Treatment of psoriasis vulgaris with topical calcipotriol: is the clinical improvement of lesional skin related to a down-regulation of some cell adhesion molecules?

Calcipotriol is demonstrably efficacious for the treatment of psoriasis by virtue of its effects on the skin's immune system and on epidermal growth. We performed this study to emphasize the difference in the expression of certain cell adhesion molecules (CAMs) (ICAM-1, ELAM-1, LFA-1, VLA-3, VLA-6) in lesional and perilesional skin of 10 patients with psoriasis, before and after treatment with topical Calcipotriol. We took two biopsies of lesional and perilesional skin from each patient before and after treatment and then performed an immunohistochemical study to observe the expression of these CAMs, utilizing monoclonal antibodies against these adhesion molecules. We noticed reduced levels of infiltrating cells along with the expression of ICAM-1, LFA-1, ELAM-1 and of CAMs VLA-3, VLA-6 in basal and suprabasal keratinocytes. On the basis of these data we hypothesize that, besides epidermal keratinocytes, another target for Calcipotriol may be the skin's own immune system, suggesting that Calcipotriol can modify T lymphocyte activity (IL-1 dependent) through a down-regulation of CAMs.