PF4 and ischemic stroke: To further address immunothrombosis in ischemic stroke, we measured markers of coagulation (D-dimer; Figure 2A), platelet activation (platelet factor 4 [PF4]; Figure 2B), neutrophil activation (calprotectin; Figure 2C), NET formation (H3cit, Figure 2D; and MPO-DNA complexes, Figure 2E), and NET degradation potential (DNase activity; Figure 2F) in plasma from matched healthy donors and stroke patients (Supplemental Table 1).