Histologic markers of inflammation in patients with ulcerative colitis in clinical remission

Mucosal healing, based on histologic analysis, is an end point of maintenance therapy for patients with ulcerative colitis (UC). There are few data on how histologic signs of inflammation correlate with endoscopic and peripheral blood measures of inflammation in these patients. We investigated patterns of histologic features of inflammation in patients with UC in clinical remission, and correlated these with endoscopic and biochemical measures of inflammation.

We performed a prospective observational study of 103 patients with UC in clinical remission undergoing surveillance colonoscopy while receiving maintenance therapy with mesalamine or thiopurines; 2674 biopsy specimens were collected from 708 colonic segments. Each colonic segment was evaluated based on the Mayo endoscopic subscore and the Geboes histology score (range, 0-5.4). Biomarkers were measured in peripheral blood samples.

Histologic features of inflammation were found in 54% of patients receiving maintenance therapy; 37% had at least moderate inflammation based on histology scores. Of the 52 patients with endoscopic evidence only of left-sided colitis, 34% had histologic features of inflammation in their proximal colon. Histology scores correlated with endoscopic scores for per-segment inflammation (Spearman ρ = 0.65; P < .001). Patients with histology scores greater than 3.1 had a significantly higher mean level of C-reactive protein than those with scores less than 3.1. There were no differences among treatment groups in percentages of patients with histologic scores greater than 3.1.

Patients in clinical remission from UC still frequently have histologic features of inflammation, which correlate with endoscopic appearance. Patients with at least moderate levels of inflammation, based on histologic grading (score >3.1), have higher serum levels of C-reactive protein, which could be used as a surrogate marker of histologic inflammation.