Age at Epstein-Barr virus infection and Epstein-Barr virus nuclear antigen-1 antibodies in Swedish children.

There is strong evidence supporting a role for Epstein-Barr virus (EBV) in the etiopathogenesis of multiple sclerosis (MS). Because of the strong association between antibody (Ab) titer against EBV nuclear antigen 1 (EBNA1) and late age at EBV infection, manifested as infectious mononucleosis (IM), and MS risk, we sought to determine whether age at primary EBV infection was associated with subsequent anti-EBNA1 Ab titer in a longitudinal study of Swedish children with EBV seropositivity and anti-EBNA1 Ab titers measured at ages 2, 5, and 10.