Role of different Fc receptors in the induction of TF expression in PBMCs by the HIT Ab complex. PBMCs were preincubated for 30 minutes with either anti-FcγRI Ab (10 μg/mL), anti-FcγRII Ab (10 μg/mL), or anti-FcγRIII Ab (10 μg/mL) before the addition of control Ab or KKO (100 μg/mL) + heparin (1 U/mL) + PF4 (10 μg/mL). (A) TF activity in PBMCs. (B) MP TF activity in MPs isolated from the cell supernatant fluid. The results are from 3 independent experiments. Complex refers to addition of KKO + PF4 + heparin. ***P < .001.