AML blasts can scavenge TPO by virtue of their MPL expression, leading to inadequate cytokine levels. (A) Peripheral blood counts are shown as a function of bone marrow blast count, in patients with newly diagnosed AML at a single medical center (N = 223). Pearson product-moment correlation coefficient is stated. (B) Scatter plot depicting relationship between serum TPO concentration and platelet count (N = 52). Pearson product-moment correlation coefficient is stated. Selected potential scavenger AML cases (low platelets, low TPO; group A) are highlighted as gray squares and control AML cases (group B) as white squares. (C) Waterfall plot shows MPL mean normalized expression in individual patients identified by their unique ID below; box-and-whiskers plot shows comparison between groups A and B. (D) Histograms show MPL mean fluorescent intensity (MFI) on blasts (red line) compared with lymphocytes as internal control (blue line). MFI ratio blast-to-lymphocyte is stated. The 2 upper panels show potential scavenger cases; the 2 bottom panels show controls. Data are representative of N = 12. (E) Scatter plot depicting correlation between flow cytometry MFI and quantitative polymerase chain reaction mean normalized expression (N = 12). (F) TPO clearance after 2 hours of incubation of cells in medium supplemented with 100 pg/mL TPO (N = 4-6 per group). One-way ANOVA, P = .001. (G) Schematic representation of in vivo xenotransplantation experiments. (H) Scatter plot depicts huTPO serum concentration in the xenotransplantation setting by donor-engraftment status. Average engraftment level in the respective groups is stated. N = 3 per group MPL^hi and group MPL^lo for primary AML samples/patients. N = 3-4 per group for murine recipients. One-way ANOVA, P < .0001. ANC, absolute neutrophil count.