Two biopsies were taken from each patient in the first set. The first biopsy was taken from the lesional psoriatic skin and the second from nonlesional skin. All patients were subjected to continuous treatment (in the form of topical steroids and oral systemic methotrexate) and followed up for 2 months. Six patients with moderate to severe degrees of psoriasis and two with palmoplantar subtype of psoriasis (who did not respond to topical steroids) received oral systemic methotrexate. The dosage used was: 15 mg per week in three divided doses taken at 12-hour intervals during a 24-hour period with folate supplementation. Patients receiving systemic methotrexate were subjected to monitoring liver blood tests monthly. Eight patients with mild to moderate degrees of psoriasis were maintained on topical steroid creams and ointments in the form of betamethasone dipropionate, twice daily. At the end of the course of two months, a third psoriatic lesional skin biopsy was taken from all patients.