Examining Inflammatory Effects of Reticulocyte Erythrophagocytosis in Human Macrophage Cultures

Red blood cell (RBC) interaction with phagocytes in the spleen and liver may trigger or attenuate inflammatory responses that could influence innate and adaptive immune responses to RBC antigens. Such interactions are particularly relevant in patients with sickle cell disease (SCD), who have elevated rates of auto- and alloimmunity against RBC antigens. Many phagocyte-expressed pattern recognition receptors (PRRs) are intracellular and recognize nucleic acids. Reticulocytes and recently described mature RBCs abnormally retaining mitochondria have nucleic acids and, upon erythrophagocytosis, can access PRRs and affect inflammatory cytokine production. Here, we describe co-culture experiments of human macrophages and RBC subsets from patients with or without SCD to enable examination of erythrophagocytosis-induced inflammatory cytokine responses.