Effect of growth factors on proliferation of CD34⁺PBSCs in 3-day culture.

(A) CD34⁺PBSCs cultured in medium with only FLT3-L did not proliferate (30% viable). (B) CD34⁺PBSCs cultured in FLT3-L, SCF, G-CSF, TPO, and Pixykine resulted in 95% of cells demonstrating 1 to 4 divisions (more than 90% viable). Colchicine (100 ng/mL)-treated CD34⁺PBSCs served as a control for nondivided cells (open unshaded histogram in panels A and B).