It's thought that about 90 percent of the world's population has been infected at some point in their early lives with Epstein-Barr virus (EBV), a herpesvirus that is often asymptomatic. It can lead to mononucleosis in some people, and it can remain dormant in the body over a lifetime. Recent work has also indicated that EBV triggers the development of multiple sclerosis (MS), or promote the progression of the disease, which often affects the nervous system and causes mobility problems. Now scientists are learning more about how the virus is related to MS. Reporting in Science Advances, researchers determined that some people with multiple sclerosis carry antibodies against Epstein-Barr virus that erroneously attack a protein found in the central nervous system.
"We have discovered that certain antibodies against the Epstein-Barr virus, which would normally fight the infection, can mistakenly target the brain and spinal cord and cause damage," said co-first study author Olivia Thomas, a postdoctoral researcher at the Karolinska Institutet.
In this work, blood samples from over 700 MS patients were compared to an equal number of samples from unaffected people. The researchers identified antibodies in some of the MS patient blood that can bind to a protein generated by Epstein-Barr virus, EBNA1 as well as a protein in the brain and spinal cord known as CRYAB. These cross-reactive antibodies could be responsible for the damage in the nervous system that causes MS symptoms.
These antibodies were only found in 23 percent of MS patients, however, as well as seven percent of unaffected individuals. The antibodies may still be responsible for MS in about a quarter of patients, suggested Thomas.
"This also demonstrates the high variation between patients, highlighting the need for personalized therapies. Current therapies are effective at reducing relapses in MS but unfortunately, none can prevent disease progression," Thomas added.
Data from this study also indicated that these antibodies could be affecting T cells, and the researchers are following up on that information to learn more. These immune cells may also be having a negative impact on the nervous system and could be involved in the disorder, added co-first study author Mattias Bronge, a researcher with the Karolinska Institutet.
Sources: Karolinska Institutet, Science Advances