ERVW-1 and myeloid sarcoma: Furthermore, the implication in the immune dysregulation locally in the central nervous system (CNS) in MS can be inferred by the increase in the HERV-H and HERV-W Env epitopes on the B-cells and peripheral mononuclear cells in patients with MS relapse compared to non-relapsing patients and controls, and also, in these patients, these epitopes demonstrated increased sero-reactivity [52].