Genomic profiling of intestinal T-cell receptor repertoires in inflammatory bowel disease.

Growing evidence shows that inflammatory bowel disease (IBD) results from dysregulation of immune responses to gut microbes. T-cell receptors (TCRs) expressed on the T-cell surface play critical roles in discriminating pathogens from commensal intestinal microorganisms at the front line of the adaptive immune system. The breakdown of this interaction may trigger persistent inflammatory responses to gut bacteria, resulting in IBD. Taking advantage of high-throughput sequencing, we developed an integrated approach to dissect the intestinal TCR repertoires underlying IBD by collecting peripheral blood and inflamed intestine from the same set of 11 IBD cases. The intestinal TCR repertoires show lower clonotype diversity (p < 0.05) and stronger clonal expansion (p < 0.02) than those in the blood. This pattern becomes more profound in TCRs unique to the inflamed tissue compared with shared TCRs. Our approach further identified the increased usage of TRAV12-3 (false discovery rate, FDR < 5%), which biases its choices of J genes towards the reduction of TRAJ37 and TRAJ43 usage (FDR < 20%) in the inflamed intestine. Our genomic profiling suggests that this selective bias of V and J gene usage may lead to a loss of diversity in the intestinal TCR repertoires and result in mucosal inflammation in IBD.

Colon capsule endoscopy is a viable alternative to colonoscopy for the investigation of intermediate- and low-risk patients with gastrointestinal symptoms: results of a pilot study.

Background and study aims Colon capsule endoscopy (CCE) is a recommended viable alternative to colonoscopy for colonic visualisation in a variety of clinical settings with proven efficacy in polyp detection, surveillance, screening and Inflammatory Bowel Disease (IBD) assessment. CCE efficacy in an unselected average risk symptomatic cohort has yet to be established. The aim of this study was to determine the feasibility of CCE imaging assessment in average risk symptomatic patients as an alternative to colonoscopy with and without additional biomarker assessment. Patients and methods This was a prospective, single-center comparison study of colonoscopy, CCE and biomarker assessment. Results Of 77 invited subjects, 66 underwent both a CCE and colonoscopy. A fecal immunochemical test (FIT) and fecal calprotectin (FC) were available in 56 and 59 subjects. In all 64 % (n = 42) had any positive finding with 16 (24 %) found to have significant disease (high-risk adenomas, IBD) on colonoscopy. The CCE completion rate was 76 %, five (8 %) had an inadequate preparation, the CCE polyp detection rate was high at 35 %. The sensitivity, specificity, positive and negative predictive values of CCE for significant disease were 81 %, 98 %, 93 % and 94 % respectively. In addition, three (5 %) significant small bowel diagnoses were made on CCE. FC and FIT were frequently elevated in patients with both colitis (5/7, 71 %) and high-risk adenomas (4/7 57 %). While both had a low positive predictive value for clinically significant disease, FIT 32 % and FC 26 %. Conclusions CCE is a safe and effective alternative to colonoscopy in symptomatic average risk patients with or without the addition of biomarker screening.