Association of interleukin-17 single nucleotide polymorphisms with susceptibility to osteoarthritis

Abstract

Objective To test single nucleotide polymorphisms (SNP) of IL-17A G-197A and IL-17F T7488C in the Chinese Han nationality population and analyze the association of the SNP with susceptibility to osteoarthritis. Methods Two hundred patients with primary knee OA underwent total knee arthroplasty and 200 healthy individuals were recruited into this study from January 2008 to December 2015. We obtained DNA from 2 ml of whole blood for 200 OA patients (OA group) and 200 healthy (healthy control group) to employed a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) assay to identify the genotypes IL-17A G-197A (rs2275913) and IL-17F T7488C (rs2275913). The distribution of IL-17A G-197A (rs2275913) and IL-17F T7488C (rs2275913) genotypes and allele frequencies were detected between the two groups. Chi-square test was used to compare genotype and allele frequency of IL-17A G-197A and IL-17F T7488C between the two groups. If the difference between the two groups was statistically significant, then odds ratio (OR) and 95% confidence interval (95%CI) would be calculated. Results The frequency of AA, AG and GG genotype of IL-17A G-197A(rs2275913) was 4.0%, 54.0% and 42.0% in OA group, which differed from control group (18.0%, 53.5% and 28.5%). The frequency of A and G allele were 31.0% and 69.0% in OA group, which differed from control group (44.8% and 55.3%). The risk of OA in carriers with an G allele (G/A or G/G genotypes) was statistically higher compared to that of carriers with the A/A genotype (AG: OR=0.862, 95%CI=0.729-1.019; GG: OR= 1.259, 95% CI=0.967-1.639; A:OR=0.693, 95% CI=0.577-0.831; G:OR=1.249, 95% CI=1.119-1.394). The distributions of TT, TC and CC genotypes for the IL-17F T7488C polymorphism (rs763780) in OA patients and controls shown 76.5%, 18.0%, 5.5% and 81.5%, 15.5%, 3.0%,respectively. The frequency of T and C allele were 85.5%, 14.5% and 89.3%, 10.8% in 2 group. There were no significant differences in the alleles frequency and genotypes distribution for IL-17F T7488C between OA patients and volunteers. Conclusion Polymorphism of IL-17A G-197A may be closely associated with susceptibility to the development of OA in the Chinese Han nationality population. Genotype G/A and G/G of rs2275913 is a high factor for OA while AA is a low risk factor. However, there is no relationship between rs763780 and OA susceptibility. IL-17F T7488C gene does not increase the risk of suffering from OA. Key words: Osteoarthritis, knee; Interleukins; Genetic testing; Disease susceptibility