Adult T-cell leukemia (ATL) is one of the most difficult diseases to treat because of severe underlying immune deficiency and metabolic disturbance. Interferon has potent antiviral, antiproliferative, and immunomodulating properties, and therefore, this may be a good agent to treat such immune deficient patients with peripheral T-cell leukemia. During a period from April 1984 to August 1985, six patients were treated with interferon-@ (IFN-@), and interferon-? (IFN-7) was given to five patients. Three patients achieved partial remission by IFN-8 administration with a response duration of 1, 1.5, and 12 months respectively, whereas one complete remission and two partial responses were experienced by IFN-7 treatment with 4, 4, and 2 months of response. Side effects of IFN-8 were similar to those of IFN-7 including fever, chills, fatigue, mild hematologic depression, and transient hepatic enzyme abnormalities. These promising results warrant further welldesigned clinical trials including combination with other agents or modalities of treatment. Cancer 59:1059-1062, 1987. DULT T-CELL LEUKEMIA (ATL) presents a distinct A clinicopathologic picture characterized by skin lesions, small peripheral adenopathy, hepatosplenomegaly, hypercalcemia, and a wide range of clinical course.' Also, ATL is an endemic disease in the southwestern district of Japan, and closely associated with the first retrovirus isolated from ATL cells, human T-cell leukemia virus I (HTLV-I).2 Infiltration of the leukemic cells into the vital organs itself causes clinical problems, but patients with ATL are susceptible to and often die of opportunistic infections secondary to the underlying immune deficiency.
Since conventional treatments such as combination chemotherapy and radiation therapy are immunosuppressive, treating these patients is very difEcult. Other forms of therapy or new antineoplastic agents are required to control this disease.
Interferon is one of the significant biological response modifiers with antitumor activity against a variety of tumors including Acquired Immune Deficiency Syndromerelated Kaposi's ~arcoma,~ malignant lymph0ma,4'~ and leukemias6-*