Association between IL-37 and Systemic Lupus Erythematosus Risk.

Interleukin-37 (IL-37) is an anti-inflammatory cytokine. In our former study, we found increased plasma IL-37 levels in systemic lupus erythematosus (SLE) patients. However, relationship between IL-37 levels and clinical laboratory characteristics of SLE patients has not been elucidated. In addition, association of IL37 gene polymorphism with SLE risk needs to be discussed. A group of 580 individuals (220 SLE patients and 360 healthy controls) in a Southern Chinese Han population were recruited. Plasma IL-37 levels were evaluated using enzyme-linked immunosorbent assay (ELISA). Four single-nucleotide polymorphisms (rs3811047, rs2723186, rs2723176 and rs4364030) of IL37 gene were genotyped. Relationship of IL-37 expression, IL37 gene polymorphisms and clinical characteristics was discussed. We found that plasma levels of IL-37 were negatively associated with SLE disease activity index (SLEDAI) (rs = -0.352, P = .001), and were higher in less active patients compared with active patients (P = .003). Decreased levels of IL-37 were found in SLE patients with discoid rash when compared to patients who did not have this symptom (P < .001). Plasma IL-37 levels were significantly lower in patients with hypocomplementemia comparing to those without this feature (P = .009). Levels of IL-37 in SLE with positive proteinuria were lower than patients with negative proteinuria (P = .046). Furthermore, allele distribution of rs2723186, rs4364030 between SLE cases and healthy individuals was significantly different (P = .001, P = .010, respectively). Genotype of rs4364030 was different between SLE cases and controls (P = .015). Haplotype analysis revealed that the frequency of haplotype CG (rs2723176 (C) +rs2723186 (G)) was higher in SLE, as compared with healthy individuals (P = .002). In conclusion, the plasma levels of IL-37 were related to SLE severity, and IL37 gene polymorphisms (rs2723186, rs2723176 and rs4364030) may associate with SLE susceptibility.

IL-38: A novel cytokine in systemic lupus erythematosus pathogenesis.

IL-38 is a newly identified cytokine that belongs to the IL-1 family. In our previous study, we found elevated plasma levels of IL-38 in patients with systemic lupus erythematosus (SLE). However, the clear relationship of IL-38 expression in plasma, peripheral blood mononuclear cells (PBMCs) and clinical and laboratory features needs elucidation. Additionally, we evaluated the possible role of IL-38 in regulating production of inflammatory cytokines in PBMCs in vitro. A pristane-induced murine lupus model was used to further demonstrate the effects of IL-38 on cytokines in vivo and discuss the significance of IL-38 in lupus development. The results showed that mRNA expression of IL-38 in PBMCs of patients with SLE was elevated compared with volunteers, and expression of IL-38 in both plasma and PBMCs was strongly related to clinical features, such as haematuria and proteinuria, and correlated with a SLEDAI score. Plasma levels of TNF-α, IL-1ß, IL-6 and IL-23 were elevated in patients with SLE and were related to plasma levels of IL-38. In vitro, PBMCs of patients with SLE stimulated with IL-38 showed a decreased expression of the four inflammatory cytokines compared with PBMCs of patients without treatment. Interestingly, IL-38 administration in lupus mice significantly reduced the development of lupus, such as reduced proteinuria, improved histological examinations of the kidneys and down-regulated inflammatory cytokines. In conclusion, IL-38 may suppress synthesis of pro-inflammatory cytokines and therefore regulate lupus pathogenesis.

Gene polymorphisms and serum levels of TL1A in patients with rheumatoid arthritis.

Recent findings showed elevated expression of tumor necrosis factor (TNF)-like ligand 1A (TL1A) in rheumatoid arthritis (RA) patients and arthritis mice. However, whether TL1A gene polymorphisms may correlate with RA susceptibility needs to be discussed. This case-control study was performed on 350 RA patients and 556 healthy subjects to identify TL1A genetic variants (rs3810936, rs6478109, and rs7848647) and their possible association with TL1A levels, susceptibility to and severity of RA. Odds ratio and 95% confidence interval were calculated to represent the correlation between TL1A polymorphisms and RA. The TL1A serum levels were evaluated. Results showed that frequencies of TC, TT + TC genotypes of rs3810936, rs7848647 in RA patients were significantly lower in RA patients compared with controls. Patients with C allele showed more severe disease course (disease activity index: erythrocyte sedimentation rate, rheumatoid factor) than in carriers of T allele. However, the allele or genotype frequencies of rs6478109 were not associated with RA. In addition, TL1A genetic variants conferred higher TL1A levels in RA patients compared with controls. In conclusion, these findings indicated an association between TL1A rs3810936, rs7848647 variation and the susceptibility of RA in a sample of Chinese individuals, and TL1A may correlate with severity of RA.

Association between TL1A gene polymorphisms and systemic lupus erythematosus in a Chinese Han population.

Our previous studies showed elevated tumor necrosis factor-like ligand 1 aberrance (TL1A) expression in systemic lupus erythematosus (SLE). However, TL1A polymorphisms with SLE susceptibility remain to be elucidated. In addition, we made meta-analysis to evaluate the relationship of TL1A polymorphisms and autoimmune diseases owing to inconsistent results. The present research was carried out by 404 SLE, 150 primary Sjogren's syndrome (pSS) patients, and 574 healthy individuals. Three TL1A polymorphisms (rs3810936, rs6478109, rs7848647) were genotyped using TaqMan genotyping assay. Then, the meta-analysis was performed by collecting the present case-control study and previously published research. Results showed that genotypes of rs3810936, rs7848647 were different between SLE patients and healthy controls, whereas no significant association was observed in the three polymorphisms and pSS patients. Genotypes distribution of rs6478109, rs7848647 were strongly related to lupus nephritis within SLE (p = 0.004, p = 0.011), respectively. Moreover, combined meta-analysis consisted of ten comparative research involving 4,305 patients and 5,600 controls. An association between autoimmune diseases and rs6478109 polymorphism was found. Our findings indicate that gene polymorphisms (rs3810936, rs7848647) of TL1A might correlate with lupus.

Serum levels and gene polymorphisms of angiopoietin 2 in systemic lupus erythematosus patients.

This study aimed to discuss association between serum Angiopoietin2 (Ang2) levels, Ang2 gene polymorphisms and systemic lupus erythematosus (SLE) susceptibility. It was carried out by 235 SLE, 342 other inflammatory autoimmune diseases patients and 380 healthy individuals. Serum Ang2 levels was examinated by ELISA, and Ang2 rs12674822, rs1823375, rs1868554, rs2442598, rs3739390 and rs734701 polymorphisms were genotyped using KASP. Increased Ang2 concentrations in SLE patients were observed compared with healthy controls and patients with other inflammatory autoimmune diseases. For allelic contrast, except for rs1823375 (P = 0.058) and rs2442598 (P = 0.523), frequencies of alleles for other polymorphisms were significantly different between SLE patients and controls. Genotypes for rs12674822 (TT), rs1868554 (TT, TA and TT+TA), rs734701 (TT) were negatively correlated with SLE susceptibility (OR = 0.564 for rs12674822; OR = 0.572, OR = 0.625, OR = 0.607 for rs1868554; OR = 0.580 for rs734701). Patients carrying rs1868554 T allele and rs3739390 G allele were more likely to develop hematuria (P = 0.039; P = 0.003). The G allele frequencies of rs12674822 and rs2442598 were higher in SLE patients with proteinuria (P = 0.043; P = 0.043). GC genotype frequency of rs3739390 was higher in patients with ds-DNA (+) (P = 0.024). In summary, SLE had increased serum Ang2, which may be a potential biomarker, and the polymorphisms correlated with SLE.

Association of MBL2 gene polymorphisms and systemic lupus erythematosus susceptibility: A meta-analysis.

OBJECTIVES: Mannose binding lectin (MBL) gene single nucleotide polymorphisms have been associated with systemic lupus erythematosus (SLE) risk with inconsistent results. This study aimed to explore whether MBL2 A\B, A\C, A\D, A\O, L\H and Y\X polymorphisms affected SLE susceptibility. METHODS: A meta-analysis was performed on 20 studies, containing allelic contrast, additive, dominant and recessive models. Odds ratio (OR) was calculated to reflect the effect of association. RESULTS: A total of 64 pooled comparisons were conducted, including 7194 SLE patients and 7401 healthy controls. The meta-analysis inducted a significant association between allele B and SLE (OR = 0.766, 95% CI = 0.681-0.862, P < .001). The genotype BB in the additive model and AB + BB in the recessive model both reduced the risk of SLE (OR = 0.611, 95% CI = 0.422-0.882, P = .009; OR = 0.806, 95% CI = 0.688-0.944, P = .008). Regarding A\O polymorphisms, results revealed statistical differences in allelic contrast, additive model and recessive models (OR = 0.826, 95% CI = 0.732-0.931, P = .002; OR = 0.737, 95% CI = 0.557-0.977, P = .034 and OR = 0.793, 95% CI = 0.683-0.921, P = .002, respectively). As for L\H, meta-analysis revealed that allele H and genotype HH both decreased SLE susceptibility in allelic contrast and dominant models (OR = 1.463, 95% CI = 1.097-2.007, P = .018; OR = 1.383, 95% CI = 1.124-1.701, P = .002). Stratification by ethnicity indicated that allele H related to SLE in European populations (OR = 0.736, 95% CI = 0.617-0.879, P = .001), and the recessive model correlated with SLE in Asians (OR = 0.808, 95% CI = 0.667-0.979, P = .03). CONCLUSION: The present study suggests that A\B and A\O polymorphisms were associated with SLE susceptibility, and the allele H may be a protective factor in SLE.

Gene polymorphisms and serum levels of sVEGFR-1 in patients with systemic lupus erythematosus.

Correlation between soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) concentration, VEGFR1 gene polymorphisms and systemic lupus erythematosus (SLE) risk remains unclear. The present case-control study comprised 254 SLE patients, 385 other rheumatic diseases patients and 390 healthy controls. Serum levels of sVEGFR-1 were detected by enzyme-linked immunosorbent assay. Seven VEGFR1 genetic variants (rs2296188, rs9943922, rs2296283, rs7324510, rs9554322, rs9582036, rs9554320) were genotyped by KASP. Serum levels of sVEGFR-1 were up-regulated in SLE and positively correlated with disease activity. Furthermore, serum sVEGFR-1 presented a distinctive elevation in SLE in comparison with other rheumatic diseases. Frequencies of allele T of rs2296283 and allele G of rs9554322 were significant lower in SLE patients (P = 0.003, P = 0.004). Frequencies of genotypes TT of rs2296188 and rs2296283 were declined in patients compared with healthy controls (P = 0.039, P = 0.033). CC genotype of rs7324510 and rs9582036 was negatively correlated with SLE risk (OR = 0.538, OR = 0.508). Distribution of GG, GC, GG + GC genotypes of rs9554322 were different between SLE patients and healthy controls (P = 0.027, P = 0.036, P = 0.010). Moreover, frequency of TC genotype of rs7324510 was higher in SLE patients with lupus headache (χ2 = 9.924, P = 0.039) and frequency of TC genotype of rs9943922 was lower in patients with cylindruriain (χ2 = 7.589, P = 0.026). Frequencies of allele C of rs7324510 and allele T of rs9943922 were decreased in SLE patients with cylindruria and hypocomplementemia, respectively (χ2 = 4.195, P = 0.041, χ2 = 3.971, P = 0.046). However, frequency of allele C of rs9554322 was increased in SLE patients with pyuria (χ2 = 11.702, P = 0.001). In addition, SLE patients carrying GG, GC, CC genotypes for rs9554322 had higher levels of serum sVEGFR-1. In conclusion, serum sVEGFR-1 was elevated in SLE patients and may be a disease marker. VEGFR1 gene polymorphisms related to risk of SLE in a Chinese Han population.

Elevated expression of interleukin-37 in patients with rheumatoid arthritis.

AIM: This study aims to discuss plasma and messenger RNA (mRNA) levels of interleukin (IL)-37 in rheumatoid arthritis (RA) patients and evaluate the potential of plasma IL-37 as a biomarker for RA. METHOD: Plasma IL-37 levels and IL-37 mRNA relative concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). We discussed the association of IL-37 levels and clinical, laboratory parameters in RA patients in a training cohort. Plasma IL-37 levels were tested for discriminatory capacity by receiver operating characteristic (ROC) curve analysis. We then validated plasma IL-37 expression in a cohort of 598 patients (230 RA, 107 systemic lupus erythematosus [SLE], 100 osteoarthritis [OA], 62 gout, 51 primary Sjögren's syndrome [pSS], 48 ankylosing spondylitis [AS]). RESULTS: Both plasma levels of IL-37 and mRNA levels of IL-37 were elevated in RA patients compared to those in healthy controls in the training cohort, and there was a good diagnostic ability to predict RA (area under the curve [AUC] = 0.97). Plasma IL-37 levels were significantly related to Disease Activity Score of 28 joints - erythrocyte sedimentation rate (DAS28-ESR) (rs  = 0.459, P < 0.001). The levels of IL-37 mRNA were related to plasma IL-37 levels (rs  = 0.642, P < 0.001), DAS28-ESR (r = 0.641, P < 0.001) and C-reactive protein (rs  = 0.603, P < 0.001). In the validation cohort, when plasma IL-37 in RA patients compared with that in SLE, OA, gout, pSS and AS patients, the AUC was 0.86, 0.87, 0.91, 0.87, 0.92, respectively. CONCLUSION: IL-37 expression was increased in RA patients, and correlated with disease activity. IL-37 may be a biomarker for the diagnosis of RA.

Association of IRF5 rs2004640 polymorphism and systemic lupus erythematosus: A meta-analysis.

BACKGROUND: This study aimed to discuss the relationship between interferon regulatory factor (IRF)5 gene rs2004640 T/G polymorphism and systemic lupus erythematosus (SLE) susceptibility. METHODS: A meta-analysis was calculated on the association between rs2004640 polymorphism and SLE by allelic contrast (T vs G), additive model (TT vs GG), recessive model (TT vs TG + GG) and dominant model (TT + TG vs GG). RESULTS: A total of 28 comparisons were identified, including 11 228 SLE cases and 14 374 controls. Meta-analysis revealed a significant association between allele T and SLE in overall populations (odds ratio [OR] = 1.393, 95% CI: 1.276-1.522, P < 0.001). Stratification by ethnicity indicated strong associations between T allele and SLE in Asians, Europeans and Latin Americans (OR = 1.256, 95% CI: 1.073-1.469, P = 0.004; OR = 1.338, 95% CI: 1.080-1.659, P = 0.008; OR = 1.853, 95% CI: 1.488-2.308, P < 0.001). Results also showed significant associations between the additive model and SLE in all subjects and Asians (OR = 1.999, 95% CI: 1.442-2.771, P < 0.001; OR = 1.544, 95% CI: 1.009-2.362, P < 0.045). In addition, we found significant associations between the dominant model and SLE in all populations and Asians (OR = 1.521, 95% CI: 1.257-1.841, P < 0.001; OR = 1.270, 95% CI: 1.136-1.421, P < 0.001). A marginal association was detected between the recessive mode and SLE in overall subjects (OR = 1.480, 95% CI: 1.022-2.144, P = 0.038). CONCLUSION: The current study suggested that individuals carrying rs2004640 T allele correlated with a high risk of SLE, and the IRF5 rs2004640 polymorphism was associated with SLE susceptibility.

Biology of IL-36 Signaling and Its Role in Systemic Inflammatory Diseases.

Interleukin (IL)-36 is a member of the IL-1 superfamily and includes three agonists (IL-36α, IL-36ß, and IL-36γ) and an antagonist (IL-36Ra). IL-36 agonists bind to heterodimeric receptor complexes. Then, the heterotrimer complexes signal via intracellular functional domains, binding to downstream signaling proteins and inducing inflammatory responses. In this review, we summarized the current knowledge about the biological role of IL-36 and its correlation with systemic inflammatory diseases. The information collected will help to increase the understanding of the potential of IL-36 and may give clues for developing novel therapeutic strategies.