title: Value of non-identified ANCA (non-PR3, non-MPO) in the diagnosis of granulomatosis with polyangiitis (Wegener's granulomatosis).
abstract: OBJECTIVE
  Determine the frequency of granulomatosis with polyangiitis (GPA) associated with non-identified ANCA (non-MPO, non-PR3 ANCA) and secondarily compare their clinic with GPA associated with MPO-positive or PR3-positive ANCA.
  
  
  METHODS
  In a monocentric retrospective observational study, clinical data of 398 patients with non-identified ANCA (titer of ANCA at least 1/80 by immunofluorescence on ethanol fixed PMN) was gathered over a period of 6 years. GPA patients from this population were compared with GPA patients with identified ANCA on the basis of clinical, biological, immunological and histological features.
  
  
  RESULTS
  The most common diseases associated with non-identified ANCA were inflammatory bowel diseases accounting for 17% of diseases. GPA accounted for only 1.8% of cases. There were no significant differences in terms of clinical and histological characteristics between GPA with non-identified ANCA and GPA with identified ANCA, but significantly higher CRP levels were observed in GPA patients with identified ANCA (p = 0.005). Localized disease (ear, nose and throat and/or lung involvement without any other systemic involvement) was more frequent in the group of GPA with nonidentified ANCA (p = 0.047) as compared to GPA with identified ANCA. This explains that the former group of patients was less frequently treated by cyclophosphamide than the latter (p = 0.016).
  
  
  CONCLUSIONS
  GPA with non-MPO, non-PR3 ANCAs is relatively rare. Our study suggests that GPA with nonidentified ANCA differs from GPA with identified ANCA by the frequency of localized forms.
authors.affiliation: a Department of Rheumatology , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Givaudan
authors.affiliation: b Department of Internal Medicine , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Vandergheynst
authors.affiliation: c Department of Immunobiology Clinic , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Stordeur
authors.affiliation: c Department of Immunobiology Clinic , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Annick
authors.initials: A
authors.lastname: Ocmant
authors.affiliation: d Department of Emergency , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Christian
authors.initials: C
authors.lastname: Melot
authors.affiliation: a Department of Rheumatology , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Valérie
authors.initials: V
authors.lastname: Gangji
authors.affiliation: a Department of Rheumatology , Hôpital Erasme, Université Libre de Bruxelles , Bruxelles , Belgium.
authors.forename: Muhammad S
authors.initials: MS
authors.lastname: Soyfoo
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic; D003937:Diagnosis, Differential; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic
keywords: ANCA; autoimmune; diagnosis; granulomatosis with polyangiitis; non-identified; vasculitis