Mechanisms of antibody-sensitized RBC destruction in w-AIHA. Erythrocytes coated by warm-reacting IgG are bound by spleen macrophages carrying Fcγ receptors for the IgG heavy chain, and they are either phagocytosed or have part of their membrane removed, in which case they form microspherocytes subject to further destruction during their next passage through the spleen. ADCC, mediated by cytotoxic CD8⁺ T cells (Tc) and NK cells, is also contributing to extravascular hemolysis preferentially in the spleen and lymphoid organs. When either a high concentration of IgG or IgG with high affinity to complement is bound to the erythrocytes, complement (C1q) is bound and gets activated toward C3b. C3b-opsonized RBCs are next phagocytosed by liver macrophages that carry C3b receptors.