Primary refractory anemia: clinical and laboratory study of erythropoiesis in 16 patients.

Erythropoiesis was studied in vitro in 16 selected patients with primary refractory anemia without excess of blasts who have been followed for an average of 4.8 years. The number of erythroid colonies and bursts grown in vitro from the patients' marrows did not correlate with any parameter of their disease or their prognosis. The response of marrow erythroid precursor cells to erythropoietin was found to be normal. In no case was a serum or IgG inhibitor of erythropoiesis detected either by quantitation of heme synthesized by marrow cells or by the erythroblast cytotoxicity assay. A clinically significant response of the anemia to corticosteroids was noted in three out of 14 patients. Ten patients died during the followup period, eight of them as a consequence of their hematologic disorder. Bone marrow aplasia with pancytopenia developed in six cases, increased number of marrow blasts in two cases, myelofibrosis with myeloid metaplasia in one case and a spontaneous remission in another case. Refractory anemia without excess of blasts is a heterogeneous disorder with variable natural history including evolution into marrow aplasia.