Serum TNF-α in psoriasis after treatment with propylthiouracil, an antithyroid thioureylene

BACKGROUND Tumor necrosis factor-alpha (TNF-alpha) and its receptors play important roles in the development and persistence of psoriatic plaques. The antithyroid thioureylenes, propylthiouracil and methimazole, are effective in the treatment of patients with psoriasis with a significant number of patients showing clearing or near clearing of their lesions after a several weeks of treatment. METHODS The present study examined the effect of treatment with propylthiouracil, given in a dose of 100 mg every 8 hours for 3 months, on the serum levels of TNF-alpha in 9 patients with plaque psoriasis. RESULTS Propylthiouracil therapy did not result in a significant decline in serum TNF-alpha concentrations. CONCLUSIONS The findings suggest that the therapeutic effect of propylthiouracil in psoriasis appears not to be related to any change in the concentration of TNF-alpha but occurs via an anti-proliferative mechanism as we have previously speculated.