Evaluation of Lymphocytic Infiltrate, Dendritic Cells and Cytokines Expression in Psoriatic Lesion and Normal Skin Before and After TNF Alfa Inhibitors Therapy

Inclusion Criteria: * Male and female subjects \> 18 years of age, affected by moderate to severe psoriasis * Subject has had clinical diagnosis of psoriasis for at least 12 months, stable plaque psoriasis for at least 2 months before screening (subjects with concurrent psoriatic arthritis may be enrolled). * Subject is naıve to TNF-antagonist therapy and efalizumab. * Subjects are considered eligible according to the following tuberculosis screening criteria: 1. Have no history of latent or active TB prior to screening; 2. Have no signs or symptoms suggestive of active TB upon medical history and/or physical examination; 3. Within 1 month prior to the first administration of study medication, have negative diagnostic tuberculin skin test. * Normal chest X-ray within 3 months prior to screening with no evidence of malignancy, infection, current or old TB. * Subjects' screening and baseline clinical data must be within the normal limit, including the results of medical history, physical examination and laboratory evaluation (complete blood count, serum values for liver enzymes, bilirubin, glucose, albumin, creatinine and urine analysis). * Willing and able to comply with the protocol requirements for the duration of the study. * Women of childbearing potential must be using adequate birth control measure throughout the study and for 150 days (5 months) after study completion. Exclusion Criteria: * Pregnant or breast-feeding women, or women who are planning pregnancy. * Patients not suitable for TNF alfa inhibitors therapy