Erythroleukemia: in vitro studies of erythropoiesis

We studied the growth of erythroid burst-forming units (BFU-E) and erythroid colony forming units (CFU-E) from bone marrow and blood in six patients with erythroleukemia. Five patients grew CFU-E, while BFU-E were found in the marrow of two and in the peripheral blood of only one patient. In all cases with colony growth, the numbers of colonies were markedly decreased with respect to normal controls. Patient BFU-E were composed of fewer clusters than those of controls. BFU-E and CFU-E growth was dependent on the addition of erythropoietin to the medium, and no growth was observed in absence of erythropoietin. At present it is not known if the growth obtained is derived from residual normal erythropoietic stem cells or from abnormal erythroid precursors of the leukemic cells.