What is the significance in routine care of c-ANCA/PR3-ANCA in the absence of systemic vasculitis? A case series

CER3309
2008 Vol.26, N°3 ,Suppl.49
PI 0053, PF 0056
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PMID: 18799054 [PubMed]

Abstract

OBJECTIVES:
ANCA has come to play an important role in diagnosing vasculitis. In selected populations c-ANCA/PR3-ANCA has a high specificity and sensitivity for vasculitis. In clinical practice, how individuals with c-ANCA/PR3-ANCA but without sufficient evidence of systemic vasculitis should be managed is unclear. We therefore retrospectively assessed the disease panorama and outcome in a consecutive series of individuals with c-ANCA/PR3-ANCA, and studied in detail those individuals who turned out not to fulfil criteria for vasculitic disease.
METHODS:
The study population consisted of 74 consecutive patients who all had a positive test for C-ANCA and PR3-ANCA between 1992 and 2002 at the Immunology laboratory at Uppsala University Hospital, Sweden. The patients` medical files were reviewed and their diagnosis re-evaluated through June 2006.
RESULTS:
18 of the 74 ANCA-positive individuals did not present clinical evidence supportive of, or insufficient to support, a diagnosis of systemic vasculitis, but presented a range of other diseases. During a mean follow-up of 6.8 years, none of these 18 patients developed vasculitis.
CONCLUSIONS:
Individuals with a positive c-ANCA and PR3-ANCA but no vasculitis at the time of testing run an unknown but likely small risk of later developing vasculitis. In this group, a positive ANCA may represent background noise (borderline titres) or be a marker of inflammatory activity rather than of vasculitic disease (high titres).