THE multiple sclerosis is a chronic disease that damages the central nervous system and affects approximately 2.5 million people in the world, 770,000 of them in Europe. Although the underlying cause of this disease is not known at this time, a study published this week inside Science shows the main suspect: the Epstein Barr virus.

The work was carried out during a period of 20 years with the data of more than ten million military of the US, 955 of whom were diagnosed with multiple sclerosis during the service.

The authors found that the risk of developing multiple sclerosis in individuals negative for the Epstein-Barr virus increased 32-fold after infection.

The authors, scientists from Harvard University, found that the risk of developing this type of sclerosis in individuals who are negative for the Epstein-Barr virus – a member of the herpes virus family and the main cause of mononucleosis or kissing disease– multiplied by 32 after infection.

For several years, several research teams have analyzed the hypothesis that this virus causes this disease, but “this is the first study that provides convincing evidence of causality,” he says. Alberto Ascherio, from the Harvard T.H. Chan School of Public Health. “The results cannot be explained by any known risk factors and suggest that this virus is behind the origin of the disease.”

The scientist considers it “a big step, because it suggests that most cases of multiple sclerosis can be prevented by stopping the Epstein-Barr virus infection. Addressing him directly could lead to the discovery of a cure for this pathology.”

To determine the Connection between the two, the researchers analyzed serum samples taken every two years from the military. Thus, they found that the risk of suffering from multiple sclerosis multiplied by 32 after infection with Epstein-Barr, but did not change after infection with other viruses.

This work is a big step forward because it suggests that most cases of MS can be prevented by stopping the Epstein-Barr virus infection. Addressing him directly could lead to the discovery of a cure for this pathology.

Alberto Ascherio, author

In fact, serum levels of the neurofilament light chain, a biomarker of nerve degeneration typical of multiple sclerosis, only increased after herpesvirus infection.

No proven causal relationship

However, most people infected with this common virus do not develop multiple sclerosis, and the causality of this disease in humans cannot be directly demonstrated at this time.

that explains Daniel Davis, Professor of Immunology at Manchester University (UK): “More than 9 out of 10 people are infected with this virus worldwide, usually in childhood, and only very rarely does a problem occur.”

“We already knew that this virus increases the risk of some types of Cancer, and now that it can also be a factor in multiple sclerosis, although it’s important to note that most people who have the virus don’t have complications,” he adds.

However, most people infected with this common virus do not develop multiple sclerosis and it is not possible to directly demonstrate causality of this disease in humans at this time.

“More importantly, we don’t know why only a small fraction of people infected with this virus develop the disease. There must be other factors involved,” Davis continues. “The value of this discovery is not an immediate cure or medical treatment, but a breakthrough in Understanding multiple sclerosis”.

For the authors, “Establishing a causal relationship between the virus and the disease has been difficult. The Epstein-Barr virus infects approximately 95% of adults, while multiple sclerosis is relatively rare and the onset of symptoms begins about ten years after the viral infection.

Ascherio explained that the delay between infection and the onset of the disease “may be due to the fact that symptoms are not detected in the early stages and to the evolutionary relationship of this virus with the host’s immune system, which is repeatedly stimulated each time.” than the latent virus reactive.

Attack the virus to stop the disease

Currently, one of the most effective treatments for multiple sclerosis is anti-CD20 monoclonal antibodies. However, the researchers emphasize that attacking the virus can have major advantages over therapies based on these antibodies, which need to be given by intravenous infusion and can increase the risk of infections.

While there is currently no way to effectively prevent or treat Epstein-Barr virus infection, a vaccine against him or attack him with antiviral drugs specific “could, ultimately, prevent or cure multiple sclerosis”, concludes the expert.


Kjetil Bjornevik et al.: Longitudinal analysis reveals a high prevalence of the Epstein-Barr virus associated with multiple sclerosis. Science.


Rights: Creative Commons.



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