Low doses of RG7112 and Peg-IFNα 2a in combination promote MPN CD34⁺ cell apoptosis. (A) Flow cytometric analysis showing the results of Annexin V staining on normal, PV, and PMF CD34⁺ cells after 2 days of treatment with 200 nM of RG7112 or 200 ng/mL of Peg-IFNα 2a alone or in combination. (B) Histogram showing the effects of these treatments on the CD34⁺/AnnexinV⁺ cell population in normal (n = 5), PV (n = 8), and PMF (n = 6) CD34⁺ cells after 2 days of treatment with 200 nM of RG7112 or 200 ng/mL of Peg-IFNα 2a alone or in combination. (C) Histogram showing the effects of 4 days of drug treatment on PV CD34⁺/cleaved caspase-3⁺ cells (n = 6, P < .05).