The body’s immune response to Epstein-Barr virus may play a role in causing damage in people with multiple sclerosis, according to a new study.

EBV is a member of the herpes virus family that spreads most commonly through bodily fluids, especially saliva, and can cause infectious mononucleosis, among other illnesses. The EBV infection has long been linked to MS, but how the infection might contribute to MS has not been clear. More than 95 percent of people have been infected with the virus; however, it typically remains in its latent stage and doesn’t cause any issues. In some cases, though, the T-cells specific for the EBV infection may cause problems. 

New research, led by researchers at the University of Texas Health Science Center at Houston, demonstrates that T-cells specific for EBV-infected cells are present in high numbers in the cerebrospinal fluid of people with MS at its earliest stages. 

The researchers obtained blood and cerebrospinal fluid samples from eight patients in the process of MS diagnosis. They stimulated cells from the patients’ own blood with multiple different stimuli, including EBV-infected lymphoblastoid cell lines from the same person, cell-free EBV, varicella zoster virus (chicken pox); influenza virus, and candida; they then used RNA sequencing for T-cell receptors to determine which of the stimuli the cerebrospinal fluid T-cells were responding to. 

On average, 13 percent of the T-cells in the cerebrospinal fluid of people with the first symptoms of MS are specific for autologous B lymphocytes infected with EBV, demonstrating a clear link between EBV and MS. In the most expanded cerebrospinal fluid clones, which are highly likely to play a role in MS pathogenesis, the abundance of LCL-specific T-lymphocytes is even higher, at 47 percent. T-cells for the three other common infections did not show a similar abundance in the cerebrospinal fluid.

The study was published in the Proceedings of the National Academy of Sciences.