title: Proliferative glomerulonephritis with monoclonal IgG deposits.
abstract: Dysproteinemias that result in monoclonal glomerular deposits of IgG are relatively uncommon. Here, we report the largest series of proliferative glomerulonephritis with monoclonal IgG deposits, a form of renal involvement by monoclonal gammopathy that mimics immune-complex glomerulonephritis. We retrospectively identified 37 patients, most of whom were white (81%), female (62%), or older than 50 yr (65%). At presentation, 49% had nephrotic syndrome, 68% had renal insufficiency, and 77% had hematuria. In 30% of the patients, we identified a monoclonal serum protein with the same heavy- and light-chain isotypes as the glomerular deposits (mostly IgG1 or IgG2), but only one patient had myeloma. Histologic patterns were predominantly membranoproliferative (57%) or endocapillary proliferative (35%) with membranous features. Electron microscopy revealed granular, nonorganized deposits, and immunofluorescence demonstrated glomerular deposits that stained for a single light-chain isotype and a single heavy-chain subtype, most commonly IgG3kappa (53%). During an average of 30.3 mo of follow-up for 32 patients with available data, 38% had complete or partial recovery, 38% had persistent renal dysfunction, and 22% progressed to ESRD. Correlates of ESRD on univariate analysis were higher creatinine at biopsy, percentage of glomerulosclerosis, and degree of interstitial fibrosis but not immunomodulatory treatment or presence of a monoclonal spike. On multivariate analysis, higher percentage of glomerulosclerosis was the only independent predictor of ESRD. Only one patient lacking a monoclonal spike at presentation subsequently developed a monoclonal spike and no patient with a monoclonal spike at presentation subsequently developed a hematologic malignancy. We conclude that proliferative glomerulonephritis with monoclonal IgG deposits does not seem to be a precursor of myeloma in the vast majority of patients.
authors.affiliation: Department of Pathology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA. sn386@columbia.edu
authors.forename: Samih H
authors.initials: SH
authors.lastname: Nasr
authors.forename: Anjali
authors.initials: A
authors.lastname: Satoskar
authors.forename: Glen S
authors.initials: GS
authors.lastname: Markowitz
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Valeri
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Appel
authors.forename: Michael B
authors.initials: MB
authors.lastname: Stokes
authors.forename: Tibor
authors.initials: T
authors.lastname: Nadasdy
authors.forename: Vivette D
authors.initials: VD
authors.lastname: D'Agati
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000276:immunology; D001706:Biopsy; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D015432:Glomerulonephritis, Membranoproliferative / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007155:Immunologic Factors / Q000627:therapeutic use; D007678:Kidney Glomerulus / Q000276:immunology / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010265:Paraproteinemias / Q000276:immunology* / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D007155:Immunologic Factors