Influence of interleukin 17 A and 17 F polymorphisms in keratoconus

Background Until a few years ago, keratoconus was defined as a noninflammatory degenerative disease. However, recent studies have shown that the altered balance between inflammatory cytokines, proteases, and protease inhibitors, as well as free radicals and oxidants, have a crucial role in the pathogenesis of this disease. The aim of this study is to investigate whether interleukin 17 A G197A (rs2275913) and interleukin 17 F T7488C (rs763780) polymorphisms are associated with keratoconus in patients from a population of the northwestern region of the State of São Paulo, Brazil. Methods and Results 35 patients and 61 controls were enrolled. Genotyping of interleukin 17 A G197A and interleukin 17 F T7488C polymorphisms was carried out using the polymerase chain reaction-restriction fragment length polymorphism technique. Statistical analyses were conducted using the chi-square test, and an odds ratio with a 95% confidence interval was also calculated to evaluate the association between polymorphisms and disease. Evaluating interleukin 17 F T7488C, we found that the TT genotype is associated as a risk factor for keratoconus ( P = 0.04; OR = 3.01; CI 1.11–8.14). As for evaluating interleukin 17 A G197A, the allele and genotype frequencies between patients and controls were compared and no statistically significant differences were found. Conclusions Our data showed that the interleukin 17 F T7488C polymorphisms may exert an influence in keratoconus.