IL 17 Cytokine in Psoriasis: Before and After Methotrexate and NBUVB Phototherapy: A Longitudinal Study

Background: Psoriasis, a disease of abnormal epidermal proliferation, was found to be T helper-1 disease. Currently a new concept of T Helper 17 has been found to play a major role through
IL-17 and IL-22 cytokines in the disease pathogenesis.
Aim: Since IL 17 is one of the key effector cytokine of Th17 pathway, we conducted a 12 week longitudinal study of effect of NBUVB phototherapy and Methotrexate on serum IL 17 levels in patients with psoriasis before and after treatment.
Materials and Methods: This was a prospective longitudinal study done on 28 psoriasis patients with PASI>10 and 10 controls. Serum IL-17 levels and PASI scoring was estimated at baseline and after 12 weeks after therapy with weekly intramuscular injection of 15mg of methotrexate and biweekly NBUVB phototherapy.
Results: Baseline PASI score was 24.23 ± 7.5 which reduced to 9.66 ± 4.2 (P value<0.0001). The serum IL 17 level at baseline was 2.65 ± 0.7 pg/ml. which reduced to 1.99 ± 0.57 pg/ml, P value<0.0001. Serum Interleukin 17 level of the psoriasis patients at baseline was 2.65 ± 0.7 pg/ml compared to 2.5 ± 0.9pg/ml in the controls. The difference is not statistically significant. There was a positive correlation between the serum levels of IL-17 and severity
of PASI score (𝑟=0.95).
Limitation and Conclusion: The levels of IL 17 in the lesions were not measured in this study. So this is recommended in future studies to correlate with the serum levels. In this era of biological, we were able to establish a beneficial role of Methotrexate and NBUVB phototherapy in reducing the key effector cytokine IL-17 in the serum and thus helping in treatment of psoriasis.