Interleukin 6 gene polymorphisms are associated with systemic lupus erythematosus in Koreans

Association of interleukin-6 promoter polymorphism with rheumatoid arthritis: a meta-analysis with trial sequential analysis

OBJECTIVES

The association of interleukin-6 (IL-6) -174G/C (rs1800795) and IL-6 -572G/C (rs1800796) single-nucleotide polymorphism (SNP) with the risk of acquiring rheumatoid arthritis (RA) was inconsistent among previous studies. This paper aims to investigate the association between IL-6 promoter polymorphism with RA in different ethnics.

METHODS

Relevant studies were searched using Medline and Google Search engines; STATA software was used to perform the meta-analysis. Pooled odds ratios (OR) were calculated to estimate the potential genetic associations. Subgroup analysis and sensitivity analysis were applied to explore the sources of heterogeneity. Lastly, we used TSA (trial sequential analysis) software to verify the reliability of meta-analysis results.

RESULTS

A total of 18 studies were included, involving 8116 subjects (3820 RA patients and 4296 controls). We found a tendency to associate RA with the IL-6 -174G/C allele in Asians (C vs G: OR = 4.56, 95% CI = 1.85-11.23; P < 0.001); with IL-6 -572G/C genotype or allele frequencies, there was no statistical differences between RA patients and controls (P > 0.05). TSA results indicate that the current meta-analysis can draw conclusions.

CONCLUSIONS

IL-6-174G/C gene polymorphism were associated with increased risk of RA in Asians, but not in Caucasians. There was no association between IL-6 -572G/C gene polymorphism and the risk of RA. Key Points • Although the association between interleukin-6 (IL-6) promoter polymorphism and rheumatic arthritis (RA) has been discussed in the previous meta-analysis, their conclusions are inconsistent. • In this study, trial sequential analysis (TSA) was introduced into the meta-analysis, and the following two important conclusions were confirmed: (1) IL-6-174G/C gene polymorphism was associated with increased risk of RA in Asians, but not in Caucasians. (2) There was no association between IL-6 -572G/C gene polymorphism and the risk of RA.

Association of recipient and donor interleukin 6 polymorphisms 174 and 597 with outcome after allogeneic hematopoietic stem cell transplantation in children

Purpose

The success of allogeneic hematopoietic stem cell transplantation (HSCT) is compromised by complications such as infection, relapse, and graft-versus-host disease (GVHD). The investigation of non-HLA immunogenetics, particularly of cytokines, could identify predictors of an unfavorable outcome after allogeneic HSCT. In this study, we examined the impact of single nucleotide polymorphisms (SNPs) within the promoter region of interleukin 6 (IL6) on the development of GVHD after pediatric allogeneic HSCT.

Methods

In this retrospective analysis, we included 320 pediatric patients with a median age of 10 years who underwent an allogeneic HSCT and their respective donors. We used TaqMan real-time polymerase chain reaction to analyze the SNPs IL6-174 (G/C) and IL6-597 (G/A). The IL6-174 polymorphism was examined in 300 recipients and 295 donors. The IL6-597 polymorphism was analyzed in 299 recipients and 296 donors. We investigated the influence of the IL6-174 and IL6-597 polymorphisms on overall survival, event-free survival, relapse incidence, transplant-related mortality, and the occurrence of GVHD.

Results

G polymorphism at position 174 of the recipient IL6 gene was associated with a higher incidence of acute GVHD (GG vs. GC/CC; P = 0.024). Patients with IL6-597 GG genotype developed acute GVHD more frequently than individuals with an A allele (GG vs. GA vs. AA; P = 0.013). IL6-174 GG homozygous recipients had a more frequent occurrence of chronic GVHD (GG vs. GC/CC; P = 0.049). We observed a significant increased risk of chronic GVHD in recipients with IL6-597 GG genotype (GG vs. GA vs. AA; P = 0.043). Polymorphisms of donors did not affect the incidence of acute GVHD and chronic GVHD. In multivariate analysis, the IL6-174 and IL6-597 SNPs were independent significant risk factors for acute GVHD (P = 0.030; P = 0.007, respectively) as well as for chronic GVHD (P = 0.045; P = 0.015, respectively). In addition, older age at time of transplantation turned out to be a significant risk factor for chronic GVHD (P = 0.003).

Conclusion

Our study identified the IL6-174 and IL6-597 GG genotypes of pediatric allogeneic HSCT recipients as genetic risk factors for the development of acute GVHD and chronic GVHD. After evaluations in further studies, these findings could implicate the adjustment of prophylactic measures to reduce the occurrence of acute GVHD and chronic GVHD.

The Network of Inflammatory Mechanisms in Lupus Nephritis

Several signaling pathways are involved in the progression of kidney disease in humans and in animal models, and kidney disease is usually due to the sustained activation of these pathways. Some of the best understood pathways are specific proinflammatory cytokine and protein kinase pathways (e.g., protein kinase C and mitogen-activated kinase pathways, which cause cell proliferation and fibrosis and are associated with angiotensin II) and transforming growth factor-beta (TGF-β) signaling pathways (e.g., the TGF-β signaling pathway, which leads to increased fibrosis and kidney scarring. It is thus necessary to continue to advance our knowledge of the pathogenesis and molecular biology of kidney disease and to develop new treatments. This review provides an update of important findings about kidney diseases (including diabetic nephropathy, lupus nephritis, and vasculitis, i.e., vasculitis with antineutrophilic cytoplasmic antibodies). New disease targets, potential pathological pathways, and promising therapeutic approaches from basic science to clinical practice are presented, and the blocking of JAK/STAT and TIM-1/TIM-4 signaling pathways as potential novel therapeutic agents in lupus nephritis is discussed.

The Association between Interleukin-6 Gene Polymorphisms and Risk of Systemic Lupus Erythematosus: A Meta-analysis with Trial Sequential Analysis

BACKGROUND

Molecular epidemiological studies have sought associations between interleukin-6 (IL-6) polymorphisms and the risk of systemic lupus erythematosus (SLE); however, the results are controversial. Therefore, we conducted a meta-analysis with trial sequential analysis to evaluate a more accurate estimation of the associations.

METHODS

Published literatures reporting the relationships of two IL-6 polymorphisms (G-174C and G-572C) and SLE risk were retrieved from electronic databases such as PubMed and EMBASE. The most appropriate genetic model was chosen for each polymorphism. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Trial sequential analysis (TSA) was introduced to assess the information size and the positive results.

RESULTS

With 17 studies (2780 cases and 3100 controls) included, a dominant association (CC+GC vs. GG) was suggested for G-174C polymorphism, and compared with the GG genotype, the CC+GC genotype of G-174C was associated with a decreased SLE risk (OR = 0.71; 95% CI = 0.56-0.88, P =.02). No association was found for G-572C under all genetic models (e.g. OR and 95%CI for CC+GC vs. GG: 0.89, 0.73-1.08, P =.22). Subgroup analyses indicated that SLE risk decreased in G-174C polymorphism by subgroups of Caucasian population, publications after 2010, studies with high quality, and studies complied with Hardy-Weinberg equilibrium (HWE). TSA suggested that the sample sizes used for G-572C were insufficient.

CONCLUSION

We found that the minor allele C of IL6G-174C polymorphism is a protective factor in SLE. Further studies with a larger sample size are needed to confirm the null association for G-572C.

Association of interleukin-6 gene promoter polymorphism with acne vulgaris and its severity

BACKGROUND

Acne vulgaris (AV) is an inflammatory disorder with a possible genetic background. Different cytokines and mediators are involved in its pathogenesis.

AIM

Our aim was to investigate the interleukin (IL)-6 572 polymorphism in patients with AV and its relation to patient sex and acne severity.

METHODS

In total, 30 patients with acne and 20 healthy controls (HCs) were enrolled. The Global Acne Grading System was used to assess acne severity. The IL-6 572 gene promoter polymorphism was assessed using the PCR-restriction fragment length polymorphism method.

RESULTS

There was a significantly higher association of IL-6 572 variants genotypes in patients with acne (93%) compared with the HC group (45%) (P < 0.001), with a higher incidence of the IL-6 572 CC polymorphism in patients with acne. A significant difference (P < 0.001) between C and G alleles in patients vs. HCs was detected. There were no significant associations between the IL-6 572 variant genotypes and either patient sex or AV severity.

CONCLUSION

IL-6 gene promoter polymorphism might have a role in AV susceptibility but it is not related to AV severity.

Genetic polymorphisms of interleukin 6 and interleukin 10 in Egyptian patients with systemic lupus eythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease. Cytokine gene polymorphisms play an important role in SLE. Thus, this study aimed to investigate the associations between interleukin 6 (IL-6) and interleukin 10 (IL-10) promoter single-nucleotide polymorphisms (SNPs) and their susceptibility to SLE and the implications for plasma levels. We genotyped IL-6-174G/C (rs1800795) using mutagenically separated polymerase chain reaction (MS-PCR) and IL-10-1082G/A (rs1800896) and -819C/T (rs1800871) using sequence specific primer polymerase chain reaction (SSP-PCR) in 100 Egyptian patients and 119 controls. The plasma levels of IL-6 and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA). There was significant increase in the frequency of IL-6 (-174) GG genotype ( P < 0.05) and G allele ( P < 0.01) compared to controls. A significant increase in the distribution of IL-10 (-1082G/A) GG ( P < 0.05) and AA ( P < 0.05) genotypes and a significant reduction in the frequency of GA genotype ( P < 0.05) was found in SLE patients. The mean serum concentration of IL-6 ( P < 0.001) and IL-10 ( P < 0.001) was significantly elevated in SLE patients compared to healthy controls. There was no  significant association of the most common clinical findings and IL-6 and IL-10 gene polymorphisms in SLE patients. In conclusion, our preliminary study indicated that both GG genotype and G allele of IL-6 (-174G/C) could be considered as risk factors for SLE. In addition, the polymorphisms at IL-10 (-1082 G/G and AA) may play a role in SLE susceptibility in Egyptian patients. Larger prospective studies are needed to confirm our findings.

Association of the interleukin-6 polymorphisms with systemic lupus erythematosus: a meta-analysis

BACKGROUND

Interleukin (IL)-6, an important proinflammatory cytokine, plays a potential pathological role in systemic lupus erythematosus (SLE). Studies on the relationship of IL-6 gene polymorphisms with SLE are inconclusive. The aim of this study was to estimate the relationship more precisely.

METHODS

The databases of PubMed and Web of Science updated to 30 August 2014 were retrieved. Meta-analysis was conducted using allelic contrast, dominant, recessive and homozygote contrast models. Fifteen studies were included in this study and ethnicity-specific meta-analysis was performed on European, Iranian and Asian populations.

RESULTS

Analysis for the IL-6-174 G/C polymorphism under all models except the homozygote contrast model indicated an association in the overall population (allelic contrast model: odds ratio (OR) 1.428, 95% confidence interval (CI) 1.124-1.812, dominant model: OR 1.382, 95% CI 1.037-1.842, recessive model: OR 1.610, 95% CI 1.158-2.240, homozygote contrast model: OR 1.759, 95% CI 0.989-3.127), as well as in European individuals under all four genetic models (allelic contrast model: OR 1.557, 95% CI 1.155-2.098, dominant model: OR 1.699, 95% CI 1.203-2.400, recessive model: OR 1.506, 95% CI 1.176-1.930, homozygote contrast model: OR 2.118, 95% CI 1.103-4.065). Analysis for the IL-6-572 G/C polymorphism indicated significant association in overall ethnicities under the recessive model (OR 1.491, 95% CI 1.104-2.014), but not under other models or in Asian individuals. In addition, significant association between the IL-6-174 G/C polymorphism and discoid skin lesions and antinuclear antibodies (ANAs) were found under the allelic contrast model and recessive model, respectively (discoid skin lesions: OR 2.271, 95% CI 1.053-4.895; ANAs: OR 2.244, 95% CI 1.141-4.416).

CONCLUSION

This meta-analysis provides evidence of the association between the IL-6 polymorphism and the risk of SLE, hinting that the IL-6-174 G/C and IL-6-572 G/C polymorphisms may play a role in SLE susceptibility.

Liver X receptors alpha gene (NR1H3) promoter polymorphisms are associated with systemic lupus erythematosus in Koreans

Introduction

Liver X receptors are established sensors of lipid and cholesterol homeostasis. Recent studies have reported that these receptors are involved in the regulation of inflammation and immune responses. We attempted to identify single nucleotide polymorphisms (SNPs) of the NR1H3 gene associated with the susceptibility to systemic lupus erythematosus (SLE).

Methods

SNPs were genotyped using SNaPSHOT assay in 300 Korean patients with SLE and 217 normal controls (NC), and in replication samples (160 SLE patients and 143 NC). Also, the functional effects of NR1H3 gene promoter polymorphisms were analyzed using a luciferase assay, real-time polymerase chain reaction, B cell proliferation assay and an electrophoretic mobility shift assay.

Results

We identified five polymorphisms: -1851 T > C (rs3758673), -1830 T > C (rs3758674), -1003 G > A (new), -840 C > A (rs61896015) and -115 G > A (rs12221497). There was a significant and reproducible difference in the -1830 T > C, -1003 G > A and -115 G > A polymorphisms between the SLE and the NC. Luciferase activity of the structure containing -1830 C was less enhanced compared to the structure containing -1830 T in basal, GW3965 and T0901317 treated Hep3B cells (P = 0.009, P = 0.034 and P <0.001, respectively). Proliferation of the -1830 TC type was increased compared to the -1830 TT type in basal, GW3965 and T0901317 treated B cells from SLE patients (P = 0.011, P = 0.040 and P = 0.017, respectively). Transcription factor GATA-3 preferentially bound the -1830 T allele in the promoter.

Conclusions

NR1H3 genetic polymorphisms may be associated with disease susceptibility and clinical manifestations of SLE. Specifically, -1830 T > C polymorphism within NR1H3 promoter region may be involved in regulation of NR1H3 expression.

The association between interleukin-6 polymorphisms and rheumatoid arthritis: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether the functional interleukin-6 (IL-6) promoter -174 G/C and -572 G/C polymorphisms confer susceptibility to rheumatoid arthritis (RA) in ethnically different populations.

METHODS

Meta-analysis was conducted on the associations between these IL-6 polymorphisms and RA.

RESULTS

A total of nine studies involving 3,851 subjects (RA 2,053 and controls 1,798) were considered in this study and ethnicity-specific meta-analysis was performed on European subjects. In all study subjects, meta-analysis revealed a trend toward to an association between RA and the IL-6 -174 G allele (odds ratio [OR] = 0.699, 95 % confidence interval [CI] = 0.463-1.054, p = 0.088). Stratification by ethnicity indicated a significant association between RA and the IL-6 -174 G/C polymorphism in Europeans using the dominant (OR = 0.329, 95 % CI = 0.155-0.699, p = 0.004) and recessive (OR = 0.823, 95 % CI = 0.679-0.997, p = 0.047) models. Meta-analysis of the IL-6 -572 G/C polymorphism showed no association between RA and the IL-6 -572 G allele in all study subjects (OR = 1.641, 95 % CI = 0.613-4.397, p = 0.324).

CONCLUSIONS

This meta-analysis shows that the IL-6 -174 G/C polymorphism may confer susceptibility to RA in Europeans.

A meta-analysis of the effects of interleukin-6 -174 G>C genetic polymorphism on acute graft-versus-host disease susceptibility

BACKGROUND

The interleukin-6 (IL-6) -174 G>C genetic polymorphism has been implicated to play an important role in acute graft-versus-host disease (aGVHD). However, previous studies have yielded inconclusive results as to its role in patient susceptibility to aGVHD, and no study to date has systematically analyzed this polymorphism.

OBJECTIVE

A meta-analysis of the published evidence was conducted to estimate the true effect of the IL-6 -174 G>C genetic polymorphism in allogeneic hematopoietic stem cell transplantation (alloHSCT) patients and donors on the risk of aGVHD.

METHODS

Seven cohort studies, comprising 1287 recipient and donor pairs, were included after eliminating 62 studies that met the following exclusion criteria: irrelevant studies other than cohort studies, without sufficient data, and with overlapping data. Although interstudy heterogeneity existed, most studies were conducted in the United States or Europe and included adult patients with hematologic disease who received alloHSCT from human leukocyte antigen-matched or identical sibling donors. The effect of the polymorphism on aGVHD risk (grades I-IV, II-IV, and III-IV) was estimated from odds ratios with 95% confidence intervals for the dominant genetic model and recessive model, respectively.

RESULTS

Patients who received grafts from donors with the IL-6 G allele experienced more frequent grade I-IV aGVHD (odds ratio = 3.304 [95% confidence interval, 1.456-7.494]) and grade II-IV aGVHD (odds ratio = 1.738 [95% CI, 1.006 - 3.001]).

CONCLUSIONS

To our knowledge, this is the first meta-analysis to evaluate the relation between a non-human leukocyte antigen gene polymorphism and the risk of aGVHD. Our meta-analysis combined the results of several studies and demonstrated that the donor IL-6 G allele is associated with an increased risk of grades I-IV and II-IV aGVHD.

Treatment of systemic lupus erythematosus: new advances in targeted therapy

Treatment for systemic lupus erythematosus (SLE) has traditionally been restricted to broad-based immunosuppression, with glucocorticoids being central to care. Recent insights into lupus pathogenesis promise new, selective therapies with more favorable side effect profiles. The best example of this is belimumab, which targets the B cell cytokine BLyS and has now received Food and Drug Administration (FDA) approval for its use in SLE. Strategies targeting other cytokines, such as interleukin 6 (IL-6) and interferon (IFN)-α, are also on the horizon. Blockade of costimulatory interactions between immune cells offers another opportunity for therapeutic intervention, as do small molecule inhibitors that interfere with cell signaling pathways. We review here the current strategies for SLE treatment, with particular focus on therapies now in active pharmaceutical development. We will also discuss new understandings in lupus pathogenesis that may lead to future advances in therapy.

The association between interleukin-6 polymorphisms and systemic lupus erythematosus: a meta-analysis

The aim of this study was to determine whether the functional interleukin-6 (IL-6) promoter -174 G/C and -572 G/C polymorphisms confer susceptibility to systemic lupus erythematosus (SLE) in ethnically different populations. Meta-analysis was conducted on the associations between the IL-6 polymorphisms and SLE using; 1) allele contrast, 2) the recessive model, 3) the dominant model, and 4) the additive model. A total of 11 studies were considered in this study, and ethnicity-specific meta-analysis was performed on European and Asian populations. Meta-analysis of the IL-6 -174 G/C polymorphism showed an association between SLE and the IL-6 -174 G allele in all study subjects (odds ratio (OR) = 1.344, 95% confidence interval (CI) = 1.052-1.718, p = 0.018). Furthermore, stratification by ethnicity indicated an association between the IL-6 -174 G allele and SLE in Europeans (OR = 1.264, 95% CI = 1.037-1.541, p = 0.020). Meta-analysis of the IL-6 -572 G/C polymorphism revealed that an association was found between SLE and the IL-6 -572 G/C polymorphism using the recessive model, but ethnicity-specific meta-analysis revealed no association between SLE and the IL-6 -572 G/C polymorphism in Asians. In conclusion, this meta-analysis demonstrates that the IL-6 -174 G/C polymorphism may confer susceptibility to SLE in Europeans, but that the IL-6 -572 G/C polymorphism is not associated with susceptibility to SLE in Asians.

Tolerogenic function of Blimp-1 in dendritic cells

Blimp-1 has been identified as a key regulator of plasma cell differentiation in B cells and effector/memory function in T cells. We demonstrate that Blimp-1 in dendritic cells (DCs) is required to maintain immune tolerance in female but not male mice. Female mice lacking Blimp-1 expression in DCs (DCBlimp-1(ko)) or haploid for Blimp-1 expression exhibit normal DC development but an altered DC function and develop lupus-like autoantibodies. Although DCs have been implicated in the pathogenesis of lupus, a defect in DC function has not previously been shown to initiate the disease process. Blimp-1(ko) DCs display increased production of IL-6 and preferentially induce differentiation of follicular T helper cells (T(FH) cells) in vitro. In vivo, the expansion of T(FH) cells is associated with an enhanced germinal center (GC) response and the development of autoreactivity. These studies demonstrate a critical role for Blimp-1 in the tolerogenic function of DCs and show that a diminished expression of Blimp-1 in DCs can result in aberrant activation of the adaptive immune system with the development of a lupus-like serology in a gender-specific manner. This study is of particular interest because a polymorphism of Blimp-1 associates with SLE.

Depletion of autoreactive plasma cells and treatment of lupus nephritis in mice using CEP-33779, a novel, orally active, selective inhibitor of JAK2

Accumulating evidence suggests that autoreactive plasma cells play an important role in systemic lupus erythematosus (SLE). In addition, several proinflammatory cytokines promote autoreactive B cell maturation and autoantibody production. Hence, therapeutic targeting of such cytokine pathways using a selective JAK2 inhibitor, CEP-33779 (JAK2 enzyme IC(50) = 1.3 nM; JAK3 enzyme IC(50)/JAK2 enzyme IC(50) = 65-fold), was tested in two mouse models of SLE. Age-matched, MRL/lpr or BWF1 mice with established SLE or lupus nephritis, respectively, were treated orally with CEP-33779 at 30 mg/kg (MRL/lpr), 55 mg/kg or 100 mg/kg (MRL/lpr and BWF1). Studies included reference standard, dexamethasone (1.5 mg/kg; MRL/lpr), and cyclophosphamide (50 mg/kg; MRL/lpr and BWF1). Treatment with CEP-33779 extended survival and reduced splenomegaly/lymphomegaly. Several serum cytokines were significantly decreased upon treatment including IL-12, IL-17A, IFN-α, IL-1β, and TNF-α. Anti-nuclear Abs and frequencies of autoantigen-specific, Ab-secreting cells declined upon CEP-33779 treatment. Increased serum complement levels were associated with reduced renal JAK2 activity, histopathology, and spleen CD138(+) plasma cells. The selective JAK2 inhibitor CEP-33779 was able to mitigate several immune parameters associated with SLE advancement, including the protection and treatment of mice with lupus nephritis. These data support the possibility of using potent, orally active, small-molecule inhibitors of JAK2 to treat the debilitative disease SLE.

Association between variable number tandem repeats within the 3' flanking region of the interleukin-6 gene and systemic lupus erythematosus in Korean patients

Variable number tandem repeat (VNTR) polymorphism located in the 3' flanking region of the interleukin-6 (IL-6) gene was examined in Koreans with systemic lupus erythematosus (SLE). We identified 15 VNTR alleles (K1 to K15) in the 3' flanking region by Genescan analysis. The VNTR K8 allele, a 648-base pair (bp) allele, was most commonly found in Koreans, being present in 74.8% of the SLE patients and 70.3% of the normal controls. The VNTR K9 (642 bp) allele was associated with susceptibility to SLE. In addition, the VNTR K9 was significantly associated with leukopenia (p = 0.048), thrombocytopenia (p = 0.020), and elevated C-reactive protein (p = 0.019). These data suggest that the VNTR K9 in the 3' flanking region of the IL-6 gene may be associated with disease susceptibility and the clinical phenotypes of SLE.