Safety and Tolerability of Repeat Courses of IM Alefacept

Inclusion Criteria: 1. Must give written informed consent. 2. Must require systemic therapy or phototherapy for their psoriasis, as determined by the investigator prior to Visit 1. Exclusion Criteria: 1. Female subjects who are not postmenopausal for at least 1 year, surgically sterile, or willing to practice effective contraception during the study. Nursing mothers, pregnant women and women planning to become pregnant while on study are to be excluded. 2. Current enrollment in any investigational study in which the subject is receiving any type of drug, biologic, or non-drug therapy (participation in registry-type studies is allowed). 3. Serious local infection (e.g., abscess) or systemic infection (e.g., pneumonia, septicemia) within the 3 months prior to the first dose of investigational drug. 4. Any subject whose CD4+ lymphocyte count at study entry is less than 404 cells/mm3. 5. Treatment with another investigational drug or approved therapy for investigational use within 28 days prior to investigational drug administration. 6. Treatment with systemic retinoids, systemic steroids, methotrexate, cyclosporine, azathioprine, thioguanine or other systemic immunosuppressant agents within the 28 days prior to investigational drug administration. 7. Phototherapy, including Ultraviolet B (UVB) and Psoralen + Ultraviolet A (PUVA), within 28 days prior to investigational drug administration. 8. Known HIV+, known viral Hepatitis infection, known tuberculosis infection.