GROWTH-STIMULATORY EFFECT OF THROMBOPOIETIN ON THE BLAST CELLS OF ACUTE MYELOGENOUS LEUKEMIA

Thrombopoietin stimulated blast colony formation in 11/20 acute myelog enous leukaemia (AML) patients studied. The FAB subtypes of the blasts responding to thrombopoietin were not restricted to those of the mega karyocyte lineage, but also included M1-M5 AML blasts. The morphology of colony cells produced by megakaryocytic blasts showed megakaryocyto id features, whereas colony cells produced by M1-M5 AML blasts remaine d myeloblasts. An increase in CD41 was observed in the cells of coloni es produced by blasts from the megakaryocyte lineage involving leukaem ia and chronic myeloid leukaemia in blastic crisis. Thrombopoietin rec eptor was observed on leukaemic blasts which formed colonies following incubation with thrombopoietin.