Purpose: We assessed the value of marrow cultures for defining the pathophysiology. diagnosis, and therapeutic response to inimunosuppressive therapy in childhood pure red cell aplasia (PRCA).
Patients and Methods: Patients were evaluated either at diagnosis (n = 23) or at the time of treatment failure (n = 2). Twelve patients had transient erythroblastopenia of childhood (TFC). 4 had Diamont-Blackfan anemia (DBA), and 9 had acquired sustained PRCA (A-Su-PRCA). Bone marrow mononueiear cells were cultured with combination of human recombinant (rhu) erythropoictin (EPO). granulocyte monocyte colony stimulating factor (GM-CSF). granulocyte colony stimulating factor (G-CSF). Interleukin 3 (IL-3). either with or without stem cell factor (SCF). and burst forming unit of erythroid (BFU-E) growth was assessed.
Results: The combination of growth factors without SCF failed to induce any crythropoiesis (BFU-F <10/105 mononuclear cells) in 10 patients (2 with TEC. 2 with DBA. and 6 with A-Su-PRCA). although the growth of erythroid colonies was substantially lower in the remaining patients than in controls (45.5 ± 15.4 versus 91.7 ± 12.7. p <0.05). Addition of SCF restored erythropoiesis in all but 6 patients (5 with A-Su-PRCA and 1 with DBA). Five of 6 nonresponders did not respond to any immunomodulating therapy: of the 5. 3 had or developed some evidence of myelodysplasia.
Conclusion: Our data indicate that in vitro colony studies might prove to be a useful diagnostic tool, because erythropoiesis' poor response to growth factors, including SCF. may suggest the diagnosis of myelodysplasia. Moreover, it may have predictive value: in cases of PRCA. regardless of etiology, poor growth of erythropoietic colonies may predict refractoriness to immunomodulating therapy.