title: Apoptosis, proliferation and inflammatory infiltration in ANCA-positive glomerulonephritis.
abstract: OBJECTIVE
  Antineutrophil cytoplasmic antibodies (ANCA) are detected in most patients with crescentic glomerulonephritis and necrotizing small vessel vasculitis. ANCA cause renal inflammation and proliferation. Apoptosis is necessary for resolution of inflammation. We studied apoptosis, apoptosis-regulating proteins, proliferation and infiltration with ANCA target antigen containing neutrophils and monocytes in renal biopsies from ANCA patients and disease controls.
  
  
  METHODS
  Skin biopsies from patients with leukocytoclastic vasculitis (n=6) and renal biopsies from patients with ANCA vasculitis (n=10), ANCA-negative crescentic glomerulonephritis (CGN, n=7), mesangio-proliferative GN (n=6), post-streptococcal GN (PSGN, n=4), diabetic nephropathy (n=6) and minimal change nephropathy (MCNP, n=6) were evaluated by immunohistochemistry. Biopsies were stained for apoptosis (TdT-mediated UTP nick-end labeling, TUNEL), proliferation (Ki-67), neutrophils (NP 57), and monocytes (KP 1). We also evaluated Fas and Bcl-2 expression.
  
  
  RESULTS
  Apoptosis was common in leukocytoclastic vasculitis skin biopsies, but was rare in renal biopsies. ANCA-positive NCGN showed the lowest apoptosis rate, similar to MCNP and diabetic nephropathy. The highest apoptosis rate was seen in PSGN. The highest glomerular Bcl-2 expression was present in ANCA-positive biopsies. The Bcl-2/TUNEL ratio was significantly increased in ANCA-positive necrotizing crescentic glomerulonephritis (NCGN) compared to ANCA-negative CGN and PSGN. When proliferation (Ki-67) and apoptosis were expressed as a ratio, we observed the highest index in biopsies from patients with ANCA-positive NCGN because of their low apoptosis rates. Finally, the glomerular inflammatory infiltrate in ANCA-positive NCGN showed a high percentage of neutrophils.
  
  
  CONCLUSIONS
  These preliminary results suggest an imbalance between apoptosis and proliferation, favoring proliferation, in renal biopsies from ANCA-positive NCGN patients.
authors.affiliation: HELIOS-Klinikum Berlin, Franz Volhard Clinic, Germany. kettritz@fvk-berlin.de
authors.forename: R
authors.initials: R
authors.lastname: Kettritz
authors.forename: S
authors.initials: S
authors.lastname: Wilke
authors.forename: S
authors.initials: S
authors.lastname: von Vietinghoff
authors.forename: F
authors.initials: F
authors.lastname: Luft
authors.forename: W
authors.initials: W
authors.lastname: Schneider
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000378:metabolism*; D017209:Apoptosis; D049109:Cell Proliferation; D003928:Diabetic Nephropathies / Q000276:immunology / Q000473:pathology; D005260:Female; D005921:Glomerulonephritis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology / Q000473:pathology; D006801:Humans; D008297:Male; D009000:Monocytes / Q000473:pathology; D009402:Nephrosis, Lipoid / Q000276:immunology / Q000473:pathology; D009504:Neutrophils / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014657:Vasculitis / Q000276:immunology / Q000473:pathology; D019014:fas Receptor / Q000378:metabolism
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor