Immunoglobulin G (IgG)-mediated activation of complement and IgG Fc receptors (FcγRs)
are important defense mechanisms of the innate immune system to ward off infections.
However, the same mechanisms can drive severe and harmful inflammation, when IgG
antibodies react with self-antigens in solution or tissues, as described for several
autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, and
immune vasculitis. More specifically, IgG immune complexes (ICs) can activate all three …