Associations of killer cell immunoglobulin like receptors with rheumatoid arthritis among North Indian population

Association of killer cell immunoglobulin-like receptor genes with primary Sjögren's syndrome among Chinese population

BACKGROUND

Primary Sjögren's syndrome (pSS) is a chronic and common autoimmune disorder which is caused by inflammatory infiltration of the exocrine glands salivary glands and lacrimal glands are the main sites of involvement. Killer cell immunoglobulin-like receptors (KIRs), are crucial for the development and function of natural killer (NK) cells. Moreover, the activity of NK cells is affected by the interaction of KIRs with HLA class I ligands. The pathogenesis of autoimmune diseases has been linked to some KIR genes. Further research on the relationship between KIR and these autoimmune diseases is of great significance for the diagnosis and treatment of these diseases. This study aimed to detect and analyze the connection between the polymorphism of the KIR and HLA-Cw genes and the pathogenesis of pSS.

METHODS

We took 56 pSS patients as the study group and 32 healthy people as the control group. Blood samples were collected to perform a polymerase chain reaction with sequence specific primers (PCR-SSP). Then a comparative analysis of gene frequencies of 16 KIR genes and HLA-Cw in the two groups was performed.

RESULTS

The genotype frequencies of both KIR2DS3 (P = 0.0027) and KIR3DS1 (P = 0.006) were significantly lower in patients with pSS compared to healthy individuals, indicating a negative correlation of these two activating KIR genes. There were more individuals who had more than three activating KIR genes in the control group than in the patient group (P = 0.004). And the KIR2DL1/HLA-C2 gene combination (P = 0.022) was significantly more in pSS group than in controls.

CONCLUSION

Our results may imply that via influencing the activity, development, capacitation, and functionality of NK cells, NKT cells, and part T cells, the decrease of activated KIR genes and the increase of the frequency of the inhibitory KIR and its specific ligand gene combination（KIR2DL1/HLA-C2) may contribute to the pathogenesis of pSS.

Transcriptomic profiling reveals gene expression in human peripheral blood after exposure to low-dose ionizing radiation

Although the health effects of exposure to low-dose ionizing radiation have been the focus of many studies, the affected biological functions and underlying regulatory mechanisms are not well-understood. In particular, the influence of radiation exposure at doses of less than 200 mGy on the regulation of genes and pathways remains unclear. To investigate the molecular alterations induced by varying doses of low-dose radiation (LDR), transcriptomic analysis was conducted based on ribonucleic acid (RNA) sequencing following exposure to 50 and 150 mGy doses. Human peripheral blood was collected, and the samples were divided into three groups, including two treatments and one control (no radiation). A total of 876 (318 upregulated and 558 downregulated) and 486 (202 upregulated and 284 downregulated) differentially expressed genes (DEGs) were identified after exposure to 50 mGy and 150 mGy, respectively. Most upregulated genes in both the 50 mGy and 150 mGy groups were associated with 'antigen processing and presentation,' which appeared to be the major targets affected by LDR exposure. Several interacting genes, including HLA-DQA1, HLA-DQA2, HLA-DQB2, HLA-DRB1, and HLA-DRB5 were mapped to 'antigen processing and presentation,' 'immune system-related diseases' and the 'cytokine-mediated signaling pathway,' suggesting that these genes might drive the downstream transmission of these signal transduction pathways. Our results suggest that exposure to LDR may elicit changes in key genes and associated pathways, probably helping further explore the biological processes and molecular mechanism responsible for low-dose occupational or environmental exposures in humans.

The Role of Natural Killer Cells in Autoimmune Diseases

Natural killer (NK) cells, the large granular lymphocytes differentiated from the common lymphoid progenitors, were discovered in early 1970's. They are members of innate immunity and were initially defined by their strong cytotoxicity against virus-infected cells and by their important effector functions in anti-tumoral immune responses. Nowadays, NK cells are classified among the recently discovered innate lymphoid cell subsets and have capacity to influence both innate and adaptive immune responses. Therefore, they can be considered as innate immune cells that stands between the innate and adaptive arms of immunity. NK cells don't express T or B cell receptors and are recognized by absence of CD3. There are two major subgroups of NK cells according to their differential expression of CD16 and CD56. While CD16+CD56dim subset is best-known by their cytotoxic functions, CD16-CD56bright NK cell subset produces a bunch of cytokines comparable to CD4+ T helper cell subsets. Another subset of NK cells with production of interleukin (IL)-10 was named as NK regulatory cells, which has suppressive properties and could take part in immune-regulatory responses. Activation of NK cells is determined by a delicate balance of cell-surface receptors that have either activating or inhibitory properties. On the other hand, a variety of cytokines including IL-2, IL-12, IL-15, and IL-18 influence NK cell activity. NK-derived cytokines and their cytotoxic functions through induction of apoptosis take part in regulation of the immune responses and could contribute to the pathogenesis of many immune mediated diseases including ankylosing spondylitis, Behçet's disease, multiple sclerosis, rheumatoid arthritis, psoriasis, systemic lupus erythematosus and type-1 diabetes. Dysregulation of NK cells in autoimmune disorders may occur through multiple mechanisms. Thanks to the rapid developments in biotechnology, progressive research in immunology enables better characterization of cells and their delicate roles in the complex network of immunity. As NK cells stand in between innate and adaptive arms of immunity and "bridge" them, their contribution in inflammation and immune regulation deserves intense investigations. Better understanding of NK-cell biology and their contribution in both exacerbation and regulation of inflammatory disorders is a requisite for possible utilization of these multi-faceted cells in novel therapeutic interventions.

Natural Killer Cells: Potential Biomarkers and Therapeutic Target in Autoimmune Diseases?

Autoimmune diseases recognize a multifactorial pathogenesis, although the exact mechanism responsible for their onset remains to be fully elucidated. Over the past few years, the role of natural killer (NK) cells in shaping immune responses has been highlighted even though their involvement is profoundly linked to the subpopulation involved and to the site where such interaction takes place. The aberrant number and functionality of NK cells have been reported in several different autoimmune disorders. In the present review, we report the most recent findings regarding the involvement of NK cells in both systemic and organ-specific autoimmune diseases, including type 1 diabetes (T1D), primary biliary cholangitis (PBC), systemic sclerosis, systemic lupus erythematosus (SLE), primary Sjögren syndrome, rheumatoid arthritis, and multiple sclerosis. In T1D, innate inflammation induces NK cell activation, disrupting the Treg function. In addition, certain genetic variants identified as risk factors for T1D influenced the activation of NK cells promoting their cytotoxic activity. The role of NK cells has also been demonstrated in the pathogenesis of PBC mediating direct or indirect biliary epithelial cell destruction. NK cell frequency and number were enhanced in both the peripheral blood and the liver of patients and associated with increased NK cell cytotoxic activity and perforin expression levels. NK cells were also involved in the perpetuation of disease through autoreactive CD4 T cell activation in the presence of antigen-presenting cells. In systemic sclerosis (SSc), in addition to phenotypic abnormalities, patients presented a reduction in CD56^hi NK-cells. Moreover, NK cells presented a deficient killing activity. The influence of the activating and inhibitory killer cell immunoglobulin-like receptors (KIRs) has been investigated in SSc and SLE susceptibility. Furthermore, autoantibodies to KIRs have been identified in different systemic autoimmune conditions. Because of its role in modulating the immune-mediated pathology, NK subpopulation could represent a potential marker for disease activity and target for therapeutic intervention.

A comprehensive overview on the genetics of Behçet's disease

Behçet's disease (BD) is a systemic and inflammatory disease, characterized mainly by recurrent oral and genital ulcers, eye involvement, and skin lesions. Although the exact etiopathogenesis of BD remains unrevealed, a bulk of studies have implicated the genetic contributing factors as critical players in disease predisposition. In countries along the Silk Road, human leukocyte antigen (HLA)-B51 has been reported as the strongest genetically associated factor for BD. Genome-wide association studies, local genetic polymorphism studies, and meta-analysis of combined data from Turkish, Iranian, and Japanese populations have also identified new genetic associations with BD. Among these, other HLA alleles such as HLA-B*15, HLA-B*27, HLA-B*57, and HLA-A*26 have been found as independent risk factors for BD, whereas HLA-B*49 and HLA-A*03 are independent protective alleles for BD. Moreover, other genes have also reached the genome-wide significance level of association with BD susceptibility, including IL10, IL23R-IL12RB2, IL12A, CCR1-CCR3, STAT4, TNFAIP3, ERAP1, KLRC4, and FUT2. Also, several rare nonsynonymous variants in TLR4, IL23R, NOD2, and MEFV genes have been reported to be involved in BD pathogenesis. According to genetic determinants in the loci outside the MHC region that are contributed to the host defense, immunity, and inflammation pathways, it is suggested that immune responses to the pathogen as an important environmental factor and mucosal immunity contribute to BD susceptibility.

Assessment of the Relationship between Clinical Variants of Psoriasis and Killer Immunoglobulin-like Receptor (KIR) Genes: A Systematic Review with Meta-analysis

BACKGROUND

Psoriasis (Ps) is an autoimmune dermatosis. Previous studies have shown an association between KIR genes and susceptibility to some clinical variants of Ps. Therefore, we conducted an exhaustive systematic review with meta-analysis to evaluate the relationship between KIR genes and susceptibility to clinical variants of Ps in the overall population and according to ethnicity.

METHODS

According to PRISMA guidelines, we performed a systematic review through PubMed and Web of Science to identify relevant available scientific publications about KIR genes and Ps. The quality of the studies was evaluated using the Newcastle-Ottawa scale. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using random and fixed effect models for the analyzed genes. Heterogeneity was tested using Cochran's Q-Statistic and I², and the risk of bias was tested using the Begg test and Egger linear regression.

RESULTS

A total of 10 case-control studies were included, comprising a variable number of KIR typified genes and psoriasis vulgaris (PsV) as the main clinical variant studied. In the total pooled results, the KIR2DS1 gene (OR = 1.518, p = .010, 95%CI: 1.105 to 2.086) was related to higher susceptibility to PsV, while the KIR2DS4 (OR = 0.563, p = .005, 95%CI: 0.376 to 0.842) and KIR3DL1 (OR = 0.602, p = .040, 95%CI: 0.370 to 0.977) genes were related to protection against PsV.

CONCLUSION

This meta-analysis demonstrates that subjects that carry the KIR2DS1 gene could have a potential risk factor for the development of PsV. Conversely, KIR2DS4 and 3DL1 genes appear to confer protection against PsV.

Significance of KIR like natural killer cell receptors in autoimmune disorders

Killer cell immunoglobulin-like receptors (KIRs), act as the regulators for the cytolytic activity of natural killer and certain T cells by interacting with the HLA class I ligands. KIRs have been shown to contribute to the pathogenesis of several autoimmune diseases. However, their specific roles are still not very clear. Autoimmune diseases are multifactorial in nature, highlighting the influence of both genetic and environmental factors. The innate immune response plays an important role in autoimmunity as it alters the self-glycans that mimic molecular patterns found on different intracellular pathogens. Natural killer (NK) cells have an important position in the innate immune response. NK cell receptors are encoded by the leukocyte receptor complex located on the chromosome 19q13.4 and lectin-like receptors on chromosome 12p13. This review focuses on the role of KIRs and their relationship with different autoimmune diseases.

Diversity and association of HLA/KIR receptors with type 2 diabetes in South India

The present study was undertaken to delineate the association(s) of KIR-HLA combination in South Indian Type 2 diabetes mellitus (T2DM) patients. The T2DM patients (n = 343) and healthy controls (n = 309) were genotyped for KIR/HLA ligands by PCR-SSP method. The increased frequency of activatory KIR (aKIR) 2DS2 (OR = 1.91; p < 2.91 × 10^-4 ) was observed in patients suggesting a susceptible association. The frequencies of iKIR 2DL2 (OR = 0.38; p < 1.55 × 10^-5 ) and aKIRs 2DS1 (OR = 0.60; p < 0.001) and 3DS1 (OR = 0.52; p < 5.83 × 10^-5 ) were decreased in patients suggesting protective associations. The C1/C2 combinatorial analysis has revealed an increased frequency of C1⁺ /C2^- in T2DM patients (OR = 1.62; p < 0.014). The KIR "AB" genotype (OR = 2.41; p < 3.87 × 10^-5 ) was observed to be higher in patients. However, the "BB" genotype (OR = 0.32; p < 4.71 × 10^-7 ) was increased in controls. The KIR motifs, "Tel-B/B" (OR = 1.84; p < 0.007), were observed higher among patients. However, the frequency of "Tel-A/B" motif genotype was decreased in patients (OR = 0.56; p < 3.13 × 10^-4 ). The iKIR/HLA combinations such as 2DL2/3 +C1 and 3DL2+A3/A11 were increased in patients (OR = 3.90; p < 7.5 × 10^-5 ) suggesting susceptible associations. On the contrary, the aKIR+HLA combinations such as 2DS2+C1, 2DS1+C2 and 3DS1+Bw4 were less frequent in patients (OR = 0.32; p < 4.2 × 10^-4 ) suggesting protective associations. Thus, the present study clearly establishes the positive and negative associations of different KIR-HLA receptor combinations with T2DM in South India.

Association study between KIR polymorphisms and rheumatoid arthritis disease: an updated meta-analysis

Background

Currently published studies investigating association between the killer cell immunoglobulin-like receptor (KIR) gene polymorphisms and rheumatoid arthritis (RA) reported inconsistent and contradictory results. Hence, we aim to carry out this comprehensive meta-analysis of all eligible studies meeting the inclusion criteria to achieve precise and comprehensive relationships between genetic variations in KIR gene cluster and risk of RA.

Methods

Databases of Medline/PubMed and Scopus were searched to investigate case-control studies prior to May 2018. The associations between KIR gene polymorphisms and RA susceptibility were analyzed by computing the odds ratio (OR) and 95% confidence interval (95% CI) for each study.

Results

A total of 11 comparative case-control studies involving 1847 RA patients and 2409 healthy individuals were included in this meta-analysis. Four significant associations of 2DL3 (OR = 0.591, 95% CI = 0.351–0.994; P = 0.047), 2DL5 (OR = 0.716, 95% CI = 0.601–0.853; P < 0.001), 2DS5 (OR = 0.623, 95% CI = 0.393–0.988; P = 0.045), and 3DL3 (OR = 0.324, 95% CI = 0.129–0.814; P = 0.016) genes with decreased RA risk were discovered in this meta-analysis. Although, other KIR receptors including 2DL1, 2DL2, 2DL4, 3DL1, 3DL2, 3DS1, 2DS1-2DS4, and two pseudo gens of 2DP1 and 3DP1 displayed no significant association with predisposition to RA.

Conclusions

These findings provide reliable evidence that 2DL3, 2DL5, 3DL3, and 2DS5 might have a potential protective role for RA.

Association study between killer immunoglobulin-like receptor polymorphisms and ankylosing spondylitis disease: An updated meta-analysis

BACKGROUND

Several genetic studies have assessed the association between polymorphisms in killer immunoglobulin-like receptors (KIR) genes and susceptibility of individuals to ankylosing spondylitis (AS), but the findings have been inconclusive and incongruous. Therefore, we conducted this meta-analysis of all case-control studies meeting the inclusion criteria for obtaining an exact conclusion of the effect of KIR polymorphisms on the risk of AS.

METHODS

A systematic literature search was conducted in electronic databases, including Scopus web of science, ScienceDirect, and PubMed to find all eligible studies exploring the association between KIR polymorphisms and the risk of AS, prior to June 2017. Pooled odds ratios (OR) and their corresponding 95% CIs were used to evaluate the strength of the association between KIR polymorphisms and the risk of AS.

RESULTS

A total of 16 case-control studies, encompassed in 12 papers, with 1770 cases and 2907 healthy subjects were included in the meta-analysis. This meta-analysis revealed three significant positive associations of 2DS1, 2DS5, and 3DS1 with susceptibility to AS, while two significant negative associations of 2DL2 and 2DS2 with susceptibility to AS were identified. In the subgroup analysis based on human leukocyte antigen (HLA)-B*27 positive patients and healthy subjects, results indicated that there were four significant positive associations between 2DL5, 2DS4, 2DS5, 3DS1 polymorphisms and susceptibility to AS in HLA-B*27-positive patients; a significant negative association of 3DL1 in HLA-B*27-positive patients was found.

CONCLUSIONS

While 2DS1, 2DS5, and 3DS1 polymorphisms increased AS risk, 2DL2 and 2DS2 polymorphisms were associated with reduced AS susceptibility.

Putative role of KIR3DL1/3DS1 alleles and HLA-Bw4 ligands with end stage renal disease and long term renal allograft survival

BACKGROUND

Killer immunoglobulin receptors (KIR) are highly polymorphic in nature. KIR3DL1/3DS1 genes are known to affect HLA-B antigen binding affinity causing natural killer (NK) cell inhibition, which results into successful renal transplantation. In this study we have examined whether alleles of KIR3DL1/3DS1 play any role in changing the binding affinity with HLA-Bw4 antigen and if so then how are they associated with long term renal allograft survival. We have also evaluated plausible association of KIR3DL1 with HLA-A23/A24/A32 with renal pathophysiology.

MATERIALS AND METHODS

KIR3DL1/3DS1 allelic diversity was examined in 501 renal transplant cases and 507 controls. PCR-SSP was used to determine the incidence of KIR3DL1/3DS1 genes and HLA class-I antigens. KIR3DL1/3DS1 alleles were determined by sequencing. Expression at transcription level for KIR3DL1/3DS1 genes was evaluated in the presence of HLA-Bw4. Different statistical analyses were performed using SPSS v 22.0. p≤0.05 was considered significant. Sequence based variant effect was predicted using Variant Effect Predictor. To evaluate whether variation in KIR3DL1 and HLA interaction changes the binding affinity structure based effect prediction was carried out using MutaBind and BindProf software.

RESULTS

For KIR3DL1*0010101, no-risk and low mRNA expression was seen among antibody mediated acute rejection (ABMR) and chronic rejection (CR) cases. Whereas, 3DS1*01301, 3DL1*00401, and 3DL1*00402 showed susceptibility and elevated mRNA expression with ABMR and CR. Two mutations c.320C>T (rs143159382) and c.911G>T (rs35974949), present in alleles 3DL1*00402 and 3DL1*00401 were predicted to be deleterious. Reduced renal allograft survival was observed for individuals possessing KIR3DL1*00401-HLA-Bw4+. In relation to HLA-A locus no significance was observed with ESRD, ABMR, and CR.

DISCUSSION

The experimental and computational data corroborated with each other suggesting susceptibility for renal allograft in presence of 3DL1*00402 and 3DL1*00401 alleles.

KIR2DL2 and KIR2DS2 as genetic markers to the methotrexate response in rheumatoid arthritis patients

CONTEXT

Disease Modifying Anti-Rheumatic Drugs (DMARDs) are aimed to interfere with rheumatoid arthritis (RA) progression and reduce the joint damage; however, not all patients respond alike. Killer-cell immunoglobulin-like receptors (KIR) and their ligands, human leucocyte antigen class I (HLA-I), have been associated with RA pathology; therefore, KIR and HLA genes may influence the treatment response.

MATERIALS AND METHODS

We evaluated the association of KIR genotype and their ligands HLA-C genes with the response to DMARDs in RA patients. We included 69 patients diagnosed with RA and 82 healthy individuals as the reference group. KIR and HLA-C genotyping was performed using SSP-PCR. RA patients were assessed at baseline and under treatment at 6 and 12 months; subsequently classified as responders and non-responders in each time period. We evaluated the association between DMARD response and genes using statistical analysis by using Fisher exact test with Bonferroni correction; results were regarded as statistically significant at p < 0.05.

RESULTS

Significant difference was observed in gene frequencies of patients and the reference group, KIR2DL2 was associated with RA (p = 0.031, OR = 2.119). We also observed an association between KIR2DS2 and the response to methotrexate (MTX), moreover, the combination KIR2DL2+/KIR2DS2+ was more frequent in responders to MTX (p = 0.043).

DISCUSSION AND CONCLUSIONS

In our results, responders and non-responders to DMARDs showed KIR2DS2 and KIR2DL2 different gene frequencies, therefore, these genes could be used as response predictors to DMARDs treatment. Thus, these genes were also associated with disease severity, as well as the treatment response possibly by the immunoregulatory function of NK cells.

Association of NKG2D gene variants with susceptibility and severity of rheumatoid arthritis

NKG2D (KLRK1) is a C-type lectin receptor present on natural killer (NK) cells, γδ, CD8⁺ and CD4⁺ T cells. Upon ligand binding, NKG2D mediates activatory and co-stimulatory signals to NK cells and activated CD4⁺ T cells, respectively. Polymorphisms in NKG2D predispose to infectious diseases, cancer, transplantation and autoimmune disorders. We studied the influence of this NK receptor polymorphism on predisposition to and modification of the disease phenotype in patients with rheumatoid arthritis (RA). Eight different single nucleotide polymorphisms (SNP) in the NKG2 gene were genotyped in 236 patients with RA and 187 controls using Taqman 5' nuclease assays. NKG2D genotype/allele frequency did not differ between patients and controls. Subgroup analysis showed that the frequency of A allele of NKG2D9 and T allele of NKG2D10 was significantly higher in patients with deformities (a marker of severe disease) [11 versus 5%, Pc = 0·03, odds ratio (OR) = 2·44, 95% confidence interval (CI) = 1·09-5·98 and 10 versus 4%, Pc = 0·04, OR = 2·45, 95% CI = 1·05-6·39, respectively], while the frequency of alleles G of NKG2D9 and A of NKG2D10 was greater in patients without deformities (Pc = 0·03, OR = 0·41, 95% CI = 0·17-0·91 and Pc = 0·04, OR = 0·41, 95% CI = 0·16-0·96). Similar trends of association were observed with deforming phenotype of RA in female patients and deforming young onset RA subgroups. Haplotype analysis revealed that the frequency of haplotype G-C-A-G-A-T-C-C was higher in patients than in controls (12 versus 8%, P = 0·04, OR = 1·61, 95% CI = 1·01-2·55), suggesting that it may predispose to RA. Our study suggests that the NKG2D gene polymorphisms may modify the risk of development and severity of RA.

Killer Cell Immunoglobulin-Like Receptor (KIR) Genotype Distribution in Familial Mediterranean Fever (FMF) Patients

BACKGROUND Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disease predominantly affecting Mediterranean populations. The gene associated with FMF is the MEFV gene, which encodes for a protein called pyrin. Mutations of pyrin lead to uncontrolled attacks of inflammation, and subclinical inflammation continues during attack-free intervals. Killer cell immunoglobulin-like receptor (KIR) genes encode HLA class I receptors expressed by NK cells. The aim this study was to look for immunogenetic determinants in the pathogenesis of FMF and find out if KIR are related to susceptibility to disease or complications like renal amyloidosis. MATERIAL AND METHODS One hundred and five patients with FMF and 100 healthy individuals were involved in the study. Isolated DNA from peripheral blood was amplified by sequence specific PCR probes and analyzed by Luminex for KIR genotypes. Fisher Exact test was used to evaluate the variation of KIR gene distribution. RESULTS All patients and healthy controls expressed the framework genes. An activator KIR gene, KIR2DS2, was significantly more frequent in FMF patients (p=0.036). Renal amyloidosis and presence of arthritis were not associated with KIR genes and genotype. KIR3DL1 gene was more common in patients with high serum CRP (p=0.016). CONCLUSIONS According to our findings, we suggest that presence of KIR2DS2, which is an activator gene for NK cell functions, might be related to the autoinflammation in FMF. The potential effect of KIR genes on amyloidosis and other clinical features requires studies with larger sample sizes.

Genetic associations of killer immunoglobulin like receptors and class I human leukocyte antigens on childhood acute lymphoblastic leukemia among north Indians

BACKGROUND

Molecular interactions between KIRs and their cognate HLA class-I ligands, play a central role in the regulation of natural killer (NK) cell responses in malignancies. We aimed to determine the role of KIR genes and their HLA ligands in genetic predisposition of childhood acute lymphoblastic leukemia (ALL).

METHODS

Genotyping of 16 KIR genes, along with HLA class-I groups C1/C2 and Bw4 super-type ligands, was carried-out in 137 childhood ALL cases and 274 healthy controls.

RESULTS

We observed an increased incidence of activating KIRs namely; 2DS2 (OR=2.23, p=<0.001), 2DS3 (OR=1.74, p=0.011), 3DS1 (OR=2.22, p=<0.001), 2DS5 (OR=2.10, p=0.001), 2DS1 (OR=4.42, p=<0.001) and 2DS4 (OR=2.88, p=<0.001) genes in childhood ALL cases compared to controls. Frequency of BB genotype that possess 2-6 activating KIR genes was predominant in cases compared to controls (OR=2.55, p=<0.001). KIR-receptor/HLA-ligand combinations analysis revealed a moderate risk of almost 2-fold for activating KIR-ligand combinations namely; KIR2DS1-HLAC2, KIR2DS2-HLAC1 and KIR3DS1-HLABw4 in childhood ALL cases.

CONCLUSION

Our data suggests the role for KIR genes and their HLA ligands in aetiology of childhood ALL.

Association between KIR gene polymorphisms and rheumatoid arthritis susceptibility: A meta-analysis

OBJECTIVES

The results of studies on association between KIR (killer cell immunoglobulin-like receptors) polymorphisms and susceptibility to RA (rheumatoid arthritis) are inconsistent. To comprehensively evaluate the effect of KIR polymorphisms on the risk of RA, a meta-analysis was carried out.

METHODS

The Web of Science, PubMed, the Chinese Biomedical Database (CBM) and Chinese National Knowledge Infrastructure (CNKI) databases were systematically searched to select studies on the association between KIR polymorphisms and RA. The odds ratio (OR) with 95% confidence interval (95%CI) was obtained.

RESULTS

Nine qualified case-control studies were included in this meta-analysis. The results showed there were two positive associations of 2DL1, 2DS1 (OR2DL1=2.20, 95%CI=1.20-4.01, Praw=0.01, PFDR=0.03; OR2DS1=1.84, 95%CI=1.19-2.85, Praw=0.006, PFDR=0.018) and one negative association of 2DL3 (OR2DL3=0.42, 95%CI=0.22-0.79, Praw=0.006, PFDR=0.018) with susceptibility to RA in East Asians, but not in Caucasians.

CONCLUSION

The current meta-analysis provides evidence that 2DL3 might be a potential protective factor and 2DL1, 2DS1 might be risk factors for RA in East Asians but not in Caucasians.

Role of viruses and bacteria-virus interactions in autoimmunity

A potential role for viral and bacterial-viral interactions in the pathogenesis of autoimmune disease has been long recognized. Recently, intensive investigation has begun to decipher interactions between specific microbes with the host that contribute toward autoimmunity. This work has primarily focused on known viral and bacterial pathogens. A major challenge is to determine the role of bacteria that are typically considered as commensals as well as chronic viruses. Furthermore, equally challenging is to prove causality given the potential complexity of microbe-microbe interactions. Important initial contributions to this field have shown that specific interactions of microbes with hosts that contain a background of genetic susceptibility can play a role in autoimmune pathogenesis. In this review, we describe principles of immune tolerance with a focus on its breakdown during pathogenic as well as commensal relationships between the host and the microbial world.