Viral exposures and MS outcome in a prospective cohort of children with acquired demyelination.

Epstein-Barr virus (EBV) infection is associated with increased multiple sclerosis (MS) risk. Recently, cytomegalovirus (CMV) infection has been proposed as a protective factor against MS development. We determined EBV, herpes simplex virus, varicella-zoster virus and CMV seroprevalence in 247 prospectively followed children with acquired demyelinating syndromes (ADS). Remote EBV infection was more common in children with MS than those with monophasic ADS while CMV infection was more common in children with monophasic ADS. Children displaying evidence of remote EBV without CMV infection were at highest risk of subsequent MS diagnosis. Viral infection repertoire detected at ADS provides important prognostic information.