TNFalpha and its receptors in psoriatic skin, before and after treatment with etanercept

Psoriasis is a chronic inflammatory skin condition characterized by inflammatory dermal infiltrate and hyperproliferative keratinocytes. The pathogenesis of this disease is mediated by a dysregulation of the innate immunity and cytokine production. Tumor necrosis factor alpha (TNFalpha) is considered the most important cytokine involved in the pathological mechanism of psoriasis. Recently, several therapies have been introduced for the treatment of psoriasis that try to block TNF alpha activity. Among these treatments etanercept is a fusion protein that specifically targets TNF alpha. We performed a study on twelve psoriatic patients aimed at evaluating the effect of etanercept treatment on the production and expression of TNFalpha and its receptors, in lesional and uninvolved psoriatic skin. We demonstrated that after three month of etanercept treatment at 50 mg/wk, TNF, TNF-RI and TNF-RII immunostaining in lesional and non-lesional skin samples of patients was greatly reduced, suggesting that this treatment not only acts on stable lesional plaques, but also at a very early stage of the disease.