The Impact of Cytomegalovirus Detection in Colonic Tissue via PCR on Disease Severity and Endoscopic Activity in Ulcerative Colitis: A Single-Center Retrospective Cohort Study

Aim: Cytomegalovirus (CMV) infection is prevalent in patients with ulcerative colitis (UC), particularly in severe, steroid-refractory cases, yet its role in disease exacerbation remains debated. This retrospective cohort study included 110 patients with moderate-to-severe UC (as per Truelove and Witts criteria) who underwent colonoscopy and CMV testing. The primary objective was to investigate the correlation between tissue CMV DNA positivity, quantified via PCR, and endoscopic activity scores (Mayo and Rachmilewitz), alongside associations with inflammatory markers and recent steroid use. Materials and Methods: A retrospective cohort study included 110 UC patients from a university clinic (January 2021–April 2024). Patients underwent colonoscopy with tissue and blood PCR for CMV detection. Endoscopic activity was assessed using Mayo and Rachmilewitz scores. Results: Our results showed that 37% of patients were tissue CMV-DNA over 250 copies, with significantly higher Mayo scores (8.7 vs. 7.6, p=0.02), Rachmilewitz scores (8.6 vs. 7.4, p=0.03), erythrocyte sedimentation rates (54.3 vs. 42.8, p=0.04), and serum CMV levels (878.9 vs. 71.4, p=0.008). Correlation analysis revealed positive associations between tissue CMV copy number and sedimentation rates (r=0.22, p=0.01), serum CMV (r=0.37, p=0.0001), Mayo scores (r=0.18, p=0.05), and Rachmilewitz scores (r=0.25, p=0.008). Logistic regression analysis indicated a 12-fold increased risk of CMV positivity with recent steroid use (p=0.030). Conclusion: This study directly examines tissue CMV-DNA positivity and endoscopic activity degrees. Our findings suggest that the presence of CMV in colonic tissue may increase the endoscopic activity score in moderate to severe ulcerative colitis. These results underscore the need for routine CMV screening and larger prospective studies to clarify this interaction.