Removal of circulating GAS6 by addition of either iMer or anti-GAS6 antibody dampens ADP-induced platelet aggregation. (A) Representative light transmission aggregometry tracings showing inhibition of 1 to 2 mM ADP-induced platelet aggregation in human PRP in the presence of 5 μM iMer (red) or vehicle control (green). Tracings are representative of 2 to 4 independent experiments. (B) Quantitation of 4 independent experiments, median value and interquartile range are shown; ∗∗P < .01, Wilcoxon signed pairs rank test. (C) Representative tracings showing ADP-induced platelet aggregation in the presence of 5 μM iMer (red), vehicle control (green), or 5 μM iMer plus rhGAS6 (blue). Addition of excess GAS6 can partially overcome iMer-mediated inhibition. (D) Summary of 3 experiments; ∗P <.05 for control vs iMer-treated; nsfor other comparisons. (E) Representative tracings of ADP-induced platelet aggregation in the presence of GAS6 antibody (red), vehicle control (green), and GAS6 antibody plus rhGAS6 (blue). (F) Summary of 4 separate experiments, P < .05 for control vs anti-GAS6 antibody treatment; P = ns for other comparisons, Friedman test.