A role of late Epstein-Barr virus infection in multiple sclerosis

Objective - To assess Epstein-Barr virus (EBV) seroconversion in a high multiple sclerosis (MS) prevalence area and to evaluate the recall of diagnosed infectious mononucleosis in MS patients. Methods - The study was based on information or blood samples, or both, from schoolchildren, young MS patients and matched controls. EBV serology was performed on 1154 blood samples. Results - We demonstrate that more than one third of the population in a high MS prevalence area is seronegative to EBV at puberty. This is in contrast to the virtually complete seroconversion to EBV early in life in individuals from areas with a low prevalence of MS. Furthermore, we demonstrate that recall of diagnosed infectious mononucleosis (IM), but not recall of common childhood diseases, is significantly more frequent among MS patients than healthy controls. All MS patients, including patients without prior immunosuppressive treatment, were EBV seropositive. Conclusion - During or after puberty, EBV is transmitted to a major proportion of the population in an MS high-prevalence area. Together with our previous documentation of an association between late infection with EBV and an increased risk of developing MS, these data support a role of EBV infection in MS.