title: Fibrillary glomerulonephritis and immunotactoid (microtubular) glomerulopathy are associated with distinct immunologic features.
abstract: BACKGROUND
  The clinical relevance of distinguishing two types of glomerulonephritis (GN) with non-amyloid organized immunoglobulin (Ig) deposits-fibrillary GN (FGN) and immunotactoid (microtubular) GN (IT/MTGN)-on the basis of ultrastructural organization, is debated.
  
  
  METHODS
  Twenty-three patients with organized glomerular Ig deposits were classified into two groups based on the fibrillar or microtubular ultrastructural appearance of the deposits. Kidney biopsy samples were studied by immunofluorescence microscopy, using anti-light chain conjugates (all cases) and anti-IgG subclass conjugates (13 patients). In each group, we studied clinicopathological features, associated monoclonal gammapathy (detected by immunoelectrophoresis and/or immunoblot) or B-cell lymphoproliferative disease, effects of chemotherapy and long-term renal outcome.
  
  
  RESULTS
  In 14 IT/MTGN and 9 FGN patients, clinical symptoms [hypertension, nephrotic syndrome (NS) and hematuria] and the mean diameters of the substructures were similar. In 13 IT/MTGN patients, glomerular (IgG1, 2 or 3) deposits were monotypic (kappa, 7 cases; lambda, 6 cases). Glomerular deposits were associated with a monoclonal Ig of the same isotype in eight patients, detected in the serum (5 cases), and/or in the cytoplasm of lymphocytes (4 cases), and with lymphoproliferative disease in seven patients. The ultrastructural features of monoclonal Ig inclusions in lymphocytes were similar to those of glomerular microtubular deposits. In contrast, none of the FGN patients presented lymphoplasmocytic proliferation or paraproteinemia. Glomerular Ig deposits were polyclonal in eight cases and contained IgG4 in all three cases studied. Although patient and renal survival did not differ significantly between the two groups, chemotherapy led to remission of NS in ten IT/MTGN patients, with parallel improvement in hematological parameters.
  
  
  CONCLUSIONS
  The identification of ultrastructural patterns in these nephropathies is important. GN with organized microtubular monoclonal deposits (GOMMID) probably accounts for a large proportion of immunotactoid (microtubular) GN cases.
authors.affiliation: Department of Nephrology, and Laboratory of Immunology and Immunopathology(CNRS ESA 6031), University Hospital, Poitiers, France. f.bridoux@chu-poitiers.fr
authors.forename: Frank
authors.initials: F
authors.lastname: Bridoux
authors.forename: Valerie
authors.initials: V
authors.lastname: Hugue
authors.forename: Olivier
authors.initials: O
authors.lastname: Coldefy
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Goujon
authors.forename: Marc
authors.initials: M
authors.lastname: Bauwens
authors.forename: Anne
authors.initials: A
authors.lastname: Sechet
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Preud'Homme
authors.forename: Guy
authors.initials: G
authors.lastname: Touchard
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000032:analysis; D000970:Antineoplastic Agents / Q000008:administration & dosage; D001706:Biopsy; D005260:Female; D005921:Glomerulonephritis / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology*; D006510:Hepatitis B Antibodies / Q000032:analysis; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D008297:Male; D008870:Microtubules / Q000473:pathology* / Q000648:ultrastructure; D008875:Middle Aged; D010265:Paraproteinemias / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology*; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D000974:Antibodies, Antinuclear; D000970:Antineoplastic Agents; D006510:Hepatitis B Antibodies; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents