Those with chronic fatigue syndrome - now systemic exertion intolerance disease - vary in their immune systems http://www.nytimes.com/2015/02/28/health/chronic-fatigue-syndrome-study-findings-may-lead-to-diagnostic-tool.html …
Study on Chronic Fatigue May Help With Diagnoses
By DAVID TULLERFEB. 27, 2015
The immune systems of people with chronic fatigue syndrome differ from those of healthy people, and patients with recent diagnoses can be distinguished from those who have had the condition for longer, researchers reported on Friday.
The findings do not have immediate clinical applications for patients, experts said. But the biomarkers discovered by the scientists may eventually form the basis of the first diagnostic test for the illness.
“A biomarker has been the goal for much of the research for the last 15 years, so it’s really excellent that they have found something they consider significant,” said Dr. Birgitta Evengard, a professor of clinical microbiology at Umea University in Sweden and an expert on the illness.
The findings still need to be replicated in other labs with other groups of patients, cautioned Dr. Evengard, who was not involved in the research.
The study was published online in a new open-access journal called Science Advances, just two weeks after the Institute of Medicine proposed a new name for the illness — “systemic exertion intolerance disease” — and new diagnostic criteria to better identify patients. The authors of a report put out by the institute described the illness as a biological disorder and said the central symptom was “post-exertional malaise,” a sustained relapse after minimal activity.
Chronic fatigue syndrome is also called myalgic encephalomyelitis, which means “muscle pain with brain and spinal cord inflammation,” and is often referred to as ME/CFS. An estimated one million Americans may have the condition, and some are homebound for years.
For the study, the research team — which included scientists from Columbia, Stanford and Harvard — tested the blood of 298 patients with the syndrome, and 348 healthy people who served as a control group, for 51 cytokines, substances that function as messengers for the immune system. When the team compared all the patients with all the healthy controls, they found no significant differences between the two groups.
But after dividing the patients into two cohorts — those who had been sick for less than three years and those who had been sick longer — they found sharp differences. And both sets of patients were different from healthy controls.
Patients who had been ill for less than three years had “a prominent activation” of cytokines that influence inflammation in the body compared with other study subjects, the scientists found. Those sick for longer than three years exhibited dampened cytokine activity, which the researchers interpreted as a possible sign of premature immune-system aging.
“There are biological markers that can be detected in the blood soon after the onset of the disease, and this has very important diagnostic implications,” said Dr. Mady Hornig, an associate professor of epidemiology at Columbia University and lead author of the new study.
Most cases of ME/CFS occur after an acute viral infection. Some researchers have speculated that the infection, or an environmental exposure or other trauma, sets off an immune response that increases cytokine production. The immune system, however, does not return to normal functioning once the threat has passed.
The underlying cause of the syndrome is unknown, and current treatments generally aim for symptom relief. Some medications already in use affect the cytokines that were shown to be active in patients, Dr. Hornig said. Those drugs would be obvious candidates to test in clinical trials, she said.
The research team plans to publish data later this year on changes in individual cytokine profiles over time, tracking more closely how they fluctuate with the reported severity of symptoms and other factors, Dr. Hornig said.
A version of this article appears in print on February 28, 2015, on page A12 of the New York edition with the headline: Study on Chronic Fatigue May Help With Diagnoses.
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