Increasing the S100A9:S100A8 ratio in vivo significantly impairs AML progression and induces cell differentiation. (A) Schematic illustration of experimental design. (B) Survival curves of secondary H9M1 AML recipients treated with pAb anti-S100A8, mAb anti-S100A9, or control IgGs at 10 mg/kg of body weight until moribund (data are from 1 of 3 independents experiments). (C) Evolution of weight during AML progression of mice treated with anti-S100A8 or control antibodies (n = 8). (D) Percentage of leukemia cells in peripheral blood (PB) in control and anti-S100A8–treated leukemic mice after 4 weeks posttransplantation. (E) Flow cytometry analyses of AML cells from representative mice treated with anti-S100A8. Contour plots are gated on EGFP⁺ cells. (F) Representative May-Grunwald-Giemsa–stained cytospins of AML cells from anti-S100A8–treated mice showing signs of granulocytic differentiation. Scale bars, 20 µm. (G) Cell-cycle profiles of BM cells from control and anti-S100A8 recipients (n = 5). Results are represented as the mean ± standard error of the mean. P value was determined by Student t test. *P < .05 or ***P < .001 from 3 independent experiments.