Elevated levels of fetal hemoglobin synthesis in infants with bronchopulmonary dysplasia.

A study was devised to determine whether levels of fetal hemoglobin (HbF) synthesis are elevated in infants with bronchopulmonary dysplasia (BPD) when compared with the levels of HbF synthesis found in normal control infants. Twelve infants with BPD, whose postconceptional ages ranged from 40 to 62 weeks, were studied. The mean (+/- SD) gestational age and birth weight was 29 +/- 1.9 weeks and 1289 +/- 376 g, respectively. Elevation infants matched for birth weight, gestational age, and postnatal age served as the control subjects. Blood samples were incubated in an amino acid mixture containing [14C]leucine. The adult hemoglobin and HbF were then separated by column chromatography on diethylaminoethyl-Sephadex. The results demonstrated that the mean (+/- SD) level of HbF synthesis in infants with BPD was significantly higher than that in the control infants (42.6 +/- 22.9% vs 18.8 +/- 12.8%; P less than .01). When levels of HbF synthesis in the infants with BPD and the control infants were compared with data previously reported in normal infants, 7 of the 12 infants with BPD, but none of the control infants, were synthesizing amounts of HbF greater than would be expected for their postconceptional age. The results suggest that cardiopulmonary insufficiency could stimulate HbF synthesis during the first year of life as a result of an erythropoietic response to hypoxemia.