Leukotactic properties of soluble substances in psoriasis scale

In an attempt to elucidate the mechanisms underlying the production of transepidermal migration of leukocytes toward the stratum corneum in psoriatic lesions, the chemotactic properties of soluble substances in psoriasis scales were examined by a modified Boyden's chamber. All crude extracts of horny tissues studied, i.e. callus, scales of exfoliative dermatitis and of psoriasis vulgaris, showed chemotactic activity for human peripheral blood leukocytes. But only the chemotactic activity of the psoriasis scale extract was highly potent. This was greatly reduced after dialysis. Fresh serum was not required to manifest the chemotactic activity. By Sephadex G-200 chromatography, the scale extracts from psoriasis vulgaris and pustular psoriasis had potent activity eluted near the cytochrome C marker. The same fractions of other horny tissue extracts, bacterial filtrate prepared from cultured psoriasis scale fragments, and serum did not show such potent activity. On the basis of analysis by gel filtration and recent findings of immunopathological studies, a postulate was made that a complement derived chemotactic factor, possibly a C5 cleavage product, developed as a result of antigen-antibody reaction in the stratum corneum of psoriatic lesions.