[Mutagenic activity of urine of patients with psoriasis treated with pharmaceutical black coal tar]

Examination of patients exposed for prolonged periods to black coal tar used in dermatology for the treatment of psoriasis revealed its carcinogenic effect. The objective of the present work was to assess the mutagenicity of urine samples from psoriatic patients treated with pharmaceutical black coal tar before treatment, and 14 and 28 days after application of the preparation.

To a group of 19 patients with psoriasis vulgaris (12 men, mean age 43.3 +/- 3.96 years and 7 women, mean age 44.7 +/- 4.02 years) daily black coal tar in the form of Sack's tincture for a period of 28 days was applied to 10 - 80% of the body surface, i.e. 1000 - 13,000 cm2 of skin, amounting to 10 - 40 g. The mutagenic activity of urinary extracts was assessed by means of the Ames test on bacterial strain TA 98. It was revealed that urine samples from all patients exposed during the therapeutic procedure has a greater mutagenic activity, as compared with controls, whereby the mutagenicity index was higher in smokers (2.1) than in non-smoker patients (1.88) in the presence of the metabolic activating system. The elevated values of the mutagenicity index were recorder after the 14th day (2.25) and after the 28th day of treatment (2.07), as compared with controls (0.93); p < 0.05. Before the onset of treatment the mutagenicity index was 1.64.

The assembled results confirm the view of an increased genotoxic risk in psoriatic patients treated with preparations containing black coal tar.