THE EFFECT OF TACALCITOL (1,24(OH)(2)D-3) ON CUTANEOUS INFLAMMATION, EPIDERMAL PROLIFERATION AND KERATINIZATION IN PSORIASIS - A PLACEBO-CONTROLLED, DOUBLE-BLIND-STUDY

The aim of the present study was to discover to what extent 1,24(OH)(2 )D-3 ointment (tacalcitol; 4 mu g/g) can modulate epidermal proliferat ion and keratinization, and several aspects of inflammation. Ten patie nts with psoriasis vulgaris were included in a placebo-controlled, dou ble-blind study, using 1,24(OH)(2)D-3 ointment (4 mu g/g). Before, and after 8 weeks of treatment, punch biopsies were taken from lesions tr eated with the active agent and placebo-treated lesions. An immunohist ochemical study was carried out using monoclonal antibodies against th e hyperproliferation-associated keratin 16, against cycling nuclei, fi laggrin, involucrin, T lymphocytes, Langerhans cells, CD14 and polymor phonuclear leucocytes (PMN). The Wilcoxon test for matched pairs was u sed for statistical analysis of results. The biopsies from the lesions treated with the active agent showed a statistically significant chan ge towards normalization of air aspects of inflammation studied, and o f epidermal proliferation and keratinization, but there did not appear to be any effect on Langerhans cells. The only parameter which showed a significant alteration in the placebo-treated lesions was the numbe r of cycling nuclei in the epidermis (P less than or equal to 002). Ho wever, the biopsies from the plaques treated with the active agent sho wed a greater decrease of cycling cells (decrease: M(active) = 70,M(pl acebo) = 53) and a lower P-value (less than or equal to 0.01). We ther efore conclude that at the cell biological level 1,24(OH)(2)D-3 ointme nt (4 mu g/g) has a substantial effect on several cell types, with reg ard to inflammation, epidermal proliferation and keratinization, with the exception of Langerhans cells.