Fig. 1

In vivo C3 binding on red cells of PNH patients on eculizumab. a Kinetics of C3 binding on red cells from a representative PNH patient during eculizumab treatment. Before treatment (0 week), no red cell binds C3, whereas starting from 1 week of treatment three populations of red cells are displayed: one population of normal red cells (CD59 + C3−) and two distinct populations of PNH (CD59-negative) red cells, one with (C3+) and one without (C3−) fragments bound on their surface. b Characterization of C3 fragment bound to erythrocytes from PNH patient on eculizumab. The left panel shows the normal (CD59-positive) and PNH (CD59-negative) populations (gated by the elliptic mark). The PNH (CD59-negative) population (see gate in the left panel) has been analyzed with anti-C3d and either anti-C3b (middle panel) or anti-iC3b (left panel). SSC: side scatter