Clinical, Radiologic, and Prognostic Features of Myelitis Associated With Myelin Oligodendrocyte Glycoprotein Autoantibody

Abstract

Importance: Recognizing the characteristics of myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) myelitis is essential for early accurate diagnosis and treatment.

Objective: To evaluate the clinical, radiologic, and prognostic features of MOG-IgG myelitis and compare with myelitis with aquaporin-4-IgG (AQP4-IgG) and multiple sclerosis (MS).

Design, setting, and participants: We retrospectively identified 199 MOG-IgG-positive Mayo Clinic patients from January 1, 2000, through December 31, 2017, through our neuroimmunology laboratory. Fifty-four patients met inclusion criteria of (1) clinical myelitis; (2) MOG-IgG positivity; and (3) medical records available. We excluded 145 patients without documented myelitis. Myelitis of AQP4-IgG (n = 46) and MS (n = 26) were used for comparison.

Main outcomes and measures: Outcome variables included modified Rankin score and need for gait aid. A neuroradiologist analyzed spine magnetic resonance imaging of patients with MOG-IgG and control patients blinded to diagnosis.

Results: Of 54 included patients with MOG-IgG myelitis, the median age was 25 years (range, 3-73 years) and 24 were women (44%). Isolated transverse myelitis was the initial manifestation in 29 patients (54%), and 10 (19%) were initially diagnosed as having viral/postviral acute flaccid myelitis. Cerebrospinal fluid-elevated oligoclonal bands occurred in 1 of 38 (3%). At final follow-up (median, 24 months; range, 2-120 months), 32 patients (59%) had developed 1 or more relapses of optic neuritis (n = 31); transverse myelitis (n = 7); or acute disseminated encephalomyelitis (n = 1). Clinical features favoring MOG-IgG myelitis vs AQP4-IgG or MS myelitis included prodromal symptoms and concurrent acute disseminated encephalomyelitis. Magnetic resonance imaging features favoring MOG-IgG over AQP4-IgG or MS myelitis were T2-signal abnormality confined to gray matter (sagittal line and axial H sign) and lack of enhancement. Longitudinally extensive T2 lesions were of similar frequency in MOG-IgG and AQP4-IgG myelitis (37 of 47 [79%] vs 28 of 34 [82%]; P = .52) but not found in MS. Multiple spinal cord lesions and conus involvement were more frequent with MOG-IgG than AQP4-IgG but not different from MS. Wheelchair dependence at myelitis nadir occurred in one-third of patients with MOG-IgG and AQP4-IgG but never with MS, although patients with MOG-IgG myelitis recovered better than those with AQP4-IgG.

Conclusions and relevance: Myelitis is an early manifestation of MOG-IgG-related disease and may have a clinical phenotype of acute flaccid myelitis. We identified a variety of clinical and magnetic resonance imaging features that may help clinicians identify those at risk in whom MOG-IgG should be tested.

Figure 1.. Examples of Magnetic Resonance Imaging (MRI) Findings in Myelin Oligodendrocyte Glycoprotein Autoantibody (MOG-IgG) Myelitis

A, An adult patient with a sagittal T2-hyperintense line (blue arrowhead) that is surrounded by fainter T2 hyperintensity (yellow arrowheads), with a corresponding T2 hyperintensity highly restricted to the gray matter on axial sequences forming an H sign (red arrowhead). B, A pediatric patient with a sagittal line of T2 hyperintensity (yellow arrowhead) confined to gray matter on axial images forming an H sign (red arrowhead). C, An adult patient with 2 noncontiguous T2-hyperintense lesions in the cervical cord extending 2.5 and 1 vertebral segments (yellow arrowhead); the upper lesion has a vague appearance of a central line. The axial sequences show central T2 hyperintensity most prominent at the central canal and fainter signal surrounding that is confined to gray matter vaguely resembling an H sign (red arrowhead). D, A pediatric patient is shown with 2 longitudinally extensive T2 hyperintense lesions on sagittal sequences, 1 in the cervical cord and 1 in the conus (yellow arrowheads). On axial sequences, this lesion shows central predominant signal abnormality that is more diffuse and not confined to gray matter (red arrowhead).

Figure 2.. Comparison of Myelitis With Myelin Oligodendrocyte Glycoprotein Autoantibody (MOG-IgG), Aquaporin-4–IgG (AQP4-IgG), and Multiple Sclerosis (MS) Myelitis

A, An adult patient with MOG-IgG myelitis is shown in which a sagittal T2-hyperintense line (white arrowhead) is present surrounded by hazier T2 hyperintensity (yellow arrowheads) forming a longitudinally extensive spinal cord lesion accompanied by mild spinal cord swelling. On axial sequences, the T2 hyperintensity is highly restricted to the gray matter forming an H sign (red arrowhead). Postgadolinium sagittal images demonstrate no gadolinium enhancement. B, In contrast, an adult patient with AQP4-IgG positive neuromyelitis optica spectrum disorder (NMOSD) and a longitudinally T2 hyperintense extensive lesion with prominent swelling (yellow arrowheads) and an axial T2 lesion shows diffuse central signal abnormality not confined to gray matter (red arrowhead). The lesion has accompanying gadolinium enhancement (blue arrowheads). C, An adult patient with MS has a short T2-hyperintense lesion at the C2 level extending one vertebral segment in length (yellow arrowhead) with accompanying faint ring enhancement (blue arrowhead). On axial sequences, the lesion is located in the periphery of the cord in the right dorsal column (red arrowhead).