Emerging evidence suggests that autoimmunity plays a role in postinfectious myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and that targeting autoantibodies could be a promising treatment approach.
Dr. Carmen Scheibenbogen
The same may also apply to many cases of “long COVID,” in which many of the symptoms overlap with those of ME/CFS, Carmen Scheibenbogen, MD, professor of clinical immunology and director of the Institute for Medical Immunology, Charité University Medicine, Berlin, said during the annual meeting of the International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.
Several groups, including Dr. Scheibenbogen’s, have reported finding autoantibodies against neurotransmitter receptor antigens in people with ME/CFS. And, in a paper published in the Journal of Clinical Medicine the day that Dr. Scheibenbogen spoke at the meeting, her team reported significant correlations between autoantibodies to vasoregulative G-protein–coupled receptors and symptom severity, autonomic dysfunction, and disability among 116 patients with infection-triggered ME/CFS who were diagnosed using the symptom-based 2003 Canadian consensus criteria.
People with ME/CFS are also more likely to have genetic risk factors associated with autoimmunity and personal and/or family histories of autoimmune conditions. And, clinical trials have demonstrated early success with various immunomodulatory treatments in subsets of people with ME/CFS, including endoxan, rituximab, and immunoadsorption.
“We have evidence that ME/CFS is an autoantibody-mediated disease, and we have evidence that autoantibody targeting is effective in this disease. So far ... we have few and underfinanced clinical studies, but the good news is we have promising emerging treatment options,” Dr. Scheibenbogen said.
Dr. Anthony L. Komaroff
Asked to comment, ME/CFS expert Anthony L. Komaroff, MD, of Brigham and Women’s Hospital and Harvard Medical School, both in Boston, said: “There is already strong evidence that there are autoantibodies in ME/CFS. Dr. Scheibenbogen’s work is the latest and employs the latest technology. ... I would bet that autoantibodies to neural targets are likely to cause some of the symptoms of ME/CFS and some of the symptoms of long COVID.”
However, he cautioned, “that has not been proven, and even if it were proven you would have to demonstrate that treatments based on that theory worked.”
Dr. Komaroff said he views autoimmunity as a likely component of the ME/CFS spectrum, but not the only one. “My current view of this illness is that there’s a final common pathway in the brain that leads to the symptoms of the illness. But that final common pathway can be triggered by a variety of different things, one of which could be autoantibodies while another could be infection or inflammation in the brain.”
Emerging evidence points to autoimmunity
Dr. Scheibenbogen summarized the work published in this area over the past few years by her group and others.
In a comparison of ME/CFS patients with 201 healthy controls, significant associations were seen with two specific autoimmunity-related risk alleles only in the ME/CFS patients who reported acute onset of disease with an infection but not in those with ME/CFS without infection-triggered onset or the controls. Both genes play roles in regulating B- and T-cell activation.
Another recent study found associations with ME/CFS and major histocompatibility complex class II molecules, a typical feature of autoimmune diseases, in a comparison between 426 adult Norwegian ME/CFS patients who were diagnosed with the Canadian consensus criteria and 4,511 healthy, ethnically matched controls.
In a 2020 paper, Dr. Scheibenbogen and pharmacologist Klaus Wirth presented a “unifying hypothesis” of ME/CFS pathophysiology based on the finding of elevations in autoantibodies against beta2-adrenergic receptors and muscarinic acetylcholine receptors in some individuals with the condition. Since both of those receptors are important vasodilators, their functional disturbance would be expected to cause vasoconstriction and hypoxemia, which would explain many of the symptoms of ME/CFS. This mechanism would align with other findings of muscular and cerebral hypoperfusion that correlate with fatigue, particularly post exertion, as well as metabolic changes that are in line with the concepts of hypoxemia and ischemia.
Further evidence for vascular dysfunction in ME/CFS came from her group’s study finding evidence of peripheral endothelial dysfunction that was associated with symptom severity in 35 adult patients. “Vasoconstriction, hypovolemia, and release of vasoactive and algesic mediators is probably a key pathomechanism of the disease,” Dr. Scheibenbogen said.