Claudin-2 simplifies histological assessment of activity/remission of ulcerative colitis in real-life daily practice

Objectives Mucosal healing, and in particular histological mucosal healing, represents the new frontier as a treatment goal for inflammatory bowel diseases. However, the assessment of mucosal healing is presently somewhat limited by the numerous pathological scores available, and the lack of a global consensus on how to best assess it. For this reason, the availability of a simple and rapid test to evaluate the inflammatory state of the mucosa after treatment would be useful, especially for the daily routine. Methods To exploit the above purpose, we evaluated the possible usefulness of antibodies against claudin-2, a protein of intestinal epithelium tight junctions, as a possible test to assess the presence of activity in ulcerative colitis following treatment. Biopsies from 28 patients with distal localization of the disease and clinical and endoscopic remission were tested for claudin-2 reactivity. Results Claudin-2 reactivity was always negative in noninvolved segments and displayed a variable staining intensity in concordance with the histological activity. There was a highly significant (P < 0.0001) correlation between histological score and claudin-2 expression in the colonic segments involved (descending, sigmoid colon, and rectum). Conclusions Our results suggest that the use of claudin-2 in the routine daily practice could simplify and corroborate the results of current histological evaluations, especially in clinical practice and posttreatment follow-up.