Epstein-Barr virus: how does a common infection trick the immune system into attacking the brain in people with MS?

Almost 3 million people worldwide have multiple sclerosis (MS) – an autoimmune disease caused by the immune system mistakenly attacking the brain and central nervous system. While treatments for MS have improved over the years, there’s still no cure. This is largely because researchers still don’t fully understand what goes wrong in the immune system to cause MS.

But our latest research has revealed new insights into the way certain immune cells behave in people with MS. This discovery brings us closer to understanding why some people get MS – and may also be a crucial step in developing better treatments and even cures. Although the causes of MS aren’t fully understood, we know that genetics, lifestyle and environment factors can all influence MS risk.

But the biggest risk factor for developing MS appears to be a common virus called Epstein-Barr virus (EBV) . EBV typically infects people during childhood without causing any symptoms – so most early infections go unnoticed. But if the infection occurs during adolescence, it may cause glandular fever (infectious mononucleosis) which, although debilitating in the short-term, usually has no long-term effects .

Most viral infections are rapidly cleared by the body’s immune system, but EBV is cleverer than most viruses. Although the immune system controls the infection, it is unable to completely eradicate the virus as it hides inside a type of immune cell called a B cell (which normally produce antibodies that bind .