Polymorphism of IL37 gene as a protective factor for autoimmune thyroid disease

Interleukin-37: associations of plasma levels and genetic variants in gout

OBJECTIVES

IL-37 is an anti-inflammatory cytokine involved in inflammatory and autoimmune diseases. We aimed to investigate the association between IL-37 genetic variants, IL-37 plasma levels, and various clinical phases of gout.

METHODS

The study included a control group with no history of primary hyperuricemia/gout, (n = 50), asymptomatic hyperuricemia (n = 74), intercritical gout (n = 200), acute gouty flare (n = 18), and chronic tophaceous gout (n = 30). Plasma IL-37 was analysed using enzyme-linked immunosorbent assay. All coding regions and intron-exon boundaries of IL-37 and exons 1-5 were amplified and sequenced.

RESULTS

Plasma levels of IL-37 were significantly higher in asymptomatic hyperuricemic (p = 0.045), intercritical gout (p = 0.001), and chronic tophaceous gout (p = 0.021) cohorts when compared to control group. The levels of IL-37 in patients with acute gouty flare were comparable to control group (p = 0.061). We identified 15 genetic variants of IL-37: eight intron (rs2708959, rs2723170, rs2708958, rs2723169 rs2466448, rs3811045, rs3811048, rs2708944) and seven non-synonymous allelic variants (rs3811046, rs3811047, rs2708943, rs2723183, rs2723187, rs2708947, rs27231927), of which rs2708959 showed an over-presentation in gouty and acute flare cohorts (p = 0.003 and 0.033, respectively) compared to European population (minor allelic frequency MAF = 0.05) but not in control and hyperuricemic cohorts (p/MAF = 0.17/0.08 and 0.71/0.05, respectively).. On the contrary, rs3811045, rs3811046, rs3811047, and rs3811048 were underrepresented among individuals with tophaceous gout (MAF = 0.57) compared to European MAF 0.70-0.71, but not compared to the control cohort (MAF = 0.67).

CONCLUSIONS

We demonstrated the up-regulation of IL-37 levels across the clinical phases of gout: asymptomatic hyperuricemia, intercritical, and chronic tophaceous gout compared to control. Moreover, 15 genetic variants of IL-37 were identified and their associations with the clinical variants of gout were evaluated.

Cross-Talk between the Cytokine IL-37 and Thyroid Hormones in Modulating Chronic Inflammation Associated with Target Organ Damage in Age-Related Metabolic and Vascular Conditions

Chronic inflammation is considered to be the main mechanism contributing to the development of age-related metabolic and vascular conditions. The phases of chronic inflammation that mediate the progression of target organ damage in these conditions are poorly known, however. In particular, there is a paucity of data on the link between chronic inflammation and metabolic disorders. Based on some of our own results and recent developments in our understanding of age-related inflammation as a whole-body response, we discuss the hypothesis that cross-talk between the cytokine IL-37 and thyroid hormones could be the key regulatory mechanism that justifies the metabolic effects of chronic tissue-related inflammation. The cytokine IL-37 is emerging as a strong natural suppressor of the chronic innate immune response. The effect of this cytokine has been identified in reversing metabolic costs of chronic inflammation. Thyroid hormones are known to regulate energy metabolism. There is a close link between thyroid function and inflammation in elderly individuals. Nonlinear associations between IL-37 and thyroid hormones, considered within the wider clinical context, can improve our understanding of the phases of chronic inflammation that are associated with target organ damage in age-related metabolic and vascular conditions.

Interleukin-37 gene polymorphism and susceptibility to coronavirus disease 19 among Iraqi patients

Coronavirus disease 19 (COVID-19) is a highly contagious respiratory viral infection. Dysregulated immune response is an important feature of disease, and cytokines are among the most important mediators of dysregulated immunity. Interleukin-37 (IL-37) is one such cytokine and studies have indicated its role in pathogenesis of COVID-19. However, IL37 gene polymorphisms have not been identified in patients with COVID-19. Therefore, this case-control study (100 patients and 100 controls) was performed to understand the role six single nucleotide polymorphisms of IL37 gene (SNPs: rs3811042, rs3811043, rs2466449, rs3811045, rs3811046 and rs3811047) in susceptibility to COVID-19 among cases with severe disease. These polymorphisms were identified by Sanger DNA sequencing. Results revealed that TG genotype of rs3811046 showed a significantly increased frequency in patients compared to controls (61.0 vs. 38.0%; odds ratio [OR] = 2.55; 95% confidence interval [CI] = 1.45–4.50; probability [p] = 0.002; corrected p [pc] = 0.01). GA genotype of rs3811047 also showed an increased frequency in patients but the pc-value was not significant (39.0 vs. 24.0%; OR = 2.02; 95% CI = 1.10–3.71; p = 0.033; pc = 0.165). Haplotype analysis revealed a significantly increased frequency of the haplotype G-C-A-T-T-A (in the order: rs3811042, rs3811043, rs2466449, rs3811045, rs3811046 and rs3811047) in COVID-19 patients compared to controls (0.055 vs. 0.006; OR = 10.23; 95% CI = 1.53–68.14; p = 0.003; pc = 0.03). In conclusion, the study indicated that two variants of IL37 gene (rs3811046 and rs3811047) may be associated with susceptibility to COVID-19 among Iraqi population.

Association of the IL-37 Polymorphisms with Transaminases and Alkaline Phosphatase Levels in Premature Coronary Artery Disease Patients and Healthy Controls. Results of the Genetics of Atherosclerotic (GEA) Mexican Study

Interleukin 37 (IL-37) is an anti-inflammatory cytokine expressed in foam cells located in the atherosclerosis plaques. The present study aimed to evaluate the association of the IL-37 polymorphisms with premature coronary artery disease (pCAD), cardiovascular risk factors, metabolic parameters, and levels of liver enzymes. Three IL-37 polymorphisms (rs6717710, rs2708961, and rs2708947) were determined in 1161 patients with pCAD and 951 healthy controls. IL-37 polymorphisms were not associated with the presence of pCAD. The association of the polymorphisms with cardiovascular risk factors, metabolic parameters, and levels of liver enzymes was evaluated independently in pCAD and healthy controls. In pCAD patients, under different models, the rs6717710 was associated with low risk of having elevated alkaline phosphatase (ALP) (p_additive = 0.020; p_dominant = 0.02; p_heterozygous = 0.04; p_codominant1 = 0.040). On the other hand, in healthy controls, the rs6717710 was associated with low risk of having elevated levels of alanine aminotransferase (ALT) (p_additive = 0.04, p_recessive = 0.01, p_codominant2 = 0.01) and aspartate aminotransferase (AST) (p_additive = 0.02, p_dominant = 0.02). The IL-37 polymorphisms were not associated with the risk of pCAD. In pCAD patients, the rs6717710 was associated with low risk of having elevated ALP levels, whereas in controls was associated with low risk of having elevated ALT and AST levels.

TGF-β1 +869T/C (rs1982073) gene polymorphism and susceptibility to rheumatoid arthritis: Updated systematic review and meta-analysis

Rheumatoid arthritis (RA) is a complex autoimmune disease that affects about 1% of the world's population. The conclusions about the relationship between TGF gene polymorphism and the risk of RA are still inconsistent. Therefore, we performed a meta-analysis to re-evaluate the relationship between TGF-β1 T869C gene polymorphism and the risk of rheumatoid arthritis.

METHOD

We performed a systematic electronic search in PubMed, Embase, Elsevier, Web of Science, Cochrane Library, Medline and China National Knowledge Infrastructure database (up to August 2020). In the subgroup analysis, we divide the research into three groups: Asian, European and Mediterranean, The combined OR and 95%CI of the five models (allele model, homozygous model, heterozygous model, dominant model, recessive model) were calculated, respectively.

RESULTS

15 case-control studies (14 articles) were involved in this meta-analysis, including 2103 cases and 2143 healthy controls. In the overall analysis, it showed that there may be an significant association between TGF-β1+869T/C polymorphism and RA sensitivity (allele model, T vs. C: OR=1.444, 95% CI=1.171-1.782, P=0.001; homozygous model, TT vs. CC: OR=1.910, 95% CI=1.322-2.761, P=0.001; heterozygous model, CT vs. CC: OR=1.558, 95% CI=1.179-2.059,P=0.002; dominant model, TT+CT vs. CC: OR= 1.742, 95% CI=1.303-2.329, P=0.001; recessive model, TT vs. CT+CC: OR=1.400, 95% CI= 1.058-1.852, P=0.018).However, the results of ethnic subgroup analysis indicated that rs1982073 was not associated with RA risk in Europeans(allele model, T vs. C: OR=0.993, 95% CI=0.849-1.162, P=0.931, I² <0.1%, P>0.1).

CONCLUSION

In summary, our meta-analysis showed that the rs1982073 T allele does not increase RA susceptibility in Europeans.

No association of genetic variants in TLR4, TNF-α, IL10, IFN-γ, and IL37 in cytomegalovirus-positive renal allograft recipients with active CMV infection-Subanalysis of the prospective randomised VIPP study

Background

Cytomegalovirus (CMV) infection is amongst the most important factors complicating solid organ transplantation. In a large prospective randomized clinical trial, valganciclovir prophylaxis reduced the occurrence of CMV infection and disease compared with preemptive therapy in CMV-positive renal allograft recipients (VIPP study; NCT00372229). Here, we present a subanalysis of the VIPP study, investigating single nucleotide polymorphisms (SNPs) in immune-response-related genes and their association with active CMV infection, CMV disease, graft loss or death, rejection, infections, and leukopenia.

Methods

Based on literature research ten SNPs were analyzed for TLR4, three for IFN-γ, six for IL10, nine for IL37, and two for TNF-α. An asymptotic independence test (Cochran-Armitage trend test) was used to examine associations between SNPs and the occurrence of CMV infection or other negative outcomes. Statistical significance was defined as p<0.05 and Bonferroni correction for multiple testing was performed.

Results

SNPs were analyzed on 116 blood samples. No associations were found between the analyzed SNPs and the occurrence of CMV infection, rejection and leukopenia in all patients. For IL37 rs2723186, an association with CMV disease (p = 0.0499), for IL10 rs1800872, with graft loss or death (p = 0.0207) and for IL10 rs3024496, with infections (p = 0.0258) was observed in all patients, however did not hold true after correction for multiple testing.

Conclusion

The study did not reveal significant associations between the analyzed SNPs and the occurrence of negative outcomes in CMV-positive renal transplant recipients after correction for multiple testing. The results of this association analysis may be of use in guiding future research efforts.

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) (r_s = -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.

Validation in a Brazilian population of gene markers of periodontitis previously investigated by GWAS and bioinformatic studies

BACKGROUND

Bioinformatic tools and genome-wide association studies (GWAS) have led to comprehensive identification of single nucleotide polymorphisms (SNPs) associated with periodontitis in diverse populations. Here we aimed to detect and validate the association of seven SNPs as genetic markers of susceptibility to periodontitis in a Brazilian population.

METHODS

This case-control study assessed complete periodontal parameters of 714 subjects with periodontal status classified as healthy/mild periodontitis (n = 356) and moderate/severe periodontitis (n = 358). Genotyping for rs187238, rs352140, rs1360573, rs2521634, rs3811046, rs3826782, and rs7762544 SNPs were evaluated. Genetic-phenotype associations, and sex or smoking effects of SNPs on periodontitis were tested using multiple logistic regressions adjusted for covariates.

RESULTS

The rs2521634-AA (close to NPY gene) presented increased risk for severe periodontitis (OR = 2.34; 95% CI = 1.19-4.59). The rs3811046-GG (IL37 gene) demonstrated increased risk for moderate periodontitis (OR = 2.58; 95% CI = 1.28-5.18). Higher risk for moderate periodontitis was found in male with rs7762544-AG close to NCR2 gene. The rs352140-TT in the TLR9 gene proved to be associated with lower risk to severe periodontitis in men. The rs2521634-AA was associated with higher percentage of interproximal probing pocket depth (P = .004).

CONCLUSIONS

This is the first evidence of validation in a Brazilian population of genetic markers of periodontitis previously investigated by GWAS and bioinformatics studies. SNPs in the NPY, IL37, and NCR2 genes were associated with susceptibility to moderate or severe periodontitis; whereas the TLR9 marker was associated with lower chance to develop severe periodontitis. Those SNPs had sex- and smoking-habit-specific effects on periodontitis; reinforcing the genetic profile predisposing to periodontitis.

Circulating concentration of interleukin-37 in Helicobacter pylori-infected patients with peptic ulcer: Its association with IL-37 related gene polymorphisms and bacterial virulence factor CagA

The immunopathologic responses play a major role in the development of H. pylori (HP)-related gastrointestinal diseases. IL-37 is an anti-inflammatory cytokine with potent suppressive effects on innate and adaptive immune responses. Here, we investigated the IL-37 levels and two single nucleotide polymorphisms (SNPs) including rs3811047 and rs2723176 in IL-37 gene in HP-infected peptic ulcer (PU) patients to identify any relationship. Three groups, including 100 HP-infected PU patients, 100 HP-infected asymptomatic (AS) subjects and 100 non-infected healthy control (NHC) subjects were enrolled to study. Serum IL-37 levels and the genotyping at rs3811047 and rs2723176 were determined using ELISA and SSP-PCR methods, respectively. Significantly higher IL-37 levels were observed in PU patients compared with AS and NHC groups (P < 0.0001). In both PU and AS groups, the CagA⁺ HP-infected participants displayed higher IL-37 levels compared with those infected with CagA^- strains (P < 0.0001). There were significant differences between PU, AS and NHC groups regarding the distribution of genotypes and alleles at rs3811047 and rs2723176 SNPs. The genotype GG and allele G at IL-37 rs3811047 SNP, and the genotype CC and allele C at IL-37 rs2723176 SNP more frequently expressed in PU patients than total healthy subjects (AS + NHC groups) and were associated with an increased risk of PU development (genotype GG: RR = 3.08, P < 0.009; allele G: RR = 2.94, P < 0.01; genotype CC: RR = 5, P < 0.01; and allele C: RR = 5.0, P < 0.02, respectively). The PU patients with allele A at IL-37 rs2723176 SNP expressed higher amounts of IL-37 compared with patients carried allele C at the same position (P < 0.05). In AS carriers and NHC individuals, the IL-37 levels in subjects carried genotype AA or allele A at IL-37 rs2723176 SNP were higher than those carried genotype CC or allele C at the same location (P < 0.01 and P < 0.02 for AS group; P < 0.0001 and P < 0.001 for NHC subjects, respectively). The increased IL-37 levels may be considered as a valuable marker of PU development in HP-infected individuals. The SNPs rs3811047 and rs2723176 were associated with PU development. The CagA status of HP and IL-37 rs2723176 SNP may affect the IL-37 levels.

Genetic Variants in TMEM39A Gene Are Associated with Autoimmune Thyroid Diseases

Transmembrane protein 39A (TMEM39A) gene polymorphisms have been related to various autoimmune diseases, but the relationship between TMEM39A polymorphisms and autoimmune thyroid disease (AITD) remains unknown. This study was aimed at investigating whether the polymorphisms of the TMEM39A were associated with AITD in the Chinese Han population. A case-control study was performed in a total of 906 AITD patients and 744 healthy controls. Four single nucleotide polymorphisms, including rs1132200, rs12492609, rs2282175, and rs7629750, in TMEM39A were examined by polymerase chain reaction-ligase detection reaction. We found that the allele T of rs12492609 in TMEM39A was associated with AITD and Hashimoto's thyroiditis (HT) (p = 0.023; p = 0.028 respectively). Compared with controls, the frequency of haplotype CCA in AITD patients was higher than that in controls (p = 0.036), but the frequency of haplotype CTA in AITD and HT patients was lower than that in controls (p = 0.046; p = 0.047 respectively). In addition, the frequency of allele A at rs7629750 in AITD patients with onset age ≤18 years old was higher than that in AITD patients with onset age ≥19 (p = 0.046). Further, there was an obvious difference in the genotype distributions of rs12492609 and rs7629750 between HT patients with hypothyroidism and those without hypothyroidism (p = 0.034 and p = 0.023, respectively). Our study first reveals that the polymorphisms of the TMEM39A gene are associated with the susceptibility to AITD, especially for early-onset AITD and HT with hypothyroidism.

The MAGI2 gene polymorphism rs2160322 is associated with Graves' disease but not with Hashimoto's thyroiditis

PURPOSE

Autoimmune thyroid diseases (AITDs) are chronic organ-specific autoimmune disorders, predominantly including Graves' disease (GD), and Hashimoto's thyroiditis (HT). This study aimed to investigate whether single-nucleotide polymorphisms (SNPs) in MAGI2 and MAGI3 gene contributed to the etiology of AITDs.

METHODS

We conducted a case-control study including 1001 patients with AITDs (625 GD, 376 HT) and 846 healthy controls. Subgroup analyses in GD and HT were also performed.

RESULTS

The genotypes of rs2160322 in MAGI2 showed a borderline association with AITDs (P = 0.048), and they had a strong correlation with GD (P = 0.012). The frequency of the minor allele G of rs2160322 was significantly higher in the GD patients than in the controls (P = 0.027; OR 1.91; 95% CI 1.020-1.391), especially for GD females (P = 0.008; OR 1.304; 95% CI 1.072-1.587), and those who had positive family history (P = 0.011; OR 1.412; 95% CI 1.083-1.843). For genetic model analysis, the recessive model and homozygous model of rs2160322 showed significant associations with AITDs (P = 0.009; P = 0.019) and GD (P = 0.004; P = 0.005). Nevertheless, our study could not identify any relationship between these SNPs and HT. Due to the low mutation rate of rs1343126 in MAGI3, we were unable to obtain a credible conclusion on its association with AITDs.

CONCLUSIONS

Our study identified that MAGI2 rs2160322 was strongly associated with GD susceptibility. The potential dysfunction of tight junction proteins and aberrant epithelial barrier caused by abnormal MAGI2 expression may be a novel mechanism of GD.

Association between IL-37 gene polymorphisms and risk of HBV-related liver disease in a Saudi Arabian population

Interleukin-37 (IL-37) has recently been recognized as a strong anti-inflammatory cytokine having anti-tumor activity against hepatocellular carcinoma (HCC) in hepatitis B virus (HBV)-infected patients. HCC is a typical inflammation-related cancer, and genetic variations within the IL-37 gene may be associated with the risk of HBV infection. Identification of the allelic patterns that genetically have a high disease risk is essential for the development of preventive diagnostics for HBV-mediated liver disease pathogenesis. In this study, we aimed to investigate the association between single nucleotide polymorphisms (SNPs) within the IL-37 gene and disease sequelae associated with HBV infection. We genotyped ten IL-37 SNPs in 1274 patients infected with HBV and 599 healthy controls from a Saudi Arabian population. Among the selected SNPs, two SNPs (rs2723175 and rs2708973) were strongly associated with HBV infection, and six SNPs (rs2723176, rs2723175, rs2723186, rs364030, rs28947200, rs4392270) were associated with HBV clearance, comparing healthy controls and HBV infected-patients respectively. A suggestive association of rs4849133 was identified with active HBV surface antigen (HBsAg) carrier and HBV-related liver disease progression. In conclusion, our findings suggest that variations at the IL-37 gene may be useful as genetic predictive risk factors for HBV infection and HBV-mediated liver disease progression in the Saudi Arabian population.

IRF7 Gene Variations Confer Susceptibility to Autoimmune Thyroid Diseases and Graves' Ophthalmopathy

The objective of this study was to investigate whether IRF7 polymorphisms are associated with autoimmune thyroid diseases (AITDs). We selected three single nucleotide polymorphisms (SNPs) of IRF7, namely, rs1061501, rs1131665, and rs1061502 for genotyping using PCR-based ligase detection reaction (LDR) method in a total of 1659 participants (592 with Graves' disease, 297 with Hashimoto's thyroiditis, and 770 healthy controls). Gene-disease and genotype-clinical phenotype associations were evaluated for the three SNPs. Our results showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in AITD patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.017, OR = 1.968; allele G: P = 0.018, OR = 1.946; rs1061502: AG genotype: P = 0.029, OR = 1.866; allele G: P = 0.031, OR = 1.847). Subgroup analysis also showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in Graves' disease patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.015, OR = 2.074; allele G: P = 0.016, OR = 2.048; rs1061502: AG genotype: P = 0.034, OR = 1.919; allele G: P = 0.035, OR = 1.898). Furthermore, the allele G frequency of rs1061501 was associated with Graves' ophthalmopathy (P = 0.035, OR = 1.396). No significant difference in IRF7 polymorphisms was found between Hashimoto's thyroiditis patients and controls. Our study has revealed for the first time that IRF7 is a susceptibility gene for AITD, especially for Graves' disease and Graves' ophthalmopathy.

Polymorphisms in Autophagy-Related Gene IRGM Are Associated with Susceptibility to Autoimmune Thyroid Diseases

Background

To date, studies have shown that polymorphisms in an autophagy-related gene, IRGM, are linked with different diseases, especially autoimmune diseases. The present study aimed to examine the roles of IRGM polymorphisms in autoimmune thyroid diseases (AITD).

Methods

Three polymorphisms in IRGM gene (rs10065172, rs4958847, and rs13361189) were genotyped in 1569 participants (488 with Graves' disease, 292 with Hashimoto's thyroiditis, and 789 healthy controls) using PCR-based ligase detection reaction method. Gene-disease associations were evaluated for the three SNPs.

Results

T allele of rs10065172, A allele of rs4958847, and C allele of rs13361189 were all higher in Graves' disease patients than controls, and the ORs were OR = 1.207 (P = 0.022), OR = 1.207 (P = 0.027), and OR = 1.200 (P = 0.027), respectively. After adjusting for sex and age, rs10065172 and rs13361189 were still associated with GD under both the allele model and dominant model, and the adjusted ORs for rs10065172 were 1.20 (P = 0.033) and 1.33 (P = 0.024), while the adjusted ORs for rs13361189 were 1.19 (P = 0.042) and 1.33 (P = 0.026), respectively. No significant difference was found between Hashimoto's thyroiditis patients and controls. Haplotype analysis found that CTA frequency was distinguishingly higher in Graves' disease patients (OR = 1.195, P = 0.030). The frequency of TCG haplotype was distinguishingly lower in AITD and Graves' disease patients (OR = 0.861, P = 0.044; OR = 0.816, P = 0.017).

Conclusions

Our study reveals IRGM as a susceptibility gene of AITD and Graves' disease for the first time.

Association between interleukin 37 (rs3811047) polymorphism and multiple autoimmune diseases in a Chinese population: A PRISMA-compliant meta-analysis

OBJECTIVE

Emerging evidence suggests that interleukin 37 (IL-37) plays an important role in the pathogenesis of several autoimmune diseases (ADs), but the correlations are still unclear. We conducted a meta-analysis to explore whether IL-37 gene (rs3811047) polymorphism was associated with susceptibility to multiple ADs in a Chinese population.

METHODS

Relevant studies were searched in the PubMed, Embase, Chinese National Knowledge Infrastructure, and Chinese Wangfang databases up to August 31, 2017. Odds ratio (OR) and its 95% confidence interval (95% CI) was used to estimate the strength of the association in different genetic models. The results of fixed or random models were adopted according to the heterogeneity. Publication bias and sensitive analysis were also performed to evaluate the reliability of results.

RESULTS

A total of 3161 patients and 4078 controls from 6 studies were included in this meta-analysis. Pooling all data together, a significant association between IL-37 gene (rs3811047 A/G) polymorphism and susceptibility to ADs in the Chinese population was found in all 4 genetic models (allelic model A vs G: OR = 0.73 95% CI = 0.67∼0.79; recessive model AA + AG vs GG: OR = 0.72, 95% CI = 0.65∼0.79; dominant model AA vs AG + GG: OR = 0.59, 95% CI = 0.45∼0.77; homozygous model AA vs GG: OR = 0.55, 95% CI = 0.42∼0.72). No heterogeneity and publication bias was detected in all models. Sensitive analysis indicated that all of the positive results are reliable.

CONCLUSION

The IL- 37 (rs3811047) polymorphism contributes to the development of ADs in a Chinese population.

Potential role of IL-37 in atherosclerosis

IL-37 is a member of the IL-1 family, but unlike most other members of this family of cytokines, it has wide-ranging anti-inflammatory properties. Initially shown to bind IL-18 binding protein and prevent IL-18-mediated inflammation, its known role has been expanded to include distinct pathways, both intracellular involving the transcription factor Smad3, and extracellular via binding to the orphan receptor IL-1R8. A number of recent publications investigating the role of IL-37 in atherosclerosis and ischemic heart disease have revealed promising therapeutic value of the cytokine. Although research concerning the role of IL-37 and its mechanism in atherosclerosis is relatively scant, there are a number of well-known atherosclerotic processes that this cytokine can mediate with the potential of modulating the disease progression itself. This review will probe in detail the effects of IL-37 on important pathological processes such as inflammation, dysregulated lipid metabolism, and apoptosis, by analyzing existing data as well as exploring the potential of this cytokine to influence these properties.

Functional Analysis of the rs774872314, rs116171003, rs200231898 and rs201107751 Polymorphisms in the Human RORγT Gene Promoter Region

RAR-related orphan receptor gamma RORγT, a tissue-specific isoform of the RORC gene, plays a critical role in the development of naive CD4+ cells into fully differentiated Th17 lymphocytes. Th17 lymphocytes are part of the host defense against numerous pathogens and are also involved in the pathogenesis of inflammatory diseases, including autoimmune disorders. In this study, we functionally examined four naturally occurring polymorphisms located within one of the previously identified GC-boxes in the promoter region of the gene. The single nucleotide polymorphisms (SNPs) rs774872314, rs116171003 and rs201107751 negatively influenced the activity of the RORγT promoter in a gene reporter system and eliminated or reduced Sp1 and Sp2 transcription factor binding, as evidenced by the electrophoretic mobility shift assay (EMSA) technique. Furthermore, we investigated the frequency of these SNPs in the Polish population and observed the presence of rs116171003 at a frequency of 3.42%. Thus, our results suggest that polymorphisms within the RORγT promoter occurring at significant rates in populations affect promoter activity. This might have phenotypic effects in immune systems, which is potentially significant for implicating pathogenetic mechanisms under certain pathological conditions, such as autoimmune diseases and/or primary immunodeficiencies (e.g., immunoglobulin E (IgE) syndrome).

Association of IL-37 gene polymorphisms with susceptibility to tuberculosis in Saudi subjects

Tuberculosis (TB) is one of the most common infectious diseases worldwide. IL-37, a novel member of the IL-1 family, has anti-inflammatory activity. Various cytokine genes polymorphisms are reportedly associated with susceptibility to TB infection. However, an association between genetic variations in the IL-37 gene and susceptibility to TB infection has not been investigated. The aim of this case-control study was therefore to identify such an association in Saudi subjects, in which five single-nucleotide polymorphisms (SNPs) in the IL-37 gene were assessed. Serum concentrations of IL-37 were evaluated using ELISA, and genetic variants genotyped by multiplex PCR and ligase detection reaction. It was found that the C/C genotype of rs2723176 (-6962 A/C) occurs significantly more frequently in patients with active TB and that the C allele of this SNP is associated with TB. In addition, the C allele of rs2723176 SNP was associated with high circulating concentrations of IL-37. However, the genotype and allele frequency of the other four SNPs (rs3811046, rs3811047, rs2723186 and rs2723187) were not significantly associated with TB infection. In conclusion, the present data suggest that rs2723176 SNP of IL-37 is involved in the development of TB infection. Furthermore, high circulating concentrations of IL-37 may have a negative effect on protective immunity against TB infection.

IL-37 Confers Protection against Mycobacterial Infection Involving Suppressing Inflammation and Modulating T Cell Activation

Interleukin-37 (IL-37), a novel member of the IL-1 family, plays fundamental immunosuppressive roles by broadly reducing both innate inflammation and acquired immunity, but whether it is involved in the pathogenesis of tuberculosis (TB) has not been clearly elucidated. In this study, single nucleotide polymorphism (SNP) analysis demonstrated an association of the genetic variant rs3811047 of IL-37 with TB susceptibility. In line with previous report, a significant elevated IL-37 abundance in the sera and increased expression of IL-37 protein in the peripheral blood mononuclear cells (PBMC) were observed in TB patients in comparison to healthy controls. Moreover, release of IL-37 were detected in either macrophages infected with Mycobacterium tuberculosis (Mtb) or the lung of BCG-infected mice, concurrent with reduced production of proinflammatory cytokines including IL-6 and TNF-α. Furthermore, in contrast to wild-type mice, BCG-infected IL-37-Tg mice manifested with reduced mycobacterial burden and tissue damage in the lung, accompanied by higher frequency of Th1 cell and less frequencies of regulatory T cells and Th17 cells in the spleen. Taken together, our findings demonstrated that IL-37 conferred resistance to Mtb infection possibly involving suppressing detrimental inflammation and modulating T cell responses. These findings implicated that IL-37 may be employed as a new molecular target for the therapy and diagnosis of TB.

Variants of Interleukin-22 Gene Confer Predisposition to Autoimmune Thyroid Disease

As there are no previous studies on the interleukin-22 (IL-22) variants in autoimmune thyroid disease (AITD), the present study aimed to explore the association between polymorphisms of IL-22 and the predisposition to AITD. The study had 975 AITD patients, including 639 Graves' disease (GD) and 336 Hashimoto's thyroiditis (HT) individuals and 851 healthy cohorts. Ligase detection reaction (LDR) and direct sequencing method were used for genotyping the IL-22 gene polymorphisms at rs2046068, rs2227478, rs2227485, rs11611206, and rs1179251. In comparison to female controls, genotype CC of rs1179251 was increased in the female AITD patients. Alleles C at rs2046068, C at rs2227478, and C at rs1179251 linked to the susceptibility of HT males. Genotype CC in rs1179251 was higher in male HT. Variants at rs2046068, rs2227478, and rs1179251 were associated with the AITD teenagers. Besides, genotype GG in rs11611206 was correlated with thyroid-associated ophthalmopathy (TAO). Moreover, allele G at rs11611206 was associated with decreased risk for TAO by 28.9%. Similarly, genotype CC of rs1179251 and genotype GG of rs11611206 were associated with Graves' ophthalmopathy (GO). Allele G in rs11611206 increased people with HT towards the predisposition of hypothyroidism. In conclusion, genetic variants of IL-22 are associated with the occurrence of AITD.

Genetic analysis of innate immunity in Behcet's disease identifies an association with IL-37 and IL-18RAP

Interleukin-1 (IL-1) and the IL-1 receptor (IL-1R) family play an important role in the pathogenesis of inflammatory diseases. This study aimed to investigate the association between single nucleotide polymorphisms (SNP) of IL-1 and IL-1R family genes with Vogt-Koyanagi-Harada (VKH) and Behcet’s disease (BD) in Han Chinese. The case-control study was divided into two stages and included 419 VKH cases, 1063 BD cases and 1872 healthy controls. The MassARRAY platform (Sequenom), iPLEX Gold Assay and TaqMan SNP assays were used to score genotypes of 24 SNPs. The expression of IL-37 and IL-18Rap was measured by ELISA and real-time PCR in genotyped healthy individuals. A significantly lower frequency of the AG genotype, and a higher frequency of the GG genotype and G allele of IL-37/rs3811047 were observed in BD as compared to controls. AA genotype and A allele frequency of IL-18RAP/rs2058660 was significantly decreased in BD as compared to controls. Functional studies performed in healthy controls showed that rs3811047 AG genotype carriers had a higher IL-37 gene expression in peripheral blood mononuclear cells (PBMCs) than GG carriers. GG carriers showed a higher cytokine expression as compared to AG carriers. No association was detected between the tested SNPs and VKH.