The interleukin-8 receptor: a potential target for antipsoriatic therapy?

Interleukin-8 is assumed to play a central role in the pathogenesis of psoriasis. Since an increased expression of the interleukin-8 receptor has been observed both in polymorphonuclear leukocytes and in affected psoriatic epidermis, we were interested in whether the interleukin-8 receptor could be a molecular target of antipsoriatic compounds. Cyclosporine, calcitriol, calcipotriol or dithranol caused a dose-dependent decrease in interleukin-8 binding to cultured human keratinocytes, while interleukin-8 binding to granulocytes was not affected. In addition, the interleukin-8-induced human leukocyte antigen-DR (HLA-DR) expression of keratinocytes was nearly completely blocked by treatment of the cells with these substances. The inhibition of the keratinocyte interleukin-8 receptor and its function by antipsoriatic drugs may contribute to their therapeutic action.