Aim: Anti-neutrophil cytoplasmic antibodies (ANCAs) detected by indirect immunofluorescence have been found in patients with inflammatory bowel disease (IBD). Nevertheless, specific antibodies against proteinase-3 (PR3) are rare in this context.
Methods: Sera from 30 consecutive pediatric patients with IBD were evaluated for ANCA-indirect immunofluorescence and its specific antibodies to investigate whether PR3-ANCA positivity (PR3-ANCA+) identifies a distinct IBD subtype.
Results: The 5 PR3-ANCA+ patients (17%) showed significantly more concomitant biliary disease and severe anal blood loss (P < 0.05). None had vasculitis features at diagnosis nor during follow-up.
Conclusions: This pilot study demonstrates significant clinical differences between the PR3-ANCA–positive and –negative IBD subset.