Scientists have identified immune-system changes that can precede inflammatory bowel disease (IBD) by as much as a decade, potentially opening a new window into how Crohn’s disease and ulcerative colitis develop.
Looking back before symptoms
Researchers at the Icahn School of Medicine at Mount Sinai examined roughly 2,000 stored blood samples from 200 people who later developed Crohn’s disease, 200 who developed ulcerative colitis and 100 healthy controls. The samples were collected at different times before diagnosis, allowing scientists to observe changes before symptoms became clinically apparent.
What changed in the blood?
Using a high-throughput method to examine antibody responses to about 357,000 antigens, the team found distinct immune patterns. In people who later developed Crohn’s disease, elevated responses to Epstein-Barr virus and bacterial flagellins could be detected as early as ten years before diagnosis. Patterns differed among people who later developed ulcerative colitis.
Why it matters
IBD is usually diagnosed after symptoms such as chronic diarrhea, abdominal pain, bleeding or weight loss prompt evaluation. Detecting an earlier immune phase could help researchers understand disease origins and eventually develop risk assessment or preventive strategies.
Not a screening test yet
These findings do not establish a clinically validated blood test for IBD. An antibody signature is not a diagnosis, and most people with antibodies to common infections will not develop Crohn’s disease. Larger prospective studies are needed to determine predictive accuracy and whether earlier interventions improve outcomes.
The study was published in Gut on July 21, 2026. Its implications remain relevant as researchers explore the silent years preceding inflammatory illness.
Sources: Gut research paper; Mount Sinai research summary.
