Estimation of paraoxonase-1 and superoxide dismutase in vitiligo patients before and after photochemotherapy

Background Several findings show that oxidative stress may be an important phenomenon in the pathophysiology of vitiligo. Imbalances in the oxidant–antioxidant system have recently been demonstrated in vitiligo patients. Objective To evaluate the role of oxidative stress in vitiligo by measuring the levels of the antioxidant enzymes superoxide dismutase (SOD) and paraoxonase (PON)-1 in the lesional skin of patients with vitiligo and in the skin of normal controls, and to study the effect of psoralen–ultraviolet rays type A (PUVA) therapy on the levels of these antioxidant enzymes. Patients and methods Fifteen patients with generalized vitiligo and 10 healthy volunteers were included in the study. Four-millimeter punch-skin biopsies were taken from unexposed vitiligo lesions before and after 30 PUVA sessions; a single skin biopsy was also taken from the unexposed skin of each control. Levels of SOD and PON-1 were quantified spectrophotometrically. Results SOD levels were statistically significantly elevated in the patients compared with the controls. After PUVA, the levels decreased significantly but were still higher than those of the controls. However, PON-1 levels were statistically significantly lower in the patients than in the controls. Following phototherapy sessions, the levels were significantly increased, but were still significantly lower than those of the controls. Conclusion Our findings demonstrated that there is an impairment in the antioxidant system in vitiligo, leading to free radical-mediated damage to melanocytes. In view of these findings, antioxidants may play an adjuvant role in the management of vitiligo in addition to specific therapies.