New insights into the pathophysiology and in vivo function of IgG Fc receptors through gene deletion studies.
Fc-receptors for IgG (FcyRs) are critically involved at multiple stages of an immune response, ranging from antigen presentation and regulation of antibody production to the end-stage effector mechanisms of inflammation. IgG autoantibodies that are detectable in the majority of autoimmune diseases are ligands for FcgammaRs. The three classes, FcgammaRI, FcgammaRII, and FcgammaRIII, vary in their antibody affinity, cellular expression and in vivo function. We review the current knowledge on the regulation and diverse functions of the distinct FcgammaRs and describe the evidence of their important immunoregulatory roles in autoimmunity based on recent work in animal models.