Characterization of blast cells in acute nonlymphoid leukemias by consecutive cytochemical reactions

Blast cells of 12 acute nonlymphoid leukemias have been investigated by consecutive application on the same preparation of three cytochemical reactions: alpha-naphthylacetate esterase, AS-D-choroacetate esterase and PAS. A fourth reaction (alpha-naphthylbutyrate esterase) was added in some preparations for a more detailed definition of the monocytoid-oriented cells. The cytochemical techniques were further combined with NaF inhibition and with the cytobacterial test for muramidase. The combined cytochemical approach allowed the identification of most of the blast cells, according to an empirically determined positivity to one or more reactions, and proved to be particularly valuable in classifying the cells after chemotherapy.