Treatment of psoriasis vulgaris with a synthetic metalloporphyrin and UVA light.

Sn-protoporphyrin is a synthetic heme analogue which inhibits the catabolism of natural heme to bilirubin and can suppress a wide variety of experimentally induced or naturally occurring forms of jaundice in animals and man. Ten patients, 9 of whom were substantially or completely unresponsive to other forms of therapy, received 2.0 mumol/kg body weight of Sn-protoporphyrin on day 0 of this study followed by UVA light treatment for 21 days. Severity of psoriatic plaques, clinically scored (erythema 0-3; scaling, 0-3; infiltration, 0-3;) declined from a mean +/- score of 7 +/- 0.3 on day 0 to 3.6 +/- 0.7 on day 21. Psoriatic lesions were improved in all patients and in some the effect was dramatic. No deleterious side effects were registered. As shown in this study, one-day treatment with Sn-protoporphyrin followed by conventional UVA light treatment may be a useful therapeutic modality for psoriasis patients and merits further investigation.