The blood samples were screened for antibodies that the immune system might have churned out in response to hundreds of thousands of fragments of proteins from bacteria, viruses, food and even the body's own tissues.
Research shows that antibody patterns in people's blood could predict the onset of inflammatory bowel disease (IBD) a decade before diagnosis.
At least 3.8 million people worldwide live with IBD, an immune condition that drives chronic inflammation of the digestive tract, causing pain, diarrhoea and fatigue.
Scientists found that the immune system sends warning signals up to a decade before diagnosis, paving the way for potentially earlier detection and even prevention.
In people who went on to develop Crohn's disease, antibodies against Epstein-Barr virus, which causes glandular fever, were more common, and the differences were already visible a decade before diagnosis.
“What we have shown is that the disease begins years before symptoms appear, and the immune system leaves warning signs long before diagnosis,” Bourgonje added.