PTU also has antioxidant potential along with antiproliferative and immunomodulatory effects indicated by its role in increased lipid peroxidation and decreased antioxidant activity (SOD) in psoriasis [35]. Malondialdehyde (MDA), the end product of lipid peroxidation, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and antioxidant enzymes were measured in plasma, erythrocytes, and skin biopsies of psoriatic patients before and after eight weeks of oral treatment with PTU (300 mg/day) or PTU/thyroxine (25 mg). The gene discussed is SOD1; the disease is psoriasis.