Compstatin analogs attenuate the hemodialysis-associated activation of complement and neutrophils and up-regulation of TF in these cells. Normal blood was recirculated through a hemodialysis simulation system for 2 hours at 37°C. (A) The amounts of C3 cleavage products in plasma isolated from the blood before the beginning of this recirculation (predialysis [Pred]) and at various time points during hemodialysis simulation in the presence of compstatin analogs or control peptide. (B) The induction of TF and (C) CD11b expression in PMNs isolated from the blood before (predialysis [Pred]) and during hemodialysis simulation. The results are presented as ratios of the mean fluorescence intensities (MFI) of the cells stained with TF monoclonal antibodies to the cells stained with the isotype control and analyzed by flow cytometry. Data are representative of 4 independent experiments in panel A and 3 in panels B and C (mean ± SEM). The 2-way analysis of variance test was applied to assess statistical significance of the difference between treatment of blood with compstatin analogs (▴) and the control peptide (■): (A) P < .001, (B) P < .034, and (C) P < .021.