Neutrophil priming enhances erythrophagocytosis. (A-C) Stimulation of human neutrophils isolated from the blood. Stimuli can enhance phagocytosis of anti-GPA-opsonized RBCs but not of unopsonized RBCs or anti-RhD-opsonized RBCs. (D) CD47 blocking combined with neutrophil priming using LPS enhances phagocytosis by neutrophils. Other stimuli do not have this effect. Error bars denote the standard error of the mean. Asterisks represent highly significant differences (****P < .0001). INF, interferon.