INTERLEUKIN-6 AND NKG2D AS PROGNOSTIC FACTORS IN IRAQI FEMALES WITH PITUITARY GAND ADENOMA: A LONGITUDINAL STUDY.

OBJECTIVE: The aim: To assess the role of circulating IL-6 & NKG2D in the prognosis of pituitary adenoma. PATIENTS AND METHODS: Materials and methods: Thirty female with new diagnosis of prolactinoma (pituitary gland adenoma) were enrolled in the study. ELISA test was used to evaluate the level of IL6 and NKG2D. ELISA tests were conducted before the initiation of treatment and six months later. RESULTS: Results: There are significant differences in mean levels of IL-6 and NKG2D, and the anatomical type (tumor size) (-418.7 & 418.9, p<0.001) of anatomical tumor (-373.72 & -373.920, p=0.001). There is a significant difference between the two immunological markers (IL-6 & NKG2D) (-0.305; p<0.001). The IL-6 markers significantly decreased in means on follow up (-197.8; p-value≤0.0001) while the reverse occur in NKG2D, which increased in levels post-treatment compared with baseline measurement. The high expression of IL-6 positively correlated with the risk of macroadenoma (>10 microns) and poor resonse to treatment and vice versa (p<0.024). High expression of NKG2D significantly (p<0.005) correlated with good prognosis and increased chance for tumor response to medicine and shrinkage in size compared with low concentration. CONCLUSION: Conclusions: The higher the level of IL-6, the larger the size of adenoma (macroadenoma) and the poorer the response to treatment. The higher the level of NKG2D indidcate a better prognosis, therefore, IL-6 and NKG2D correlate negatively in prolactinoma patients.

Changes in NK Cell Subsets and Receptor Expressions in HIV-1 Infected Chronic Patients and HIV Controllers.

Natural killer (NK) cells are major effectors of the innate immune response and purported to play an influential role in the spontaneous control of HIV infection. In the present study, we compared the phenotypes of NK cells in the peripheral blood of three groups of subjects with chronic HIV-1 infection, HIV controllers, and healthy donors. The results showed that CD56+/CD16- NK cell subsets decreased in chronic patients and remained unchanged in controllers. Notably, we found that people living with chronic HIV-1 infection had suppressed NKp80, NKp46, and NKG2D expressions on NK cells compared to healthy donors, while HIV controllers remained unchanged. In contrast, NKG2D expression was substantially higher in controllers than in chronic patients (M=97.67, p<0.001). There were no significant differences in inhibitory receptors KIR3DL1 and KIR2DL1 expressions. In addition, plasma cytokine IFN-γ, TNF-α and IL-12showed higher levels in HIV controllers compared to chronic patients. Overall, our study revealed that, as compared to chronic patients, HIV controllers show an increased activating receptors expression and higher number ofCD56+/CD16-NK cell subset, with increased expression levels of plasma cytokines, suggesting that higher immune activation in controllers may have a key role in killing and suppressing HIV.

Vogt-Koyanagi-Harada patients show higher frequencies of circulating NKG2Dpos NK and NK T cells.

Vogt-Koyanagi-Harada (VKH) is an autoimmune disease characterized by inflammation in tissues that contain melanocytes. We aimed to increase the knowledge regarding immunological pathways deregulated in VKH disease. We compared the percentages of circulating natural killer (NK), NK T and T cells expressing the activatory markers: CD16, CD69, NK group 2D (NKG2D), natural cytotoxicity triggering receptor 3 (Nkp30), natural cytotoxicity triggering receptor 1 (Nkp46) and the inhibitory marker: NK group 2 member A (NKG2A) in 10 active VKH patients, 20 control subjects (CTR) and seven patients with Behçet disease (BD) by flow cytometry. Cytotoxic potential of NK cells was determined through the degranulation marker CD107a expression after contact with K562 cells by flow cytometry. Moreover, plasmatic levels of 27 cytokines were determined with a multiplex bead-based assay. VKH patients showed higher percentages of NKG2Dpos NK and NK T cells versus CTR. The cytotoxic potential of NK cells induced by K562 cells was comparable between VKH patients and CTR. Finally, higher concentrations of interleukin (IL)-4, IL-5, IL-7, IL-17 and platelet-derived growth factor-subunits B (PDGF-bb) were detected in plasma of VKH patients versus CTR. The immune profile of VKH patients was similar to that of BD patients.

Characterization of the immune cell landscape of patients with NAFLD.

Multiple factors are involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), but the exact immunological mechanisms that cause inflammation and fibrosis of the liver remain enigmatic. In this current study, cellular samples of a cohort of NAFLD patients (peripheral blood mononuclear cells (PBMC): n = 27, liver samples: n = 15) and healthy individuals (PBMC: n = 26, liver samples: n = 3) were analyzed using 16-color flow cytometry, and the frequency and phenotype of 23 immune cell subtypes was assessed. PBMC of NAFLD patients showed decreased frequencies of total CD3+, CD8+ T cells, CD56dim NK cells and MAIT cells, but elevated frequencies of CD4+ T cells and Th2 cells compared to healthy controls. Intrahepatic lymphocytes (IHL) of NAFLD patients showed decreased frequencies of total T cells, total CD8+ T cells, Vd2+γδ T cells, and CD56bright NK cells, but elevated frequencies of Vδ2-γδ T cells and CD56dim NK cells compared to healthy controls. The activating receptor NKG2D was significantly less frequently expressed among iNKT cells, total NK cells and CD56dim NK cells of PBMC of NAFLD patients compared to healthy controls. More strikingly, hepatic fibrosis as measured by fibroscan elastography negatively correlated with the intrahepatic frequency of total NK cells (r2 = 0,3737, p = 0,02). Hepatic steatosis as measured by controlled attenuation parameter (CAP) value negatively correlated with the frequency of circulating NKG2D+ iNKT cells (r2 = 0,3365, p = 0,0047). Our data provide an overview of the circulating and intrahepatic immune cell composition of NAFLD patients, and point towards a potential role of NK cells and iNKT cells for the regulation of hepatic fibrosis and steatosis in NAFLD.

Association between the SNPs in trace element-related metabolic genes and the risk of gastric cancer: a case-control study in Xianyou of China.

This study aims to analyse the potential relationship between single-nucleotide polymorphism (SNPs) in trace element related metabolic genes GSTM3, GSTP1, GPX1 and NKG2D and the risk of gastric cancer. A case-control study was conducted in the hospital of Xianyou, Fujian, China. In this study, a total of 299 patients with histopathological diagnosis in gastric cancer and 295 healthy control subjects were involved. Association between the SNPs in trace element-related metabolic genes and gastric cancer risk was analysed using the unconditional logistic regression model. No relationship was found between the SNPs of GSTM3 and GPX1 genes and gastric cancer risk. However, the risk of gastric cancer is related to the SNPs of NKG2D gene (rs1049174). Patients who carry the rs1049174 GG genotype have a higher incidence of the gastric cancer and a multivariate odds ratio (OR) of 1.85 (95% confidence intervals (CI): 1.02-3.38). Through haplotype analysis, two haplotypes (i.e. A_rs1746123-T_rs10431294-G_rs1049174 and T_rs1746123-T_rs10431294-C_rs1049174), OR of 0.29 (95% CI: 0.15-0.56) and 0.33, (95% CI: 0.22-0.50), respectively, were found to have lower incidence of gastric cancer. Meanwhile, another two haplotypes (T_rs1746123-C_rs10431294-C_rs1049174 and T_rs1746123-T_rs10431294-G_rs1049174), OR of 1.81 (95% CI: 1.40-2.34) and 3.09 (95% CI: 2.30-4.16), respectively, were found to have a higher incidence of gastric cancer. Further, no influence of the haplotype on the risk of cardia gastric cancer was found. However, the haplotype T_rs1746123-T_rs10431294-C_rs1049174 had lower incidence of noncardia gastric cancer by 46%. Our data showed that polymorphisms of trace element-related metabolic genes are important in gastric cancer pathology.

Immunomodulatory and Metabolic Changes after Gnetin-C Supplementation in Humans.

Gnetin-C is a naturally occurring stilbene derived from the seeds of Gnetum gnemon L., an edible plant native to Southeast Asia that is called melinjo. Although the biological properties and safety of G. gnemon extract, which contains nearly 3% Gnetin-C, have been confirmed in various human studies, whether or not pure Gnetin-C is safe for humans is unclear at present. We conducted a randomized, double-blind, placebo-controlled trial. Healthy subjects were randomly divided into two groups. The interventional group (n = 6) was given Gnetin-C, and the control group (n = 6) was provided a placebo, for 14 days. Lipid profiles, biomarkers of oxidative stress and circulating blood cells were assessed before and after the intervention. All subjects completed the study, with no side effects reported across the study duration. Gnetin-C supplementation demonstrated a statistically significant increase in the absolute number of circulating natural killer (NK) cells expressing the activating receptors NKG2D and NKp46. NK cells derived from subjects who received Gnetin-C for two weeks showed higher cytotoxicity against K562 target cells than those before receiving Gnetin-C. In addition, Gnetin-C also resulted in a significant decrease in the absolute neutrophil count in the blood compared with the placebo. Furthermore, Gnetin-C significantly reduced the levels of uric acid, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total adiponectin, and high-molecular-weight adiponectin. These data indicate that Gnetin-C has biological effects of enhancing the NK activity on circulating human immune cells. The immunomodulatory effects are consistent with a putative improvement in cancer immunosurveillance via the upregulation of the NKG2D receptor. The study was registered with UMIN-CTR, number 000030364, on 12 December 2017.

Up-regulation of NKG2A inhibitory receptor on circulating NK cells contributes to transfusion-induced immunodepression in patients with ß-thalassemia major.

Accumulating evidence has shown that allogeneic blood transfusions can induce significant immunosuppression in recipients, and thereby increase the risk of postoperative infection and/or tumor relapse. Although it is well known that natural killer (NK) cells are responsible for the immunodepression effects of transfusion, the underlying mechanisms remain obscure. In this study, we investigated the role of NK cells in transfusion-induced immunodepression in ß-thalassemia major. The proportion of circulating NK cells and the expression of NK receptors (NKG2A, CD158a, NKP30, NKP46 and NKG2D) as well as CD107a were detected by multicolor flow cytometry. IFN-γ production by circulating NK cells was detected by intracellular cytokine staining. Our results showed that the proportion and cytotoxicity (CD107a expression) of circulating NK cells in transfusion-dependent ß-thalassemia major patients were remarkably lower than those of ß-thalassemia minor patients or healthy volunteers. Expression of NKG2A inhibitory receptor on circulating NK cells in patients with ß-thalassemia major was remarkably up-regulated, but there were no significant differences in the expression levels of NKP30, NKP46, NKG2D, CD158a and IFN-γ. These results indicate NKG2A inhibitory receptor may play a key role in transfusion-induced immunodepression of NK cells in patients with ß-thalassemia major.

The Effect of G2 Adjuvant on Gene Expression and Delivery of NKG2D Receptor on NK Cells in Peripheral Blood.

INTRODUCTION: Natural killer (NK) cells are a subset of lymphocytes in humans that release cytokines such as tumor necrosis factor alpha and interferon gamma-γ during infection. NKG2D is one of the most important stimulating NK receptors binding MIC-A, MIC-B, and ULBPs, which leads to activation of NK cells against tumor cells. In this study, the authors evaluated the effect of G2 adjuvant on gene expression and delivery of NKG2D receptor on NK cells in peripheral blood. MATERIALS AND METHODS: Peripheral blood mononuclear cells were isolated from venous blood obtained from healthy volunteers after adding G2 adjuvant within 12, 24, and 48 hours of incubation. Then, total RNA was extracted from the cells, cDNA synthesis was performed, and gene expression was evaluated by real-time PCR. In addition, NK cells were stained with the appropriate monoclonal antibodies, and the receptors expressed on cell surface were quantified. RESULTS: G2 adjuvant leads to upregulation of gene expression and increases the expression of NKG2D receptor on the surface of NK cells after incubation. CONCLUSION: The findings of this study demonstrated that G2 adjuvant can increase NK cell cytotoxicity. It may play an important role in killing tumor cells, preventing tumor growth and metastasis.

An approach to the immunophenotypic features of circulating CD4⁺NKG2D⁺ T cells in invasive cervical carcinoma.

BACKGROUND: NKG2D, an activating immunoreceptor, is primarily restricted to NK cells and CD8(+) T cells. The existence of an atypical cytotoxic CD4(+)NKG2D(+) T cell population has also been found in patients with autoimmune dysfunctions. Nonetheless, contradictory evidence has categorized this population with a regulatory rather than cytotoxic role in other situations. These confounding data have led to the proposal that two distinct CD4(+)NKG2D(+) T cell subsets might exist. The immune response elicited in cervical cancer has been characterized by apparent contradictions concerning the role that T cells, in particular T-helper cells, might be playing in the control of the tumor growth. Interestingly, we recently reported a substantial increase in the frequency of CD4(+)NKG2D(+) T cells in patients with cervical intraepithelial neoplasia grade-1. However, whether this particular population is also found in patients with more advanced cervical lesions or whether they express a distinctive phenotype remains still to be clarified. In this urgent study, we focused our attention on the immunophenotypic characterization of CD4(+)NKG2D(+) T cells in patients with well-established cervical carcinoma and revealed the existence of at least two separate CD4(+)NKG2D(+) T cell subsets defined by the co-expression or absence of CD28. RESULTS: Patients with diagnosis of invasive cervical carcinoma were enrolled in the study. A group of healthy individuals was also included. Multicolor flow cytometry was used for exploration of TCR alpha/beta, CD28, CD158b, CD45RO, HLA-DR, CD161, and CD107a. A Luminex-based cytokine kit was used to quantify the levels of pro- and anti-inflammatory cytokines. We found an increased percentage of CD4(+)NKG2D(+) T cells in patients with cervical cancer when compared with controls. Accordingly with an increase of CD4(+)NKG2D(+) T cells, we found decreased CD28 expression. The activating or degranulation markers HLA-DR, CD161, and CD107a were heterogeneously expressed. The levels of IL-1beta, IL-2, TNF-alpha, and IL-10 were negatively correlated with the percentages of CD4(+)NKG2D(+) T cells in patients with cervical carcinoma. CONCLUSIONS: Taken together, our results reveal the existence of two separate CD4(+)NKG2D(+) T cell subsets defined by the co-expression or absence of CD28, the latter more likely to be present in patients with cervical cancer.

The role of soluble HLA-G and HLA-G receptors in patients with hematological malignancies after allogeneic stem cell transplantation.

HLA-G is a non-classical MHC class I molecule whose suppressive activity on immune effector cells is exerted due to interactions with receptors ILT2, ILT4 and KIR2DL4. These receptors are expressed mainly on NK cells and monocytes, and their intensity of expression changes depending on HLA-G level. HLA-G plays an important role in the development of tolerance following organ transplantations and bone marrow stem cell transplantations. HLA-G also participates in the modulation of the immune response during cancerogenesis. The aim of this study was to assess HLA-G level in blood serum, the percentage of NK cells and monocytes with expression of receptors for HLA-G (ILT2, ILT4, KIR2DL4 and NKG2D) in patients who received allogeneic stem cell transplantations, and their influence on the occurrence of graft-versus-host reaction. The study included 32 patients with bone marrow diseases (acute leukemias, myelodysplastic syndrome, chronic myeloid leukemia, paroxysmal nocturnal hemoglobinuria) who received allogeneic stem cell transplantations. We assessed the expression of receptors ILT2, ILT4, KIR2DL4 and NKG2D on monocytes and NK cells, as well as the level of HLA-G in blood serum in patients before conditioning, in the transplant hematopoietic reconstitution period following allogeneic bone marrow stem cell transplantation. The percentage of NK cells with expression of KIR2DL4, ILT2 and ILT4 receptors was higher in patients with 0-I grade GVHD than in patients with II-IV grade GVHD. The percentage of monocytes with expression of ILT4 and ILT2 receptors was higher in patients with 0-I grade GVHD than in patients with II-IV grade GVHD. The level of HLA-G in patients' blood serum was higher after the stem cell transplantation compared with the period before transplantation. HLA-G level and HLA-G receptors are related to intensity of GVHD and may play the role of a prognostic factor for the development of GVHD and the clinical course of this reaction.

Umbilical cord blood plasma contains soluble NKG2D ligands that mediate loss of natural killer cell function and cytotoxicity.

NK cells play a key role in innate elimination of virally infected or neoplastic cells but they can be circumvented by immunoevasive mechanisms enabling viral spread or tumor progression. Engagement of the NKG2D activating receptor with soluble forms of its ligand is one such mechanism of inducing NK cell hyporesponsiveness. Interestingly, this immunoevasive strategy among others is described at the maternal-fetal interface where tolerance of the semi-allogeneic fetus is required to allow successful human pregnancy. Understanding of maternal-fetal tolerance is increasing but mechanisms preventing alloreactivity of fetal immune cells against the maternal host are less well understood. The study of umbilical cord blood has enabled insight of the fetal immune system, which appears immature and inert. We have found that soluble NKG2D ligands (sNKG2DLs) are present in cord blood plasma (CBP) and associate with adult NK cell hyporesponsiveness demonstrated by reduced CD107a expression and secretion of IFN-γ upon stimulation. The capacity of NK cells to kill K562 cells or proliferate was also reduced by incubation with CBP; however, physical removal of sNKG2DL from CBP restored K562 lytic function and NKG2D expression. Therefore, our results strongly suggest sNKG2DLs are expressed in CBP as a mechanism of fetal-maternal tolerance in human pregnancy.

Exercise-induced Natural Killer Cell Activation is Driven by Epigenetic Modifications.

Exercise has been proven to reduce the risk and progression of various diseases, such as cancer, diabetes and neurodegenerative disorders. Increasing evidence suggests that exercise affects the cytokine profile and changes distribution and function of tumor-competitive immune cells. Initial studies have shown that different exercise interventions are associated with epigenetic modifications in different tissues and cell types, such as muscle, fat, brain and blood. The present investigation examines the effect of an intense endurance run (half marathon) on global epigenetic modifications in natural killer (NK) cells in 14 cancer patients compared to 14 healthy controls. We were able to show that histone acetylation and NKG2D expression, a functional NK cell marker, were elevated for at least 24 h after the run. Thus, this is the first study to present a potential mechanism of how exercise may impact NK cell activity on the subcellular level. Further studies should focus on epigenetic mechanisms and dose-dependent effects of exercise.

Expression of NK cell and monocyte receptors in critically ill patients--potential biomarkers of sepsis.

UNLABELLED: Sepsis is characterized by activation of both the innate and adaptive immune systems as a response to infection. During sepsis, the expression of surface receptors expressed on immune competent cells, such as NKG2D and NKp30 on NK cells and TLR4 and CD14 on monocytes, is partly regulated by pro- and anti-inflammatory mediators. In this observational study, we aimed to explore whether the expression of these receptors could be used as diagnostic and/or prognostic biomarkers in sepsis. Patients with severe sepsis or septic shock (n = 21) were compared with critically ill non-septic patients (n = 15). Healthy volunteers (n = 15) served as controls. To elucidate variations over time, all patients were followed for 4 days. Cell surface expression of NKG2D, NKp30, TLR4 and CD14 and serum levels of IL-1ß, IL-6, IFN-γ, TNF-α, IL-4 and IL-10 was estimated by flow cytometry. We found that NK cell expression of NKG2D and monocyte expression of CD14 were lower in the septic patients compared with the non-septic patients, both at ICU admission and during the observation period (P < 0.01 for all comparisons). Both at ICU admission, and during the observation period, levels of IL-6 and IL-10 were higher in the septic patients compared with the non-septic patients (P < 0.001 for all comparisons). CONCLUSION: As both NKG2D and CD14 levels appear to distinguish between septic and non-septic patients, both NKG2D and CD14 may be considered potential diagnostic biomarkers of severe sepsis and septic shock.

Soluble ligands for the NKG2D receptor are released during HIV-1 infection and impair NKG2D expression and cytotoxicity of NK cells.

In humans, the interaction of the natural killer group 2 member D (NKG2D)-activating receptor on natural killer (NK) and CD8(+) T cells with its major histocompatibility complex class I-related chain (MIC) and UL16 binding protein (ULBP) ligands (NKG2DLs) promotes recognition and elimination of stressed cells, such as tumor or infected cells. Here, we investigated the capacity of HIV-1 to modulate NKG2DL expression and escape NGK2D-mediated immunosurveillance. In CD4(+) T lymphocytes, both cell surface expression and release of MICA, MICB, and ULBP2 were up-regulated >2-fold by HIV-1 infection. In HIV-infected CD4(+) T lymphocytes or Jurkat T-cell lines, increased shedding of soluble NKG2DLs (sNKG2DLs) was impaired by a matrix metalloproteinase inhibitor (MMPI). Moreover, naive HIV(+) patients displayed increased plasma sMICA and sULBP2 levels and reduced NKG2D expression on NK and CD8(+) T cells compared to patients receiving highly active antiretroviral therapy (HAART) or healthy donors. In individual patients, HAART uptake resulted in the drop of sNKG2DL and recovery of NKG2D expression. Finally, sNKG2DLs in patients' plasma down-regulated NKG2D on NK and CD8(+) T cells and impaired NKG2D-mediated cytotoxicity of NK cells. Thus, NKG2D detuning by sNKG2DLs may promote HIV-1 immune evasion and compromise host resistance to opportunistic infections, but HAART and MMPI have the potential to avoid such immune dysfunction.

High frequency of activated natural killer and natural killer T-cells in patients with new onset of type 2 diabetes mellitus.

Chronic low-grade inflammation is crucial for the development of insulin resistance and type 2 diabetes mellitus (T2DM), and immunocompetent cells, such as T-cells, B-cells, mast cells and macrophages, regulate the pathogenesis of T2DM. However, little is known about the role of natural killer (NK) and natural killer T (NKT) cells in the pathogenic process of T2DM. A total of 16 patients with new onset T2DM and nine healthy subjects were recruited, and the frequency of peripheral blood activated and inhibitory NK and NKT cells in individual subjects was determined by flow cytometry. The frequency of spontaneous and inducible interferon gamma (IFN-γ) and CD107a(+) NK cells was further examined, and the potential association of the frequency of NK cells with clinical measures was analyzed. While there was no significant difference in the frequency of peripheral blood NK and NKT cells between patients and controls, the frequency of NKG2D(+) NK and NKT cells in patients was significantly higher than those in the controls (P = 0.011). In contrast, the frequency of NKG2A(+) and KIR2DL3(+) inhibitory NK and NKT cells in patients was significantly lower than those in the controls (P = 0.002, P < 0.0001, respectively). Furthermore, the frequencies of NKG2D(+) NK cells were correlated significantly with the values of body mass index in patients. Moreover, the frequencies of spontaneous and inducible CD107a(+), but not IFN-γ-secreting, NK cells in patients were significantly higher than those in the controls (P < 0.004, P < 0.0001). Our data indicated that a higher frequency of activated NK cells may participate in the obesity-related chronic inflammation involved in the pathogenesis of T2DM.

[Expression and clinical significance of CD8+natural killer T cell stimulatory receptor NKG2D in peripheral blood of lung cancer patients].

BACKGROUND AND OBJECTIVE: NKG2D-expressing CD8+NKT cells and soluble major histocompatibility complex class I-related chain A (sMICA) is one of recently emerged general interests in tumor research area. The aim of this study is to investigate the levels of NKG2D-expressing CD8+NKT cells in peripheral blood of lung cancer patients, which are remarkably related to clinical significance, and to analyze the correlation between NKG2D-expressing CD8+NKT cells and sMICA levels, and to explore the role of NKG2D and sMICA in immune surveillance. METHODS: Flow cytometry was used to determine the percentage of NKG2D-expressing CD8+NKT cells, and ELISA was used to measure the levels of sMICA in peripheral blood of 82 untreated lung cancer patients and 45 healthy controls. The association of NKG2D levels with clinical features was analyzed. RESULTS: The expression of NKG2D on CD8+NKT cells in lung cancer group was significantly lower than that in healthy group, with statistically significant difference (P < 0.001). And with the increase of TNM stage, NKG2D expression rate reduced gradually. NKG2D expression in stage IV disease was significantly lower than which stage I-II and III disease (P < 0.001). The expression of NKG2D on CD8+NKT cells was remarkably lower in that in smokers than that in non-smokers, with statistically significant difference (P < 0.05). NKG2D exhibited negative correlation with sMICA (r=-0.598, P < 0.001). CONCLUSIONS: Lung cancer has low expression of NKG2D in CD8+NKT cells which correlate with pathological stage. Detection of NKG2D and sMICA might be helpful to understand immune functions and provide evaluation of combined treatment for clinical cancer.

Novel aspects of in vitro IL-2 or IFN-α enhanced NK cytotoxicity of healthy individuals based on NKG2D and CD161 NK cell receptor induction.

As IL-2 and IFN-α modulate NK cell activity it was of interest to investigate the expression of newly defined NK cell receptors and augmented NK cell activity in healthy individuals after cytokine in vitro treatment. Peripheral blood lymphocytes (PBL) obtained from 31 healthy volunteers treated for 18 h with 200 IU/ml IL-2 and 250 IU/ml IFN-α were evaluated for NK cell cytotoxicity. Expression of NKG2D, CD161, CD158a, CD158b receptors was analyzed on CD3⁻CD16+ NK cells, cytotoxic CD16(bright) and regulatory CD16(dim) subsets by FACS flow. The found induced significant in vitro enhancement of NK cell activity by both cytokines is supported by specific cytokine induction in PBL of pSTAT1 and pSTAT5, determined by Western blotting, as well as induction of IRF-1 transcription. Both cytokines induce significant up-regulation of NKG2D expression while only IFN-α induced significant up-regulation of CD161, with no alteration in KIR expression by either cytokine on CD3⁻CD16+ NK cells. Investigated cytokines did not induce change in NK cell bright and dim subset distribution. Moreover, we find that, not only cytokine receptor induction on the CD3⁻CD16+ NK cells, but also simultaneous increase in their percentage and/or density on CD16(bright) and CD16(dim) subsets, represent good indicators of receptor cytokine-susceptibility. As the role of NK cells has been shown in the loss of tolerance, infection and cancer, the data obtained in this study may be of help in NK cell profiling, by giving referent values of cytokine-induced novel NK cell receptor expression either in evaluation of these diseases or in immunomonitoring during cytokine immunotherapy.

Altered natural killer (NK) cell frequency and phenotype in latent autoimmune diabetes in adults (LADA) prior to insulin deficiency.

Approximately 10% of the patients diagnosed with type 2 diabetes (T2D) have detectable serum levels of glutamic acid decarboxylase 65 autoantibodies (GADA). These patients usually progress to insulin dependency within a few years, and are classified as being latent autoimmune diabetes in adults (LADA). A decrease in the frequency of peripheral blood natural killer (NK) cells has been reported recently in recent-onset T1D and in high-risk individuals prior to the clinical onset. As NK cells in LADA patients have been investigated scarcely, the aim of this study was to use multicolour flow cytometry to define possible deficiencies or abnormalities in the frequency or activation state of NK cells in LADA patients prior to insulin dependency. All patients were GADA-positive and metabolically compensated, but none were insulin-dependent at the time blood samples were taken. LADA patients exhibited a significant decrease in NK cell frequency in peripheral blood compared to healthy individuals (P=0.0018), as reported previously for recent-onset T1D patients. Interestingly, NKG2D expression was increased significantly (P<0.0001), whereas killer cell immunoglobulin-like receptor (KIR)3DL1 expression was decreased (P<0.0001) within the NK cell population. These observations highlight a defect in both frequency and activation status of NK cells in LADA patients and suggest that this immunological alteration may contribute to the development of autoimmune diabetes by affecting peripheral tolerance. Indeed, recent evidence has demonstrated a regulatory function for NK cells in autoimmunity. Moreover, the decrease in NK cell number concords with observations obtained in recent-onset T1D, implying that similar immunological dysfunctions may contribute to the progression of both LADA and T1D.

Association of an NKG2D gene variant with systemic lupus erythematosus in two populations.

NKG2D, involved in T-cell activation and viral defense, shows a single-nucleotide polymorphism (SNP) in the transmembrane region, characterized by a substitution of alanine with threonine. We examined the association of systemic lupus erythematosus (SLE) with one of the NKG2D gene variants. We also studied the functional impact of that allele in SLE. Restriction fragment length polymorphism/polymerase chain reaction specific for the SNP rs2255336 G--> A was performed with 247 German SLE patients and 447 controls and with 284 Spanish SLE patients and 180 controls. NKG2D expression on peripheral blood lymphocytes of SLE patients was analyzed via fluorescence activated cell sorter. In addition, proliferation assays were performed. We found that the NKG2D alanine/alanine (G/G) gene variant was significantly associated with SLE in the German cohort (70.4% vs 60.8% controls; p = 0.0027) and almost significantly in the Spanish cohort (66.2% vs 62.2% controls; p = 0.054). In a pooled analysis, the prevalence of G/G was 68.2% in SLE versus 61.2% in the controls (p = 0.0024). There were no significant differences in the expression levels of NKG2D on peripheral blood lymphocytes of the different genotypes. A comparison of the coreceptor activity of the genotypes in response to CD3 and NKG2D antibodies revealed a trend toward higher proliferation in the A/A genotype. In conclusion, based on our study results, SLE is associated with the SNP rs2255336 of NKG2D.