Polymorphonuclear leucocyte chemotaxis in response to leukotriene B4 in treated and untreated psoriatics

Various chemoattractants have been implicated in the aetiology of the polymorphonuclear leucocyte (PMN) migration into the epidermis seen in early lesions of psoriasis. Using an under-agarose technique, the in vitro chemotactic responses of PMN to the arachidonic acid lipoxygenase product leukotriene B4 (LTB4) were assayed in five groups of subjects: normal healthy volunteers (n = 12), untreated psoriatics (n = 11) and psoriatics treated with topical tar (n = 12), PUVA (n = 11) and UVB phototherapy (n = 10). No significant difference was observed between the responses of control subjects and of untreated psoriatics, nor between the untreated psoriatic group and the PUVA- and UVB-treated groups, respectively. However, comparison of the tar-treated and untreated groups revealed a significantly increased chemotactic response to LTB4 in the tar-treated group (p less than 0.01).