A new study found an association between chronic fatigue syndrome and variations in several immune system proteins, whose concentrations in the blood correspond with the severity of the disease. The findings were published July 31 in the journal Proceedings of the National Academy of Sciences.
Chronic fatigue syndrome, also known as ME/CFS (myalgic encephalomyelitis/ chronic fatigue syndrome) is a disease that has puzzled scientists for decades.
It’s characterized by an overwhelming fatigue that is not improved by rest, according to the Centers for Disease Control and Prevention. The CDC estimates that about 836,000 Americans suffer from ME/CFS, while the researchers estimate that more than 1 million people have ME/CFS. There’s no known cure or cause for the disease.
Researchers found 17 proteins associated with severity of ME/CFS
A group of researchers from Stanford University School of Medicine found that ME/CFS is associated with variations in 17 immune-system cytokines (proteins). Their findings prove that inflammation is a significant factor linked to the disease.
According to the researchers, three of every four chronic fatigue syndrome patients are women, for some unknown reason. The disease usually affects adolescents between the ages of 15 and 20 and adults between the ages of 30 and 35. ME/CFS often persists for decades, said the researchers.
Jose Montoya, professor of infectious diseases and lead author of the study, noted that ME/CFS could turn a life of productivity into one of desolation and dependency. Montoya explained that some people spontaneously recover during the first year, but rarely after the disease has persisted more than five years.
“There’s been a great deal of controversy and confusion surrounding ME/CFS – even whether it is an actual disease,” said Mark Davis, professor of immunology and microbiology and director of Stanford’s Institute for Immunity, Transplantation, and Infection, according to a statement from the university. “Our findings show clearly that it’s an inflammatory disease and provide a solid basis for a diagnostic blood test.”
The CDC says the “core” symptoms in people with ME/CFS include: greatly lowered ability to do activities that were common before the disease, worsening of ME/CFS symptoms after mental or physical activity that would not have caused an issue before, and sleep problems. Plus, the CDC adds that two other symptoms are required to make a proper diagnosis: problems with thinking and memory and worsening of symptoms while standing or sitting upright.
‘I have seen the horrors of this disease.’
Montoya added that some patients experience flu-like symptoms, which are quite common in inflammation-driven diseases. However, he noted that because symptoms can be so diffuse –sometimes as mental impairment or “brain fog,” sometimes as heart problems, or indigestion, diarrhea, muscle pain and so forth– the disease often goes undiagnosed.
“I have seen the horrors of this disease, multiplied by hundreds of patients,” said Montoya. “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.”
The researchers noted that even though some antivirals, anti-inflammatories and immune-modulating drugs have led to some improvement in certain cases, no scientist has identified the pathogenic agent responsible for triggering ME/CFS.
To tackle the problem, Montoya called on Davis, and together they created the Humane Immune Monitoring Center – a center equipped to study gene variations and activity levels, blood concentrations of scores of immune proteins, frequencies of immune cell types, and more.
Findings have important implications for the study of chronic fatigue syndrome
In the center, the scientists analyzed blood samples from 192 of Montoya’s patients –whose average duration of symptoms was about ten years– along with 392 healthy control subjects. The median age of all patients (including control subjects) was about 50.
The scientists took into account patient’s condition severity and duration. They found that particular cytokine levels were lower in patients with less severe forms of ME/CFS than in the control patients, but were elevated in ME/CFS patients with severe forms of the ailment.
The researchers compared the results between the patients and the control subjects and found that only two of the 51 cytokines they measured showed alterations. Then, they found that blood concentration in 17 of the cytokines tracked the severity of the disease. Thirteen of those cytokines are proinflammatory, they noted.
A cytokine known as TGF-beta was one of those 17 proteins. Montoya noted that chronic fatigue syndrome patients usually have a higher than average incidence of lymphoma, and he believes that TGF-beta’s elevation in these patients could be the link.
Overall, the findings hold implications for the study of the mysterious disease. The researchers believe the study could help with clinical trials testing immunomodulatory drugs’ as ME/CFS therapies.
“For decades, the ‘case vs. healthy controls’ study design has served well to advance our understanding of many diseases,” said Montoya. “However, it’s possible that for certain pathologies in humans, analysis by disease severity or duration would be likely to provide further insights.”
Source: Stanford Medicine News Center