Epstein-Barr virus may be leading cause of multiple sclerosis

Multiple sclerosis, a progressive disease that affects 2.8 million people worldwide and for which there is no definitive cure, is likely caused by infection with the Epstein-Barr virus, according to a study led by Harvard T.H. Chan School of Public Health researchers. Their findings will be published online in Science on January 13, 2022.

“The hypothesis that Epstein-Barr virus causes multiple sclerosis has been investigated by our group and others for several years, but this is the first study providing compelling evidence of causality,” said Alberto Ascherio, professor of epidemiology and nutrition at Harvard Chan School and senior author of the study. “This is a big step because it suggests that most multiple sclerosis cases could be prevented by stopping Epstein-Barr virus infection, and that targeting Epstein-Barr virus could lead to the discovery of a cure for multiple sclerosis.”

Multiple sclerosis is a chronic inflammatory disease of the central nervous system that attacks the myelin sheaths protecting neurons in the brain and spinal cord. Its cause is not known, yet one of the top suspects is Epstein-Barr virus, a herpes virus that can cause infectious mononucleosis and establishes a latent, lifelong infection of the host. Establishing a causal relationship between the virus and the disease has been difficult because Epstein-Barr virus infects approximately 95% of adults, multiple sclerosis is a relatively rare disease, and the onset of multiple sclerosis symptoms begins about ten years after Epstein-Barr virus infection. To determine the connection between Epstein-Barr virus and multiple sclerosis, the researchers conducted a study among more than 10 million young adults on active duty in the U.S. military and identified 955 who were diagnosed with multiple sclerosis during their period of service.

The team analyzed serum samples taken biennially by the military and determined the soldiers’ Epstein-Barr virus status at time of first sample and the relationship between Epstein-Barr virus infection and multiple sclerosis onset during the period of active duty. In this cohort, the risk of multiple sclerosis increased 32-fold after infection with Epstein-Barr virus but was unchanged after infection with other viruses. Serum levels of neurofilament light chain, a biomarker of the nerve degeneration typical in multiple sclerosis, increased only after Epstein-Barr virus infection. The findings cannot be explained by any known risk factor for multiple sclerosis and suggest Epstein-Barr virus as the leading cause of multiple sclerosis.

Ascherio says that the delay between Epstein-Barr virus infection and the onset of multiple sclerosis may be partially due the disease’s symptoms being undetected during the earliest stages and partially due to the evolving relationship between Epstein-Barr virus and the host’s immune system, which is repeatedly stimulated whenever latent virus reactivates.

“Currently there is no way to effectively prevent or treat Epstein-Barr virus infection, but an Epstein-Barr virus vaccine or targeting the virus with Epstein-Barr virus-specific antiviral drugs could ultimately prevent or cure multiple sclerosis,” said Ascherio.

Source: News Release
University of Virginia Health System
January 13, 2022