EXPRESSION OF EARLY B-CELL AND NK-CELL MARKERS IN ACUTE MEGAKARYOBLASTIC LEUKEMIA

We report here the case of a 15 month old child with acute megakaryobl astic leukemia confirmed by ultrastructural cytochemical staining for platelet peroxidase. An early B cell marker, CD19, as well as CD56 and CD33 were also found to be positive on the leukemic blasts from this patient. Yet, the platelet peroxidase staining was that typically seen in megakaryoblasts. This novel observation suggests that the surface property of megakaryoblasts is heterogeneous, and that it is important to study both platelet peroxidase staining and immunophenotyping in t he diagnosis of acute leukemia of megakaryocytic origin.