Proliferative activity of undifferentiated cells (blast cells) in preleukaemia

Undifferentiated cells (blast cells) in preleukaemic states show labelling indices comparable to those of leukaemic blast cells. Since this cell population can remain constant over months or even years, a steady state must exist between the production of blast cells and cell death. It is more likely, however, that in preleukaemic conditions, blast cells may differentiate to morphologic 'normal' haemopoietic cells. The fact that the latter show an impaired cell proliferation supports the view that they derive from an affected stem cell compartment.