(CNN) Chronic fatigue syndrome, a condition that causes extreme tiredness, could be triggered by an overactive immune system, a study has found. 
 
 UK researchers found that an exaggerated immune response can trigger long-lasting fatigue, suggesting this is how the condition -- also known as myalgic encephalomyelitis or ME -- begins. 
 
 Limited insight to date has made treatment a challenge. 
 
 Pariante explained that in a lot of chronic fatigue cases, patients remember an infection, such as a very bad cold or other viral infection, in the early stages of developing the condition. 
 
 "We had this information for quite a long time but didn't know what was going on in the body of these patients," he said. 
 
 836,000 to 2.5 million Americans struggle with the syndrome, according to the Around 250,000 people in the UK and 17 million people worldwide are affected by chronic fatigue, according to British charity Action on ME . An estimated836,000 to 2.5 million Americans struggle with the syndrome, according to the CDC 
 
 To try to find out more about it, the team modeled a possible route to the condition based on a treatment for chronic hepatitis C infections called interpheron alpha, because the treatment is known to induce persistent fatigue in some people. 
 
 Interpheron alpha affects the immune system in a similar way to a strong infection, the study explains. 
 
 Researchers measured fatigue and immune activity in 55 patients receiving hepatitis C treatment with interferon-alpha. 
 
 Patients were followed up before, during and after the hepatitis C therapy. Of the participants, 18 patients -- about a third -- developed lasting fatigue, defined as fatigue lasting longer than six months after treatment. 
 
 The group with lasting fatigue also experienced a greater immune response -- shown by a doubling in the levels of immune system messenger molecules interleukin-10 and interleukin-6. 
 
 Immune markers were measured with a blood test during the study. 
 
 The team also saw higher levels of these molecules in these patients before treatment had even begun. 
 
 "What this data strongly suggest is that people that develop CFS in response to an infection, they do so because their immune system is primed to hyper react," Pariante explained. Why a person's immune system could be primed to hyper react is unclear, but genetics could be a possible reason, he added. 
 
 Delayed diagnoses 
 
 Patients are often diagnosed with chronic fatigue five, six or even up to 10 years later, according to Pariante, because the diagnosis is based entirely on symptoms, such as headaches, difficulty concentrating and the inability to engage in activities. 
 
 By the time they are diagnosed, patients would have been ill for quite some time, making studies into the biology of people who develop the illness difficult, he added. 
 
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 Dr. Charles Shepherd, medical adviser to the ME Association in the UK, explained in an email that "many doctors still don't know how to diagnose and manage ME/CFS." 
 
 Shepherd, who was not involved in the study, said that a lack of research means "that we still don't have any effective forms of treatment." 
 
 Many people who have chronic fatigue find pacing helpful in managing their condition, according to the UK's National Health Service. Pacing requires people to balance rest and activity in order to avoid making their fatigue and other symptoms worse. 
 
 Shepherd said that the study "adds to the growing weight of scientific evidence which indicates that the body's immune system is playing an important role in the causation of ME/CFS." 
 
 The model the team used for the study "is relevant to the two most common causes" of chronic fatigue, Pariante said: a strong infection and a major stressful life event. 
 
 The study also found that "having quite severe acute fatigue during an infection, or shortly after infection" makes people more at risk of developing chronic fatigue, he added. 
 
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 Pariante hopes that once questions about why this happens are understood, future treatments and screening can be identified. 
 
 The study's small sample size was cited as a limitation by Pariante. More studies are needed to confirm its relevance to chronic fatigue patients, the paper says. 
 
 'Blackness descending' 
 
 Skye Wheeler, a 19-year old from Cambourne, Cornwall, is housebound due to her chronic fatigue syndrome. 
 
 "You can't get dressed and ready for the day without a blackness descending over your eyes. You can't carry a conversation, let alone even speak," she explained in a statement. 
 
 "The bottom of the line is that there is no energy there in the first place to channel through your body to all the right places. The only thing you can do is lie and exist," she said. 
 
 The condition affects many body systems, and people who have chronic fatigue syndrome feel debilitating pain and fatigue because their body and brain are unable to recover after even small efforts. 
 
 About a quarter of people affected by the condition are severe cases, meaning they are bedridden, house-bound or wheelchair-bound at some point in their illness, according to the ME Association. 

 Image copyright dragana991 Image caption Researchers linked an overactive immune system with ME-like symptoms 
 
 An overactive immune system may help explain the cause of chronic fatigue syndrome, scientists from King's College London have suggested. 
 
 Many sufferers of CFS, or ME, say their condition began with a challenge to their immune system like an infection. 
 
 The scientists studied 55 patients with Hepatitis C who were given a drug that causes a similar response to a virus. 
 
 Eighteen of those patients had an overactive immune system and went on to develop CFS-like symptoms. 
 
 'It is a light in the fog' 
 
 Chronic fatigue syndrome is a long-term illness characterised by extreme tiredness. 
 
 Scientists from the Institute of Psychiatry, Psychology and Neuroscience at King's College recruited 55 patients who had hepatitis C. A treatment for hepatitis C is the drug interferon-alpha which challenges the immune system in the same way as a powerful infection. 
 
 The team measured fatigue and immune markers before, during and after treatment, tracking which people developed the persistent CFS-like illness. 
 
 In the 18 patients who developed CFS-like symptoms the team found a much stronger immune response to the medication. Significantly these patients also had an overactive immune system before the treatment started. 
 
 Lead researcher Dr Alice Russell from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) said: 
 
 "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." 
 
 Senior researcher, Prof Carmine Pariante, added: "This is a light in the fog, a direction of travel. Although screening is a long way off, our results are the first step in identifying those at risk and catching the illness in its crucial early stages." 
 
 What is ME? 
 
 Myalgic encephalomyelitis or ME is also known as Chronic Fatigue Syndrome (CFS) 
 
 The long-term illness affects about 250,000 people in the UK 
 
 As well as fatigue, it can cause sleep problems and muscle and joint pain 
 
 Living with CFS/ME can be difficult. Extreme tiredness and other physical symptoms can make it hard to carry out everyday activities 
 
 There is currently no cure for ME 
 
 Source: NHS Choices 
 
 Dr Charles Shepherd, the ME Association's medical adviser, said: "This research adds to the growing weight of scientific evidence which indicates that the body's immune system is playing an important role in the causation of ME/CFS." 
 
 The study is one of five research projects funded by the Medical Research Council into the causes of ME. 
 
 In June, Scottish National Party MP Carol Monaghan led an emotional Westminster Hall debate into a common treatment, graded exercise therapy (Get), which is available on the NHS. She argued it was often damaging and in need of revision. Others defended the treatment. 
 
 The health watchdog, NICE, is currently updating its guidelines for treatment of CFS in England, but publication is not due until 2020. 

 An overactive immune response appears to be a trigger for persistent fatigue, say researchers in a study that could shed light on the causes of chronic fatigue syndrome. 
 
 Chronic fatigue syndrome (CFS) is a debilitating long-term condition in which individuals experience exhaustion that is not helped by rest, as well as pain, mental fogginess and trouble with memory and sleep. It is also known as myalgic encephalomyelitis (ME). 
 
 Some studies into the condition have suggested the immune system could be involved, with viral infections one potential trigger for CFS. 
 
 “The evidence is largely inconclusive – there are studies which have shown elevated levels of the inflammatory markers, but such abnormalities are quite inconsistent across studies,” said Alice Russell, first author of the research from King’s College London. 
 
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 Because it is not possible to predict who will get a virus, it is impossible to look at levels of biological molecules before, during and after a potential CFS “trigger” infection. 
 
 Experts say they have used a group of people with a different condition as a model to explore how immune response might be linked to persistent fatigue. 
 
 Writing in the journal Psychoneuroendocrinology, Russell and colleagues describe how they recruited 55 patients with a chronic hepatitis C infection. To treat the condition, all were given a six- to 12-month course of injections of interferon alpha, a protein that is produced naturally by the body and stimulates the white blood cells to provoke an immune response. The treatment has previously been linked to a side effect of ongoing fatigue in some patients. 
 
 While most patients recovered from hepatitis C, there was also an increase in fatigue during treatment, which reduced when the injections ended. 
 
 However, six months after treatment finished, 18 participants remained more fatigued than before treatment began. These patients had slightly higher levels of a protein linked to inflammation, called IL10, in their blood before treatment began, but, after four weeks of treatment, their levels of IL10 and another inflammatory protein called IL6 were twice as high as for those who recovered without persistent fatigue. 
 
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 However, six months after the injections of interferon alpha stopped, there were no differences in the levels of the inflammation proteins between those with and without persistent fatigue. There was also no difference in history of depression, experience of a recent stressful life event or early life trauma. 
 
 For comparison, the team took one-off measurements of the same inflammation markers among 54 individuals who have had CFS for years and 57 healthy participants, but they found no difference in their levels. 
 
 Prof Carmine Pariante, a co-author of the study from King’s College London, said this showed that by the time ongoing fatigue was established, the immune activation was no longer present. 
 
 “It helps explain why we cannot find clear evidence of immune activation in patients with chronic fatigue syndrome,” he said. Pariante added the heightened immune response might trigger changes in the brain, muscles or metabolism that resulted in ongoing fatigue – although this is not yet clear – while genetics or repeated childhood infections might explain why only some people had a heightened immune response. 
 
 However, the study had a number of limitations: it is small, the hepatitis C patients were largely men and, by default, all had a serious condition which itself is more common in individuals with particular risk factors. In addition, the levels of interferon alpha given to participants was much higher than would naturally be produced in the body – and those with persistent fatigue were not diagnosed with CFS. 
 
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 Michael Sharpe, professor of psychological medicine at the University of Oxford, said the study added another piece to the puzzle about what might kick off CFS. “It does seem that something to do with the immune system may be a triggering event, [but] it doesn’t actually tell us why, when that trigger seems to have gone away, the person stays fatigued,” he said. 
 
 Sharpe acknowledged the study did not shed light on how to treat established cases of CFS. “it may give us some clue down the line,” he said. “If the thing is triggered by an abnormal or excessive immune response, if we could find a way to reduce that immune response, we might stop incident cases.” 
 
 Dr Charles Shepherd, medical advisor at the ME Association, welcomed the study. “It adds to the growing weight of scientific evidence which indicates that the body’s immune system is playing an important role in the causation of CFS.”
– A small new study offers an intriguing clue about the baffling ailment known as chronic fatigue syndrome. Researchers in the UK say CFS, also known by its more scientific name of myalgic encephalomyelitis, appears to be triggered by an overactive immune system, reports the Guardian. Those who have CFS—including Seabiscuit and Unbroken author Laura Hillenbrand—suffer not just debilitating fatigue, but headaches, nausea, vertigo, and other symptoms that leave them unable to complete even the most basic tasks. The study suggests that sufferers may have an immune system that is genetically predisposed to go into hyper-drive when a virus or infection shows up, reports CNN. When it does, the cascade of debilitating—and easily misdiagnosed—symptoms begins. If the researchers are right, it could be a big first step on a poorly understood ailment. "This is a light in the fog, a direction of travel," says King's College London researcher Carmine Pariante, per the BBC. "Although screening is a long way off, our results are the first step in identifying those at risk and catching the illness in its crucial early stages." The study involved 55 people with hepatitis C who were given the standard treatment of the drug interferon-alpha. This treatment typically produces symptoms consistent with CFS, and the researchers measured levels of a protein linked to inflammation in participants' blood before, during, and afterward. Eighteen people had a particularly strong immune reaction to the treatment—including fatigue—and they also had higher levels of the suspect protein before the treatment began.