Diminished bone marrow responsiveness to erythropoietin in myelophthisic anemia.

The purpose of this study was to examine a mechanism which might explain the diminished erythropoiesis that occurs when tumor cells invade the bone marrow (myelophthisic anemia). To this end we compared 21 patients with neoplastic bone marrow invasion with seven normal subjects. When erythropoietin was added to bone marrow cell cultures from the normal subjects, the baseline rate of heme synthesis for a specific number of marrow erythroid cells increased 65%. In contrast, in patients with greater than 60% of the marrow replaced by tumor, the marrow cell culture response to erythropoietin was 14% above baseline. A significant inverse correlation was noted between the degree of marrow infiltration with tumor and the stimulation of heme synthesis with erythropoietin. It is proposed that marrow invasion with tumor may result in decreased marrow response to erythropoietin, and hence, diminished red cell production.