Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM) have overlapping neurologic symptoms — particularly profound fatigue. The similarity between these two conditions has led to the question of whether they are indeed distinct central nervous system (CNS) entities, or whether they exist along a spectrum and are actually two different manifestations of the same disease process.
A new study utilized a novel methodology — unbiased quantitative mass spectrometry-based proteomics — to investigate this question by analyzing cerebrospinal fluid (CSF) in a group of patients with ME/CFS and another group of patients diagnosed with both ME/CFS and FM.
Close to 2,100 proteins were identified, of which nearly 1,800 were common to both conditions.
“ME/CFS and fibromyalgia do not appear to be distinct entities, with respect to their cerebrospinal fluid proteins,” lead author Steven Schutzer, MD, professor of medicine, Rutgers New Jersey School of Medicine, told this news organization.
“Work is underway to solve the multiple mysteries of ME/CFS, fibromyalgia, and other neurologic-associated diseases,” he continued. “We have further affirmed that we have a precise objective discovery tool in our hands. Collectively studying multiple diseases brings clarity to each individual disease.”
The study was published in the December 2023 issue of Annals of Medicine.
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“ME/CFS is characterized by disabling fatigue, and FM is an illness characterized by body-wide pain,” Dr. Schutzer said. These “medically unexplained” illnesses often coexist by current definitions, and the overlap between them has suggested that they may be part of the “same illness spectrum.”
But co-investigator Benjamin Natelson, MD, professor of neurology and director of the Pain and Fatigue Study Center, Mount Sinai, New York, and others found in previous research that there are distinct differences between the conditions, raising the possibility that there may be different pathophysiological processes.
“The physicians and scientists on our team have had longstanding interest in studying neurologic diseases with cutting-edge tools such as mass spectrometry applied to CSF,” Dr. Schutzer said. “We have had success using this message to distinguish diseases such as ME/CFS from post-treatment Lyme disease, multiple sclerosis, and healthy normal people.”
Dr. Schutzer explained that Dr. Natelson had acquired CSF samples from “well-characterized [ME/CFS] patients and controls.”
Since the cause of ME/CFS is “unknown,” it seemed “ripe to investigate it further with the discovery tool of mass spectrometry” by harnessing the “most advanced equipment in the country at the pacific Northwest National Laboratory, which is part of the US Department of Energy.”
Dr. Schutzer noted that it was the “merger of different clinical and laboratory expertise” that enabled them to address whether ME/CFS and FM are two distinct disease processes.
The choice of analyzing CSF is that it’s the fluid closest to the brain, he added. “A lot of people have studied ME/CFS peripherally because they don’t have access to spinal fluid or it’s easier to look peripherally in the blood, but that doesn’t mean that the blood is where the real ‘action’ is occurring.”
The researchers compared the CSF of 15 patients with ME/CFS only to 15 patients with ME/CFS+FM using mass spectrometry-based proteomics, which they had employed in previous research to see whether ME/CFS was distinct from persistent neurologic Lyme disease syndrome.
This technology has become the “method of choice and discovery tool to rapidly uncover protein biomarkers that can distinguish one disease from another,” the authors stated.
In particular, in unbiased quantitative mass spectrometry-based proteomics, the researchers do not have to know in advance what’s in a sample before studying it, Dr. Schutzer explained.