This antibody was often found in patients with NMO, but very rarely in patients with other conditions (e.g. MS) and it was concluded that NMO-IgG is a specific and diagnostic marker autoantibody of NMO.9–11 Furthermore, myelin oligodendrocyte glycoprotein (MOG) autoantibodies have been extensively studied in experimental models of MS. Here, OMG is linked to myeloid sarcoma.