Inhibition of TF and thrombin decreases the endothelial thromboinflammatory response to VITT serum. (A) Left: kinetics of factor Xa generation in endothelial cells after incubation with media (untreated) or TNF-α in the presence of isotype control antibody or inhibitory anti-TF antibody 5G9. Right: factor Xa generation (nanomoles per minute [nM/min]) of TNF-α–treated HUVECs in the presence of isotype control or 5G9 antibody. A paired t test was used for comparisons. (B) Platelet fluorescence area per field, neutrophil count per field, and fibrin fluorescence area per field after a 15-minute blood perfusion in the Endo-chip after treatment with VITT ELISA positive or VITT ELISA negative sera in the presence of isotype control or 5G9 antibody. VITT ELISA positive n = 6 (patients 2, 4, 5, 6, 9, 13), VITT ELISA negative n = 6 (patients 2, 4, 9, 10, 13, 14). A paired t test was used for comparison. (C) Platelet fluorescence area per field, neutrophil count per field, and fibrin fluorescence area per field following 15 minutes perfusion with blood containing vehicle control or the thrombin inhibitor argatroban in the Endo-chip after treatment with VITT serum with 25 μg/mL PF4 added. VITT ELISA positive sera n = 3 (patients 4, 6, 13). A paired t test was used for comparison.