The expertise in the characterization of transcriptomics profile in lesional psoriatic skin and on the availability of innovative therapy for these patients.The investigators propose to follow the modification of the skin transcriptomics profile in psoriatic patients during successful Adalimumab biotherapy. Skin transcriptomics profiles of normal skin, psoriatic non lesional skin, and psoriatic lesional skin before and after biotherapy will be compared. The investigators will focus on the modification of the cytokine "signature" in these skin lesions and of some markers of keratinocyte inflammation. The modification of the transcriptomics profile induced by the biotherapy will be correlated to the clinical response Psoriasis Area and Severity Index.