C3 and type III hypersensitivity disease: Immune complexes are taken up by cells of the reticuloendothelial system (RES) both through interaction of antibody Fc domains with fragment crystallizable gamma (Fcɤ) receptors and interaction of complement-dependent opsonins such as deposited C3 fragments with complement receptors and impairment of these processes can lead to tissue deposition and immune complex disease as reviewed elsewhere [28].