N-acetyl-beta-glucosaminidase activity in normal and malignant leukocytes

An improved cytochemical method demonstrating N-acetyl-beta-glucosaminidase in peripheral blood and bone marrow leukocytes is described. A significant elevation in enzyme activity in circulating monocytes from patients with solid tumor malignancies was observed. In a large series of cases of acute nonlymphocytic leukemia, elevated levels were found in the vast majority of those leukemias that had a predominant monocytic component identified either morphologically or by standard cytochemical methods. This reaction would appear to be useful as a monocyte marker.