Idiopathic membranous glomerulonephritis is associated with altered patterns of self-reactive IgM and IgG antibody repertoires

Idiopathic membranous glomerulonephritis (MGN) is an immune complex nephrop athy characterized by the subepithelial deposition of immunoglobulin (Ig)G. The pathogenesis of the disease remains largely unknown, but recent eviden ce suggests that human MGN may involve an autoimmune component. In the pres ent study, we have analyzed the IgM and IgG antibody repertoires of patient s with MGN towards self- and nonself-antigens using a technique of quantita tive immunoblotting on a panel of whole human tissue or solubilized bacteri al cell extracts as sources of antigens. Data were compared by means of mul tiparametric statistical analysis. We demonstrate that the antibody reperto ires of self-reactive IgM and IgG in plasma of patients with MGN exhibit si gnificantly altered patterns of reactivity, as compared with those of healt hy controls. In contrast, multiparametric statistical analysis does not dis criminate the reactivity patterns of IgM and IgG in plasma of patients and healthy controls towards nonself antigens. These observations indicate that a failure in the regulation of physiological self-reactivity is associated with immune complex nephropathy in MGN.