Flow Cytometric Analysis of Platelet Phagocytosis. hMDMs were incubated with an excess of fluorescently labeled platelets for 45 min in RPMI media alone (white bars) or containing 10% autologous human serum (striped bars). Macrophage fluorescence was measured by flow cytometry and the average percentage of FL1-positive macrophages after removal of adherent platelets are shown for 3 independent experiments for each sample. Data for control samples are repeated in each panel, and compared to treatment with (A) latrunculin (1 ug/ml), (B) thrombin (0.1 U/ml), or (C) fucoidan (250 ug/ml). Statistically significant differences are indicated with their corresponding p-values. The addition of 10% serum did not result in any statistically significant difference (NS).