: 1.08-6.48), which was particularly strong for cases with 3 or more tumors (OR=5.77, 95% CI: 1.30-25.66). For SCC, the KIR3DL1 gene was associated with a significantly increased risk of malignancy (OR=3.73, 95% CI: 1.51-9.22). Next we investigated the association of KIR and SCC within HPV strata. The KIR3DL1-SCC association was strongest among those with no evidence of HPV infection (OR=6.81, 95% CI: 1.78-26.12). In contrast, the non-functional KIR2DS4 variant related to an increased risk and the KIR2DL2 gene related to reduced risk of SCC among those with multiple β-HPV infections. Our results implicate a strong role for KIR in the etiology of NMSC. KIR2DL2/3 may be particularly important in the development of multiple BCC, and KIR3DL1 in the pathogenesis of SCC. Finally, we identified a pattern of KIR-SCC associations that supports a potential etiologic role of cutaneous HPV in SCC occurrence. Citation Format: Karin A. Vineretsky, Margaret R. Karagas, Michael Pawlita, Heather H. Nelson. Functional killer-immunoglobulin-like receptor variation and risk of non-melanoma skin cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1332. doi:10.1158/1538-7445.AM2013-1332

Homozygosity for killer immunoglobin-like receptor haplotype A predicts complete molecular response to treatment with tyrosine kinase inhibitors in chronic myeloid leukemia patients

Several recent reports suggest a possible role for killer immunoglobulin-like receptors (KIR) in the onset of chronic myeloid leukemia (CML) and response to therapy with tyrosine kinase inhibitors (TKIs). To explore this hypothesis, we studied KIRs and their human leukocyte antigen class I ligands in 59 consecutive patients with chronic-phase CML (mean age, 53 years; range, 23-81 years) and a group of 121 healthy control participants belonging to the same ethnic group as the patients. The 2-year cumulative incidence of complete molecular response, obtained after a median of 27 months (range, 4-52 months), was 51.2%. An increased frequency of the activating receptor KIR2DS1 (pm = 0.05) and a reduced frequency of the KIR-ligand combination KIR2DS2/2DL2 absent/C1 present (pm = 0.001) were significantly associated with CML. Moreover, KIR repertoires in patients appeared to influence response to TKI therapy. Homozygosity for KIR haplotype A (pm = 0.01), a decreased frequency of the inhibitory KIR gene KIR2DL2 (pm = 0.02), and low numbers of inhibitory KIR genes (pm = 0.05) were all significantly associated with achievement of complete molecular remission. These data suggest that a decrease in properly stimulated and activated NK cells might contribute to the occurrence of CML and indicate homozygosity for KIR haplotype A as a promising immunogenetic marker of complete molecular response that could help clinicians decide whether to withdraw treatment in patients with CML.

KIR gene variability in cutaneous malignant melanoma: influence of KIR2D/HLA-C pairings on disease susceptibility and prognosis

Natural killer and CD8(+) T cells are believed to be involved in the immune protection against melanoma. Their function may be regulated by a group of receptors defined as killer immunoglobulin-like receptors (KIRs) and their cognate HLA class I ligands. In this study, we analyzed the influence of KIR genes and KIR/HLA-I combinations on melanoma susceptibility and/or prognosis in a Spanish Caucasian population. For this purpose, KIR genotyping by PCR-SSP and HLA-C genotyping by reverse PCR-SSO were performed in 187 melanoma patients and 200 matched controls. We found a significantly low frequency of KIR2DL3 in nodular melanoma (NM) patients (P = 0.001) and in ulcerated melanoma patients (P < 0.0001). Similarly, the KIR2DL3/C1 combination was significantly decreased in melanoma patients (Pc = 0.008) and in patients with sentinel lymph node (SLN) melanoma metastasis (Pc = 0.002). Multivariate logistic regression models showed that KIR2DL3 behaves as a protective marker for NM and ulcerated melanoma (P = 0.02, odds ratio (OR) = 0.14 and P = 0.04, OR = 0.28, respectively), whereas the KIR2DL3/C1 pair acts as a protective marker for melanoma (P = 0.017, OR = 0.54), particularly superficial spreading melanoma (P = 0.02, OR = 0.52), and SLN metastasis (P = 0.0004, OR = 0.14). In contrast, the KIR2DL3(-)/C1C2 genotype seems to be correlated with NM and ulceration. We also report that the KIR2DL1(+)/S1(-)/C2C2 genotype is associated with susceptibility to melanoma and SLN metastasis. Altogether, the study of KIR2D genes and HLA-C ligands may help in assessing cutaneous melanoma risk and prognosis.