[Significance of terminal deoxynucleotidyl transferase in patients with acute leukemia and malignant lymphoma: results obtained by immunofluorescence assay (author's transl)].

Deoxynucleotidyl transferase (TdT) is of diagnostic and therapeutic importance in acute leukaemia and malignant lymphoma. Previous methods for determining TdT activity by biochemical assay are complex and require the use of radioactive substances. There now is available a specific antibody for immunofluorescent demonstration of TdT. The two methods were compared on samples from 43 patients with leukemia or malignant lymphoma. There was very good agreement. High TdT activity was found in 12 of 14 patients with acute lymphatic leukemia and in one of two with acute undifferentiated leukaemia. TdT activity was absent with acute and chronic myeloid leukaemia, chronic lymphatic leukaemia and non-Hodgkin's lymphoma of low malignancy. Immunofluorescence assay, although its results are of similar significance to that obtained with the biochemical tests, is simpler to do. Furthermore, it can be done on normal bone-marrow smear or lymph-node preparations and can be correlated with the morphological findings.