WBTF PCA may be induced ex vivo by LPS and can be recovered in the MNC fraction. (A) Samples of whole blood anticoagulated in heparin (▵) or EDTA (▴) were incubated with the indicated concentrations of LPS for 6 hours, after which they were frozen before assay of TF PCA as described in Patients and Methods. (B) WBTF PCA was measured in heparin-anticoagulated whole blood (□) both at baseline and 6 hours after incubation with LPS (1 μg/mL). In parallel samples, MNCs were isolated both at baseline and after a similar incubation with LPS. TF PCA was then assayed in the isolated MNC (▪). The data in each figure are from one experiment that is representative of four such experiments.