IL17A (rs2275913 G>A) and IL17F (rs2397084 T>C) Gene Polymorphisms: Relation to Psoriasis Risk and Response to Methotrexate.

Abstract Background The relation of IL17 polymorphisms to psoriasis risk and response to methotrexate has not been previously studied in Egyptians. Objectives To study the relation of IL17A (rs2275913 G>A) and IL17F (rs2397084 T>C) polymorphisms to psoriasis risk and assess their predictive role as regards response to methotrexate.Patients & Methods IL17A (rs 2275913) and IL17F (rs 2397084) polymorphisms were evaluated in 100 healthy subjects and 100 patients with chronic plaque psoriasis by real time-PCR. Patients were given methotrexate weekly intramuscularly (0.6mg/kg) for 12 weeks. Results IL17F TT genotype was more frequent in patients (87%) than controls (68%), while TC genotype was more frequent in controls (32%) than patients (13%). TT genotype was associated with increased risk of psoriasis whereas the TC allele was associated with a decreased risk. There was no significant difference regarding IL17A GG, GA and AA genotype frequencies between patients and controls. PASI ≥75% was achieved in 22 patients (73.3%) with the TT genotype and 8 patients (26.7%) with TC genotype (p=0.019). Conclusion IL17F (rs2397084 T>C) TT genotype could be considered a susceptibility marker in Egyptian patients. Psoriatic patients with TT genotype and T allele of IL17F (rs2397084 T>C) are likely to show a better response to methotrexate.