Cyclosporine A in the treatment of psoriasis: a clinical and mechanistic perspective.

Cyclosporine A, a unique immunomodulatory agent, has been used increasingly over the last 5 years in the management of severe psoriasis. The remarkable efficacy of this drug coupled with its known immunosuppressive properties have enabled a further appreciation of the role of the immune system in the induction and maintenance of psoriatic plaques. Although acting primarily on T lymphocytes, there is also evidence for an effect of cyclosporine A on other constitutive cell types within the skin. The future use of systemically administered cyclosporine A in the treatment of psoriasis and other cutaneous diseases is dependent on the successful balance of efficacy and side-effect profile; namely, the dose-related problems of hypertension and nephrotoxicity. As a result of the toxicity encountered with systemically administered cyclosporine A, attempts to formulate a successful topical preparation for use in cutaneous disease are being made. The advent of cyclosporine A provides the dermatologist with a new therapeutic strategem in the management of psoriasis, although the long-term safety of such interventional therapy remains to be discerned.