Murine IFNα is effective treatment in Jak2^VF-induced MPN. (A) Schematic representation of generation of chimeric recipient mice. Purified HSC-enriched populations (lineage^negKit^highSca1⁺) were isolated from Jak2^VF (CD45.2) or Jak2^WT (CD45.1) and injected into lethally irradiated B6xPtprca.F1 (CD45.1/2 double positive) recipient mice. (B) Effects of 4 weeks of daily IFNα on Jak2^VF chimeric mice. Reduced HCT after IFNα (vehicle 76.0 ± 6.9% vs IFNα 65.5 ± 8.1%; P < .05; n = 9-10). (C) Reduced peripheral blood WCC after IFNα (vehicle 13.9 ± 3.7 × 10⁹/L vs IFNα 7.5 ± 3.5 × 10⁹/L; P < .01; n = 9-10). (D) Reduced peripheral blood RCC after IFNα (vehicle 17.8 ± 0.5 × 10¹²/L vs IFNα 14.7 ± 0.7 × 10⁹/L; P < .01; n = 9-10). (E) Reduced hemoglobin (Hb) after IFNα (vehicle 21.4 ± 0.6 g/L vs IFNα 19.4 ± 0.6 g/L; P < .05; n = 9-10). Each data point represents an individual mouse. Data shown are pooled results from 2 independent experiments. (F) Effects of 8 week daily IFNα on Jak2^VF chimeric mice. Reduced HCT after IFNα (vehicle 65.6 ± 5.6% vs IFNα 39.1 ± 0.8%; P < .01; n = 5). (G) Reduced peripheral blood WCC after IFNα (V = vehicle 11.4 ± 0.8 × 10⁹/L vs IFNα 6.7 ± 3.5 × 10⁹/L; P < .01; n = 5). (H) Reduced peripheral blood RCC after IFNα (vehicle 14.0 ± 1.0 × 10¹²/L vs IFNα 8.2 ± 0.2 × 10⁹/L; P < .01; n = 5). (I) Reduced Hb after IFNα (vehicle 20.9 ± 0.5 g/L vs IFNα 11.8 ± 0.3 g/L; P < .01; n = 5). Each data point represents an individual mouse. Results given are mean ± standard deviation. RCC, red cell count; WCC, white cell count.