The proliferative state of early erythropoietic progenitor cells (BFU-E) in human umbilical cord blood: low probability of finding BFU-E in DNA synthesis.

We have investigated the proliferative behavior of early erythropoietic progenitor cells (BFU-E) in human umbilical cord blood with hydroxyurea and tritiated-thymidine suicide experiments. Our results indicate that the great majority of these progenitors are normally either in a quiescent state with respect to DNA synthesis or in a prolonged cell cycle experimentally indistinguishable from this state. In this regard, neonatal BFU-E resemble adult circulating BFU-E.