In vitro study of erythropoiesis in patients with aplastic anemia and myelodysplastic syndromes: a possible tool for prospective determination of the clinical effectiveness of growth factors.

Effects of recombinant human erythropoietin (rhEpo) and the combination of recombinant human interleukin-3 (rhIL-3) or recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) with rhEpo on erythroid colony formation were examined in vitro in 13 patients with aplastic anemia and 16 with myelodysplastic syndromes (MDS). The methylcellulose cultures of marrow cells from normals and the patients yielded no erythroid colonies in the absence of rhEpo. In normals, CFU-E and BFU-E colony formation was significantly increased by adding either rhIL-3 or rhGM-CSF with rhEpo, compared with rhEpo alone, and rhIL-3 was more potent than rhGM-CSF to form colony-forming units and burst-forming units of erythroid (CFU-E) (BFU-E) colonies. By adding rhIL-3 with rhEpo, CFU-E colony formation was increased in half of patients with RA, compared with rhEpo alone, and by rhGM-CSF, in one third. Approximately one third or one fourth of the patients with MDS showed increased BFU-E colonies when rhIL-3 or rhGM-CSF were added to rhEpo. Cultures containing rhIL-3 or rhGM-CSF with rhEpo yielded larger numbers of BFU-E colonies in half of the patients with nonsevere aplastic anemia than those containing rhEpo alone. These observations suggest that the combination of these growth factors, especially rhIL-3 with rhEpo, is applicable to the treatment of anemia in some patients with aplastic anemia and MDS.