BINDING-SITES FOR IMMUNE-COMPLEXES CONTAINING IGG IN THE RENAL INTERSTITIUM

In immunologically mediated interstitial renal disease, immunoglobulin and complement are often localized in involved areas of the kidney. The mechanism by which these immune components localize in renal tubulo-interstitial sites is not known. Here, we describe the presence of binding sites for the Fc fragment of IgG in the renal interstitium of man and in a variety of other species. These binding sites were demonstrated in vitro by the specific adherence of IgG-coated sheep or human red blood cells to frozen sections of renal tissue. Binding was specifically blocked by IgG and not by IgM, IgA, or other human and animal proteins. Reagent RBC coated with the (Fab′)2 fragment of IgG were not bound. In contrast to the previously described human glomerular complement receptors, these interstitial IgG-Fc receptors are present in man and in all animal species studied. Such receptor sites may be involved in the deposition of antigen-antibody complexes in renal interstitial areas. © 1979.