Intestinal protein expression profile identifies inflammatory bowel disease and predicts relapse.

To date, most studies have applied individual factors as indicators of disease classification and prognosis. The aim of this study is to determine whether clustering analysis of protein expression profiles in intestinal epithelia improves classification and prognosis in patients with inflammatory bowel disease (IBD). One hundred and twenty Crohn's disease (CD) patients, 117 ulcerative colitis (UC) patients and 120 cases of nonspecific colitis provided intestinal biopsy samples for tissue microarray (TMA). Both unsupervised and supervised analyses were used for evaluation of clustering and association with relapse. There was a significant concordance between cluster groups based on immunostaining data of TMA and clinical classification in distinguishing IBD from nonspecific colitis (kappa= 0.498, p<0.001). CD27, CD70, CD40, TRAF3, TRAF4 and TRAF2 presented similar immunostaining features, which were different from clusters of CD154, CD80 and TRAF5. Moreover, higher expression of TRAF2 was a predictor of relapse in patients with UC (p=0.006).Thus, protein expression profiles can distinguish IBD and nonspecific colitis, and combination analysis protein expression profiles show that TRAF2 can predict relapse of UC.