The Release of Leukotriene B4-like Material in Biologically Active Amounts from the Lesional Skin of patients with Psoriasis

The 5,12-dihydroxy metabolite of arachidonic acid, leukotriene B 4 , is a highly potent neutrophil chemoattractant. In view of the characteristic epidermal neutrophil infiltrate in psoriasis, the presence of leukotriene B 4 in samples from untreated lesional and uninvolved skin has been sought. Chambers were fixed to abraded skin and filled with phosphate-buffered saline (PBS). After 35 mm, the fluid was removed, and acidic lipids were extracted and subjected to high-performance liquid chromatography (HPLC). Extracts were purified by both straight- and reversed-phase HPLC, and assay of evaporated fractions by an agarose microdroplet chemokinesis technique indicated the presence of leukotriene B 4 -like material. No significant leukotriene B 4 - like activity was found in samples from uninvolved skin. Subsequent experiments using a modification of the initial skin chamber method indicated that leukotriene B 4 was being released from deeper layers of lesional skin and not only from superficial scale. Monohydroxy-ei- cosatetraenoic acid-like activity was also seen in lesional samples as determined by straight-phase HPLC and chemokinesis assay. These findings and the proinflammatory properties of these compounds in human skin suggest that they may play a role in the pathogenesis of the psoriatic neutrophil infiltrate.