June 12, 2026, 8:14 am | Read time: 5 minutes
Chronic inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis have puzzled researchers for years, as their exact cause has not yet been clearly identified. A new study now provides a surprising clue. In a clearly defined patient group, scientists found a characteristic closely linked to a specific genetic variant. The discovery could open new perspectives on the development of these diseases and enable individualized treatment options.
What Was Studied and How the Study Was Conducted
The researchers wanted to find out whether a previously overlooked immune system malfunction plays a role in Crohn’s disease and ulcerative colitis. They focused on so-called autoantibodies against interleukin-10 (IL-10) and the question of how frequently they occur in affected individuals. Additionally, the scientists examined whether their occurrence is linked to certain genetic factors—particularly a gene variant called HLA-DRB1*01:03, which is considered an important risk factor for ulcerative colitis.
For the study conducted by the University of Oxford (in collaboration with researchers from Newcastle University and Cambridge University Hospitals), scientists analyzed blood samples from nearly 4,909 people with chronic inflammatory bowel diseases and about 1,006 healthy individuals.1 They also evaluated the participants’ genetic data to identify possible connections between gene variants and the occurrence of autoantibodies.
Interleukin-10 is a kind of natural “inflammation brake” for the immune system. This messenger substance ensures that inflammatory reactions do not get out of control. It is already known that rare genetic defects can impair its effect. Additionally, autoantibodies against IL-10 have occasionally been described—misguided antibodies that target the body’s own structures and can disrupt the protective function of the messenger substance.
When the Body’s Own Inflammation Brake Fails
The researchers found the autoantibodies in 173 out of a total of 4,909 people with Crohn’s disease or ulcerative colitis. This corresponds to about 3.5 percent of the patients examined. In the control group of 1,006 healthy participants, not a single case was detected.
Further analyses suggested that the autoantibodies indeed impair the protective function of interleukin-10. In affected individuals, less of the anti-inflammatory messenger substance was detectable, and at the same time, researchers found evidence of increased inflammatory activity.
Particularly striking was the connection to a specific gene variant called HLA-DRB1*01:03. People carrying this variant had a significantly higher risk of developing the autoantibodies. This connection was independently observed in several large patient cohorts and confirmed by additional genetic analyses.
A Small Patient Group Provides Important Clues
The results could help to better understand previously unknown disease mechanisms in Crohn’s disease and ulcerative colitis. Although the phenomenon was observed in only a small portion of patients, the findings point to a clearly distinguishable subgroup with specific biological characteristics.
Particularly interesting for the researchers is one aspect: The effect of the autoantibodies resembles a very rare, congenital form of chronic inflammatory bowel disease that usually occurs in children with severe genetic defects. However, in the newly identified patients, the gene itself is not disrupted. Instead, the autoantibodies block the anti-inflammatory messenger substance interleukin-10 and could trigger a similar effect.
The exact role this mechanism plays in the development and progression of the diseases is still unclear. However, the results provide new clues about how genetic factors and immune system malfunctions might interact.
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Study Assessment and Possible Limitations
The strengths of the study include the large number of participants, with nearly 5,000 people with chronic inflammatory bowel diseases, and the verification of results in several independent patient groups. Additionally, the researchers were able to show that the detected autoantibodies are not only present but also appear to influence the immune response.
However, the study also has limitations. It cannot be determined whether the autoantibodies contribute to the development of the disease or arise as a result of chronic inflammation. While the results show a close connection, they do not prove a cause-and-effect relationship.
Moreover, the autoantibodies were found in only a small portion of patients. Therefore, the results cannot be generalized to all people with Crohn’s disease or ulcerative colitis.
What the Researchers Say About the Results
Nevertheless, the researchers see the results as an important advancement. “For decades, we have suspected that interleukin-10 plays a crucial role in patients with chronic inflammatory bowel diseases,” says study author Professor Holm Uhlig from the University of Oxford in a press release.2 The new data now provide clear evidence of this connection and could explain a link between a known genetic risk variant and the recently discovered autoimmune reaction against interleukin-10.
The significance of the discovery from the researchers’ perspective is also highlighted by co-author Professor Simon Travis from the University of Oxford: “This is the most exciting discovery in my entire career as an IBD specialist. We can now identify a patient group for whom we know the cause of the disease.” The scientist sees this as an opportunity to fundamentally change the treatment of chronic inflammatory bowel diseases in the future.
What does this mean specifically for those affected? The findings of the current study could lead to the development of a blood test that can quickly identify affected patients. They could then be offered targeted therapy that directly addresses the cause—the misguided antibodies. This could not only improve quality of life but also avoid unnecessary surgeries or costly treatments without success.