['In 38 patients with myelodysplastic syndromes (MDS) the values of serum erythropoietin were measured at diagnosis and compared with the haemoglobin level. A highly significant inverse relationship was found between these two parameters, suggesting that the physiologic mechanism of erythroid progenitor cell recruitment is preserved in MDS. Fourteen transfusion-dependent patients were treated with recombinant human erythropoietin at the dose of 150 U/Kg three times weekly for at least 2 months.'] Do serum erythropoietin level and marrow erythroid infiltration predict response to recombinant human erythropoietin in myelodysplastic syndromes?