Identification of chemotactic lipoxygenase products of arachidonate metabolism in psoriatic skin.

Skin biopsies and scale extracts from 22 patients with psoriasis were examined for the presence of chemotactic lipoxygenase products of arachidonate metabolism. Heat-stable leukocyte chemotactic activity in aqueous extracts of 2-mm punch biopsies from involved and uninvolved patient skin was significantly elevated, compared to healed psoriatic skin and to skin of normal controls. Ether extracts (pH 3.0) from 13 mg of psoriatic scales contained a mean chemotactic activity corresponding to that of leukotriene B4, 5 X 10(-8) M. On reverse phase high-pressure liquid chromatography, the main chemotactic lipids in scale extracts were leukotriene B4 and 5-HETE. Since lipoxygenase products are potent mediators of inflammation, they may play an important role in the evolution and maintenance of psoriatic lesions.