Runx1^R188Q/+ peripheral blood cells have reduced lymphocytes and platelets activity. (A-F) Quantification of WBCs (A), B cells (B), and T cells (C), c-kit (D), neutrophils (Gr1⁺Mac⁺, E), monocytes (Mac1⁺Gr1⁻, F) by flow cytometry. (G-J) Quantification of platelet activity after thrombin activation, including levels of fibrinogen receptor (CD41/61) in membrane (G), translocation of P-selectin from alpha granules (H), mepacrine uptake by dense granules (I), and serotonin release from dense granules (J). ∗P < .05, ∗∗P < .005; ns, not significant.