DNA nucleotidylexotransferase of normal persons and leukemic patients.

We describe a relatively simple and rapid assay for DNA nucleotidylexotransferase (EC 2.7.7.31) activity in normal lymphocytes and leukemic cells from blood and (or) bone marrow of patients with various types of leukemia. We followed the method of Beutler and Kuhl (Am. J. Clin. Pathol. 70: 733, 1978) but separated the product of the reaction by precipitation on filter-paper disks instead of by centrifugation. Normal lymphocytes had a mean activity of 13.5 (SD = 9.21; range 3 to 35) pU/10(8) cells. Leukemic cells from the peripheral blood of patients with acute myelogenous leukemia had a mean activity slightly greater than normal (48 pU/10(8) cells); those from patients with acute lymphoblastic leukemia had a mean activity of 863 pU/10(8) cells, or 62-fold the normal mean. Similarly, cells from patients with chronic myelogenous leukemia in acute phase had a normal activity when the cell proliferation was myelogenous, but much higher activities when the cell proliferation was lymphoblastic. Cells from patients with chronic lymphocytic leukemia had normal activity. In leukemic patients, approximately similar results were obtained with cells isolated from bone marrow.