ERVW-1 and myeloid sarcoma: The findings that have associated HERV‐W with the pathogenesis of MS include higher levels of HERV‐W expression and proviral load among MS patients [4, 5, 6], detection of HERV‐W env protein in active MS brain lesions [7, 8, 9], and induction of MS in animal model after exposition to HERV‐W‐env protein in mice [10].