Erythroid and granulocyte/macrophage progenitor cells in primary acquired sideroblastic anemia

In order to study the pathogenesis of primary acquired sideroblastic anemia (PASA), bone marrow and/or peripheral blood specimens obtained from four patients with PASA were cultured for erythroid colony‐forming units (CFU‐E), erythroid burst‐forming units (BFU‐E), and granulocyte/macrophage colony‐forming units (GM‐CFU). The number of CFU‐E was markedly decreased in all four patients. CFU‐E colonies consisted exclusively of normal‐appearing erythroblasts, while ringed sideroblasts were observed only in scattered single erythroblasts or in small erythroblast aggregates. In one case, very few BFU‐E colonies containing both normal‐appearing erythroblasts and ringed sideroblasts were detected. In addition, the number of GM‐CFU was significantly decreased in three out of the four cases. These findings may suggest that there are abnormalities in the pluripotent hemopoietic stem cells at least in some cases of PASA.