Cytochemical and immunological phenotying of acute nonlymphoblastic leukemia in Thai patients.

Using morphology and cytochemical reaction, we could subclassify-according to FAB classification, 51 of our 56 cases of acute nonlymphoblastic leukemia (ANLL) as M1-M5. Five cases were undifferentiated. Using the immunophenotypic method, we could subclassify 51 of these patients as M1-M4. In addition, 3 cases of undifferentiated leukemia by the prior method were each classified as M1, M3, and myelo-megakaryoblastic leukemia. Correlation of ANLL subtype classification according to each method was not good. However, combination of both methods, using immunophenotypic analysis as a supplement would better subclassify the disease. One of the remaining 2 cases of undifferentiated leukemia was also shown to be myelo-megakaryoblastic leukemia by a positive platelet peroxidase reaction by ultrastructural cytochemistry. Thus, combination of these 3 methods could diagnose and subclassify 55 of the 56 cases (98%) of our ANLL patients.