The debilitating condition once derided as "yuppie flu" is a genuine illness, researchers say.
Controversy has raged for nearly 30 years as to whether the symptoms of chronic fatigue syndrome are real or all in the mind.
Now a study shows the condition, also known as myalgic encephalomyelitis or ME, does trigger a distinctive immune response in the body.
The discovery paves the way for treatments that, given early enough, could prevent years of ill health.
It should also help ease the stigma that has led to sufferers being dismissed as malingerers who imagine their symptoms.
ME affects some 250,000 Britons and is more common in women than men. It was called `yuppie flu’ in the 1980s because sufferers tend to be aged between 20 and 40 and the illness was most frequently seen among professional people.
Symptoms include extreme physical and mental fatigue and painful limbs. The condition can also affect memory, concentration and digestion, with some sufferers left so weak that they lose their job or become bed or wheelchair-bound. But with the cause unclear, scepticism has remained as to whether it is a physical illness or merely psychological.
The researchers, from Columbia University in New York, analysed hundreds of blood samples taken from ME patients and healthy people. The blood from those with ME showed a distinct `chemical signature’.
It had higher levels of various compounds released by the immune system to defend the body against infection. The link with an immune protein, interferon gamma, was particularly strong, the journal Science Advances reports.
Interferon gamma is blamed for the extreme tiredness that follows some viral infections and has also been linked to problems with memory.
The finding may help researchers develop the first diagnostic test for ME. It also raises hope of better treatments. Drugs that lower levels of some of the immune proteins already exist.
`This study delivers what has eluded us for so long: unequivocal evidence of immunological dysfunction in ME and diagnostic biomarkers for disease,’ said researcher Dr Ian Lipkin.
Lead author Dr Mady Hornig said: `We now have evidence confirming what millions with this disease already know, that ME isn’t psychological.’
However, the work is still preliminary and many questions remain to be answered, including why the chemical markers show up only in the blood of patients in the relatively early stages of ME.
Dr Hornig’s team is now looking for signs of the infection that triggered the immune response. Scientists have long thought a virus is to blame but have failed to find the culprit.
Dr Neil Abbot, of ME Research UK said: `A biological signature or thumbprint for ME is the holy grail — it’s what we all want to see. If the immune changes reported in the study can help, it would be a great step forward.’
The finding that the chemical signature is seen only in the first stages of ME shows the importance of early diagnosis and treatment, he added.
Sonya Chowdhury, of Action for ME, said the work `could have significant implications for quicker diagnosis and improved treatments’.
But some experts cautioned that the findings are preliminary and that ME research has been `bedevilled with false dawns’ for decades.
— Daily Mail
