-A Monoclonal antibody that binds to the EBNA1 AA386–405 epitope and exhibits cross-reactivity with GlialCAM was found in the cerebrospinal fluid of an MS patient.-Immunization of mice with the EBNA1 epitope resulted in increased demyelination.-20% to 25% of MS patients have antibodies against GlialCAM and EBV EBNA1. Here, HEPACAM is linked to myeloid sarcoma.