Serologic diagnosis of NMO: a multicenter comparison of aquaporin-4-IgG assays

A quantitative method for aquaporin-1 protein using magnetic preconcentration and probe-based immunoassay coupling to inductively coupled plasma mass spectrometry in urine analysis

BACKGROUND

Aquaporin-1 (AQP1) protein plays a crucial role in intracellular and extracellular water homeostasis and fluid transport in organs and tissues associated with diverse life activities and is extremely abundant in the kidney. Accurate detection of AQP1 in urine can be applied as screening of early-stage disease. Application of magnetic preconcentration and probe-based signal amplification strategy coupling to inductively coupled plasma mass spectrometry (ICP-MS) is a more accurate, sensitive and specific detection method for AQP1 in complex biological samples compared to conventional methods.

RESULTS

We described an element-labelling strategy based on magnetic preconcentration and probe-based immunoassay coupling to ICP-MS detection. The magnetic beads (MBs) modified with epoxy groups were capable of enriching AQP1 proteins and separating them from complex matrices. The probe constructed by conjugating anti-AQP1 antibody molecules on the surface of gold nanoparticles could specifically recognize AQP1 proteins attached on MBs and be analyzed by ICP-MS. The concentration of AQP1 protein could be precisely quantified and amplified by 14,000 times through the corresponding signal of Au atoms. This assay for AQP1 protein quantification achieved a detection limit down to 0.023 ng mL-1, a broad linear calibration curve between 0.3 ng mL-1 and 30 ng mL-1, as well as outstanding specificity.

SIGNIFICANCE

The proposed method was successfully applied to detect AQP1 protein in human urine samples, showing the potential for its applications concerning accurate AQP1 quantification. It can also screen a wide range of proteins provided the antibodies specific to these target proteins are available.

Recent advances in the diagnosis and management of neuropsychiatric lupus

Neuropsychiatric manifestations of systemic lupus erythematosus (SLE) are common and frequently associated with a substantial negative impact on health outcomes. The pathogenesis of neuropsychiatric SLE (NPSLE) remains largely unknown, but a single pathogenic mechanism is unlikely to be responsible for the heterogeneous array of clinical manifestations, and a combination of inflammatory and ischaemic mechanistic pathways have been implicated. Currently, valid and reliable biomarkers for the diagnosis of NPSLE are lacking, and differentiating NPSLE from nervous system dysfunction not caused by SLE remains a major challenge for clinicians. However, correct attribution is essential to ensure timely institution of appropriate treatment. In the absence of randomized clinical trials on NPSLE, current treatment strategies are derived from clinical experience with different therapeutic modalities and their efficacy in the management of other manifestations of SLE or of neuropsychiatric disease in non-SLE populations. This Review describes recent advances in the understanding of NPSLE that can inform diagnosis and management, as well as unanswered questions that necessitate further research.

Update on aquaporin-4 antibody detection: the early diagnosis of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune-mediated primary inflammatory myelinopathy of the central nervous system that primarily affects the optic nerve and spinal cord. The aquaporin 4 antibody (AQP4-Ab) is a specific autoantibody marker for NMOSD. Most patients with NMOSD are seropositive for AQP4-Ab, thus aiding physicians in identifying ways to treat NMOSD. AQP4-Ab has been tested in many clinical and laboratory studies, demonstrating effectiveness in diagnosing NMOSD. Recently, novel assays have been developed for the rapid and accurate detection of AQP4-Ab, providing further guidance for the diagnosis and treatment of NMOSD. This article summarizes the importance of rapid and accurate diagnosis for treating NMOSD based on a review of the latest relevant literature. We discussed current challenges and methods for improvement to offer new ideas for exploring rapid and accurate AQP4-Ab detection methods, aiming for early diagnosis of NMOSD.

Patterns of cerebral damage in multiple sclerosis and aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders-major differences revealed by non-conventional imaging

Multiple sclerosis and aquaporin-4 antibody neuromyelitis optica spectrum disorders are distinct autoimmune CNS disorders with overlapping clinical features but differing pathology. Multiple sclerosis is primarily a demyelinating disease with the presence of widespread axonal damage, while neuromyelitis optica spectrum disorders is characterized by astrocyte injury with secondary demyelination. Diagnosis is typically based on lesion characteristics observed on standard MRI imaging and antibody testing but can be challenging in patients with in-between clinical presentations. Non-conventional MRI techniques can provide valuable diagnostic information by measuring disease processes at the microstructural level. We used non-conventional MRI to measure markers of axonal loss in specific white matter tracts in multiple sclerosis and neuromyelitis optica spectrum disorders, depending on their relationship with focal lesions. Patients with relapsing-remitting multiple sclerosis (n = 20), aquaporin-4 antibody-associated neuromyelitis optica spectrum disorders (n = 20) and healthy controls (n = 20) underwent a 3T brain MRI, including T1-, T2- and diffusion-weighted sequences, quantitative susceptibility mapping and phase-sensitive inversion recovery sequence. Tractometry was used to differentiate tract fibres traversing through white matter lesions from those that did not. Neurite density index was assessed using neurite orientation dispersion and density imaging model. Cortical damage was evaluated using T1 relaxation rates. Cortical lesions and paramagnetic rim lesions were identified using phase-sensitive inversion recovery and quantitative susceptibility mapping. In tracts traversing lesions, only one out of 50 tracts showed a decreased neurite density index in multiple sclerosis compared with neuromyelitis optica spectrum disorders. Among 50 tracts not traversing lesions, six showed reduced neurite density in multiple sclerosis (including three in the cerebellum and brainstem) compared to neuromyelitis optica spectrum disorders. In multiple sclerosis, reduced neurite density was found in the majority of fibres traversing (40/50) and not traversing (37/50) white matter lesions when compared to healthy controls. A negative correlation between neurite density in lesion-free fibres and cortical lesions, but not paramagnetic rim lesions, was observed in multiple sclerosis (39/50 tracts). In neuromyelitis optica spectrum disorders compared to healthy controls, decreased neurite density was observed in a subset of fibres traversing white matter lesions, but not in lesion-free fibres. In conclusion, we identified significant differences between multiple sclerosis and neuromyelitis optica spectrum disorders corresponding to their distinct pathologies. Specifically, in multiple sclerosis, neurite density reduction was widespread across fibres, regardless of their relationship to white matter lesions, while in neuromyelitis optica spectrum disorders, this reduction was limited to fibres passing through white matter lesions. Further studies are needed to evaluate the discriminatory potential of neurite density measures in white matter tracts for differentiating multiple sclerosis from neuromyelitis optica spectrum disorders.

Autoimmune Encephalitis

OBJECTIVE

This article focuses on the clinical features and diagnostic evaluations that accurately identify patients with ever-expanding forms of antibody-defined encephalitis. Forms of autoimmune encephalitis are more prevalent than infectious encephalitis and represent treatable neurologic syndromes for which early immunotherapies lead to the best outcomes.

LATEST DEVELOPMENTS

A clinically driven approach to identifying many autoimmune encephalitis syndromes is feasible, given the typically distinctive features associated with each antibody. Patient demographics alongside the presence and nature of seizures, cognitive impairment, psychiatric disturbances, movement disorders, and peripheral features provide a valuable set of clinical tools to guide the detection and interpretation of highly specific antibodies. In turn, these clinical features in combination with serologic findings and selective paraclinical testing, direct the rationale for the administration of immunotherapies. Observational studies provide the mainstay of evidence guiding first- and second-line immunotherapy administration in autoimmune encephalitis and, whereas these typically result in some clinical improvements, almost all patients have residual neuropsychiatric deficits, and many experience clinical relapses. An improved pathophysiologic understanding and ongoing clinical trials can help to address these unmet medical needs.

ESSENTIAL POINTS

Antibodies against central nervous system proteins characterize various autoimmune encephalitis syndromes. The most common targets include leucine-rich glioma inactivated protein 1 (LGI1), N-methyl-d-aspartate (NMDA) receptors, contactin-associated proteinlike 2 (CASPR2), and glutamic acid decarboxylase 65 (GAD65). Each antibody-associated autoimmune encephalitis typically presents with a recognizable blend of clinical and investigation features, which help differentiate each from alternative diagnoses. The rapid expansion of recognized antibodies and some clinical overlaps support panel-based antibody testing. The clinical-serologic picture guides the immunotherapy regime and offers valuable prognostic information. Patient care should be delivered in conjunction with autoimmune encephalitis experts.

NMOSD and MOGAD

OBJECTIVE

This article reviews the clinical features, MRI characteristics, diagnosis, and treatment of aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). The main differences between these disorders and multiple sclerosis (MS), the most common demyelinating disease of the central nervous system (CNS), are also highlighted.

LATEST DEVELOPMENTS

The past 20 years have seen important advances in understanding rare demyelinating CNS disorders associated with AQP4 IgG and myelin oligodendrocyte glycoprotein (MOG) IgG. The rapidly expanding repertoire of immunosuppressive agents approved for the treatment of AQP4-NMOSD and emerging as potentially beneficial in MOGAD mandates prompt recognition of these diseases. Most of the recent literature has focused on the identification of clinical and MRI features that help distinguish these diseases from each other and MS, simultaneously highlighting major diagnostic pitfalls that may lead to misdiagnosis. An awareness of the limitations of currently available assays for AQP4 IgG and MOG IgG detection is fundamental for identifying rare false antibody positivity and avoiding inappropriate treatments. For this purpose, diagnostic criteria have been created to help the clinician interpret antibody testing results and recognize the clinical and MRI phenotypes associated with AQP4-NMOSD and MOGAD.

ESSENTIAL POINTS

An awareness of the specific clinical and MRI features associated with AQP4-NMOSD and MOGAD and the limitations of currently available antibody testing assays is crucial for a correct diagnosis and differentiation from MS. The growing availability of effective treatment options will lead to personalized therapies and improved outcomes.

Characterizing mortality in patients with AQP4-Ab+ neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder is an autoimmune disease, causing severe disability due to relapses, but recent mortality data are limited. Among 396 patients seropositive for anti-aquaporin-4 antibody from 2014 to 2020 in the United Kingdom, 39 deaths occurred: 19 (48.7%) were unrelated to disease; 14 (35.9%) were severe disability- or relapse-related; and 4 (10.3%) were attributed to malignancy/infection. Mean annual mortality was 1.92% versus 0.63% in the matched population. The standardized mortality ratio was 3.04 (95% confidence interval 1.67-5.30) with 1.29% excess mortality per year in patients. Median Expanded Disability Status Scale before death was 7.0. Results highlight the importance of preventing relapses that drive disability.

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.

Cell-based vs enzyme-linked immunosorbent assay for detection of anti-Tribbles homolog 2 autoantibodies in Chinese patients with narcolepsy

STUDY OBJECTIVES

Narcolepsy type 1 is attributed to a deficiency in cerebrospinal fluid orexin and is considered linked to autoimmunity. The levels of anti-Tribbles homolog 2 (TRIB2) autoantibodies are elevated in the sera of some patients with narcolepsy with cataplexy. Additionally, injecting mice with serum immunoglobulin from patients with narcolepsy with positive anti-TRIB2 antibodies can induce hypothalamic neuron loss and alterations in sleep patterns. Consequently, we hypothesized the existence of a potential association between anti-TRIB2 antibodies and narcolepsy. To test this possibility, we used cell-based assays (CBAs) and enzyme-linked immunosorbent assays (ELISAs) to detect the presence of anti-TRIB2 antibodies in Chinese patients with narcolepsy.

METHODS

We included 68 patients with narcolepsy type 1, 39 patients with other central disorders of hypersomnolence, and 43 healthy controls. A CBA and a conventional ELISA were used to detect anti-TRIB2 antibody levels in patients' sera.

RESULTS

CBA was used to detect serum anti-TRIB2 antibodies in Chinese patients with narcolepsy, and the results were negative. However, when the ELISA was used, only 2 patients with narcolepsy type 1 had TRIB2 antibody titers higher than the mean titer plus 2 standard deviations of the healthy controls.

CONCLUSIONS

In our study, ELISA identified TRIB2 autoantibodies in sera of patients with narcolepsy where CBA failed to demonstrate them. Contrary to our hypothesis, this intriguing finding deserves further research to elucidate the potential association between TRIB2 and narcolepsy type 1. Exploring the implications of TRIB2 autoantibodies in narcolepsy and disparate outcomes between ELISA and CBA could provide crucial insights.

CITATION

Zhong X, Yuan Y, Zhan Q, et al. Cell-based vs enzyme-linked immunosorbent assay for detection of anti-Tribbles homolog 2 autoantibodies in Chinese patients with narcolepsy. J Clin Sleep Med. 2024;20(6):941-946.

Radiologic Lag and Brain MRI Lesion Dynamics During Attacks in MOG Antibody-Associated Disease

BACKGROUND AND OBJECTIVES

Knowledge of the evolution of CNS demyelinating lesions within attacks could assist diagnosis. We evaluated intra-attack lesion dynamics in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) vs multiple sclerosis (MS) and aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (AQP4+NMOSD).

METHODS

This retrospective observational multicenter study included consecutive patients from Mayo Clinic (USA) and Great Ormond Street Hospital for Children (UK). Inclusion criteria were as follows: (1) MOGAD, MS, or AQP4+NMOSD diagnosis; (2) availability of ≥2 brain MRIs (within 30 days of attack onset); and (3) brain involvement (i.e., ≥1 T2 lesion) on ≥1 brain MRI. The initial and subsequent brain MRIs within a single attack were evaluated for the following: new T2 lesions(s); resolved T2 lesion(s); both; or no change. This was compared between MOGAD, MS, and AQP4+NMOSD attacks. We used the Mann-Whitney U test and χ2/Fisher exact test for statistical analysis.

RESULTS

Our cohort included 55 patients with MOGAD (median age, 14 years; interquartile range [IQR] 5-34; female sex, 29 [53%]) for a total of 58 attacks. The comparison groups included 38 patients with MS, and 19 with AQP4+NMOSD. In MOGAD, the initial brain MRI (median of 5 days from onset [IQR 3-9]) was normal in 6/58 (10%) attacks despite cerebral symptoms (i.e., radiologic lag). The commonest reason for repeat MRI was clinical worsening or no improvement (33/56 [59%] attacks with details available). When compared with the first MRI, the second intra-attack MRI (median of 8 days from initial scan [IQR 5-13]) showed the following: new T2 lesion(s) 27/58 (47%); stability 24/58 (41%); resolution of T2 lesion(s) 4/58 (7%); or both new and resolved T2 lesions 3/58 (5%). Findings were similar between children and adults. Steroid treatment was associated with resolution of ≥1 T2 lesion (6/28 [21%] vs 1/30 [3%], p = 0.048) and reduced the likelihood of new T2 lesions (9/28 vs 18/30, p = 0.03). Intra-attack MRI changes favored MOGAD (34/58 [59%]) over MS (10/38 [26%], p = 0.002) and AQP4+NMOSD (4/19 [21%], p = 0.007). Resolution of ≥1 T2 lesions was exclusive to MOGAD (7/58 [12%]).

DISCUSSION

Radiologic lag is common within MOGAD attacks. Dynamic imaging with frequent appearance and occasional disappearance of lesions within a single attack suggest MOGAD diagnosis over MS and AQP4+NMOSD. These findings have implications for clinical practice, clinical trial attack adjudication, and understanding of MOGAD pathogenesis.

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.

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.

Updates in NMOSD and MOGAD Diagnosis and Treatment: A Tale of Two Central Nervous System Autoimmune Inflammatory Disorders

Aquaporin-4-IgG positive neuromyelitis optica spectrum disorder (AQP4+NMOSD) and myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are antibody-associated diseases targeting astrocytes and oligodendrocytes, respectively. Their recognition as distinct entities has led to each having its own diagnostic criteria that require a combination of clinical, serologic, and MRI features. The therapeutic approach to acute attacks in AQP4+NMOSD and MOGAD is similar. There is now class 1 evidence to support attack-prevention medications for AQP4+NMOSD. MOGAD lacks proven treatments although clinical trials are now underway. In this review, we will outline similarities and differences between AQP4+NMOSD and MOGAD in terms of diagnosis and treatment.

Prevalence, Demographic, and Clinical Factors Associated With Cognitive Dysfunction in Patients With Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVES

Neuromyelitis optica spectrum disorder (NMOSD) is a chronic CNS demyelinating autoimmune disorder targeting the astrocyte antigen aquaporin-4 (AQP4), typically presenting with optic neuritis, transverse myelitis, and brain syndromes. Cognitive dysfunction (CD) in NMOSD is under-recognized and poorly understood. The purpose of this study was to evaluate the prevalence and clinical variables associated with CD in NMOSD.

METHODS

This observational retrospective study with longitudinal follow-up describes a clinical cohort seen in the Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD. Serial Montreal Cognitive Assessments (MoCAs) were performed upon enrollment and at 6-month intervals to evaluate longitudinal cognitive function relative to demographic and disease-related factors. We used 2-tailed t test, analysis of variance, the χ2 test, linear regression for univariable and adjusted analyses and simultaneous linear regression and mixed-effects model for multivariable analyses.

RESULTS

Thirty-four percent (75/219) of patients met criteria for CD (MoCA <26); 29% (64/219) showed mild dysfunction (MoCA 20-26/30), and 5% (11/219) showed moderate (MoCA <20/30) dysfunction. Patients with less neurologic disability and lower pain scores had higher MoCA scores (95% CI 0.24-0.65 and 95% CI 0.09-0.42, respectively). Patients with at least high school education scored higher on the MoCA (95% CI 2.2-5). When comparing patients dichotomized for CD, patients never on rituximab scored higher than patients only treated with rituximab (p < 0.029). There was no significant association between annualized relapse rate, age, sex, disease duration, AQP4 serostatus or brain lesions, and CD. CD was more pronounced among Black than White patients (95% CI -2.7 to -0.7). Multivariable analysis of serial MoCA did not indicate change (p = 0.715). Descriptive analysis of serial MoCA showed 30% (45/150) of patients with worsening MoCA performance had impaired language and verbal recall.

DISCUSSION

To our knowledge, this is the largest study of diverse cohort to investigate CD in patients with NMOSD. Our findings demonstrate 34% of patients with NMOSD experience mild-to-moderate CD, while 30% of patients demonstrated decline on serial testing. The substantial prevalence of CD in this pilot report highlights the need for improved and validated screening tools and comprehensive measures to investigate CD in NMOSD.

[The diagnostic effectiveness of criteria for neuromyelitis optica spectrum disorders in the Russian clinical practice]

OBJECTIVE

To compare the diagnostic criteria of 2006 (DC 2006) and 2015 (DC 2015) in the Russian population of patients with suspected neuromyelitis optica spectrum disorders (NMOSD), with the calculation of their sensitivity, specificity, accuracy and predictive value.

MATERIAL AND METHODS

We reviewed medical records of suspected NMOSD patients who were therefore examined for the presence of serum autoantibodies targeting the aquaporin-4 water channel protein (AQP4-IgG) in 6 specialized Russian (Nizhny Novgorod and Moscow) medical centers. One hundred patients (78 female), aged 17 to 74 years (mean 38.1±13.3 years), were included. The follow-up period ranged from 4 to 108 months (mean 59.7±31.6 months).

RESULTS

During the follow-up the diagnosis of NMOSD was confirmed in 32 people, and 68 patients had diagnoses different from NMOSD. At the disease onset, 68.8% of patients were seropositive for AQP4-IgG. The mean time for confirming NMOSD diagnosis was 15.2±14.2 months. At the disease onset, 36% of patients fulfilled the DC 2015, the diagnosis was subsequently confirmed in 77.8% out of them. 26% of the patients fulfilled the DC 2006, the diagnosis was subsequently confirmed in 84.6% out of them. The sensitivity of DC 2006/DC 2015 was 69%/88%, specificity 94%/88%, accuracy 86%/88%, negative predictive value 85%/94%, positive predictive value 86%/78%.

CONCLUSION

The specificity, sensitivity and accuracy of modern diagnostic criteria for NMOSD In Russian patients is comparable to those obtained in foreign studies. DC 2015 helps to diagnose NMOSD earlier than DC 2006, but they have a lower specificity.

Optimizing the diagnostic performance of neural antibody testing for paraneoplastic and autoimmune encephalitis in clinical practice

The detection of neural antibodies in patients with paraneoplastic and autoimmune encephalitis has majorly advanced the diagnosis and management of neural antibody-associated diseases. Although testing for these antibodies has historically been restricted to specialized centers, assay commercialization has made this testing available to clinical chemistry laboratories worldwide. This improved test accessibility has led to reduced turnaround time and expedited diagnosis, which are beneficial to patient care. However, as the utilization of these assays has increased, so too has the need to evaluate how they perform in the clinical setting. In this chapter, we discuss assays for neural antibody detection that are in routine use, draw attention to their limitations and provide strategies to help clinicians and laboratorians overcome them, all with the aim of optimizing neural antibody testing for paraneoplastic and autoimmune encephalitis in clinical practice.

Pediatric inflammatory leukoencephalopathies

Acquired demyelinating syndromes (ADS) represent acute neurologic illnesses characterized by deficits persisting for at least 24hours and involving the optic nerve, brain, or spinal cord, associated with regional areas of increased signal on T2-weighted images. In children, ADS may occur as a monophasic illness or as a relapsing condition, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). Almost all young people with MS have a relapsing-remitting course with clinical relapses. Important strides have been made in delineating MS from other ADS subtypes. Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and aquaporin 4-antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) were once considered variants of MS; however, studies in the last decade have established that these are in fact distinct entities. Although there are clinical phenotypic overlaps between MOGAD, AQP4-NMOSD, and MS, cumulative biologic, clinical, and pathologic evidence allows discrimination between these conditions. There has been a rapid increase in the number of available disease-modifying therapies for MS and novel treatment strategies are starting to appear for both MOGAD and AQP4-NMOSD. Importantly, there are a number of both inflammatory and noninflammatory mimics of ADS in children with implications of management for these patients in terms of treatment.

AQUAPORIN-4 (AQP-4) IMMUNOGLOBULIN G SEROPOSITIVE NEUROMYELITIS OPTICA: A REVIEW AND CASE REPORT

Background

Neuromyelitis optica spectrum disorder (NMOSD) is a relatively new terminology composed to encompass patients with neuromyelitis optica (NMO) and related immunological conditions. The diagnosis of this condition requires a seropositive aquaporin-4 immunoglobulin G (AQP-4 IgG), the presence of at least one core clinical characteristic and the exclusion of alternative diagnoses. Very few cases have been reported in sub-Saharan Africa.

Objective

The aim of this article is to report a classical case of NMOSD with AQP-4 IgG seropositivity and normal brain, cervical and thoracic MRI findings.

Result

We report a 25-year-old Nigerian woman who presented with recurrent and alternating weakness, pain and numbness of all limbs, associated with episodic painful left-sided tonic spasms and urinary incontinence. She had earlier had symptoms of recurrent, episodic and alternating loss of vision in both eyes, associated with ocular pain.Examination findings revealed an intact mental status, no cranial nerve deficit and no focal limb weakness. Right-sided deep tendon reflexes were exaggerated. Vital signs were within normal limits. Brain MRI, Cervical spine MRI and Thoracic spine MRI all revealed normal findings. Serum aquaporin-4 IgG assay returned positive with a titer of 1:32.She was commenced on high dose steroids and there was gradual improvement of symptoms.

Conclusion

These findings confirmed the diagnosis of neuromyelitis optica spectrum disorder, and satisfies the diagnostic criteria published in 2015 by the International Panel for NMO Diagnosis (IPND).

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Assessing the Correlation Between Visual Acuity and Critical Fusion Frequency in Acute Optic Neuritis Before and After Steroid Therapy

Background Optic nerve diseases include inflammatory optic nerve diseases such as vasculitis, metabolic optic neuropathy, ischemic optic neuropathy, and optic neuritis. In this study, patients with acute optic neuritis are classified with better and poor visual acuity based on visual acuity after one month of steroid pulse therapy. To determine prognosis, initial visual acuity and critical fusion frequency (CFF) values will be compared with those recorded one month after treatment and at the last visit. Methods Visual acuity and CFF were evaluated one month after the start of treatment in patients diagnosed with acute optic neuritis, and follow-up was available for at least three months at Hiroshima University Hospital. Results All patients received steroid pulse therapy as initial treatment. After one month of treatment, visual acuity and CFF at the last visit were significantly improved in the group with improved visual acuity compared to the group with impaired visual acuity. Conclusions Visual acuity at the initial visit did not affect treatment outcome, and final visual acuity and CFF after one month of treatment for acute optic neuritis were better in patients with better visual acuity. Therefore, visual acuity values one month after treatment initiation may affect treatment outcomes.

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.

Peptoids: Smart and Emerging Candidates for the Diagnosis of Cancer, Neurological and Autoimmune Disorders

Early detection of fatal and disabling diseases such as cancer, neurological and autoimmune dysfunctions is still desirable yet challenging to improve quality of life and longevity. Peptoids (N-substituted glycine oligomers) are a relatively new class of peptidomimetics, being highly versatile and capable of mimicking the architectures and the activities of the peptides but with a marked resistance to proteases and a propensity to cross the cellular membranes over the peptides themselves. For these properties, they have gained an ever greater interest in applications in bioengineering and biomedical fields. In particular, the present manuscript is to our knowledge the only review focused on peptoids for diagnostic applications and covers the last decade's literature regarding peptoids as tools for early diagnosis of pathologies with a great impact on human health and social behavior. The review indeed provides insights into the peptoid employment in targeted cancer imaging and blood-based screening of neurological and autoimmune diseases, and it aims to attract the scientific community's attention to continuing and sustaining the investigation of these peptidomimetics in the diagnosis field considering their promising peculiarities.

Patterns of Adult Neuromyelitis Optica Spectrum Disorder Patients Compared to Multiple Sclerosis: A Systematic Review and Meta-Analysis

Neuromyelitis optica spectrum disorders (NMOSDs) are central nervous system inflammatory conditions, now recognized to involve the brain, often identified by aquaporin-4 (AQP4) antibodies. We aimed to summarize the characteristics of adult NMOSD patients compared to multiple sclerosis (MS). A computerized search was conducted on MEDLINE via PubMed, Web of Science, and ProQuest using the relevant keywords. Three independent reviewers performed two-stage screening and data extraction. The Review Manager 5.4 program (Cochrane Collaboration, Windows, London, UK) was used for the analysis. The Joanna Briggs Institute (JIB) tool was used for the quality of included studies. Twenty-three articles were included. NMOSD patients were associated with older age at presentation and higher Expanded Disability Status Scale (MD = 3.88, 95% CI: 1.80 to 5.97, P = 0.0003) and (MD = 1.15, 95% CI: 0.58 to 1.72, P < 0.0001), respectively. The risk of NMOSD in females was significantly higher than MS (OR = 2.21, 95% CI: 1.41 to 3.46, P = 0.0005). Patients with NMOSD were associated with a lower risk of extrapyramidal symptoms (OR = 0.26, 95% CI: 0.11 to 0.60, P < 0.01), brainstem involvement symptoms (OR = 0.32, 95% CI: 0.16 to 0.64, P < 0.01), and developing brain lesions compared to MS (OR = 0.08, 95% CI: 0.03 to 0.18, P < 0.00001). The current evidence suggests that both NMOSD and MS have different demographic, clinical, and lesion characteristics. There is a need for additional validation of the identified differences compared with MS due to the lack of long-term systematic imaging investigations in NMOSD.

Rapid Immunodot AQP4 Assay for Neuromyelitis Optica Spectrum Disorder

Importance

Immunoglobulin G autoantibodies for aquaporin 4 (AQP4-IgG) serve as diagnostic biomarkers for neuromyelitis optica spectrum disorder (NMOSD), and the most sensitive and specific laboratory tests for their detection are cell-based assays (CBAs). Nevertheless, the limited availability of special instruments limits the widespread use of CBAs in routine laboratories.

Objective

To validate an enzyme immunodot assay for simple and rapid detection of AQP4-IgG.

Design, Setting, and Participants

This multicenter case-control study, conducted from May 2020 to February 2023, involved 4 medical centers (3 in China and 1 in Korea). The study included patients with AQP4-IgG-positive NMOSD, patients with other immune-related diseases, and healthy control individuals. Participants were excluded if they did not agree to participate or if their serum sample had turbidity.

Exposures

Serum AQP4 antibodies measured with immunodot assay.

Main Outcomes and Measures

The main outcome was performance of the immunodot assay compared with the gold standard CBA for detecting AQP4-IgG. To examine generalizability, cross-validation in Korea and at a second site in China, validation of patients with other immune-related diseases, and follow-up validation of the original cohort were performed.

Results

A total of 836 serum samples were collected; 400 were included in the diagnostic study and 436 in the validation sets. In a head-to-head diagnostic study involving 200 patients with NMOSD with AQP4-IgG (mean [SD] age, 43.1 [13.5] years; 188 [94%] female) and 200 healthy controls, use of an immunodot assay demonstrated antibody detection performance comparable to that of the gold standard (κ = 98.0%). The validation sets included 47 patients with NMOSD and 26 patients with other autoimmune diseases from Korea, 31 patients with NMOSD at a second site in China, 275 patients with other diseases, and 57 patients with NMOSD at follow-up. In the validation study, of 436 cases, 2 (<1%) were false positive and none were false negative. The CBA identified 332 AQP4-IgG-positive samples and 504 negative samples (200 [40%] in controls and 304 [60%] in patients with other diseases); 2 of the positive cases (<1%) were false negative and 4 of the negative cases (<1%) were false positive. The overall sensitivity of the immunodot assay was 99.4% (95% CI, 97.8%-99.9%), and the specificity was 99.2% (95% CI, 98.0%-99.8%).

Conclusions and Relevance

This case-control study found that the immunodot assay was comparable to CBA for detecting AQP4-IgG. With its time- and cost-efficient characteristics, the immunodot assay may be a practical option for AQP4-IgG detection.

An update on optic neuritis

Optic neuritis (ON) is the most common cause of subacute optic neuropathy in young adults. Although most cases of optic neuritis (ON) are classified as typical, meaning idiopathic or associated with multiple sclerosis, there is a growing understanding of atypical forms of optic neuritis such as antibody mediated aquaporin-4 (AQP4)-IgG neuromyelitis optica spectrum disorder (NMOSD) and the recently described entity, myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). Differentiating typical ON from atypical ON is important because they have different prognoses and treatments. Findings of atypical ON, including severe vision loss with poor recovery with steroids or steroid dependence, prominent optic disc edema, bilateral vision loss, and childhood or late adult onset, should prompt serologic testing for AQP4-IgG and MOG-IgG. Although the traditional division of typical and atypical ON can be helpful, it should be noted that there can be severe presentations of otherwise typical ON and mild presentations of atypical ON that blur these traditional lines. Rare causes of autoimmune optic neuropathies, such as glial fibrillary acidic protein (GFAP) and collapsin response-mediator protein 5 (CRMP5) autoimmunity also should be considered in patients with bilateral painless optic neuropathy associated with optic disc edema, especially if there are other accompanying suggestive neurologic symptoms/signs. Typical ON usually recovers well without treatment, though recovery may be expedited by steroids. Atypical ON is usually treated with intravenous steroids, and some forms, such as NMOSD, often require plasma exchange for acute attacks and long-term immunosuppressive therapy to prevent relapses. Since treatment is tailored to the cause of the ON, elucidating the etiology of the ON is of the utmost importance.

Defining the natural history of tumefactive demyelination: A retrospective cohort of 257 patients

OBJECTIVE

To describe demographic, clinical, and radiographic features of tumefactive demyelination (TD) and identify factors associated with severe attacks and poor outcomes.

METHODS

Retrospective review of TD cases seen at Mayo Clinic, 1990-2021.

RESULTS

Of 257 patients with TD, 183/257 (71%) fulfilled the 2017 multiple sclerosis (MS) McDonald criteria at the last follow-up, 12/257 (5%) had myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), 0 had aquaporin-4-IgG seropositive neuromyelitis optic spectrum disorders (AQP4+ NMOSD), and 62/257 (24%) were cryptogenic. Onset before age 18 was present in 18/257 (7%). Female to male ratio was 1.3:1. Cerebrospinal fluid oligoclonal (CSF) bands were present in 95/153 (62%). TD was the first demyelinating attack in 176/257 (69%). At presentation, 59/126 (47%) fulfilled Barkhof criteria for dissemination in space, 59/100 (59%) had apparent diffusion coefficient (ADC) restriction, and 57/126 (45%) had mass effect. Despite aggressive clinical presentation at onset, 181/257 (70%) of patients remained fully ambulatory (Expanded Disability Status Scale [EDSS] ≤4) after a 3.0-year median follow-up duration. Severe initial attack-related disability (EDSS ≥4) was more common in patients with motor symptoms (81/143 vs. 35/106, p < 0.0001), encephalopathy (20/143 vs. 2/106, p < 0.0001) and ADC restriction on initial MRI (42/63 vs. 15/33, p = 0.04). Poor long-term outcome (EDSS ≥4) was more common in patients with older onset age (41.9 ± 15 vs. 36.8 ± 15.6, p = 0.02) and motor symptoms at onset (49/76 vs. 66/171, p < 0.0001).

INTERPRETATION

Most TD patients should be considered part of the MS spectrum after excluding MOGAD and NMOSD. Motor symptoms and older age at presentation portend a poor outcome.

The nutritional risk in patients with neuromyelitis optica spectrum disorder

BACKGROUND

The effect of nutrition on chronic autoimmune diseases is well known. This study is the first to assess the nutritional status of patients with neuromyelitis optica spectrum disorder (NMOSD) by administering the Mini Nutritional Assessment (MNA), to explore the impacts of nutrition on patients' quality of life and to identify the factors associated with the nutritional status of NMOSD patients.

METHODS

Our study enrolled 70 NMOSD patients and 66 healthy controls. The following data were assessed: demographic information, disease features, and composite evaluations of life status, including nutrition, sleep, anxiety/depression, fatigue, and quality of life. Then, statistical analysis was performed.

RESULTS

The MNA score of NMOSD patients was 20.4 ± 3.3, which was significantly lower than that of HCs (23.3 ± 2.5, P = 0.002), especially for the dimensions of global evaluation and anthropometric assessment. Nearly 85% of patients were at risk of malnutrition or had definite malnutrition. The total MNA score was positively correlated with the patient's quality of life (P<0.01). Lower MNA scores were correlated with gender (P = 0.02), longer disease duration (P<0.001), more severe anxiety (P = 0.004), more severe depression (P = 0.003), more severe sleep disturbances (P<0.001), and more severe fatigue (P = 0.01). Sleep disturbance was revealed to be a significant independent factor for the NMOSD patients' malnutritional risk (P = 0.001).

CONCLUSIONS

These results suggest that the risk of malnutrition is very high in NMOSD patients and that malnutrition is closely related to their quality of life. Malnutrition among NMOSD patients is caused by a combination of various physiological and psychological factors. A multifaceted and personalized intervention is required to improve the prognosis of NMOSD.

The neuro-ophthalmological manifestations of NMOSD and MOGAD-a comprehensive review

Optic neuritis (ON) is one of the most frequently seen neuro-ophthalmic causes of vision loss worldwide. Typical ON is often idiopathic or seen in patients with multiple sclerosis, which is well described in the landmark clinical trial, the Optic Neuritis Treatment Trial (ONTT). However, since the completion of the ONTT, there has been the discovery of aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies, which are biomarkers for neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody-associated disease (MOGAD), respectively. These disorders are associated with atypical ON that was not well characterised in the ONTT. The severity, rate of recurrence and overall outcome differs in these two entities requiring prompt and accurate diagnosis and management. This review will summarise the characteristic neuro-ophthalmological signs in NMOSD and MOGAD, serological markers and radiographic findings, as well as acute and long-term therapies used for these disorders.

Differentiation between multiple sclerosis and neuromyelitis optica spectrum disorder using a deep learning model

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory disorders of the central nervous system (CNS) with similar characteristics. The differential diagnosis between MS and NMOSD is critical for initiating early effective therapy. In this study, we developed a deep learning model to differentiate between multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) using brain magnetic resonance imaging (MRI) data. The model was based on a modified ResNet18 convolution neural network trained with 5-channel images created by selecting five 2D slices of 3D FLAIR images. The accuracy of the model was 76.1%, with a sensitivity of 77.3% and a specificity of 74.8%. Positive and negative predictive values were 76.9% and 78.6%, respectively, with an area under the curve of 0.85. Application of Grad-CAM to the model revealed that white matter lesions were the major classifier. This compact model may aid in the differential diagnosis of MS and NMOSD in clinical practice.

Pediatric Neuromyelitis Optica Spectrum Disorder

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a demyelinating disease with a high relapse rate and risk of disability accrual. The condition is an astrocytopathy, with antibodies to the aquaporin-4 (AQP4) water channel being detected in AQP4-IgG seropositive disease. Presentation is uncommon in the pediatric age range, accounting for about 3%-5% of cases. NMOSD is more prevalent in populations of Black or East Asian ancestry. Core clinical syndromes include optic neuritis, acute myelitis, area postrema syndrome, acute brainstem syndrome, acute diencephalic syndrome, and symptomatic cerebral syndrome. First-line treatment options in pediatrics include rituximab, azathioprine, and mycophenolate mofetil. Over half of children with AQP4-IgG seropositive NMOSD develop permanent disability, particularly in visual and motor domains. Novel therapeutic targets in the adult population have been developed and are changing the treatment landscape for this disorder.

Identifying specific myelopathy etiologies in the evaluation of suspected myelitis: A retrospective analysis

BACKGROUND

Myelopathies require prompt etiologic diagnosis. We aimed to identify a specific myelopathy diagnosis in cases of suspected myelitis to highlight clinicoradiologic differences.

METHODS

In this retrospective, single-centre cohort of subjects with suspected myelitis referred to London Multiple Sclerosis (MS) Clinic between 2006 and 2021, we identified those with MS and reviewed the remaining charts for etiologic diagnosis based on clinical, serologic, and imaging details.

RESULTS

Of 333 included subjects, 318/333 (95.5%) received an etiologic diagnosis. Most (274/333, 82%) had MS or clinically isolated syndrome. Spinal cord infarction (n = 10) was the commonest non-inflammatory myelitis mimic characterized by hyperacute decline (n = 10/10, 100%), antecedent claudication (n = 2/10, 20%), axial owl/snake eye (n = 7/9, 77%) and sagittal pencillike (n = 8/9, 89%) MRI patterns, vertebral artery occlusion/stenosis (n = 4/10, 40%), and concurrent acute cerebral infarct (n = 3/9, 33%). Longitudinal lesions were frequent in aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4+NMOSD) (n = 7/7, 100%) and myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD) (n = 6/7, 86%), accompanied by bright spotty (n = 5/7, 71%) and central-grey-restricted (n = 4/7, 57%) T2-lesions on axial sequences, respectively. Leptomeningeal (n = 4/4, 100%), dorsal subpial (n = 4/4, 100%) enhancement, and positive body PET/CT (n = 4/4, 100%) aided the diagnosis of sarcoidosis. Spondylotic myelopathies had chronic sensorimotor presentations (n = 4/6, 67%) with relative bladder sparing (n = 5/6, 83%), localizable to sites of disc herniation (n = 6/6, 100%). Metabolic myelopathies showed dorsal column or inverted 'V' sign (n = 2/3, 67%) MRI T2-abnormality with B12 deficiency.

CONCLUSIONS

Although no single feature reliably confirms or refutes a specific myelopathy diagnosis, this study highlights patterns that narrow the differential diagnosis of myelitis and facilitate early recognition of mimics.

Serum proteins for monitoring and predicting visual function in patients with recent optic neuritis

It is unclear whether serum proteins can serve as biomarkers to reflect pathological changes and predict recovery in inflammation of optic nerve. We evaluated whether serum proteins could monitor and prognosticate optic neuritis (ON). We prospectively recruited consecutive patients with recent ON, classified as ON with anti-aquaporin-4 antibody (AQP4-ON), ON with anti-myelin oligodendrocyte glycoprotein antibody (MOG-ON), and double-seronegative ON (DSN-ON). Using ultrasensitive single-molecule array assays, we measured serum neurofilament light chain and glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF). We analyzed the markers according to disease group, state, severity, and prognosis. We enrolled 60 patients with recent ON (15 AQP4-ON; 14 MOG-ON; 31 DSN-ON). At baseline, AQP4-ON group had significantly higher serum GFAP levels than did other groups. In AQP4-ON group, serum GFAP levels were significantly higher in the attack state than in the remission state and correlated with poor visual acuity. As a prognostic indicator, serum BDNF levels were positively correlated with follow-up visual function in the AQP4-ON group (r = 0.726, p = 0.027). Serum GFAP reflected disease status and severity, while serum BDNF was identified as a prognostic biomarker in AQP4-ON. Serum biomarkers are potentially helpful for patients with ON, particularly those with AQP4-ON.

Tumefactive Demyelination in MOG Ab-Associated Disease, Multiple Sclerosis, and AQP-4-IgG-Positive Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVES

Studies on tumefactive brain lesions in myelin oligodendrocyte glycoprotein-immunoglobulin G (IgG)-associated disease (MOGAD) are lacking. We sought to characterize the frequency clinical, laboratory, and MRI features of these lesions in MOGAD and compare them with those in multiple sclerosis (MS) and aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4+NMOSD).

METHODS

We retrospectively searched 194 patients with MOGAD and 359 patients with AQP4+NMOSD with clinical/MRI details available from the Mayo Clinic databases and included those with ≥1 tumefactive brain lesion (maximum transverse diameter ≥2 cm) on MRI. Patients with tumefactive MS were identified using the Mayo Clinic medical record linkage system. Binary multivariable stepwise logistic regression identified independent predictors of MOGAD diagnosis; Cox proportional regression models were used to assess the risk of relapsing disease and gait aid in patients with tumefactive MOGAD vs those with nontumefactive MOGAD.

RESULTS

We included 108 patients with tumefactive demyelination (MOGAD = 43; AQP4+NMOSD = 16; and MS = 49). Tumefactive lesions were more frequent among those with MOGAD (43/194 [22%]) than among those with AQP4+NMOSD (16/359 [5%], p < 0.001). Risk of relapse and need for gait aid were similar in tumefactive and nontumefactive MOGAD. Clinical features more frequent in MOGAD than in MS included headache (18/43 [42%] vs 10/49 [20%]; p = 0.03) and somnolence (12/43 [28%] vs 2/49 [4%]; p = 0.003), the latter also more frequent than in AQP4+NMOSD (0/16 [0%]; p = 0.02). The presence of peripheral T2-hypointense rim, T1-hypointensity, diffusion restriction (particularly an arc pattern), ring enhancement, and Baló-like or cystic appearance favored MS over MOGAD (p ≤ 0.001). MRI features were broadly similar in MOGAD and AQP4+NMOSD, except for more frequent diffusion restriction in AQP4+NMOSD (10/15 [67%]) than in MOGAD (11/42 [26%], p = 0.005). CSF analysis revealed less frequent positive oligoclonal bands in MOGAD (2/37 [5%]) than in MS (30/43 [70%], p < 0.001) and higher median white cell count in MOGAD than in MS (33 vs 6 cells/μL, p < 0.001). At baseline, independent predictors of MOGAD diagnosis were the presence of somnolence/headache, absence of T2-hypointense rim, lack of T1-hypointensity, and no diffusion restriction (Nagelkerke R 2 = 0.67). Tumefactive lesion resolution was more common in MOGAD than in MS or AQP4+NMOSD and improved model performance.

DISCUSSION

Tumefactive lesions are frequent in MOGAD but not associated with a worse prognosis. The clinical, MRI, and CSF attributes of tumefactive MOGAD differ from those of tumefactive MS and are more similar to those of tumefactive AQP4+NMOSD with the exception of lesion resolution, which favors MOGAD.

Clinical and radiological profile of neuromyelitis optica spectrum disorders in a Pakistani cohort

BACKGROUND

The clinical and radiological characteristics of neuromyelitis optica spectrum disorder (NMOSD) from Pakistan is unknown. Our study aimed to describe the clinical and radiological features of NMOSD patients presenting to a Pakistani tertiary care center.

MATERIALS AND METHODS

This retrospective, observational study was conducted at the Neurology Department, Pakistan Institute of Medical Sciences between January 2017 and September 2021 (56 months). The study included patients diagnosed with neuromyelitis optica spectrum disorder (NMOSD) according to the 2015 International Panel for NMO Diagnosis (IPND) criteria, with the exclusion of patients under 12 years of age and those who tested positive for Myelin oligodendrocyte glycoprotein (MOG) IgG antibody. The patients were divided into two groups based on clinical presentation and the presence of NMO-IgG antibodies: NMO-IgG positive NMO (Seropositive NMO) and NMO-IgG negative (Seronegative NMO). The clinical features of NMOSD were recorded, and data was analyzed using SPSS version 26.0.

RESULTS

Among 204 patients with suspected demyelination, multiple sclerosis was diagnosed in 100 individuals (49.02%), while acute disseminated encephalomyelitis (ADEM), clinically isolated syndrome (CIS), and neuromyelitis optica (NMO) were found in 5 patients each (2.45%, 2.45%, and 17.65%, respectively). Out of 36 patients with NMO, 32 (88.89%) tested positive for NMO-Ab, while the remaining 4 (11.11%) were seronegative for both NMO and anti-MOG Abs. The mean age of NMO-positive patients who tested positive for NMO antibodies was 31.03±10.12 years, compared to 27.95±2.5 years for NMO-negative patients, though this difference was not statistically significant (p>0.05). Females were more commonly affected by NMO, accounting for 72.2% of the NMO-positive group, and there was a significant difference in clinical phenotypes between the two groups (p<0.05). The NMO-positive group predominantly had relapsing NMO presentation (75%), and 72.8% of these patients showed longitudinally extensive transverse myelitis on the MRI spine. Azathioprine was the most frequently administered treatment for positive NMO patients (69.44%), followed by rituximab and MMF. The follow-up period for the study participants lasted 24 months.

CONCLUSION

This is the first study on NMOSD cases in Pakistan. According to the present study, NMOSD is most prevalent among women in their forties. Relapsing NMO was the most common form of presentation. 89% of patients had antibodies against AQP4. 72.8% of patients suffered from LETM during the course of their disease. There are some features of our NMOSD cases that appear comparable with those around the world, despite some limitations in testing and access to care. It is clear that the clinical and radiological spectrums of patients with NMO and NMOSD in this cohort are similar. It is reasonable to suspect NMO if demyelinating episodes are not characteristic of MS.

Impact of dysautonomic symptom burden on the quality of life in Neuromyelitis optica spectrum disorder patients

BACKGROUND

This study aimed to investigate the clinical risk factors of dysautonomic symptom burden in neuromyelitis optica spectrum disorder (NMOSD) and its impact on patients' quality of life.

METHODS

A total of 63 NMOSD patients and healthy controls were enrolled. All participants completed the Composite Autonomic Symptom Score 31 (COMPASS-31) to screen for symptoms of autonomic dysfunction. A comprehensive clinical evaluation was performed on NMOSD patients, such as disease characteristics and composite evaluations of life status, including quality of life, anxiety/depression, sleep, and fatigue. Correlated factors of dysautonomic symptoms and quality of life were analyzed.

RESULTS

The score of COMPASS-31 in the NMOSD group was 17.2 ± 10.3, significantly higher than that in healthy controls (P = 0.002). In NMOSD patients, the higher COMPASS-31 score was correlated with more attacks (r = 0.49, P < 0.001), longer disease duration (r = 0.52, P < 0.001), severer disability (r = 0.50, P < 0.001), more thoracic cord lesions (r = 0.29, P = 0.02), more total spinal cord lesions (r = 0.35, P = 0.005), severer anxiety (r = 0.55, P < 0.001), severer depression (r = 0.48, P < 0.001), severer sleep disturbances (r = 0.59, P < 0.001), and severer fatigue (r = 0.56, P < 0.001). The disability, total spinal cord lesions, and fatigue were revealed to be independently associated factors. Further analysis revealed that the COMPASS-31 score was independently correlated with scores of all the domains of patients' quality of life scale (P < 0.05).

CONCLUSIONS

Dysautonomic symptom burden is correlated with decreased quality of life and certain clinical characteristics such as disability, the burden of spinal cord lesions, and fatigue in NMOSD patients. Investigation and proper management of autonomic dysfunction may help to improve the quality of life in patients with NMOSD.

ACT001 Relieves NMOSD Symptoms by Reducing Astrocyte Damage with an Autoimmune Antibody

Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system inflammatory demyelinating disease, the pathogenesis of which involves autoantibodies targeting the extracellular epitopes of aquaporin-4 on astrocytes. We neutralized the AQP4-IgG from NMOSD patient sera using synthesized AQP4 extracellular epitope peptides and found that the severe cytotoxicity produced by aquaporin-4 immunoglobin (AQP4-IgG) could be blocked by AQP4 extracellular mimotope peptides of Loop A and Loop C in astrocyte protection and animal models. ACT001, a natural compound derivative, has shown anti-tumor activity in various cancers. In our study, the central nervous system anti-inflammatory effect of ACT001 was investigated. The results demonstrated the superior astrocyte protection activity of ACT001 at 10 µM. Furthermore, ACT001 decreases the behavioral score in the mouse NMOSD model, which was not inferior to Methylprednisolone Sodium Succinate, the first-line therapy of NMOSD in clinical practice. In summary, our study showed that astrocytes are protected by specific peptides, or small molecular drugs, which is a new strategy for the treatment of NMOSD. It is possible for ACT001 to be a promising therapy for NMOSD.

MOG and AQP4 Antibodies among Children with Multiple Sclerosis and Controls

OBJECTIVE

The purpose of this study was to determine the frequency of myelin oligodendrocyte glycoprotein (MOG)-IgG and aquaporin-4 (AQP4)-IgG among patients with pediatric-onset multiple sclerosis (POMS) and healthy controls, to determine whether seropositive cases fulfilled their respective diagnostic criteria, to compare characteristics and outcomes in children with POMS versus MOG-IgG-associated disease (MOGAD), and identify clinical features associated with final diagnosis.

METHODS

Patients with POMS and healthy controls were enrolled at 14 US sites through a prospective case-control study on POMS risk factors. Serum AQP4-IgG and MOG-IgG were assessed using live cell-based assays.

RESULTS

AQP4-IgG was negative among all 1,196 participants, 493 with POMS and 703 healthy controls. MOG-IgG was positive in 30 of 493 cases (6%) and zero controls. Twenty-five of 30 patients positive with MOG-IgG (83%) had MOGAD, whereas 5 of 30 (17%) maintained a diagnosis of multiple sclerosis (MS) on re-review of records. MOGAD cases were more commonly in female patients (21/25 [84%] vs 301/468 [64%]; p = 0.044), younger age (mean = 8.2 ± 4.2 vs 14.7 ± 2.6 years; p < 0.001), more commonly had initial optic nerve symptoms (16/25 [64%] vs 129/391 [33%]; p = 0.002), or acute disseminated encephalomyelitis (ADEM; 8/25 [32%] vs 9/468 [2%]; p < 0.001), and less commonly had initial spinal cord symptoms (3/20 [15%] vs 194/381 [51%]; p = 0.002), serum Epstein-Barr virus (EBV) positivity (11/25 [44%] vs 445/468 [95%]; p < 0.001), or cerebrospinal fluid oligoclonal bands (5/25 [20%] vs 243/352 [69%]; p < 0.001).

INTERPRETATION

MOG-IgG and AQP4-IgG were not identified among healthy controls confirming their high specificity for pediatric central nervous system (CNS) demyelinating disease. Five percent of those with prior POMS diagnoses ultimately had MOGAD; and none had AQP4-IgG positivity. Clinical features associated with a final diagnosis of MOGAD in those with suspected MS included initial ADEM phenotype, younger age at disease onset, and lack of EBV exposure. ANN NEUROL 2023;93:271-284.

Differentiating Multiple Sclerosis From AQP4-Neuromyelitis Optica Spectrum Disorder and MOG-Antibody Disease With Imaging

BACKGROUND AND OBJECTIVES

Relapsing-remitting multiple sclerosis (RRMS), aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may have overlapping clinical features. There is an unmet need for imaging markers that differentiate between them when serologic testing is unavailable or ambiguous. We assessed whether imaging characteristics typical of MS discriminate RRMS from AQP4-NMOSD and MOGAD, alone and in combination.

METHODS

Adult, nonacute patients with RRMS, APQ4-NMOSD, and MOGAD and healthy controls were prospectively recruited at the National Hospital for Neurology and Neurosurgery (London, United Kingdom) and the Walton Centre (Liverpool, United Kingdom) between 2014 and 2019. They underwent conventional and advanced brain, cord, and optic nerve MRI and optical coherence tomography (OCT).

RESULTS

A total of 91 consecutive patients (31 RRMS, 30 APQ4-NMOSD, and 30 MOGAD) and 34 healthy controls were recruited. The most accurate measures differentiating RRMS from AQP4-NMOSD were the proportion of lesions with the central vein sign (CVS) (84% vs 33%, accuracy/specificity/sensitivity: 91/88/93%, p < 0.001), followed by cortical lesions (median: 2 [range: 1-14] vs 1 [0-1], accuracy/specificity/sensitivity: 84/90/77%, p = 0.002) and white matter lesions (mean: 39.07 [±25.8] vs 9.5 [±14], accuracy/specificity/sensitivity: 78/84/73%, p = 0.001). The combination of higher proportion of CVS, cortical lesions, and optic nerve magnetization transfer ratio reached the highest accuracy in distinguishing RRMS from AQP4-NMOSD (accuracy/specificity/sensitivity: 95/92/97%, p < 0.001). The most accurate measures favoring RRMS over MOGAD were white matter lesions (39.07 [±25.8] vs 1 [±2.3], accuracy/specificity/sensitivity: 94/94/93%, p = 0.006), followed by cortical lesions (2 [1-14] vs 1 [0-1], accuracy/specificity/sensitivity: 84/97/71%, p = 0.004), and retinal nerve fiber layer thickness (RNFL) (mean: 87.54 [±13.83] vs 75.54 [±20.33], accuracy/specificity/sensitivity: 80/79/81%, p = 0.009). Higher cortical lesion number combined with higher RNFL thickness best differentiated RRMS from MOGAD (accuracy/specificity/sensitivity: 84/92/77%, p < 0.001).

DISCUSSION

Cortical lesions, CVS, and optic nerve markers achieve a high accuracy in distinguishing RRMS from APQ4-NMOSD and MOGAD. This information may be useful in clinical practice, especially outside the acute phase and when serologic testing is ambiguous or not promptly available.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that selected conventional and advanced brain, cord, and optic nerve MRI and OCT markers distinguish adult patients with RRMS from AQP4-NMOSD and MOGAD.

Therapeutic strategies in NMOSD and MOGAD patients: A multicenter cohort study in Latin America

PURPOSE

This study describes the therapeutic strategies in NMOSD and MOGAD adopted by neurologists to treat both conditions in Latin America (LATAM) with main focus on rituximab (RTX) and the disease outcome.

METHODS

retrospective study in a cohort of NMOSD and MOGAD patients followed in specialized MS/NMOSD centers from eight countries and 14 LATAM reference centers. Demographics and clinical characteristics were collected. RTX strategies on naïve (for rituximab) patients were summarized as follows: scheme A: two 1000 mg infusions 15 days apart and repeated every 6 months; scheme B: four 375 mg/m2 infusions every week for 4 weeks and repeated every 6 months; scheme C: one 1000 mg infusions and repeated every 6 months; scheme D: other scheme used. Relapse rate and adverse events during follow-up were analyzed considering the different RTX schemes. Poisson and logistic regression analysis were used to assess baseline aspects and disease activity during follow-up.

RESULTS

A total of 217 patients were included. 197 were NMOSD patients (164, 83.2% AQP4-IgG seropositive and 16.7% seronegative) and 20 were MOGAD patients. The most frequent long-term treatment was RTX in both groups (48.2% and 65% for NMOSD and MOGAD patients, respectively). The most common RTX regimen used in 79 (83.1%) patients was two 1000 mg infusions 15 days apart and repeat every 6 months. Relapses under RTX treatment were observed in 21 (22.1%) patients. Relapses after RTX treatment were associated with higher EDSS (OR 1.75, 95%CI 1.44-2.34, p = 0.03) and higher ARR pre-RTX (OR = 2.17, 95% CI 1.72-3.12, p = 0.002) but not with RTX regimen (OR = 1.10, 95% CI 0.89-1.21, p = 0.60).

CONCLUSION

the most strategy used in LATAM was RTX with two 1000 mg infusions 15 days apart. Relapses during follow up were not associated with RTX regimen used.

The Characteristics of Cognitive Proficiency in Patients with Acute Neuromyelitis Optica Spectrum Disease and its Correlation with Serum Aquaporin-4 Antibody Titer

Objective: To explore the characteristics and dynamic evolution of cognitive impairment in patients with neuromyelitis optica spectrum disorder (NMOSD). Methods: Twenty-five patients with acute NMOSD and 30 age-matched healthy individuals were consecutively recruited in this study. The Montreal Cognitive Assessment (MoCA), Chinese Version of Rey Auditory Vocabulary Learning Test (CRAVLT), Verbal Fluency Test (VFT), Digital Span Test (DST), Paced Auditory Serial Addition Task 3/2s version (PASAT-3/2), Rey−Osterrieth Complex Figure Test (ROCF) and Stroop Color and Word Test (CWT) were used to evaluate cognitive function. The correlations between cognitive function and serum aquaporin-4 (AQP-4) antibody titer were analyzed. Results: Sixty-four percent of patients with acute NMOSD had cognitive dysfunction. MoCA (p < 0.001), CRAVLT-N7 (p = 0.004), CRAVLT-N8 (p = 0.011), ROCF-C (p = 0.005), ROCF-R (p < 0.001), PASAT-3 (p = 0.013), PASAT-2 (p = 0.001) and CWT-A (p = 0.017) were significantly worse in patients with acute NMOSD than those in control group. During follow-up visits, significant differences of serum AQP-4 antibody titers were still noted in NMOSD patients (p < 0.001), while no significant differences were found by MoCA. Conclusion: A high number of patients with acute NMOSD suffer from cognitive dysfunction. Serum AQP-4 antibody titers can decrease during disease remission, while obvious cognitive decline in these patients still exists.

Disability outcomes in NMOSD and MOGAD patients: data from a nationwide registry in Argentina

The objective was to evaluate time to reach an EDSS of 4, 6, and 7 in NMOSD and MOGAD patients included in the Argentinean MS and NMOSD registry (RelevarEM, NCT 03,375,177).

METHODS

NMOSD patients diagnosed according to 2015 criteria and with MOGAD were identified. Patients with at least 3 years of follow-up and periodic clinical evaluations with EDSS outcomes were included. AQP4-antibody and MOG-antibody status was recorded, and patients were stratified as seropositive and seronegative for AQP4-antibody. EDSS of 4, 6, and 7 were defined as dependent variables. Log rank test was used to identify differences between groups.

RESULTS

Registry data was provided for a total of 137 patients. Of these, seventy-five presented AQP4-ab-positive NMOSD, 45 AQP4-ab-negative NMOSD, and 11 MOGAD. AQP4-ab status was determined by cell-based assay (CBA) in 72% of NMOSD patients. MOG-ab status was tested by CBA in all cases. Mean time to EDSS of 4 was 53.6 ± 24.5 vs. 63.1 ± 32.2 vs. 44.7 ± 32 months in seropositive, seronegative NMOSD, and MOGAD, respectively (p = 0.76). Mean time to EDSS of 6 was 79.2 ± 44.3 vs. 75.7 ± 48.6 vs. 54.7 ± 50 months in seropositive, seronegative NMOSD, and MOGAD (p = 0.23), while mean time to EDSS of 7 was 86.8 ± 54 vs. 80.4 ± 51 vs. 58.5 ± 47 months in seropositive, seronegative NMOSD, and MOGAD (p = 0.39).

CONCLUSION

No differences were observed between NMOSD (seropositive and seronegative) and MOGAD in survival curves.

Comparison of Fixed and Live Cell-Based Assay for the Detection of AChR and MuSK Antibodies in Myasthenia Gravis

BACKGROUND AND OBJECTIVES

Live cell-based assay (CBA) can detect acetylcholine receptors (AChRs) or muscle-specific tyrosine kinase (MuSK) antibodies (Abs) in a proportion of patients with radioimmunoassay (RIA)-double seronegative myasthenia gravis (dSN-MG). A commercial fixed CBA for AChR and MuSK Abs has recently become available; however, comparative studies on fixed and live CBAs are lacking. In this study, we compared the performance of fixed and live CBAs in patients with RIA-dSN MG and assessed their sensitivity in RIA-positive MG samples and their specificity.

METHODS

AChR and MuSK Abs were tested in 292 serum samples from 2 Italian MG referral centers by live and fixed CBAs: 192 from patients with MG and 100 from controls. All samples had been previously assessed by RIA: 66 were AChR positive, 40 MuSK positive, and 86 dSN. All controls were negative. Two independent raters assessed the CBA results. Fixed and live CBAs were compared with the McNemar test; interrater and interlaboratory agreement were assessed with Cohen's kappa or interclass correlation coefficient (ICC), as appropriate.

RESULTS

In 86 RIA-dSN samples, fixed CBA detected Abs in 10 cases (11.6%, 95% CI 5.7-20.3), whereas live CBA detected Abs in 16 (18.6%, 95% CI 11.0-28.5) (p = 0.0143). Of these sera, those positive by fixed CBA were also positive by live CBA. In addition, live CBA could detect MuSK Abs in 4 and AChR Abs in 2 samples that were negative by fixed CBA, providing an 8% (95% CI 2.9-16.6) further increase in the Ab detection rate. These results were confirmed by flow cytometry. In the RIA-positive cohort, the sensitivity for AChR Abs was 98.5% (95% CI 91.9%-99.9%) for fixed CBA and 100% (95% CI 94.6-100) for live CBA (p = 0.1573). For both assays, the sensitivity for MuSK Abs was 100% (95% CI 91.2-100), and the specificity was 100% (95% CI 96.4-100). Interrater agreement was almost perfect for live and fixed CBAs (Cohen's kappa 0.972 and 0.978, respectively), alike interlaboratory agreement. Interrater agreement for the CBA score ranged from good to excellent (ICC: 0.832-0.973).

DISCUSSION

Fixed CBA represents a valuable alternative to RIA for AChR and MuSK Ab detection in patients with MG and could be considered as a first-step diagnostic test. Live CBA can be useful in the serologic evaluation of RIA- and fixed CBA-negative samples.

Glial fibrillary acidic protein as a biomarker in neuromyelitis optica spectrum disorder: a current review

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, often debilitating neuroinflammatory disease, whose predominant clinical manifestations are longitudinally extensive transverse myelitis and optic neuritis. About 80% of the patients with an NMOSD phenotype have pathogenic autoantibodies against the astrocyte water channel aquaporin-4 (AQP4-IgG). While therapeutic options for NMOSD have greatly expanded in recent years, well-established biomarkers for prognosis or treatment response are still lacking. Glial fibrillary acidic protein (GFAP) is mainly expressed in astrocytes and can be detected in cerebrospinal fluid (CSF) and blood of patients with NMOSD.

AREAS COVERED

Here, we comprehensively review the current knowledge on GFAP as a biomarker in NMOSD.

EXPERT OPINION

In patients with AQP4-IgG⁺ NMOSD, GFAP levels are elevated in CSF and serum during acute attacks and correlate with disability, consistent with the pathophysiology of this antibody-mediated astrocytopathy. Serum GFAP levels tend to be higher in AQP4-IgG⁺ NMOSD than in its differential diagnoses, multiple sclerosis, and myelin oligodendrocyte antibody-associated disease. Importantly, serum GFAP levels in AQP4-IgG⁺ NMOSD during remission may be predictive of future disease activity. Serial serum GFAP measurements are emerging as a biomarker to monitor disease activity in AQP4-IgG⁺ NMOSD and could have the potential for application in clinical practice.

Aquaporin-4 IgG neuromyelitis optica spectrum disorder onset after Covid-19 vaccination: Systematic review

Neuromyelitis optica spectrum disorder (NMOSD) is rarely reported following Coronavirus disease 2019 (COVID-19) vaccination. We identified 16 cases of new onset NMOSD with positive aquaporin-4 IgG (AQP4-IgG) following COVID-19 vaccination. Transverse myelitis was the most common clinical presentation (75%). Most patients received high dose steroids for acute treatment and maintenance therapy was started in 12 patients (75%). Twelve patients (75%) had improvement of their symptoms at the time of discharge or follow-up. The included cases share similar epidemiology and natural course to non-vaccine related cases. Clinicians should be aware of possible post-vaccination NMOSD to help with earlier diagnosis and treatment.

Parallel roles of neuroinflammation in feline and human epilepsies

Autoimmune encephalitis refers to a group of disorders characterised by a non-infectious encephalitis, often with prominent seizures and surface neuronal autoantibodies. AE is an important cause of new-onset refractory status epilepticus in humans and is frequently responsive to immunotherapies including corticosteroids, plasma exchange, intravenous immunoglobulin G and rituximab. Recent research suggests that parallel autoantibodies can be detected in non-human mammalian species. The best documented example is leucine-rich glioma-inactivated 1 (LGI1)-antibodies in domestic cats with limbic encephalitis (LE). In this review, we discuss the role of neuroinflammation and autoantibodies in human and feline epilepsy and LE.

Nontraumatic Spinal Cord Injury: Epidemiology, Etiology and Management

The spinal cord is a conduit within the central nervous system (CNS) that provides ongoing communication between the brain and the rest of the body, conveying complex sensory and motor information necessary for safety, movement, reflexes, and optimization of autonomic function. After a traumatic spinal cord injury (SCI), supraspinal influences on the peripheral nervous system and autonomic nervous system (ANS) are disrupted, leading to spastic paralysis, sympathetic blunting, and parasympathetic dominance, resulting in cardiac dysrhythmias, systemic hypotension, bronchoconstriction, copious respiratory secretions, and uncontrolled bowel, bladder, and sexual dysfunction. This article outlines the pathophysiology of the less reported nontraumatic SCI (NTSCI), its classification, its influence on sensory/motor function, and introduces the probable comorbidities associated with SCI that will be discussed in more detail in the accompanying manuscripts of this special issue. Finally, management strategies for NTSCI will be provided.

Rare variants and HLA haplotypes associated in patients with neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) are rare, debilitating autoimmune diseases of the central nervous system. Many NMOSD patients have antibodies to Aquaporin-4 (AQP4). Prior studies show associations of NMOSD with individual Human Leukocyte Antigen (HLA) alleles and with mutations in the complement pathway and potassium channels. HLA allele associations with NMOSD are inconsistent between populations, suggesting complex relationships between the identified alleles and risk of disease. We used a retrospective case-control approach to identify contributing genetic variants in patients who met the diagnostic criteria for NMOSD and their unaffected family members. Potentially deleterious variants identified in NMOSD patients were compared to members of their families who do not have the disease and to existing databases of human genetic variation. HLA sequences from patients from Belgrade, Serbia, were compared to the frequency of HLA haplotypes in the general population in Belgrade. We analyzed exome sequencing on 40 NMOSD patients and identified rare inherited variants in the complement pathway and potassium channel genes. Haplotype analysis further detected two haplotypes, HLA-A*01, B*08, DRB1*03 and HLA-A*01, B*08, C*07, DRB1*03, DQB1*02, which were more prevalent in NMOSD patients than in unaffected individuals. In silico modeling indicates that HLA molecules within these haplotypes are predicted to bind AQP4 at several sites, potentially contributing to the development of autoimmunity. Our results point to possible autoimmune and neurodegenerative mechanisms that cause NMOSD, and can be used to investigate potential NMOSD drug targets.

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

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