Two recent studies have found evidence of multiple sclerosis resulting from an Epstein-Barr virus (EBV) infection.
Earlier this month, researchers at Harvard University conducted a massive study on approximately 10 million U.S. military personnel over a period of 20 years. They hypothesized that an Epstein-Barr virus (EBV) infection most likely results in the development of multiple sclerosis (MS). Therefore, researchers analyzed soldiers’ serum samples for EBS antibodies. Over the course of the study, 955 of the participants developed multiple sclerosis.
Multiple Sclerosis is a chronic demyelinating disorder of the central nervous system. Immune-mediated destruction of the myelin sheath surrounding neurons results in muscle weakness, fatigue, and numbness. Although viral infections such as infectious mononucleosis, herpes virus, and EBV have often been thought to trigger the disease, causality has yet to be established. There is currently no cure for the disease. However, researchers are currently working on a vaccine for the disorder.
According to the study published in Science, soldiers with EBV antibodies had a 32-fold higher risk of MS. But the risk was unchanged after infection with other viruses, such as cytomegalovirus. Moreover, levels of a nerve degeneration biomarker commonly seen in MS also only increased after EBV infection.
The hypothesis that EBV causes MS has been investigated by our group and others for several years, but this is the first study providing compelling evidence of causality.
Professor Alberto Ascherio, senior study author
Although the exact mechanism remains unclear, the study points to EBV’s role in MS onset. Furthermore, it reveals that EBV-specific treatments can likely prevent or cure MS.
Stanford Study Further Confirms Link
Building on the Harvard study, researchers at Stanford Medicine have now finally identified how the virus triggers multiple sclerosis.
The team analyzed antibodies in the blood and spinal fluid samples of nine MS patients. They then tested their reactivity with EBV and other herpes viruses. Results showed several of the antibodies binding to EBV. Furthermore, the same antibody also bound with high affinity to a protein called GlialCAM. This particular protein is present in myelin sheaths and enables the transmission of nerve impulses. To confirm their results further, the researchers looked at a larger MS sample and found a high affinity to these proteins in 20 to 25% of blood samples.
EBV tricks the immune system into responding not only to the virus, but also to this critical component of the cells that make up the white matter in our brains.
Lawrence Steinman, study author
According to the study author, William Robinson, a part of the EBV protein mimics GlialCAM. Therefore, in case of an EBV infection, the immune system ends up attacking the virus as well as its own proteins present in the myelin sheath.
Reference:
Bjornevik, Kjetil, et al. “Longitudinal Analysis Reveals High Prevalence of Epstein-Barr Virus Associated with Multiple Sclerosis.” Science, vol. 375, no. 6578, 2022, pp. 296–301., doi:10.1126/science.abj8222.
Lanz, T.V., Brewer, R.C., Ho, P.P. et al. Clonally Expanded B Cells in Multiple Sclerosis Bind EBV EBNA1 and GlialCAM. Nature (2022). https://doi.org/10.1038/s41586-022-04432-7
