The Immunology of Neuromyelitis Optica-Current Knowledge, Clinical Implications, Controversies and Future Perspectives

BTK and YKL-40 Levels and Their Association with Acute AQP4-IgG-Positive Neuromyelitis Optica Spectrum Disorder

This study investigated the potential correlation between BTK/YKL-40 levels and the severity of AQP4-IgG + NMOSD, aiming to identify biomarkers for disease monitoring and treatment assessment. Plasma YKL-40 expression was measured in 135 AQP4-IgG + NMOSD patients using ELISA. Patients were categorized into pre- and post-IVMP treatment acute phases, as well as during remission, with a healthy control group included. BTK and NF-κB mRNA levels in PBMCs were detected via q-PCR, and BTK/P-BTK protein expression was assessed using Western blotting. Disability was evaluated using the EDSS score, and clinical characteristics were evaluated alongside laboratory tests. Acute-phase NMOSD patients receiving pre-IVMP therapy presented significantly elevated plasma YKL-40 concentrations compared with those of post-treatment patients, patients in remission, and healthy controls. Additionally, these patients presented significantly higher levels of PBMC BTK mRNA, NF-κB mRNA, BTK, and P-BTK protein expression than remission patients and healthy controls. Plasma YKL-40 levels and PBMC BTK/P-BTK protein levels were positively correlated with EDSS scores. The plasma YKL-40 concentration significantly contributes to disease severity and serves as an independent risk factor for acute NMOSD. Elevated BTK, P-BTK, NF-κB, and YKL-40 levels were observed in acute-phase AQP4-IgG + NMOSD patients. These biomarkers are related to disease activity and may predict treatment efficacy. There is a connection among YKL-40, BTK, and P-BTK levels and disease severity, suggesting their potential involvement in the pathogenic mechanism of AQP4-IgG + NMOSD.

Clinical characteristics of overlapping syndrome in patients with GFAP-IgG and MOG-IgG: a case series of 8 patients and literature review

OBJECTIVE

The overlapping syndrome of anti-GFAP and anti-MOG antibodies is extremely rare. This retrospective study reports 8 adult cases of the GFAP-MOG overlapping syndrome.

METHODS

We reviewed the clinical characteristics of 8 adult patients with the GFAP-MOG overlapping syndrome from Jan 2019 and Sep 2023 at the Third Affiliated Hospital, Sun Yat-sen University. Moreover, we searched the literature and included all case reports with this overlapping syndrome since 2018 on PubMed.

RESULTS

The predominant clinical syndrome was meningoencephalomyelitis (5/8), followed by meningoencephalitis (2/8), and myelitis (1/8). Five patients had a flu-like prodromal symptom or diarrhea. No neoplasms were found in these patients. Regarding brain MRI, T2-weighted/fluid-attenuated inversion recovery hyperintensities were in 7 patients and leptomeningeal enhancement was in 4 patients. However, only one patient had periventricular radial linear enhancement. Besides, two patients had large space-occupying lesions. For spinal MRI, T2-hyperintensities were observed in 4 patients, in which 3 patients had longitudinally extensive lesions. All patients were treated with immunotherapy, the median follow-up period was 18 months (range, 3-36 months). Three patients presented relapses during the follow-up, but all cases recovered to mRS scores ≤ 2 at last follow-up. In addition, we also reviewed 14 cases (including 7 adults and 7 children) with this overlapping syndrome by literature review.

CONCLUSION

Our findings provide data to understand the clinical features and prognosis of the GFAP-MOG overlapping syndrome. Recognizing this overlapping syndrome will expand our knowledge, allowing for better management of these patients.

Application of mendelian randomization in ocular diseases: a review

Ocular disorders can significantly lower patients' quality of life and impose an economic burden on families and society. However, for the majority of these diseases, their prevalence and mechanisms are yet unknown, making prevention, management, and therapy challenging. Although connections between exposure factors and diseases can be drawn through observational research, it is challenging to rule out the interference of confounding variables and reverse causation. Mendelian Randomization (MR), a method of research that combines genetics and epidemiology, has its advantage to solve this problem and thus has been extensively utilized in the etiological study of ophthalmic diseases. This paper reviews the implementation of MR in the research of ocular diseases and provides approaches for the investigation of related mechanisms as well as the intervention strategies.

Exploration of the causal associations between circulating inflammatory proteins, immune cells, and neuromyelitis optica spectrum disorder: a bidirectional Mendelian randomization study and mediation analysis

Background

An increasing body of research has demonstrated a robust correlation between circulating inflammatory proteins and neuromyelitis optica spectrum disorders (NMOSD). However, whether this association is causal or whether immune cells act as mediators currently remains unclear.

Methods

We employed bidirectional two-sample Mendelian randomization (TSMR) analysis to examine the potential causal association between circulating inflammatory proteins, immune cells, and NMOSD using data from genome-wide association studies (GWAS). Five different methods for Mendelian randomization analyses were applied, with the inverse variance-weighted (IVW) method being the primary approach. Sensitivity analyses were further performed to assess the presence of horizontal pleiotropy and heterogeneity in the results. Finally, a two-step Mendelian randomization (MR) design was employed to examine the potential mediating effects of immune cells.

Results

A notable causal relationship was observed between three circulating inflammatory proteins (CSF-1, IL-24, and TNFRSF9) and genetically predicted NMOSD. Furthermore, two immune cell phenotypes, genetically predicted CD8 on naive CD8+ T cells, and Hematopoietic Stem Cell Absolute Count were negatively and positively associated with genetically predicted NMOSD, respectively, although they did not appear to function as mediators.

Conclusion

Circulating inflammatory proteins and immune cells are causally associated with NMOSD. Immune cells do not appear to mediate the pathway linking circulating inflammatory proteins to NMOSD.

Altered immune co-inhibitory receptor expression and correlation of LAG-3 expression to disease severity in NMOSD

Co-inhibitory receptors (CIR)s regulate T cell-mediated immune responses and growing evidence links co-inhibitory receptors to the progression of neuroimmunological diseases. We studied the expression levels of CIRs: TIM-3, TIGIT, PD-1 and LAG-3 in the peripheral blood mononuclear cells (PBMCs) of 30 patients with Neuromyelitis optica spectrum disorder (NMOSD), 11 Multiple sclerosis (MS) patients and 31 Healthy controls (HC). We found that the mRNA expression levels of TIM-3 were significantly increased in NMOSD compared with HC, and increased LAG-3 surface protein expression was also observed on T-cells of NMOSD patients. Moreover, we observed a negative correlation between LAG-3 expression and disease severity in NMOSD. Our findings suggest a protective effect of LAG-3 in the setting of NMOSD, and that the differential expression of CIRs observed in this study may play a role in the pathological process of NMOSD.

A Case Report of NMO Transverse Myelitis

BACKGROUND

Transverse myelitis is considered one of the cardinal features of neuromyelitis optica spectrum disorder (NMOSD), an immune-mediated inflammatory condition of the CNS characterized by severe, immune-mediated demyelination and axonal damage predominantly targeting optic nerves and spinal cord. We describe a case in which a diagnosis of NMOSD was established, associated with West Nile Virus (WNV) infection.

CASE PRESENTATION

A healthy 18-year-old female presented with intractable hiccups and rapidly progressing paraparesis. MRI demonstrated T2 edema extending from the medulla to the conus, consistent with longitudinally extensive transverse myelitis. Serum and CSF Aquaporin-4 IgG (AQP4) were both positive with high titers. In conjunction with antiviral therapy, immunomodulatory treatment was initiated using pulse methylprednisolone, plasmapheresis and Rituximab. A month and a half after admission, the patient was fully ambulatory with no residual symptoms. On her rheumatology follow-up visit, West Nile Virus-specific IgM in CSF was found to be positive from the patient's initial presentation.

CONCLUSION

We propose that West Nile Virus may have been the autoimmune trigger to the patient's development of NMOSD, highlighting the importance of evaluating viral triggers in autoimmune diseases.

Frequency of cognitive impairment in patients with neuromyelitis optica spectrum disorder in Mexico

Background

Between 29% and 67% of neuromyelitis optica spectrum disorder patients have cognitive alterations.

Objective

To assess the frequency of cognitive impairment in patients with neuromyelitis optica spectrum disorder in Mexico using the Brief International Cognitive Assessment for Multiple Sclerosis.

Methods

We evaluated 40 neuromyelitis optica spectrum disorder patients and 40 healthy controls from Mexico.

Results

28 (70.0%) patients with neuromyelitis optica spectrum disorder had cognitive impairment in two or more cognitive domains. Student´s T test showed statistically poor performance by neuromyelitis optica spectrum disorder patients compared to healthy controls on all three neuropsychological test scores. This significant difference was observed on the Symbols Digit Modalities Test (t = 8.875; p ≤ 0.001); California Verbal Learning Test-II memory (t = 10.418; p ≤ 0.001); and Brief Visuospatial Memory Test Revised (t = 6.123; p ≤ 0.001).

Conclusions

This study showed that 70% of neuromyelitis optica spectrum disorder patients exhibited cognitive impairment in two or more cognitive domains. Determining the frequency of cognitive impairment will guide the decision of Neuropsychologists in planning cognitive rehabilitation across various domains.

Structural disconnection is associated with disability in the neuromyelitis optica spectrum disorder

OBJECTIVES

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system. Accumulating evidence suggests there is a distinct pattern of brain lesions characteristic of NMOSD, and brain MRI has potential prognostic implications. However, the question of how the brain lesions in NMOSD are associated with its distinct clinical course remains incompletely understood. Here, we aimed to investigate the association between neurological impairment and brain lesions via brain structural disconnection.

METHODS

Twenty patients were diagnosed with NMOSD according to the 2015 International Panel for NMO Diagnosis criteria. The white matter lesions were manually drawn section by section. Whole-brain structural disconnection was estimated, and connectome-based predictive modeling (CPM) was used to estimate the patient's Expanded Disability Status Scale score (EDSS) from their disconnection severity matrix. Furthermore, correlational tractography was performed to assess the fractional anisotropy (FA) and axial diffusivity (AD) of white matter fibers, which negatively correlated with the EDSS score.

RESULTS

CPM successfully predicted the EDSS using the disconnection severity matrix (r = 0.506, p = 0.028; q2 = 0.274). Among the important edges in the prediction process, the majority of edges connected the motor to the frontoparietal network. Correlational tractography identified a decreased FA and AD value according to EDSS scores in periependymal white matter tracts.

DISCUSSION

Structural disconnection-based predictive modeling and local connectome analysis showed that frontoparietal and periependymal white matter disconnection is predictive and associated with the EDSS score of NMOSD patients.

Downregulation of lncRNA XIST may promote Th17 differentiation through KDM6A-TSAd pathway in neuromyelitis optica spectrum disorders

BACKGROUNDS

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease with significant female preponderance. X inactive specific transcript (XIST) is a long non-coding RNA (lncRNA) and a key regulator of X-chromosome inactivation which is related to the sex-bias of autoimmunity. And Th17 cell proportion was significantly elevated in NMOSD according to our previous study.

OBJECTIVES

This study aimed to explore the expression levels of lncRNA XIST-KDM6A-TSAd pathway in lymphocytes of female NMOSD patients, and investigate its possible relationship with pathogenesis of NMOSD.

METHODS AND RESULTS

The study enrolled 30 acute-phase untreated female NMOSD patients and 30 age-matched female healthy controls, their lymphocytes were collected for experiments. Microarray as well as validation experiments showed lncRNA XIST was significantly downregulated in the NMOSD group. And the levels of lysine demethylase 6A (KDM6A) decreased in NMOSD and showed significant positive correlation with XIST. The levels of T cell-specific adapter (TSAd) mRNA and protein levels were significantly lower in NMOSD. And Chromatin immunoprecipitation assay demonstrated that NMOSD had more H3K27me3 modification than control at TSAd promoter region.

CONCLUSIONS

The present study introduced a potential pathway that following lncRNA XIST downregulation, which process may promote Th17 differentiation in NMOSD. These findings shed new light on the immune regulation mechanism about lncRNA XIST and related epigenetic features, which may contribute to develop female-specific treatment plans.

An update on biologic treatments for neuromyelitis optica spectrum disorder

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system mediated by antibodies targeting the aquaporin-4 (AQP4) water channel expressed on astrocytes. The binding of specific antibodies to AQP4 causes complement-dependent cytotoxicity, leading to inflammation and demyelination. Several recent phase 2 and 3 randomized placebo-controlled trials showed the efficacy and safety of monoclonal antibody therapies targeting B-cells, interleukin-6 receptor, and complement.

AREAS COVERED

Current biologic treatments for NMOSD and developments therein, and unresolved issues in NMOSD treatment.

EXPERT OPINION

New biologic treatments demonstrate high efficacy and good safety for patients with AQP4-IgG-positive NMOSD. The optimal therapeutics for seronegative NMOSD, pediatric patients, and female patients who are pregnant or wish to be are unclear, and further research is needed. Also, real-world studies of new biological agents and the data on the durability of their beneficial effects and their long-term safety are required. Effective rescue therapy for an acute attack is critical given permanent disability in NMOSD is attack-related, and biologic agents that treat acute attack are emerging. If such treatments are to become widely applied, studies on the most cost-effective treatment strategies are needed.

Identification of double-stranded DNA in the cerebrospinal fluid of patients with acute neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) characterized by severe myelitis and optic neuritis. Double-stranded DNA (dsDNA) is involved in the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus. However, its role in NMOSD remains unclear. In this study, the concentration of dsDNA in the cerebrospinal fluid (CSF) was quantified in 23 patients with NMOSD and 16 patients with other neurological diseases (ONDs). CSF dsDNA levels in patients with NMOSD (median: 0.03 ng/µL) were significantly higher than those in patients with ONDs (median: 0.01 ng/μl). CSF dsDNA levels showed no significant difference before and after treatment. Elevation of CSF dsDNA levels may suggest its essential role in the augmentation of CNS inflammation in patients with NMOSD.

COVID-19 - a potential trigger for MOGAD-associated optic neuritis: a case report and literature review

SARS-CoV-2 affects the nervous system directly by neurotoxic action, by binding to angiotensin-converting enzyme-2 (ACE2) receptors or indirectly by inducing cytokine storm leading to disruption of the blood-brain barrier, immunological mediation, increasing blood coagulation and as a trigger for autoimmune-mediated demyelinating injuries in the central nervous system. In COVID-19 neuro-ophthalmological manifestations are not so common. Optic neuritis is the result of optic nerve inflammation and has varied causes. In many patients, signs of inflammation are not visible on the fundus, and it usually manifests as papillitis-anterior neuritis, retrobulbar neuritis or visible optic nerve oedema. We are reporting a case of a middle-aged adult diagnosed with myelin oligodendrocyte glycoprotein (MOG) antibody-positive optic neuritis of the right eye post-COVID-19 disease. Routine biochemical and haematological investigations, including electrolytes and hepatic and renal functions, were normal. In cerebrospinal fluid (CSF) - glucose 63.8 mg/dL, protein 39.1 mg/dL and ADA - 1 µ/L. No oligoclonal bands of immunoglobulin G (IgG) were seen on high-resolution electrophoresis. Serum Anti-MOG-antibodies were positive. A gadolinium-contrast magnetic resonance imaging (MRI) of the brain and orbits shows post-contrast enhancement in the superior aspect of the right intraconal soft tissue. The right optic nerve appears bulky and heterogeneous with peripheral post-contrast enhancement along its entire length suggestive of neuritis. A diagnosis of MOG antibody-positive optic neuritis was made, and the patient was treated with an injection of Methylprednisolone with intravenous immunoglobulin. Each day, the evaluation of the right eye showed remarkable improvement from finger counting to 6/6 vision. The patient was discharged on the 9th day of admission. We can conclude that early diagnosis was essential for improving the long-term outcome of the patient.

Optic neuromyelitis after vaccination against SARS-CoV-2

Neuromyelitis optica is an autoimmune demyelinating astrocytopathy of the central nervous system that primarily affects the optic nerve and spinal cord. It is considered a multifactorial disease associated with antibodies against aquaporin 4, with complement cascade activation and lymphocytic infiltration leading to axonal loss and causing significant morbidity and disability. In addition, cases of inflammatory diseases of the central nervous system have been described after vaccination against SARS-CoV-2, mainly acute disseminated encephalomyelitis. Also, a few cases of neuromyelitis optica spectrum disorder, mostly aquaporin 4+, have been reported. We describe a patient who developed symptoms suggestive of acute disseminated encephalomyelitis the next day after vaccination against SARS-CoV-2. Three months later, a longitudinally extensive transverse myelitis compatible with aquaporin 4+ neuromyelitis optica was successfully treated with an interleukin 6 inhibitor. There is no proven association and research is needed to establish whether optic neuromyelitis is related to vaccination; this is a single case report from which no conclusion can be drawn.

Risk factors associated with permanent disability in neuromyelitis optica spectrum disorders

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system. In NMOSD, a relapse results in increased disability.

OBJECTIVE

To assess risk factors associated with permanent disability (PD) in patients with neuromyelitis optica spectrum disorders (NMOSD).

METHODS

We evaluated 34 cases (who developed permanent disability) and 33 controls. The assessment included the following variables: sociodemographic data and characteristics of the disease. Logistic regression analysis was performed to adjust variables associated with PD.

RESULTS

fifty-one percent developed PD during follow-up; 15 (22%) developed permanent visual disability, 13 (19%) developed permanent motor disability and 6 (9%) were restricted to wheelchair. Factors associated with PD in the crude analysis were: age at onset ≥ 50 years (OR 3.95, 95% IC 1.12-13.94, p= 0.032), time from onset to diagnosis ≥ 12 months (OR 3.30, 95% IC 1.13-9.64, p= 0.029), time from onset to treatment ≥ 60 months (OR 4.16, 95% IC 1.03-16.85, p= 0.045), EDSS ≥ 4.0 at the first appointment (OR 3.21, 95% IC 1.18-8.76, p= 0.022) and severe relapses during disease evolution (OR 5.72, 95% IC 1.98-16.57, p= 0.001). Factors associated with PD in the adjusted analysis were: age at onset ≥ 50 years (OR 5.82, 95% IC 1.30-26.05, p= 0.021), time from onset to diagnosis ≥ 12 months (OR 5.43, 95% IC 1.47-20.08, p= 0.011) and severe relapses during disease evolution (OR 6.65, 95% IC 1.98-22.31, p= 0.002).

CONCLUSION

Half of patients with NMOSD may develop PD during disease evolution. Age of onset ≥ 50 years, delay to diagnosis ≥12 months and initial EDSS ≥ 4.0 constitute the strongest risk factors for PD.

General anesthesia, using remimazolam, for the patient with myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD): A case report

RATIONALE

Myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is one of auto-immune demyelinating diseases of nervous system. Although both regional anesthesia and general anesthesia has been successfully performed in the patient with demyelinating diseases of nervous system, it has been controversial which one is better.

PATIENT CONCERNS

Forty-four male patient was admitted for arthroscopic elbow surgery due to limitation of range of motion. The patient was diagnosed as MOGAD with anti-N-methyl-D-aspartate (NMDA) receptor encephalitis, and steroid was used to prevent and treat symptoms and signs.

DIAGNOSIS

He was diagnosed as MOGAD with anti-NMDA receptor encephalitis, 1 year ago. The patient complaint of dizziness, diplopia, nausea, vomiting, seizure, general weakness and so on when he was confirmed as MOGAD with anti-NMDA receptor encephalitis. The diagnosis of MOGAD was confirmed with positive anti-myelin oligodendrocyte glycoprotein (MOG) Immunoglobulin (Ig)G and negative anti-aquaporin 4 (AQP4) IgG in the blood.

INTERVENTIONS AND OUTCOMES

After steroid cover, total intravenous anesthesia (TIVA) with remimazolam and remifentanil was established for the patients. Rocuronium was administered under monitoring of neuromuscular blockade, using train of 4 (TOF). The operation was performed without any event under right lateral decubitus position. The patient was uneventfully recovered from anesthesia.

LESSONS

The case report showed total intravenous anesthesia with remimazolam and remifentanil under proper monitoring was successfully performed in the patient with MOGAD.

Correlation between ERα gene polymorphism and multiple sclerosis and neuromyelitis optica

OBJECTIVE

To study the polymorphism distribution of estrogen receptor (ER) α gene and the correlation between different types of polymorphism in multiple sclerosis (MS) and neuromyelitis optica (NMO) patients.

METHODS

Forty-six cases of MS and NMO diagnosed from June 2018 to December 2019 were collected. Peripheral venous blood samples were collected. The patient's gender, age of onset, course of disease, and other clinical data were recorded. Fifty-eight healthy volunteers of the same age and sex were selected. By means of Pvu II and Xba I restriction fragment length polymorphism enzyme recognition sites of ER α gene, polymerase chain reaction-restriction fragment length polymorphism analysis was conducted.

RESULTS

There was no significant difference in the frequency distribution of ER α gene's PP, Pp, and pp genotype between MS and NMO case group and control group (P = .598). Frequency distribution of ER α gene's XX, Xx, and xx was statistically significant between MS and NMO case group and control group (P = .021). Among them, distribution of Xx and Xx gene frequency between patient group and the control group was statistically significant (P = .001, OR = 4.622, 95% CI: 1.803-11.852). There was no significant correlation between ER α genotypes and the onset age in patient group (P > .05). The difference was statistically significant in disease duration of XX and Xx genotype (P = .006). The comparison of Xx and xx genotype frequency distribution in gender exists a difference(P = .047, OR = 7.500, 95% CI: 1.023-54.996).

CONCLUSIONS

Xba I gene polymorphisms in the ER α gene have correlation with MS and NMO. Xba I gene could be a risk factor of MS and NMO pathogenesis, especially the women with Xx genotype are more vulnerable. Xba I gene polymorphisms in the ER α gene may impact the disease duration of MS and NMO, or rather, the disease duration of Xx genotype persists longer than Xx genotype. Pvu II gene polymorphisms in the ER α gene has no correlation with MS and NMO.

Neuromyelitis optica spectrum disorder with negative aquaporin-4 antibodies and positive anti-myelin oligodendrocyte glycoprotein antibodies: A case report

Neuromyelitis optica spectrum disorders (NMOSDs) are rare autoimmune-mediated chronic inflammatory disorders involving the central nervous system. The concept of NMOSDs has widened up recently. Its diagnostic criteria have broadened the knowledge of this particular disease including the atypical cases where antiaquaporin-4 antibody is negative and anti-myelin oligodendrocyte glycoprotein (MOG) antibody is positive. Myelin oligodendrocyte glycoprotein is a protein expressed on the outer surface of myelin sheath and oligodendrocytes of the central nervous system. The detection of anti-MOG-Ab is emerging evidence, and thus, research on the role of this antibody in such seronegative cases is still underway. Early diagnosis and adequate therapy is essential in such cases. Here, we report an eight-year-old girl who was diagnosed with NMOSDs and found to have anti-MOG antibodies in place of AQP-4 antibodies.

NMOSD-Diagnostic Dilemmas Leading towards Final Diagnosis

(1) Background: The emergence of white matter lesions in the central nervous system (CNS) can lead to diagnostic dilemmas. They are a common radiological symptom and their patterns may overlap CNS or systemic diseases and provoke underdiagnosis or misdiagnosis. The aim of the study was to assess factors influencing the underdiagnosis of neuromyelitis optica spectrum disorder (NMOSD) as well as to estimate NMOSD epidemiology in Lubelskie voivodeship, Poland. (2) Methods: This retrospective study included 1112 patients, who were made a tentative or an established diagnosis of acute or subacute onset of neurological deficits. The evaluation was based on medical history, neurological examination, laboratory and radiographic results and fulfilment of diagnosis criteria. (3) Results: Up to 1.62 percent of patients diagnosed with white matter lesions and up to 2.2% of the patients previously diagnosed with MS may suffer from NMOSD. The duration of delayed diagnosis is longer for males, despite the earlier age of onset. Seropositive cases for antibodies against aquaporin-4 have worse prognosis for degree of disability. (4) Conclusions: Underdiagnosis or misdiagnosis in NMOSD still remains a problem in clinical practice and has important implications for patients. The incorrect diagnosis is caused by atypical presentation or NMOSD-mimics; however, covariates such as gender, onset and diagnosis age may also have an influence.

Sera of Neuromyelitis Optica Patients Increase BID-Mediated Apoptosis in Astrocytes

Neuromyelitis optica (NMO) is a rare disease usually presenting with bilateral or unilateral optic neuritis with simultaneous or sequential transverse myelitis. Autoantibodies directed against aquaporin-4 (AQP4-IgG) are found in most patients. They are believed to cross the blood−brain barrier, target astrocytes, activate complement, and eventually lead to astrocyte destruction, demyelination, and axonal damage. However, it is still not clear what the primary pathological event is. We hypothesize that the interaction of AQP4-IgG and astrocytes leads to DNA damage and apoptosis. We studied the effect of sera from seropositive NMO patients and healthy controls (HCs) on astrocytes’ immune gene expression and viability. We found that sera from seropositive NMO patients led to higher expression of apoptosis-related genes, including BH3-interacting domain death agonist (BID), which is the most significant differentiating gene (p < 0.0001), and triggered more apoptosis in astrocytes compared to sera from HCs. Furthermore, NMO sera increased DNA damage and led to a higher expression of immunological genes that interact with BID (TLR4 and NOD-1). Our findings suggest that sera of seropositive NMO patients might cause astrocytic DNA damage and apoptosis. It may be one of the mechanisms implicated in the primary pathological event in NMO and provide new avenues for therapeutic intervention.

Optic neuritis: A South African hospital-based prospective study protocol

Background

Optic neuritis is a relatively common disease with an estimated lifetime risk of 0.6 per 1000; the estimated prevalence is 1–5 per 100 000/year. It occurs because of inflammation of the optic nerve from a variety of causes. The diagnosis of the disorder is established clinically and current literature is predominantly based on white patients from high-income countries. Optic neuritis presents differently in black patients compared to white patients. This study aims to assess the presentation and outcome of optic neuritis patients in a South African setting.

Methods

This is a prospective, hospital-based cohort study that will enrol patients with optic neuritis presenting to either the neurology department at Chris Hani Baragwanath Academic Hospital or the ophthalmology department at St John Eye Hospital, both in Johannesburg, South Africa. The specific aetiologies, clinical presentation and radiological findings will be studied, and the patient’s course over one year will be documented in three-monthly follow-up visits. A specific group of patients with Neuromyelitis Optica Spectrum Disorders (NMOSD) and Myelin Oligodendrocyte Glycoprotein Associated Disorders (MOGAD) optic neuritis will be followed up for 5 years at yearly intervals.

Discussion

This study represents one of the few cohort studies in Sub-Saharan Africa that seeks to investigate optic neuritis. Our hope is that it will lead to better insights regarding the presentation, course and outcome of this condition. We will also analyse the data with a view of developing a predictive model for good visual outcome.

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.

Magnetic Resonance Imaging of Autoimmune Demyelinating Diseases as a Diagnostic Challenge for Radiologists: Report of Two Cases and Literature Review

The magnetic resonance characteristics of autoimmune demyelinating diseases are complex and represent a challenge for the radiologist. In this study we presented two different cases of detected autoimmune demyelinating diseases: one case of acute disseminated encephalomyelitis and one case of neuromyelitis optica, respectively. Expected and unexpected findings of magnetic resonance imaging examination for autoimmune demyelinating diseases were reported in order to provide a valuable approach for diagnosis. In particular, we highlight, review and discuss the presence of several uncommon imaging findings which could lead to a misinterpretation. The integration of magnetic resonance imaging findings with clinical and laboratory data is necessary to provide a valuable diagnosis.

Pathways Involved in Remyelination after Cerebral Ischemia

Brain ischemia, also known as ischemic stroke, occurs when there is a lack of blood supply into the brain. When an ischemic insult appears, both neurons and glial cells can react in several ways that will determine the severity and prognosis. This high heterogeneity of responses has been a major obstacle in developing effective treatments or preventive methods for stroke. Although white matter pathophysiology has not been deeply assessed in stroke, its remodelling can greatly influence the clinical outcome and the disability degree. Oligodendrocytes, the unique cell type implied in CNS myelination, are sensible to ischemic damage. Loss of myelin sheaths can compromise axon survival, so new Oligodendrocyte Precursor Cells are required to restore brain function. Stroke can, therefore, enhance oligodendrogenesis to regenerate those new oligodendrocytes that will ensheath the damaged axons. Given that myelination is a highly complex process that requires coordination of multiple pathways such as Sonic Hedgehog, RTKs or Wnt/β-catenin, we will analyse new research highlighting their importance after brain ischemia. In addition, oligodendrocytes are not isolated cells inside the brain, but rather form part of a dynamic environment of interactions between neurons and glial cells. For this reason, we will put some context into how microglia and astrocytes react against stroke and influence oligodendrogenesis to highlight the relevance of remyelination in the ischemic brain. This will help to guide future studies to develop treatments focused on potentiating the ability of the brain to repair the damage.

An Update on the Laboratory Diagnosis of Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder of the central nervous system that is specifically associated with demyelination of spinal cord and optic nerves. The discovery of specific autoantibody markers such as aquaporin-4 IgG and myelin oligodendrocyte glycoprotein IgG has led to several methodologies being developed and validated. There have been numerous investigations of the clinical and radiological presentations used in the clinical diagnosis of NMOSD. However, although various laboratory diagnostic techniques have been standardized and validated, a gold-standard test has yet to be finalized due to uncertain sensitivities and specificities of the methodologies. For this review, the literature was surveyed to compile the standardized laboratory techniques utilized for the differential diagnosis of NMOSD. Enzyme-linked immunosorbent assays enable screening of NMOSD, but they are considered less sensitive than cell-based assays (CBAs), which were found to be highly sensitive and specific. However, CBAs are laborious and prone to batch variations in their results, since the expression levels of protein need to be maintained and monitored meticulously. Standardizing point-of-care devices and peptide-based assays would make it possible to improve the turnaround time and accessibility of the test, especially in resource-poor settings.

R-Ras1 and R-Ras2 Expression in Anatomical Regions and Cell Types of the Central Nervous System

Since the optic nerve is one of the most myelinated tracts in the central nervous system (CNS), many myelin diseases affect the visual system. In this sense, our laboratory has recently reported that the GTPases R-Ras1 and R-Ras2 are essential for oligodendrocyte survival and maturation. Hypomyelination produced by the absence of one or both proteins triggers axonal degeneration and loss of visual and motor function. However, little is known about R-Ras specificity and other possible roles that they could play in the CNS. In this work, we describe how a lack of R-Ras1 and/or R-Ras2 could not be compensated by increased expression of the closely related R-Ras3 or classical Ras. We further studied R-Ras1 and R-Ras2 expression within different CNS anatomical regions, finding that both were more abundant in less-myelinated regions, suggesting their expression in non-oligodendroglial cells. Finally, using confocal immunostaining colocalization, we report for the first time that R-Ras2 is specifically expressed in neurons. Neither microglia nor astrocytes expressed R-Ras1 or R-Ras2. These results open a new avenue for the study of neuronal R-Ras2's contribution to the process of myelination.

Inebilizumab for treatment of neuromyelitis optica spectrum disorder in patients with prior rituximab use from the N-MOmentum Study

BACKGROUND

The B-cell-depleting agent rituximab (anti-CD20) was historically used to prevent attacks in neuromyelitis optica spectrum disorder (NMOSD). Inebilizumab, which targets and depletes CD19-expressing B cells, plasmablasts, and some plasma cells, received approval from the US Food and Drug Administration for treatment of NMOSD based on results from the randomized, placebo-controlled, phase 2/3 N-MOmentum trial. Because of their closely related mechanisms of action, consideration as to whether inebilizumab may be a suitable treatment option for patients with prior rituximab experience is important. This post hoc analysis of data from N-MOmentum assessed inebilizumab efficacy and tolerability in participants previously treated with rituximab.

METHODS

Adjudicated attacks, secondary efficacy outcomes, and treatment-emergent adverse events were assessed by prior rituximab use during a 6-month randomized control period and open-label period.

RESULTS

Seventeen participants in N-MOmentum had prior rituximab use, of whom 13 were randomly assigned to the inebilizumab treatment group. Seven of these participants had breakthrough attacks prior to enrollment (annualized attack rate, 0.78 attacks/person-year) despite rituximab use. While they were receiving inebilizumab in the randomized control period, 1 of 13 participants with prior rituximab use had an attack (hazard ratio vs all placebo, 0.16; 95% confidence interval: 0.02 1.20; p = 0.07). Two additional participants with prior rituximab use experienced attacks on inebilizumab during the open-label period, with an overall annualized attack rate of 0.08 (95% confidence interval: 0.02 0.34) attacks/person-year. This annualized attack rate was similar to that of participants without prior rituximab use (0.10 [95% confidence interval: 0.07 0.15]). None of the 7 participants who experienced attacks while taking rituximab experienced an attack while receiving inebilizumab. Two (12%) participants with prior rituximab use experienced serious treatment-emergent adverse events related to inebilizumab, with serious or grade ≥3 infections occurring in 3 (18%) participants each. No deaths or opportunistic infections were reported in this cohort.

CONCLUSIONS

These findings support the efficacy of inebilizumab in participants with NMOSD who had previously been treated with rituximab. Infections occurred in nearly all study participants with prior rituximab exposure, highlighting a need for clinical vigilance in such individuals. Further studies are necessary to determine potential safety concerns of inebilizumab, including risk of infection, in rituximab-experienced patients. ClinicalTrials.gov identifier: NCT02200770.

Pediatric Neuromyelitis Optica Spectrum Disorder: Case Series and Literature Review

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a central nervous system (CNS) inflammatory demyelinating disease characterized by recurrent inflammatory events that primarily involve optic nerves and the spinal cord, but also affect other regions of the CNS, including hypothalamus, area postrema and periaqueductal gray matter. The aquaporin-4 antibody (AQP4-IgG) is specific for NMOSD. Recently, myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) have been found in a group of AQP4-IgG negative patients. NMOSD is rare among children and adolescents, but early diagnosis is important to start adequate therapy. In this report, we present cases of seven pediatric patients with NMOSD and we review the clinical and neuroimaging characteristics, diagnosis, and treatment of NMOSD in children.

Sparser macula microvasculature in neuromyelitis optica spectrum disorder occurs independently of optic neuritis

PURPOSE

To evaluate the macula microvascular perfusion in neuromyelitis optica spectrum disorder (NMOSD) patients and assess the correlation with their clinical features.

METHODS

35 aquaporin-4 seropositive NMOSD patients (38 NMOSD eyes without optic neuritis, NMOSD-NON, and 32 NMOSD eyes with optic neuritis) and 35 healthy controls (HC) were included in our study. Swept-source optical coherence tomography angiography (SS-OCTA) was used to image and segment the macula microvasculature into the inner macula vascular complex (IVC), superficial vascular plexus (SVC), and deep vascular plexus (DVC). An inbuilt software within the OCTA tool was used to measure the microvascular perfusion in these two plexuses.

RESULTS

NMOSD eyes without optic neuritis showed sparser (P < 0.05) IVC and SVC compared with healthy controls; NMOSD eyes with optic neuritis showed significantly sparser (P < 0.001) IVC, SVC, and DVC when compared with healthy controls respectively. NMOSD eyes with optic neuritis showed significantly sparser IVC (P = 0.002), SVC (P = 0.001) and DVC (P = = 0.040) when compared with eyes without optic neuritis.

CONCLUSIONS

Microvascular impairment in NMOSD patients occurs independently of ON. Microvascular impairment is associated with reduced visual acuity and frequency of ON.

Physical, Emotional, Medical, and Socioeconomic Status of Patients With NMOSD: A Cross-Sectional Survey of 123 Cases From a Single Center in North China

Objective: This study aimed to assess the physical, emotional, medical, and socioeconomic conditions of patients with neuromyelitis optica spectrum disorder (NMOSD) in North China.

Methods: A cross-sectional survey of patients with NMOSD was performed, based on an established questionnaire from the Multiple Sclerosis Patient Survival Report 2018. Logistic regression analysis was conducted to define the significant determinants of certain physical or emotional characteristics of patients. A total of 123 patients were included.

Results: A total of 63.4% of participants were initially diagnosed with conditions other than NMOSD, with a median delay of 6 months for accurate diagnosis. An aggregate of 72.2% of patients had one or more relapses, corresponding to an annual relapse rate of 0.8. Paresthesia was the most frequent physical symptom among patients both at disease onset (53.7%) and throughout the duration of the disease (86.2%). Onset in elderly (>50 years) patients was associated with an annual Expanded Disability Status Scale increase ≥1, compared with onset in younger (<30 years) patients (P = 0.001, OR = 7.83). A total of 76.4% of patients had received attack-prevention treatments in the remission phase, and 31.7 and 10.6% of patients had ever been administered rituximab and traditional Chinese medicine, respectively. Additionally, 63.4 and 43.1% of patients reported participating in few or no social activities and being out of work because of the disease. To be noted, 76.4% of patients reported suffering from negative emotions, with the most frequent being worry (60.2%), with 20.3% of patients experiencing suicidal thoughts. The inability to work and participating in few or no social activities due to NMOSD were two determinants of experiencing negative emotions (P_work = 0.03, OR_work = 3.34; P_{socialactivities} = 0.02, OR_{socialactivities} = 3.19).

Conclusion: This study reported patient perspectives on NMOSD in North China, whereby demonstrating that the inability to work and participating in few or no social activities due to NMOSD rather than the physical impairment caused by the disease, was directly associated with patients experiencing negative emotions. This insight offers potential ways to manage patients' negative emotions by enhancing family and social support and facilitating active employment.

Overlapping syndrome mimicking infectious meningoencephalitis in a patient with MOG and GFAP IgG

Background

Central nervous system overlapping autoimmune syndromes are uncommon, especially with the coexistence of MOG-IgG and GFAP-IgG.

Case presentation

A 23-year-old woman presented with transient convulsions, a loss of consciousness, persistent fever, headache, and vomiting. Cerebrospinal fluid (CSF) analysis revealed elevated cellularity, and magnetic resonance imaging (MRI) showed diffuse leptomeningeal enhancement. She had fever and headache with antiviral and antibiotic treatment for 2 weeks, and she had empirical anti-tuberculosis treatment and oral prednisolone therapy. She was followed for 3 months after presentation with improved symptoms and normal CSF analysis. A 3-month follow-up MRI showed asymmetric lesions in the cerebellum, corona radiata, and white matter with enhancement. The anti-tuberculosis treatment was continued, and steroid therapy was discontinued. After she stopped taking prednisolone, an interrupted headache gradually appeared. MRI at 4 months after presentation revealed a partial reduction in lesions but enlarged areas in the left cerebellum and right parietal white matter and a new lesion in the region of the right ependyma with linear enhancement. Her CSF was positive for anti-myelin oligodendrocyte glycoprotein (MOG) and anti-glial fibrillary acidic protein (GFAP) antibodies using a transfected cell-based assay. She was diagnosed with overlapping syndrome of MOG‑IgG‑associated disease and GFAP astrocytopathy. She received steroid pulse therapy (methylprednisolone, 1 g for 5 days), followed by a gradual tapering of oral prednisolone and the addition of an immunosuppressant (tacrolimus, 3 mg per day). Six months after the initial presentation, she had no symptoms. An MRI showed that the lesions had diminished, and no enhancement was found.

Conclusions

We report a case that was positive for double antibodies, which was initially misdiagnosed as infectious meningoencephalitis. This case broadens the clinical and phenotypic presentation of the overlapping syndrome spectrum.

Inebilizumab for treatment of neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease characterized by recurrent optic neuritis and transverse myelitis often resulting in severe disability. Anti-AQP4-immunoglobulin G (IgG) is a pathogenic product of CD19-positive plasma cells found in most, but not all, individuals with NMOSD and is associated with immune-mediated neurologic injury. Inebilizumab, an afucosylated humanized IgG1κ, anti-CD19 monoclonal antibody, may target pathogenic CD19-expressing B cells. In a Phase II/III trial, inebilizumab significantly reduced the proportion of participants experiencing an NMOSD attack and was well tolerated versus placebo. Fewer treated participants had worsening disability than those receiving placebo. Inebilizumab was approved in 2020 by the US FDA for treatment of anti-AQP4 antibody positive NMOSD.

Th17-Related Cytokines as Potential Discriminatory Markers between Neuromyelitis Optica (Devic's Disease) and Multiple Sclerosis-A Review

Multiple sclerosis (MS) and Devic’s disease (NMO; neuromyelitis optica) are autoimmune, inflammatory diseases of the central nervous system (CNS), the etiology of which remains unclear. It is a serious limitation in the treatment of these diseases. The resemblance of the clinical pictures of these two conditions generates a partial possibility of introducing similar treatment, but on the other hand, a high risk of misdiagnosis. Therefore, a better understanding and comparative characterization of the immunopathogenic mechanisms of each of these diseases are essential to improve their discriminatory diagnosis and more effective treatment. In this review, special attention is given to Th17 cells and Th17-related cytokines in the context of their potential usefulness as discriminatory markers for MS and NMO. The discussed results emphasize the role of Th17 immune response in both MS and NMO pathogenesis, which, however, cannot be considered without taking into account the broader perspective of immune response mechanisms.

Cell-based therapy for ocular disorders: A promising frontier

As the ocular disorders causing long-term blindness or optical abnormalities of the ocular tissue affect the quality of life of patients to a large extent, awareness of their corresponding pathogenesis and the earlier detection and treatment need more consideration. Though current therapeutics result in desirable outcomes, they do not offer an inclusive solution for development of visual impairment to blindness. Accordingly, stem cells, because of their particular competencies, have gained extensive attention for application in regenerative medicine of ocular diseases. In the last decades, a wide spectrum of stem cells surrounding mesenchymal stem/stromal cells (MSC), neural stem cells (NSCs), and embryonic/induced pluripotent stem cells (ESCs/iPSCs) accompanied by Müller glia, ciliary epithelia-derived stem cells, and retinal pigment epithelial (RPE) stem cells have been widely investigated to report their safety and efficacy in preclinical models and also human subjects. In this regard, in the first interventions, RPE cell suspensions were successfully utilized to ameliorate visual defects of the patients suffering from age-related macular degeneration (AMD) after subretinal transplantation. Herein, we will explain the pathogenesis of ocular diseases and highlight the novel discoveries and recent findings in the context of stem cell-based therapies in these disorders, focusing on the in vivo reports published during the last decade.

Macular vessel density differs in multiple sclerosis and neuromyelitis optica spectrum disorder: An optical coherence tomography angiography study

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are inflammatory and demyelinating diseases that commonly manifest with optic neuritis (ON) but differ in the pathogenic mechanism. Although it was shown that retinal vessels might alter in MS and NMOSD, a comparative study has not been reported. This study evaluated the macular vessel density in 40 MS patients, 13 NMOSD patients, and 20 controls using optical coherence tomography angiography. The vessel density of superficial capillary plexus (SCP) was significantly lower in ON eyes (MS+ON, NMOSD+ON) than in non-ON eyes (MS-ON, NMOSD-ON) and controls. The density of deep capillary plexus (DCP) was significantly increased in MS+ON and MS-ON eyes compared to healthy eyes. In NMOSD+ON and NMOSD-ON, the DCP did not remarkably differ from the control group. A significant positive correlation was noted between SCP and ganglion cell complex (GCC) thickness in MS+ON, MS-ON, and NMOSD+ON. The DCP did not significantly correlate with GCC thickness, but it increased or decreased with ganglion cell loss in MS and NMOSD, respectively. In conclusion, our findings suggest that the capillary changes in MS patients are secondary to ganglion cells' atrophy, while vasculopathy seems to be a primary process in NMOSD patients.

Structural and Functional Alterations in Visual Pathway After Optic Neuritis in MOG Antibody Disease: A Comparative Study With AQP4 Seropositive NMOSD

Background: Optic neuritis (ON) is an important clinical manifestation of neuromyelitis optic spectrum disease (NMOSD). Myelin oligodendrocyte glycoprotein (MOG) antibody-related and aquaporin 4 (AQP4) antibody-related ON show different disease patterns. The aim of this study was to explore the differences in structure and function of the visual pathway in patients with ON associated with MOG and AQP4 antibodies.

Methods: In this prospective study, we recruited 52 subjects at Beijing Tiantan Hospital, including 11 with MOG Ig+ ON (MOG-ON), 13 with AQP4 Ig+ ON (AQP4-ON), and 28 healthy controls (HCs). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of optic radiation (OR), primary visual cortex volume (V1), brain volume, and visual acuity (VA) were compared among groups. A multiple linear regression was used to explore associations between VA and predicted factors. In addition, we used optical coherence tomography (OCT) to examine thickness of the peripapillary retinal nerve fiber layer (pRNFL) and retinal ganglion cell complex (GCC) in a separate cohort consisting of 15 patients with ON (8 MOG-ON and 7 AQP4-ON) and 28 HCs.

Results: Diffusion tensor imaging showed that the FA of OR was lower than controls in patients with AQP4-ON (p = 0.001) but not those with MOG-ON (p = 0.329) and was significantly different between the latter two groups (p = 0.005), while V1 was similar in patients with MOG-ON and AQP4-ON (p = 0.122), but was lower than controls in AQP4-ON (p = 0.002) but not those with MOG-ON (p = 0.210). The VA outcomes were better in MOG-ON than AQP4-ON, and linear regression analysis revealed that VA in MOG-ON and AQP4-ON was both predicted by the FA of OR (standard β = −0.467 and −0.521, p = 0.036 and 0.034). Both patients of MOG-ON and AQP4-ON showed neuroaxonal damage in the form of pRNFL and GCC thinning but showed no statistically significant difference (p = 0.556, 0.817).

Conclusion: The structural integrity of OR in patients with MOG-ON, which is different from the imaging manifestations of AQP4-ON, may be a reason for the better visual outcomes of patients with MOG-ON.

Differentiation between multiple sclerosis and neuromyelitis optica spectrum disorder using optical coherence tomography angiography

Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are autoimmune demyelinating diseases of distinct etiology presenting with optic neuritis (ON). This study aimed to identify the macular and peripapillary neurovascular alterations that may facilitate the differentiation between NMOSD and MS eyes using spectral-domain optical coherence tomography (OCT) and OCT angiography (OCTA). A total of 13 NMOSD patients and 40 MS patients were evaluated. After ON, the radial peripapillary capillary (RPC) vessel density was significantly decreased in the superior (S) and inferior (I) sectors in NMOSD compared with MS eyes, whereas in non-ON eyes, the temporal (T) sector of RPC was reduced in MS group. In the ON eyes, the retinal nerve fiber layer in the I and T quadrants was thinner in NMOSD than in MS. Regarding ON and non-ON eyes, the macular capillary plexuses, and the ganglion cell complex thickness did not differ between NMOSD and MS. The ratios, based on the disease-specific intra-eye RPC vessel density reduction pattern, were the best discriminants between NMOSD and MS, i.e., inferior to nasal (I/N) and I/T ratios for ON eyes, and S/T and N/T ratios for non-ON eyes. Our results show that the OCTA-based simple ratios may be useful in distinguishing NMOSD and MS patients.

FTY720 Exacerbates Blood-Brain Barrier Dysfunction Induced by IgG Derived from Patients with NMO and MOG Disease

Neuromyelitis optica (NMO) and myelin oligodendrocyte glycoprotein (MOG) antibody-related disease (MOG disease) are inflammatory demyelinating diseases of the central nervous system (CNS). The disruption of the blood-brain barrier (BBB) is considered a key step in the pathogenesis of NMO and MOG disease. Although a previous report indicated that circulating immunoglobulin G (IgG) from NMO patients disrupts the BBB, the effect of IgG from patients with MOG disease has not been elucidated. In addition, it has been reported that some disease-modifying drugs for multiple sclerosis are harmful to NMO by an unknown mechanism. This study aimed to examine the effects of IgG from patients with NMO or MOG disease on BBB integrity. We also examined the effects of disease-modifying drugs (fingolimod [FTY720] and dimethyl fumarate [DMF]) on IgG-treated brain capillary endothelial cells. We used in vitro BBB models constructed with rat brain capillary endothelial cells (RBECs) to examine the effects on BBB function. The integrity of the RBECs was assessed by measuring transendothelial resistance (TEER) and cell viability. NMO or MOG-IgG treatment decreased TEER and cell viability in the endothelial monolayer model. Although FTY720 and DMF did not affect barrier function or cell viability under normal conditions, disease IgG-induced barrier dysfunctions were worsened by the presence of FTY720. These data indicate that circulating IgG in patients with NMO or MOG disease worsens BBB function. Furthermore, in patients with NMO or MOG disease treated with FTY720, changes in the integrity of the BBB were found to exacerbate the disease.

The prevalence of anti-neurofascin-155 antibodies in patients with neuromyelitis optica spectrum disorders

Anti-neurofascin-155 (NF155) antibodies have been observed in two cases with neuromyelitis optica spectrum disorders (NMOSD). This study investigated the prevalence of anti-NF155 antibodies in patients with NMOSD and the clinical features of anti-NF155 antibody-positive patients. Sera from 129 patients with NMOSD were screened with anti-NF155 antibodies by cell-based assay (CBA) and re-examined using immunostaining of teased mouse sciatic nerve fibres. Fifty-six patients with multiple sclerosis (MS) and 50 healthy controls (HC) were also enrolled for detecting anti-NF155 antibodies. A total of 12.40% (16 of 129) of patients with NMOSD were positive for anti-NF155 antibodies confirmed by both CBA and immunostaining. Immunoglobulin (Ig) G1 was the predominant subclass. However, none of 56 MS patients or 50 HC were positive for anti-NF155 antibodies. Anti-NF155 antibody-positive NMOSD patients had a higher proportion of co-existing with autoimmune diseases (p < 0.001) and higher positive rates of serum non-organ-specific autoantibodies, including anti-SSA antibodies (p < 0.001), anti-SSB antibodies (p = 0.008), anti-Ro-52 antibodies (p < 0.001) and rheumatoid factor (p < 0.001). Five anti-NF155 antibody-positive NMOSD patients who took part in the nerve conduction study showed mildly abnormal results. Differences in some nerve conduction study parameters were observed between anti-NF155 antibody-positive and negative patients. Anti-NF155 antibodies occurred in a small proportion of NMOSD patients. Anti-NF155 antibody-positive NMOSD patients tended to co-exist with autoimmune diseases.

Eculizumab in the Treatment of Aquaporin-4 Seronegative Neuromyelitis Optica Spectrum Disorder: A Case Report

Objective: To report the case of a 35-year-old woman with treatment-resistant aquaporin-4 (AQP-4) immunoglobulin G (IgG) seronegative neuromyelitis optica spectrum disorder (NMOSD) successfully treated with eculizumab (a terminal complement inhibitor).

Methods: The investigational procedures and treatment regimens the patient received were documented over 8 years [2012 (first presentation) to 2020].

Results: The patient presented with subacute onset of lower-limb weakness and numbness, gait imbalance, and urinary incontinence. Magnetic resonance imaging (MRI) showed abnormalities in the thoracic spine from T7 to T10, but brain and cervical spine scans, visual evoked potential latencies, and IgG index were normal; cerebrospinal fluid pleocytosis and oligoclonal bands were both present. After treatment with intravenous methylprednisolone 1 g/day for 5 days, the patient was discharged without medication to acute rehabilitation but experienced relapses from 2012 to 2014. She was treated with oral prednisone (initiated at 40 mg/day in 2014; the dose was halved in 2015 due to weight gain) and mycophenolate mofetil (MMF) 1 g twice daily (from June 2015), but between 2014 and 2019 experienced 4–5 relapses/year, requiring treatment with intravenous methylprednisolone, with added maintenance plasma exchange from 2018 onwards. Although the patient tested negative for antibodies to AQP-4 and myelin oligodendrocyte glycoprotein, she was diagnosed with NMOSD in February 2017, based on recurrent episodes of longitudinal extensive transverse myelitis, MRI changes, and area postrema syndrome. By 2018 the patient needed a cane to walk. Prednisone and MMF were discontinued mid-2018, and rituximab was prescribed from July 2018 (maintenance regimen two 1 g doses 2 weeks apart every 6 months) but discontinued in July 2019 owing to lack of significant improvement. From July 2019 eculizumab was prescribed for 6 months (900 mg weekly for the first four doses, then 1200 mg every 2 weeks). The patient had no relapses or adverse events during and after eculizumab treatment (as of August 2020) and was able to walk unaided; her Expanded Disability Status Scale score improved from 4–5 during 2015–2018 to 2 in 2020 following eculizumab treatment.

Conclusion: Eculizumab shows promise as a treatment for AQP-4 IgG-seronegative NMOSD and further studies are warranted.

RadioGraphics Update: White Matter Diseases with Radiologic-Pathologic Correlation

Editor's Note.-Articles in the RadioGraphics Update section provide current knowledge to supplement or update information found in full-length articles previously published in RadioGraphics. Authors of the previously published article provide a brief synopsis that emphasizes important new information such as technologic advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes. Articles in this section are published solely online and are linked to the original article. ^©RSNA, 2020.

CNS autoimmunity in children: An unwanted wrinkle in a smooth narrative

The emerging paradigm of childhood autoimmune neurological disorders has exploded in recent times due to reliable diagnostic methods and their ease of availability, well-defined diagnostic criteria, and universal awareness about these disorders. The most important aspect of these disorders is a considerable recovery in response to early targeted immunotherapy. If left untreated and/or ill-treated, these can lead to mortality or lifelong morbidity. Autoantibodies can target any part of the central nervous system (CNS), ranging from superficial structures like myelin to deep intracellular ion channels like voltage-gated potassium channels, resulting in contrasting and at times overlapping symptomatology. Though neuroimaging characteristics and serological tests confirm these disorders' diagnosis, it is essential to suspect them clinically and start management before the reports are available for minimizing morbidity and mortality. In the pediatric age group, several metabolic conditions, like mitochondrial disorders and enzyme deficiencies like HMG-CoA-lyase deficiency, can develop neuroimaging patterns similar to those seen in childhood CNS autoimmune disorders and may also show a favorable response to steroids in acute phases. Hence, the clinician must suspect and work up the index patient appropriately. Here, we briefly discuss the pathophysiology, clinical clues, and potential therapeutic targets related to pediatric CNS autoimmune disorders.

Optical Coherence Tomography Angiography of Peripapillary Vessel Density in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder: A Comparative Study

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are demyelinating diseases of the central nervous system, which differ in the pathogenic mechanism. A common clinical presentation of both conditions is optic neuritis (ON). The study aimed to compare the radial peripapillary capillary (RPC) vessel density in MS and NMOSD patients using optical coherence tomography angiography (OCTA). A total of 40 MS patients, 13 NMOSD patients, and 20 controls were included. The average RPC vessel density was significantly lower in ON eyes (MS+ON, NMOSD+ON) than in non-ON eyes (MS−ON, NMOSD−ON) and in MS+ON, MS−ON, NMOSD+ON, and NMOSD−ON compared with the control group. In NMOSD+ON eyes, the vessel density in superior nasal, nasal superior, and inferior sectors was significantly more decreased than in MS+ON eyes. RPC reduction was also observed in inferior nasal and temporal superior sectors in MS−ON eyes compared with NMOSD−ON eyes. In conclusion, our findings indicate that optic neuritis is associated with a more significant RPC vessel density drop in NMOSD than in MS patients, and the predilection to superior and inferior sectors may be useful as a differential diagnostic marker.

Clostridium bolteae is elevated in neuromyelitis optica spectrum disorder in India and shares sequence similarity with AQP4

OBJECTIVE

To understand the role of gut microbiome in influencing the pathogenesis of neuromyelitis optica spectrum disorders (NMOSDs) among patients of south Indian origin.

METHODS

In this case-control study, stool and blood samples were collected from 39 patients with NMOSD, including 17 with aquaporin 4 IgG antibodies (AQP4+) and 36 matched controls. 16S ribosomal RNA (rRNA) sequencing was used to investigate the gut microbiome. Peripheral CD4+ T cells were sorted in 12 healthy controls, and in 12 patients with AQP4+ NMOSD, RNA was extracted and immune gene expression was analyzed using the NanoString nCounter human immunology kit code set.

RESULTS

Microbiota community structure (beta diversity) differed between patients with AQP4+ NMOSD and healthy controls (p < 0.001, pairwise PERMANOVA test). Linear discriminatory analysis effect size identified several members of the microbiota that were altered in patients with NMOSD, including an increase in Clostridium bolteae (effect size 4.23, p 0.00007). C bolteae was significantly more prevalent (p = 0.02) among patients with AQP4-IgG+ NMOSD (n = 8/17 subjects) compared with seronegative patients (n = 3/22) and was absent among healthy stool samples. C bolteae has a highly conserved glycerol uptake facilitator and related aquaporin protein (p59-71) that shares sequence homology with AQP4 peptide (p92-104), positioned within an immunodominant (AQP4 specific) T-cell epitope (p91-110). Presence of C bolteae correlated with expression of inflammatory genes associated with both innate and adaptive immunities and particularly involved in plasma cell differentiation, B cell chemotaxis, and Th17 activation.

CONCLUSION

Our study described elevated levels of C bolteae associated with AQP4+ NMOSD among Indian patients. It is possible that this organism may be causally related to the immunopathogenesis of this disease in susceptible individuals.

Clinical Characteristics of Chinese Male Patients with Aquaporin-4 Antibody-Positive Late-Onset Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVE

Limited studies are available for male patients with anti-aquaporin-4 antibody (AQP4-Ab)-positive late-onset neuromyelitis optica spectrum disease (LONMOSD). The aim of this study was to investigate the clinical characteristics of Chinese male patients with AQP4-Ab-positive LONMOSD.

METHODS

We retrospectively reviewed the medical records of 12 male patients with LONMOSD, 16 male patients with early-onset NMOSD (EONMOSD), and 64 female patients with LONMOSD. These enrolled patients were classified according to the age of onset: LONMOSD (≥50 years of age at onset) versus EONMOSD (<50 years of age at onset). Clinical characteristics and magnetic resonance imaging (MRI) findings were collected. All included patients were positive for AQP4 antibody.

RESULTS

Compared with female LONMOSD patients, male LONMOSD patients had less frequent transverse myelitis (TM) at onset (8.33 vs. 53.13%, p = 0.004) and lower Expanded Disability Status Scale (EDSS) scores (median 1 vs. 4, p = 0.036). Compared with male EONMOSD patients, male LONMOSD patients had a shorter time from onset to diagnosis (0.85 months vs. 6.00 months, p = 0.04).

CONCLUSION

Less common TM at onset, less disease severity, and shorter time from onset to diagnosis probably occur in male LONMOSD patients.

Eculizumab: A Review in Neuromyelitis Optica Spectrum Disorder

The terminal complement protein (C5) inhibitor eculizumab (Soliris^®) is the first agent to be specifically approved in the EU, USA, Canada and Japan for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults who are aquaporin-4 water channel autoantibody (AQP4-IgG) seropositive and (in the EU only) for those with a relapsing course of disease. In the phase III PREVENT trial, eculizumab significantly reduced the risk of adjudicated relapse relative to placebo in patients with AQP4-IgG-seropositive NMOSD, approximately a quarter of whom did not receive concomitant immunosuppressive therapies. The beneficial effect of eculizumab was seen across all patient subgroups analysed and was accompanied by improvements in neurological and functional disability assessments, as well as generic health-related quality of life measures; it was sustained through 4 years of treatment, according to combined data from the PREVENT trial and an interim analysis of its ongoing open-label extension study. The safety profile of eculizumab in AQP4-IgG-seropositive NMOSD was consistent with that seen for the drug in other approved indications. Thus, eculizumab provides an effective, generally well tolerated and approved treatment option for this rare, disabling and potentially life-threatening condition.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease: Current Insights into the Disease Pathophysiology, Diagnosis and Management

Myelin oligodendrocyte glycoprotein (MOG)-associated disease (MOGAD) is a rare, antibody-mediated inflammatory demyelinating disorder of the central nervous system (CNS) with various phenotypes starting from optic neuritis, via transverse myelitis to acute demyelinating encephalomyelitis (ADEM) and cortical encephalitis. Even though sometimes the clinical picture of this condition is similar to the presentation of neuromyelitis optica spectrum disorder (NMOSD), most experts consider MOGAD as a distinct entity with different immune system pathology. MOG is a molecule detected on the outer membrane of myelin sheaths and expressed primarily within the brain, spinal cord and also the optic nerves. Its function is not fully understood but this glycoprotein may act as a cell surface receptor or cell adhesion molecule. The specific outmost location of myelin makes it a potential target for autoimmune antibodies and cell-mediated responses in demyelinating processes. Optic neuritis seems to be the most frequent presenting phenotype in adults and ADEM in children. In adults, the disease course is multiphasic and subsequent relapses increase disability. In children ADEM usually presents as a one-time incident. Luckily, acute immunotherapy is very effective and severe disability (ambulatory and visual) is less frequent than in NMOSD. A critical element of reliable diagnosis is detection of pathogenic serum antibodies MOG with accurate, specific and sensitive methods, preferably with optimized cell-based assay (CBA). MRI imaging can also help in differentiating MOGAD from other neuro-inflammatory disorders. Reports on randomised control trials are limited, but observational open-label experience suggests a role for high-dose steroids and plasma exchange in the treatment of acute attacks, and for immunosuppressive therapies, such as steroids, oral immunosuppressants and rituximab as maintenance treatment. In this review, we present up-to-date clinical, immunological, radiographic, histopathological data concerning MOGAD and summarize the practical aspects of diagnosing and managing patients with this disease.

Safety and efficacy of mycophenolate mofetil in treating neuromyelitis optica spectrum disorders: a protocol for systematic review and meta-analysis

INTRODUCTION

Neuromyelitis optica spectrum disorders (NMOSD) is an inflammatory and heterogeneous astrocyte disorder of the central nervous system with the characteristic of higher incidence in women and Asian people. Most patients with NMOSD have a course of recurrence and remission that is prone to cause paralysis and blindness. Several studies have confirmed the efficacy and promising prospect of mycophenolate mofetil (MMF) in the treatment of NMOSD. Yet its therapeutic effect and safety are controversial. Although there has been two published literature that is relevant to the topic of this study, both of them have certain defects, and they can only provide answers about the efficacy or safety of MMF in the treatment of NMOSD from partial perspectives or conclusions. This research aims to perform a direct and comprehensive systematic review and meta-analysis to evaluate MMF's effectiveness and safety in treating NMOSD.

METHODS AND ANALYSIS

This systematic review will cover all comparative researches, from randomised controlled trials to cohort studies, and case-control study. A relevant literature search will be conducted in PubMed, Web of Science, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database and Chinese Biomedical Literature Database from their inception to 31 June 2020. We will also search registers of clinical trials, potential grey literature and abstracts from conferences. There are no limits on language and publication status. The reporting quality and risk of bias will be assessed by two researchers independently. Expanded Disability Status Scales and annualised relapse rate will be evaluated as the primary outcome. The secondary outcomes will consist of the frequency and severity of adverse events, best-corrected visual acuity, relapse-free rate and time to the next attack. A meta-analysis will be performed using RevMan V.5.3 software provided by the Cochrane Collaboration and Stata V.12.0.

ETHICS AND DISSEMINATION

Because the data used for this systematic review will be exclusively extracted from published studies, ethical approval and informed consent of patients will not be required. The systematic review will be published in a peer-reviewed journal, presented at conferences and will be shared on social media platforms.

PROSPERO REGISTRATION NUMBER

CRD42020164179.

Review of approved NMO therapies based on mechanism of action, efficacy and long-term effects

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Neuromyelitis optica (NMO - including NMO spectrum disorders [NMOSD]) is a devastating disease.

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Up until recently, there was no proven agent to treat to prevent relapses.

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We now have three agents indicated for the treatment of NMO.

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We might suggest the following sequence – 1st line using eculizumab for rapid efficacy and stabilization without effect on the acquired immune system followed by satrilizumab (long term immunomodulation).

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Reserve inebilizumab (immunosuppressant) for breakthrough disease and salvage the severe with AHSCBMT.

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In NMO, control the complement, transition to modulation, and reserve suppression – and salvage the severe with AHSCBMT.

Importance

Neuromyelitis optica (NMO - including NMO spectrum disorders [NMOSD]) is a devastating disease. Eighty-three percent of patients with transverse myelitic (TM) attacks and 67% of patients with optic neuritis (ON) attacks have no or a partial recovery.

Observations

Up until recently, there was no proven agent to treat to prevent relapses. The neuro-immunological community had a dearth of indicated agents for NMOSD. We now have three agents indicated for the treatment of NMO including (eculizumab [Soliris®]), an anti-C5 complement inhibitor, satralizumab (ENSRYNG®), a monoclonal antibody against the IL-6 receptor (IL-6R) that blocks B cell antibody production and inebilizumab (Uplinza®), a monoclonal antibody that binds to the B-cell surface antigen CD19 with subsequent B and plasmablast cell lymphocytolysis with decreasing antibody production. Autologous hematopoietic stem cell bone marrow transplantation (AHSCBMT) has also been used. How do we sequence NMO therapies with the understanding of the acuteness and severity of the disease, the individual mechanism of action (MOA) and rapidity of onset of action, onset of efficacy and long-term safety of each agent?

Conclusions and Relevance

We might suggest the following sequence – 1st line using eculizumab for rapid efficacy and stabilization without effect on the acquired immune system followed by satrilizumab (long term immunomodulation). Reserve inebilizumab (immunosuppressant) for breakthrough disease and salvage the severe with AHSCBMT. In NMO, control the complement, transition to modulation, and reserve suppression – and salvage the severe with AHSCBMT.