title: Anti-neutrophil cytoplasmic antibodies in rheumatoid arthritis: two case reports and review of literature.
abstract: BACKGROUND
  Anti-neutrophil cytoplasmic antibodies are typically detected in anti-neutrophil cytoplasmic antibody associated vasculitis, but are also present in a number of chronic inflammatory non-vasculitic conditions like rheumatoid arthritis. Rare cases of granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis, a vasculitic disorder frequently associated with the presence of anti-neutrophil cytoplasmic antibodies) in patients with rheumatoid arthritis have been described in literature.
  
  
  METHODS
  We report two middle-aged female patients with rheumatoid arthritis who developed anti-neutrophil cytoplasmic antibodies and symptoms reminiscent of granulomatosis with polyangiitis. Despite the lack of antibodies specific for proteinase 3 and the absence of a classical histology, we report a probable case of granulomatosis with polyangiitis in the first patient, and consider rheumatoid vasculitis in the second patient.
  
  
  CONCLUSIONS
  Taken together with previous reports, these cases highlight that anti-neutrophil cytoplasmic antibodies have to be evaluated very carefully in patients with rheumatoid arthritis. In this context, anti-neutrophil cytoplasmic antibodies detected by indirect immunofluorescence appear to have a low diagnostic value for granulomatosis with polyangiitis. Instead they may have prognostic value for assessing the course of rheumatoid arthritis.
authors.affiliation: Unité d'Immuno-Rhumatologie, Hôpital Lapeyronie, 191 avenue du doyen, Gaston Giraud Montpellier, 34295, France. dspoerl@postmail.ch.
authors.forename: David
authors.initials: D
authors.lastname: Spoerl
authors.forename: Yves-Marie
authors.initials: YM
authors.lastname: Pers
authors.forename: Christian
authors.initials: C
authors.lastname: Jorgensen