title: Membranoproliferative glomerulonephritis secondary to monoclonal gammopathy.
abstract: OBJECTIVE
  Membranoproliferative glomerulonephritis (MPGN) is an immune complex-mediated glomerulonephritis characterized by subendothelial and mesangial deposition of immune complexes. Autoimmune diseases and chronic infections, such as hepatitis C, are commonly recognized causes of MPGN; however, monoclonal gammopathy is a less widely recognized cause of MPGN.
  
  
  METHODS
  We reviewed all renal biopsies of MPGN in Mayo Clinic patients during a 6-year period to determine the association of monoclonal gammopathy with MPGN. Results were correlated with electrophoresis studies and bone marrow biopsies to clarify the relationship between MPGN and gammopathies.
  
  
  RESULTS
  Of 126 patients with MPGN, 20 did not have workup for hepatitis B or C. Of the remaining 106 patients, 25 (23.5%) were positive for hepatitis B or C. Of the 81 hepatitis-negative patients, 13 were not evaluated for gammopathies. Of the remaining 68 patients, 28 (41.1%) had serum and/or urine electrophoresis studies positive for monoclonal gammopathy. Serum immunofixation electrophoresis was the most sensitive method for diagnosing monoclonal gammopathy. Renal biopsy showed a membranoproliferative pattern of injury; immunofluorescence microscopy was often instrumental in diagnosing the underlying gammopathy. On the basis of the bone marrow biopsy, monoclonal gammopathy of undetermined significance was the most common entity associated with MPGN. Other, less common causes included multiple myeloma, low-grade B cell lymphoma, and chronic lymphocytic leukemia.
  
  
  CONCLUSIONS
  Monoclonal gammopathy is an important and common cause of MPGN; therefore, all patients with a diagnosis of MPGN should be evaluated for an underlying monoclonal gammopathy.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA. sethi.sanjeev@mayo.edu
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Sethi
authors.forename: Ladan
authors.initials: L
authors.lastname: Zand
authors.forename: Nelson
authors.initials: N
authors.lastname: Leung
authors.forename: Richard J H
authors.initials: RJ
authors.lastname: Smith
authors.forename: Dragan
authors.initials: D
authors.lastname: Jevremonic
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Herrmann
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Fervenza
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000097:blood / Q000652:urine; D001706:Biopsy; D001797:Blood Protein Electrophoresis; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D001856:Bone Marrow Examination; D005260:Female; D005455:Fluorescent Antibody Technique; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D006801:Humans; D007668:Kidney / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010265:Paraproteinemias / Q000150:complications / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal