Antibodies to specific EBNA-1 domains and HLA DRB1*1501 interact as risk factors for multiple sclerosis.

Epitope reactivity of multiple sclerosis (MS) plasma antibodies against the Epstein-Barr virus protein EBNA-1 and its association with HLA DRB1*1501 status was investigated in a case-referent study. Based on EBNA-1 fragment reactivity and the effect of peptide blocking, four 29-36 amino acid long EBNA-1 fragments were selected for detailed studies. MS cases had increased antibody reactivity against several EBNA-1 domains, of which antibodies against EBNA-1 (amino acid 385-420) in HLA DRB1*1501 positive individuals were associated with a 24-fold risk increase for MS. The data need confirmation in a larger sample but suggest a role for this epitope in the autoimmune pathogenesis of MS.