TF and abscess: TFPI-mediated amplification of TF-driven extrinsic coagulation activity interferes with extravasation of E. coli strain XA90 (Massberg et al., 2010), whereas this prothrombotic mechanism appears not to be sufficient to combat S. aureus and pneumococci in the absence of FXII, despite the substantial recruitment of leukocyte to the abscess wall (Fig. 4).