Advances in the understanding of the Fc gamma receptors-mediated autoantibodies uptake

Receptors for the Fc fragment of immunoglobulin G (FcγRs) are important molecules not only to mediate and control the effectors' functions of IgG antibodies, but they also control the autoimmunity-tolerance balance in the periphery. In humans, three different types of FcγRs, belonging to the Ig gene superfamily, have been identified; FcγRI (cluster of differentiation (CD64), FcγRII (CD32) and FcγRIII (CD16). A wide range of inflammatory and autoimmune diseases, such as vasculitis, glomerulonephritis, and autoimmune hemolytic anemia, seems to be mediated, in part, by FcγRs. Recent findings supposed that, under certain conditions, FcγRs are involved in the penetration of antibodies into cells and FcγRs constitute one of the main effector mechanisms through which autoantibodies exert their action. In this review, we concentrate on the role of human FcγRs in autoantibodies penetration and summarize the current knowledge on the structure, ligand binding capacity and their role in autoimmunity and pathogenic effect of autoantibodies.