title: Is presence of ANCA in crescentic IgA nephropathy a coincidence or novel clinical entity? A case series.
abstract: BACKGROUND
  There are few anecdotal reports of circulating antineutrophil cytoplasmic autoantibodies (ANCAs) in patients with immunoglobulin A (IgA) nephropathy.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  We studied 8 patients with crescentic IgA nephropathy associated with ANCAs against myeloperoxidase (n = 5) and proteinase 3 (n = 3) followed up for 2.4 +/- 1.7 years. They were compared with 26 patients with IgA nephropathy with > 10% crescentic glomeruli, but negative for ANCAs.
  
  
  RESULTS
  We analyzed clinical and histologic features of patients and their response to treatment.
  
  
  METHODS
  Screening for ANCAs was performed using indirect immunofluorescence, and positive results were verified using enzyme-linked immunosorbent assay.
  
  
  RESULTS
  All patients with crescentic IgA nephropathy and positive for ANCAs, compared with only one-third of ANCA-negative patients, presented with the clinical syndrome of rapid progressive glomerulonephritis. ANCA-positive patients reached a higher peak serum creatinine level within the first 3 months (4.2 +/- 2.2 vs 2.5 +/- 1.9 mg/dL; estimated glomerular filtration rate, 19.3 +/- 10.2 vs 45.9 +/- 30.1 mL/min/1.73 m(2)). ANCA-positive patients with IgA nephropathy had a higher percentage of crescentic glomeruli (54.3% +/- 18%) compared with ANCA-negative patients with crescentic IgA nephropathy (34.5% +/- 26%). ANCA-positive patients were treated using cyclophosphamide and corticosteroids. Kidney function improved in all these patients: serum creatinine level decreased from the peak of 4.2 +/- 2.2 to 1.7 +/- 0.7 mg/dL at the end of follow up (estimated glomerular filtration rate, 19.3 +/- 10.2 to 44.6 +/- 11.1 mL/min/1.73 m(2)). In contrast, no significant improvement was achieved in ANCA-negative patients.
  
  
  CONCLUSIONS
  Patients with IgA nephropathy, crescents, and positive for ANCAs represent a clinical entity with a diverse more exaggerated clinical and histologic picture. However, disease in these patients responded well to aggressive immunosuppressive therapy.
authors.affiliation: Department of Nephrology, Heinrich-Heine University of Düsseldorf, Germany.
authors.forename: Christos
authors.initials: C
authors.lastname: Bantis
authors.forename: Maria
authors.initials: M
authors.lastname: Stangou
authors.forename: Christoph
authors.initials: C
authors.lastname: Schlaugat
authors.forename: Efstathios
authors.initials: E
authors.lastname: Alexopoulos
authors.forename: Aphroditi
authors.initials: A
authors.lastname: Pantzaki
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Memmos
authors.forename: Katrin
authors.initials: K
authors.lastname: Ivens
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Heering
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D005260:Female; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000145:classification; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic