MOG and myeloid sarcoma: When excluding participants who met diagnostic criteria for MS, the occurrence of clinical relapses was more common among anti-MOG antibody–positive participants (9 of 71 [13%] vs 2 of 121 [2%]; P = .002), ie, 10 of 11 participants with relapsing non-MS disease (91%) were positive for anti-MOG antibody at presentation.