Researchers at Karolinska Institutet have found further links between Epstein–Barr virus and multiple sclerosis. A study published in Science Advances shows that some individuals have antibodies against the virus that mistakenly attack a protein in the brain and spinal cord.
Many years ago, the Epstein–Barr virus (EBV), which infects most people early in life and then usually lies dormant was linked to multiple sclerosis (MS) but the reason remained a mystery. Increasing evidence, including two papers published in Science and Nature last year, suggests that EBV infection precedes MS and that antibodies against the virus may be involved. However, the molecular mechanisms seem to vary between patients and remain largely unknown.
“MS is an incredibly complex disease, but our study provides an important piece in the puzzle and could explain why some people develop the disease,” says Olivia Thomas, postdoctoral researcher at the Department of Clinical Neuroscience, Karolinska Institutet and shared first author of the paper. “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.”
The researchers analysed blood samples from more than 700 patients with MS and 700 healthy controls. They found that antibodies that bind to a certain protein in the Epstein-Barr virus, EBNA1, can also bind to a similar protein in the brain and spinal cord called CRYAB, whose role is to prevent protein aggregation during conditions of cellular stress such as inflammation. These misdirected, cross-reactive antibodies may damage the nervous system and cause severe symptoms in MS patients, including problems with balance, mobility and fatigue. The antibodies were present in about 23 percent of MS patients and 7% of control individuals.
“This shows that, whilst these antibody responses are not required for disease development, they may be involved in disease in up to a quarter of MS patients,” says Olivia Thomas. “This also demonstrates the high variation between patients, highlighting the need for personalised therapies. Current therapies are effective at reducing relapses in MS but unfortunately, none can prevent disease progression.”
“We are now expanding our research to investigate how T cells fight EBV infection and how these immune cells may damage the nervous system in multiple sclerosis and contribute to disease progression,” says joint first author of the paper Mattias Bronge, affiliated researcher at the Department of Clinical Neuroscience, Karolinska Institutet.
Source: Karolinska Institutet
