RBCs of AIHA patients show increased phagocytosis compared with RBCs from healthy individuals. (A) RBCs of an AIHA patient with auto-IgG antibodies and RBCs of a healthy control were labeled with DiD and incubated with neutrophils of 2 to 3 healthy donors. Erythrophagocytosis of patient I, III, and VI RBCs was comparable to erythrophagocytosis of anti-GPA-opsonized RBCs from a healthy control. Phagocytosis of RBCs of patient II and V by neutrophils is not significantly increased compared with RBCs of a healthy control. Phagocytosis of RBCs of patient IV by neutrophils is increased compared with RBCs of a healthy control. Error bars denote the standard error of the mean. Asterisks represent highly significant differences (*P < .05, ***P < .001, ****P < .0001). (B) Results of the Coombs test (direct antiglobulin test). All patients were tested positive for IgG and negative for IgM and IgA in the Coombs test performed by diagnostics. Patient II and IV showed low positivity for complement and remaining patients were tested negative for complement (+, positive; −, negative; (+), low positivity). Error bars denote the standard error of the mean.