Pancolonic mast cell elevation correlates with IBS-like symptoms in ulcerative colitis patients achieving combined endoscopic and histologic remission: a retrospective case–control study

• IBS-like symptoms in ulcerative colitis patients following endoscopic and histologic remission correlate with elevated mucosal mast cells. • In these patients mast cell elevation occurs throughout the colon and is independent of the duration of remission. • Elevated mucosal mast cell density discriminates symptomatic from asymptomatic patients. • Mast cells may be a potential therapeutic target for symptom-directed therapy. Approximately 30% of patients with ulcerative colitis (UC) who achieve endoscopic and histologic remission after biologic therapy continue to report persistent irritable bowel syndrome (IBS)-like lower gastrointestinal symptoms. We hypothesized that mucosal mast cells, which have been implicated in IBS pathophysiology, might play a role. We conducted a retrospective case–control study using systematic random sampling of cases from an institutional database. UC patients with a Mayo endoscopic score of 0 and absent mucosal neutrophils were identified through a consecutive review of electronic medical records in chronological order. Symptom status was determined by contemporaneous clinical documentation within two weeks of colonoscopy. The first twelve symptomatic patients meeting all eligibility criteria were matched by age, sex, disease duration, and therapy to twelve asymptomatic controls. Ninety-six colonic biopsies were reviewed histologically and stained for CD117 to quantify mast cell density. Mucosal mast cell density was significantly higher in symptomatic patients compared with asymptomatic controls (54.9 ± 11.5 vs. 40.2 ± 13.2 cells per high-power field; P = 0.0007). It was observed consistently across colonic segments and was uncorrelated with duration of remission (range, 0–208 months). Receiver operating characteristic analysis demonstrated good discrimination between symptomatic and asymptomatic patients (AUC = 0.875). Pancolonic mucosal mast cell density is associated with persistent IBS-like symptoms in UC patients who achieved endoscopic and histologic remission, suggesting a durable potential target for IBS-like symptom-directed therapy.