New research links chronic fatigue and overactive immune response
New research from King’s College London finds that an exaggerated immune response can trigger long-lasting fatigue, potentially explaining how chronic fatigue syndrome (CFS) begins. The study, published in the journal Psychoneuroendocrinology, is the most in-depth biological investigation yet into the role of the immune system in lasting symptoms of fatigue.
CFS, also known as myalgic encephalomyelitis (ME), is a long-term illness which is characterised by extreme tiredness. The underlying biology of CFS has remained a mystery, hampering the search for treatments. There is some evidence that the immune system plays a role in triggering CFS and many patients report their illness starting with a challenge to the immune system such as a viral illness.
By the time patients are diagnosed it is too late to catch CFS in its earliest stages, and it is impossible to assess the biology of patients before the illness develops. To overcome this problem, researchers from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London used a model for CFS based on a treatment for hepatitis C called interferon-alpha.
Interferon-alpha activates the immune system in the same way as a powerful infection. A number of patients develop acute fatigue during treatment with interferon-alpha and a minority go on to have a CFS-like illness, where fatigue lasts for more than six months after the treatment ends. The researchers measured fatigue and immune system markers in 55 patients before, during and after treatment with interferon-alpha, tracking which people developed the persistent CFS-like illness.
The team found differences in the immune systems of 18 patients who developed lasting fatigue compared to those who recovered as normal. During treatment with interferon-alpha there was a much bigger immune response among those who developed the CFS-like illness, with a doubling in the levels of immune system ‘messenger’ molecules interleukin-10 and interleukin-6.
Importantly, even before treatment started, levels of interleukin-10 were higher among those who went on to have lasting fatigue, suggesting the immune system may have been ‘primed’ to over-respond.
Lead researcher Dr Alice Russell from the IoPPN says:
For the first time, we have shown that people who are prone to develop a CFS-like illness have an overactive immune system, both before and during a challenge to the immune system. Our findings suggest that people who have an exaggerated immune response to a trigger may be more at risk of developing CFS.
Read more on the King’s College London website.
The King’s Health Partners Genetics, Rheumatology, Infection, Immunology and Dermatology Clinical Academic Group promotes academic input into the delivery of state-of-the-art clinical services, fuels investigative clinical research, and promotes the translation of basic science discoveries.