title: Prevalence and clinical significance of antineutrophil cytoplasmic antibodies in Churg-Strauss syndrome.
abstract: OBJECTIVE
  Churg-Strauss syndrome (CSS) is classified among the so-called antineutrophil cytoplasmic antibody-associated systemic vasculitides (AASVs) because of its clinicopathologic features that overlap with the other AASVs. However, while antineutrophil cytoplasmic antibodies (ANCAs) are consistently found in 75-95% of patients with Wegener's granulomatosis or microscopic polyangiitis, their prevalence in CSS varies widely and their clinical significance remains uncertain. We undertook this study to examine the prevalence and antigen specificity of ANCAs in a large cohort of patients with CSS. Moreover, we evaluated the relationship between ANCA positivity and clinicopathologic features.
  
  
  METHODS
  Immunofluorescence and enzyme-linked immunosorbent assay were used to determine the presence or absence of ANCAs in 93 consecutive patients at the time of diagnosis. The main clinical and pathologic data, obtained by retrospective analysis, were correlated with ANCA status.
  
  
  RESULTS
  ANCAs were present by immunofluorescence in 35 of 93 patients (37.6%). A perinuclear ANCA (pANCA) pattern was found in 26 of 35 patients (74.3%), with specificity for myeloperoxidase (MPO) in 24 patients, while a cytoplasmic ANCA pattern, with specificity for proteinase 3, was found in 3 of 35 patients (8.6%). Atypical patterns were found in 6 of 30 patients with anti-MPO antibodies (20.0%). ANCA positivity was associated with higher prevalences of renal disease (51.4% versus 12.1%; P < 0.001) and pulmonary hemorrhage (20.0% versus 0.0%; P = 0.001) and, to a lesser extent, with other organ system manifestations (purpura and mononeuritis multiplex), but with lower frequencies of lung disease (34.3% versus 60.3%; P = 0.019) and heart disease (5.7% versus 22.4%; P = 0.042).
  
  
  CONCLUSIONS
  ANCAs are present in approximately 40% of patients with CSS. A pANCA pattern with specificity for MPO is found in most ANCA-positive patients. ANCA positivity is mainly associated with glomerular and alveolar capillaritis.
authors.affiliation: Dipartimento di Nefrologia e Immunologia, Azienda Ospedaliera Ospedale San Carlo Borromeo, Milan, Italy. renato.sinico@oscb.sined.net
authors.forename: Renato A
authors.initials: RA
authors.lastname: Sinico
authors.forename: Lucafrancesco
authors.initials: L
authors.lastname: Di Toma
authors.forename: Umberto
authors.initials: U
authors.lastname: Maggiore
authors.forename: Paolo
authors.initials: P
authors.lastname: Bottero
authors.forename: Antonella
authors.initials: A
authors.lastname: Radice
authors.forename: Cinzia
authors.initials: C
authors.lastname: Tosoni
authors.forename: Chiara
authors.initials: C
authors.lastname: Grasselli
authors.forename: Laura
authors.initials: L
authors.lastname: Pavone
authors.forename: Gina
authors.initials: G
authors.lastname: Gregorini
authors.forename: Stefano
authors.initials: S
authors.lastname: Monti
authors.forename: Micol
authors.initials: M
authors.lastname: Frassi
authors.forename: Filomena
authors.initials: F
authors.lastname: Vecchio
authors.forename: Caterina
authors.initials: C
authors.lastname: Corace
authors.forename: Emanuela
authors.initials: E
authors.lastname: Venegoni
authors.forename: Carlo
authors.initials: C
authors.lastname: Buzio
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis*; D000918:Antibody Specificity / Q000276:immunology*; D002467:Cell Nucleus / Q000276:immunology / Q000473:pathology; D015267:Churg-Strauss Syndrome / Q000150:complications / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D005938:Glucocorticoids / Q000627:therapeutic use; D006470:Hemorrhage / Q000209:etiology / Q000473:pathology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007674:Kidney Diseases / Q000209:etiology / Q000473:pathology; D008171:Lung Diseases / Q000209:etiology / Q000473:pathology; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D012189:Retrospective Studies
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D009195:Peroxidase