Scientists discover blood signature of chronic fatigue

Chronic fatigue syndrome, also known as myalgic encephalomyelitis (ME/CFS), is one of medicine’s most mysterious disorders. It leaves people exhausted even after rest, while doctors often struggle for years to make a clear diagnosis. The new study revealed that the disease leaves a unique epigenetic trace in the blood, one that can now be “read” with remarkable precision.

The new diagnostic technology, called EpiSwitch® CFS, was developed after scientists compared the 3D structure of DNA in blood samples from 47 severely ill patients and 61 healthy individuals. They found that in ME/CFS patients, genes responsible for immune and inflammatory responses are folded differently, creating a distinctive molecular pattern that serves as a biomarker for the condition.

Researchers paid special attention to interleukin-2 (IL-2), a key molecule that regulates T-cell activity in the immune system. IL-2 appears to act as a central hub for immune dysregulation in ME/CFS. Interestingly, the same pathways are targeted by drugs such as rituximab and glatiramer acetate, which are used to treat multiple sclerosis. This suggests that, in the future, some ME/CFS patients may benefit from personalized therapies tailored to their epigenetic profiles.

According to the authors, the test could not only enable earlier and more accurate diagnosis but also unlock a deeper understanding of the disease’s mechanisms, a goal medicine has been pursuing for decades. The Oxford team is now preparing for large-scale international trials to determine whether the test is equally effective in patients with milder forms of chronic fatigue syndrome.

Earlier, it was reported that the 2025 Nobel Prize in Chemistry was awarded to Japanese chemist Susumu Kitagawa, Australian Richard Robson, and American Omar Yaghi for their development of “a new form of molecular architecture.”