[In vitro effects of high titers of recombinant human erythropoietin on the bone marrow erythroid progenitors in patients with aplastic anemia].

To investigate the role of erythropoietin in aplastic anemia, the effects of high titers of recombinant human erythropoietin (rh-Ep) on CFU-E and BFU-E in patients with aplastic anemia were studied in vitro. Colony assays were performed by methylcellulose culture methods added with 1 to 500 units of rh-Ep. In normal bone marrow, the maximum CFU-E colony formation was observed at 2 to 5 units of rh-Ep, and BFU-E at 2 to 10 units. Colonies did not increase by addition of higher titer of rh-Ep to the cultures. In aplastic anemia, the numbers of CFU-E and BFU-E were low at 2 units of rh-Ep in culture system. In most patients with aplastic anemia studied, erythroid colonies were increased in accordance with the increase of rh-Ep added to cultures. These results suggest that the administration of high titers of rh-Ep in vivo may be useful for the improvement of anemia in aplastic anemia.