 Comparison: Psoriatic patients are treated with intravenous alefacept once per week for 12 weeks. One randomized chosen body-half left or right side is additionally treated with narrowband UVB UVB-311nm three times per week until complete clearance of psoriatic lesions at the UV-treated side. PASI is evaluated before, weekly during, and for 3 to 12 months after alefacept - narrowband UVB treatment. 