New Evidence of Chronic Fatigue Syndrome’s Biological Roots

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Photo: Cath Riley/corbis

It’s been a good month for people with chronic fatigue syndrome, an often-misunderstood condition marked by feelings of listlessness and memory or concentration problems. A few weeks back, an Institute of Medicine committee urged the medical community to take the illness more seriously, outlining a new list of diagnostic symptoms. And today, a study published in Science Advance, led by Mady Hornig of Columbia University’s Mailman School of Public Health, identifies new evidence of the condition’s biological roots — findings that Hornig said could lead to better, earlier diagnoses of the condition.

Hornig and her team analyzed blood samples from 298 adults who had chronic fatigue syndrome and 348 who did not. (Patients were recruited from studies by the Chronic Fatigue Initiative and the National Institutes of Health.) Of those who had the condition, 52 had started experiencing symptoms in the past three years. And in these patients, Hornig told Science of Us, her team found “distinct immune signatures, differences in the immune molecules in the bloodstream, that could be detected through different laboratory tests.” 

Specifically, the researchers found higher levels of several different types of cytokines, a protein that triggers immune system response, when compared to both the healthy controls and those who’d had the disease for longer. “It appears that [chronic fatigue] patients are flush with cytokines until around the three-year mark, at which point the immune system shows evidence of exhaustion and cytokine levels drop,” Hornig said in the study’s press release. “Early diagnosis may provide unique opportunities for treatment that likely differ from those that would be appropriate in later phases of the illness.” It’s worth noting, however, that Dr. Theodore Ganiats of the University of California at San Diego, who served on the IOM committee, cautions that though these findings do appear to be statistically significant, they may not be clinically significant. (That is, not quite enough to make any difference in practical application.)

Still, Hornig said that these findings also suggest what may spark chronic fatigue syndrome — it could begin with an infection. “We know that most people with common disorders like infectious mononucleosis get better after a period of time,” she said. “But 5 to 10 percent don’t get better, and go on to have this chronic fatigue-like illness. And we know that a large subset of individuals [with chronic fatigue] begin their illness with a sore throat, swollen glands in the head and neck, a fever, malaise — kind of the types of things that you get when you have the flu, but it just doesn’t go away.”

Eventually, Hornig said, a simple blood test may be enough to diagnose the condition. It’s in the early days yet, but Hornig is now in the process of analyzing data from a long-term study of chronic fatigue syndrome patients. Soon, we may have a better idea of how the condition changes over time, along with some potential new ways to help patients cope.