Surface PDI inhibition induces PS exposure on ECs. (A) Ea.hy926 cells were treated with BD34 anti-PDI or isotype control (10 μg/mL), or 100nM hPDI for 30 minutes and/or ionomycin (Iono, 5μM) for 10 minutes before addition of FXa, FVa, and prothrombin substrate. Normalized thrombin generation after 10 minutes, measured in a chromogenic assay, is represented as fold increase over control samples. Data are mean ± SD of triplicates. ***P < .001, 1-way ANOVA. (B) PDI inhibition-induced enhancement of TF procoagulant activity is sensitive to annexin V treatment (P = .033, unpaired t test). (C) Representative micrographs of annexin V–FITC labeling of PS exposure on EA.hy926 cells treated with IgG1k isotype control, BD34 anti-PDI, or ionomycin. (D) Scatter plot representation of MFI and statistical analysis (1-way ANOVA) of annexin V–FITC labeling of PS exposure (n ≥ 50 per group).