ERVW-1 and myeloid sarcoma: The HERV-H envelope and gag proteins have been reported to be present in the serum of MS patients [55] and when patients with active disease were compared to those with inactive MS and with healthy controls, both the HERV-H envelope protein and an HERV-H single nucleotide polymorphisms were found only in immune blood cells derived from the first group [51,52].