IFNB1 and myeloid sarcoma: Based on the above described autoimmune nature of MS, these immunomodulatory drugs either target T cell proliferation (interferon-beta) [9], immune cell activation and inflammatory response (interferon beta, glatiramer acetate) [10,11], or the peripheric invasion of autoreactive T and B cells: Preventing the ability of these cells to egress from the lymph nodes (fingolimod) [12]; or inhibiting their crossing over the BBB (natalizumab) [13,14].