A major scientific breakthrough offers new hope for individuals at risk of developing Crohn’s Disease (CD), a chronic and debilitating inflammatory bowel condition. Researchers at Mount Sinai Hospital’s Center for Inflammatory Bowel Disease (IBD) in New York have developed a simple blood test capable of predicting who may develop the disease later in life, paving the way for earlier diagnosis and potential prevention strategies.

Crohn’s disease occurs when the immune system mistakenly attacks healthy tissue in the gut and other parts of the body, leading to severe symptoms such as abdominal pain, persistent diarrhea, blood or mucus in the stool, fatigue, loss of appetite, unexplained weight loss, and, in children, delayed puberty. Approximately half a million people in the UK are affected, with up to a third eventually requiring surgery.

The innovative blood test identifies specific immune responses. Researchers collected samples from over 380 individuals at high risk for CD, primarily first-degree relatives of Crohn’s patients. Using advanced computer imaging, they measured immune responses to flagellin, a protein found on gut bacteria. Dr. Ken Croitoru, the study’s lead author, explained: “We wanted to know: do people who are at risk of developing the disease, who are healthy now, have these antibodies against flagellin. We looked, we measured, and yes indeed, some of them did.” More than a third of these high-risk participants exhibited elevated antibody responses linked to the disease.

Published in Clinical Gastroenterology and Hepatology, the study highlights the critical interaction between gut bacteria and the immune system in Crohn’s development. Previous research from the Genetic Environmental and Microbial Project (GEM Project) showed that inflammatory immune responses to gut bacteria often precede symptoms. In Crohn’s patients, the immune system targets beneficial gut microbes, leading to elevated antibodies against proteins like flagellin.

Of the 381 first-degree relatives studied, 77 eventually developed Crohn’s approximately two and a half years later. Notably, 28 had shown elevated antibody responses, suggesting this immune reaction contributes to disease onset. Responses were strongest in siblings, indicating shared environmental and genetic influences.

Dr. Sun-Ho Lee, co-author, noted: “Our findings raise the potential for designing a flagellin-directed vaccine in selected high-risk individuals for prevention of disease.” On the treatment front, biologic drugs remain the standard, though not all patients respond effectively. The NHS is reviewing guselkumab, a once-monthly injection that targets damaging immune cells, eliminating symptoms within three months for over half of patients with aggressive Crohn’s. At approximately £2,250 per month, experts hail it as a significant addition to the Health Service’s arsenal against bowel disease. The research team is now working to validate these findings through further studies.