Erythroid precursor cells in primary acquired and secondary sideroblastic anemia

In order to study the changes in erythroid precursor cells in primary acquired and secondary sideroblastic anemia, bone marrow cells from 4 patients with primary acquired sideroblastic anemia (PASA) and 3 patients with refractory anemia with excess of myeloblasts (RAEM) or erythroleukemia associated with an excess of ringed sideroblasts were cultured for erythroid colony-forming units (CFU-E). The number of CFU-E was markedly decreased in all 7 cases, and erythroid colonies formed consisted exclusively of normal-appearing erythroblasts, while ringed sideroblasts were observed in scattered single erythroblasts or in small aggregates of erythroblasts in primary as well as in secondary sideroblastic anemia. These findings may indicate the presence of 2 populations of erythroid progenitor cells in the bone marrow of patients with primary acquired and secondary sideroblastic anemia. A slight to moderate decrease in granulocyte-macrophage colony-forming units (GM-CFU) was observed in 3 cases of PASA. The decrease in GM-CFU, however, was marked in sideroblastic anemia associated with RAEM or erythroleukemia.