H&E stain of rectal biopsy, showing a large nucleus (arrow) with a smudged, eosinophilic chromatin pattern consistent with cytomegalovirus colitis. Credit: Viruses (2025). DOI: 10.3390/v17060752

Cytomegalovirus (CMV), a common virus in the Herpesviridae family, infects approximately half of all adults in the United States, most of whom experience mild or no symptoms. While the virus usually remains latent in the body, CMV reactivation is more prevalent in immunocompromised individuals, including people with inflammatory bowel disease (IBD). Individuals with IBD are more susceptible to CMV reactivation because of chronic gut inflammation and the use of immunosuppressive medications.

When CMV reactivates, it can involve the colon, particularly in patients with IBD. This form of CMV infection, known as CMV colitis, is frequently underrecognized or misdiagnosed, according to Yale School of Medicine's Alfredo Puing, MD, who notes that the symptoms of CMV colitis, such as abdominal pain and fever, often mimic an IBD flare.

The overlap in presentation between IBD flares and CMV colitis can complicate diagnosis, treatment, and management, says Puing, an assistant professor of medicine (infectious diseases). To help address this clinical challenge, he published an updated review article on the topic in the journal Viruses.

In a Q&A, Puing discusses what he learned from reviewing the latest research on CMV colitis in adult patients with IBD and the importance of raising awareness about this condition.

Why is it important to study CMV colitis?

More and more often, patients are being diagnosed with IBD, and they are receiving new therapies and having their immunosuppression escalated with these therapies. It's important for us to be aware of potential complications because treating CMV colitis is a balance of how much immunosuppression you want to withdraw to allow the infection to clear versus how much antiviral medication you want to give. Because this is not an easy decision to make, it is useful to have clear guidance.

What does newer research show about approaches to treating and managing CMV colitis?

With this review, we were able to capture what kind of immunotherapy you use to treat a patient with an IBD flare concomitant with a CMV infection to allow for the inflammation to decrease while also allowing for the viral infection to clear. Steroids and corticosteroids are agents that we usually like to withdraw.

However, newer biologic and targeted therapies may allow continuation of IBD treatment during antiviral therapy for CMV. Depending on the mechanism of action, we don't necessarily need to stop the treatment of IBD while treating the CMV infection.

What is the goal of your recently published review of the latest research on CMV colitis in adult patients with IBD?

My goal is to raise awareness of CMV colitis as a potential cause of IBD flare that fails to respond to standard therapies. There are numerous guidelines and recommendations for managing CMV in solid organ and stem cell transplant recipients. But the data on patients who are immunocompromised due to IBD therapies rather than transplantation or hematological malignancies is limited.

The objective of this review was to synthesize the latest research to help infectious diseases and gastroenterology specialists navigate this complex scenario.

We usually just treat and manage this patient population based on the available data and guidelines that we have on other types of immunocompromised populations. The idea was to develop a set of recommendations tailored for these patients because they need some kind of immunosuppressive or immunomodulatory therapy for their underlying inflammatory disease.

It is important to navigate that in terms of what medications should be avoided, restarted, or continued for IBD while treating CMV colitis. Lastly, we needed a better sense of how long to treat CMV in this population.

The more information we have, the more we can improve outcomes and quality of care for these patients.

More information: Kriti Soni et al, Cytomegalovirus Colitis in Adult Patients with Inflammatory Bowel Disease, Viruses (2025). DOI: 10.3390/v17060752