Improvement of psoriasis vulgaris after intralesional injections of 15-hydroxyeicosatetraenoic acid (15-HETE).

Psoriatic skin lesions are characterized by elevated levels of 5- and 12-lipoxygenase products (leukotrienes B4, C4, and D4, and 12-hydroxyeicosatetraenoic acid [12-HETE]), which can stimulate epidermal proliferation and induce skin inflammation. 15-Hydroxyeicosatetraenoic acid (15-HETE) has the potential to inhibit the activity of 5- and 12-lipoxygenases. The purpose of the present study was to determine the therapeutic effect of intralesional injections of 15-HETE. 15-HETE was formed by oxidation of arachidonic acid by soybean lipoxygenase, purified by reversed-phase high-performance liquid chromatography, and identified by mass spectrometric analysis. Thirteen patients took part in the investigation. Plaques with a diameter of approximately 1 cm were injected with 0.1 ml of 10 mumol/L 15-HETE, 0.1 ml of 1 mumol/L 15-HETE, or 0.1 ml of saline weekly. After 3 weeks the effect was evaluated clinically and histologically by an observer uniformed of the treatment given. We found that plaques injected with 10 mumol/L 15-HETE had cleared completely in four patients and improved considerably in seven. In one patient minimal improvement only was seen and in one patient no change was observed. Injection of 1 mumol/L 15-HETE was without effect in 11 patients and improvement was observed in two patients. Of the plaques injected with saline, minimal improvement was observed in one patient; otherwise the plaques had not changed. Injection of 0.1 ml of 10 mumol/L 15-HEPE (identical to 15-HETE except for five double bonds instead of four) induced only minimal improvement in one of four patients. The results imply that 15-HETE by a dose-dependent and stereospecific mechanism can improve psoriasis.(ABSTRACT TRUNCATED AT 250 WORDS)