Printed Poster | Session 1

033 – Prospective characterization of children positive for anti-MOG antibodies meeting Multiple Sclerosis diagnostic criteria.

Giulia Fadda (1, 2*) – Patrick Waters (3*) – Mark Woodhall (3) – Sarosh Irani (3) – Robert A. Brown (1) – Julia O’Mahony (4) – Denise A. Castro (5) – Giulia Longoni (6) – E. Ann Yeh (6) – Ruth Ann Marrie (7) – Douglas L. Arnold (1) – Brenda Banwell (2, 8) – Amit Bar-Or (1, 2, 8) on behalf of the Canadian/CHOP Pediatric Demyelinating Disease Network
Montreal Neurological Institute, McGill University, Montreal, QC, Canada (1) – Center for Neuroinflammation and Neurotherapeutics, and Multiple Sclerosis Division, Department of Neurology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA (2) – Neuroimmunology Unit, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada (3) – Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, UK (3) – Institute of Health Policy, Management and Evaluation, the University of Toronto/The Hospital for Sick Children, Toronto, ON, Canada (4) – Department of Diagnostic Imaging, Neurosciences and Mental Health, SickKids Research Institute (5) – Department of Pediatrics, University of Toronto, Toronto, ON, Canada (6) – Departments of Internal Medicine and Community Health Sciences, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada (7) – Division of Child Neurology, Department of Neurology, The Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA (8)

A minority of subjects meeting the multiple sclerosis (MS) diagnostic criteria are seropositive for antibodies against myelin oligodendrocyte glycoprotein (MOGabs). Whether these patients exhibit clinical features distinct from typical MS is unclear. We characterized the clinical features and outcome of 66 children (median [IQR] age at onset 13.97 [IQR 10.88-15.06] years) with a diagnosis of MS according to 2017 international diagnostic criteria, who were assessed for the presence of MOGabs. Clinical, serological and imaging features were prospectively assessed for a median of 7 years from presentation, and compared between MOG+ and MOG- children using descriptive statistics. At clinical onset, 11/66 (17%) children were MOG+. Seropositive patients were younger (p<0.0001) than seronegative patients, and all presented at age <11 years. The presenting phenotype was optic neuritis (ON) and/or transverse myelitis (TM) for 80% of seropositive versus 41% of the seronegative patients (p =0.019). Brain MRIs at onset were atypical for MS in 9 MOG+ (3 without brain lesions, 3 with diffuse bilateral pattern and 3 with minimal lesions) and 4 MOG- patients (p<0.0001). Oligoclonal bands (OCBs) were detected in 2/8 (25%) MOG+ and 20/36 (83%) MOG- patients evaluated (p =0.0027). None of the MOG+ patients showed contrast enhancement on baseline MRI, thus none met 2010 McDonald criteria at onset; 2 MOG+ patients met the 2017 criteria due to the presence of OCBs. Of 11 MOG+ patients, 10 developed new brain lesions, 1 developed new spinal cord lesions, and 7 experienced clinical relapses (in almost all cases ON or TM). At last follow-up, total T2 lesion volume was smaller in MOG+ than MOG- patients (p<0.0001). Our findings suggest that, while meeting MS diagnostic criteria, children seropositive for MOGabs exhibit clinical and MRI features distinguishing them from MOG-negative typical relapsing MS patients.