Fig. 1.

Increased platelet activation in COVID-19 patients and that stimulated by SARS-CoV-2. a Platelet counts and D-dimer levels of patients with severe/fatal and moderate COVID-19 are shown as the medians and interquartile ranges. The normal range of platelet count (150–400 × 10⁹/L) is shaded, and the upper limit value of D-dimer (0.5 mg/L) is indicated with dotted line. Soluble P-selectin levels (sP-selectin), soluble GPVI levels (sGPVI), PF4, and RANTES in plasma of patients with severe/fatal or moderate COVID-19, and healthy controls were measured through ELISA. b Platelet activation was investigated using platelets from healthy donors incubated with SARS-CoV-2, thrombin, or virus culture medium (Mock) for 3 h at 37 °C. P selectin surface translocation was measured using flow cytometry and results using platelets from two healthy donors are shown. c Levels of GPVI, PF4, and RANTES in the incubation supernatants were determined through ELISA. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001