Background: Psoriasis is a chronic infl ammatory skin disease characterized by pathological skin lesions due to various exogenous and endogenous factors and associated with a number of biochemical and immunological
disturbances. Antioxidant enzymes may be involved in the pathogenesis of the disease. The aim of this study was to evaluate the concentration of lipid peroxidation products and glutathione peroxidase (GPx) activity in the blood of patients with psoriasis before and after treatment by conventional methods.
Material/Methods: The patient group consisted of 67 persons with psoriasis vulgaris who were treated at the Department and Clinic of Dermatology. The duration of the disease was from 3 to 34 years. All patients were
treated topically. The concentration of thiobarbituric acid reactive substances (TBARS) was determined in the blood plasma. The activity of GPx was determined in erythrocytes.
Results: In the healthy persons, GPx activity was 16.8±3.7 U/g Hb and TBARS concentration 0.63±0.16 nmol MDA/ml of plasma. In the psoriasis patients, GPx activity in erythrocytes was 14.8±4.3 U/g Hb and TBARS concentration was 0.73±0.22 nmol MDA/ml of plasma before treatment. The applied external
treatment caused improvement in the clinical state and a slow increase in GPx activity as well as a decrease in TBARS concentration to values comparable to those of the healthy volunteers.
Conclusions: The results suggest that disorders in antioxidant defense mechanisms may play an important role in the pathogenesis of psoriasis.

Keywords: Antioxidants - metabolism, Erythrocytes - enzymology, Glutathione Peroxidase - blood, Oxidants - metabolism, Psoriasis - metabolism, Thiobarbituric Acid Reactive Substances - analysis