In an effort to find the cause of chronic fatigue syndrome, researchers have identified 17 immune molecules whose concentrations in patients’ blood correlate with disease severity.

Why it matters:

Chronic fatigue syndrome (CFS) is poorly understood and notoriously difficult to diagnose or treat, and some medical professionals question whether it is psychological or biological in nature. One area of research has been cytokines — molecules the immune system uses to communicate while combating foreign invaders in the body.

“For many years medical scientists have speculated that the symptoms of CFS might be caused by cytokines,” said Dr. Anthony Komaroff, a physician at Brigham and Women’s Hospital not involved in the study. “Past studies have shown high levels of many cytokines in people with CFS, but it was not clear that these high levels were causing symptoms.”

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The nitty-gritty:

Dr. Jose Montoya, an infectious disease specialist at Stanford University, and his colleagues looked at cytokines in the blood serum of 192 people with CFS and 392 healthy controls. They deployed a system called Luminex, which used a combination of microbeads filled with cytokine-capturing antibodies and lasers to pull out 51 different cytokines from serum samples and quantify how much of each cytokine was present.

Overall, people with CFS only had two cytokines that significantly differed in quantity compared to healthy controls. However, when researchers divided people with CFS into mild, moderate, and severe groups, they found that the levels of 17 cytokines increased with increasing severity of the disorder. Thirteen of these cytokines were proinflammatory, meaning they cause inflammation in the body. The results were published Monday in Proceedings of the National Academy of Sciences.

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“It’s giving us an idea about the type of inflammation that these patients are experiencing, so it validates the disease … it’s like, gosh, the patients were right all along,” explained Montoya.

But keep in mind:

The study established an association between proinflammatory cytokines and CFS, but not cause and effect: More research is needed to understand the relationship between the two.

You should know:

Researchers see this helping in two ways. Montoya and colleagues hope it will help other researchers develop CFS treatments that target these proinflammatory cytokines. They also think it could be a useful diagnostic test. Part of the team is now working on transforming the technique so it can be used to help diagnose CFS in a clinical setting.

What they’re saying:

Columbia University neuroimmunology specialist Dr. Mady Hornig, who wasn’t involved in the study, praised it for providing “critical support for a biologic basis in a disorder that is so often maligned as being psychological,” and highlighting the complexity of immune dysregulation that occurs in patients with CFS.

Komaroff said it “supports the theory that cytokines might be a cause of symptoms.”

The bottom line:

A number of proinflammatory cytokines correlate with CFS severity, but more research is needed to figure out if these cytokines cause symptoms, and how they can be used to develop better diagnostic and treatment techniques.