P147 Usefulness of fecal S100A12 in defining mucosal healing in Ulcerative Colitis
T. Kobayashi*, O. Takeuchi, S. Kuronuma, M. Nakano, S. Umeda, H. Serizawa, N. Watanabe, T. Hibi
Kitasato University Kitasato Institute Hospital, Center for Advanced IBD Research and Treatment, Tokyo, Japan
Mucosal healing (MH) has been proposed as a therapeutic goal of ulcerative colitis (UC). However, it is still not feasible to perform "invasive" colonoscopy repeatedly to evaluate endoscopic changes and/or MH, therefore, usefulness of non-invasive biomarker has been widely investigated. Fecal S100A12 is reported to be more accurate in distinguishing IBD from non-IBD than fecal calprotectin (Gut 2007), and also believed to correlate with disease activity in UC, however, its clinical applicability in predicting MH is yet to be confirmed.
Written informed consent was obtained to measure fecal S100A12 from 45 patients with ulcerative colitis who had colonoscopy between November 2013 and June 2014. Mayo score was recorded when the stool sample was collected. Fecal S100A12 was measured by enzyme-linked immunosorbent assay.
Mayo endoscopic subscores (eMayo) were 0/1/2/3 in 9/12/12/12 patients, respectively. eMayo 0 and 1 are defined as MH. Fecal S100A12 was significantly lower in MH (n=21) compared to non-MH patients (n=24) (p<0.0001). Fecal S100A12 was significantly correlated with eMayo (r=0.748), Mayo rectal bleeding subscore (r=0.8068) and partial Mayo score (r=0.8101) (all p<0.0001). Correlation of eMayo with fecal S100A12 was superior compared to that with serum C-reactive protein (r=0.59). Fecal S100A12 very well distinguished MH from non-MH (ROC=0.94, sensitivity 87.5%, specificity 85.71% (cutoff 0.8956 mg/kg)), suggesting its usefulness in evaluating MH. There were 6 patients whose fecal S100A12 positivity did not correlate with MH status - all 3 patients in MH with positive S100A12 had extensive mild colitis (eMayo 1), and 3 patients in non-MH with negative fecal S100A12 had moderately active lesion (eMayo 2) limited to distal colon (<20 cm in length).
Our data suggest that fecal S100A12 well correlates with endoscopic and clinical severity and is useful in defining MH. Furthermore, fecal S100A12 seems to be able to quantitate the inflammation in the entire colon whereas eMayo is defined only by the severity of the most affected area. Therefore, fecal S100A12 could be not only alternative to, but could also be complementary to colonoscopy in assessing disease activity and defining MH in UC.