Simultaneous demonstration of peroxidase and lysozyme activities in leukemic cells.

A simple cytochemical and cytobacterial method for the simultaneous demonstration of peroxidase and lysozyme (muramidase) activities in individual cells was devised. In characterization of myeloid and monocyte series, the combination of these myeloid- and monocyte-specific enzymes not only was more informative than a single enzyme but made it easier to differentiate acute myelomonocytic leukemia, with higher lysozyme activity, from acute myeloid leukemia, with higher peroxidase activity. Acute lymphocytic leukemia had no lysozyme or peroxidase activity.