Detection of a novel antigen for Crohn's disease.

ABSTRACT

BACKGROUND AND AIMS: Accurate serological assays are desirable for the diagnosis of inflammatory bowel disease (IBD). We identify an antigen-like substance called Crohn's disease (CD) antibody binding polypeptide (CABP). As a serological marker, anti-CABP may contribute to the diagnosis of IBD. The present study aims to evaluate the clinical role of anti-CABP as a serological antibody for IBD. METHODS: Using enzyme-linked immunosorbent assay (ELISA), serum anti-CABP, anti-Saccharomyces cerevisiae antibody (ASCA) and perinuclear anti-neutrophil cytoplasmic antibody (pANCA), titers were tested in 168 CD patients, 123 ulcerative colitis (UC) patients and 170 controls. The correlation between serum antibody and clinical characteristics was investigated. The diagnostic potential of the anti-CABP was evaluated by receiver operating characteristic (ROC) analysis. RESULTS: The titers of anti-CABP (IgA or IgG) and ASCA IgG of CD patients were significantly higher than non-CD group (all p < .01). In the differential diagnosis of CD and non-CD, anti-CABP IgA revealed an area under the curve (AUC) of 0.706 and anti-CABP IgG demonstrated an AUC of 0.788. As an individual antibody, anti-CABP could effectively distinguish CD from non-CD (AUC 0.816), and the diagnostic efficacy was better than that of ASCA (AUC 0.680). The combined use of anti-CABP, ASCA and pANCA significantly improved the diagnostic value (AUC 0.857). Anti-CABP positive rates were associated with perianal lesions and disease location in CD patients (both p < .05). CONCLUSIONS: Our results suggested that anti-CABP could be used as a serological marker to assist the diagnosis of CD. CLINICAL TRIAL REGISTRATION This trial is registered with clinical trial registration unique identifier ChiCTR2000037094.