Genetic interactions of KIR and G1M immunoglobulin allotypes differ in obese from non-obese individuals with type 2 diabetes

Obesity-Associated Alterations of Natural Killer Cells and Immunosurveillance of Cancer

Obesity is accompanied by a systemic chronic low-grade inflammation as well as dysfunctions of several innate and adaptive immune cells. Recent findings emphasize an impaired functionality and phenotype of natural killer (NK) cells under obese conditions. This review provides a detailed overview on research related to overweight and obesity with a particular focus on NK cells. We discuss obesity-associated alterations in subsets, distribution, phenotype, cytotoxicity, cytokine secretion, and signaling cascades of NK cells investigated in vitro as well as in animal and human studies. In addition, we provide recent insights into the effects of physical activity and obesity-associated nutritional factors as well as the reduction of body weight and fat mass on NK cell functions of obese individuals. Finally, we highlight the impact of impaired NK cell physiology on obesity-associated diseases, focusing on the elevated susceptibility for viral infections and increased risk for cancer development and impaired treatment response.

Poor ovarian response is associated with serum vitamin D levels and pro-inflammatory immune responses in women undergoing in-vitro fertilization

Poor ovarian response (POR¹) limits the success of infertility treatment modality. In this study, we aim to investigate if POR is associated with serum 25(OH) vitamin D (VD²) levels and pro-inflammatory immune responses in infertile women with a history of in-vitro fertilization and embryo transfer failures. A retrospective cross-sectional study included 157 women with IVF failures. Study patients were divided into four groups based on serum 25(OH)VD level and ovarian responses during the most recent IVF cycle; low VD (LVD³) with POR, LVD with normal ovarian response (NOR⁴), normal VD (NVD⁵) with POR, and NVD with NOR. Serum 25(OH)VD level, cellular- and auto-immunity, and metabolic parameters, including homocysteine and plasminogen activator inhibitor-1 were investigated. Peripheral blood CD56⁺ NK cell levels (%) and NK cytotoxicity were significantly higher in POR-LVD when compared to the other groups (P < 0.05, respectively). CD19 + B and CD19+/5+ B-1 cell levels were significantly higher in women with POR-LVD as compared with those of NOR-LVD and POR-NVD (P < 0.05, respectively). TNF-α/IL-10 producing Th1/Th2 cell ratio of POR-LVD was significantly higher than those of POR-NVD and NOR-NVD (P < 0.05 respectively). Peripheral blood homocysteine level of POR-LVD was significantly higher than those of NOR-LVD and POR-NVD (P < 0.05 respectively). We conclude that assessment of cellular and autoimmune abnormalities and metabolic factors, such as homocysteine should be considered in women with POR and LVD. VD and folic acid supplementation may be explored further as a possible therapeutic option for POR with immune and metabolic etiologies.

Unusual Suspects in the Development of Obesity-Induced Inflammation and Insulin Resistance: NK cells, iNKT cells, and ILCs

The notion that obesity-induced inflammation mediates the development of insulin resistance in animal models and humans has been gaining strong support. It has also been shown that immune cells in local tissues, in particular in visceral adipose tissue, play a major role in the regulation of obesity-induced inflammation. Specifically, obesity increases the numbers and activation of proinflammatory immune cells, including M1 macrophages, neutrophils, Th1 CD4 T cells, and CD8 T cells, while simultaneously suppressing anti-inflammatory cells such as M2 macrophages, CD4 regulatory T cells, regulatory B cells, and eosinophils. Recently, however, new cell types have been shown to participate in the development of obesity-induced inflammation and insulin resistance. Some of these cell types also appear to regulate obesity. These cells are natural killer (NK) cells and innate lymphoid cells (ILCs), which are closely related, and invariant natural killer T (iNKT) cells. It should be noted that, although iNKT cells resemble NK cells in name, they are actually a completely different cell type in terms of their development and functions in immunity and metabolism. In this review, we will focus on the roles that these relatively new players in the metabolism field play in obesity-induced insulin resistance and the regulation of obesity.

Association between killer cell immunoglobulin-like receptor (KIR) polymorphisms and systemic lupus erythematosus (SLE) in populations: A PRISMA-compliant meta-analysis

BACKGROUND

Recently, a growing number of studies show that the killer cell immunoglobulin-like receptor (KIR) gene polymorphisms may play a role in the systemic lupus erythematosus (SLE) susceptibility. Nonetheless, the results were inconsistent. Thus, a meta-analysis was carried out by integrating multiple research to clarify the association between KIR polymorphisms and SLE susceptibility.

METHODS

The Web of Science, Embase (Ovid), PubMed, Elsevier Science Direct, the Chinese Biomedical Database and CNKI, Wanfang databases (last search was updated on May 15, 2016) were systematically searched to select studies on addressing the association between the KIR polymorphisms and susceptibility to SLE in populations. The odds ratio (OR) with 95% confidence interval (95% CI) was calculated.

RESULTS

A total of 10 published case-control studies involving 1450 SLE patients and 1758 controls were available for this meta-analysis. Results suggested that KIR2DL1 might be a risk factor for SLE (OR 2DL1 =1.047, 95% CI=1.011-1.083) in all subjects. The KIR2DL3, KIR2DL5 were identified as protective factors for SLE in Asian populations (OR2DL3= 0.215, 95% CI = 0.077-0.598; OR2DL5 = 0.588, 95% CI = 0.393-0.881), but not in Caucasians.

CONCLUSIONS

The meta-analysis results suggested that 2DL1 might be a potential risk factor and 2DL3, 2DL5 might be protective factors for SLE in Asians but not in Caucasians.

Host-virus interactions in hepatitis B and hepatitis C infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are among the most endemic pathogens worldwide, with more than 500 million people globally currently infected with these viruses. These pathogens can cause acute and chronic hepatitis that progress to liver cirrhosis or hepatocellular carcinoma. Both viruses utilize multifaceted strategies to evade the host surveillance system and fall below the immunological radar. HBV has developed specific strategies to evade recognition by the innate immune system and is acknowledged to be a stealth virus. However, extensive research has revealed that HBV is recognized by dendritic cells (DCs) and natural killer (NK) cells. Indoleamine-2, 3-dioxygenase is an enforcer of sequential immune reactions in acute hepatitis B, and this molecule has been shown to be induced by the interaction of HBV-infected hepatocytes, DCs, and NK cells. The interleukin-28B genotype has been reported to influence HCV eradication either therapeutically or spontaneously, but the biological function of its gene product, a type-III interferon (IFN-λ3), remains to be elucidated. Human BDCA3(+)DCs have also been shown to be a potent producer of IFN-λ3 in HCV infection, suggesting the possibility that BDCA3(+)DCs could play a key role in developing therapeutic HCV vaccine. Here we review the current state of research on immune responses against HBV and HCV infection, with a specific focus on innate immunity. A comprehensive study based on clinical samples is urgently needed to improve our understanding of the immune mechanisms associated with viral control and thus to develop novel immune modulatory therapies to cure chronic HBV and HCV infection.

Host-virus interactions in hepatitis B and hepatitis C infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are among the most endemic pathogens worldwide, with more than 500 million people globally currently infected with these viruses. These pathogens can cause acute and chronic hepatitis that progress to liver cirrhosis or hepatocellular carcinoma. Both viruses utilize multifaceted strategies to evade the host surveillance system and fall below the immunological radar. HBV has developed specific strategies to evade recognition by the innate immune system and is acknowledged to be a stealth virus. However, extensive research has revealed that HBV is recognized by dendritic cells (DCs) and natural killer (NK) cells. Indoleamine-2, 3-dioxygenase is an enforcer of sequential immune reactions in acute hepatitis B, and this molecule has been shown to be induced by the interaction of HBV-infected hepatocytes, DCs, and NK cells. The interleukin-28B genotype has been reported to influence HCV eradication either therapeutically or spontaneously, but the biological function of its gene product, a type-III interferon (IFN-λ3), remains to be elucidated. Human BDCA3(+)DCs have also been shown to be a potent producer of IFN-λ3 in HCV infection, suggesting the possibility that BDCA3(+)DCs could play a key role in developing therapeutic HCV vaccine. Here we review the current state of research on immune responses against HBV and HCV infection, with a specific focus on innate immunity. A comprehensive study based on clinical samples is urgently needed to improve our understanding of the immune mechanisms associated with viral control and thus to develop novel immune modulatory therapies to cure chronic HBV and HCV infection.

Association between KIR polymorphisms and ankylosing spondylitis in populations: a meta-analysis

OBJECTIVES

Published association studies of killer cell immunoglobulin-like receptors (KIRs) and ankylosing spondylitis (AS) in populations are inconsistent. The aim of this study is to determine whether the KIR polymorphisms confer susceptibility to AS in populations by conducting a meta-analysis.

METHODS

A computer search was carried out up to August 2013 for literature pertaining to AS and KIR polymorphisms. Publications addressing the association between the KIR polymorphisms and susceptibility to AS in populations were selected from the Pubmed, Elsevier Science Direct, China National Knowledge Infrastructure (CNKI) and Chinese Biomedical Literature Database (CBM) databases. The odds ratio (OR) with 95% confidence interval (95%CI) was calculated.

RESULTS

A total of 13 case-control studies in 9 articles were included in this meta-analysis. Meta-analysis results identified two positive associations of 2DS4 and 3DS1 with susceptibility to AS in populations. In subgroup analysis, there was a positive association between 2DS4 and susceptibility to AS in Asians, but not in Caucasians. And there were associations between 3DL1, 3DS1 and susceptibility to AS in Caucasians, but not in Asians. Results of subgroup analysis also showed that there were associations between 2DL5, 2DS4, 2DS5, 3DL1, 3DS1 and susceptibility to AS in HLA-B*27-positive patients and HLA-B*27-positive healthy controls.

CONCLUSIONS

This meta-analysis confirms that 2DS4 and 3DS1 might be potential risk factors for AS in populations.

IL28B polymorphism and genetic biomarkers of viral clearance in hepatitis C virus infection

Infection with hepatitis C virus (HCV) is a major global health issue. Only a small proportion of patients clear the virus spontaneously and the majority develop chronic hepatitis C infection. Chronic hepatitis C is one of the most common causes of advanced liver disease in the western world and is now the leading indication for liver transplantation. Unfortunately, the standard treatment, consisting of pegylated-interferon and ribavirin, is suboptimal. Less than 50% of patients infected with HCV genotype 1 are cured, treatment is costly and is associated with significant toxicity. Therefore, there has been a need to identify accurate predictors of treatment outcome to facilitate treatment decision-making. Four independent genome-wide association studies have recently confirmed an association between genetic variation in the region of the IL28B gene and treatment outcome in HCV-1 patients. Patients who carry the good response variant are two- to three-fold more likely to be cured. The difference in the frequency of the good response variant between patients of different ethnic background explains much of the recognized ethnic disparity in treatment response rates. The IL28B variants are also associated with likelihood of spontaneous clearance of HCV infection. This discovery represents a significant advance in our ability to personalize HCV therapy, as well as suggesting novel avenues for research into viral pathogenesis and therapeutic development.

Interaction between immunoglobulin allotypes and NK receptor genes in diabetes post-hepatitis C virus infection

Genetic interactions between natural killer (NK) cells immunoglobulin-like receptor (KIR) genes and immunoglobulin allotypes have been previously reported in type 2 diabetes mellitus (DM) patients. Puerto Rican Americans with a history of intravenous drug use who developed DM following HCV infection (n=32) were compared to individuals infected with HCV without diabetes (n=121) and to DM non-infected individuals (n=95). Subjects were genotyped for KIRs and immunoglobulin allotypes. We found interactions of immunoglobulin allotypes KM3/KM3 with NK inhibitory receptors 2DL3/2DL3, 2DL1 in the absence of 2DS4 associated with susceptibility to DM in HCV infected individuals. These data suggest the possibility that a subset of patients with HCV could have an immune-mediated component contributing to the development of DM.