BONE-MARROW FINDINGS BEFORE AND AFTER TREATMENT WITH RECOMBINANT-HUMAN-ERYTHROPOIETIN IN CHRONIC HEMODIALYZED PATIENTS

The stimulating effect of rHuEPO on erythropoiesis has been shown in s everal studies, using bone marrow cell culture or animal models. To in vestigate the effect of rHuEPO on bone marrow findings in vivo, we stu died the bone marrow cellularity, the myeloid:erythroid (M:E) ratio, a n estimate of the number of megakaryocytes, any cytomorphologic or mat uration abnormalities, and an estimate of the storage iron before and after 3 months of treatment with rHuEPO in 10 chronic hemodialyzed pat ients. Nine patients showed a slight or moderate decrease of erythropo iesis in bone marrow in comparison to normal bone marrow before rHuEPO treatment. The bone marrow cellularity was a mean of 28.5% and decrea sed in 8 out of 10 patients compared to normal values. However, megaka ryopoiesis and granulopoiesis were normal. Three months of treatment w ith rHuEPO had increased erythropoiesis in all 10 patients, including one patient whose bone marrow proved to be normal erythropoiesis on ba seline examination. The M:E ratio was significantly decreased from 3.0 +/- 1.2:1 to 2.4 +/- 1.1:1 (p <0.005). The bone marrow cellularity wa s also increased in 9 patients, except in 1 patient whose specimen was inadequate for diagnosis, after 3 months of treatment with rHuEPO. On baseline examination of bone marrow, iron staining was undetectable i n one, low in one, normal in 2 and high in 5 sections. According to gr ading, iron staining had decreased from 3.1 +/- 1.7 to 2.1 +/- 0.9 (p <0.05). These data suggest that, not only the relative frequencies of erythroid to myeloid series, but bone marrow cellularity decreased in chronic hemodialyzed patients and that rHuEPO could correct these abno rmalities in bone marrow. Also, it seems that we have to pay more atte ntion to supplementing iron beforehand in any use of rHuEPO.