Study finds blood antibody patterns up to 10 years before Crohn's and colitis diagnosis

Researchers have found distinct antibody patterns in the blood of people who went on to develop inflammatory bowel disease (IBD). The patterns appeared up to about 10 years before diagnosis of Crohn's disease or ulcerative colitis.

The team, led by Dr Arno Bourgonje, analysed 2,000 blood (serum) samples from 500 people. Of these, 200 later developed Crohn's disease and 200 later developed ulcerative colitis. The other 100 developed neither condition. Medical Xpress describes them as age- and sex-matched healthy controls.

The samples were screened for antibody responses against hundreds of thousands of protein fragments. These came from microbes, viruses, food and the body's own tissues. Medical Xpress gives the figure as around 357,000.

In people who later developed Crohn's disease, antibody responses against viruses were elevated. The Guardian specifies Epstein-Barr virus. Medical Xpress refers to herpesviruses. This signal was stronger in people who later developed complicated disease. People who later developed ulcerative colitis showed a different pattern. It included antibodies against the body's own proteins.

The findings were presented at UEG Week 2026, the United European Gastroenterology meeting. According to the Guardian, the meeting took place in Barcelona, the findings were published in the journal Gut, and the samples came from US military personnel.

According to Medical Xpress, samples were collected at diagnosis and about two, four and 10 years earlier. The outlet reports that antibody diversity was significantly lower in people who later developed IBD. It also reports that machine-learning models distinguished future Crohn's disease and ulcerative colitis from healthy controls, with AUC values of 0.90 and 0.84.

The researchers say the findings must be validated in other populations before they can become a clinical test. According to the Guardian, the results show a link, not proof that infections cause IBD. The Guardian reports that at least 3.8 million people worldwide live with IBD.

What each side says

The Guardian quoted Bourgonje as saying: "What we have shown is that the disease begins years before symptoms appear, and the immune system leaves warning signs long before diagnosis." He added: "This is not yet a test that can tell someone they will become ill, but it is an important step towards catching the disease earlier and, one day, preventing it."

Medical Xpress quoted him as saying: "The next priority is to validate these signatures in independent, more diverse and prospectively followed populations."

James Lindsay, a professor of gastroenterology at Barts Health who was not involved, called the techniques "very much a research tool", according to the Guardian. Marianne Radcliffe, chief executive of Crohn's & Colitis UK, said research like this is "an important step forward", the Guardian reported.

The reports reviewed by Vocemundi do not describe the study's funding or any declared conflicts of interest.

Analysis

The study suggests the immune system may show measurable changes long before IBD symptoms appear. If later studies confirm this, antibody profiling could one day help identify people at higher risk or those likely to develop complicated disease. Several open questions remain. The results come from one study. The reports describe limited detail on the cohort, so it is unclear how well the findings apply to other groups. The reports also do not show whether the antibodies play any causal role. Validation, cost and proof of better patient outcomes would all be needed before any clinical use.

Produced by the Vocemundi newsroom with AI assistance.