Complement deposition and antibody binding on RBCs at baseline and after treatment. (A-D) Baseline deposition of C3, IgG, IgM, and IgA on RBCs as analyzed by flow cytometry. (A-C) C3 deposition and IgG and IgM binding is significantly increased in patients with AIHA compared with HCs. (D) IgA binding is not increased compared with the HCs, which were comparable to background geometric mean fluorescence intensity (MFI) except for 1 individual. (E) C3 deposition on RBCs is significantly reduced at 12, 24, and 48 hours compared with baseline in the trial participants. All data are expressed as a scatter plot with median + IQR. Significance was tested using the Mann-Whitney test (A-D) and 1-sample Wilcoxon test (E). ∗P ≤ .05, ∗∗P ≤ .01, ∗∗∗P ≤ .001. Ctrl, control; ns, not significant.