The significance of ANCA positivity in patients with inflammatory bowel disease

Abstract

Traditionally anti-neutrophil cytoplasmic antibodies(ANCA) are used to subtype patients with inflammatorybowel disease (IBD) and to predict primary sclerosingcholangitis (PSC). The clinical utility of this testing in theAustralian context is not known. Our retrospective, cross-sectional study looked at the results of ANCA testingperformed during routine clinical review and aimed toretrospectively review (1) the distribution of differentANCA subtypes for IBD patients, (2) the temporal changeof ANCA status, and (3) the predictive value of ANCAfor PSC. Sixty-four IBD patients attending our hospitalgastroenterology clinic between 2012 and 2016 had atleast one ANCA test requested. Surprisingly, >80% of theIBD patients in our cohort who underwent ANCA testinghad a positive ANCA result and a significant proportionhad positive PR3 antibodies. However, no specific ANCApatternpredictedaspecific IBD subtype or clinicalcourse. Pairing ANCA and anti-Saccharomyces cerevi-siae(ASCA) did not add value in subtyping IBD for thesepatients. Our study suggests that there is little value inordering an ANCA for patients with IBD. Show more