Evaluation of the relationship of IL17A and IL17F gene polymorphisms with the response to treatment in psoriatic patients using biological drugs: case-control study in patients in eastern Turkey

Introduction
IL-17A and IL-17F cytokines have important roles in the pathogenesis of psoriasis.

Aim
To examine the associations of IL-17A rs2275913 and IL-17F rs763780 variants with the development of psoriasis and whether these polymorphisms affect the responsiveness of biological agents.

Material and methods
In our case-controlled study, which included 83 psoriatic patients who were treated with different biological agents and 69 healthy controls, we genotyped IL-17A rs2275913 and IL-17F rs763780 variants using TaqMan probes.

Results
We did not observe statistically significant changes in genotype frequencies of IL-17A rs2275913 (p = 0.922) and IL-17F rs763780 (p = 0.621) variants between patient and control groups. Although we did not find any association between these polymorphisms and the development of psoriasis, statistical analyses showed that individuals with the IL-17A AA genotype had shorter disease duration (9.09 ±6.82, p = 0.020) and AA genotype frequency was higher in patients who used single conventional treatment (34.6%; p = 0.025). Another analysis also showed that 36.4% and 45.5% of patients who had less than 10-year disease duration were detected as IL-17A AA genotype (p = 0.009). For patients with PASI90 and PASI100 response, the IL-17A AA genotype was significantly higher (p = 0.015). On the other hand, we did not detect any statistically significant correlation between variants and response to biological agents.

Conclusions
According to our results, we may suggest that rs2275913 variant seems to be associated with disease duration, use of single conventional treatment and responsiveness of PASI90 and PASI100 however both variants have no effect on the susceptibility to psoriasis in the population of Eastern Turkey.