ABSTRACT
Interleukin (IL)-IO is an important immunoregulatory cytokine. One of its main biological function seems to be the limitation and termination of inflammatory responses. Remarkably, a relative deficiency in IL-10 expression is found in psoriasis, a frequent inflammatory skin disease, characterized by a type 1 cytokine pattern. Induction of IL-10 expression was found by conventional antipsoriatic therapies, suggesting that IL-10 may be a key cytokine in psoriasis and that application of this cytokine may have therapeutic effects. In first clinical trials over 3-7 weeks in patients with established psoriasis IL-10 was well tolerated and clinical efficient. In a long term trial in patients with psoriasis in remission, IL-10 therapy decreased the incidence of relapse and prolonged the disease free interval. Laboratory investigations suggest that IL-10 exerts its antipsoriatic activity by effects on different cell populations including antigen pre senting cells and T-cells. IL-10 led to a lasting type 1 / type 2 cytokine balance shift. Direct effects of IL-10 on keratinocytes, however, are unlikely to have contributed to the clinical response, since IL-10 unresponsiveness of keratinocytes was found in vitro. IL-10 seems to have major importance in psoriasis. Further investigations are necessary to determine whether its application may represent a promising new therapeutic approach.
