Topical calcipotriol for psoriasis--an immunohistologic study.

The aim of the present study was to investigate the distribution of Langerhans cells and T cells in the lesions and also the phenotypic expression of markers of activation on lesional T cells and keratinocytes, before and after 2 weeks of topical treatment of 7 psoriatic patients with calcipotriol. Before treatment, the infiltrate was composed mainly of T cells and there was decreased expression of CD1 on the intra-epidermal Langerhans cells. ICAM-1 and EGF receptor were present throughout the epidermis, but keratinocytes expressing Transferrin receptor were detected only in the basal layer. After 14 days of calcipotriol therapy, there were significantly fewer CD4T cells in the dermis and an increased number of intraepidermal CD1 + Langerhans cells. ICAM-1 expression on lesional keratinocytes was reduced in all patients, but the expression of EGF receptor was decreased in 3 patients only, and Transferrin receptor expression on keratinocytes had not changed. All these changes were concurrent with moderate clinical improvement of the lesions. The results suggest that in the early stages of the clinical response to calcipotriol there is an immunomodulating effect of the drug associated with variable decreases in keratinocyte expression of markers of activation.