Comparison of the nitric oxide levels of the patients with psoriasis vulgaris before and after therapy with methotrexate

53 SUMMARY Psoriasis is a chronic, recurrent, inflammatory and hyperproliferative diseases. Mostly immunological mechanisms are blamed for the etiopathogenesis of the disease. Nitric oxide (NO) has effects on the immunity and inflammation of the tissues. There are many reports in the last few years regarding increases in the levels of NO in the inflammatory dermatoses. The NO levels of the samples of the psoriatic patients have been reported to be increased. However, no sufficient data regarding the serum NO levels is available. In this study, we investigated the role of NO in etiopathogenesis of psoriasis and its relation with the PASI and methotrexate(MTX). With this- aim 22 patients with psoriasis were scored with PASI and the levels of scrum nitrite-nitrate were evaluated before and after therapy with methotrexate. The results were compared with 21 healthy volunteers. We also evaluated the relation of the results with the clinical severity and the cumulative MTX dose. The serum levels of nitrite-nkrate of the psoriatic patients with active lesions were found to be significantly higher than the levels of the healthy volunteers and the patients after therapy. Nitrite-nitrate serum levels of the patients who had received methotrexate therapy and had no lesions were still higher than the levels of the volunteers; A weak relationship was found between the PASI scores and the serum nitrite-nitrate levels before therapy, while there was a very weak reverse relation between the nitrite-nitrate levels and the cumulative MTX dose. The elevated nitrite-nitrate serum levels in the inflammatory period, which decreased after therapy, may suggest the possible role of this mediator in the etiopathogenesis of psoriasis and the potential future use of NO inhibitors in the treatment of psoriasis.