The HIT Ab complex induces release of TF⁺ MPs from PBMCs. PBMCs were incubated for 6 hours at 37°C under the same experimental conditions as outlined under Figure 1B. (A) MPs were isolated from the cell supernatant fluid, and MP TF activity was measured with a 2-stage chromogenic assay. (B) The number of TF⁺ MPs was determined with flow cytometry–based detection of TF⁺/CD14⁺ events. The top plot shows the number of MPs from PBMCs incubated with media alone (control), and the bottom plot shows the number of MPs from PBMCs incubated with the HIT Ab complex. Increases were seen in the number of TF⁺/CD14⁺ MPs and the MFI of TF (later not shown). Results are from 5 independent experiments. ***P < .001 and **P < .01 compared with control.