Patients must be age 18 or older.

Patients male or female must use contraception if of childbearing age. No men and women actively attempting to conceive a child during the time of drug testing. No pregnant or nursing women.

Patients must be otherwise healthy, immunocompetent, ambulatory patients with psoriasis who have more than 5 percent of their body surface area involved with the disease or who have localized disabling psoriasis.

Have failed one prior topical treatment regimen including topical cortiscosteroids, coat tar preparations, or ultraviolet light.

An ambulatory performance status of 0,1,2 (ECOG Scale).

Ability to participate in an out -patient study and to provide informed consent.

Creatinine less than 2.0 mg/100ml. Bilirubin less than or equal to 1.5 mg/100ml; prothrombin time less than or equal to 1.3 times control. WBC greater than 3000/mm(3), granulocytes greater than 1500/mm(3), platelets greater than 100,000/mm(3).

No clinically significant cardiac disease.

No patients with previously documented serious infectious diseases such as pneumocystis pneumonia, mycobacterium avium infection, etc. which would suggest clinically evident immunodeficiency.

No systemic treatment for psoriasis (methotrexate, PUVA, UVB, cyclosporine, etc.) and topical treatments (corticosteroids, tar, anthralin, etc.) during the four weeks prior to study entry, and topical treatment during the two weeks prior to study entry.