Intrathecal synthesis of Epstein-Barr virus antibodies 15 years before onset of multiple sclerosis.

A 48-year-old woman was diagnosed with multiple sclerosis (MS) in 2019. She participated with blood and cerebrospinal fluid samples as a spinal anaesthesia surgery patient for a case-control study on viruses and MS in 2003. The study had already demonstrated intrathecal antibody synthesis (ITS) to Epstein-Barr virus (EBV) but not against measles, rubella and varicella-zoster (MRZ) reaction viruses in this individual at the time of recruitment. A 2025 study review established that she was the only patient in her control subgroup who also developed MS. This case shows that a specific EBV-ITS may be an early indicator of a 'biologically isolated syndrome' in MS.