A serum autoantibody marker of neuromyelitis optica: distinction from multiple sclerosis

Aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders: progress of experimental models based on disease pathogenesis

Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction. To date, no effective treatment exists as the exact causative mechanism remains unknown. Therefore, experimental models of neuromyelitis optica spectrum disorders are essential for exploring its pathogenesis and in screening for therapeutic targets. Since most patients with neuromyelitis optica spectrum disorders are seropositive for IgG autoantibodies against aquaporin-4, which is highly expressed on the membrane of astrocyte endfeet, most current experimental models are based on aquaporin-4-IgG that initially targets astrocytes. These experimental models have successfully simulated many pathological features of neuromyelitis optica spectrum disorders, such as aquaporin-4 loss, astrocytopathy, granulocyte and macrophage infiltration, complement activation, demyelination, and neuronal loss; however, they do not fully capture the pathological process of human neuromyelitis optica spectrum disorders. In this review, we summarize the currently known pathogenic mechanisms and the development of associated experimental models in vitro, ex vivo, and in vivo for neuromyelitis optica spectrum disorders, suggest potential pathogenic mechanisms for further investigation, and provide guidance on experimental model choices. In addition, this review summarizes the latest information on pathologies and therapies for neuromyelitis optica spectrum disorders based on experimental models of aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders, offering further therapeutic targets and a theoretical basis for clinical trials.

Biomarkers for neuromyelitis optica: a visual analysis of emerging research trends

Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis. Over the past 20 years, the search for biomarkers for neuromyelitis optica has been ongoing. Here, we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica. Research in this area is consistently increasing, with China and the United States leading the way on the number of studies conducted. The Mayo Clinic is a highly reputable institution in the United States, and was identified as the most authoritative institution in this field. Furthermore, Professor Wingerchuk from the Mayo Clinic was the most authoritative expert in this field. Keyword analysis revealed that the terms "neuromyelitis optica" (261 times), "multiple sclerosis" (220 times), "neuromyelitis optica spectrum disorder" (132 times), "aquaporin 4" (99 times), and "optical neuritis" (87 times) were the most frequently used keywords in literature related to this field. Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis. Furthermore, aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder. Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarker for myelin oligodendrocyte glycoprotein antibody-associated disease. Recent biomarkers for neuromyelitis optica include cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein, serum astrocyte damage biomarkers like FAM19A5, serum albumin, and gamma-aminobutyric acid. The latest prospective clinical trials are exploring the potential of these biomarkers. Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder. The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity, specificity, and safety for the accurate diagnosis of neuromyelitis optica.

Efficacy and safety of mycophenolate mofetil for steroid reduction in neuromyelitis optica spectrum disorder: a prospective cohort study

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory disease that can affect multiple generations and cause complications with long-term prednisolone treatment. This study aimed to evaluate the efficacy and safety of mycophenolate mofetil (MMF) in preventing NMOSD relapse while reducing prednisolone dosage. The trial involved nine patients with NMOSD who received MMF along with prednisolone dose reduction. MMF was effective in achieving prednisolone dose reduction without relapse in 77.8% of patients, with a significant decrease in mean annualized relapse rate. All adverse events were mild. The findings suggest that MMF could be a viable treatment option for middle-aged and older patients who require steroid reduction.Clinical trial registration number: jRCT, jRCTs051180080. Registered February 27th, 2019-retrospectively registered, https://jrct.niph.go.jp/en-latest-detail/jRCTs051180080.

Emergent Management of Central Nervous System Demyelinating Disorders

OBJECTIVE

This article reviews the various conditions that can present with acute and severe central nervous system demyelination, the broad differential diagnosis of these conditions, the most appropriate diagnostic workup, and the acute treatment regimens to be administered to help achieve the best possible patient outcomes.

LATEST DEVELOPMENTS

The discovery of anti-aquaporin 4 (AQP4) antibodies and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in the past two decades has revolutionized our understanding of acute demyelinating disorders, their evaluation, and their management.

ESSENTIAL POINTS

Demyelinating disorders comprise a large category of neurologic disorders seen by practicing neurologists. In the majority of cases, patients with these conditions do not require care in an intensive care unit. However, certain disorders may cause severe demyelination that necessitates intensive care unit admission because of numerous simultaneous multifocal lesions, tumefactive lesions, or lesions in certain brain locations that lead to acute severe neurologic dysfunction. Intensive care may be necessary for the management and prevention of complications for patients who have severely altered mental status, rapidly progressive neurologic worsening, elevated intracranial pressure, severe cerebral edema, status epilepticus, or respiratory failure.

Analysis of the initial orbital MRI in aquaporin-4 antibody-positive optic neuritis (AQP4-ON): lesion location and lesion length can be predictive of visual prognosis

PURPOSE

Despite mounting evidence indicating that aquaporin-4 antibody-positive optic neuritis (AQP4-ON) presents a less favorable prognosis than other types of optic neuritis, there exists substantial heterogeneity in the prognostic outcomes within the AQP4-ON cohort. Considering the persistent debate over the role of MRI in assessing the prognosis of optic neuritis, we aim to investigate the correlation between the MRI appearance and long-term visual prognosis in AQP4-ON patients.

METHODS

We retrospectively reviewed the ophthalmological and imaging data of AQP4-ON patients admitted to our Neuro-ophthalmology Department from January 2015 to March 2018, with consecutive follow-up visits for a minimum of 3 years.

RESULTS

A total of 51 AQP4-ON patients (59 eyes) meeting the criteria were enrolled in this research. After assessing the initial orbital MR images of each patient at the first onset, we observed the involvement of the canalicular segment (p < 0.001), intracranial segment (p = 0.004), optic chiasm (p = 0.009), and the presence of LEON (p = 0.002) were significantly different between recovery group and impairment group. For quantitative measurement, the length of the lesions is significantly higher in the impairment group (20.1 ± 9.3 mm) than in the recovery group (12.5 ± 5.3 mm) (p = 0.001).

CONCLUSION

AQP4-ON patients with involvement of canalicular, intracranial segment and optic chiasm of the optic nerve, and the longer range of lesions threaten worse vision prognoses. Timely MR examination during the initial acute phase can not only exclude the intracranial or orbital mass lesions but also indicate visual prognosis in the long term.

Interest of rare autoantibodies in autoimmune encephalitis and paraneoplastic neurological syndromes: the utility (or futility) of rare antibody discovery

PURPOSE OF REVIEW

The increasing recognition and diagnosis of autoimmune encephalitis (AE) and paraneoplastic neurological syndromes (PNS) is partly due to neural autoantibody testing and discovery. The past two decades witnessed an exponential growth in the number of identified neural antibodies. This review aims to summarize recent rare antibody discoveries in the context of central nervous system (CNS) autoimmunity and evaluate the ongoing debate about their utility.

RECENT FINDINGS

In the last 5 years alone 15 novel neural autoantibody specificities were identified. These include rare neural antibody biomarkers of autoimmune encephalitis, cerebellar ataxia or other movement disorders, including multifocal presentations.

SUMMARY

Although the clinical applications of these rare antibody discoveries may be limited by the low number of positive cases, they still provide important diagnostic, prognostic, and therapeutic insights.

Moving towards a new era for the treatment of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) include a rare group of autoimmune conditions that primarily affect the central nervous system. They are characterized by inflammation and damage to the optic nerves, brain and spinal cord, leading to severe vision impairment, locomotor disability and sphynteric disturbances. In the majority of cases, NMOSD arises due to specific serum immunoglobulin G (IgG) autoantibodies targeting aquaporin 4 (AQP4-IgG), which is the most prevalent water-channel protein of the central nervous system. Early diagnosis and treatment are crucial to manage symptoms and prevent long-term disability in NMOSD patients. NMOSD were previously associated with a poor prognosis. However, recently, a number of randomized controlled trials have demonstrated that biological therapies acting on key elements of NMOSD pathogenesis, such as B cells, interleukin-6 (IL-6) pathway, and complement, have impressive efficacy in preventing the occurrence of clinical relapses. The approval of the initial drugs marks a revolutionary advancement in the treatment of NMOSD patients, significantly transforming therapeutic options and positively impacting their prognosis. In this review, we will provide an updated overview of the key immunopathological, clinical, laboratory, and neuroimaging aspects of NMOSD. Additionally, we will critically examine the latest advancements in NMOSD treatment approaches. Lastly, we will discuss key aspects regarding optimization of treatment strategies and their monitoring.

The diagnostic performance of AI-based algorithms to discriminate between NMOSD and MS using MRI features: A systematic review and meta-analysis

BACKGROUND

Magnetic resonance imaging [MRI] findings in Neuromyelitis optica spectrum disorder [NMOSD] and Multiple Sclerosis [MS] patients could lead us to discriminate toward them. For instance, U-fiber and Dawson's finger-type lesions are suggestive of MS, however linear ependymal lesions raise the possibility of NMOSD. Recently, artificial intelligence [AI] models have been used to discriminate between NMOSD and MS based on MRI features. In this study, we aim to systematically review the capability of AI algorithms in NMOSD and MS discrimination based on MRI features.

METHOD

We searched PubMed, Scopus, Web of Sciences, Embase, and IEEE databases up to August 2023. All studies that used AI-based algorithms to discriminate between NMOSD and MS using MRI features were included, without any restriction in time, region, race, and age. Data on NMOSD and MS patients, Aquaporin-4 antibodies [AQP4-Ab] status, diagnosis criteria, performance metrics (accuracy, sensitivity, specificity, and AUC), artificial intelligence paradigm, MR imaging, and used features were extracted. This study is registered with PROSPERO, CRD42023465265.

RESULTS

Fifteen studies were included in this systematic review, with sample sizes ranging between 53 and 351. 1,362 MS patients and 1,118 NMOSD patients were included in our systematic review. AQP4-Ab was positive in 94.9% of NMOSD patients in 9 studies. Eight studies used machine learning [ML] as a classifier, while 7 used deep learning [DL]. AI models based on only MRI or MRI and clinical features yielded a pooled accuracy of 82% (95% CI: 78-86%), sensitivity of 83% (95% CI: 79-88%), and specificity of 80% (95% CI: 75-86%). In subgroup analysis, using only MRI features yielded an accuracy, sensitivity, and specificity of 83% (95% CI: 78-88%), 81% (95% CI: 76-87%), and 84% (95% CI: 79-89%), respectively.

CONCLUSION

AI models based on MRI features showed a high potential to discriminate between NMOSD and MS. However, heterogeneity in MR imaging, model evaluation, and reporting performance metrics, among other confounders, affected the reliability of our results. Well-designed studies on multicentric datasets, standardized imaging and evaluation protocols, and detailed transparent reporting of results are needed to reach optimal performance.

An uncommon cause of vertigo: Neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon antibody-mediated disease of the central nervous system. Its classic presentation includes long segments of spinal cord inflammation, optic neuritis with or without intractable vomiting, and hiccups. Here, we described a case of a 39-year-old woman with an atypical presentation of vertigo, which was finally diagnosed as NMOSD by a positive serum aquaporin-4 antibody.

Epidemiology of aquaporin-4-IgG-positive NMOSD in Sardinia

PURPOSE

The Italian Island of Sardinia (population, 1,578,146) is recognized for the high risk of multiple sclerosis (MS) but the epidemiological burden of other less common demyelinating diseases of the central nervous system (CNS), such as aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD), is unknown. In this study, we determined the incidence and prevalence of AQP4-IgG+NMOSD in Sardinia over a ten-year study period (2013-2022).

METHODS

Patients with a diagnosis of AQP4-IgG+NMOSD (per 2015 IPND diagnostic criteria) were retrospectively identified using two sources: (1) Archives of the reference and only laboratory for AQP4-IgG testing in Sardinia; and (2) medical records of the four MS units in the island. Incidence (January 2013-December 2022) and prevalence (December 31, 2022) were calculated.

RESULTS

A total of 45 cases were included: incident, 31; prevalent, 41. The median age (range) at disease presentation was 51 (6-78) years; female/male ratio was 9:1. The crude (95 % CI) incidence and prevalence were 1.9 (1.3-2.7) per million and 2.6 (1.9-3.5) per 100,000, respectively. Prevalence increased from 2013 (1.1 per 100,000) to 2022 (2.6 per 100,000); p = 0.002. After age-standardization to the world, incidence and prevalence (95 % CI) decreased to 1.3 (0.7-2) per million and 1.8 (1.3-2.3) per 100,000, respectively. Coexisting immune-mediated disorders, mostly autoimmune thyroiditis, were reported in 50 % of patients.

CONCLUSIONS

The epidemiology of AQP4-IgG+NMOSD in Sardinia is overall in line with other Caucasian populations. The high MS risk in the island seems disease-specific and not associated with an increased risk of other CNS demyelinating disorders, confirming different pathophysiology.

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.

Newly emerging type B insulin resistance (TBIR) during treatment with eculizumab for AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD): fatal outcome

BACKGROUND

Aquaporin-4 immunoglobulin G (AQP4-IgG) antibody-positive neuromyelitis optica spectrum disorders (NMOSD) are frequently associated with other autoimmune disorders, including systemic lupus erythematosus (SLE). Eculizumab (ECU) is a highly effective long-term treatment for NMOSD. However, ECU is known to increase significantly the risk of infection with encapsulated bacteria and sepsis. Recently, increased insulin resistance (IR) in patients with NMOSD has been suggested. Type B IR (TBIR) is a rare autoimmune condition often accompanying or preceding SLE. TBIR has not yet been reported in NMOSD.

OBJECTIVE

To report an ECU-treated patient with AQP4-IgG-positive NMOSD who developed fatal septic complications after the emergence of TBIR.

METHODS

Description of the clinical course over a period of 8 years.

RESULTS

A female patient was diagnosed with NMOSD at the age of 16 years. A variety of disease-modifying drugs failed to achieve sufficient disease control, resulting in severe tetraparesis. Treatment with ECU was started 6 years after NMOSD diagnosis and stabilized the disease. The patient developed TBIR 8 months after initiation of ECU therapy. Following high-dose intravenous methylprednisolone therapy for a clinical relapse and three further courses of ECU, the patient was admitted with severe pneumonia caused by the encapsulated bacterium Klebsiella pneumoniae and hypoglycemia. Despite multimodal therapy, the patient died from sepsis-related multiorgan failure 18 months after initiation of ECU.

CONCLUSIONS

TBIR should be considered as differential diagnosis in patients with NMOSD presenting with disturbed glucose metabolism, irrespective of the presence of SLE. More real-world data are needed on the risk/benefit ratio of ECU treatment in patients who have co-existing autoimmune comorbidities that may compromise immune function. Strategies to mitigate the risk of serious infection in patients treated with ECU are discussed.

Identification of potential biomarkers for neuromyelitis optica by quantitative proteomics

OBJECTIVE

Neuromyelitis optica (NMO) was a serious autoimmune inflammatory condition affecting the central nervous system. Currently, there was a lack of diagnostic biomarkers for AQP4-IgG-negative NMO patients.

METHODS

A comparative proteomic analysis was conducted on the CSF of 10 patients with NMO and 10 patients with non-inflammatory neurological disorders (NND) using tandem mass tagging technology. Differentially expressed proteins (DEPs) were analyzed using bioinformatic methods. The candidate proteins were then validated through ELISAs in a subsequent cohort of 160 samples, consisting of paired CSF and plasma samples from 50 NMO patients, CSF samples from 30 NND patients, and plasma samples from 30 healthy individuals.

RESULTS

We identified 389 proteins via proteomics, screening 79 DEPs. NCAM1, SST and AHSG were selected as candidate molecules for further validation. Compared to NND patients, there were decreased levels of AHSG in CSF and increased levels of NCAM1 and SST in NMO patients. The ELISA results revealed significantly higher levels of AHSG, SST and NCAM1 in the CSF of the NMO group compared to the NND group. Similarly, the serum levels of these three proteins were also higher in the NMO group compared to the healthy control group. It was found that serum NCAM1 levels significantly decreased in patients with non-relapsed NMO compared to patients with relapsed NMO and CSF NCAM1 level increased in patients with bilateral NMO compared to patients with unilateral NMO. Furthermore, CSF SST levels increased in AQP4 antibody-positive NMO patients compared to AQP4 antibody-negative patients.

INTERPRETATION

CSF NCAM1, serum NCAM1 and serum SST may serve as potential biomarkers for NMO patients and aid in the diagnosis of AQP4 antibody-negative NMO patients.

High-Intensity Gait Training in an Individual With Neuromyelitis Optica and Research Recommendations for Individuals With Multiple Sclerosis

BACKGROUND

Neuromyelitis optica (NMO), similar to multiple sclerosis (MS), is an autoimmune disorder affecting the central nervous system. In people with central nervous system diagnoses, high-intensity gait training (HIGT) can support neuroplasticity, improving functional mobility. While low- to moderate-intensity exercise is beneficial in improving outcomes in individuals with NMO and MS, the impact of HIGT has not been thoroughly explored. This case study explores the safety and efficacy of HIGT in an individual with NMO.

METHODS

A 43-year-old man with NMO participated in a HIGT program utilizing the least amount of body weight support necessary to achieve a target heart rate of 60% to 80% of heart rate reserve or a Borg Rating of Perceived Exertion score of 15 to 17 during an in-patient rehabilitation stay. Interventions incorporated stair training, gait variances, and virtual reality.

RESULTS

The patient successfully completed a 90-minute training session 4 to 7 times per week for 6 weeks following a HIGT regimen for 40% to 60% of each session. Meaningful gains in bed mobility, transfers, and gait allowed for discharge to his home.

CONCLUSIONS

This case suggests that HIGT in patients with NMO can be safe and effective in improving functional mobility. Due to the similarities between NMO and MS, this case provides a framework to assist clinicians in developing a HIGT plan of care for individuals with MS. Additional research is needed to clarify HIGT parameters, including intensity and duration, to improve functional mobility in individuals with MS.

Clinical features and visual prognosis of very late-onset neuromyelitis optica spectrum disorder-related optic neuritis

BACKGROUND

Very late-onset neuromyelitis optica spectrum disorder-related optic neuritis is limited to a few case reports.

OBJECTIVE

To investigate the clinical features and visual prognosis of very late-onset neuromyelitis optica spectrum disorder-related optic neuritis.

METHODS

This study evaluated 22 patients with first-onset optic neuritis and fulfilled the 2015 diagnosis criteria for neuromyelitis optica spectrum disorders.

RESULTS

The mean age at optic neuritis onset was 73.91 ± 4.71 (range: 70-82) years with a female predominance (81.8%; ratio: 4.5:1). Antinuclear antibody seropositivity and seronegativity were identified in 12 (55.5%) and 10 (45.5%) patients, respectively. Severe visual loss persisted in 19 (19/42, 45.3%) eyes at the last follow-up. Although patients with antinuclear antibody seropositivity had a significantly higher frequency of attacks (P = 0.015), but they had a longer median time to reach severe visual loss (37 vs. 26 months; log-rank test, P = 0.023). Multivariate logistic regression analysis revealed antinuclear antibody seropositivity (hazard ratio = 4.849, 95% confidence interval: 1.309-17.965, P = 0.018) as a good predictor of visual acuity improvement.

CONCLUSION

Patients with very late-onset neuromyelitis optica spectrum disorder-related optic neuritis may develop severe optic neuritis, and those with antinuclear antibody seronegativity have a similar clinical presentation but worse outcome than those with seropositivity.

Multiple Sclerosis Part 1: Essentials and the McDonald Criteria

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) characterized by relapsing-remitting or progressive neurologic symptoms and focal white matter lesions. The hallmark of the disease is the dissemination of CNS lesions in space and time, which is defined by the McDonald criteria. MRI is an essential diagnostic and prognostic biomarker for MS which can evaluate the entire CNS. MS mimics must be excluded before a diagnosis of MS is made.

Use of Complementary and Alternative Medicine in Patients With Idiopathic Inflammatory Demyelinating Diseases of the Central Nervous System: A Cross-Sectional Study in Thailand

Background

Complementary and alternative medications (CAM) are common among patients with multiple sclerosis (MS) for physical and psychological support. However, there is insufficient data regarding the application of CAM in the different cultures and beliefs of each community as well as patient's status.

Objective

To evaluate the prevalence and modalities of the use of CAM among patients with central nervous system idiopathic inflammatory demyelinating diseases (CNS-IIDD) in a tertiary care hospital.

Methods

A cross-sectional study was conducted at Siriraj Hospital from June to December 2021 involving patients with MS, neuromyelitis optic spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), idiopathic transverse myelitis (iTM), and optic neuritis (ON) to examine the prevalence and mode of CAM use and its correlation with patient characteristics.

Results

There were 107 patients. The diagnoses were MS (38), NMOSD (55), MOGAD (5), iTM (7), and ON (2). Most of the patients were female (89.7%), and 61.7% were diagnosed over 5 years. The mean Expanded Disability Status Scale was 2.63 (S.D., 2.38), and the median ambulation index was 0 (range 0-8.5). There were 68 patients (63.6%) with a history of CAM use for at least 3 months, while those with current use decreased to 62 (58.5%). Vitamins and minerals were the most commonly used, particularly vitamin D (97.1%) and calcium (47.7%). Both treatments were primarily prescribed (95.3%) rather than self-administered (24.3%). The main reasons for the use of CAM were to strengthen their health (48.6%) and relieve existing symptoms (28.0%).

Conclusions

The use of CAM is common among patients with Thai CNS-IIDD. Further exploration of patient perspectives and preferences regarding CAM usage may contribute to a more comprehensive management approach for patients with CNS-IIDD.

Stage-dependent immunity orchestrates AQP4 antibody-guided NMOSD pathology: a role for netting neutrophils with resident memory T cells in situ

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood-brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive 'stage-dependent' investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under "standby" conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.

Cognitive impairment and its association with clinical variables in Mexican persons with neuromyelitis optica spectrum disorder

INTRODUCTION

Cognitive impairment has a substantial impact on the daily function of people living with demyelinating diseases. However, the study of cognitive failures and their association with clinical variables in people suffering from neuromyelitis optica spectrum disorder (NMOSD) has been scarce, especially in the latin american (Mexican) population at early and middle stages of the disease.

METHOD

We applied the Rao's Brief Repeatable Battery of Neuropsychological tests and obtained data of lesion burden through magnetic resonance imaging (MRI), expression of AQPQ4-IgG antibodies, and degree of disability in 30 patients with NMOSD and 30 healthy participants as a control group.

RESULTS

About half of the NMOSD patients (47%) showed some degree of cognitive impairment, especially in the executive domain compared to the control group. Executive function scores were positively associated with the degree of physical disability. We found no associations between cognitive dysfunction and disease duration, AQPQ4-IgG antibodies, lesion burden, nor depression.

CONCLUSIONS

Executive functioning impairment is present in NMOSD and may predict the degree of functional disability in patients. Cognitive failures were not associated with immunological or radiological data, which emphasizes the relevance of applying systematic neuropsychological assessments in this clinical population.

The relationship between serum astroglial and neuronal markers and AQP4 and MOG autoantibodies

BACKGROUND

Certain demyelinating disorders, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) exhibit serum autoantibodies against aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG). The variability of the autoantibody presentation warrants further research into subtyping each case.

METHODS

To elucidate the relationship between astroglial and neuronal protein concentrations in the peripheral circulation with occurrence of these autoantibodies, 86 serum samples were analyzed using immunoassays. The protein concentration of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL) and tau protein was measured in 3 groups of subcategories of suspected NMOSD: αAQP4 positive (n = 20), αMOG positive (n = 32) and αMOG/αAQP4 seronegative (n = 34). Kruskal-Wallis analysis, univariate predictor analysis, and multivariate logistic regression with ROC curves were performed.

RESULTS

GFAP and NFL concentrations were significantly elevated in the αAQP4 positive group (p = 0.003; p = 0.042, respectively), and tau was elevated in the αMOG/αAQP4 seronegative group (p < 0.001). A logistic regression model to classify serostatus was able to separate αAQP4 seropositivity using GFAP + tau, and αMOG seropositivity using tau. The areas under the ROC curves (AUCs) were 0.77 and 0.72, respectively. Finally, a combined seropositivity versus negative status logistic regression model was generated, with AUC = 0.80.

CONCLUSION

The 3 markers can univariately and multivariately classify with moderate accuracy the samples with seropositivity and seronegativity for αAQP4 and αMOG.

Sex hormones and neuromyelitis optica spectrum disorder: a bidirectional Mendelian randomization study

BACKGROUND

Females are considered to have an increased susceptibility to neuromyelitis optica spectrum disorder (NMOSD) than males, especially aquaporin-4 (AQP4) antibody positive NMOSD, indicating that sex hormones may be involved in the NMOSD pathogenesis. However, the causality between sex hormones and NMOSD still remains unclear.

METHODS

Based on the genome-wide association study (GWAS) data of three sex hormones (estradiol (E2), progesterone (PROG) and bioavailable testosterone (BAT)), sex hormone-binding globulin (SHBG), age of menarche, age of menopause, and NMOSD (total, AQP4 + and AQP4 -), we performed a two-sample bidirectional Mendelian randomization (MR) study. Sex-stratified GWAS data of E2, PROG, BAT, and SHBG was obtained for gender-specific MR analysis. Causal inferences were based on the inverse variance weighted method, MR-Egger regression, and weighted median method. The reverse MR analysis was also performed to assess the impact of NMOSD on hormone levels.

RESULTS

PROG in females had aggravative effects on NMOSD (P < 0.001), especially AQP4 - NMOSD (P < 0.001). In the reverse MR analysis, total NMOSD was found to decrease the level of BAT (P < 0.001) and increase the level of SHBG (P = 0.001) in females.

CONCLUSION

Findings of this MR analysis revealed mutual causal associations between sex hormones and NMOSD, which provided novel perspectives about the gender-related pathogenesis of NMOSD.

Body fluid markers for multiple sclerosis and differential diagnosis from atypical demyelinating disorders

INTRODUCTION

Body fluid markers could be helpful to predict the conversion into clinically definite multiple sclerosis (MS) in people with a first demyelinating event of the central nervous system (CNS). Consequently, biomarkers such as oligoclonal bands, which are integrated in the current MS diagnostic criteria, could assist early MS diagnosis.

AREAS COVERED

This review examines existing knowledge on a broad spectrum of body fluid markers in people with a first CNS demyelinating event, explores their potential to predict conversion to MS, to assess MS disease activity, as well as their utility to differentiate MS from atypical demyelinating disorders such as neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein associated disease.

EXPERT OPINION

This field of research has shown a dramatic increase of evidence, especially in the last decade. Some biomarkers are already established in clinical routine (e.g. oligoclonal bands) while others are currently implemented (e.g. kappa free light chains) or considered as breakthroughs (e.g. neurofilament light). Determination of biomarkers poses challenges for continuous monitoring, especially if exclusively detectable in cerebrospinal fluid. A handful of biomarkers are measurable in blood which holds a significant potential.

Asymptomatic spinal lesions in patients with AQP4-IgG-positive NMOSD: A real-world cohort study

OBJECTIVE

This study aims to explore the frequency and influencing factors of asymptomatic spinal lesions (ASLs) and their impact on subsequent relapses in patients with AQP4-IgG-positive NMOSD (AQP4-NMOSD) in a real-world setting.

METHODS

We retrospectively reviewed clinical information and spinal MRI data from AQP4-NMOSD patients who had at least one spinal cord MRI during their follow-ups. Kaplan-Meier curves and Cox proportional hazards models were employed to ascertain potential predictors of remission ASLs and to investigate factors associated with subsequent relapses.

RESULTS

In this study, we included 129 patients with AQP4-NMOSD and reviewed 173 spinal MRIs during attacks and 89 spinal MRIs during remission. Among these, 6 ASLs (3.5%) were identified during acute attacks, while 8 ASLs (9%) were found during remission. Remission ASLs were linked to the use of immunosuppressive agents, particularly conventional ones, whereas no patients using rituximab developed ASLs (p = 0.005). Kaplan-Meier curve analysis indicated that patients with ASLs had a significantly higher relapse risk (HR = 4.658, 95% CI: 1.519-14.285, p = 0.007) compared to those without. Additionally, the use of mycophenolate mofetil (HR = 0.027, 95% CI: 0.003-0.260, p = 0.002) and rituximab (HR = 0.035, 95% CI: 0.006-0.203, p < 0.001) significantly reduced the relapse risk. However, after accounting for other factors, the presence of ASLs did not exhibit a significant impact on subsequent relapses (HR = 2.297, 95% CI: 0.652-8.085, p = 0.195).

INTERPRETATION

ASLs may be observed in patients with AQP4-NMOSD. The presence of ASLs may signify an underlying inflammatory activity due to insufficient immunotherapy. The administration of immunosuppressive agents plays a key role in the presence of remission ASLs and the likelihood of subsequent relapses.

Retinal structural and microvascular deterioration independent of optic neuritis in aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders: An optical coherence tomography angiography study

PURPOSE

To assess the retinal structural and microvascular change in aquaporin-4 antibody (AQP4) positive neuromyelitis optica spectrum disorder (NMOSD) patients and the correlation with clinical features.

METHODS

A cross-sectional study was performed with optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) to measure retinal structure and microvascular parameters in AQP4 positive NMOSD patients.

RESULTS

Sixty-two NMOSD patients (44 eyes with ON, NMOSD+ON; 77 eyes without ON, NMOSD-ON) and 62 healthy controls (HC, 124 eyes) were included. BCVA was worse in NMOSD patients compared to HC (p<0.001). Peripapillary retinal nerve fiber layer (pRNFL, p<0.001) and ganglion cell complex (GCC, p<0.001) was thinner in NMOSD+ON eyes compared to NMOSD-ON eyes and HC. Compared to HC, pRNFL (p = 0.002) and GCC (p = 0.001) was thinner in NMOSD-ON eyes. The vessel density (VD) in superficial capillary plexus (SCP, NMOSD+ON vs HC p<0.001, NMOSD-ON vs HC p = 0.002) and radial peripapillary capillary (RPC, NMOSD+ON vs HC p<0.001, NMOSD-ON vs HC p = 0.001) were also lower in NMOSD patients than HC independent of the history of ON. ON frequency and BCVA were correlated with the thickness of pRNFL and GCC, and VD in SCP and RPC (all p<0.001). EDSS was correlated with thickness of GCC (p = 0.008), and VD in SCP (p = 0.013), DCP (p<0.001) and RPC (p = 0.009).

CONCLUSIONS

Subclinical degradation of retinal structure and microvasculature was found in NMOSD patients before the occurrence of ON, and was correlated with clinical disability. Retinal parameter might be a tool to estimate the disease progression and investigate the pathogenesis of NMOSD.

Time to Disability Milestones and Annualized Relapse Rates in NMOSD and MOGAD

OBJECTIVE

To investigate accumulation of disability in neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) in a changing treatment landscape. We aimed to identify risk factors for the development of disability milestones in relation to disease duration, number of attacks, and age.

METHODS

We analyzed data from individuals with NMOSD and MOGAD from the German Neuromyelitis Optica Study Group registry. Applying survival analyses, we estimated risk factors and computed time to disability milestones as defined by the Expanded Disability Status Score (EDSS).

RESULTS

We included 483 patients: 298 AQP4-IgG+ NMOSD, 52 AQP4-IgG-/MOG-IgG- NMOSD patients, and 133 patients with MOGAD. Despite comparable annualized attack rates, disability milestones occurred earlier and after less attacks in NMOSD patients than MOGAD patients (median time to EDSS 3: AQP4-IgG+ NMOSD 7.7 (95% CI 6.6-9.6) years, AQP4-IgG-/MOG-IgG- NMOSD 8.7) years, MOGAD 14.1 (95% CI 10.4-27.6) years; EDSS 4: 11.9 (95% CI 9.7-14.7), 11.6 (95% lower CI 7.6) and 20.4 (95% lower CI 14.1) years; EDSS 6: 20.1 (95% CI 16.5-32.1), 20.7 (95% lower CI 11.6), and 37.3 (95% lower CI 29.4) years; and EDSS 7: 34.2 (95% lower CI 31.1) for AQP4-IgG+ NMOSD). Higher age at onset increased the risk for all disability milestones, while risk of disability decreased over time.

INTERPRETATION

AQP4-IgG+ NMOSD, AQP4-IgG-/MOG-IgG- NMOSD, and MOGAD patients show distinctive relapse-associated disability progression, with MOGAD having a less severe disease course. Investigator-initiated research has led to increasing awareness and improved treatment strategies appearing to ameliorate disease outcomes for NMOSD and MOGAD. ANN NEUROL 2024;95:720-732.

Characteristics of recurrence risk perception and coping strategies in patients with neuromyelitis optica spectrum disorder: A qualitative study

BACKGROUND

Although neuromyelitis optica spectrum disorder (NMOSD) has high recurrence and disability rates, cases of relapses can be recognized, and timely intervention can be provided if the risk of relapse is properly perceived. However, there have been no studies to explore patients' perceptions of recurrence risk and coping strategies. This study aimed to explore the characteristics of relapse risk perception and coping strategies of patients with NMOSD.

METHODS

We adopted the phenomenological method of qualitative research. Face-to-face, semi-structured in-depth interviews were conducted with 15 patients with NMOSD. The interview data were then analyzed using the Colaizzi seven-step analysis.

RESULTS

The analysis revealed five major themes. The first theme was the 'perception of possibility of relapse', which included subjectively underestimating the likelihood of relapse and shifted from underestimation to overestimation; the second theme was 'relapse warning signs perception'; the third theme was 'perception of relapse triggers', which included understanding relapse triggers, potential misconceptions about relapse triggers, and no identifiable cause of recurrence; the fourth theme was 'perception of the relapse consequences', encompassing severe impairment of body structure and function, prominent psychological problems, limited family roles and social functions, and heavy financial burden; and the final theme was 'relapse risk coping strategies', which included actively yearning for and seeking information support, recurrence risk prevention/management, limitations of coping strategies.

CONCLUSIONS

This study's findings revealed that newly diagnosed patients as well as those who relapsed subjectively underestimated the likelihood of relapse before they had experienced multiple (two or more) relapses. In contrast, patients who had experienced multiple relapses had transitioned from initial underestimation to subsequent overestimation. Additionally, patients' compliance with medication was identified as a relapse-risk behaviors that was very manageable. The occurrence of relapse is associated with significant and extensive adverse effects on patients. Consequently, patients are eager to communicate with their healthcare providers regarding treatment planning and relapse management.

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.

Inhibition of repulsive guidance molecule-a ameliorates compromised blood-spinal cord barrier integrity associated with neuromyelitis optica in rats

The influx of pathogenic aquaporin-4 antibodies (AQP4-Abs) across the blood-spinal cord barrier (BSCB) is crucial for the development and exacerbation of neuromyelitis optica (NMO). We examined whether prophylactic intravenous administration of anti-repulsive guidance molecule-a antibodies (RGMa-Abs) has disease-modifying effects on BSCB dysfunction using an NMO model elicited by peripheral administration of AQP4-Abs to rats. RGMa-Ab treatment attenuated the acute exacerbation of perivascular astrocytopathy in the spinal cord and clinical symptoms, which were highly correlated with neurofilament light chain levels in both the cerebrospinal fluid (CSF) and serum. Additionally, RGMa-Ab treatment suppressed the expression of proinflammatory cytokines/chemokines and the infiltration of inflammatory cells into the spinal cord. CSF analysis of NMO rats revealed that RGMa-Ab treatment improved the CSF/serum albumin ratio and suppressed AQP4-Abs influx. RGMa inhibition using RGMa-Abs is suggested as a potential therapeutic option for BSCB dysfunction associated with NMO.

Clinical profile and challenges faced in the management of optic neuritis: the Indian scenario

PURPOSE

Optic neuritis (ON) is a relatively common ophthalmic disease that has recently received renewed attention owing to immunological breakthroughs. We studied the profile of patients with ON with special reference to antibody-mediated ON and the challenges faced in its management.

METHODS

Case records of patients with ON presenting to a tertiary eye-care center in South India were analyzed. Data on demographics, presenting visual acuity (VA), clinical features, seropositivity for aquaporin-4 immunoglobulin G (AQP4-IgG) and myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG), details of magnetic resonance imaging (MRI) of orbits and brain, and treatment were collected.

RESULTS

Among 138 cases with acute ON, male: female ratio was 1:2. Isolated ON was present in 41.3% of cases. Antibody testing of sera was performed in 68 patients only due to financial limitations. Among these, 48.5% were MOG-IgG-seropositive, 11.76% were AQP4-IgG-seropositive, and 30.88% samples were double seronegative. Other causes included multiple sclerosis (n = 4), lactational ON (n = 4), tuberculosis (n = 2), invasive perineuritis (n = 2), COVID-19 vaccination (n = 2), and COVID-19 (n = 1). The mean presenting best corrected visual acuity (BCVA) was 1.31 ± 1.16 logMAR (logarithm of the minimum angle of resolution). The mean BCVA at 3 months was 0.167 ± 0.46 logMAR. Only initial VA ≤ 'Counting fingers' (CF) had a significant association with the visual outcome for final VA worse than CF. The steep cost of investigations and treatment posed challenges for many patients in the management of ON.

CONCLUSION

MOG-IgG-associated ON is common in India. Unfortunately, financial constraints delay the diagnosis and timely management of ON, adversely affecting the outcome.

Clinical features and prognosis of Tibetan patients with neuromyelitis optica spectrum disorder are different from those of Han Chinese patients

We compared the prognosis of Tibetan and Han Chinese patients with neuromyelitis optica spectrum disorder (NMOSD). The Expanded Disability Status Scale (EDSS) score at each attack, response to immunosuppressive therapy, risk of first relapse, severe attack, visual disability, motor disability, and total risk of disability were compared between Tibetan and Han Chinese patients. Tibetan patients showed higher EDSS during acute attacks. Annualized relapse rate did not differ between groups. Risk of severe attack, visual disability, and total risk of disability were higher in Tibetan patients. Tibetan patients with NMOSD have a higher risk of poor prognosis than Han Chinese patients.

A Rare Case of Longitudinally Extensive Transverse Myelitis Following Febrile Illness: A Case Report

Longitudinally extensive transverse myelitis (LETM) is a rapidly progressing demyelinating disease affecting the spinal cord over three or more vertebral segments. Most causes are idiopathic, while others include infections, autoimmune causes, central nervous system demyelinating diseases, and post vaccination. Here, we report a 37-year-old male who presented with a fever for six days with no source of infection and complained of pain and weakness in the bilateral lower limbs eight hours after admission. Though the neurological examination of the lower limbs was normal at that time, reduced power was detected 16 hours later, with loss of proprioception and sensation of pain with a sensory level at T4 vertebrae. Then, the patient became unable to vocalize, and the chest X-ray showed an elevated left hemidiaphragm. Thirty hours after admission, the patient went into type 2 respiratory arrest and was intubated. The magnetic resonance imaging (MRI) showed a longitudinally extensive transverse myelitis extending from the C2 vertebrae to the conus medullaris. Febrile illness is common in the medical setting in Sri Lanka, but its association with LETM is unusual. Since LETM is very rare and is a rapidly progressive disease, a high degree of clinical suspicion is crucial for early diagnosis and the initiation of treatment. This case underscores the importance of early diagnosis, which would require timely MRI, and prompt treatment with intravenous (IV) glucocorticoids or plasma exchange to reduce morbidity and mortality.

Immunological regulation and the role of autophagy in preeclampsia

Autophagy is a bulk degradation system that maintains cellular homeostasis by producing energy and/or recycling excess proteins. During early placentation, extravillous trophoblasts invade the decidua and uterine myometrium, facing maternal immune cells, which participate in the immune suppression of paternal and fetal antigens. Regulatory T cells will likely increase in response to a specific antigen before and during early pregnancy. Insufficient expansion of antigen-specific Treg cells, which possess the same T cell receptor, is associated with the pathophysiology of preeclampsia, suggesting sterile systemic inflammation. Autophagy is involved in reducing inflammation through the degradation of inflammasomes and in the differentiation and function of regulatory T cells. Autophagy dysregulation induces protein aggregation in trophoblasts, resulting in placental dysfunction. In this review, we discuss the role of regulatory T cells in normal pregnancies. In addition, we discuss the association between autophagy and regulatory T cells in the development of preeclampsia based on reports on the role of autophagy in autoimmune diseases.

Star power: harnessing the reactive astrocyte response to promote remyelination in multiple sclerosis

Astrocytes are indispensable for central nervous system development and homeostasis. In response to injury and disease, astrocytes are integral to the immunological- and the, albeit limited, repair response. In this review, we will examine some of the functions reactive astrocytes play in the context of multiple sclerosis and related animal models. We will consider the heterogeneity or plasticity of astrocytes and the mechanisms by which they promote or mitigate demyelination. Finally, we will discuss a set of biomedical strategies that can stimulate astrocytes in their promyelinating response.

A Comparative Review of Typical and Atypical Optic Neuritis: Advancements in Treatments, Diagnostics, and Prognosis

Optic neuritis (ON) is a debilitating condition that through various mechanisms, including inflammation or demyelination of the optic nerve, can result in partial or total permanent vision loss if left untreated. Accurate diagnosis and promptly initiated treatment are imperative related to the potential of permanent loss of vision if left untreated, which can lead to a significant reduction in the quality of life in affected patients. ON is subtyped as "typical" or "atypical" based on underlying causative etiology. The etiology of ON can be differentiated when appropriate diagnostic testing is performed. Using history taking, neuroimaging, and visual testing to localize the underlying pathology of ON in a time-sensitive manner is critical in mitigating these unsatisfactory outcomes. Herein, we examine the differences in presentation, pathophysiology, and treatments of typical ON causes, like multiple sclerosis (MS), and atypical causes such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) ON. The present investigation places focus on both neuroimaging and visual imaging in the differentiation of ON. Additionally, this review presents physicians with a better understanding of different presentations, treatments, and prognoses of ON.

Patterns of neuromyelitis optica spectrum disorder attacks in different age groups and sexes depending on the status of immunosuppressive therapy: A retrospective cohort study

BACKGROUND AND PURPOSE

The association between onset age and sex with relapse risk in neuromyelitis optica spectrum disorder (NMOSD) remains inconclusive. We aimed to describe the clinical features of patients with NMOSD in different age groups and sexes and to analyse relapse characteristics pre- and post-immunosuppressive therapy (IST).

METHODS

Patients with NMOSD were retrospectively reviewed from our clinical centre's database. Demographic and clinical data, attack presentation, and disease course pre- and post-IST were investigated. We also analysed the effect of onset age on the annualized relapse rate and relapse risk according to sex and IST status. Interactions on the additive scale between onset age and sex were analysed. A restricted cubic spline was used to analyse potential nonlinear correlations. Longitudinal changes in the Expanded Disability Status Scale score across NMOSD attacks were analysed using linear mixed-effect models.

RESULTS

In total, 533 patients experienced 1394 attacks pre-IST and 753 relapses post-IST. Older age at onset was correlated with more myelitis attacks but fewer optic neuritis attacks, with no sex-related differences in attack presentation. Pre-IST, relapse risk increased with age at onset in women, while a U-shaped correlation between onset age and relapse risk was found in men. Post-IST, an inverted U-shaped association between the predicted relapse risk and onset age was observed in women. Conversely, a negative correlation between the predicted relapse risk and onset age was found in men. Overall, a higher ratio of myelitis attacks was found post-IST.

CONCLUSIONS

Patients of different onset ages and sexes had different relapse patterns before and after IST.

Interactions Between Extracellular Vesicles and Autophagy in Neuroimmune Disorders

Neuroimmune disorders, such as multiple sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis, and Guillain-Barré syndrome, are characterized by the dysfunction of both the immune system and the nervous system. Increasing evidence suggests that extracellular vesicles and autophagy are closely associated with the pathogenesis of these disorders. In this review, we summarize the current understanding of the interactions between extracellular vesicles and autophagy in neuroimmune disorders and discuss their potential diagnostic and therapeutic applications. Here we highlight the need for further research to fully understand the mechanisms underlying these disorders, and to develop new diagnostic and therapeutic strategies.

APOE from patient-derived astrocytic extracellular vesicles alleviates neuromyelitis optica spectrum disorder in a mouse model

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy of the central nervous system, mediated by antibodies against aquaporin-4 water channel protein (AQP4-Abs), resulting in damage of astrocytes with subsequent demyelination and axonal damage. Extracellular communication through astrocyte-derived extracellular vesicles (ADEVs) has received growing interest in association with astrocytopathies. However, to what extent ADEVs contribute to NMOSD pathogenesis remains unclear. Here, through proteomic screening of patient-derived ADEVs, we observed an increase in apolipoprotein E (APOE)-rich ADEVs in patients with AQP4-Abs-positive NMOSD. Intracerebral injection of the APOE-mimetic peptide APOE130-149 attenuated microglial reactivity, neuroinflammation, and brain lesions in a mouse model of NMOSD. The protective effect of APOE in NMOSD pathogenesis was further established by the exacerbated lesion volume in APOE-deficient mice, which could be rescued by exogenous APOE administration. Genetic knockdown of the APOE receptor lipoprotein receptor-related protein 1 (LRP1) could block the restorative effects of APOE130-149 administration. The transfusion ADEVs derived from patients with NMOSD and healthy controls also alleviated astrocyte loss, reactive microgliosis, and demyelination in NMOSD mice. The slightly larger beneficial effect of patient-derived ADEVs as compared to ADEVs from healthy controls was further augmented in APOE-/- mice. These results indicate that APOE from astrocyte-derived extracellular vesicles could mediate disease-modifying astrocyte-microglia cross-talk in NMOSD.

Association between Sjögren syndrome, sociodemographic factors, comorbid conditions, and optic neuritis: a Taiwanese population-based study

Purpose

Our study aimed to explore the correlation between Sjögren syndrome, sociodemographic factors, comorbid conditions, and optic neuritis.

Methods

This retrospective, nationwide, population-based, matched case-control investigation involved 33,190 individuals diagnosed with optic neuritis, identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes 377.30 for optic neuritis or 377.32 for retrobulbar neuritis. Patient data were extracted from the Taiwan National Health Insurance Research Database. Demographic characteristics, the presence of Sjögren syndrome, and pre-existing comorbid conditions were analyzed using univariate logistic regression. Continuous variables were assessed with a paired t-test. Adjusted logistic regression was employed to compare the prognosis odds ratio (OR) of patients with optic neuritis to controls.

Results

After adjusting for confounding variables, individuals with Sjögren syndrome exhibited a significantly higher likelihood of developing optic neuritis compared to controls (adjusted OR, 9.79; 95% confidence interval [CI], 7.28-12.98; p < 0.0001). Other conditions associated with increased odds of optic neuritis included rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis, systemic lupus erythematosus, and granulomatous vasculitis (adjusted OR: 1.57, 95% CI: 1.33-1.86; adjusted OR: 2.02, 95% CI: 1.65-2.48; adjusted OR: 140.77, 95% CI: 35.02-565.85; adjusted OR: 2.38, 95% CI: 1.71-3.30; adjusted OR: 18.28, 95% CI: 2.21-151.45, respectively), as well as systemic infections such as human herpes viral infection and tuberculosis infection (adjusted OR: 1.50, 95% CI: 1.35-1.66; adjusted OR: 4.60, 95% CI: 3.81-5.56, respectively).

Discussion

Our findings strongly support the existence of an association between Sjögren syndrome, rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis, systemic lupus erythematosus, granulomatous vasculitis, human herpes viral infection, tuberculosis, and optic neuritis.

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

Serum Albumin Level Can Predict Immunotherapy Response of Neuromyelitis Optica Spectrum Disorders in the Acute Phase

Background

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disease of the central nervous system. However, few biomarkers have been found to predict the outcome of immunotherapy. We investigated the relationship between the serum albumin (S-Alb) and response to immunotherapy in acute NMOSD patients.

Methods

A total of 107 consecutive Chinese patients with acute NMOSD diagnosed between January 2013 and January 2022 were included in our prospective observational study. S-Alb was measured by the use of bromocresol green and immunoturbidimetric methods on admission. The immunotherapy response was assessed by the percentage change in the expanded disability status scale (EDSS) score from admission to discharge after treatment. We evaluated the association between S-Alb and immunotherapy response through multivariate logistic regression analysis.

Results

S-Alb levels were significantly lower in patients who were resistant to immunotherapy than in those who were responsive to treatment (p<0.001). S-Alb levels were positively related to a favorable response to immunotherapy (r=0.386, p<0.001). The odds ratio (95% CI) for the association between S-Alb level and response to immunotherapy was 1.27 (95% CI=1.08, 1.50; p=0.004) after adjusting for potential factors. ROC analysis showed that patients with S-Alb levels lower than 40.85 g/L were likely to be resistant to immunotherapy.

Conclusion

Our study indicated that a higher S-Alb was an independent indicator of response to immunotherapy in acute NMOSD patients.

Visualization and analysis of mapping knowledge domains for optic neuritis: a bibliometric research from 2013 to 2022

PURPOSE

To explore the global research trends, hotspots and frontiers of optic neuritis (ON) over the past decade through qualitative and quantitative analysis of bibliometrics.

METHODS

Publications on ON from 2013 to 2022 were retrieved from Web of Science Core Collection (WoSCC). VOSviewer and CiteSpace were mainly used to facilitate bibliometric analysis and visualization.

RESULTS

A total of 3027 papers were retrieved from peer-reviewed publications and the annual research output increased over time. Neurosciences neurology was the most published area. The USA was the most productive and influential country, and in the focus of international cooperation. University College London was the most productive organization and Charite Medical University of Berlin had the largest number of cooperating partners. Paul F contributed the largest number of publications and Wingerchuk DM ranked first among the co-cited authors. Multiple Sclerosis and Related Disorders was the most prolific journal publishing ON research. The most co-cited references mainly focused on the diagnostic criteria for neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). The keywords formed the following four clusters: the pathophysiology of MS-ON; the autoantibody markers and diagnostic criteria of NMOSD-ON and myelin oligodendrocyte glycoprotein associated disorder-ON (MOGAD-ON); the epidemiology and clinical characteristics of ON; and the treatment of ON.

CONCLUSION

This bibliometrics analysis showed a systematic view of the evolutionary process, research hotspots, and future directions of ON research. It can provide insights for ON research and valuable information for neuro-ophthalmologic specialists to evaluate research policies and promote international cooperation.

Peripheral memory B cells in multiple sclerosis vs. double negative B cells in neuromyelitis optica spectrum disorder: disease driving B cell subsets during CNS inflammation

B cells are fundamental players in the pathophysiology of autoimmune diseases of the central nervous system, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). A deeper understanding of disease-specific B cell functions has led to the differentiation of both diseases and the development of different treatment strategies. While NMOSD is strongly associated with pathogenic anti-AQP4 IgG antibodies and proinflammatory cytokine pathways, no valid autoantibodies have been identified in MS yet, apart from certain antigen targets that require further evaluation. Although both diseases can be effectively treated with B cell depleting therapies, there are distinct differences in the peripheral B cell subsets that influence CNS inflammation. An increased peripheral blood double negative B cells (DN B cells) and plasmablast populations has been demonstrated in NMOSD, but not consistently in MS patients. Furthermore, DN B cells are also elevated in rheumatic diseases and other autoimmune entities such as myasthenia gravis and Guillain-Barré syndrome, providing indirect evidence for a possible involvement of DN B cells in other autoantibody-mediated diseases. In MS, the peripheral memory B cell pool is affected by many treatments, providing indirect evidence for the involvement of memory B cells in MS pathophysiology. Moreover, it must be considered that an important effector function of B cells in MS may be the presentation of antigens to peripheral immune cells, including T cells, since B cells have been shown to be able to recirculate in the periphery after encountering CNS antigens. In conclusion, there are clear differences in the composition of B cell populations in MS and NMOSD and treatment strategies differ, with the exception of broad B cell depletion. This review provides a detailed overview of the role of different B cell subsets in MS and NMOSD and their implications for treatment options. Specifically targeting DN B cells and plasmablasts in NMOSD as opposed to memory B cells in MS may result in more precise B cell therapies for both diseases.

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.

Treatment of neuromyelitis optica spectrum disorder: revisiting the complement system and other aspects of pathogenesis

Neuromyelitis optica spectrum disorder (NMOSD) represents a rare neuroimmunological disease causing recurrent attacks and accumulation of permanent disability in affected patients. The discovery of the pathogenic IgG‑1 antibody targeting a water channel expressed in astrocytes, aquaporin 4, constitutes a milestone achievement. Subsequently, multiple pathophysiological aspects of this distinct disease entity have been investigated. Demyelinating lesions and axonal damage ensue from autoantibodies targeting an astroglial epitope. This conundrum has been addressed in the current disease model, where activation of the complement system as well as B cells and interleukin 6 (IL-6) emerged as key contributors. It is the aim of this review to address these factors in light of novel treatment compounds which reflect these pathophysiological concepts in aiming for attack prevention, thus reducing disease burden in patients with NMOSD.

Emerging functions and therapeutic targets of IL-38 in central nervous system diseases

Interleukin (IL)-38 is a newly discovered cytokine of the IL-1 family, which binds various receptors (i.e., IL-36R, IL-1 receptor accessory protein-like 1, and IL-1R1) in the central nervous system (CNS). The hallmark physiological function of IL-38 is competitive binding to IL-36R, as does the IL-36R antagonist. Emerging research has shown that IL-38 is abnormally expressed in the serum and brain tissue of patients with ischemic stroke (IS) and autism spectrum disorder (ASD), suggesting that IL-38 may play an important role in neurological diseases. Important advances include that IL-38 alleviates neuromyelitis optica disorder (NMOD) by inhibiting Th17 expression, improves IS by protecting against atherosclerosis via regulating immune cells and inflammation, and reduces IL-1β and CXCL8 release through inhibiting human microglial activity post-ASD. In contrast, IL-38 mRNA is markedly increased and is mainly expressed in phagocytes in spinal cord injury (SCI). IL-38 ablation attenuated SCI by reducing immune cell infiltration. However, the effect and underlying mechanism of IL-38 in CNS diseases remain inadequately characterized. In this review, we summarize the biological characteristics, pathophysiological role, and potential mechanisms of IL-38 in CNS diseases (e.g., NMOD, Alzheimer's disease, ASD, IS, TBI, and SCI), aiming to explore the therapeutic potential of IL-38 in the prevention and treatment of CNS diseases.

Susceptibility-weighted image features in AQP4-negative-NMOSD versus MS

OBJECTIVE

To characterize the susceptibility-weighted image (SWI) features including paramagnetic rim and nodular lesions with signal intensity changes and central vein sign (CVS) associated with aquaporin 4 (AQP4)-immunoglobulin G (IgG)-negative neuromyelitis optica spectrum disorder (NMOSD), and explore whether they can be used as potential imaging biomarkers for differentiating multiple sclerosis (MS) from this disorder.

METHODS

We prospectively recruited NMOSD with AQP4-IgG-negative (AQP4- NMOSD) and IgG-positive (AQP4+ NMOSD), and MS subjects from the Clinical and Imaging Patterns of Neuroinflammation Diseases in China (CLUE) project (NCT0410683) between 2019 and 2021. The SWI features including paramagnetic rim and nodular lesions with signal intensity changes and CVS were analyzed and compared among groups, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for distinguishing MS from AQP4- NMOSD.

RESULTS

We enrolled a total of 160 consecutive patients (22 AQP4- NMOSD, 65 AQP4+ NMOSD, and 73 MS). We observed paramagnetic rim lesion (0/120 lesions, 0 %) and nodular (1/120, 1 %) lesions with hypointense signals on SWI in the AQP4- NMOSD group. These characteristics were similar to those recorded from AQP4+ NMOSD patients (rim: 0/369 lesions, 0 %, P = 1.000; nodular: 10/369 lesions, 2.7 %, P = 1.000), but differed significantly from those observed in the MS group (rim: 162/1665 lesions, 9.7 %, P<0.001; nodular: 392/1665 lesions, 23.5 %, P < 0.001). AQP4- NMOSD patients had fewer average CVS+ rate (12 %) than MS patients (46 %, p<0.001), similar to AQP4+ NMOSD (13 %, p = 1.000). The SWI imaging features denoting lesions with paramagnetic rim or nodular hypointense SWI signals showed 90.4 % sensitivity, 95.5 % specificity, 98.5 % PPV, and 75 % NPV, and the criteria with≥3 CVS lesions showed sensitivity of 91.8 %, specificity of 90.9 %%, PPV of 97.1 %, and NPV of 76.9 % in distinguishing MS from AQP4- NMOSD.

DISCUSSION

The SWI imaging features including lesions with paramagnetic rim or nodular hypointense SWI signals and 3 CVS lesions carries useful information in distinguishing MS from AQP4- NMOSD.

Advances in the long-term treatment of neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune neuroinflammatory disorder with a prevalence of 1-5/100,000 globally, characterized by attacks of the central nervous system including but not limited to optic neuritis, transverse myelitis and brainstem lesions, including area postrema lesions. These autoimmune attacks can lead to irreversible damage if left untreated, therefore strategies have been developed to prevent relapses. Initial off-label treatments have achieved variable levels of success in relapse prevention, but improved relapse prevention and quality of life remain a goal in the field. A better understanding of the underlying pathophysiology of NMOSD over the last 10 years has led to newer, more specific approaches in treatment, culminating in the first FDA approved treatments in the disease. In this review, we will discuss the seminal trials of PREVENT or Eculizumab in the treatment of aquaporin-4 (AQP4)-IgG positive NMOSD, N-Momentum or Inebilizumab in the study of NMOSD (both AQP4-IgG positive and negative) and SAkura Sky and SAkuraStar which studied satralizumab in AQP4-IgG seropositive and seronegative NMOSD patients. We will also discuss the extension trials of each of these medications and what lead to their approval in AQP4-IgG seropositive NMOSD patients. We will then examine treatments in the pipeline for adult and pediatric NMOSD patients and conclude with discussions on treatment considerations in pregnant patients and how to approach treatment of NMOSD patients during COVID.

Early involvement of peripherally derived monocytes in inflammation in an NMO-like mouse model

Neuromyelitis optica (NMO) is an autoimmune inflammatory disease that primarily affects the optic nerve and spinal cord within the central nervous system (CNS). Acute astrocyte injury caused by autoantibodies against aquaporin 4 (NMO-IgG) is a well-established key factor in the pathogenesis, ultimately leading to neuronal damage and patient disability. In addition to these humoral immune processes, numerous innate immune cells were found in the acute lesions of NMO patients. However, the origin and function of these innate immune cells remain unclear in NMO pathogenesis. Therefore, this study aims to analyze the origin and functions of these innate immune cells in an NMO-like mouse model and evaluate their role in the pathophysiology of NMO. The expression of Tmem119 on Iba1 + cells in brain tissue disappeared immediately after the injection of NMO-IgG + human complement mixture, while the expression of P2ry12 remained well-maintained at 1 day after injection. Based on these observations, it was demonstrated that monocytes infiltrate the brain during the early stages of the pathological process and are closely associated with the inflammatory response through the expression of the proinflammatory cytokine IL-1β. Understanding the variations in the expression patterns of P2ry12, Tmem119, and other markers could be helpful in distinguishing between these cell types and further analyzing their functions. Therefore, this research may contribute to a better understanding of the mechanisms and potential treatments for NMO.

Relapses and Serious Infections in Patients with Neuromyelitis Optica Spectrum Disorder Treated with Rituximab: A Swedish Single-Center Study

Neuromyelitis optica spectrum disorder (NMOSD) is a rare immune-mediated relapsing-remitting disease of the central nervous system. The usage of rituximab, as relapse-preventive therapy, in NMOSD is common. We performed a single-center retrospective cohort study to assess the risk of relapses and severe infectious events (SIEs) in rituximab-treated NMOSD patients. This study included 24 aquaporin-4 IgG+ (AQP4+), 8 myelin-oligodendrocyte-protein IgG+ (MOG+), and 10 double-seronegative NMOSD patients. Relapses were observed in 50% of all patients during a mean treatment time of 4.0 (range: 0.5-8.25) years. The incidence risk ratio (IRR) of relapse was three times higher in MOG+ compared to AQP4+ patients (IRR: 3.0, 95% confidence interval (CI); 1.2-7.7). SIEs occurred in 40% of all patients during follow-up. AQP4+ patients conferred an increased risk of SIEs compared to MOG+ patients (IRR; 5.3, 95% CI; 1.2-24.3). Incomplete CD19+ B-lymphocyte suppression was not correlated with relapse risk (hazard ratio; 1.9, 95% CI; 0.7-5.2), and there was no correlation between IgG-levels and SIE risk (odds ratio; 2.0, 95% CI; 0.8-4.8). In conclusion, considerable risks of both relapses and SIEs were observed in NMOSD patients exposed to rituximab, which underlines the need for close clinical vigilance of disease activity and infections during treatment.

Risk factors and prognosis of orotracheal intubation in aquaporin-4-IgG neuromyelitis optica spectrum disorder attacks

BACKGROUND

Aquaporin-4 immunoglobulin G Neuro Myelitis Optica spectrum disorders attacks (NMOSD-AQP4-IgG+ attacks) can cause respiratory failure requiring orotracheal intubation (OTI), but the risk factors and outcomes of OTI during attacks remain unclear. Our primary objective was to identify the clinical and radiological risk factors for OTI in NMOSD-AQP4-IgG+ attacks. As a secondary objective, we aimed to evaluate the prognosis of OTI-attacks.

METHODS

We retrospectively analyzed NMOSD-AQP4-IgG+ attacks at the Pitié-Salpêtrière Hospital (Jan 2010-Jan 2021), excluding isolated optic neuritis. The primary outcome was the need for OTI due to neurological dysfunction an attack (OTI-attack). The secondary outcome was attack's poor recovery after 12 months, defined as a modified Rankin score (mRS) > 2 in patients with an initial mRS ≤ 2, or an increase ≥ 1 point in mRS in other patients. Analyses were performed using a binomial generalized linear mixed model, with a random intercept for the patient ID to account for within-patient correlations.

RESULTS

Seventy-three attacks in 44 patients NMOSD-AQP4-IgG+ were analyzed. Of 73 attacks, 8 (11%) required OTI during the attack, related to acute restrictive respiratory failure (n = 7) and/or severe swallowing disorder (n = 2). None of the OTI-attacks occurred in patients previously treated with active disease-modifying treatment (DMT), while 36 (55.4%) of the non-OTI-attacks occurred in patients who were already on active DMT. On admission, OTI-attacks were more likely to have upper limbs motor paresis of (75.0% versus 29.2%, p = 0.366) and dyspnea (3 [50.0%] versus 4 [6.6%], p = 0.002) compared to non-OTI-attacks. MRI analysis showed that OTI-attacks had edematous lesions in the cervical spinal cord, mainly at levels C1 (75% versus 0% in non-OTI-attacks), C2 (75% versus 1.9%), C3 (62.5% versus 1.9%), and C4 and C5 levels (50% versus to 3.9%). One OTI-attack resulted in the death of one patient. Five patients with OTI-attack had mRS ≤ 2 one year after OTI-attack. Two (25%) OTI-attacks had poor recovery compared to 15 (24.2%) non-OTI-attacks (p = 0.468).

CONCLUSION

OTI-attacks occurred in untreated NMOSD-AQP4-IgG+ patients and were associated with edematous upper cervical lesions. The prognosis of these attacks may be favorable, and warrant maximal medical and supportive treatment. Trial registration This was a retrospective observational monocentric cohort study nested in the NOMADMUS cohort (ClinicalTrials.gov Identifier: NCT02850705).