Effect of complement inhibitors on aHUS serum-induced C3 and C5b-9 deposition on ADP-activated HMEC-1. (A-B) Effect of selective inhibitors of the alternative pathway of complement, an anti-CFB antibody (anti-CFB, 150 μg/mL), the CR2-FH fusion protein (CR2-FH, 150 μg/mL and 300 μg/mL), and a CFH concentrate from human plasma (CFH conc, at levels comparable to those of normal human serum, 230 μg/mL) on C3 deposition induced on ADP-activated HMEC-1 by serum from 3 patients with aHUS and CFH mutations studied in remission in 3 independent experiments. (C) Effect of terminal complement pathway inhibitors, an anti-C5 minibody (anti-C5, 135 μg/mL), or an anti-C7 goat polyclonal antibody (anti-C7, 350 μg/mL) or eculizumab (Ecu, 150 μg/ml) on C5b-9 deposition induced on ADP-activated HMEC-1 by serum of patients with aHUS studied in remission. Data are from 3 different experiments in 3 patients (CFH mutations, n = 2; C3 mutation, n = 1) and 3 controls. (D) Effect of 3 doses of eculizumab (Ecu; 100, 50, or 25 μg/mL) on C5b-9 deposition on ADP-activated HMEC-1 induced by serum of patients with aHUS studied in the acute phase before any treatment. Data are from 3 different experiments in 3 patients (without mutations or anti-CFH antibodies) and 3 controls. Data are mean ± SE. °P < .001, °°P < .01, °°°P < .05 vs control serum; *P < .001, **P < .01, ***P < .05 vs aHUS serum untreated. Control range: dotted horizontal areas. ctr, control.