Sleepwalking stem cells

Abstract

In this issue of Blood, Bernitz et al show that granulocyte colony-stimulating factor (G-CSF) selectively mobilizes nondividing hematopoietic stem cells (HSCs).1 A majority of the HSCs remain quiescent after mobilization and ultimately return to the bone marrow without dividing. Thus, G-CSF does not uniformly drive adult HSCs into cycle.