Antibody patterns detectable in blood may reveal inflammatory bowel disease (IBD) as much as ten years before a patient is diagnosed, according to research reported by The Guardian. The study examined stored blood samples from US military personnel and found that people who later developed Crohn's disease or ulcerative colitis carried distinct immune signatures long before any symptoms appeared. The findings were published in the journal Gut and presented at the United European Gastroenterology meeting in Barcelona.
Why it matters
Crohn's disease and ulcerative colitis are the two main forms of IBD, a condition in which a malfunctioning immune system drives chronic inflammation of the digestive tract. The Guardian reports that at least 3.8 million people worldwide live with IBD, which causes pain, diarrhoea and fatigue. Its exact cause remains unknown, though genetics, gut microbes and immune dysfunction are all thought to play a part.
Current treatment begins only after symptoms emerge, by which point the gut has already sustained damage. Patients are usually given anti-inflammatory and immune-suppressing drugs, but many do not respond well, and a substantial number eventually need surgery to remove diseased sections of bowel. The Guardian notes that prolonged inflammation also increases the risk of bowel cancer. Finding a way to identify at-risk people earlier could therefore change how the disease is managed, and possibly prevent it altogether.
How the study was carried out
The work was led by Dr Arno Bourgonje, who holds positions at the University Medical Centre Groningen in the Netherlands and the Icahn School of Medicine at Mount Sinai in New York. He worked with colleagues at Mount Sinai and the Medical University of Vienna.
The team analysed 2,000 blood samples drawn from 500 individuals. Of these, 200 later developed Crohn's disease and 200 went on to develop ulcerative colitis, while the remaining 100 developed neither condition. The samples were tested for antibodies produced by the immune system against hundreds of thousands of protein fragments originating from bacteria, viruses, food and the body's own tissues.
The two diseases produced different antibody profiles. Among people who later developed Crohn's disease, antibodies against Epstein-Barr virus — the pathogen behind glandular fever — appeared more frequently, and this difference was detectable a decade before diagnosis. The signal was most pronounced in those who went on to develop more severe, complicated disease, including forms that narrow the bowel or create abnormal channels. Those who developed ulcerative colitis showed a separate pattern, which included antibodies directed at one of the body's own proteins.
Bourgonje said the field had for too long been limited to treating IBD after damage had occurred, which for many patients comes too late. According to The Guardian, he described the results as showing that the disease process starts years before symptoms surface and that the immune system leaves detectable clues well in advance. He was careful to stress that this is not yet a test capable of telling an individual they will become ill, but rather a step toward earlier detection and, eventually, prevention.
Expert caution and the road ahead
The authors acknowledge that the findings must be replicated in other populations. The Guardian reports that the results demonstrate an association rather than proving that any infection causes IBD.
James Lindsay, a professor of gastroenterology at Barts Health who was not involved in the study, told The Guardian that the research offers important insights into what drives Crohn's disease and ulcerative colitis and could add new tools for identifying people at risk. He also cautioned that the techniques remain very much a research tool and are not yet ready for use in the clinic.
Marianne Radcliffe, chief executive of the patient charity Crohn's & Colitis UK, said research of this kind represents meaningful progress for people living with the conditions, adding that each new finding helps clarify how they develop, including changes that may take place years before symptoms appear.
The study's authors point to type 1 diabetes as a possible model. In that disease, a blood test can already identify people whose immune systems have started attacking the pancreas before symptoms arise, allowing treatment that postpones onset. Whether IBD can follow a similar path will depend on validation in broader groups and on the development of a practical clinical test.
Watch for independent replication of these antibody signatures in other cohorts, which would be the next step toward any screening tool.
