Abstract Background Cytomegalovirus (CMV) colitis mimics acute IBD flares, making it a critical differential diagnosis in acute severe colitis (ACS). Therefore, it’s an important differential diagnosis in patients with ACS. Prevalence ranges from 10 to 30% in steroid-refractory ulcerative colitis (UC).1,2 Corticosteroids are identified as risk factors for CMV colitis. Evidence for biologics and small molecules remains conflicting or absent.1 This study aimed to evaluate demographic data of CMV colitis in a central European inflammatory bowel disease (IBD) cohort. Methods We conducted a retrospective analysis of 110 colon biopsy samples of IBD patients with clinical suspicion of CMV colitis at our IBD center between 2020 and 2024. All biopsies were obtained from the most inflamed colonic segments during diagnostic colonoscopy. CMV testing including immunohistochemistry (IHC) and quantitative tissue PCR (qPCR) was performed at the affiliated pathology and virology departments. CMV positivity was defined as IHC+/qPCR-, IHC-/qPCR+ or IHC+/qPCR+.3 Results A total of 110 IBD patients with clinical suspicion of CMV colitis were included. The median age was 43.5 years IQR 36-57. Gender distribution was nearly equal: 50.9% male (56/110) and 49.1% female (54/110). The majority had UC 75.5% (83/110), followed by Crohn’s colitis (CC) 23.6% (26/110), and colitis indeterminata (1/110). The overall prevalence of CMV colitis was 16.4% (18/110). Among CMV-positive cases 94.4% (17/18) had UC and 5.6% (1/18) had CC. Among the 18 CMV-positive patients, current immunosuppressive therapy included systemic glucocorticoids (GC) 33.3% (6/18), VDZ 27.8% (5/18), Updadacitinib (UPA) 22.2% (4/18), Ustekinumab (UST) 11.1% (2/18), Adalimumab (ADA) 5.6% (1/18), Filgotinib (FILGO) 5.6% (1/18), and topical GCs 5.6% (1/18). 94.4% (17/18) of CMV positive patients had a history of prior systemic immunosuppressive therapy. Of those, 6 never received a biologic, 5 received 1 biologic, 3 received 2 biologics, and 4 received ≥3 biologics. 61.1% (11/18) CMV-positive patients had a documented prior episode of CMV colitis. Conclusion The prevalence of CMV-colitis was 16.4% among IBD patients with clinical suspicion, predominantly affecting those with UC (94.4%). Nearly all positive cases had prior or current immunosuppressive exposure, mostly systemic GCs (33.3%), VDZ (27.8%) or JAK inhibitors (UPA/FILGO 27.8%). Notably, 61.1% had a documented prior episode of CMV colitis. These findings highlight, that immunosuppressed patients – particularly those with UC are at elevated risk of a CMV colitis. Further studies are needed to identify IBD patients and immunosuppressive therapies associated with the highest risk of CMV colitis. References: 1. Beswick L, Ye B, Van Langenberg DR. Toward an algorithm for the diagnosis and management of CMV in patients with colitis. Inflamm Bowel Dis.Lippincott Williams and Wilkins. 2016;22(12):2966-2976. doi:10.1097/MIB.0000000000000958 2. Soni K, Puing A. Cytomegalovirus Colitis in Adult Patients with Inflammatory Bowel Disease. Viruses.Multidisciplinary Digital Publishing Institute (MDPI). 2025;17(6). doi:10.3390/v17060752 3. Kucharzik T, Ellul P, Greuter T, et al. ECCO Guidelines on the Prevention, Diagnosis, and Management of Infections in Inflammatory Bowel Disease. J Crohns Colitis.Oxford University Press. 2021;15(6):879-913. doi:10.1093/ecco-jcc/jjab052 Conflict of interest: Müller, Antonia: I have received support from Dr. Falk Pharma and AMGEN in the form of travel, accommodation, and conference expenses, as well as remuneration for a lecture at Biologica Circle South in 2025. I have no further conflicts of interest to declare. Strasser, Florian: Travel support and speaker honoraria from Abbvie. Travel support from Johnson & Johnson. No other conflicts of interest are declared. Steidl, Karin: Travel support and speaker honoraria from Abbvie, Takeda, Falk Johnson&Johnson Astropharma Afasigma MSD Boston Scientific No other conflicts of interest are declared Gröchenig, Hans Peter: Travel support and speaker honoraria from Abbvie, Takeda, Lilly and Johnson&Johnson
Müller et al. (Thu,) studied this question.