Possible diagnostic role of antibodies to Crohn's disease peptide (ACP): results of a multicenter study in a Japanese cohort

Various noninvasive tests have been studied to screen for patients with Crohn's disease (CD), and were found to have limited accuracy and sensitivity, particularly in Asian populations. The aim of our study was to explore the possible diagnostic utility of antibodies to the CD peptide (ACP) in patients with CD. In a multicenter study using enzyme-linked immunosorbent assay, serum ACP levels were determined in 196 patients with CD, 210 with ulcerative colitis, 98 with other intestinal diseases, 132 with other inflammatory diseases, and 183 healthy controls. and then examined for correlation to clinical variables. The diagnostic utility of ACP was evaluated by receiver operating characteristics analysis and compared with anti-Saccharomyces cerevisiae antibodies (ASCA). ACP levels were significantly elevated in the CD patients, but not in the other groups that included UC, other intestinal diseases, other inflammatory diseases and the healthy controls. Among these other groups, ACP levels were not significantly different. In the CD patients, ACP had a higher sensitivity and specificity (63.3 and 91.0 %, respectively) than ASCA (47.4 and 90.4 %). ACP levels were negatively associated with disease duration, but not with CDAI, disease location, or medical treatment. ACP, a newly proposed serologic marker, was significantly associated with CD and was highly diagnostic. Further investigation is needed across multiple populations of patients and ethnic groups, and more importantly, in prospective studies.