EBV can trick the immune system to attack myelin in at-risk individuals

Study shows how a common virus and genetic risk factors interact to trigger MS

Written by Marisa Wexler, MS | January 15, 2026

• Multiple sclerosis risk increases with Epstein-Barr virus infection and HLA-DR15 genetic variant.
• EBV infection causes B-cells with HLA-DR15 to “display” myelin proteins, triggering immune attacks.
• Understanding this mechanism may lead to new treatment strategies for multiple sclerosis.

A history of the Epstein-Barr virus (EBV) appears to alter the immune systems of people with specific genetic traits, causing their own cells to mistakenly flag brain proteins as dangerous threats, according to a new study.

This discovery offers insight into how these risk factors — viral infection and genetics — interact to contribute to the development of multiple sclerosis (MS), and could pave the way for new treatment strategies, researchers said.

“Our study shows how the most important environmental and genetic risk factors can contribute to MS and trigger an autoimmune response that targets myelin components in the brain,” Roland Martin, MD, who led the study at the University of Zurich, said in a university news story. “Our findings reveal mechanisms that could be targeted by new therapies.”

The study, “EBV infection and HLA-DR15 jointly drive multiple sclerosis by myelin peptide presentation,” was published in Cell.

The role of myelin in autoimmune attacks

In MS, the immune system launches an inflammatory attack in the brain and spinal cord that damages healthy myelin, a fatty substance essential for proper nerve functioning.

The causes of this self-targeting immune attack aren’t fully understood, but several risk factors have been identified. One of the strongest risk factors for MS is a history of EBV infection. Genetics is also thought to play a role.

EBV is best known as the cause of infectious mononucleosis, but it also causes a lot of non-specific childhood illnesses. Almost every adult has been infected with EBV at some point.

A large body of data has shown that EBV infection is a key risk factor for MS. In fact, many scientists think MS can develop only in people who have been infected with EBV. However, exactly how the infection leads to MS is poorly understood, and it’s not clear why only a small fraction of EBV-infected people develop the condition.

EBV primarily infects immune cells known as B-cells. One theory suggests that EBV infection may alter B-cell activity, predisposing an individual to MS. In this study, scientists found that EBV infection can alter the activity of a B-cell protein called the human leukocyte antigen (HLA).

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