[Preferential synthesis of fetal hemoglobin in in vitro cultures of erythroid precursors from peripheral blood of healthy persons and those with hemoglobinopathies]

Abstract

The synthesis of fetal hemoglobin was investigated in in vitro cultures of erythroid precursors isolated from peripheral blood of normal individuals, newborns and of subjects with different hemoglobinopathies. Synthesis of hemoglobin was assessed by 35s-methionine labeling of cultures and measurement of the radioactivity incorporated into the hemoglobins A2, A, F and S isolated by column chromatography on DE 52 cellulose. The erythroid precursors from most of the studied individuals cultured in in vitro system responded with synthesized an average of 15% of Hb F while cultures from newborns produced an average of 60% of Hb F in comparison of 73% of Hb F in peripheral blood of the same newborns. Erythroid precusors from subjects heterozygotes for beta-thalassemia, heterozygotes for HPFH, and homozygotes for Hb S produced an average of 20%, 43% and 30% of Hb F, respectively, in comparison of 7%, 14% and 9% of Hb F, respectively, present in the RBC of the same individuals. These data support the previously published results (6-11) that erythroid bursts in culture reactivate the structural genes for the gamma chain synthesis.