title: Evolution of immunoglobulin deposition in C3-dominant membranoproliferative glomerulopathy.
abstract: BACKGROUND
  Complement 3 glomerulopathy (C3GN) is a newly proposed subcategory of glomerular disease with features including membranoproliferative glomerulonephritis (MPGN), C3-dominant immunofluorescent staining without appreciable immunoglobulin deposition, and electron-dense deposits. Aberrations of alternative complement pathway (AP) have been found in many C3GN patients.
  
  
  METHODS
  A 13-year-old boy presented with edema in association with an upper respiratory infection. Studies demonstrated nephrotic syndrome with hematuria and markedly low C3 and C4. Initial renal biopsy showed MPGN with strong C3 and immunoglobulin deposition. The patient partially responded to immunosuppression. Follow-up biopsies at 10 months and 3 years demonstrated MPGN with strong C3, with little to no immunoglobulin deposition. Based on this and elevated SC5b-9, treatment was changed to eculizumab with further decrease in proteinuria.
  
  
  CONCLUSIONS
  Serial biopsies illustrated marked variability in immunoglobulin deposition in MPGN with persistently strong C3 deposition. Whether this evolution was related to the course of disease or to therapeutic intervention, the pathologic progression documented in this series of biopsies challenges the newly proposed subcategories of MPGN.
authors.affiliation: Department of Medicine, Division of Nephrology & Hypertension, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Kerns
authors.forename: David
authors.initials: D
authors.lastname: Rozansky
authors.forename: Megan L
authors.initials: ML
authors.lastname: Troxell
mesh_terms: D000293:Adolescent; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001706:Biopsy; D003176:Complement C3 / Q000502:physiology*; D003404:Creatinine / Q000097:blood; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology*; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism*; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007668:Kidney / Q000473:pathology; D007677:Kidney Function Tests; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008854:Microscopy, Electron; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D011241:Prednisone / Q000627:therapeutic use; D011507:Proteinuria / Q000209:etiology; D013203:Staphylococcal Infections / Q000150:complications
chemical_list: D000893:Anti-Inflammatory Agents; D003176:Complement C3; D007136:Immunoglobulins; D007166:Immunosuppressive Agents; D003404:Creatinine; D009173:Mycophenolic Acid; D011241:Prednisone; D008775:Methylprednisolone
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