Positive association of Bx genotype, KIR2L5, KIR2DS5 and full-length KIR2DS4 with the risk of meningioma

The effects of killer cell immunoglobulin-like receptor (KIR) genes on susceptibility to severe COVID-19 in the Iranian population

BACKGROUND

Variations in the innate and adaptive immune response systems are linked to variations in the severity of COVID-19. Natural killer cell (NK) function is regulated by sophisticated receptor system including Killer-cell immunoglobulin-like receptor (KIR) family. We aimed to investigate the impact of possessing certain KIR genes and genotypes on COVID19 severity in Iranians. KIR genotyping was performed on 394 age/sex matched Iranians with no underlying conditions who developed mild and severe COVID- 19. The presence and/or absence of 11 KIR genes were determined using the PCR with sequence specific primers (PCR-SSP).

RESULTS

Patients with mild symptoms had higher frequency ofKIR2DS1 (p = 0.004) and KIR2DS2 (p = 0.017) genes compared to those with severe disease. While KIR3DL3 and deleted variant of KIR2DS4 occurred more frequently in patients who developed a severe form of the disease. In this study, a significant increase of and B haplotype was observed in the Mild group compared to the Severe group (respectively, p = 0.002 and p = 0.02). Also, the prevalence of haplotype A was significantly higher in the Severe group than in the Mild group (p = 0.02).

CONCLUSIONS

These results suggest that the KIR2DS1, KIR2DS, and B haplotype maybe have a protective effect against COVID-19 severity. The results also suggest the inhibitory gene KIR2DL3 and haplotype A are risk factors for the severity of COVID-19.

Evaluation of the genetic diversity of KIR genes in patients with endometrial cancer

Endometrial cancer (EC) constitutes more than half of all genital cancers in women, with an increasing incidence in different countries. Natural killer cells (NK cells) are kinds of innate immune cells that are controlled by sets of receptors, such as killer cell Ig-like receptors (KIRs), which can inhibit or activate NK cells. In this study, we evaluated the diversity and genetic association of KIRs in confirmed cases of endometrial cancer compared to healthy controls. A total of 151 women with EC and 167 age/race-matched healthy controls were analyzed for KIR genes. Demographic and histopathologic data were gathered in questionnaires, and 16 KIR genes along with two variants of KIR2DS4 (KIR2DS4fl and KIR2DS4del), were genotyped by usingsequence specific primers-polymerase chain reaction (SSP-PCR) method. A comparison between cases and controls revealed that although there were not any significant differences in A haplotype associated genes and also the variants of KIR2DS4 (p >0.05), B haplotype associated genes such as KIR2DS2 and KIR2DL2 decreased significantly in EC patients in comparison with healthy controls (p=0.03 and p=0.01, respectively). Furthermore, we found that EC mostly developed in cases with the AA genotype; however, the carriers of Bx and C4T4 genotypes were less frequent in patients with EC. Our results revealed that KIR2DS2 and KIR2DL2, along with Bx and C4T4 genotypes, have a protective impact against developing endometrial cancer in Iranians.

The impact of killer cell immunoglobulin-like receptor (KIR) genes and human leukocyte antigen (HLA) class I ligands on predisposition or protection against prostate cancer

Natural killer (NK) cell development largely depends on killer cell immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I ligands. In the current study, we investigated the role of KIR genes, HLA ligands, and KIR-HLA combinations in vulnerability or protection against prostate cancer (PC). To analyze the frequency of 16 KIR genes and 5 HLA ligands, polymerase chain reaction with sequence-specific primers (PCR-SSP) was conducted in 150 PC patients and 200 healthy controls (CNs). KIR2DL5 (p = 0.0346, OR = 0.606, CI = 0.3916-0.9336), KIR2DS5 (p = 0.0227, OR = 0.587, CI = 0.3793-0.9139), HLA-B Bw4^Thr80 (p = 0.0401, OR = 0.3552, CI = 0.1466-0.9059), HLA Bw4 (p = 0.0190, OR = 0.4744, CI = 0.2656-0.8521), and T4 gene cluster (including KIR2DS5-2DL5-3DS1-2DS1 genes) (p = 0.0194, OR = 0.5575, CI = 0.3449-0.8938) had a lower frequency in the PC patients compared to the control group. Moreover, a lower frequency of the genotypes contacting activating KIR (aKIR) > inhibitory KIR (iKIR) (p = 0.0298, OR = 0.5291, CI = 0.3056-0.9174) and iKIR + HLA < aKIR + HLA (p = 0.0183, OR = 0.2197, CI = 0.0672-0.7001) in PC patients compared to the CNs implies a protective role for aKIR genes. In the case of KIR-HLA interactions, we detected a significant association between KIR3DS1⁺ + HLA-A Bw4⁺ (p = 0.0113, OR = 0.5093, CI = 0.3124-0.8416) and KIR3DL1^- + HLA-A Bw4⁺ (p = 0.0306, OR = 0.1153, CI = 0.0106-0.6537) combinations and resistance to prostate cancer. In contrast, the presence of KIR3DL1 in the absence of HLA-A Bw4 (p = 0.0040, OR = 2.00, CI = 1.264-3.111), HLA Bw4 (p = 0.0296, OR = 2.066, CI = 1.094-3.906), and HLA-Bw4^Thr80 (p = 0.0071, OR = 2.505, CI = 1.319-4.703) genes probably predisposes to prostate cancer. Carrying the CxT4 genotype in PC patients was positively associated with lower tumor grades (Gleason score ≤ 6) (p = 0.0331, OR = 3.290, and CI = 1.181-8.395). Altogether, our data suggest a protective role for aKIRs, HLA-B Bw4^Thr80, and HLA Bw4 ligands as well as a predisposing role for certain KIR-HLA combinations in prostate cancer. The findings of this study offer new insight into the population's risk assessment for prostate cancer in men. Additionally, predicting immunotherapy response based on KIR-HLA combinations aids in implementing the most effective therapeutic approach in the early stages of the disease.

Killer cell immunoglobulin-like receptor (KIR) gene contents: Are they associated with cervical cancer?

Killer cell immunoglobulin-like receptors (KIRs) are required for natural killer cell function against virus-infected cells or tumor cells. KIR gene content polymorphisms in Indian women with cervical cancer (CaCx) remain unexplored. Hence, we analyzed the frequencies of KIR genes, KIR haplotypes, and Bx subsets to draw their association with CaCx. The polymerase chain reaction-sequence-specific primer method was used for KIR genotyping in three groups of women: healthy controls (n = 114), women with human papillomavirus (HPV) infection (n = 70), and women with CaCx (n = 120). The results showed that the frequency of KIR2DS5 was significantly higher in women with CaCx compared to women with HPV infection (p = 0.02) and healthy controls (p = 0.01). Whereas the frequency of KIR2DL5B was significantly higher in healthy controls than in women with HPV infection (p = 0.02). The total number of activating KIR genes was higher in women with CaCx than in healthy controls (p = 0.006), indicating their positive association with CaCx. Moreover, the C4T4 subset was higher in women with CaCx than in women with HPV infection, though not significant. In conclusion, our findings highlight KIR2DS5, the C4T4 subset, and activating KIR genes are susceptible factors or positively associated with CaCx. Besides KIR2DL5B, this study also reported for the first time significantly high frequency of KIR2DL1 in healthy controls, indicating its possible protective association against CaCx. Further, significantly high frequency of KIR2DL3 observed in HPV-infected women might be also a promising biomarker for viral infections. Thus, the study confirms the association of KIR genes with cervical cancer in women with HPV infection.

KIR-HLA gene diversities and susceptibility to lung cancer

Killer-cell immunoglobulin-like receptors (KIR) are essential for acquiring natural killer (NK) cell effector function, which is modulated by a balance between the net input of signals derived from inhibitory and activating receptors through engagement by human leukocyte antigen (HLA) class I ligands. KIR and HLA loci are polygenic and polymorphic and exhibit substantial variation between individuals and populations. We attempted to investigate the contribution of KIR complex and HLA class I ligands to the genetic predisposition to lung cancer in the native population of southern Iran. We genotyped 16 KIR genes for a total of 232 patients with lung cancer and 448 healthy controls (HC), among which 85 patients and 178 HCs were taken into account for evaluating combined KIR-HLA associations. KIR2DL2 and 2DS2 were increased significantly in patients than in controls, individually (OR 1.63, and OR 1.42, respectively) and in combination with HLA-C1 ligands (OR 1.99, and OR 1.93, respectively). KIR3DS1 (OR 0.67) and 2DS1 (OR 0.69) were more likely presented in controls in the absence of their relative ligands. The incidence of CxTx subset was increased in lung cancer patients (OR 1.83), and disease risk strikingly increased by more than fivefold among genotype ID19 carriers (a CxTx genotype that carries 2DL2 in the absence of 2DS2, OR 5.92). We found that genotypes with iKIRs > aKIRs (OR 1.67) were more frequently presented in lung cancer patients. Additionally, patients with lung cancer were more likely to carry the combination of CxTx/2DS2 compared to controls (OR 2.04), and iKIRs > aKIRs genotypes in the presence of 2DL2 (OR 2.05) increased the likelihood of lung cancer development. Here we report new susceptibility factors and the contribution of KIR and HLA-I encoding genes to lung cancer risk, highlighting an array of genetic effects and disease setting which regulates NK cell responsiveness. Our results suggest that inherited KIR genes and HLA-I ligands specifying the educational state of NK cells can modify lung cancer risk.

Coexistence of inhibitory and activating killer-cell immunoglobulin-like receptors to the same cognate HLA-C2 and Bw4 ligands confer breast cancer risk

Human leukocyte antigen (HLA) class I-specific killer-cell immunoglobulin-like receptors (KIR) regulate natural killer (NK) cell function in eliminating malignancy. Breast cancer (BC) patients exhibit reduced NK-cytotoxicity in peripheral blood. To test the hypothesis that certain KIR-HLA combinations impairing NK-cytotoxicity predispose to BC risk, we analyzed KIR and HLA polymorphisms in 162 women with BC and 278 controls. KIR-Bx genotypes increased significantly in BC than controls (83.3% vs. 71.9%, OR 1.95), and the increase was more pronounced in advanced-cancer (OR 5.3). No difference was observed with inhibitory KIR (iKIR) and HLA-ligand combinations. The activating KIR (aKIR) and HLA-ligand combinations, 2DS1 + C2 (OR 2.98) and 3DS1 + Bw4 (OR 2.6), were significantly increased in advanced-BC. All patients with advanced-cancer carrying 2DS1 + C2 or 3DS1 + Bw4 also have their iKIR counterparts 2DL1 and 3DL1, respectively. Contrarily, the 2DL1 + C2 and 3DL1 + Bw4 pairs without their aKIR counterparts are significantly higher in controls. These data suggest that NK cells expressing iKIR to the cognate HLA-ligands in the absence of putative aKIR counterpart are instrumental in antitumor response. These data provide a new framework for improving the utility of genetic risk scores for individualized surveillance.

Diversity of KIRs in invasive breast cancer patients and healthy controls along with the clinical significance in ER/PR/HER2+ patients

Killer cell immunoglobulin-like receptors (KIR) consists of activating and inhibitory genes are essential for natural killer cell education. To determine the association of KIRs with susceptibility to invasive Breast cancer (BC), genotyping of 16 KIRs was performed by sequence-specific primers-polymerase chain reaction in 226 confirmed cases of BC with defined estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER2) status and 226 healthy controls (CNs). We observed a lower frequency of 2DL1 and 2DS4del along with increased frequency of 2DS4fl in cases compared to CNs. Further analysis revealed a higher frequency of KIR2DL2, 2DS1, 2DS2,3DS1 in ER+ cases, 2DL2, 2DL5 in PR+ and 2DL1 in HER2+ cases compared to CNs. The detrimental role of KIR2DS4fl was observed in ER+ and PR+ cases whereas 2DS4del confers protection against ER+, PR+, and HER2+ cases. We noted the predisposing role of Bx genotype, KIR2DS1, 2DS2, 2DS5, 2DL2, 2DL5 for lymphatic invasion in ER+ cases along with a higher rate of lymph node metastasis (LNM) in carriers of Bx genotype and KIR2DS1 in ER+ cases. We suggest a link between B haplotype associated genes with the increased risk of lymphatic invasion and LNM, particularly in ER+ cases of BC.