[Update in the pathogenesis of psoriatic arthritis].

Psoriasis and psoriatic arthritis are autoimmune diseases that share common pathogenic mechanisms. The cause and the pathogenesis of these diseases are unknown; however, there is increasing evidence which suggest that cytotoxic CD8T cells, Th1 and Th17 may be involved in the pathogenesis of these diseases. Cytokines produced as the result of Th1 and Th17 responses, such as TNF-α and IL-17, play a key role in the chronic inflammatory response observed in the joints of psoriatic arthritis patients. It is conceivable that unraveling of the pathogenesis of this disease may lead to the development of new therapeutic approaches and may improve the prognosis of patients.