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Blood Viral Patterns May Signal Crohn’s Disease

Researchers have identified differences in the viruses circulating in the blood of people with Crohn’s disease, suggesting that the “blood virome” could serve as a disease signature.

Crohn’s disease has long been linked to changes in the gut microbiome. However, the gut virome is highly variable between individuals, making it difficult to use as a consistent marker of disease.

In this study, researchers analyzed blood and stool samples from 15 patients with Crohn’s disease and 14 healthy individuals using metagenomic sequencing.

They confirmed that blood is not sterile. Both healthy individuals and patients with Crohn’s disease had detectable viruses in their blood, primarily bacteriophages, which are viruses that infect bacteria. The total number of viral particles in blood was similar between groups, and overall diversity was also similar. The key difference was in composition.

While fecal viral communities did not clearly separate patients from healthy controls, the blood viral communities did.

Statistical analysis showed a significant difference in blood virome composition between the two groups, in particular:

  • Phages targeting Acinetobacter were more abundant in healthy individuals.
  • A distinct set of phages, including some predicted to infect intestinal bacteria, were enriched in Crohn’s disease.

The authors suggest that increased intestinal barrier dysfunction in Crohn’s disease may allow viral particles to move from the gut into the bloodstream.

If validated in larger studies, blood viral patterns could serve as biomarkers for Crohn’s disease. Notably, the blood virome appeared more discriminatory than the gut virome in this small cohort.

However, this proposed mechanism is based on metagenomic data and requires further confirmation, and the study has important limitations:

  • Small sample size
  • Mixed disease states (remission and flare)
  • Mechanistic conclusions not yet confirmed

For now, these findings represent an early research signal rather than a clinical tool.

Living With Crohn’s Disease

While researchers continue working to better understand the biological signatures of Crohn’s disease, people living with the condition navigate its realities every day.

At GAI, members of our community have shared powerful personal stories about diagnosis delays, stigma, coexisting conditions, and learning to advocate for themselves:

Their experiences highlight what research alone cannot capture: the complexity of living with inflammatory bowel disease and the importance of early recognition, support, and compassionate care.

You can explore these and other stories in our Autoimmune Stories collection.

Citation

Lamy-Besnier, Q., Theodorou, I., Sokol, H., De Paepe, M., Petit, M. A., De Sordi, L., & Blood Virome Working Group (2025). The Human Blood Virome Differs in Crohn’s Disease. Gastroenterology, S0016-5085(25)06122-0. Advance online publication. https://doi.org/10.1053/j.gastro.2025.10.007