Quantitative enzyme determination; a parameter for leukemic cell differentiation.

In acute myeloid leukemia the leukemic cells are thought to be blocked in their normal differentiation. The stage of differentiation is the basis for the FAB classification. Induction of cell differentiation is a new and promising development in the treatment of some myeloproliferative diseases. The criteria for cell maturation and differentiation are almost all based on the morphology of the leukemic cells. In this study we tried to specify the maturation stage of the leukemic cells by quantitative enzyme analysis. In the HL60 (promyelocytic) cell line cells we determined the following enzymes: myeloperoxidase; alpha naphthyl acetate esterase; alpha naphthyl butyrate esterase and lactate dehydrogenase. The enzyme profiles obtained after culturing the cells in the presence of the differentiation inducing agents 1:25 dihydroxy vitamin D3 and DMSO were compared with several cytochemical and functional parameters. The results obtained in this study show that quantitative enzyme analysis is a useful tool in the study of myeloid or monocytic differentiation.