Researchers at Mount Sinai have found that distinctive antibody patterns in the blood can appear up to ten years before a person is diagnosed with Crohn's disease or ulcerative colitis, according to a study published in the journal Gut.
The team analyzed nearly 2,000 blood samples, collected over roughly a decade, from people who later went on to develop one of the two conditions, known together as inflammatory bowel disease (IBD). They found that antibody diversity against common viruses and bacteria — particularly Epstein-Barr virus and bacterial flagellin proteins — was significantly lower in people who later developed Crohn's or ulcerative colitis than in healthy controls, with distinct, measurable differences evident as much as a decade ahead of diagnosis.
A silent phase that might not stay silent
IBD is already understood to have a long asymptomatic or minimally symptomatic phase before diagnosis, but researchers have had few reliable ways to detect it early. The Mount Sinai findings suggest the immune system is doing something measurably different years before gut symptoms become apparent — raising the possibility, though not yet the practice, of identifying high-risk individuals long before disease onset.
The researchers frame the work explicitly as a step toward earlier detection and, eventually, prevention, rather than a finished screening tool. The findings build on earlier work: a 2023 study from the Francis Crick Institute and Aalborg University, using routine blood tests, found measurable variation up to eight years before Crohn's diagnosis and three years before ulcerative colitis diagnosis, and flagged fecal calprotectin — a marker released during bowel inflammation — as another early signal.
Unique antibody signatures were present years before diagnosis.
Findings summarized in coverage of the Mount Sinai study
Not a test patients can ask for yet
Both the new study and its 2023 predecessor are research findings rather than validated clinical screening tools, and neither offers guidance for patients on specific symptoms to watch for in the years before diagnosis. IBD affects millions of people worldwide and can take years to diagnose correctly even after symptoms appear, in part because early gut symptoms overlap with many less serious conditions.
What happens next
The Mount Sinai team says its next step is determining whether the antibody signatures they identified could be refined into a practical blood test, and whether earlier identification of high-risk patients would actually change outcomes if confirmed by larger, prospective studies. For now, the findings add to a small but growing body of evidence that IBD's biological footprint begins long before a diagnosis is made.