Adult T-cell leukemia observed at Niigata University Hospital.

Eight patients with adult T-cell leukemia (ATL) were observed at Niigata University Hospital during the last seven years. They had typical hematological findings of ATL. All patients tested possessed both natural antibody against ATL-associated antigens (ATLA) in the serum and ATLA in peripheral mononuclear cells. These findings agree with the results of virological analysis in patients with ATL in other areas of Japan and human T-cell leukemia (HTL) in the U.S.A. Six out of the eight patients were native residents of Sado Island in Niigata Prefecture. They showed somewhat different clinical features from patients in other endemic areas and a variety of skin lesions. It was noticeable that the skin lesion regressed spontaneously in two patients. In view of the fact that the total population of this island is about 80,000, the incidence of ATL is thought to be high. Immunological studies were performed in our patients and the immunological background of ATL is discussed.