The Epstein-Barr Virus - Could it be Causing Neuroinflammation in ME/CFS?
EBV has been a virus of interest since almost day one in chronic fatigue syndrome (ME/CFS). In fact, at one point, EBV was such a hot topic that ME/CFS was called for a time "chronic Epstein-Barr virus" disease.
While studies have generally failed to find evidence of EBV reactivation, EBV has never fallen out of the picture with ME/CFS and for good reason. For one, it’s entirely possible that researchers were looking in the wrong place to determine if EBV is an issue in this disease. For another, EBV infection in adolescence or later and the infectious mononucleosis (glandular fever) it produces, is a common trigger in ME/CFS, and is a proven risk factor for multiple sclerosis.Besides ME/CFS, researchers are continuing to assess the role EBV may play in many serious illnesses including multiple sclerosis (MS), systemic lupus erythematosus (SLE), Guillain-Barre Syndrome, several cancers, rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), inflammatory bowel disease (IBD), celiac disease, schizophrenia, and others.Neuroinflammation, of course, is a hot, hot (pun intended) topic in both ME/CFS and fibromyalgia. Recent studies suggest neuroinflammation is present in both diseases and major studies are underway to validate that finding.Nobody until now, though has attempted to complete the circle, and bring that "original gangster" in ME/CFS - Epstein Barr Virus - and the new guy in town – neuroinflammation – together. Could EBV be causing or contributing to the neuroinflammation present in the disease?
Some History
Over 10 years of work by an Ohio State University team lead by Maria Ariza and Marshall Williams has been turning the EBV question in ME/CFS on its head. High levels of EBV, they believe, are not the problem in ME/CFS at all. In fact, their studies suggest that EBV may be at its most dangerous in ME/CFS not when it reactivates - but when it fails to reactivate properly.
By the time the impaired immune systems of people with ME/CFS have started knocking down EBV's attempt at reactivation, the bug has already produced a potentially pathogenic protein called dUTPase. The Ohio State University researchers believe this protein may be wreaking havoc in a large subset of people with ME/CFS.With the NIH supporting them every step of the way - their continuing grant on dUTPase is now in its 9th year - the evidence that this protein is contributing to ME/CFS (and other diseases) has continued to build.In 2012, the group found evidence that the immune systems of people in a large subset of ME/CFS patients were indeed battling this protein. Just a year later they showed that even when viral loads of EBV were low, dUTPase could still be triggering a significant pro-inflammatory response. That finding suggested that failed prior attempts to link EBV reactivation to ME/CFS were barking up the wrong tree.Two years later, they demonstrated that dUTPase was able to make its way into exosomes (now a major topic of interest in ME/CFS), cross the blood-brain barrier, produce major immune effects, and perhaps even promote further EBV infections.Then a 2017 study added another herpesvirus long suspected in ME/CFS - HHV-6 - to the mix. That study found antibodies to dUTPases produced by both EBV and HHV-6 in almost fifty percent of the ME/CFS patients. That suggested that the two herpesviruses might even be reactivating each other - a feature found in some very immune suppressed states including organ transplant patients and drug induced hypersensitivity syndrome.
Then again, really significant immune suppression in ME/CFS may not be a surprise. Up to 75% of ME/CFS patients were found to have low numbers of the B-cells designed to keep EBV in check in a recent study.If the immune system wasn't having enough trouble, in 2017 the first evidence of an autoimmune process involving EBV dUTPase was found in ME/CFS. Autoantibodies to the human dUTPases (humans produce a dUTPase as well) were found in ME/CFS - at much higher levels than in healthy controls (39% vs. 5%). That suggested that the immune response to EBV and HHV-6 dUTPase may have gone awry in some people with ME/CFS. Their bodies were now attacking their own human dUTPase.
The 2019 Study
In the present study we provide further evidence…. (that) dUTPase protein…could contribute to the development of a neuroinflammatory microenvironment in the brain(s) (of a subset of ME/CFS patients.) The authors
Epstein-Barr Virus dUTPase Induces Neuroinflammatory Mediators: Implications for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Marshall V. Williams PhD; Brandon Cox ; William P. Lafuse PhD; and Maria Eugenia Ariza, PhD. Clinical Therapeutics March 2019In 2019, the team took another step. In an earlier study they'd demonstrated that the EBV dUTPase protein could be causing or contributing to the symptoms present in ME/CFS. Since many of these symptoms can be produced by the brain, they next asked if the enzyme could be affecting the integrity of the blood-brain barrier (BBB) and other aspects of neuroinflammation.There's a pretty good reason to believe this might be the case. EBV, after all, has been associated with some pretty nasty neurological diseases. The virus loves to hang out in nerve cells and astrocytes, is a risk factor for M.S. and has, in fact, been found scattered throughout the astrocytes and microglial cells in MS patients' brains.The Ohio State University researchers plopped the dUTPase protein into a variety of cells and then determined how it affected the expression of genes that play an important role in maintaining the blood brain barrier (BBB) and the functioning of various brain cells (cerebral microvascular endothelial cells, astrocytes, microglia cells).The big bug's dUTPase protein turned out to be quite adept at tweaking genes and proteins associated with the BBB and neuroinflammation. It turned on 12 of 15 genes and 32 of the 100 proteins examined in vitro (in the lab) and 34 of the 84 genes examined in mice.The fact that these genes play a role in BBB integrity/function, fatigue, pain synapses and their functioning as well as tryptophan, dopamine, and serotonin metabolism suggested that this enzyme, in or out of the brain, could conceivably cause widespread problems.How the Blood-Brain Barrier Works https://www.youtube.com/watch?v=e9sN9gOEdG4 All in all, the protein appeared to be doing its best to find a way to get EBV into the brain. That's perhaps not a surprise given how much EBV loves to hang out in neurons. As EBV dUTPase was down regulating the expression of genes dedicated to producing a tight BBB it was "strongly" inducing the expression of two cytokines (IL-6 and IL-1β) known to disrupt The BBB.If EBV dUTPase gets inside the brain, it seems almost guaranteed to cause neuroinflammation. Studies indicate it can trigger microglial cells and astrocytes (star-shaped immune cells in the brain) to produce potent pro-inflammatory cytokines (IL-6, IL-1β and TNF-α). It also prompts astrocytes to produce a substance (PTGS2/COX-2) associated with neuroninflammatory toxicity. Plus it's able to alter the expression of genes associated with pain (GPR8451 and GCH152) and fatigue (TBC1D153) to boot.In mice, it altered the expression of genes associated with cognition (synaptic plasticity, learning and memory). One of the more intriguing findings, given the possible disruption of the kynurenine pathway in ME/CFS, was the protein's potential to increase synthesis of a potent neurotoxin called quinolinic acid. Genes associated with the metabolism of two of the major neurotransmitters in the brain, dopamine, and serotonin, were also affected.
All in all, EBV dUTPase is not a protein anyone wants hanging out in their head. It is, however, a protein that could potentially produce a lot of the problems found in ME/CFS. This study demonstrated that the protein appears to have the capability to make its way to ME/CFS patient's brains. Determining if it has will take further investigations, however.It should be noted that the protein and its antibodies (or the autoantibodies to the human dUTPase) are not found in everyone with ME/CFS but the potential subset - ranging from 30% to 60% of those tested so far, is pretty darn large.Plus, the virus is heavily implicated in the stress response. If you feel like your nervous system is over-reacting to, well, anything (or everything), EBV and this protein could be a factor. Of all the viruses, EBV and the herpesviruses love most to come out and play when one's system is stressed.In fact, Ron Glaser, one of the initiators of the EBV dUTPase research effort, demonstrated back in 1991 that EBV thrives in situations of psychological stress. Given the enormous stress people with ME/CFS are under, and the affects the illness has on both axes of the stress response, it makes sense that the virus might be continually trying to reactivate - and spilling it's toxic protein into the bloodstreams of some people with this disease.
A Good-bye to a Pioneer
Ron Glaser was something of a legend in his own time. With his doctorate in pathology, his EBV citations alone total over 100. All told he published over 300 papers. Glaser co-founded Institute for Behavioral Medicine Research, which under his leadership brought in over 140 million in grant money over 20 years. At one point he was one of the world's most cited authors.His memorials mention his impact on the psychoneuroimmunological (PNI) field, his enthusiasm, (and the red and white Corvette he loved). What they don't mention is that this leader also devoted time to a much neglected field called chronic fatigue syndrome. Glaser, in fact, took the time out of his busy schedule to sit on the now disbanded federal advisory committee for ME/CFS (CFSAC).I vividly remember talking to him. He was not a man to mince words. An accomplished researcher with a long history of grant success, Glaser was first shocked, and then very angry at the rejections piling up for his ME/CFS grant applications. He just couldn't understand it. Never in his decades of work had he experienced such a thing.Stating, ironically, he couldn't stand the stress (he did look like he was about to burst a blood vessel), he eventually moved on, but not before making his experiences perfectly clear to the federal advisory committee and everyone around him.Glaser was not happy at not being able to work more in ME/CFS, but the work he did did not go for naught. Glaser first published on EBV dUTPase in 1985 and on EBV and ME/CFS in 1988 and his work lives on in Ariza and William's studies on ME/CFS today. Check out a memorium to Ron here.
Marshall Williams - On the Continuing Hunt for EBV dUTPase in ME/CFS
What about the connection between this protein and the presence of infectious mononucleosis/glandular fever in ME/CFS? Do we have any idea if the enzyme is more likely to be found in people who's disease was triggered by IM or who had an acute, flu-like onset?That is an excellent question. We are in the process of trying to obtain longitudinal serum samples from an IM cohort who developed CFS as well as age matched patients who had IM but never developed CFS. Hopefully, that may address this question.
This study demonstrated that this enzyme has the potential to disrupt the BBB and enter the brain - and as added bonus - perhaps helps get EBV into the brain. Is there any way to tell if this has actually happened in ME/CFS?Not really at this point but maybe in the future. Screening CSF from ME/CFS patients for antibodies to the EBV-dUTPase or HHV-6 dUTPase might suggest potentially the presence of these viruses in the brain.Exosome research is heating up in ME/CFS. Some anecdotal reports show that exosomes in the blood may be affecting energy metabolism and other functions. Could herpesvirus dUTPases be involved? Is there any more information on exosomes and EBV dUTPases?We have not looked at energy metabolism but there are some reports in the literature that some herpesviruses including EBV and HHV-6 alter mitochondrial function. There is information concerning EBV products in exosomes but most of these have focused on proteins/microRNAs involved with latency.What is next for your team? We are in the process of submitting a manuscript detailing a mechanism(s) by which the EBV-dUTPase and to a lesser extent the HHV-6 dUTPase alter germinal center function, which could contribute to autoimmunity in CFS patients. We will be continuing these studies as well as those regarding neuroinflammation. (B-cells manufacture autoantibodies in the germinal centers found in the lymph nodes and spleen)