The structure and function of myelin oligodendrocyte glycoprotein

MOG Antibody Disease: Nuances in Presentation, Diagnosis, and Management

PURPOSE OF REVIEW

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is a distinct neuroinflammatory condition characterized by attacks of optic neuritis, transverse myelitis, and other demyelinating events. Though it can mimic multiple sclerosis and neuromyelitis optica spectrum disorder, distinct clinical and radiologic features which can discriminate these conditions are now recognized. This review highlights recent advances in our understanding of clinical manifestations, diagnosis, and treatment of MOGAD.

RECENT FINDINGS

Studies have identified subtleties of common clinical attacks and identified more rare phenotypes, including cerebral cortical encephalitis, which have broadened our understanding of the clinicoradiologic spectrum of MOGAD and culminated in the recent publication of proposed diagnostic criteria with a familiar construction to those diagnosing other neuroinflammatory conditions. These criteria, in combination with advances in antibody testing, should simultaneously lead to wider recognition and reduced incidence of misdiagnosis. In addition, recent observational studies have raised new questions about when to treat MOGAD chronically, and with which agent. MOGAD pathophysiology informs some of the relatively unique clinical and radiologic features which have come to define this condition, and similarly has implications for diagnosis and management. Further prospective studies and the first clinical trials of therapeutic options will answer several remaining questions about the peculiarities of this condition.

The dynamics of oligodendrocyte populations following permanent ischemia promotes long-term spontaneous remyelination of damaged area

Stroke is a major public health concern, with limited clinically approved interventions available to enhance sensorimotor recovery beyond reperfusion. Remarkably, spontaneous recovery is observed in certain stroke patients, suggesting the existence of a brain self-repair mechanism not yet fully understood. In a rat model of permanent cerebral ischemia, we described an increase in oligodendrocytes expressing 3RTau in damaged area. Considering that restoration of myelin integrity ameliorates symptoms in many neurodegenerative diseases, here we hypothesize that this cellular response could trigger remyelination. Our results revealed after ischemia an early recruitment of OPCs to damaged area, followed by their differentiation into 3RTau+ pre-myelinating cells and subsequent into remyelinating oligodendrocytes. Using rat brain slices and mouse primary culture we confirmed the presence of 3RTau in pre-myelinating and a subset of mature oligodendrocytes. The myelin status analysis confirmed long-term remyelination in the damaged area. Postmortem samples from stroke subjects showed a reduction in oligodendrocytes, 3RTau+ cells, and myelin complexity in subcortical white matter. In conclusion, the dynamics of oligodendrocyte populations after ischemia reveals a spontaneous brain self-repair mechanism which restores the functionality of neuronal circuits long-term by remyelination of damaged area. This is evidenced by the improvement of sensorimotor functions in ischemic rats. A deep understanding of this mechanism could be valuable in the search for alternative oligodendrocyte-based, therapeutic interventions to reduce the effects of stroke.

Myelin Oligodendrocyte Glycoprotein-Antibody Associated Disease: An Updated Review of the Clinical Spectrum, Pathogenetic Mechanisms and Therapeutic Management

Clinical syndromes associated with antibodies against myelin oligodendrocyte glycoprotein (MOG) are now recognized as a distinct neurological disease entity, and are gaining increasing attention. The pathogenic mechanisms underlying MOG-antibody disease (MOGAD) remain incompletely understood. Case series, facilitated by registries, and observational studies over the past few years have shed increasing light on the clinical aspects and therapeutic approaches of MOGAD. MOGAD may manifest with a variety of clinical syndromes, including acute disseminated encephalomyelitis (ADEM), autoimmune encephalitis, optic neuritis (ON) and transverse myelitis (TM). MOGAD can be either monophasic or relapsing. This review aims to provide a comprehensive updated description of the clinical spectrum, paraclinical features, and prognosis of MOG-antibody disease, as well as summarize its therapeutic considerations. Randomized clinical trials, standardized diagnostic criteria and treatment guidelines are the steps forward.

Lactate Dehydrogenase-Elevating Virus Infection Inhibits MOG Peptide Presentation by CD11b+CD11c+ Dendritic Cells in a Mouse Model of Multiple Sclerosis

Infections may affect the course of autoimmune inflammatory diseases of the central nervous system (CNS), such as multiple sclerosis (MS). Infections with lactate dehydrogenase-elevating virus (LDV) protected mice from developing experimental autoimmune encephalomyelitis (EAE), a mouse counterpart of MS. Uninfected C57BL/6 mice immunized with the myelin oligodendrocyte glycoprotein peptide (MOG35-55) experienced paralysis and lost weight at a greater rate than mice who had previously been infected with LDV. LDV infection decreased the presentation of the MOG peptide by CD11b+CD11c+ dendritic cells (DC) to pathogenic T lymphocytes. When comparing non-infected mice to infected mice, the histopathological examination of the CNS showed more areas of demyelination and CD45+ and CD3+, but not Iba1+ cell infiltration. These results suggest that the protective effect of LDV infection against EAE development is mediated by a suppression of myelin antigen presentation by a specific DC subset to autoreactive T lymphocytes. Such a mechanism might contribute to the general suppressive effect of infections on autoimmune diseases known as the hygiene hypothesis.

Neuromyelitis Optica Spectrum Disorders and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

For over two centuries, clinicians have been aware of various conditions affecting white matter which had come to be grouped under the umbrella term multiple sclerosis. Within the last 20 years, specific scientific advances have occurred leading to more accurate diagnosis and differentiation of several of these conditions including, neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody disease. This new understanding has been coupled with advances in disease-modifying therapies which must be accurately applied for maximum safety and efficacy.

The crucial role of gadolinium-enhanced MRI in a case of amaurosis fugax - a case report and literature review

Optic perineuritis is the inflammation of the optic nerve sheath. This affliction can lead to visual field impairment and other signs and symptoms related to the orbital space, such as pain, disc edema, ophthalmoplegia, proptosis. However, not all patients present with such suggestive symptoms, requiring a thorough assessment. We report the case of a young male admitted to our hospital for recurrent episodes of monocular blindness. Amaurosis fugax is a well-known presentation of transient ischemic attacks (TIA) and it was ruled out. Gadolinium-enhanced MRI revealed a typical aspect of optic perineuritis. It was mandatory to consider all possible causes of secondary optic perineuritis as they all represent serious clinical conditions, even if the idiopathic form is more frequent. The clinical and paraclinical evaluation of the patient excluded an underlying disease and primary optic perineuritis was diagnosed. Corticosteroid therapy is usually curative and a course of methylprednisolone was initiated for our patient with good outcome. However, response to treatment is not diagnostic as both primary and secondary optic perineuritis are normally responsive, hence thorough differential diagnosis is necessary.

Proteomic profiling of cerebrospinal fluid in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder of the central nervous system.

METHODS

Extracted proteins from 34 cerebrospinal fluid (CSF) samples [patients with MOGAD (MOG group, n = 12); healthy controls (HC group, n = 12); patients with MOG seronegative and metagenomics next-generation sequencing-negative inflammatory neurological diseases (IND group, n = 10)] were processed and subjected to label-free quantitative proteomics. Supervised partial least squares-discriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) models were also performed based on proteomics data. Functional analysis of differentially expressed proteins (DEPs) was performed using Gene Ontology, InterPro, and Kyoto Encyclopedia Genes and Genomes. An enzyme-linked immunosorbent assay was used to determine the complement levels in serum from patients with MOGAD.

RESULTS

Four hundred and twenty-nine DEPs (149 upregulated and 280 downregulated proteins) were identified in the MOG group compared to the HC group according to the P value and fold change (FC). Using the O-PLS-DA model, 872 differentially abundant proteins were identified with variable importance projection (VIP) scores > 1. Five proteins (gamma-glutamyl hydrolase, cathepsin F, interalpha-trypsin inhibitor heavy chain 5, latent transforming growth factor beta-binding protein 4 and leukocyte-associated immunoglobulin-like receptor 1) overlapping between the top 30 DEPs with top-ranked P value and FC and top 30 proteins in PLS-DA VIP lists were acquired. Functional analysis revealed that the dysregulated proteins in the MOG group were primarily involved in complement and coagulation cascades, cell adhesion, axon guidance, and glycosphingolipid biosynthesis compared to the HC group.

CONCLUSION

The proteomic alterations in CSF samples from children with MOGAD identified in the current study might provide opportunities for developing novel biomarker candidates.

Milk and multiple sclerosis: A possible link?

Despite having been formally defined over 150 years ago, the etiology of multiple sclerosis (MS) is still relatively unknown. However, it is now recognized as a multifactorial disease in which genetics, infection, immune function, and environment play a role. We propose an additional piece to the puzzle: milk. In this review, milk is highlighted as a potential risk factor for MS. We examine the overall correlation between bovine milk consumption and the incidence of MS. We then discuss possible mechanisms that may explain the positive association between milk consumption and the development of MS. For instance, butyrophilin (BTN), a milk glycoprotein, can provide molecular mimicry of myelin oligodendrocyte glycoprotein and induce an autoinflammatory response against myelin. Other milk components such as casein, gangliosides, xanthine oxidase, and saturated fats are also analyzed for their potential involvement in the pathophysiology of MS. Finally, we fit milk alongside other well known risk factors of MS: vitamin D levels, Epstein Barr virus infection, and gut dysbiosis. In conclusion, this review summarizes potential mechanisms linking milk as an underappreciated potential risk factor for the development of MS.

Thyroid hormone dysfunction in MOGAD and other demyelinating diseases

BACKGROUND

Thyroid hormones play a critical role in both neuronal and glial cell functions. Multiple sclerosis (MS) has increased co-occurrence with autoimmune thyroid diseases, and recent studies have suggested a potential link between neuromyelitis optica spectrum disorder (NMOSD) and thyroid hormones. However, no previous studies have examined the relationship between thyroid hormones and myelin oligodendrocyte glycoprotein-associated demyelination (MOGAD).

METHODS

We investigated the role of thyroid hormones in central nervous system (CNS) autoimmune demyelinating diseases in 26 MOGAD patients, 52 NMOSD patients, 167 patients with MS, and 16 patients with other noninflammatory neurological disorders. Thyroid hormone levels and clinical data (Expanded Disability Status Scale [EDSS]) were analyzed. Volumetric brain information was determined in brain magnetic resonance imaging (MRI) using the MDbrain platform.

RESULTS

MOGAD patients had significantly higher levels of free triiodothyronine (FT3) compared to NMOSD patients. No correlation was found between FT3 levels and disease severity or brain volume. Thyroid-stimulating hormone (TSH) levels did not differ significantly between the groups, but in NMOSD patients, higher TSH levels were associated with lower disability scores and increased brain volume. No significant differences in free thyroxine (FT4) levels were observed between the different groups, however, FT4 levels were significantly higher in relapsing versus monophasic MOGAD patients and increased FT4 levels were associated with a higher EDSS and lower brain volume in NMOSD patients.

CONCLUSION

Our findings highlight the potential involvement of thyroid hormones specifically in MOGAD patients and other demyelinating CNS disorders. Understanding the role of thyroid hormones in relapsing vs monophasic MOGAD patients and in comparison to other demyelinating disorder could lead to the development of therapeutic interventions. Further studies are needed to explore the precise mechanisms and potential interventions targeting the thyroid axis as a treatment strategy.

Global trends in research on MOG antibody-associated disease: bibliometrics and visualization analysis

Objective

The purpose of this study was to investigate the current research status, focus areas, and developmental trends in the field of Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) through an analysis of scientific literature.

Methods

The relevant research articles on MOGAD published from 1947 to 2022 were retrieved from the Web of Science database. The quantitative output of MOGAD related research articles, their distribution by country/region, data on collaborative publishing, influential authors, high-yield institutions, keywords, hotspots, and development trends were analyzed. Additionally, visual knowledge maps were generated using VOSviewer and Citespace.

Results

There has been a steady increase in the number of MOGAD related publications indicating that the subject has garnered increasing interest among researchers globally. The United States has been the leading contributor with 496 papers (19.25%), followed by China (244, 9.63%), Japan (183, 7.10%), the United Kingdom (154, 5.98%), and Germany (149, 5.78%). Among these countries, the United Kingdom boasts the highest citation frequency at the rate of 46.49 times per paper. Furthermore, active collaboration in MOGAD related research is observed primarily between the United States and countries such as Canada, Germany, Australia, Italy, the United Kingdom and Japan. Mayo Clinic ranks first in total articles published (109) and frequency of citations per article (77.79). Takahashi Toshiyuki from Tohoku University is the most prolific author, while Multiple Sclerosis and Related Disorders is the most widely read journal in this field. "Disease Phenotype", "Treatment", "Novel Coronavirus Infection and Vaccination", "Immunopathological Mechanisms", "Clinical characteristics of children" and "Prognosis" are the primary keywords clusters in this field. "Novel Coronavirus Infection and Vaccination" and "Immunopathological Mechanisms" are research hotspots and have great development potential.

Conclusion

The past three decades have witnessed a significant expansion of research on MOGAD. The pathogenetic mechanism of MOGAD is poised to be the prominent research focus in this field in the foreseeable future.

Clinical Features of Patients with Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease and Isolated Seizure Symptoms

Background

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated encephalitis is a new clinical phenotype of inflammatory demyelinating diseases. Some MOG antibody-positive patients with central nervous system demyelinating events present with isolated seizures. However, there are gaps in the epidemiological knowledge regarding seizures with MOG antibody-associated encephalitis in adults. This study characterized the clinical features and treatment of MOG antibody-positive patients with isolated seizures.

Methods

We reviewed all the patients admitted to Tianjin Huanhu Hospital between Jan. 1st 2017 and Jan. 1st 2022, to screen the MOG antibody-positive patients with isolated seizures, and collected the concerned patients' information regarding epidemiology, clinical presentations, laboratory and radiological characteristics, electroencephalogram (EEG), treatments, and prognoses.

Results

We collected six MOG antibody-positive adult patients who had isolated symptomatic seizures. The mean age of the patients was 33 years (range, 29-40 years), and five (83.3%) were men. All patients presented with motor seizures, five (83.3%) had cognitive dysfunction, and only one (16.7%) had status epilepticus. Five (83.3%) patients had a good response to immunotherapy and antiseizure medications; only one had a sequela. The cerebrospinal fluid or serum anti-MOG antibody test turned negative over time.

Discussion

The most common seizure type in patients with MOG antibody-associated encephalitis with isolated seizures was focal to bilateral tonic-clonic seizures, and most patients had a good prognosis. Adding antiseizure medications were beneficial for MOG antibody-positive patients with seizures. Relapses and sequelae were associated with low-dose, short-time, or delayed therapy, and wide-range demyelinating brain damage.

Monoclonal antibodies in neuro-ophthalmology

Neuro-ophthalmologic diseases include a broad range of disorders affecting the afferent and efferent visual pathways. Recently, monoclonal antibody (mAb) therapies have emerged as a promising targeted approach in the management of several of these complex conditions. Here, we describe the mechanism-specific applications and advancements in neuro-ophthalmologic mAb therapies. The application of mAbs in neuro-ophthalmologic diseases highlights our increasing understanding of disease-specific mechanisms in autoimmune conditions such as neuromyelitis optica, thyroid eye disease, and myasthenia gravis. Due to the specificity of mAb therapies, applications in neuro-ophthalmologic diseases have yielded exceptional clinical outcomes, including both reduced rate of relapse and progression to disability, visual function preservation, and quality of life improvement. These advancements have not only expanded the range of treatable neuro-ophthalmologic diseases but also reduced adverse events and increased the response rate to treatment. Further research into neuro-ophthalmologic disease mechanisms will provide accurate and specific targeting of important disease mediators through applications of future mAbs. As our understanding of these diseases and the relevant therapeutic targets evolve, we will continue to build on our understanding of how mAbs interfere with disease pathogenesis, and how these changes improve clinical outcomes and quality of life for patients.

Distinct features of B cell receptors in neuromyelitis optica spectrum disorder among CNS inflammatory demyelinating diseases

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) stands out among CNS inflammatory demyelinating diseases (CIDDs) due to its unique disease characteristics, including severe clinical attacks with extensive lesions and its association with systemic autoimmune diseases. We aimed to investigate whether characteristics of B cell receptors (BCRs) differ between NMOSD and other CIDDs using high-throughput sequencing.

METHODS

From a prospective cohort, we recruited patients with CIDDs and categorized them based on the presence and type of autoantibodies: NMOSD with anti-aquaporin-4 antibodies, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) with anti-myelin oligodendrocyte glycoprotein antibodies, double-seronegative demyelinating disease (DSN), and healthy controls (HCs). The BCR features, including isotype class, clonality, somatic hypermutation (SHM), and the third complementarity-determining region (CDR3) length, were analyzed and compared among the different disease groups.

RESULTS

Blood samples from 33 patients with CIDDs (13 NMOSD, 12 MOGAD, and 8 DSN) and 34 HCs were investigated for BCR sequencing. Patients with NMOSD tended to have more activated BCR features compare to the other disease groups. They showed a lower proportion of unswitched isotypes (IgM and IgD) and a higher proportion of switched isotypes (IgG), increased clonality of BCRs, higher rates of SHM, and shorter lengths of CDR3. Notably, advanced age was identified as a clinical factor associated with these activated BCR features, including increased levels of clonality and SHM rates in the NMOSD group. Conversely, no such clinical factors were found to be associated with activated BCR features in the other CIDD groups.

CONCLUSIONS

NMOSD patients, among those with CIDDs, displayed the most pronounced B cell activation, characterized by higher levels of isotype class switching, clonality, SHM rates, and shorter CDR3 lengths. These findings suggest that B cell-mediated humoral immune responses and characteristics in NMOSD patients are distinct from those observed in the other CIDDs, including MOGAD. Age was identified as a clinical factor associated with BCR activation specifically in NMOSD, implying the significance of persistent B cell activation attributed to anti-aquaporin-4 antibodies, even in the absence of clinical relapses throughout an individual's lifetime.

Myelin oligodendrocyte glycoprotein antibody-associated optic neuritis in a post-COVID-19 infection patient

PURPOSE

SARS-CoV-2 viral infection affects multiple systems including the respiratory, gastrointestinal, neurological, cardiac, and ophthalmic systems. We report a case of myelin oligodendrocyte glycoprotein (MOG) related optic neuritis in a SARS-CoV-2 (COVID-19) patient.

METHODS

Case report.

RESULTS

A 36-year-old Malay gentleman with underlying hypertension presented with the first episode of bilateral progressively worsening blurred vision for 1 week associated with retrobulbar pain. There were no other neurological symptoms. He had fever a week before the eye symptoms and tested positive for COVID-19. He received COVID-19 booster vaccine a month before the disease onset. On examination, his vision was hand motion on right eye and 6/18 on left eye. Relative afferent pupillary defect (RAPD) was positive on right eye with abnormal optic nerve function tests. Anterior segments were unremarkable. Fundus examination showed bilateral optic disc swelling. MRI revealed multifocal hyperintense subcortical white matter lesions. Optic nerves appeared normal with no enhancement seen. Blood investigation showed a positive serum MOG antibody. Intravenous methylprednisolone was commenced followed by oral prednisolone after which his vision and ocular symptoms markedly improved. The oral prednisolone was tapered alongside addition of azathioprine. At 1 month, the disease was stable with no recurrence.

CONCLUSION

While optic neuritis has been associated with both COVID-19 infection and vaccination, MOG IgG antibody-mediated optic neuritis is also a possible manifestation. This type of optic neuritis associated with COVID-19 infection does not show a similar pattern of frequent recurrences as seen in non-COVID-19 related optic neuritis.

Patient Pathway to Diagnosis of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD): Findings from a Multinational Survey of 204 Patients

INTRODUCTION

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a rare demyelinating disorder of the central nervous system. Despite increased recognition of MOGAD as a distinct disease and the availability of sensitive methods of MOG antibody testing, diagnostic challenges remain. We conducted a survey to explore the patient experience from the start of symptoms to final MOGAD diagnosis.

METHODS

A 23-question online survey (including multiple-choice and free-text responses) covering symptom history, healthcare interactions and impact of diagnosis was emailed to people living with MOGAD by The MOG Project patient advocacy group. People living with MOGAD could share the survey with their caregivers. Anonymised responses were analysed.

RESULTS

In total, 204 people living with MOGAD or their caregivers from 21 countries completed the survey; most respondents were from North America. Age of symptom onset ranged from 1 to 66 (median 28) years. Symptoms that prompted patients to seek medical care included blurred vision/loss of vision (58.2%), eye pain (35.8%) and difficulty walking (25.4%). Patients most frequently presented to emergency care physicians (38.7%) and primary care doctors (26.0%), with the MOGAD diagnosis most often made by general neurologists (40.4%) or neuro-immunologists (30.0%). Patients saw a median of four doctors before diagnosis, with 26.5% of patients seeing at least six doctors. Although 60.6% of patients received a MOGAD diagnosis within 6 months of experiencing initial health problems, 17.7% experienced a ≥ 5-year delay. More than half of patients (55.4%) received an alternative primary diagnosis before final MOGAD diagnosis. Most respondents (60.6%) reported receiving insufficient information/resources at the time of MOGAD diagnosis. Diagnostic delay was associated with long-term negative consequences for physical health.

CONCLUSION

This survey provides unique insights from people living with MOGAD and their caregivers that could help address the challenges faced in the pathway to final MOGAD diagnosis.

Pathology of myelin oligodendrocyte glycoprotein antibody-associated disease: a comparison with multiple sclerosis and aquaporin 4 antibody-positive neuromyelitis optica spectrum disorders

Myelin oligodendrocyte glycoprotein (MOG) is expressed on the outermost layer of the myelin sheath in the central nervous system. Recently, the clinical concept of MOG antibody-associated disease (MOGAD) was established based on the results of human MOG-transfected cell-based assays which can detect conformation-sensitive antibodies against MOG. In this review, we summarized the pathological findings of MOGAD and discussed the issues that remain unresolved. MOGAD pathology is principally inflammatory demyelination without astrocyte destruction, characterized by perivenous demyelination previously reported in acute disseminated encephalomyelitis and by its fusion pattern localized in both the white and gray matter, but not by radially expanding confluent demyelination typically seen in multiple sclerosis (MS). Some of demyelinating lesions in MOGAD show severe loss of MOG staining compared with those of other myelin proteins, suggesting a MOG-targeted pathology in the disease. Perivascular cuffings mainly consist of macrophages and T cells with CD4-dominancy, which is also different from CD8+ T-cell-dominant inflammation in MS. Compared to aquaporin 4 (AQP4) antibody-positive neuromyelitis optica spectrum disorders (NMOSD), perivenous complement deposition is less common, but can be seen on myelinated fibers and on myelin degradation products within macrophages, resembling MS Pattern II pathology. Thus, the pathogenetic contribution of complements in MOGAD is still debatable. Together, these pathological features in MOGAD are clearly different from those of MS and AQP4 antibody-positive NMOSD, suggesting that MOGAD is an independent autoimmune demyelinating disease entity. Further research is needed to clarify the exact pathomechanisms of demyelination and how the pathophysiology relates to the clinical phenotype and symptoms leading to disability in MOGAD patients.

Two case reports and a systematic review of the literature on adult cerebral cortical encephalitis with anti-myelin oligodendrocyte glycoprotein antibody

Background and purpose

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has gained recognition in recent years as an immune-mediated inflammatory demyelinating disease of the central nervous system. The clinical features and prognosis of MOGAD adult cerebral cortical encephalitis (adult CCE) have not been fully elucidated. This study aims to further characterize the clinical symptoms, magnetic resonance imaging (MRI) findings, and prognosis of CCE with anti-MOG antibody.

Methods

We present two adult cases of CCE with anti-MOG antibody and summarize the clinical symptoms, magnetic resonance imaging (MRI) findings, and prognosis of this phenotype as per a completed systematic review of the literature.

Results

We found a total of 39 cases of MOGAD adult CCE (36% females; average age of onset of 29 years). Among them, 85% had seizure, 82% had headache, 64% had cortical symptoms, 64% had fever, 54% had changes of consciousness, and 38% had ocular symptoms. All cases demonstrated cerebral cortical T2 fluid-attenuated inversion recovery (FLAIR) lesions on MRI. Of the 25 patients (with seizure or not) who had EEG reports, 76% of patients showed abnormal EEG. Cerebrospinal fluid (CSF) white blood cell count of 90% of patients and CSF total protein of 67% of patients were elevated. In 16 patients with available CSF cytology data, 11 (69%) had abnormal cytology findings with monocytic predominance. In the 15 cases for which MOG antibody IgG was tested in both serum and CSF, 14 (93%) demonstrated a higher positive MOG IgG titer in serum than CSF. The majority of patients were treated with immunosuppressive therapy (97% corticosteroids, 15% mycophenolate mofetil, 13% IVIg, 5% azathioprine, and 5% other). The majority of patients had a favorable prognosis after treatment, as exemplified by improved clinical symptoms and imaging. Two patients relapsed.

Conclusions

The clinical presentation and prognosis of adult CCE remain less understood in comparison to more common MOGAD phenotypes. It is important to consider MOGAD as an underlying etiology for adult CCE, as early detection and immunotherapy may improve outcomes.

[Cingulate seizure as a clinical manifestation of anti-myelin oligodendrocyte glycoprotein antibody-positive cerebral cortical encephalitis of two cases]

We report two male patients who had a sensory seizure, which evolved into a focal impaired awareness tonic seizure, and after that, focal to bilateral tonic-clonic seizure. The first case, a 20-year-old man had been treated with steroids for anti-myelin oligodendrocyte glycoprotein (MOG) antibody-positive optic neuritis. His seizure started with abnormal sensation in the little finger of the left hand, which spread to the left upper and then to the left lower limb. The seizure then evolved into tonic seizures of the upper and lower limbs and he finally lost awareness. The second case, a 19-year-old man experienced floating dizziness while walking, followed by numbness and a pain-like electrical shock in the right upper limb. The right arm somatosensory seizure evolved into a right upper and lower limb tonic seizure, which spread to the bilateral limbs, and finally he lost awareness. Symptoms of both patients improved after the treatment with steroids. Both patients shared a similar high-intensity FLAIR lesion in the posterior midcingulate cortex. Both patients were diagnosed with MOG antibody-positive cerebral cortical encephalitis because of a positive titer of anti-MOG antibody in the serum. Several reports showed involvement of the cingulate gyrus in MOG antibody-positive cerebral cortical encephalitis, but only a few reported seizure semiology in detail. The semiology reported here is consistent with that of cingulate epilepsy or the findings of electrical stimulation of the cingulate cortex, namely, somatosensory (electric shock or heat sensation), motor (tonic posture), and vestibular symptoms (dizziness). Cingulate seizures should be suspected when patients show somatosensory seizures or focal tonic seizures. MOG antibody-positive cerebral cortical encephalitis should be considered as one of the differential diagnoses when the young patient shows the unique symptoms of an acute symptomatic cingulate seizure.

Circulating extracellular vesicles promote recovery in a preclinical model of intracerebral hemorrhage

Circulating extracellular vesicles (EVs) are proposed to participate in enhancing pathways of recovery after stroke through paracrine signaling. To verify this hypothesis in a proof-of-concept study, blood-derived allogenic EVs from rats and xenogenic EVs from humans who experienced spontaneous good recovery after an intracerebral hemorrhage (ICH) were administered intravenously to rats at 24 h after a subcortical ICH. At 28 days, both treatments improved the motor function assessment scales score, showed greater fiber preservation in the perilesional zone (diffusion tensor-fractional anisotropy MRI), increased immunofluorescence markers of myelin (MOG), and decreased astrocyte markers (GFAP) compared with controls. Comparison of the protein cargo of circulating EVs at 28 days from animals with good vs. poor recovery showed down-expression of immune system activation pathways (CO4, KLKB1, PROC, FA9, and C1QA) and of restorative processes such as axon guidance (RAC1), myelination (MBP), and synaptic vesicle trafficking (SYN1), which is in line with better tissue preservation. Up-expression of PCSK9 (neuron differentiation) in xenogenic EVs-treated animals suggests enhancement of repair pathways. In conclusion, the administration of blood-derived EVs improved recovery after ICH. These findings open a new and promising opportunity for further development of restorative therapies to improve the outcomes after an ICH.

Proteomics and relationship with axonal pathology in multiple sclerosis: 5-year diffusion tensor imaging study

Blood-based biomarkers can be economic and easily accessible tools for monitoring and predicting disease activity in multiple sclerosis. The objective of this study was to determine the predictive value of a multivariate proteomic assay for concurrent and future microstructural/axonal brain pathology in a longitudinal study of a heterogeneous group of people with multiple sclerosis. A proteomic analysis was obtained on serum samples from 202 people with multiple sclerosis (148 relapsing-remitting and 54 progressive) at baseline and 5-year follow-up. The concentration of 21 proteins related to multiple pathways of multiple sclerosis pathophysiology was derived using Proximity Extension Assay on the Olink platform. Patients were imaged on the same 3T MRI scanner at both timepoints. Тhe rate of whole brain, white matter and grey matter atrophy over the 5-year follow-up was determined using the multi-timepoint Structural Image Evaluation, using Normalisation, of Atrophy algorithms. Lesion burden measures were also assessed. The severity of microstructural axonal brain pathology was quantified using diffusion tensor imaging. Fractional anisotropy and mean diffusivity of normal-appearing brain tissue, normal-appearing white matter, grey matter, T2 and T1 lesions were calculated. Age, sex and body mass index-adjusted step-wise regression models were used. Glial fibrillary acidic protein was the most common and highest-ranked proteomic biomarker associated with greater concurrent microstructural central nervous system alterations (P < 0.001). The rate of whole brain atrophy was associated with baseline levels of glial fibrillary acidic protein, protogenin precursor, neurofilament light chain and myelin oligodendrocyte (P < 0.009), whereas grey matter atrophy was associated with higher baseline neurofilament light chain, higher osteopontin and lower protogenin precursor levels (P < 0.016). Higher baseline glial fibrillary acidic protein level was a significant predictor of future severity of the microstructural CNS alterations as measured by normal-appearing brain tissue fractional anisotropy and mean diffusivity (standardized β = -0.397/0.327, P < 0.001), normal-appearing white matter fractional anisotropy (standardized β = -0.466, P < 0.0012), grey matter mean diffusivity (standardized β = 0.346, P < 0.011) and T2 lesion mean diffusivity (standardized β = 0.416, P < 0.001) at the 5-year follow-up. Serum levels of myelin-oligodendrocyte glycoprotein, neurofilament light chain, contactin-2 and osteopontin proteins were additionally and independently associated with worse concomitant and future axonal pathology. Higher glial fibrillary acidic protein levels were associated with future disability progression (Exp(B) = 8.65, P = 0.004). Multiple proteomic biomarkers are independently associated with greater severity of axonal brain pathology as measured by diffusion tensor imaging in multiple sclerosis. Baseline serum glial fibrillary acidic protein levels can predict future disability progression.

Differential Early Mechanistic Frontal Lobe Responses to Choline Chloride and Soy Isoflavones in an Experimental Model of Fetal Alcohol Spectrum Disorder

Fetal alcohol spectrum disorder (FASD) is the most common preventable cause of neurodevelopmental defects, and white matter is a major target of ethanol neurotoxicity. Therapeutic interventions with choline or dietary soy could potentially supplement public health preventive measures. However, since soy contains abundant choline, it would be important to know if its benefits are mediated by choline or isoflavones. We compared early mechanistic responses to choline and the Daidzein+Genistein (D+G) soy isoflavones in an FASD model using frontal lobe tissue to assess oligodendrocyte function and Akt-mTOR signaling. Long Evans rat pups were binge administered 2 g/Kg of ethanol or saline (control) on postnatal days P3 and P5. P7 frontal lobe slice cultures were treated with vehicle (Veh), Choline chloride (Chol; 75 µM), or D+G (1 µM each) for 72 h without further ethanol exposures. The expression levels of myelin oligodendrocyte proteins and stress-related molecules were measured by duplex enzyme-linked immunosorbent assays (ELISAs), and mTOR signaling proteins and phosphoproteins were assessed using 11-plex magnetic bead-based ELISAs. Ethanol's main short-term effects in Veh-treated cultures were to increase GFAP and relative PTEN phosphorylation and reduce Akt phosphorylation. Chol and D+G significantly modulated the expression of oligodendrocyte myelin proteins and mediators of insulin/IGF-1-Akt-mTOR signaling in both control and ethanol-exposed cultures. In general, the responses were more robust with D+G; the main exception was that RPS6 phosphorylation was significantly increased by Chol and not D+G. The findings suggest that dietary soy, with the benefits of providing complete nutrition together with Choline, could be used to help optimize neurodevelopment in humans at risk for FASD.

Biomarkers for parkinsonian disorders in CNS-originating EVs: promise and challenges

Extracellular vesicles (EVs), including exosomes, microvesicles, and oncosomes, are nano-sized particles enclosed by a lipid bilayer. EVs are released by virtually all eukaryotic cells and have been shown to contribute to intercellular communication by transporting proteins, lipids, and nucleic acids. In the context of neurodegenerative diseases, EVs may carry toxic, misfolded forms of amyloidogenic proteins and facilitate their spread to recipient cells in the central nervous system (CNS). CNS-originating EVs can cross the blood-brain barrier into the bloodstream and may be found in other body fluids, including saliva, tears, and urine. EVs originating in the CNS represent an attractive source of biomarkers for neurodegenerative diseases, because they contain cell- and cell state-specific biological materials. In recent years, multiple papers have reported the use of this strategy for identification and quantitation of biomarkers for neurodegenerative diseases, including Parkinson's disease and atypical parkinsonian disorders. However, certain technical issues have yet to be standardized, such as the best surface markers for isolation of cell type-specific EVs and validating the cellular origin of the EVs. Here, we review recent research using CNS-originating EVs for biomarker studies, primarily in parkinsonian disorders, highlight technical challenges, and propose strategies for overcoming them.

Myelin Oligodendrocyte Glycoprotein as an Autoantigen in Inflammatory Demyelinating Diseases of the Central Nervous System

Demyelinating diseases of the central nervous system are caused by an autoimmune attack on the myelin sheath surrounding axons. Myelin structural proteins become antigenic, leading to the development of myelin lesions. The use of highly specialized laboratory diagnostic techniques for identification of specific antibodies directed against myelin components can significantly improve diagnostic approaches. Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) currently includes demyelinating syndromes with known antigens. Based on the demonstrated pathogenic role of human IgG against MOG, MOGAD was classified as a distinct nosological entity. However, generation of multiple MOG isoforms by alternative splicing hinders antigen detection even with the most advanced immunofluorescence techniques. On the other hand, MOG conformational changes ensure the structural integrity of other myelin proteins and maintain human-specific mechanisms of immune autotolerance.

Clinical features of the first attack with leukodystrophy‐like phenotype in children with myelin oligodendrocyte glycoprotein antibody‐associated disorders

BACKGROUND

Myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD) is identified autoimmune disorder with a predominance in paediatric patients, and the disease spectrum has expanded with clinical and radiological patterns. The aim of the study was to describe the clinical characteristics of the first attack with leukodystrophy-like phenotype with MOGAD in children.

METHODS

Patients hospitalized at the Children's Hospital of Chongqing Medical University from June 2017 to October 2021 with positive MOG antibodies and phenotype of leukodystrophy-like (symmetric white matter lesions) were retrospectively analyzed. Cell-based assays (CBAs) were used to test MOG antibodies.

RESULTS

Four cases from 143 MOGAD patients were recruited, with two females and two males. The age of onset is all under 6 years old. At the last follow-up, four cases exhibited a monophasic course, including ADEM in three patients and encephalitis in one patient. The mean EDSS score at onset was 4.62 ± 2.93, and the modified Rankin score (mRS) was 3.00 ± 1.82. First-attack symptoms include fever, headache, vomiting, seizure, loss of consciousness, emotional and behavioural disorder, and ataxia. The brain MRI showed prominent extensive and essentially symmetric distribution lesions in the white matter. All patients showed clinical and partial radiological improvement after intravenous immunoglobulin and/or glucocorticoid treatment.

CONCLUSION

The first attack with MOGAD onset of leukodystrophy-like phenotype was more frequently seen in younger children than other phenotype patients. The patients may show impressive neurologic disorders, but most patients who receive immunotherapy have a good prognosis.

The Potential Pathogenicity of Myelin Oligodendrocyte Glycoprotein Antibodies in the Optic Pathway

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an acquired inflammatory demyelinating disease with optic neuritis (ON) as the most frequent clinical symptom. The hallmark of the disease is the presence of autoantibodies against MOG (MOG-IgG) in the serum of patients. Whereas the role of MOG in the experimental autoimmune encephalomyelitis animal model is well-established, the pathogenesis of the human disease and the role of human MOG-IgG is still not fully clear.

EVIDENCE ACQUISITION

PubMed was searched for the terms "MOGAD," "optic neuritis," "MOG antibodies," and "experimental autoimmune encephalomyelitis" alone or in combination, to find articles of interest for this review. Only articles written in English language were included and reference lists were searched for further relevant papers.

RESULTS

B and T cells play a role in the pathogenesis of human MOGAD. The distribution of lesions and their development toward the optic pathway is influenced by the genetic background in animal models. Moreover, MOGAD-associated ON is frequently bilateral and often relapsing with generally favorable visual outcome. Activated T-cell subsets create an inflammatory environment and B cells are necessary to produce autoantibodies directed against the MOG protein. Here, pathologic mechanisms of MOG-IgG are discussed, and histopathologic findings are presented.

CONCLUSIONS

MOGAD patients often present with ON and harbor antibodies against MOG. Furthermore, pathogenesis is most likely a synergy between encephalitogenic T and antibody producing B cells. However, to which extent MOG-IgG are pathogenic and the exact pathologic mechanism is still not well understood.

Unilateral Autoimmune Encephalitis: A Case Report on a Rare Manifestation of Myelin Oligodendrocyte Glycoprotein Antibody Disease

Myelin oligodendrocyte glycoprotein (MOG)-associated disease (MOGAD) is a rare, antibody-mediated inflammatory demyelinating disorder of the central nervous system (CNS) that has varying phenotypes. FLAIR (fluid-attenuated inversion recovery)-hyperintense Lesions in Anti-MOG-associated Encephalitis with Seizures (FLAMES) is a much rarer manifestation of cortical encephalitis encountered in MOGAD. We report a rare case of a nine-year-old girl who presented with a drop in her academic performance and right-sided Epilepsia partialis continua. Magnetic resonance imaging (MRI) of the brain detected evidence for unilateral (left) cortical encephalitis with peri-ictal juxtacortical edema. An electroencephalogram revealed a hemi-generalized poly spike and wave discharges in the left hemisphere, several of which correlated with myoclonic jerks. The cerebrospinal fluid (CSF) analysis was normal. Autoimmune workup resulted in a positive serum MOG-immunoglobulin G (IgG), which confirmed the diagnosis of FLAMES. The child showed an excellent clinical response to intravenous methylprednisolone and intravenous immunoglobulins therapy.

Correlations between single nucleotide polymorphisms in obsessive-compulsive disorder with the clinical features or response to therapy

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder, in which the patient endures intrusive thoughts or is compelled to perform repetitive or ritualized actions. Many cases of OCD are considered to be familial or heritable in nature. It has been shown that a variety of internal and external risk factors are involved in the pathogenesis of OCD. Among the internal factors, genetic modifications play a critical role in the pathophysiological process. Despite many investigations performed to determine the candidate genes, the precise genetic factors involved in the disease remain largely undetermined. The present review summarizes the single nucleotide polymorphisms that have been proposed to be associated with OCD symptoms, early onset disease, neuroimaging results, and response to therapy. This information could help us to draw connections between genetics and OCD symptoms, better characterize OCD in individual patients, understand OCD prognosis, and design more targeted personalized treatment approaches.

Clinical features of patients with MOG-IgG associated disorders and analysis of the relationship between fibrinogen-to-albumin ratio and the severity at disease onset

Objective

The study aimed to investigate the differences in clinical features between pediatric and adult patients with first-episode MOG-IgG associated disorders (MOGAD) and evaluate the relationship between the fibrinogen-to-albumin ratio (FAR) and the severity of neurological deficits at disease onset.

Methods

We retrospectively collected and analyzed biochemical test results, imaging characteristics, clinical manifestations, expanded disability status scale (EDSS) score, and FAR. The Spearman correlation analysis and logistic regression models were used to examine the association between FAR and severity. Receiver operating characteristic (ROC) curve analysis was to analyze the predictive ability of FAR for the severity of neurological deficits.

Results

Fever (50.0%), headache (36.1%), and blurred vision (27.8%) were the most common clinical manifestations in the pediatric group (<18 years old). However, in the adult group (≥18 years old), the most common symptoms were blurred vision (45.7%), paralysis (37.0%), and paresthesia (32.6%). Fever was more common in the pediatric group, while paresthesia was more common in the adult patients, with all differences statistically significant (P < 0.05). The most frequent clinical phenotype in the pediatric group was acute disseminated encephalomyelitis (ADEM; 41.7%), whereas optic neuritis (ON; 32.6%) and transverse myelitis (TM; 26.1%) were more common in the adult group. The differences in clinical phenotype between the two groups were statistically significant (P < 0.05). In both pediatric and adult patients, cortical/subcortical and brainstem lesions were the most common lesions on cranial magnetic resonance imaging (MRI), whereas, for spinal MRI, cervical and thoracic spinal cord lesions were the most commonly observed. According to binary logistic regression analysis, FAR was an independent risk factor for the severity of neurological deficits (odds ratio = 1.717; 95% confidence interval = 1.191-2.477; P = 0.004). FAR (r = 0.359, P = 0.001) was positively correlated with the initial EDSS score. The area under the ROC curve was 0.749.

Conclusion

The current study found age-dependent phenotypes in MOGAD patients as ADEM was more commonly observed in patients < 18 years old, while ON and TM were more frequently found in patients ≥18 years old. A high FAR level was an independent indicator for more severe neurological deficits at disease onset in patients with a first episode of MOGAD.

Pathophysiology of myelin oligodendrocyte glycoprotein antibody disease

Myelin Oligodendrocyte Glycoprotein Antibody Disease (MOGAD) is a spectrum of diseases, including optic neuritis, transverse myelitis, acute disseminated encephalomyelitis, and cerebral cortical encephalitis. In addition to distinct clinical, radiological, and immunological features, the infectious prodrome is more commonly reported in MOGAD (37-70%) than NMOSD (15-35%). Interestingly, pediatric MOGAD is not more aggressive than adult-onset MOGAD, unlike in multiple sclerosis (MS), where annualized relapse rates are three times higher in pediatric-onset MS. MOGAD pathophysiology is driven by acute attacks during which T cells and MOG antibodies cross blood brain barrier (BBB). MOGAD lesions show a perivenous confluent pattern around the small veins, lacking the radiological central vein sign. Initial activation of T cells in the periphery is followed by reactivation in the subarachnoid/perivascular spaces by MOG-laden antigen-presenting cells and inflammatory CSF milieu, which enables T cells to infiltrate CNS parenchyma. CD4+ T cells, unlike CD8+ T cells in MS, are the dominant T cell type found in lesion histology. Granulocytes, macrophages/microglia, and activated complement are also found in the lesions, which could contribute to demyelination during acute relapses. MOG antibodies potentially contribute to pathology by opsonizing MOG, complement activation, and antibody-dependent cellular cytotoxicity. Stimulation of peripheral MOG-specific B cells through TLR stimulation or T follicular helper cells might help differentiate MOG antibody-producing plasma cells in the peripheral blood. Neuroinflammatory biomarkers (such as MBP, sNFL, GFAP, Tau) in MOGAD support that most axonal damage happens in the initial attack, whereas relapses are associated with increased myelin damage.

Case report: MOG-IgG-associated encephalitis with Epstein-Barr virus infection and Alzheimer's pathologic change in cerebrospinal fluid

Immunoglobulin G antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG) associated disease is a rare, demyelinated disease in the central nerve system (CNS) predominately involving optic nerve, spinal cord, and brain leading to optic neuritis (ON), transverse myelitis (TM), encephalitis. The phenotype of MOG-IgG-associated encephalitis is similar to acute disseminated encephalomyelitis (ADEM) presenting with seizures, abnormal behavioral and psychological symptoms, and cognitive impairment. A few brain biopsies show multiple sclerosis (MS) pattern histopathology with T cells, macrophages, and complement activation. To date, how MOG-IgG is produced is unknown. Herein, we report a case of a 32-year-old male with MOG-IgG-associated encephalitis presenting MOG-IgG in cerebrospinal fluid (CSF) but seronegative, as well as Epstein-Barr virus (EBV) infection and Alzheimer's pathologic change in CSF (Aβ42 = 317 pg/ml, T-Tau = 538 pg/ml, p-Tau =10.09 pg/ml). With a combination treatment of administering intravenous immunoglobulin (0.4 mg/kg/d, 5 days) with a low dose of methylprednisolone (80 mg/d, 5 days) and rituximab (100 mg/week, 3 weeks), the patient recovered significantly after 3 months follow-up. This case provides us with new thoughts into the production of MOG-IgG and the possible pathologic mechanism of MOG-IgG-associated disease (MOG-AD) and simultaneously further confirms the interaction between EBV and changes of CSF biomarkers of Alzheimer's disease (AD).

Glial cells and neurologic autoimmune disorders

Neurologic autoimmune disorders affect people's physical and mental health seriously. Glial cells, as an important part of the nervous system, play a vital role in the occurrence of neurologic autoimmune disorders. Glial cells can be hyperactivated in the presence of autoantibodies or pathological changes, to influence neurologic autoimmune disorders. This review is mainly focused on the roles of glial cells in neurologic autoimmune disorders and the influence of autoantibodies produced by autoimmune disorders on glial cells. We speculate that the possibility of glial cells might be a novel way for the investigation and therapy of neurologic autoimmune disorders.

Central nervous system (CNS) inflammatory demyelinating diseases (IDDs) associated with COVID-19: A case series and review

BACKGROUND

Over the past two years, SARS-CoV-2 has frequently been documented with various post and para-infectious complications, including cerebrovascular, neuromuscular, and some demyelinating conditions such as acute disseminated encephalomyelitis (ADEM). We report two rare neurological manifestations post-COVID-19 infection; multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Further, we reviewed other CNS inflammatory demyelinating diseases (IDDs) associated with SARS-CoV-2, including optic neuritis (ON) and neuromyelitis optica spectrum disorders (NMOSD).

METHODS

A descriptive analysis and literature search of Google Scholar and PubMed was conducted by two independent reviewers from December 1st, 2019, to March 30th, 2022, and included all the case studies of MS, MOGAD, NMOSD, and ON associated with COVID-19 infection.

CASE PRESENTATIONS

Case 1 (MS) was a 24-year-old female with paresthesia and bilateral weakness one week after COVID-19 symptom onset who showed demyelinating plaques and 12 isolated oligoclonal bands (OCBs). Case 2 (MOGAD) was a 41-year-old male with encephalomyelitis 16 days after COVID-19, who later developed MOG-antibody-associated optic neuritis.

RESULTS

Out of 18 cases, NMOSD was the most common post-COVID manifestation (7, 39%), followed by MOGAD (5, 28%), MS (4, 22%), and isolated ON (2, 11%). The median duration between the onset of COVID-19 symptom onset and neurological symptoms was 14 days. 61% of these were male, with a mean age of 35 years. IVMP was the treatment of choice, and nearly all patients made a full recovery, with zero fatalities.

CONCLUSIONS

Although these neurological sequelae are few, physicians must be cognizant of their underlying pathophysiology and associated clinical and neuro-diagnostic findings when treating COVID-19 patients with atypical presentations.

Update in autoimmune and paraneoplastic myelopathies: Newly described antigen targets and antibody testing

Myelopathy is an increasingly recognized presentation of many antibody-mediated neuroinflammatory disorders. While specific features of certain autoimmune myelopathies such as aquaporin-4 antibody associated neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein associated disorder (MOGAD) are well-characterized, other less commonly seen antibody-associated myelopathies are not as well-defined. These include but are not limited to, Hu/ANNA1, anti-glial fibrillary acidic protein (GFAP), anti-CV2/collapsin response mediator protein (CRMP5), and amphiphysin. Here, we review the mentioned more common antibody mediated myelopathies as well those that as less common, followed by a review of differentials that may mimic these disorders.

Coexistence of Myelin Oligodendrocyte Glycoprotein Immunoglobulin G and Neuronal or Glial Antibodies in the Central Nervous System: A Systematic Review

Background: Myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) has been considered a diagnostic marker for patients with demyelinating disease, termed “MOG-IgG associated disorder” (MOGAD). Recently, the coexistence of MOG-IgG and other neuronal or glial antibodies has attracted extensive attention from clinicians. In this article, we systematically review the characteristics of MOG-IgG-related antibody coexistence syndrome. Methods: Two authors independently searched PubMed for relevant studies published before October 2021. We also manually searched the references of each related article. The appropriateness of the included studies was assessed by reading the titles, abstracts, and full texts if necessary. Results: Thirty-five relevant publications that met our inclusion criteria were finally included, of which fourteen were retrospective studies and twenty-one were case reports. A total of 113 patients were reported to show the coexistence of MOG-IgG and neuronal or glial antibodies. Additionally, 68.14% of patients were double positive for MOG-IgG and N-Methyl-D-Aspartate Receptor-IgG (NMDAR-IgG), followed by 23.01% of patients who were double positive for MOG-IgG and aquaporin4-IgG (AQP4-IgG). Encephalitis was the predominant phenotype when MOG-IgG coexisted with NMDAR-IgG, probably accompanied by imaging features of demyelination. Patients with dual positivity for MOG-IgG and AQP4-IgG experienced more severe disease and more frequent relapses. The coexistence of MOG-IgG and antibodies other than NMDAR-IgG and AQP4-IgG was extremely rare, and the clinical presentations were diverse and atypical. Except for patients who were double positive for MOG-IgG and AQP4-IgG, most patients with multiple antibodies had a good prognosis. Conclusions: MOG-IgG may coexist with neuronal or glial antibodies. Expanded screening for neuronal or glial antibodies should be performed in patients with atypical clinical and radiological features.

Developmental Cues and Molecular Drivers in Myelinogenesis: Revisiting Early Life to Re-Evaluate the Integrity of CNS Myelin

The mammalian central nervous system (CNS) coordinates its communication through saltatory conduction, facilitated by myelin-forming oligodendrocytes (OLs). Despite the fact that neurogenesis from stem cell niches has caught the majority of attention in recent years, oligodendrogenesis and, more specifically, the molecular underpinnings behind OL-dependent myelinogenesis, remain largely unknown. In this comprehensive review, we determine the developmental cues and molecular drivers which regulate normal myelination both at the prenatal and postnatal periods. We have indexed the individual stages of myelinogenesis sequentially; from the initiation of oligodendrocyte precursor cells, including migration and proliferation, to first contact with the axon that enlists positive and negative regulators for myelination, until the ultimate maintenance of the axon ensheathment and myelin growth. Here, we highlight multiple developmental pathways that are key to successful myelin formation and define the molecular pathways that can potentially be targets for pharmacological interventions in a variety of neurological disorders that exhibit demyelination.

Monoclonal Antibody Therapies Beyond Complement for NMOSD and MOGAD

Aquaporin-4 (AQP4)-IgG seropositive neuromyelitis optica spectrum disorders (AQP4-IgG seropositive NMOSD) and myelin oligodendrocyte glycoprotein (MOG)-IgG-associated disease (MOGAD) are inflammatory demyelinating disorders distinct from each other and from multiple sclerosis (MS).While anti-CD20 treatments can be used to treat MS and AQP4-IgG seropositive NMOSD, some MS medications are ineffective or could exacerbate AQP4-IgG seropositive NMOSD including beta-interferons, natalizumab, and fingolimod. AQP4-IgG seropositive NMOSD has a relapsing course in most cases, and preventative maintenance treatments should be started after the initial attack. Rituximab, eculizumab, inebilizumab, and satralizumab all have class 1 evidence for use in AQP4-IgG seropositive NMOSD, and the latter three have been approved by the US Food and Drug Administration (FDA). MOGAD is much more likely to be monophasic than AQP4-IgG seropositive NMOSD, and preventative therapy is usually reserved for those who have had a disease relapse. There is a lack of any class 1 evidence for MOGAD preventative treatment. Observational benefit has been suggested from oral immunosuppressants, intravenous immunoglobulin (IVIg), rituximab, and tocilizumab. Randomized placebo-controlled trials are urgently needed in this area.

Clinical Features and Imaging Findings of Myelin Oligodendrocyte Glycoprotein-IgG-Associated Disorder (MOGAD)

Myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD) is a nervous system (NS) demyelination disease and a newly recognized distinct disease complicated with various diseases or symptoms; however, MOGAD was once considered a subset of neuromyelitis optica spectrum disorder (NMOSD). The detection of MOG-IgG has been greatly improved by the cell-based assay test method. In one study, 31% of NMOSD patients with negative aquaporin-4 (AQP-4) antibody were MOG-IgG positive. MOGAD occurs in approximately the fourth decade of a person’s life without a markedly female predominance. Usually, optic neuritis (ON), myelitis or acute disseminated encephalomyelitis (ADEM) encephalitis are the typical symptoms of MOGAD. MOG-IgG have been found in patients with peripheral neuropathy, teratoma, COVID-19 pneumonia, etc. Some studies have revealed the presence of brainstem lesions, encephalopathy or cortical encephalitis. Attention should be given to screening patients with atypical symptoms. Compared to NMOSD, MOGAD generally responds well to immunotherapy and has a good functional prognosis. Approximately 44-83% of patients undergo relapsing episodes within 8 months, which mostly involve the optic nerve, and persistently observed MOG-IgG and severe clinical performance may indicate a polyphasic course of illness. Currently, there is a lack of clinical randomized controlled trials on the treatment and prognosis of MOGAD. The purpose of this review is to discuss the clinical manifestations, imaging features, outcomes and prognosis of MOGAD.

Orbital Inflammation in Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease: A Case Report and Review of the Literature

BACKGROUND

To present 2 patients with myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease with unilateral orbital inflammation, optic nerve head edema, and abnormalities of the optic nerve and nerve sheath on imaging. We review the most current literature on this important and uncommon clinical phenotype.

METHODS

A case report of 2 patients and a comprehensive review of the relevant literature on orbital inflammation in MOG antibody-associated disease (MOG-AD).

RESULTS

Two patients presented with decreased vision and unilateral orbital inflammation. Both had optic nerve head edema and abnormalities of the optic nerve and nerve sheath on imaging. The patients were treated with immunosuppressants and had improvement of vision changes as well as their orbital inflammatory signs. MOG antibody was positive in high titers in both patients. Only 3 other cases of orbital inflammation associated with MOG antibody have been described. In all cases, orbital signs responded rapidly to intravenous methylprednisolone, but the improvement in visual acuity was variable and less robust.

CONCLUSION

Orbital inflammation is a unique and underrecognized phenotype of MOG-AD with only a few reports in the literature. In patients who present with vision loss and orbital inflammation, MOG-AD should be considered in the differential.

Uncommon inflammatory/immune-related myelopathies

The differential diagnosis for immune-mediated myelopathies is broad. Although clinical manifestations overlap, certain presentations are suggestive of a particular myelopathy etiology. Spine MRI lesion characteristics including the length and location, and the pattern of gadolinium enhancement, help narrow the differential diagnosis and exclude an extrinsic compressive cause. The discovery of specific antibodies that serve as biomarkers of myelitis such as aquaporin-4-IgG and myelin-oligodendrocyte -glycoprotein-IgG (MOG-IgG), has improved our understanding of myelitis pathophysiology and facilitated diagnosis. In this review we will focus on the pathophysiology, clinical presentation, imaging findings and treatment and outcomes of uncommon immune-mediated myelopathies.

Demyelination of the Optic Nerve: An Underlying Factor in Glaucoma?

Neurodegenerative disorders are characterized by typical neuronal degeneration and axonal loss in the central nervous system (CNS). Demyelination occurs when myelin or oligodendrocytes experience damage. Pathological changes in demyelination contribute to neurodegenerative diseases and worsen clinical symptoms during disease progression. Glaucoma is a neurodegenerative disease characterized by progressive degeneration of retinal ganglion cells (RGCs) and the optic nerve. Since it is not yet well understood, we hypothesized that demyelination could play a significant role in glaucoma. Therefore, this study started with the morphological and functional manifestations of demyelination in the CNS. Then, we discussed the main mechanisms of demyelination in terms of oxidative stress, mitochondrial damage, and immuno-inflammatory responses. Finally, we summarized the existing research on the relationship between optic nerve demyelination and glaucoma, aiming to inspire effective treatment plans for glaucoma in the future.

An insight into the role of liposomal therapeutics in the reversion of Multiple Sclerosis

INTRODUCTION

Multiple Sclerosis (MS), as an autoimmune disease, has complicated immunopathology, which makes its management relevant to various factors. Novel pharmaceutical vehicles, especially liposomes, can support efficacious handling of this disease both in early detection and prognosis and also in a therapeutic manner. The most well-known trigger of MS onset is the predominance of cellular to humoral immunity and enhancement of inflammatory cytokines level. The installation of liposomes as nanoparticles to control this disease holds great promise up to now.

AREAS COVERED

Various types of liposomes with different properties and purposes have been formulated and targeted immune cells with their surface manipulations. They may be encapsulated with anti-inflammatory, MS-related therapeutics, or immunodominant myelin-specific peptides for attaining a higher therapeutic efficacy of the drugs or tolerance induction. Cationic liposomes are also highly applicable for gene delivery of the anti-inflammatory cytokines or silencing the inflammatory cytokines. Liposomes have also been used as biotools for comprehending MS pathomechanisms or as diagnostic agents.

EXPERT OPINION

The efforts to manage MS through nanomedicine, especially liposomal therapeutics, pave a new avenue to a high-throughput medication of this autoimmune disease and their translation to the clinic in the future for overcoming the challenges that MS patients confront.

GRP78 Antibodies Are Associated With Blood-Brain Barrier Breakdown in Anti-Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder

Background and Objectives

To analyze (1) the effect of immunoglobulin G (IgG) from patients with anti–myelin oligodendrocyte glycoprotein antibody (MOG-Ab)–associated disorder on the blood-brain barrier (BBB) endothelial cells and (2) the positivity of glucose-regulated protein 78 (GRP78) antibodies in MOG-Ab–associated disorders.

Methods

IgG was purified from sera with patients with MOG-Ab–associated disorder in the acute phase (acute MOG, n = 15), in the stable stage (stable MOG, n = 14), healthy controls (HCs, n = 9), and disease controls (DCs, n = 27). Human brain microvascular endothelial cells (BMECs) were incubated with IgG, and the number of nuclear NF-κB p65-positive cells in BMECs using high-content imaging system and the quantitative messenger RNA change in gene expression over the whole transcriptome using RNA-seq were analyzed. GRP78 antibodies from patient IgGs were detected by Western blotting.

Results

IgG in the acute MOG group significantly induced the nuclear translocation of NF-κB and increased the vascular cell adhesion molecule 1/intercellular adhesion molecule 1 expression/permeability of 10-kDa dextran compared with that from the stable MOG and HC/DC groups. RNA-seq and pathway analysis revealed that NF-κB signaling and oxidative stress (NQO1) play key roles. The NQO1 and Nrf2 protein amounts were significantly decreased after exposure to IgG in the acute MOG group. The rate of GRP78 antibody positivity in the acute MOG group (10/15, 67% [95% confidence interval, 38%–88%]) was significantly higher than that in the stable MOG group (5/14, 36% [13%–65%]), multiple sclerosis group (4/29, 14% [4%–32%]), the DCs (3/27, 11% [2%–29%]), or HCs (0/9, 0%). Removal of GRP78 antibodies from MOG-IgG reduced the effect on NF-κB nuclear translocation and increased permeability.

Discussion

GRP78 antibodies may be associated with BBB dysfunction in MOG-Ab–associated disorder.

The extracellular region of bovine milk butyrophilin exhibits closer structural similarity to human myelin oligodendrocyte glycoprotein than to immunological BTN family receptors

Bovine butyrophilin (BTN1A1) is an abundant type I transmembrane glycoprotein exposed on the surface of milk fat globules. We have solved the crystal structure of its extracellular region via multiple wavelength anomalous dispersion after incorporation of selenomethionine into the bacterially produced protein. The butyrophilin ectodomain exhibits two subdomains with immunoglobulin fold, each comprising a β-sandwich with a central disulfide bridge as well as one N-linked glycosylation. The fifth Cys residue at position 193 is unpaired and prone to forming disulfide crosslinks. The apparent lack of a ligand-binding site or receptor activity suggests a function predominantly as hydrophilic coat protein to prevent coagulation of the milk fat droplets. While there is less structural resemblance to members of the human butyrophilin family such as BTN3A, which play a role as immune receptors, the N-terminal bovine butyrophilin subdomain shows surprising similarity to the human myelin oligodendrocyte glycoprotein, a protein exposed on the surface of myelin sheaths. Thus, our study lends structural support to earlier hypotheses of a correlation between the consumption of cow milk and prevalence of neurological autoimmune diseases and may offer guidance for the breeding of cattle strains that express modified butyrophilin showing less immunological cross-reactivity.

Myelin-oligodendrocyte glycoprotein antibody-associated disease

Myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a recently identified autoimmune disorder that presents in both adults and children as CNS demyelination. Although there are clinical phenotypic overlaps between MOGAD, multiple sclerosis, and aquaporin-4 antibody-associated neuromyelitis optica spectrum disorder (NMOSD) cumulative biological, clinical, and pathological evidence discriminates between these conditions. Patients should not be diagnosed with multiple sclerosis or NMOSD if they have anti-MOG antibodies in their serum. However, many questions related to the clinical characterisation of MOGAD and pathogenetic role of MOG antibodies are still unanswered. Furthermore, therapy is mainly based on standard protocols for aquaporin-4 antibody-associated NMOSD and multiple sclerosis, and more evidence is needed regarding how and when to treat patients with MOGAD.

Meningeal B Cell Clusters Correlate with Submeningeal Pathology in a Natural Model of Multiple Sclerosis

Multiple sclerosis (MS) is an idiopathic demyelinating disease in which meningeal inflammation correlates with accelerated disease progression. The study of meningeal inflammation in MS has been limited because of constrained access to MS brain/spinal cord specimens and the lack of experimental models recapitulating progressive MS. Unlike induced models, a spontaneously occurring model would offer a unique opportunity to understand MS immunopathogenesis and provide a compelling framework for translational research. We propose granulomatous meningoencephalomyelitis (GME) as a natural model to study neuropathological aspects of MS. GME is an idiopathic, progressive neuroinflammatory disease of young dogs with a female bias. In the GME cases examined in this study, the meninges displayed focal and disseminated leptomeningeal enhancement on magnetic resonance imaging, which correlated with heavy leptomeningeal lymphocytic infiltration. These leptomeningeal infiltrates resembled tertiary lymphoid organs containing large B cell clusters that included few proliferating Ki67+ cells, plasma cells, follicular dendritic/reticular cells, and germinal center B cell-like cells. These B cell collections were confined in a specialized network of collagen fibers associated with the expression of the lympho-organogenic chemokines CXCL13 and CCL21. Although neuroparenchymal perivascular infiltrates contained B cells, they lacked the immune signature of aggregates in the meningeal compartment. Finally, meningeal B cell accumulation correlated significantly with cortical demyelination reflecting neuropathological similarities to MS. Hence, during chronic neuroinflammation, the meningeal microenvironment sustains B cell accumulation that is accompanied by underlying neuroparenchymal injury, indicating GME as a novel, naturally occurring model to study compartmentalized neuroinflammation and the associated pathology thought to contribute to progressive MS.

Targeted Expression of Myelin Autoantigen in the Periphery Induces Antigen-Specific T and B Cell Tolerance and Ameliorates Autoimmune Disease

There is a great interest in developing antigen-specific therapeutic approaches for the treatment of autoimmune diseases without compromising normal immune function. The key challenges are to control all antigen-specific lymphocyte populations that contribute to pathogenic inflammatory processes and to provide long-term protection from disease relapses. Here, we show that myelin oligodendrocyte glycoprotein (MOG)-specific tolerance can be established by ectopic expression of MOG in the immune organs. Using transgenic mice expressing MOG-specific CD4, CD8, and B cell receptors, we show that MOG expression in the bone marrow cells results in impaired development of MOG-specific lymphocytes. Ectopic MOG expression has also resulted in long-lasting protection from MOG-induced autoimmunity. This finding raises hope that transplantation of autoantigen-expressing bone marrow cells as a therapeutic strategy for specific autoantigen-driven autoimmune diseases.

The Clinical, Radiologic, and Prognostic Differences Between Pediatric and Adult Patients With Myelin Oligodendrocyte Glycoprotein Antibody-Associated Encephalomyelitis

Purpose: To evaluate the clinical differences between pediatric and adult patients with myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM).

Methods: We retrospectively reviewed the clinical features of pediatric and adult patients with MOG-EM in our center between November 2015 and October 2020.

Results: Twenty-eight pediatric patients and 25 adults were admitted to our study. Bilateral optic neuritis (BON) was the most common initial phenotype in the pediatric group but less common in the adult group (28.57 vs. 0%, p = 0.0119). Almost half of the adult patients presented with neuromyelitis optica spectrum disease (NMOSD), which was less prevalent among the pediatrics (48 vs. 21.43%, p = 0.0414). Visual impairment was the most common symptom in both groups during the initial attack (pediatric group, 39.29%; adult group, 64%) and throughout the full course (pediatric group, 57.14%; adult group, 72%). More pediatric patients suffered from fever than adult patients at onset (pediatric group, 28.57%; adult group, 4%; p = 0.0442) and throughout the full course (pediatric group, 39.29%; adult group, 12%; p = 0.0245). Multiple patchy lesions in subcortical white matter (pediatric group, 40.74%; adult group, 45%), periventricular (pediatric group, 25.93%; adult group, 35%), infratentorial (pediatric group, 18.52%; adult group, 30%) and deep gray matter (pediatric group, 25.93%; adult group, 20%) were frequent in all cases, no significant difference was found between the two groups, while bilateral optic nerve involvement was more frequent in pediatric group (61.54 vs. 14.29%, p = 0.0042) and unilateral optic nerve involvement was higher in adult group (64.29 vs. 15.38%, p = 0.0052). At the last follow-up, adult patients had a higher average EDSS score (median 1.0, range 0–3) than pediatrics (median 0.0, range 0–3), though not significant (p = 0.0752). Patients aged 0–9 years (61.54%) and 10–18 years (70%), and patients presenting with encephalitis/meningoencephalitis (100%) and ADEM (75%) were more likely to recover fully.

Conclusions: Visual impairment was the dominant symptom in both pediatric and adult patients, while fever was more frequent in pediatric patients. Data suggested that BON and bilateral optic nerve involvement were more common in pediatric cases whereas NMOSD and unilateral optic nerve involvement were more prevalent in adults. The younger patients and patients presenting with encephalitis/meningoencephalitis and ADEM tended to recover better.

Myelin oligodendrocyte glycoprotein antibody-associated optic neuritis in a COVID-19 patient: A case report

RATIONALE

Coronavirus disease 2019 (COVID-19) has spread worldwide. It involves multiple organs of infected individuals and encompasses diverse clinical manifestations. We report a case of acute optic neuritis (ON) associated with myelin oligodendrocyte glycoprotein (MOG) antibody possibly induced by COVID-19.

PATIENT CONCERNS

A 47-year-old man presented to our clinic with left eye pain and vision loss. Magnetic resonance imaging of the orbit revealed the bilateral high intensity of the optic nerve sheaths. He tested positive for COVID-19 by polymerase chain reaction (PCR) testing on the day of admission but he had no signs of respiratory illness. Laboratory testing revealed that MOG immunoglobulin G (MOG IgG) was positive, but other antibodies including aquaporin-4 were negative.

DIAGNOSIS

The patient was diagnosed with MOG antibody-positive acute ON possibly induced by COVID-19.

INTERVENTIONS

Steroid pulse therapy consisting of methylprednisolone 1 g/day for a total of 3 days, followed by an oral prednisolone taper was performed.

OUTCOMES

His left eye pain was immediately relieved, and his decimal vision improved from 0.03 to 0.1 on the day of discharge. Outpatient follow-up 2 weeks later revealed left a decimal vision of 1.2, and a complete resolution of the left eye pain.

LESSONS

Our case indicated that COVID-19 might trigger an autoimmune response that leads to MOG antibody-associated ON, similar to other pathogens that were reported in the past. The treatment response to steroid pulse therapy was preferable following a typical course of MOG antibody-positive ON.