title: A case of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)-associated glomerulonephritis and concurrent membranous nephropathy.
abstract: BACKGROUND
  Myeloperoxidase anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (MPO-ANCA-GN) and concurrent membranous nephropathy (MN) are very rare combination. Their causal relationship has been suggested, but not determined.
  
  
  METHODS
  A 73-years-old male with 5-year history of proteinuria underwent an operation for his sigmoid colon cancer. Seven months later, he was referred to a nephrology division due to an exacerbating renal function and hypoalbuminemia. Laboratory examination revealed positive MPO-ANCA in the serum. A renal biopsy revealed a necrotizing extracapillary proliferative glomerulonephritis with crescents, demonstrating MPO-ANCA-GN. Whereas, immunofluorescent staining documented granular deposition of immumoglobulin (Ig) G and C3 along the capillary wall and electron microscopy showed subepithelial deposits in the glomerular basement membrane demonstrating MN. Immunofluorescent staining of IgG subclass showed positive IgG1, IgG2, negative IgG3 and weak positive IgG4 suggested the possibility of malignancy-associated MN.
  
  
  CONCLUSIONS
  Combination of MPO-ANCA-GN and MN are rare. Although the causal relationship has been suggested in some cases, we should consider all the possibilities including idiopathic MN and secondary MN associated with malignancy, drug use or infection.
authors.affiliation: Graduate School of Medicine, Division of Cardiology, Respiratory Medicine and Nephrology, Hirosaki University, 5 Zaifu-cho, Hirosaki, 036-8562, Japan. mshimada@cc.hirosaki-u.ac.jp
authors.forename: Michiko
authors.initials: M
authors.lastname: Shimada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Norio
authors.initials: N
authors.lastname: Nakamura
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Narita
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shimaya
authors.forename: Reiichi
authors.initials: R
authors.lastname: Murakami
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Osawa
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
mesh_terms: D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis*; D005921:Glomerulonephritis / Q000150:complications / Q000175:diagnosis*; D015433:Glomerulonephritis, Membranous / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008297:Male; D009195:Peroxidase / Q000032:analysis*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D009195:Peroxidase
references.citation: Nephrol Dial Transplant. 1997 May;12(5):1017-27
references.pmid: 9175062
references.citation: Intern Med. 1997 Nov;36(11):841-6
references.pmid: 9392363
references.citation: Nephrol Dial Transplant. 1993;8(8):696-702
references.pmid: 8414154
references.citation: Hum Pathol. 2011 May;42(5):649-58
references.pmid: 21292302
references.citation: Kidney Int. 2004 Jun;65(6):2145-52
references.pmid: 15149327
references.citation: Intern Med. 2005 Aug;44(8):853-8
references.pmid: 16157986
references.citation: Clin Nephrol. 2001 Nov;56(5):394-7
references.pmid: 11758012
references.citation: Nephrol Dial Transplant. 2004 Mar;19(3):574-9
references.pmid: 14767011
references.citation: N Engl J Med. 2009 Jul 2;361(1):11-21
references.pmid: 19571279
references.citation: Clin J Am Soc Nephrol. 2009 Feb;4(2):299-308
references.pmid: 19158367