Serum level of interleukin-17 in patients with psoriasis

Introduction: Psoriasis is one of the most common chronic and disabling dermatoses. Recent studies showed that interleukin-17 (IL-17) may play a role in the development of psoriasis. Objectives: In this study, serum levels of IL-17 in psoriatic patients was compared with healthy controls; besides, in patients with psoriasis, serum levels of IL-17 were compared with pre-treatment levels, after topical treatments. Patients and Methods: In this case-control study, serum levels of IL-17 were measured and compared in 30 psoriatic patients and 30 healthy individuals matched to age, gender and body mass index. After evaluating the severity of psoriasis with PASI (Psoriasis Area Severity Index), they were treated with psoriasis topical corticosteroids for four weeks. IL-17 and PASI levels were re-evaluated after the treatment without any intervention. Results: Before the start of treatment, the mean±SD of serum level of IL-17 was 6.24±4.65 pg/mL and 2.0 ± 0.75 pg/mL in psoriatic patients and control group, respectively (P=0.001). The mean±SD of PASI severity scale of patients was 10.68 ± 6.65 and 6.16±4.2 before and after treatment, respectively (P<0.001). The mean±SD of serum level of IL-17 of patients before and one month after treatment were 6.24±4.65 and 3.34±1.77 pg/mL, respectively. Conclusion: In psoriatic patients, serum levels of IL-17 increased significantly compared to healthy subjects. Treatment of psoriasis with topical corticosteroids for four weeks reduced the serum level of IL-17 and the severity of disease.