Lopez-Chiriboga, A Sebastian

Background: Magnetic resonance imaging (MRI) T2-lesions resolve more often in myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) than aquaporin-4 IgG-positive neuromyelitis optica spectrum disorder (AQP4 + NMOSD) and multiple sclerosis (MS) in adults but few studies analyzed children. Objective: The main objective of this study is to investigate MRI T2-lesion evolution in pediatric MOGAD, AQP4 + NMOSD, and MS. Methods: Inclusion criteria were as follows: (1) first clinical attack; (2) abnormal MRI (⩽6 weeks); (3) follow-up MRI beyond 6 months without relapses in that region; and (4) age < 18 years. An index T2-lesion (symptomatic/largest) was identified, and T2-lesion resolution or persistence on follow-up MRI was determined. Results: We included 56 patients (MOGAD, 21; AQP4 + NMOSD, 8; MS, 27) with 69 attacks. Index T2-lesion resolution was more frequent in MOGAD (brain 9 of 15 [60%]; spine 8 of 12 [67%]) than AQP4 + NMOSD (brain 1 of 4 [25%]; spine 0 of 7 [0%]) and MS (brain 0 of 18 [0%]; spine 1 of 13 [8%]), p < 0.01. Resolution of all T2-lesions occurred more often in MOGAD (brain 6 of 15 [40%]; spine 7 of 12 [58%]) than AQP4 + NMOSD (brain 1 of 4 [25%]; spine 0 of 7 [0%]), and MS (brain 0 of 18 [0%]; spine 1 of 13 [8%]), p < 0.01. Reductions in median index T2-lesion area were greater in MOGAD (brain, 305 mm; spine, 23 mm) than MS (brain, 42 mm [ p<0.001]; spine, 10 mm [ p<0.001]) without differing from AQP4 + NMOSD (brain, 133 mm [ p=0.42]; spine, 19.5 mm [ p=0.69]). Conclusion: In children, MRI T2-lesions resolved more often in MOGAD than AQP4 + NMOSD and MS which is similar to adults suggesting these differences are related to pathogenesis rather than age.

Cerebral cortical encephalitis (CCE) is a recently described myelin oligodendrocyte glycoprotein antibody‐associated disease (MOGAD) phenotype. In this observational retrospective study, we characterized 19 CCE patients (6.7% of our MOGAD cohort). Headache (n = 15, 79%), seizures (n = 13, 68%), and encephalopathy (n = 12, 63%) were frequent. Magnetic resonance imaging revealed unilateral (n = 12, 63%) or bilateral (n = 7, 37%) cortical T2 hyperintensity and leptomeningeal enhancement (n = 17, 89%). N‐Methyl‐D‐aspartate receptor autoantibodies coexisted in 2 of 15 tested (13%). CCE pathology (n = 2) showed extensive subpial cortical demyelination (n = 2), microglial reactivity (n = 2), and inflammatory infiltrates (perivascular, n = 1; meningeal, n = 1). Most received high‐dose steroids (n = 17, 89%), and all improved, but 3 had CCE relapses. This study highlights the CCE spectrum and provides insight into its pathogenesis. ANN NEUROL 2023;93:297–302

Background and ObjectivesWe sought to determine clinical significance of neuronal septin autoimmunity and evaluate for potential IgG effects.MethodsSeptin‐IgGs were detected by indirect immunofluorescence assays (IFAs; mouse tissue and cell based) or Western blot. IgG binding to (and internalization of) extracellular septin epitopes were evaluated for by live rat hippocampal neuron assay. The impact of purified patient IgGs on murine cortical neuron function was determined by recording extracellular field potentials in a multielectrode array platform.ResultsSeptin‐IgGs were identified in 23 patients. All 8 patients with septin‐5‐IgG detected had cerebellar ataxia, and 7 had prominent eye movement disorders. One of 2 patients with co‐existing septin‐7‐IgG had additional psychiatric phenotype (apathy, emotional blunting, and poor insight). Fifteen patients had septin‐7 autoimmunity, without septin‐5‐IgG detected. Disorders included encephalopathy (11; 2 patients with accompanying myelopathy, and 2 were relapsing), myelopathy (3), and episodic ataxia (1). Psychiatric symptoms (≥1 of agitation, apathy, catatonia, disorganized thinking, and paranoia) were prominent in 6 of 11 patients with encephalopathic symptoms. Eight of 10 patients with data available (from 23 total) improved after immunotherapy, and a further 2 patients improved spontaneously. Staining of plasma membranes of live hippocampal neurons produced by patient IgGs (subclasses 1 and 2) colocalized with pre‐ and post‐synaptic markers. Decreased spiking and bursting behavior in mixed cultures of murine glutamatergic and GABAergic cortical neurons produced by patient IgGs were attributable to neither antigenic crosslinking and internalization nor complement activation.InterpretationSeptin‐IgGs are predictive of distinct treatment‐responsive autoimmune central nervous system (CNS) disorders. Live neuron binding and induced electrophysiologic effects by patient IgGs may support septin‐specific pathophysiology. ANN NEUROL 2022;92:1090–1101

Objective Determine the utility of aquaporin 4 IgG (AQP4-IgG) testing (live cell-based assay) for Neuromyelitis Optica Spectrum Disorders (NMOSD). Methods We included Mayo Clinic patients (1/1/2018-12/31/2019) tested for serum AQP4-IgG by live cell-based flow-cytometric assay. Medical records were reviewed to assess if patients fulfilled 2015 NMOSD criteria. Results Of 1371 patients tested, 41 were positive (3%) and all fulfilled NMOSD criteria with AQP4-IgG (specificity = 100%). Only 10/1330 testing negative met NMOSD criteria without AQP4-IgG (sensitivity = 80%) and seven of these 10 were MOG-IgG positive. Conclusions AQP4-IgG by live cell-based assay was highly specific and without false positives in a high throughput setting.

Background Myelin-oligodendrocyte-glycoprotein (MOG)-IgG-positivity in patients with typical MS lesions on MRI may lead to diagnostic/therapeutic uncertainty. Objective and Methods We reviewed reports of cases with MS phenotype on MRI and MOG-IgG-positivity published in Pubmed between 01/2012–06/2021. Results Sixteen patients were included (median age [range], 37,5 [25–66] years; 60% female). Three patients initially tested negative for MOG-IgG. Disease course was: relapsing-remitting, 10; or progressive, 6. Intrathecal IgG-synthesis was common (79%). Low and high-efficacy MS-targeted agents prevented relapses in 30% and 100%, respectively. None of the patients showed resolution of MRI T2-lesions over time. Conclusions MOG-IgG-positivity is unlikely to alter the expected treatment response and outcomes in patients with otherwise typical MS phenotype on MRI.