Recently, we showed that the binding to the plasmamembrane of EBVgp350, the major envelope protein of EBV, is sufficient to activate the potentially immunopathogenic and neuropathogenic HERV-W/MSRV/syncytin-1, in cells that may be involved in MS pathogenesis, deriving from blood and brain [13]. Here, ERVW-1 is linked to myeloid sarcoma.