Aplastic anemia: assessment of myeloid progenitor cells in the bone marrow and blood provides prognostic information.

15 patients with aplastic anemia were prospectively followed after having measurements of myeloid progenitor cells in bone marrow and blood. Treatment included androgens, low or high dose steroids and standardized supportive care. The median length of survival was 5.8 months. When patients were grouped according to the numbers of myeloid progenitor cells present in their blood and bone marrow, we found that the survival length of aplastic patients with higher progenitor cell numbers was prolonged when compared to that of patients with lower numbers of these cells. The prognostic information obtained from such in vitro cultures was particularly indicative when the patients were grouped according to 'growth' and 'no growth': the absence of colony-forming myeloid stem cells was associated with survival times significantly shorter than those of patients whose cells maintained their colony-forming capacity. Besides initial numbers of myeloid progenitor cells, only initial numbers of granulocytes were related to survival length. Thus, the measurement of myeloid progenitor cells in bone marrow and blood can be of prognostic value in patients with aplastic anemia.