Terminal deoxynucleotidyl transferase activity in neoplastic and nonneoplastic hematopoietic cells.

Terminal deoxynucleotidyl transferase activity was investigated by enzyme assay and (or) an indirect immunofluorescence method with specimens from 151 patients who had a variety of neoplastic and nonneoplastic conditions: leukemia, 62; non-Hodgkin's lymphoma, 36; Hodgkin's disease, seven; lymph nodes without neoplasms, 21; normal peripheral blood, 15; normal bone marrow, ten. Immunologic studies were done on samples from 82 of these patients. Increased terminal deoxynucleotidyl transferase activity was found by both methods in patients who had acute lymphoblastic leukemia and the lymphoid blast crisis of chronic myelocytic leukemia and by the immunofluorescence method in patients who had lymphoblastic lymphoma. A single patient with acute monoblastic leukemia was found by both technics to have increased enzyme activity. Three B-cell proliferations were positive by the enzyme assay; none was positive with the immunofluorescence method. In the remaining 42 B-cell proliferations, the levels of terminal deoxynucleotidyl transferase activity were found to be normal by both the enzyme assay and the immunofluorescence method. Cytoplasmic positivity was observed in as much as 10% of the cells in 13 specimens that were otherwise negative and in eight samples in association with nuclear positivity. A comparison of terminal deoxynucleotidyl transferase activity in microunits/mg protein (enzyme assay) with the percentage of positive cells (immunofluorescence method) yielded a correlation coefficient of 0.62 (P less than 0.01).