title: Membranous nephropathy associated with IgG4-related disease.
abstract: Immunoglobulin G4 (IgG4)-related systemic disease is a rare condition characterized by high levels of circulating IgG4 and IgG4-positive plasma cell infiltrates in various organs, including the pancreas, salivary glands, biliary tract, liver, lung, and kidney. We describe a case of a 54-year-old man with IgG4-related systemic disease presenting with autoimmune pancreatitis and Mikulicz disease. Steroid therapy decreased circulating IgG4 levels and promoted regression of clinical signs. Thereafter, an increase in serum IgG4 values was followed by the occurrence of nephrotic-range proteinuria. Kidney biopsy showed membranous nephropathy with no IgG4-positive cell infiltrates. A search for circulating immune complexes was negative, and antibodies against M-type phospholipase A(2) receptor could not be detected. Western blot analyses identified circulating IgG3 reacting with superoxide dismutase 2. This case suggests that membranous nephropathy represents an additional renal manifestation of IgG4-related systemic disease, with a pathogenesis possibly associated with neoproduction of autoantibodies targeting podocyte antigen(s).
authors.affiliation: Mario Negri Institute for Pharmacological Research, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, Ranica, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cravedi
authors.forename: Mauro
authors.initials: M
authors.lastname: Abbate
authors.forename: Elena
authors.initials: E
authors.lastname: Gagliardini
authors.forename: Miriam
authors.initials: M
authors.lastname: Galbusera
authors.forename: Simona
authors.initials: S
authors.lastname: Buelli
authors.forename: Ettore
authors.initials: E
authors.lastname: Sabadini
authors.forename: Maddalena
authors.initials: M
authors.lastname: Marasà
authors.forename: Laurence H
authors.initials: LH
authors.lastname: Beck
authors.forename: David J
authors.initials: DJ
authors.lastname: Salant
authors.forename: Ariela
authors.initials: A
authors.lastname: Benigni
authors.forename: Vivette
authors.initials: V
authors.lastname: D'Agati
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Remuzzi
mesh_terms: D015433:Glomerulonephritis, Membranous / Q000276:immunology*; D006801:Humans; D006942:Hypergammaglobulinemia / Q000150:complications*; D007074:Immunoglobulin G; D008297:Male; D008875:Middle Aged; D009404:Nephrotic Syndrome / Q000276:immunology
chemical_list: D007074:Immunoglobulin G