Circulating Erythroid Progenitors in the Anemia of Prematurity

Abstract

We studied erythropoiesis in infants with the anemia of prematurity by counting the number of colonies derived from erythroid burst-forming units (BFU-E) in the blood of 11 premature infants before they received transfusions. Colony growth in blood from the infants was compared with growth in blood from adults and umbilical-cord blood from term infants, in the presence of erythropoietin, 0 to 2000 mU per milliliter. Addition of increasing concentrations of erythropoietin resulted in a stepwise increase in the number of colonies derived from BFU-E (P5 cells plated in blood from adults, blood from premature infants, and cord blood, respectively. Although more BFU-E–derived colonies appeared when 200 or 2000 mU were present per milliliter in cultures of the infants' blood and cord blood, the intrinsic responsiveness of BFU-E to erythropoietin was similar in all groups. Although the mean hematocrit was 26 percent, mean serum erythropoietin concentrations (±SD) in the infants (20.7± 10.0 mU per milliliter) were not significantly different from those in the adult controls (24.0±6.5).