Combined effect of cytokine gene polymorphisms on end-stage knee osteoarthritis from Chinese Han population

Association of rs1800795 and rs1800796 polymorphisms in interleukin-6 gene and osteoarthritis risk: evidence from a meta-analysis

Multiple studies have investigated the association of interleukin-6 (IL-6) gene polymorphisms and osteoarthritis (OA) risk, but failed to reach a consistent conclusion. Therefore, this study was designed to elucidate the association of IL-6 polymorphisms and OA by a meta-analysis approach. Literature retrieval was carried out on PubMed, EMBASE, Web of Science, CNKI, and Wanfang databases. The strength of association was appraised by odds ratios (ORs) and 95% confidence intervals (95%CIs) in five genetic models. The data were merged by using RevMan 5.3 software. Ten studies with 4944 cases and 4651 controls were analyzed. Overall, no significant association was identified between rs1800795 polymorphism and OA. Subgroup analysis by ethnicity and OA site also suggested rs1800795 polymorphism was not associated with OA. For rs1800796 polymorphism, G-allele and GG-genotype carriers appeared to have an increased risk to OA (G vs. C, OR = 1.66, 95%CI 1.30-1.96, P < 0.01; GG vs. CC, OR = 1.75, 95%CI 1.07-2.84, P = 0.03; GG vs. GC + CC, OR = 1.82, 95%CI 1.42-2.34, P < 0.01). Findings of this study indicate that the rs1800795 polymorphism is not correlated to OA susceptibility, regardless of ethnicity or OA site. However, rs1800796 polymorphism trends to be associated with susceptibility to OA.

The IL-6 rs12700386 polymorphism is associated with an increased risk of developing osteoarthritis in the knee in the Chinese Han population: a case-control study

Background

This case-control study aims to examine the association between the Interleukin-6 (IL-6) rs12700386 polymorphism and the increased risk of developing osteoarthritis (OA) in the knee in the Chinese Han population.

Methods

We extracted DNA from 763 subjects (352 OA patients and 411 healthy controls). The relative expression levels of IL-6 in blood samples of patients with knee OA was determined by quantitative reverse transcription PCR (qRT-PCR) and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used for genotyping the IL-6 gene polymorphism.

Results

We found that the IL-6 polymorphism rs12700386 enhanced patient susceptibility to developing knee OA. Based on a subgroup analysis, the risk of developing knee OA was elevated in smokers, drinkers, and subjects ≥55 years old or with BMI ≥ 25 kg/m². The combination of smoking, drinking, and having the rs12700386 genotype led to an increase in the risk of developing knee OA, indicating that an underlying interaction between gene and environment exists. The rs12700386 genotype was found to be correlated with an increase in IL-6 expression. We also found that IL-6 levels were significantly higher in the CC genotype compared to the GG genotype carriers in OA patients.

Conclusion

These data suggest that the rs12700386 polymorphism in the IL-6 gene leads to an increase in the risk of knee OA in Chinese Han individuals.

Association of cytokine gene polymorphisms with osteoarthritis susceptibility

Osteoarthritis (OA) is a multifactorial disease characterized by low-grade inflammatory processes that are mediated initially by the cells and factors of the innate immune system. In addition to their key role in inflammation, cytokines contribute to the pathogenesis of OA through angiogenesis and chemotaxis. The purpose of the present case-control study was to investigate a possible association of four cytokine single nucleotide polymorphisms (SNPs), IL-4R -3223C>T (rs2057768), IL-8 -251T>A (rs4073), IL-10 -1082A>G (rs1800896) and TNF -A-308G>A (rs1800629) with OA susceptibility. Genomic DNA was isolated from blood samples collected from 305 Romanian subjects (90 patients with OA and 215 controls) and the genotyping of the SNPs was performed by TaqMan allelic discrimination polymerase chain reaction using predesigned assays. Our data indicated a significant association for IL-4R rs2057768 C>T SNP. The subjects that carried the CT genotype were at a higher risk for OA (OR 2.03, 95% CI: 1.21-3.42, P=0.007) compared with those that had the CC genotype. Furthermore, the carriers of the T allele were at a 1.9 fold higher risk for OA (OR 1.92; 95% CI, 1.17-3.17; P=0.009) in a dominant model. The association remained significant only for knee OA in the subgroups analysis. No correlations were observed between the other remaining SNPs and OA. The results suggested that the IL-4R rs2057768 SNP could contribute to OA susceptibility in the Romanian population, providing novel evidence for the involvement of IL-4/IL-4R pair in the pathogenesis of OA.

Relationships of common polymorphisms in IL-6, IL-1A, and IL-1B genes with susceptibility to osteoarthritis: a meta-analysis

Observational and experimental studies have arrived at inconsistent conclusions about whether common polymorphisms in IL-6, IL-1A, and IL-1B genes are associated with an increased risk of osteoarthritis (OA). Therefore, we undertook a comprehensive meta-analysis to more systematically summarize the relationships of IL-6, IL-1A, and IL-1B genetic polymorphisms with susceptibility to OA. We screened the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM), and China National Knowledge Infrastructure (CNKI) databases up to 31 March 2014. We used STATA software to analyze statistical data. Odds ratios (ORs) and their corresponding 95 % confidence intervals (95 % CIs) were calculated. Seventeen independent case-control studies were included in this meta-analysis with a total number of 7,491 subjects, comprised of 3,293 OA patients and 4,729 healthy controls. Our results indicate that IL-6, IL-1A, and IL-1B genetic polymorphisms are statistically correlated with an increased risk of OA under the allele and dominant models. According to a subgroup analysis based on disease, a higher frequency of IL-6 genetic polymorphisms was observed among knee OA and hand OA patients, but not among hip OA and DIP OA patients. A higher frequency of IL-1A genetic polymorphisms were found among hip OA patients, hand OA, hip OA and DIP OA patients. Furthermore, we observed a higher IL-1B polymorphism frequency among knee OA and hip OA patients, but not among hand OA patients. Our findings provide evidence that IL-6, IL-1A, and IL-1B genetic polymorphisms may be correlated with susceptibility to OA.