Risk factors for mucosal cytomegalovirus infection and specific endoscopic features in patients with ulcerative colitis.

Background: The role of cytomegalovirus (CMV) in ulcerative colitis (UC) remains controversial. This study aimed to evaluate the association between mucosal CMV load and disease severity and to identify predictive risk factors for CMV infection in active UC.

Methods: Mucosal CMV DNA load was quantified by real-time PCR in 231 patients with active UC. Disease activity was assessed using the Truelove & Witts clinical score, Mayo endoscopic subscore, and a modified Geboes score for histologic evaluation. Multivariate logistic regression was used to identify independent risk factors.

Results: CMV was detected in the colonic mucosa of 91 patients (39.4%). Patients with CMV infection showed significantly higher clinical (p < 0.001) and endoscopic severity (p = 0.002). The prevalence of CMV infection showed a positive trend with higher clinical disease activity (p < 0.001) and was also associated with more severe endoscopic (p = 0.002) and histologic inflammation (p = 0.004). Mucosal CMV load strongly correlated with clinical severity (ρ = 0.498, p < 0.001) and histologic grade (ρ = 0.735, p < 0.001). ROC analysis indicated that CMV load effectively predicted severe clinical (AUC = 0.796), endoscopic (AUC = 0.697), and histologic disease (AUC = 0.905; all p < 0.01). Multivariate analysis identified cobblestone-like appearance, punched-out ulcers, spontaneous bleeding, and decreased absolute lymphocyte count as independent predictors of CMV infection.

Conclusion: Mucosal CMV load is closely associated with inflammatory severity in UC. Characteristic endoscopic features and lymphopenia may serve as valuable predictors for CMV infection.