Monocyte procoagulant activity.

(A) Monocyte procoagulant activity induced by samples of HIT (●) or control (○) plasma diluted to 10% without (1) or with (2) purified PF4 and heparin. Error bars indicate mean ± 1 SEM of 3 separate experiments. (B) Monocyte procoagulant activity induced by samples of HIT plasma (P1 to P5) or normal plasma (C1 and C2), tested alone (■) or in the presence of PF4 (0.5 μg/mL) without () or with 2 different concentrations of heparin (0.0125 IU/mL,, and 1.25 IU/mL, ▪). Data correspond to the mean of triplicate values in one experiment.