SERUM ERYTHROPOIETIN LEVELS FOR PREDICTING BONE-MARROW RECOVERY FOLLOWING CHEMOTHERAPY IN LEUKEMIA

To investigate whether serum erythropoietin (EPO) levels are influence d by the intensity of bone marrow erythroid activity, we used a radioi mmunoassay (Nippon DPC Co., Japan) to study EPO levels in three acute leukaemia patients during treatment with intensive chemotherapy. We al so measured the reticulocyte count and reticulocyte maturity using an automated reticulocyte analyser (Sysmex R-2000) to detect erythropoiet ic activity. From the day after the initiation of chemotherapy, EPO le vels increased markedly without any change in Hb levels, suggesting th at some other mechanism was regulating serum EPO. A decrease in EPO af ter chemotherapy was accompanied by an increase in high fluorescence r atio, an index of immature reticulocytes, but the actual increase in t he reticulocyte count was delayed for 3-4 days after this. These findi ngs suggest that the decrease in serum EPO levels was closely related to the early stage of red cell production and that EPO levels may be a useful marker for the recovery of erythropoietic activity after chemo therapy.