Impact of "Killer Immunoglobulin-Like Receptor /Ligand" Genotypes on Outcome following Surgery among Patients with Colorectal Cancer: Activating KIRs Are Associated with Long-Term Disease Free Survival

Phase I study of safety and efficacy of allogeneic natural killer cell therapy in relapsed/refractory neuroblastomas post autologous hematopoietic stem cell transplantation

Despite low incidence, neuroblastoma, an immunologically cold tumor, is the most common extracranial solid neoplasm in pediatrics. In relapsed/refractory cases, the benefits of autologous hematopoietic stem cell transplantation (auto-HSCT) and other therapies are limited. Natural killer (NK) cells apply cytotoxicity against tumor cells independently of antigen-presenting cells and the adaptive immune system. The primary endpoint of this trial was to assess the safety of the injection of allogenic, ex vivo-expanded and primed NK cells in relapsed/refractory neuroblastoma patients after auto-HSCT. The secondary endpoint included the efficacy of this intervention in controlling tumors. NK cells were isolated and primed ex vivo (by adding interleukin [IL]-2, IL-15, and IL-21) in a GMP-compliant CliniMACS system and administered to four patients with relapsed/refractory MYCN-positive neuroblastoma. NK cell injections (1 and 5 × 107 cells/kg in the first and second injections, respectively) were safe, and no acute or sub-acute adverse events were observed. During the follow-up period, one complete response (CR) and one partial response (PR) were observed, while two cases exhibited progressive disease (PD). In follow-up evaluations, two died due to disease progression, including the case with a PR. The patient with CR had regular growth at the 31-month follow-up, and another patient with PD is still alive and receiving chemotherapies 20 months after therapy. This therapy is an appealing and feasible approach for managing refractory neuroblastomas post-HSCT. Further studies are needed to explore its efficacy with higher doses and more frequent administrations for high-risk neuroblastomas and other immunologically cold tumors.Trial registration number: irct.behdasht.gov.ir (Iranian Registry of Clinical Trials, No. IRCT20201202049568N1).

KIR2DS2+ NK cells in cancer patients demonstrate high activation in response to tumour-targeting antibodies

Strategies to mobilise natural killer (NK) cells against cancer include tumour-targeting antibodies, NK cell engagers (NKCEs) and the adoptive transfer of ex vivo expanded healthy donor-derived NK cells. Genetic and functional studies have revealed that expression of the activating killer immunoglobulin-like receptor KIR2DS2 is associated with enhanced function in NK cells from healthy donors and improved outcome in several different malignancies. The optimal strategy to leverage KIR2DS2+ NK cells therapeutically is however currently unclear. In this study, we therefore evaluated the response of KIR2DS2-expressing NK cells to activation against cancer with clinically relevant tumour-targeting antibodies and following ex vivo expansion. We identified that KIR2DS2high NK cells from patients with chronic lymphocytic leukaemia and hepatocellular carcinoma had enhanced activation in response to tumour-targeting antibodies compared to KIR2DS2- NK cells. However, the superior function of healthy donor derived KIR2DS2high NK cells was lost following ex vivo expansion which is required for adoptive transfer-based therapeutic strategies. These data provide evidence that targeting KIR2DS2 directly in cancer patients may allow for the utilisation of their enhanced effector function, however such activity may be lost following their ex vivo expansion.

The nuclear export protein XPO1 provides a peptide ligand for natural killer cells

XPO1 (Exportin-1/CRM1) is a nuclear export protein that is frequently overexpressed in cancer and functions as a driver of oncogenesis. Currently small molecules that target XPO1 are being used in the clinic as anticancer agents. We identify XPO1 as a target for natural killer (NK) cells. Using immunopeptidomics, we have identified a peptide derived from XPO1 that can be recognized by the activating NK cell receptor KIR2DS2 in the context of human leukocyte antigen-C. The peptide can be endogenously processed and presented to activate NK cells specifically through this receptor. Although high XPO1 expression in cancer is commonly associated with a poor prognosis, we show that the outcome of specific cancers, such as hepatocellular carcinoma, can be substantially improved if there is concomitant evidence of NK cell infiltration. We thus identify XPO1 as a bona fide tumor antigen recognized by NK cells that offers an opportunity for a personalized approach to NK cell therapy for solid tumors.

The KIR2DL family serves as prognostic biomarkers and correlates with immune infiltrates in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a prevalent haematological malignancy in which various immune and stromal cells in the bone marrow microenvironment have instrumental roles and substantially influence its progression. KIR2DL is a member of the immunoglobulin-like receptor family and a natural killer (NK) cell surface-specific receptor. However, its impact on immune infiltration regarding AML has not been addressed. We aimed to explore molecular markers associated with the immune microenvironment and prognosis of AML with a particular focus on KIR2DL family members. Analysis of data from The Cancer Genome Atlas and Genotype-Tissue Expression databases revealed that KIR2DL1, KIR2DL3 and KIR2DL4 expression were significantly upregulated in AML and associated with decreased overall survival (OS). Moreover, univariate Cox analysis implicated KIR2DL genes as independent prognostic markers of OS. Functional enrichment analysis revealed that KIR2DL genes were associated with immune cells, the immune microenvironment and NK cell-mediated cytotoxicity. Additionally, immune infiltration analyses revealed that KIR2DL upregulation was associated with stronger immune infiltration. Finally, we performed drug sensitivity profiling of KIR2DL genes using the Cellminer database. Collectively, our findings suggest that KIR2DL1, KIR2DL3 and KIR2DL4 have critical roles in AML and may represent novel biomarker genes for disease prognosis and immune infiltration.

A Novel Hypothesis: Certain KIR/Cognate Ligand Containing Genotypes Differ in Frequency Among Patients With Myeloma and Have an Effect on Age of Disease Onset

BACKGROUND

Natural killer (NK) cells are known to have cytotoxic effects mediated through killer immunoglobulin-like receptors (KIRs) and their cognate ligands. Role of KIRs in myeloma is yet unresolved.

PATIENTS AND METHODS

KIR genotypes and ligands of 204 newly diagnosed MM patients are compared with 424 healthy subjects. Statistical analysis included t-test, chi-square and binary logistic regression.

RESULTS

KIR ligands were significantly more (C2C2: 27.5% vs 15.1%; OR 2.128; 95% CI, 1.417-3.196; P < .001) or less (C1C2: 40.2% vs 51.9%; OR 0.623; 95% CI, 0.444-0.874; P = .006) frequent among MM. Co-occurrence of genotype AA with C2C2 was also higher in frequency among MM (OR 2.509; 95% CI, 1.171-5.378; P = .015) likewise cAB1 with C1C2 was less frequent (OR 0.553; 95% CI, 0.333-0.919; P = .021). Genotypes AA with C1C1, cAB1 with C1C2 or C1C2 alone were associated with a delay (median age: 61 [48-73]; P = .044; 62 [31-81]; P = .030 or 59 [31-85]; P = .028), but AA with C2C2 with an earlier age of onset (48 [29-77]; P = .042). In multivariate analysis including R-ISS, light chain, KIR genotype/ligands; ligand C1C2 (P = .02) and genotype AA-C1C1 (P = .037) were independently associated with age of onset ≥60.

CONCLUSION

C1C2 and C2C2 alone or in combination with KIR genotype (cAB1 and AA, respectively), is observed in less or higher frequency among MM cases and associated with delayed/earlier age of onset, respectively. Genotype AA-C1C1 although in similar frequency between patients and healthy subjects, is also associated with delay. To our knowledge, this is the first study demonstrating an association between KIR and MM onset age, independent from R-ISS or light chain type.

NK Cells and Other Cytotoxic Innate Lymphocytes in Colorectal Cancer Progression and Metastasis

Colorectal cancer (CRC) is one of the most common malignancies and leading causes of cancer-related deaths worldwide. Despite its complex pathogenesis and progression, CRC represents a well-fitting example of how the immune contexture can dictate the disease outcome. The presence of cytotoxic lymphocytes, both CD8⁺ T cells and natural killer (NK) cells, represents a relevant prognostic factor in CRC and is associated with a better overall survival. Together with NK cells, other innate lymphocytes, namely, innate lymphoid cells (ILCs), have been found both in biopsies of CRC patients and in murine models of intestinal cancer, playing both pro- and anti-tumor activities. In particular, several type 1 innate lymphoid cells (ILC1) with cytotoxic functions have been recently described, and evidence in mice shows a role for both NK cells and ILC1 in controlling CRC metastasis. In this review, we provide an overview of the features of NK cells and the expanding spectrum of innate lymphocytes with cytotoxic functions. We also comment on both the described and the potential roles these innate lymphocytes can play during the progression of intestinal cancer leading to metastasis. Finally, we discuss recent advances in the molecular mechanisms underlying the functional regulation of cytotoxic innate lymphocytes in CRC.

KIR2DS2 Expression Identifies NK Cells With Enhanced Anticancer Activity

NK cells are promising cellular therapeutics against hematological and solid malignancies. Immunogenetic studies have identified that various activating killer cell Ig-like receptors (KIRs) are associated with cancer outcomes. Specifically, KIR2DS2 has been associated with reduced incidence of relapse following transplant in hematological malignancies and improved outcomes in solid tumors, but the mechanism remains obscure. Therefore, we investigated how KIR2DS2 expression impacts NK cell function. Using a novel flow cytometry panel, we show that human NK cells with high KIR2DS2 expression have enhanced spontaneous activation against malignant B cell lines, liver cancer cell lines, and primary chronic lymphocytic leukemia cells. Surface expression of CD16 was increased on KIR2DS2high NK cells, and, accordingly, KIR2DS2high NK cells had increased activation against lymphoma cells coated with the clinically relevant anti-CD20 Abs rituximab and obinutuzumab. Bulk RNA sequencing revealed that KIR2DS2high NK cells have upregulation of NK-mediated cytotoxicity, translation, and FCGR gene pathways. We developed a novel single-cell RNA-sequencing technique to identify KIR2DS2+ NK cells, and this confirmed that KIR2DS2 is associated with enhanced NK cell-mediated cytotoxicity. This study provides evidence that KIR2DS2 marks a population of NK cells primed for anticancer activity and indicates that KIR2DS2 is an attractive target for NK-based therapeutic strategies.

A model integrating Killer Immunoglobulin-like Receptor (KIR) haplotypes for risk prediction of COVID-19 clinical disease severity

Associations between inherited Killer Immunoglobulin-like Receptor (KIR) genotypes and the severity of multiple RNA virus infections have been reported. This prospective study was initiated to investigate if such an association exists for COVID-19. In this cohort study performed at Ankara University, 132 COVID-19 patients (56 asymptomatic, 51 mild-intermediate, and 25 patients with severe disease) were genotyped for KIR and ligands. Ankara University Donor Registry (n:449) KIR data was used for comparison. Clinical parameters (age, gender, comorbidities, blood group antigens, inflammation biomarkers) and KIR genotypes across cohorts of asymptomatic, mild-intermediate, or severe disease were compared to construct a risk prediction model based on multivariate binary logistic regression analysis with backward elimination method. Age, blood group, number of comorbidities, CRP, D-dimer, and telomeric and centromeric KIR genotypes (tAA, tAB1, and cAB1) along with their cognate ligands were found to differ between cohorts. Two prediction models were constructed; both included age, number of comorbidities, and blood group. Inclusion of the KIR genotypes in the second prediction model exp (-3.52 + 1.56 age group - 2.74 blood group (type A vs others) + 1.26 number of comorbidities - 2.46 tAB1 with ligand + 3.17 tAA with ligand) increased the predictive performance with a 92.9% correct classification for asymptomatic and 76% for severe cases (AUC: 0.93; P < 0.0001, 95% CI 0.88, 0.99). This novel risk model, consisting of KIR genotypes with their cognate ligands, and clinical parameters but excluding earlier published inflammation-related biomarkers allow for the prediction of the severity of COVID-19 infection prior to the onset of infection. This study is listed in the National COVID-19 clinical research studies database.

Peptide: MHC-based DNA vaccination strategy to activate natural killer cells by targeting killer cell immunoglobulin-like receptors

BACKGROUND

Natural killer (NK) cells are increasingly being recognized as agents for cancer immunotherapy. The killer cell immunoglobulin-like receptors (KIRs) are expressed by NK cells and are immunogenetic determinants of the outcome of cancer. In particular, KIR2DS2 is associated with protective responses to several cancers and also direct recognition of cancer targets in vitro. Due to the high homology between activating and inhibitory KIR genes to date, it has been challenging to target individual KIR for therapeutic benefit.

METHODS

A novel KIR2DS2-targeting therapeutic peptide:MHC DNA vaccine was designed and used to immunize mice transgenic for KIR genes (KIR-Tg). NK cells were isolated from the livers and spleens of vaccinated mice and then analyzed for activation by flow cytometry, RNA profiling and cytotoxicity assays. In vivo assays of NK cell function using a syngeneic cancer model (B16 melanoma) and an adoptive transfer model for human hepatocellular carcinoma (Huh7) were performed.

RESULTS

Injecting KIR-Tg mice with the vaccine construct activated NK cells in both liver and spleens of mice, with preferential activation of KIR2DS2-positive NK cells. KIR-specific activation was most marked on the CD11b+CD27+ mature subset of NK cells. RNA profiling indicated that the DNA vaccine upregulated genes associated with cellular metabolism and downregulated genes related to histone H3 methylation, which are associated with immune cell maturation and NK cell function. Vaccination led to canonical and cross-reactive peptide:MHC-specific NK cell responses. In vivo, DNA vaccination led to enhanced antitumor responses against B16F10 melanoma cells and also enhanced responses against a tumor model expressing the KIR2DS2 ligand HLA-C*0102.

CONCLUSION

We show the feasibility of a peptide-based KIR-targeting vaccine strategy to activate NK cells and hence generate functional antitumor responses. This approach does not require detailed knowledge of the tumor peptidomes nor HLA matching with the patient. It therefore offers a novel opportunity for targeting NK cells for cancer immunotherapy.

Killer immunoglobulin-like receptors/human leukocyte antigen class-I, a crucial immune pathway in cancer

Natural killer cells (NK cells) play a crucial role in tumor immunity. The function of the NK cells is regulated by various receptors expressed on the surface. Among them, the killer immunoglobulin-like receptor (KIR) is one of the most important. The ligand of KIR is major histocompatibility complex class-I (MHC class-I), which is also called human leukocyte antigen class-I (HLA class-I). The combination of HLA class-I and inhibitory KIRs could inhibit NK cells and induce autoimmune tolerance. Inhibitory KIRs were highly expressed on malignant tumor patients, which were related to poor prognosis. KIR/HLA class-I pathway affected the clinical outcomes of cancer through several mechanisms, and inhibitory KIRs could be an ideal target of immunotherapy strategy.

Analysis of Killer Immunoglobulin-Like Receptor Genes in Colorectal Cancer

Natural killer cells (NK cells) play a major role in the immune response to cancer. An important element of NK target recognition is the binding of human leucocyte antigen (HLA) class I molecules by killer immunoglobulin-like receptors (KIRs). Colorectal carcinoma (CRC) is one of the most common types of inflammation-based cancer. The purpose of the present study was to investigate the presence of KIR genes and HLA class I and II alleles in 1074 CRC patients and 1272 controls. We imputed data from single-nucleotide polymorphism (SNP) Illumina OncoArray to identify associations at HLA (HLA–A, B, C, DPB1, DQA1, DQB1, and DRB1) and KIRs (HIBAG and KIR*IMP, respectively). For association analysis, we used PLINK (v1.9), the PyHLA software, and R version 3.4.0. Only three SNP markers showed suggestive associations (p < 10⁻³; rs16896742, rs28367832, and rs9277952). The frequency of KIR2DS3 was significantly increased in the CRC patients compared to healthy controls (p < 0.005). Our results suggest that the implication of NK cells in CRC may not act through allele combinations in KIR and HLA genes. Much larger studies in ethnically homogeneous populations are needed to rule out the possible role of allelic combinations in KIR and HLA genes in CRC risk.

Killer Immunoglobulin-Like Receptor-Ligand Interactions Predict Clinical Outcomes following Unrelated Donor Transplantations

Killer immunoglobulin-like receptor (KIR) and KIR ligand (KIRL) interactions play an important role in natural killer (NK) cell-mediated graft-versus-leukemia effect following hematopoietic cell transplantation (HCT). However, there is considerable heterogeneity in the KIR gene and KIRL content in individuals, making it difficult to estimate the full clinical impact of NK cell reconstitution following HCT. Here we present a novel adaptive mathematical model designed to quantify these interactions to better assess the influence of NK cell-mediated alloreactivity on transplant outcomes. Ninety-eight HLA- matched unrelated donor (URD) HCT recipients were studied retrospectively. The KIR-KIRL interactions were quantified using a system of matrix equations. Unit values were ascribed to each KIR-KIRL interaction, and the directionality of interactions was denoted by either a positive (activating) or negative (inhibition) symbol; these interactions were then summed. The absolute values of both the missing KIRL and inhibitory KIR-KIRL interactions were significantly associated with overall survival and relapse. These score components were initially used to develop a weighted score (w-KIR score) and subsequently a simplified, nonweighted KIR-KIRL interaction score (IM-KIR score). Increased w-KIR score and IM-KIR score were predictive of all-cause mortality and relapse (w-KIR score: hazard ratio [HR], .37 [P = .001] and .44 [P = .044], respectively; IM-KIR score: HR, .5 [P = .049] and .44 [P = .002], respectively). IM-KIR score was also associated with NK cell reconstitution post-HCT. KIR-KIRL interactions as reflected by the w-KIR and IM-KIR scores influence both relapse risk and survival in recipients of HLA-matched URD HCT with hematologic malignancies.

Activating and inhibitory killer cell immunoglobulin like receptors (KIR) genes are involved in an increased susceptibility to colorectal adenocarcinoma and protection against invasion and metastasis

BACKGROUND

A set of activating and inhibitory KIRs (aKIR, iKIR) are involved in NK cell mediated immunity. This study was carried out in order to investigate the KIRs pattern and its association with colorectal carcinoma (CRC) development and clinical outcomes.

METHODS

Sequence-specific primers-polymerase chain reaction (SSP-PCR) for typing of 16 KIR genes was utilized in 165 patients with colorectal adenocarcinoma with 165 age and gender matched healthy controls (CNs).

RESULTS

Possessing KIR2DS1, 2DS5, 3DS1, 2DS4fl, 2DL5, telomeric half KIR genes, ≥ 4 aKIR and CXT4 genotype were associated with an increased susceptibility to colorectal adenocarcinoma while KIR2DS4del and iKIR >aKIR confer resistance to CRC. On the other hand, clinical associations revealed the defensive role of telomeric KIR3DL1, 3DS1, 2DS1, 2DS4, genotypes with ≥ 4 aKIR and more inhibitory KIRs than activating ones (I > A) against metastasis and CXTX genotype in perineural invasion.

CONCLUSION

According to current results it appears that KIRs system play distinctive roles in development and metastasis of colorectal adenocarcinoma.

Beyond PD-1/PD-L1 Inhibition: What the Future Holds for Breast Cancer Immunotherapy

Cancer immunotherapy has altered the management of human malignancies, improving outcomes in an expanding list of diseases. Breast cancer - presumably due to its perceived low immunogenicity - is a late addition to this list. Furthermore, most of the focus has been on the triple negative subtype because of its higher tumor mutational load and lymphocyte-enriched stroma, although emerging data show promise on the other breast cancer subtypes as well. To this point the clinical use of immunotherapy is limited to the inhibition of two immune checkpoints, Programmed Cell Death Protein 1 (PD-1) and Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4). Consistent with the complexity of the regulation of the tumor - host interactions and their lack of reliance on a single regulatory pathway, combinatory approaches have shown improved efficacy albeit at the cost of increased toxicity. Beyond those two checkpoints though, a large number of co-stimulatory or co-inhibitory molecules play major roles on tumor evasion from immunosurveillance. These molecules likely represent future targets of immunotherapy provided that the promise shown in early data is translated into improved patient survival in randomized trials. The biological role, prognostic and predictive implications regarding breast cancer and early clinical efforts on exploiting these immune-related therapeutic targets are herein reviewed.

Emerging targets in cancer immunotherapy

The first generation of immune checkpoint inhibitors (anti-CTLA-4 and anti-PD-1/PD-L1) targeted natural immune homeostasis pathways, co-opted by cancers, to drive anti-tumor immune responses. These agents led to unprecedented results in patients with previously incurable metastatic disease and may become first-line therapies for some advanced cancers. However, these agents are efficacious in only a minority of patients. Newer strategies are becoming available that target additional immunomodulatory mechanisms to activate patients' own anti-tumor immune responses. Herein, we present a succinct summary of emerging immune targets with reported pre-clinical efficacy that have progressed to active investigation in clinical trials. These emerging targets include co-inhibitory and co-stimulatory markers of the innate and adaptive immune system. In this review, we discuss: 1) T lymphocyte markers: Lymphocyte Activation Gene 3 [LAG-3], T-cell Immunoglobulin- and Mucin-domain-containing molecule 3 [TIM-3], V-domain containing Ig Suppressor of T cell Activation [VISTA], T cell ImmunoGlobulin and ITIM domain [TIGIT], B7-H3, Inducible T-cell Co-stimulator [ICOS/ICOS-L], CD27/CD70, and Glucocorticoid-Induced TNF Receptor [GITR]; 2) macrophage markers: CD47/Signal-Regulatory Protein alpha [SIRPα] and Indoleamine-2,3-Dioxygenase [IDO]; and 3) natural killer cell markers: CD94/NKG2A and the Killer Immunoglobulin-like receptor [KIR] family. Finally, we briefly highlight combination strategies and potential biomarkers of response and resistance to these cancer immunotherapies.

Cancer treatment and the KIR-HLA system: an overview

Accumulating evidence indicates that the success of cancer therapy depends not only on a combination of adequate procedures (surgery, chemotherapy and radiotherapy) that aim to eliminate all tumor cells, but also on the functional state of the host immune system. HLA and KIR molecules, in particular, are critical to the interactions between tumor cells and both innate and adaptive immune cells such as NK cells and T cells. Different KIR-HLA gene combinations as well as different HLA expression levels on tumor cells associate with variable tumor prognosis and response to treatment. On the other hand, different therapies have different effects on HLA molecules and immune cell functions regulated by these molecules. Here, we provide an overview of the KIR-HLA system, a description of its alterations with clinical relevance in diverse tumor types, and an analysis of the consequences that conventional cancer therapies may have on it. We also discuss how this knowledge can be exploited to identify potential immunological biomarkers that can help to select patients for tailored therapy.

Targeting immune checkpoints in malignant glioma

Malignant glioma is the most common and a highly aggressive cancer in the central nervous system (CNS). Cancer immunotherapy, strategies to boost the body's anti-cancer immune responses instead of directly targeting tumor cells, recently achieved great success in treating several human solid tumors. Although once considered "immune privileged" and devoid of normal immunological functions, CNS is now considered a promising target for cancer immunotherapy, featuring the recent progresses in neurobiology and neuroimmunology and a highly immunosuppressive state in malignant glioma. In this review, we focus on immune checkpoint inhibitors, specifically, antagonizing monoclonal antibodies for programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), and indoleamine 2,3-dioxygenase (IDO). We discuss advances in the working mechanisms of these immune checkpoint molecules, their status in malignant glioma, and current preclinical and clinical trials targeting these molecules in malignant glioma.

Colorectal cancer and the KIR genes in the human genome: A meta-analysis

Colorectal cancer is one of the most common types of inflammation-based cancers and is occurred due to growth and spread of cancer cells in colon and/or rectum. Previously genetic association of cell cycle genes, both proto-oncogenes and the tumor suppressors has been proved. But there were few studies about association of immune related genes such as killer-cell immunoglobulin-like receptors (KIRs). Thus we intend to perform a meta-analysis to find the association of different genes of KIR and susceptibility to be affected by colorectal cancer. The overall population of the four studies investigated in our meta-analysis was 953 individuals (470 individuals with colorectal cancer and 483 individuals in control groups). After the analyses, we concluded that colorectal cancer is affected by KIR2DS5 and also there were no protecting gene. This result shows the inflammatory basis of this cancer. In other words, in contrast to leukemia and blood cancers, colorectal cancers seem to be affected by hyper activity of natural killer-cells (NKs). Whys and therefore of this paradox, is suggested to be investigated further.

Role of KIR and CD16A genotypes in colorectal carcinoma genetic risk and clinical stage

Background

NK cell cytotoxicity is regulated by the types of the interaction between killer immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I ligands on target cells and the different binding affinity of the Fcγ receptor IIIA (CD16A) for IgG-coated tumor cells. Thus, it is conceivable that KIR and CD16A gene contents may contribute to the function of NK cells by modulating an immune response in the colorectal carcinoma (CRC) microenvironment. This hypothesis is supported by recent evidence suggesting that NK cells improve the clinical course of CRC patients by enhancing the anti-CRC effect of CD8 + T cells. This information provides the rationale to test the hypothesis whether the independent KIR segregation and specificity, as well as CD16A gene polymorphisms, have an impact on CRC.

Methods

Using polymerase chain reaction-sequence-specific primers (PCR-SSP) and sequence-based typing (SBT), we investigated KIR/HLA-C complex and CD16A (48H/R/L,158V/F) gene polymorphisms in 52 CRC patients and 61 local healthy controls (LCTRs).

Results

The allele frequency (AF) of at least five activating KIR (aKIRs) of the B haplotype (p = 0.036, OR 0.204), KIR2DL2 (p = 0.047, OR 0.2616), and KIR2DS2 genes (5.8 vs LCTR 13.8 % and vs. Fasano’s CTR 16.3 %, p = 0.05, OR 0.3145), in the absence of their cognate HLA-C1 ligands, were significantly associated with a reduced genetic risk of CRC. In contrast, CD16A-48H polymorphism was positively associated with an increased genetic risk of CRC (p = 0.05, OR 2.761). The latter was also found to be correlated with advanced stages of disease [III and IV (p = 0.03, OR 3.625)].

Conclusions

Our data suggest that the analysis of aKIRs and KIR2DL2 gene and CD16A-48H may be of interest for the identification of individuals at reduced and increased genetic risk of CRC, respectively.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1001-y) contains supplementary material, which is available to authorized users.