Hypothesis: The balance between type I IFN and TNF determines the response to anti-TNF treatment. The goal of the proposed study is to address this hypothesis and demonstrate that the strength of the type I IFN signature in psoriatic skin is the major determinant of the clinical response to anti-TNF treatment.~Purpose: Determine the strength of the type I interferon and TNF signal in psoriatic skin prior to and during treatment with etanercept and correlate with degree of clinical improvement.~Study Population: up to 50 subjects, men or women over the age of 18 with clinically stable plaque psoriasis, who meet the wash out requirements and other exclusion criteria~Psoriatic patients will receive 100 mg etanercept per week (2 separate single-use pre-filled 50 mg subcutaneous injections taken on two separate days) for 3 months.~Procedures: Urine pregnancy test, TB test, photography, Physical Examinations, Skin Examinations, Study Drug, Peripheral blood and biopsies~Anticipated Results: We expect that patients with strong IFN-α signature in psoriatic skin along with weak TNF-α signature will have minimal response to anti-TNF treatment, while patients with the opposite pattern, weak IFN and strong TNF signature, will have significant clinical improvement.
The purpose of this study is to determine the relationship between two types of cell signals, type I interferon (IFN) and tumor necrosis factor (TNF), in psoriatic skin prior to and during treatment with etanercept and correlate that information with the degree of the improvement in the psoriasis.