To prevent
anemia in seven small children with congenital
nephrotic syndrome of the Finnish type (age range 1 to 4 years), we gave recombinant human
erythropoietin in a dose up to 150 IU/kg/per week. We then studied the limiting factors during 14 weeks. On a
peritoneal dialysis regimen after
nephrectomy, the patients grew considerably (range +0.1 to 2.2 kg/14 wk; mean + 1.3 kg/14 wk). The amount of blood taken for laboratory studies was estimated. Although the estimated erythrocyte volume increased, the improvement was masked in most patients by enhanced growth. In two patients the target
hemoglobin value of 10 gm/dl was reached, and in three patients transfusions were avoided. The reticulocyte count rose in dose-dependent fashion. In five patients
protein malnutrition was not prevented, although intake of
protein was as recommended. The gradual decrease in serum
ferritin values indicated that mobilization of
iron stores was adequate. Serum
iron values decreased, although in general remaining within normal limits. In six patients the serum
copper concentration was low and in two the serum
aluminum concentration was slightly elevated. Two patients had several episodes of
infection. We conclude that in rapidly growing infants and small children receiving
peritoneal dialysis after
nephrectomy, the maintenance or elevation of the
hemoglobin concentration depends on several limiting and coinciding factors. We speculate that, when
protein is limited, body growth has priority over erythropoiesis. A higher dose of
erythropoietin might have evoked a better response in
hemoglobin concentration but might also have resulted in progression of the
protein deficit.