Immunomodulatory drugs for psoriasis

摘要

With a prevalence of 2-3%, psoriasis is among the most common skin diseases. Clinical hallmarks comprise erythematous plaques covered by silvery scaling and a chronic recurrent course. Psoriasis is now considered an autoimmune disease in which antigen presentation to cutaneous T helper cells triggers secretion of cytokines, causing proliferation of keratinocytes and expression of adhesion molecules on endothelial cells. These attract additional effector T cells from the circulation, which are then activated in an antigen specific manner, leading to secretion of more cytokines and perpetuation of the process. Although topical treatments are sufficient for many patients, about 20% need additional systemic drugs. All of these bear a considerable potential for serious side effects, such as hepatotoxicity and nephrotoxicity (methotrexate, cyclosporine), teratogenicity (oral retinoids), and cancer (PUVA, which is psoralen and long wave ultraviolet radiation; cyclosporine), which limits their long term use. The limitations of treatments on the one hand and a growing understanding of the pathogenesis of psoriasis on the other have stimulated much interest in the field of immunomodulation for the management of this chronic disease.