Scientists Discover the Body’s Hidden “Off Switch” for Inflammation, Opening New Path to Safer Treatments
Scientists have identified a previously underappreciated biological mechanism that helps the human body naturally shut down inflammation, potentially opening a new route toward treatments for chronic inflammatory diseases.
Researchers at University College London (UCL) found that a group of fat-derived molecules called epoxy-oxylipins can act as natural brakes on the immune system. The molecules appear to prevent the excessive buildup of certain immune cells that can keep inflammation going after the original threat has disappeared.
Inflammation is normally a protective response. It helps the body fight infections and repair damaged tissue. The problem arises when the immune response fails to switch off and continues attacking or irritating healthy tissue, contributing to conditions such as arthritis, cardiovascular disease and diabetes.
The new research helps explain an important question in immunology: how does the body know when to stop fighting and begin repairing?
The researchers focused on intermediate monocytes, a type of white blood cell involved in inflammatory responses. These cells can be useful during the early stages of an immune reaction, but excessive accumulation may contribute to persistent inflammation.
The team discovered that epoxy-oxylipins help limit the expansion of these cells. One molecule in particular, 12,13-EpOME, was found to interfere with the p38 MAPK signalling pathway, which plays a role in the transformation and activity of monocytes.
To test the mechanism in humans, researchers created a controlled inflammatory response in healthy volunteers by injecting a very small amount of UV-killed E. coli bacteria into the forearm. Because the bacteria were no longer alive, they could not cause an infection, but they could still trigger temporary inflammation, producing pain, redness, heat and swelling.
The scientists then tested GSK2256294, a drug that blocks an enzyme called soluble epoxide hydrolase, or sEH. This enzyme normally breaks down epoxy-oxylipins. Blocking it therefore allows greater amounts of the potentially protective molecules to remain available.
The study included separate groups in which the drug was administered either before inflammation began or several hours after the inflammatory response had started. In both approaches, increasing epoxy-oxylipin levels was associated with faster resolution of pain and a substantial reduction in intermediate monocytes in blood and tissue.
Importantly, the research does not mean that scientists have discovered a universal cure for inflammation. The human experiment involved a carefully controlled, short-lived inflammatory response in healthy volunteers, rather than patients suffering from chronic inflammatory disease.
The significance lies in the possibility of restoring the body’s own inflammatory braking system rather than broadly suppressing immunity. Many existing anti-inflammatory and immunosuppressive treatments work by blocking immune activity, which can sometimes interfere with the body’s ability to fight infections.
Researchers believe that targeting the sEH–epoxy-oxylipin pathway could eventually provide a more selective approach. Future clinical studies could investigate whether drugs acting on this pathway can help people with conditions such as rheumatoid arthritis and cardiovascular disease.
The findings were published in Nature Communications in January 2026 in a study titled “Epoxy-oxylipins direct monocyte fate in inflammatory resolution in humans.” The research involved scientists from UCL, King’s College London, the University of Oxford, Queen Mary University of London and the U.S. National Institute of Environmental Health Sciences.
The discovery is particularly significant because modern medicine has spent decades studying how inflammation starts, while comparatively less attention has been devoted to understanding how the body naturally brings the response to an end.
By identifying one of the mechanisms involved in that shutdown process, the researchers have provided a new biological target for drug development.
For patients with chronic inflammatory diseases, the ultimate promise is not simply to suppress the immune system, but to help the body regain control of an immune response that has failed to switch itself off. That possibility will now need to be tested in larger and longer clinical trials before its medical potential can be established.
