There is more evidence that one of the world’s most prevalent viruses may put some people on the path to developing multiple sclerosis.
Multiple sclerosis is a potentially disabling disease that occurs when cells of the immune system mistakenly attack the protective covering of nerve fibers, gradually destroying them.
The Epstein-Barr virus has long been suspected of a role in the development of multiple sclerosis. This link is difficult to prove because almost everyone becomes infected with the Epstein-Barr virus, usually in childhood or at a young age, but only a small proportion develop multiple sclerosis.
On Thursday, Harvard researchers reported on one of the largest studies supporting the Epstein-Barr theory.
They tracked blood samples held by more than 10 million people in the US military and found that the risk of multiple sclerosis increased 32-fold after an Epstein-Barr infection.
The military regularly gives blood tests to its members, and researchers tested samples stored from 1993 to 2013 for antibodies that signal a viral infection.
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Only 5.3% of new recruits showed no signs of Epstein-Barr when they joined the army. The researchers compared 801 cases of MS subsequently diagnosed over a 20-year period with 1,566 military personnel who had never had MS.
Only one of the MS patients had no evidence of Epstein-Barr virus prior to diagnosis. And despite intensive searches, the researchers found no evidence that other viral infections played a role.
The findings “strongly suggest” that Epstein-Barr infection is “a cause, not a consequence, of multiple sclerosis,” said study author Dr. Alberto Ascherio of the Harvard School of Public Health. T. H. Chana and colleagues in Science.
This is clearly not the only factor, given that about 90% of adults have antibodies indicating they have had Epstein-Barr, while nearly 1 million people in the US are living with multiple sclerosis, according to the National Multiple Sclerosis Society.
The virus appears to be the “initial trigger”. William H. Robinson and Lawrence Steinman of Stanford University wrote in an editorial accompanying the study on Thursday. But they warned that “additional fuses need to be fired” such as genes that can make people more vulnerable.
Epstein-Barr is best known for causing “mono”, or infectious mononucleosis, in teenagers and young adults, but is often asymptomatic. A virus that remains dormant in the body after initial infection has also been linked to the subsequent development of certain autoimmune diseases and rare cancers.
Inexplicably. Among the options is so-called “molecular mimicry,” meaning that viral proteins can look so similar to certain proteins in the nervous system that they trigger a mistaken immune attack.
However, the new study is “to date the most compelling evidence that Epstein-Barr contributes to multiple sclerosis,” said Mark Allegretta, vice president of research for the National Multiple Sclerosis Society.
And that, he added, “opens the door to potential prevention of multiple sclerosis by preventing Epstein-Barr infection.”
Efforts are being made to develop Epstein-Barr vaccines, including a small study just started by Moderna Inc., best known for its COVID-19 vaccine.