Antithrombotic activity of hTM/R6.5 is enhanced by PC supplementation in the setting of plasma PC deficiency. (A) Design of PC deficiency experiments. hTM/R6.5 was infused during the first 25 minutes of the TNF-α washout period, followed by infusion of PC-deficient blood vs control blood (prepared as described in Materials and methods). (B) The anti-thrombotic effect of hTM/R6.5 was reduced in PC-deficient blood and restored with the addition of supplemental PC. Graph shows mean ± SEM, with n = 2 channels for each condition. (C) AUC analysis. *P < .05 vs all other conditions; #, not significant (P = .33); ##, not significant (P = .28). (D) Time curves of the first derivative of fibrin fluorescence intensity demonstrate a delay in peak fibrin deposition but not a reduction in peak height by hTM/R6.5 in PC-deficient WB. Full efficacy is restored with the addition of supplemental plasma PC.