Abstract
Transepidermal migration of leukocyte with resultant formation of microscopic or macroscopic sterile pustules is a phenomenon characteristically noted in psoriasis and related sterile pustular dermatoses such as pustular psoriasis, pustulosis palmaris et plantaris and subcorneal pustular dermatosis. We found that crude scale extracts of these dermatoses show remarkably high neutrophil chemotactic activity as compared with those of other non-psoriatic inflammatory dermatoses. We isolated psoriatic leukotactic factor (PLF) with a molecular weight around 12KD as a chemotactic peptide distinct from those common to other inflammatory changes involving the skin and from those released by bacteria. Further analysis of PLF identified C5 cleavage fragments together with other anaphylatoxins. Recently chemotactic peptides derived from monocyte are suspected to be also present in PLF. Likewise, potent cell membrane-derived lipid chemotactic factor leukotriene B4 is also increased in these lesions, although its specificity to them is not clear because it is also increased in other inflammatory dermatoses not characterized by transepidermal leukocyte chemotaxis. Moreover, the peripheral blood leukocytes from active psoriatic patients show enhanced function in chemotaxis, phagocytosis, active oxigen production and enzyme release; their sera contain substances such as anaphylatoxins that activate leukocyte function.
