Human neutrophil Fcgamma receptors initiate and play specialized nonredundant roles in antibody-mediated inflammatory diseases

Inflammation mediated by antibody-antigen complexes contributes to autoimmune diseases. Mice deficient in the common Fcgamma-chain are protected from IgG-mediated glomerulonephritis and the reverse passive Arthus (RPA) reaction and FcR-bearing macrophages, and mast cells have been assigned primary roles in these processes. Here we demonstrate that neutrophil-selective transgenic expression of the two uniquely human neutrophil Fc gamma receptors (FcgammaRs), FcgammaRIIA and FcgammaRIIIB, in Fcgamma-chain-deficient mice restored susceptibility to progressive glomerulonephritis and the cutaneous RPA reaction. FcgammaRIIIB and FcgammaRIIA mediated neutrophil accumulation, whereas FcgammaRIIA alone promoted organ injury. In a model of soluble immune complexes deposited within the vasculature, FcgammaRIIIB was responsible for neutrophil slow rolling and adhesion whereas in the cremaster RPA, induced by both vascular and tissue soluble immune complexes, FcgammaRIIA predominated. Thus, human FcgammaRs on neutrophils serve as molecular links between antibody and immunological disease, with FcgammaRIIA promoting tissue injury and FcgammaRIIIB and FcgammaRIIA displaying specialized context-dependent functions in neutrophil recruitment.