title: Renal involvement in monoclonal (type I) cryoglobulinemia: two cases associated with IgG3 kappa cryoglobulin.
abstract: Renal involvement has been described rarely in monoclonal (type I) cryoglobulinemia, although this complication is frequent among patients with mixed (type II or III) cryoglobulin. We report two patients with glomerulonephritis and monoclonal IgGkappa cryoglobulin. Both patients presented with nephrotic syndrome, microscopic hematuria, and impaired renal function. Hepatitis C serology was negative, bone marrow aspiration was normal, and the renal biopsy specimen showed membranoproliferative glomerulonephritis with glomerular subendothelial deposits of monoclonal IgGkappa. In both cases, circulating cryoglobulin and monotypic tissue deposits were found to be IgG3kappa, suggesting that this isotype may have a particular propensity to cause this type of membranoproliferative glomerulonephritis. Although 18 cases of type I cryoglobulinemia with biopsy-proven glomerulonephritis have been reported to date, this is the first characterization of immunoglobulin heavy-chain isotype in this disease.
authors.affiliation: Service de Néphrologie, Laboratoire d'Immunologie, INSERM U507, Hôpital Necker, Paris, France. alexandre.karras@sls.ap-hop-paris.fr
authors.forename: Alexandre
authors.initials: A
authors.lastname: Karras
authors.forename: Laure-Hélène
authors.initials: LH
authors.lastname: Noël
authors.forename: Dominique
authors.initials: D
authors.lastname: Droz
authors.forename: Dominique
authors.initials: D
authors.lastname: Delansorne
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Saint-André
authors.forename: Pierre
authors.initials: P
authors.lastname: Aucouturier
authors.forename: Marie-Alexandra
authors.initials: MA
authors.lastname: Alyanakian
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Grünfeld
authors.forename: Philippe
authors.initials: P
authors.lastname: Lesavre
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal / Q000097:blood*; D003449:Cryoglobulinemia / Q000145:classification* / Q000473:pathology; D015432:Glomerulonephritis, Membranoproliferative / Q000097:blood / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007145:Immunoglobulin kappa-Chains / Q000097:blood*; D007668:Kidney / Q000098:blood supply / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains