Localization of C3d in renal tissues of patients with membranous nephropathy and IgA nephropathy

Cases without glomerular deposition of C3c in spite of deposition of immunoglobulin are known to occur in membranous nephropathy or IgA nephropathy. When the deposition of C3d as a C3 breakdown product or H as a control protein was investigated by immunofluorescence in such cases, depositions of C3d and H were found in all cases. From the results obtained, it is considered that C3 underwent decay due to the action of control protein, etc., and was converted to C3d in spite of the involvement of complement at that localization in the kidneys.