Fig. 1. Scatter plots and bar graph with arithmetic means ± SEM showing annexin-PE binding to O RBCs after incubation with serum/plasma from patients with cold AIHA. Compared to negative controls (A, D, G, and C bar "NC"), phosphatidylserin (PS) exposure was significantly (p < 0.001) increased in the presence of fresh serum (containing complement) from patients with cold AIHA (B, E, H, and C bar "1"). Incubation with patient EDTA plasma (F, and C bar "2") or addition of EDTA to patient serum (I, C bar "3") did not result in an increase of PS exposure. (***) p < 0.001.