 Psoriasis is an inflammatory skin disease that affects an estimated 2 to 3 of the worlds population. There are a wide range of local and systemic clinical treatments and agents for clearing, or at least reducing the expression of, psoriatic skin lesions. There is a new generation of antipsoriatic drugs that specifically target T-cell mediated inflammatory pathways and that are approved for the treatment of moderate to severe psoriasis in the United States. Alefacept Amevive is one of these so-called biologics. Alefacept appears to have several advantages over other systemic antipsoriatic agents and is very well tolerated by patients. Weekly administration of alefacept for 12 weeks reduced the psoriasis area and severity index PASI by greater than 75 in 30 of patients. The maximal antipsoriatic effect, however, apparently occurs after the 12-week course has ended. In vitro studies and previous case reports suggested that alefacepts antipsoriatic effect may be augmented when it is administered in combination with UVB. These findings prompted us to conduct a prospective randomized half-body comparison study, in which we ask whether the clinical response of psoriatic lesions to alefacept could be improved by combining alefacept with standard UVB 311nm phototherapy. 