Chronic fatigue syndrome connected with an overactive immune system

By Dr. Ananya Mandal, MDDec 19 2018

A new study has shown that overactive immune systems may be the trigger that gives rise to chronic fatigue syndrome (CFS). The study results were published in the latest issue of the journal Psychoneuroendocrinology.

The team of researchers from the King's College London looked at the connection between sensitive immune system and CFS. Chronic fatigue syndrome is associated with long term fatigue that refuses to go away even after the infection is controlled.

Alice Russell, a psychiatrist at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) who works with CFS or myalgic encephalomyelitis (ME) 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.”

The team explains that CFS or ME is a condition that manifests as fatigue that refuses to go away that makes people unable to perform their daily activities. Patients spend their time sleeping or laying bed. The condition affects around 17 to 24 million individuals worldwide who are often not diagnosed and seldom treated. Research in this area is fairly recent they explain. The team now finds that the immune system has a lot to do with the condition and it is not a psychological condition as believed earlier.

The researchers looked at a model that can mimic the symptoms of CFS to understand its cause. They included 55 patients with Hepatitis C and these patients were given Interferon alfa as part of their treatment. Interferon alfa is the standard treatment for Hepatitis C and mimics the effects of the immune system when it goes into an overdrive to fight an infection. Interferon alfa can cause fatigue as a side effect and even after the therapy is completed, the drug can cause long lasting fatigue that is similar to CFS.

The team noted that 18 of the patients did not recover from the symptoms of fatigue long after the treatment. These patients had similar levels of fatigue as other patients before their treatment started. However their fatigue symptoms worsened and lasted longer than others once the treatment began and then was completed. They found that the fatigue in these patients was linked to a greater immune response compared to the other patients. This means that in some individuals the immune systems are “primed” so that they give an exaggerated response to infections and this can lead to long lasting fatigue, they write. Six months after the treatment was completed, these patients still complained of fatigue.

The researchers were surprised to note that the immune systems of the 54 patients with CFS were similar to 57 individuals who were healthy controls. This means that once the condition develops, the differences in the immune system are no longer detectable, the authors of the study explain. This could be the reason why CFS is difficult to diagnose, the team explains.

Co-author Carmine Pariante, an expert in biological psychiatry at King's College says, “A better understanding of the biology underlying the development of CFS is needed to help patients suffering with this debilitating condition. Although screening tests are a long way off, our results are the first step in identifying those at risk and catching the illness in its crucial early stages.”

Authors write in their concluding remarks, “In conclusion, findings from this study support the hypothesis that abnormal immune mechanisms are important in CFS, but only early in the course of the illness, around the time of the trigger, rather than when the syndrome is established…Moreover, our study confirms the importance of the acute fatigue response to the trigger, rather than of the recovery period preceding the illness.”

According to Dr Neha Issar-Brown, of the Medical Research Council (MRC), “: CFS/ME is a serious condition and its underpinning biology is poorly understood… Encouragingly, this work sheds light on potential mechanisms of immune dysregulation underlying early stages of chronic fatigue syndrome… The MRC strongly encourages more research to better understand this condition in order to address an area of unmet clinical need.” MRC funded this study.