Stanford study finds blood biomarkers linked to chronic fatigue syndrome
Chronic fatigue syndrome (CFS), or myalgic encephalomyelitis (ME) as many sufferers prefer it called, is still one of the more mysterious ailments physicians grapple with. The disease has no known cure, is difficult to diagnose, and still to this day is debated by some as being more a psychological condition than a physical one. Researchers at Stanford University have recently made a breakthrough in pinning down the physiological origins of this mysterious malady, which may pave the way for a blood test that could diagnose it.
The disease was only officially classified as chronic fatigue syndrome in the late 1980s, but for much of the 20th century the symptoms were recognized by doctors as an unknown illness. The condition manifests in a variety of symptoms that can often differ from patient to patient. Severe fatigue, muscle pain, allergies, irritable bowel syndrome, depression and impaired memory are just some of the symptoms used to diagnose ME/CFS.
Due to diagnostic challenges it is thought that anywhere from one to two million Americans have the disease. The problem physicians face in trying to diagnose patients suffering it is that there are no biological markers to identify the condition. This means diagnosis tends to be one of exclusion, belatedly offered when other conditions have been ruled out.
"I have seen the horrors of this disease, multiplied by hundreds of patients," says Jose Montoya, lead author on the new study. "It's been observed and talked about for 35 years now, sometimes with the onus of being described as a psychological condition. But chronic fatigue syndrome is by no means a figment of the imagination. This is real."
Determined to pin down a pathogenic origin to the disease, Montoya looked at its possible inflammatory sources. Antiviral and anti-inflammatory drugs have, in the past, demonstrated sporadic effectiveness in managing ME/CFS, so the team turned to analyzing immune proteins and cell types found in the blood samples of affected patients.
Previous studies had identified that abnormalities in the regulation of a family of proteins called cytokines tended to correspond with the disease. The problem was that some cytokine levels in mild cases of ME/CFS were identified as low, while those same levels were seen to be elevated in patients with severe cases.
The research moved to more accurately identify those specific proteins and found the concentrations of 17 different cytokines rose in accordance with the severity of a patient's ME/CFS.
One of the more interesting findings of the research was the discovery that leptin, a cytokine secreted by fat tissue, was one of the markers that correlated with the disease's severity. Leptin is a known pro-inflammatory protein and found more prominently in women's blood than men's. This could offer a clue as to why ME/CFS is found to occur more often in women than in men.
The research doesn't explore whether these cytokine levels actually cause the symptoms seen in the disease, but it does offer scientists a tantalizing pathway towards a clearer biological understanding of the mysterious illness. The study's senior author, Mark Davis, is determined the revelatory research will once and for all put an end to debate over whether the disease is real or psychologically based.
"There's been a great deal of controversy and confusion surrounding ME/CFS – even whether it is an actual disease," said Davis. "Our findings show clearly that it's an inflammatory disease and provide a solid basis for a diagnostic blood test."
The team's research was published in the journal Proceedings of the National Academy of Sciences.
Source: Stanford Medicine