Number and half-life of circulating human platelets after donor-derived platelets or megakaryocytes were infused into NSG mice. (A) 4 × 10⁸ donor-derived (dd) human platelets or 3 × 10⁶ CD34⁺ megakaryocytes were infused into NSG mice. At each time point, peripheral blood was withdrawn to measure circulating human platelet (hPlts) numbers relative to murine platelets after staining with hCD41 and mCD41 antibodies. Mean ± 1 SD is shown. N = 3 per arm. ∗∗∗P ≤ .001 by 1-way ANOVA. (B) Same as in panel A, but for 9 × 10⁶ infused mCherry⁺ shNT- and shRX-megakaryocytes. N = 3 per arm. ∗P ≤ .05 and ∗∗P ≤ 0.01 by 1-way ANOVA comparing shNT-platelets released vs shRX-platelets released. (C) Similar to panel B, but after 9 × 10⁶ of shNT- or shRX-megakaryocytes were infused and shown to display a drop from peak platelet count, with the 50% and 25% levels indicated. N = 3 per arm. ∗P ≤ .05 by 1-way ANOVA comparing shNT-platelets released vs shRX-platelets released.