Figure 2.

Melanocytes from two individuals with vitiligo are more sensitive to 4-TBP-induced oxidative stress than normal melanocytes. Melanocytes were derived from either vitiligo patients or normally pigmented control individuals, matched for age, sex, and skin type. PIG cells were immortalized by infection with the HPV16 E6/E7 genes.26 Cells were treated with 500 μmol/L 4-TBP in the absence or presence of 500 units/ml catalase for 72 hours, after which viability was determined. Control cells (C) were treated with vehicle alone. Bars indicate SD of triplicates within the experiment. Melanocytes from the individuals with vitiligo were significantly more sensitive to 4-TBP (* indicates P < 0.01), except in the presence of catalase. The experiment was repeated three times; a representative experiment is shown.