Despite the conclusive autoimmune trait of MS, the precise trigger for the CNS-directed autoimmune response is still unknown.Autoreactive T cells in the blood of MS patients display specificity for multiple myelin protein-derived antigens such as myelin basic protein (MBP), proteolipid protein, and myelin oligodendrocyte glycoprotein (MOG). Here, MOG is linked to myeloid sarcoma.