A simple blood test could one day identify people who are likely to develop Crohn’s disease long before symptoms begin, opening the door to earlier diagnosis and even prevention, according to scientists.
Researchers at Mount Sinai Hospital’s Center for Inflammatory Bowel Disease in New York studied more than 380 people who were considered at high risk because they were close relatives of Crohn’s patients.
Crohn’s disease is a chronic condition in which the immune system mistakenly attacks healthy tissue in the digestive tract, causing symptoms such as abdominal pain, diarrhoea, blood or mucus in the stool, fatigue and weight loss.
Using advanced computer analysis, the researchers measured participants’ immune responses to a protein found on gut bacteria known as flagellin. They discovered that more than one-third of participants had elevated antibody levels linked to Crohn’s disease, even though they were not yet ill.
Study lead author Dr Ken Croitoru said the team wanted to find out whether people who were still healthy but at risk already showed signs of immune activity linked to the disease.
“We asked whether people at risk of Crohn’s disease, who are currently healthy, already carry antibodies against flagellin,” he said. “We found that many of them do.”
The study, published in Clinical Gastroenterology and Hepatology, suggests that abnormal immune responses to gut bacteria may occur years before symptoms appear and may help trigger the disease rather than simply result from it.
Researchers followed 381 first-degree relatives of Crohn’s patients over time. Of these, 77 went on to develop the disease about two and a half years later. Among them, 28 had previously shown elevated antibody levels, strengthening the link between early immune reactions and later illness.
The strongest immune responses were seen in siblings, pointing to the combined influence of genetics and shared environmental exposure.
Dr Sun-Ho Lee, a co-author of the study, said the findings could lead to preventive treatments in the future.
“Our results raise the possibility of developing a vaccine that targets flagellin in selected high-risk individuals to prevent Crohn’s disease,” he said.
Crohn’s disease affects around half a million people in the UK and can also cause joint pain, eye problems and complications around the anus. About one-third of patients eventually require surgery.
Treatment currently relies on drugs known as biologics, which suppress harmful immune activity, though not all patients respond well to them. A newer medication, guselkumab, is being reviewed by health authorities after studies showed it could relieve symptoms in many patients within three months.
Researchers say further studies are now needed to confirm whether the blood test can reliably predict Crohn’s disease and help doctors intervene before irreversible damage occurs.
