MS and the Epstein-Barr virus
Published: 28 March 2022
The missing link?
Despite decades of research, the underlying cause of multiple sclerosis (MS) remains unknown,[1]making predicting and preventing this devastating disease near impossible. However, some interesting evidence has recently come to light that may be game changing for HCPs, current patients and future generations: what difference might one virus make?
We still don’t really know what causes MS. While several factors continue to be investigated, one that has recently been building a strong evidence base is a viral trigger.[1]
The Epstein-Barr virus (EBV), a common herpes virus that can cause mononucleosis and continues to live on in the body after infection, has in particular been a key suspect.[1][2]
With the ability to induce neuroinflammation and demyelination, and to promote proliferation, degeneration and necrosis of glial cells, EBV has been linked to the development of many nervous system diseases such as Alzheimer’s and Parkinson’s as well as MS.[3] However, there has been little in the way of direct evidence – until now.[4][5]
An experiment of nature[4]
In what they called an “experiment of nature”, Bjornevik et al. (2022) studied over 10 million US military personnel between 1993 and 2013. About 5% were negative for EBV when they started service and 955 people eventually developed MS.[4]
Of these 955 individuals, the authors further analysed 801 of whom they had appropriate blood samples, and compared them to controls without MS. They found some striking statistics:[4]
With a stronger link than any other known MS risk factor,[4] it seems likely that EBV could in some way be causing MS. The authors even measured antibodies against other human viruses but found no difference between groups.[4] So what is it about EBV?
The possible mechanisms behind it
Previous studies have shown that EBV-encoded proteins are involved in the development of MS, and EBV-specific antibodies are more common in patients than healthy controls.[3] In 2022, Lanz et al. (2022) found that 20–25% of MS patients had developed cross-reactive EBV EBNA1 and GlialCAM antibodies, an epitope that can exacerbate autoimmune demyelination. By providing a mechanistic link, their results could help guide the development of novel therapies.[5]
So, what does it all mean for you and your patients? Despite this recent evidence, EBV is, of course, an extremely common virus and therefore alone is insufficient for a diagnosis of MS. It’s likely that a combination with other factors leads to an increased risk.
However, this is a great clue in elucidating the mystery that is MS, and how to prevent and treat it. In the future, scientists might be looking at antivirals that target EBV, B-cell deletion therapies, and vaccines that prevent EBV infection thus potentially preventing many cases of MS before they even begin.
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Abbreviations
EBNA1=EBV nuclear antigen 1; EBV=Epstein-Barr virus; GlialCAM=glial cell adhesion molecule; HCP=healthcare professional; MS=multiple sclerosis.
