Genetic trait clue in EBV and MS link puzzle

A new study suggests that a past infection with the Epstein Barr virus may change how the immune system behaves in people with certain genetic traits, increasing the likelihood of the body mistakenly attacking its own brain tissue. Researchers say this could help explain how viral infection and genetics come together to influence the risk of developing multiple sclerosis (MS).

While the exact causes of MS remain unclear, scientists know that both environmental and genetic factors play a role.

One of the strongest known risk factors for MS is infection with the Epstein-Barr virus. This virus is extremely common and most adults will have been infected at some point in their lives, often during childhood. Despite this, only a small number of people go on to develop MS, which has left researchers searching for answers as to why.

In this study, scientists focused on how EBV affects immune cells known as B cells. These cells help the immune system identify potential threats. The researchers found that EBV infection can change how B cells behave in people who carry a specific genetic variation known to increase MS risk.

This genetic variation affects a protein that helps immune cells present fragments of material to the rest of the immune system. In people with this genetic trait, EBV infected B cells were found to display fragments of myelin, even though myelin is part of the body’s own healthy tissue. This does not happen in uninfected B cells.

To support their findings, the researchers also examined brain tissue from people with MS who had this genetic profile. They found EBV infected B cells displaying myelin fragments in the brain. Further laboratory work showed that other immune cells could react to these signals, potentially triggering an immune response against myelin.

Together, these findings suggest that in some people, EBV infection may prompt the immune system to mistake myelin for a threat, leading to inflammation and damage over time. This could help explain why MS develops only in certain people, even though EBV infection is widespread.

The researchers say this discovery improves understanding of how MS may develop and could open the door to future treatments that target these immune interactions. However, this research does not mean that EBV alone causes MS, nor does it change current advice for people living with or affected by MS.