Hematopoiesis is a highly regulated process that, starting
from hematopoietic stem cells (HSCs) with self-renewal
capacity in the adult human bone marrow, is able to generate all different types of mature blood cells. The classical
view of hematopoiesis defines binary branching points from
these HSCs that segregate lineages and direct differentiation
to terminally differentiated functional cell types [1]. However, the described hierarchical model can be complemented
with the emerging data that suggest the existence of
hematopoietic stem and progenitor cells with a continuum
of transitory differentiation stages, including cells with early
lineage priming that generate distinct blood cell types
according to the physiological or pathological environment
[2]