title: ANCA-associated crescentic glomerulonephritis with immune complex deposits.
abstract: BACKGROUND
  Several authors have reported cases of anti-neutrophil cytoplasmic antibody (ANCA)-associated crescentic glomerulonephritis (CGN) with definite immune complex (IC) deposits, however, the clinical and pathological significance of IC deposits in patients with ANCA-associated CGN remains unclear.
  
  
  METHODS
  Renal biopsy specimens from 28 patients with a diagnosis of CGN and positivity for anti-myeloperoxidase (MPO)-ANCA were retrospectively evaluated. Clinical data were compared between patients with IC deposits (Group A) and patients without IC deposits (Group B).
  
  
  RESULTS
  In 12 patients (43%; Group A), IC deposits were detected in the mesangium and/or along the glomerular capillary walls, while typical pauci-immune CGN without IC deposits was found in 16 patients (57%; Group B). Compared with Group B, Group A had lower levels of MPO-ANCA (171 ± 156 vs. 352 ± 299 EU) and C-reactive protein (CRP) (0.63 ± 1.04 vs. 4.45 ± 4.00 mg/dl), as well as less pulmonary involvement (8.3% vs. 56.3%) at diagnosis. However, Group A had significantly heavier proteinuria (2.46 ± 1.67 vs. 0.76 ± 0.52 g/d). Group A was classified into three subgroups: Group A1 with mesangial IgA and C3 deposits, A2 with mesangial IgG and C3 deposits, and A3 with IgG and C3 deposits mainly in the capillary walls.
  
  
  CONCLUSIONS
  ANCA-associated CGN causes two types of renal involvement, which are the pauci-immune type without IC deposits and the IC deposition type that involves three patterns of IC deposition in the glomeruli. The reason why IC deposits are associated with renal-limited vasculitis and not systemic vasculitis remains unclear.
authors.affiliation: Department of Pathology, Toranomon Hospital, Tokyo, Japan. k-sumida@toranomon.gr.jp
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sumida
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ubara
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Nomura
authors.forename: Junichi
authors.initials: J
authors.lastname: Hoshino
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Suwabe
authors.forename: Rikako
authors.initials: R
authors.lastname: Hiramatsu
authors.forename: Eiko
authors.initials: E
authors.lastname: Hasegawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Hayami
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamanouchi
authors.forename: Naoki
authors.initials: N
authors.lastname: Sawa
authors.forename: Fumi
authors.initials: F
authors.lastname: Takemoto
authors.forename: Kenmei
authors.initials: K
authors.lastname: Takaichi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ohashi
mesh_terms: D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000276:immunology* / Q000473:pathology; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis*; D000936:Antigen-Antibody Complex / Q000032:analysis*; D001706:Biopsy; D002097:C-Reactive Protein / Q000032:analysis; D002196:Capillaries / Q000276:immunology; D005260:Female; D005921:Glomerulonephritis / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007564:Japan; D007668:Kidney / Q000098:blood supply / Q000276:immunology* / Q000648:ultrastructure; D008297:Male; D050527:Mesangial Cells / Q000276:immunology; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009195:Peroxidase / Q000032:analysis; D012189:Retrospective Studies
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000936:Antigen-Antibody Complex; D002097:C-Reactive Protein; D009195:Peroxidase