THE CD11B CD18-INTEGRIN IN THE PATHOGENESIS OF PSORIASIS/

The aim of the present investigation was to study the distribution of CD11b, CD18, and ICAM-1 over the various cell populations present in t he margin zone of the actively spreading psoriatic lesion and distant uninvolved psoriatic skin. This study was performed in order to obtain more insight in the relevance of these receptor molecules in the earl y phase of psoriatic plaque development. Skin biopsies were taken and inflammation markers were assessed using immunohistochemical technique s. All dermal changes in the margin zone preceded those in the epiderm is. In the margin zone the most peripheral change was a decrease in de rmal ICAM-1-expression, followed by an increase in dermal CD11b-expres sion. CD11b-positive cells showed a different tissue distribution from polymorphonuclear leukocytes and were more abundantly present, sugges ting significant amounts of CD11b-bearing cell populations other than polymorphonuclear leukocytes in the early phase of psoriasis. Decrease d numbers of CD18-positive cells in distant uninvolved skin suggest th e existence of a selective modulating mechanism altering the trafficki ng of myeloid subpopulations. Polymorphonuclear leukocytes appeared to invade the skin well after the appearance of CD11b- and CD18-positive cells. (C) 1998 Elsevier Science Ireland Ltd.