Increased GPIIb/IIIa activation and CD62P exposition in resting platelets in patients with sepsis or COVID-19. Characteristics of healthy control participants (ctrl) and patients with infection (inf), sepsis, or COVID-19 are displayed on hospital/ICU admission day (t1) and days 4 to 7 (t2).Platelet counts (A), mean platelet volume (MPV) (B), and platelet count vs MPV (C) are displayed. Platelet preactivation due to GPIIb/IIIa activation (D-E) or CD62P exposure (F-G) was assessed under resting conditions by flow cytometry. Events >2% threshold applied for healthy donors are displayed in panels D and F. Relative GeoMFI are shown in panels E and G. (H-I) Quadrant analysis of CD62P and PAC-1+ events under resting conditions. Panels A-C show reference ranges as dashed lines. Panels A and B display median, panels D-G show median ± 95% confidence interval (CI), and panel I shows mean ± 95 CI. Differences were analyzed using the Kruskal-Wallis test. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001, ∗∗∗∗P < .0001. APC, allophycocyanin; FITC, fluorescein isothiocyanate; GeoMFI, geometric mean fluorescence intensity; ns, not significant; PLT, platelet.
