In order to implement a disease prevention strategy, it is necessary to know its causes and risk factors. “With regard to multiple sclerosis, we now have a track of risk factor, which is infection by the Epstein Barr virus responsible for infectious mononucleosis” informs Professor Jean Pelletier, President of the medical and scientific committee of the ARSEP foundation (foundation for aid in research on multiple sclerosis). Several studies, including a very important one conducted in the United States, show that, overall, you do not develop multiple sclerosis if you have not been infected with the Epstein-Barr virus (EBV), a herpes virus which infects more than 90% of the French population.
Multiple sclerosis would thus be a rare complication of this infection in people with a genetic susceptibility that would make the body more fragile. “200 genes are thought to be involved, some of which are found in many other autoimmune diseases such as diabetes or rheumatoid arthritis,” says Professor Pelletier. It remains to be seen when contracting the Epstein-Barr virus poses the greatest risk of developing the disease. It seems that the risk is greater if one develops mononucleosis and not an infection without symptoms and when mononucleosis occurs in adolescence.
Prevent multiple sclerosis with an EBV vaccine
“Since EBV infection is the most important risk factor for triggering multiple sclerosis, we can extrapolate by saying that if we prevent the fact of contracting the Epstein-Barr virus, we could eliminate multiple sclerosis or at least reduce its frequency” explains Professor Pelletier. This would require the development of a vaccine against this virus. EBV vaccines are currently being tested in clinical trials.
Then the question would arise: who to vaccinate, at what age? “If we vaccinate young children with an RNA virus, will this vaccine be effective for long enough, or will it be necessary to revaccinate regularly? asks our expert, who adds that it might be more relevant to vaccinate people who have a genetic susceptibility and are therefore more at risk of developing multiple sclerosis after an EBV infection.
Act on the Epstein Barr virus to limit the progression of the disease
The EBV track is interesting for considering disease prevention, but could also be used to prevent flare-ups in people who have already developed the disease. “Once this virus has entered our body, it remains in our B lymphocytes in a latent state. If it reactivates, can this explain flare-ups? explains Professor Pelletier. If it is proven that the EBV virus has an effect on the progression of the disease, it would be useful to develop antivirals to act on this virus and avoid its involvement in the progression of the disease.
Sources:
Bjornevik, K., Münz, C., Cohen, JI et al. Epstein-Barr virus as a leading cause of multiple sclerosis: mechanisms and implications. Nat Rev Neurol 19, 160-171 (2023)
Francesca Aloisi, Gavin Giovannoni, Marco Salvetti, Epstein-Barr virus as a cause of multiple sclerosis: opportunities for prevention and therapy, Lancet Neurol 2023; 22: 338-49
