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

Probable eculizumab-associated hepatotoxicity in a patient with neuromyelitis optica: a case report

OBJECTIVES

Neuromyelitis optica (NMO) is an inflammatory, autoimmune and demyelinating disease of the central nervous system and is often characterized by attacks of severe optic neuritis and long segment myelitis. Identifying the disease-specific pathogenic anti-AQP4 autoantibody in NMOSD has allowed the development of highly effective disease-modifying drugs in the treatment phase. Eculizumab is a humanized antibody that binds to complement C5 and inhibits the formation of the C5b-induced membrane attack complex. It is approved for treating many diseases in which tissue damage is accompanied by complement (such as neuromyelitis optica, myasthenia gravis, autoimmune hemolytic anemia and paroxysmal hemoglobinuria).

METHODS

We present a patient diagnosed with NMO who developed possible drug-induced liver injury three months after the start of eculizumab treatment.

RESULT

After discontinuing eculizumab treatment, liver function tests gradually regressed in a month.

CONCLUSIONS

Eculizumab-associated hepatotoxicity is a previously unreported adverse event in NMOSD patients. Therefore, patients should be monitored for liver function tests during eculizumab treatment, and care should be taken for hepatotoxicity. If hepatotoxicity is detected while under eculizumab treatment, patients should be investigated for other drug use, complementary food supplementation, or possible autoimmune hepatitis, and other potential causes should be excluded.

A new perspective on therapies involving B-cell depletion in autoimmune diseases

It has been rediscovered in the last fifteen years that B-cells play an active role in autoimmune etiology rather than just being spectators. The clinical success of B-cell depletion therapies (BCDTs) has contributed to this. BCDTs, including those that target CD20, CD19, and BAFF, were first developed to eradicate malignant B-cells. These days, they treat autoimmune conditions like multiple sclerosis and systemic lupus erythematosus. Particular surprises have resulted from the use of BCDTs in autoimmune diseases. For example, even in cases where BCDT is used to treat the condition, its effects on antibody-secreting plasma cells and antibody levels are restricted, even though these cells are regarded to play a detrimental pathogenic role in autoimmune diseases. In this Review, we provide an update on our knowledge of the biology of B-cells, examine the outcomes of clinical studies employing BCDT for autoimmune reasons, talk about potential explanations for the drug's mode of action, and make predictions about future approaches to targeting B-cells other than depletion.

Intruders or protectors - the multifaceted role of B cells in CNS disorders

B lymphocytes are immune cells studied predominantly in the context of peripheral humoral immune responses against pathogens. Evidence has been accumulating in recent years on the diversity of immunomodulatory functions that B cells undertake, with particular relevance for pathologies of the central nervous system (CNS). This review summarizes current knowledge on B cell populations, localization, infiltration mechanisms, and function in the CNS and associated tissues. Acute and chronic neurodegenerative pathologies are examined in order to explore the complex, and sometimes conflicting, effects that B cells can have in each context, with implications for disease progression and treatment outcomes. Additional factors such as aging modulate the proportions and function of B cell subpopulations over time and are also discussed in the context of neuroinflammatory response and disease susceptibility. A better understanding of the multifactorial role of B cell populations in the CNS may ultimately lead to innovative therapeutic strategies for a variety of neurological conditions.

Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management

This manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings.

Myasthenia gravis: Molecular mechanisms and promising therapeutic strategies

Myasthenia gravis (MG) is a type of autoimmune disease caused by the blockage of neuromuscular junction transmission owing to the attack of autoantibodies on transmission-related proteins. Related antibodies, such as anti-AChR, anti-MuSK and anti-LRP4 antibodies, can be detected in most patients with MG. Although traditional therapies can control most symptoms, several challenges remain to be addressed, necessitating the development of more effective and safe treatment strategies for MG. With the in-depth exploration on the mechanism and immune targets of MG, effective therapies, especially therapies using biologicals, have been reported recently. Given the important roles of immune cells, cytokines and intercellular interactions in the pathological process of MG, B-cell targeted therapy, T-cell targeted therapy, proteasome inhibitors targeting plasma cell, complement inhibitors, FcRn inhibitors have been developed for the treatment of MG. Although these novel therapies exert good therapeutic effects, they may weaken the immunity and increase the risk of infection in MG patients. This review elaborates on the pathogenesis of MG and discusses the advantages and disadvantages of the strategies of traditional treatment and biologicals. In addition, this review emphasises that combined therapy may have better therapeutic effects and reducing the risk of side effects of treatments, which has great prospects for the treatment of MG. With the deepening of research on immunotherapy targets in MG, novel opportunities and challenges in the treatment of MG will be introduced.

Treatment transitions in neuromyelitis optica spectrum disorder increase risk for disease advancement

BACKGROUND

People with neuromyelitis optica spectrum disorder (PwNMOSD) commonly switch between disease modifying therapies, yet the consequence of transitions remains unknown. We aimed to understand if treatment transitions due to medical, non-medical, and tolerability reasons were related to disease progression.

METHODS

A retrospective study of medical records for PwNMOSD was performed between 2008 and 2022. A comprehensive clinical timeline was created for each person including details related to treatment history and associated clinical and radiological outcomes (i.e., hospital admission, relapses, and MRI advancement). If a transition occurred, the reason for the switch was categorized as being due to medical, non-medical, or tolerability issues. A proportional hazards model was created, and the assumptions were tested based on weighted residuals.

RESULTS

The cohort included 164 aquaporin-4 IgG positive NMOSD subjects with 89 (79 female; median disease duration (range) = 10.1 years (y) (1.7-32.8)) people switching therapies at least once (once: 42; twice: 26; three times: 12; four times: 6; 5 or more times: 3). A similar amount of higher efficacy therapies was used by PwNMOSD that switched due to a non-medical/tolerability or a medical-related reason. The results of the recurrent event survival analysis revealed that after an initial transition due to non-medical/tolerability reasons, the risk of a hospital admission, relapse, and MRI advancement decreases by 40.3 % (p = 0.005), 53.1 % (p = 0.002), and 65.9 % (p = 0.005), respectively. However, with each additional discontinuation due to non-medical/tolerability reasons, the risk of hospitalization increased by 25.2 % (p = 0.0003) and risk for MRI advancement increased by 41.9 % (p = 0.03). For transitions due to medical reasons, a significant increased risk of MRI advancement by 32.2 % (p = 0.005) for the first switch was identified with no associated observed risk with each additional discontinuation (p = 0.33). Within the first six months after stopping a medication due to non-medical/tolerability reasons, the rate of starting a new medication was less (p<0.0001) when compared to a discontinuation due to a medical-related event.

CONCLUSIONS

The risk associated with the time course of treatment transitions for people with NMOSD may assist in transforming the way healthcare providers bridge the gap between therapies and the approach to the timing of a switch. These data highlight additional factors that may be equatable to the efficacy of prescribed treatments in the prevention of acute neurological events.

A Clinical Approach to Existing and Emerging Therapeutics in Neuromyelitis Optica Spectrum Disorder

PURPOSE OF REVIEW

Neuromyelitis optica spectrum disorder (NMOSD) is a rare but highly disabling disease of the central nervous system. Unlike multiple sclerosis, disability in NMOSD occurs secondary to relapses that, not uncommonly, lead to blindness, paralysis, and death. Recently, newer, targeted immunotherapies have been trialed and are now in the treatment arsenal. We have endeavoured to evaluate the current state of NMOSD therapeutics.

RECENT FINDINGS

This review provides a pragmatic evaluation of recent clinical trials and post-marketing data for rituximab, inebilizumab, satralizumab, eculizumab, and ravalizumab, contrasted to older agents. We also review contemporary issues such as treatment in the context of SARS-CoV2 infection and pregnancy. There has been a dramatic shift in NMOSD morbidity and mortality with earlier and improved disease recognition, diagnostic accuracy, and the advent of more effective, targeted therapies. Choosing a maintenance therapy remains nuanced depending on patient factors and accessibility. With over 100 putative agents in trials, disease-free survival is now a realistic goal for NMOSD patients.

International Delphi Consensus on the Management of AQP4-IgG+ NMOSD: Recommendations for Eculizumab, Inebilizumab, and Satralizumab

BACKGROUND AND OBJECTIVES

Neuromyelitis optica spectrum disorder (NMOSD) is a rare debilitating autoimmune disease of the CNS. Three monoclonal antibodies were recently approved as maintenance therapies for aquaporin-4 immunoglobulin G (AQP4-IgG)-seropositive NMOSD (eculizumab, inebilizumab, and satralizumab), prompting the need to consider best practice therapeutic decision-making for this indication. Our objective was to develop validated statements for the management of AQP4-IgG-seropositive NMOSD, through an evidence-based Delphi consensus process, with a focus on recommendations for eculizumab, inebilizumab, and satralizumab.

METHODS

We recruited an international panel of clinical experts in NMOSD and asked them to complete a questionnaire on NMOSD management. Panel members received a summary of evidence identified through a targeted literature review and provided free-text responses to the questionnaire based on both the data provided and their clinical experience. Responses were used to generate draft statements on NMOSD-related themes. Statements were voted on over a maximum of 3 rounds; participation in at least 1 of the first 2 rounds was mandatory. Panel members anonymously provided their level of agreement (6-point Likert scale) on each statement. Statements that failed to reach a predefined consensus threshold (≥67%) were revised based on feedback and then voted on in the next round. Final statements were those that met the consensus threshold (≥67%).

RESULTS

The Delphi panel comprised 24 experts, who completed the Delphi process in November 2021 after 2 voting rounds. In round 1, 23/25 statements reached consensus and were accepted as final. The 2 statements that failed to reach consensus were revised. In round 2, both revised statements reached consensus. Twenty-five statements were agreed in total: 11 on initiation of or switching between eculizumab, inebilizumab, and satralizumab; 3 on monotherapy/combination therapy; 7 on safety and patient population considerations; 3 on biomarkers/patient-reported outcomes; and 1 on research gaps.

DISCUSSION

An established consensus method was used to develop statements relevant to the management of AQP4-IgG-seropositive NMOSD. These international statements will be valuable for informing individualized therapeutic decision-making and could form the basis for standardized practice guidelines.

High-efficacy therapies reduce clinical and radiological events more effectively than traditional treatments in neuromyelitis optica spectrum disorder

BACKGROUND

People with neuromyelitis optica spectrum disorder (pwNMOSD) experience debilitating neurological attacks, resulting in permanent disability.

OBJECTIVE

To evaluate if high-efficacy treatment was better than traditional agents at preventing disease advancement in pwNMOSD.

METHODS

A retrospective study of pwNMOSD at one academic center was performed. Timelines were created for treatments subjects were exposed to along with clinical/radiological events related to disease worsening. High-efficacy treatments included eculizumab, inebilizumab, satralizumab, rituximab, ocrelizumab, tocilizumab, and sarilumab while therapies such as azathioprine, methotrexate, cyclophosphamide, and mycophenolate mofetil were classified as traditional agents. Poisson regression and mixed effects logistics models were constructed, and a subject-specific random intercept was used for intrasubject correlation.

RESULTS

Of 189 pwNMOSD identified, 161 were aquaporin-4 IgG positive (AQP4 +) with 92 (77 female; median disease duration (MDD) (range) of 6.6 years (y) (1.2-18.6)) exposed only to high-efficacy therapy, 33 (28 female; 10.4 y (0.8-32.7)) only to traditional therapy, and 64 (54 female; 10.8 y (0.7-20.2)) to both. High-efficacy treatments reduced the rate of MRI advancement by 62.4% (95% CrI = [- 86.9%, - 16.8%]), relapses by 99.8% (95% CrI = [- 99.9%, - 99.6%]), and hospitalizations by 99.3% (95% CrI = [- 99.6%, - 98.8%]) when compared to traditional treatments. For AQP4 + subjects, a 655.7-fold increase in the odds of new spinal cord lesion development (95% CrI = [+ 37.4-fold, + 3239.5-fold]) was observed with traditional agents (p < 0.0001).

CONCLUSION

High-efficacy treatments maximize opportunity for preventing disease advancement in newly diagnosed and established pwNMOSD.

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.

Factors associated with the misdiagnosis of neuromyelitis optica spectrum disorder

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune condition that is associated with severe disability. Approximately 40% of individuals are misdiagnosed with multiple sclerosis (MS) or other diseases. We aimed to define factors that influence the misdiagnosis of people with NMOSD and provide strategies for reducing error rates.

METHODS

A retrospective study was performed involving all people with a confirmed diagnosis of NMOSD within a single academic institution. Comprehensive clinical timelines were constructed for each individual that included presenting symptoms, provider type and timing of evaluations, aquaporin 4-IgG (AQP4) results, and MRI scans. Two-sample comparisons of continuous and categorial variables were performed for people accurately diagnosed with NMOSD and those originally misdiagnosed with another medical condition. A subanalysis of only AQP4-IgG positive people was also performed.

RESULTS

The study cohort included 199 people fulfilling International Panel criteria for NMOSD with 71 people (62 female; mean age at first symptom presentation (standard deviation (SD)) = 32.8 years (y) (SD 16.1)) being initially misdiagnosed and 128 people (106 female; 41.14y (SD 15.41)) who were accurately diagnosed. Of the 199 people with NMOSD, 166 had a positive serostatus. Identified factors associated with misdiagnosis, regardless of AQP4-IgG serostatus, were the presence of protracted nausea/vomiting/hiccups without any accompanying neurological symptoms, 23 (32.4%) versus 16 (12.5%) (p = 0.001), a longer median (range) time to see a neuroimmunology specialist 4.2y (0.14-31.8) versus 0.5y (0.0-21.2) (p<0.0001), and a delay in acquiring an MRI study, 4.7y (0.0-27.3) versus 0.3y (0.0-20.2) (p<0.0001). A greater proportion of people misdiagnosed were identified with a negative live-cell based AQP4-IgG serum test result, 13/13 (100%) versus 22/114 (19.3%) (p<0.0001). Additionally, the mean (SD) time between a first negative and successive live-cell based AQP4-IgG positive test result was greater for people misdiagnosed with another condition, 3.9y (SD 5.0) versus 1.5y (SD 2.1) (p = 0.01). Although not significant between groups, a rash was also reported in 63/199 people with NMOSD, with 31/63 having an anti-nuclear antibody titer ≥ 1:160.

CONCLUSION

Defined factors can help guide both generalists and specialists in the pursuit of strategies aimed at efficiently diagnosing those with NMOSD such that effective care can be delivered.

An update on biologic treatments for neuromyelitis optica spectrum disorder

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Challenging Cases in Neuroimmunology

Neuroimmunology is rapidly evolving field extending from well-known, but incompletely understood conditions like multiple sclerosis, to novel antibody-mediated disorders, of which dozens have been described in the past 10 years. The ongoing expansion in knowledge needed to effectively diagnose and treat these patients presents myriad challenges for clinicians. Here, we discuss six informative cases from our institution. By highlighting these challenging cases, we hope to instill fundamental points on the nuances of diagnosis and management for conditions including tumefactive multiple sclerosis, antibody-mediated encephalitis, antiphospholipid antibody syndrome, neuromyelitis optica, and myelin oligodendrocyte glycoprotein IgG-associated disease.

Clinical and Genetic Analysis in Pediatric Patients with Multiple Sclerosis and Related Conditions: Focus on DR Genes of the Major Histocompatibility Complex

Introduction:

There are several diseases recognized as variants of MS: post-infectious acute disseminated encephalitis, multiple sclerosis (MS), Rasmussen leukoencephalitis and Schilder's leukoencephalitis and related, but separate neuroimmune condition – Neuromyelitis Devic’s. In Kazakhstan diagnosis of such diseases was rare and immune modified treatment was only admitted after the age of 18. Clinical and immunogenetic study of MS spectrum diseases in Kazakhstan would allow to justify early targeted treatment.

Objective:

The aim of the study was to investigate genes of the main complex of human histocompatibility (MHC) associated with diseases of MS spectrum in Kazakhstani population.

Methods:

Complex clinical, neuroimaging and immunogenetic studies were performed in 34 children (24 girls, 10 boys) aged 4 to 18 years. 21 children were diagnosed with MS (11 Kazakh origin and 10 – Russian; 4 boys, 17 girls), 7 with leucoencephalitis (all Kazakh, 5 boys, 2 girls) and 6 with Devic neuromyelitis optica (all Kazakh, 1 boy, 5 girls). Genotyping of HLA DRB1, DQA1, DQB1 genes was performed for all patients.

Results:

MS group was characterized by classical relapsing-remitting MS. Predominant haplotype as a linkage complex was DRB1*15:01~DQA1*01:02~DQB1*06:02 in 20 (47.6%) of 42 DR-alleles, in 16 (76.2%) patients. MS relative risk (RR) was 13,36 for ethnic Kazakhs and RR=5,55 in Russians.

Leukoencephalitis had 7 children, with 28.6% mortality rate. The haplotype DRB1*15:01~DQA1*01:02~DQB1*06:02 as a linkage complex was detected 3 patients (4 alleles), RR=5,88.

Devic’s neuromyelitis optica (NMO) clinical course was characterized by fast and prolonged progression. There was predominance of DRB1*14 allele with RR=3,38.

Conclusion:

Summarizing, in the Kazakh population the haplotype DRB1*15:01∼DQA1*01:02∼DQB1*06:02 as a linkage complex was associated with prediction to MS and leukoencephalitis, but not to Devic’s NMO. Our study highlights the importance of awareness of MS and related disorders diagnosis which allows to implement early admission of disease-modified treatment in pediatric MS in Kazakhstan.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article reviews the cardinal clinical features, distinct immunopathology, current diagnostic criteria, relapse-related risk factors, emerging biomarkers, and evolving treatment strategies pertaining to neuromyelitis optica spectrum disorders (NMOSD).

RECENT FINDINGS

The discovery of the pathogenic aquaporin-4 (AQP4)-IgG autoantibody and characterization of NMOSD as an autoimmune astrocytopathy have spearheaded the identification of key immunologic therapeutic targets in this disease, including but not limited to the complement system, the interleukin 6 (IL-6) receptor, and B cells. Accordingly, four recent randomized controlled trials have demonstrated the efficacy of three new NMOSD therapies, namely eculizumab, satralizumab, and inebilizumab.

SUMMARY

Currently, NMOSD poses both diagnostic and treatment challenges. It is debated whether individuals who are seropositive for myelin oligodendrocyte glycoprotein (MOG)-IgG belong within the neuromyelitis optica spectrum. This discussion is fueled by disparities in treatment responses between patients who are AQP4-IgG seropositive and seronegative, suggesting different immunopathologic mechanisms may govern these conditions. As our understanding regarding the immune pathophysiology of NMOSD expands, emerging biomarkers, including serum neurofilament light chain and glial fibrillary acidic protein (GFAP), may facilitate earlier relapse detection and inform long-term treatment decisions. Future research focal points should include strategies to optimize relapse management, restorative treatments that augment neurologic recovery, and practical solutions that promote equitable access to approved therapies for all patients with NMOSD.

Contemporary management challenges in seropositive NMOSD

Neuromyelitis optica spectrum disorders (NMOSD) is an inflammatory disorder of the central nervous system that presents unique management challenges. Neurologic disability in NMOSD is directly linked to acute attacks, therefore, relapse prevention is an overarching goal of care. To this end, identifying effective biomarkers that predict relapse onset and severity is of critical importance. As treatment becomes more precision-based and patient-centred, clinicians will need to be familiar with managing circumstances of particular vulnerability for patients with NMOSD, including infection, pregnancy, and the post-partum phase. The discovery of the pathogenic aquaporin-4 Immunoglobulin G (AQP4 IgG) autoantibody almost 20 years ago ultimately distinguished NMOSD as an autoimmune astrocytopathy and helped spearhead recent therapeutic advancements. Targeted therapies, including eculizumab, satralizumab, and inebilizumab, approved for use in aquaporin-4 immunoglobulin G (AQP4 IgG) seropositive patients with NMOSD will likely improve outcomes, but there are formidable costs involved. Importantly, seronegative patients continue to have limited therapeutic options. Moving forward, areas of research exploration should include relapse prevention, restorative therapies, and initiatives that promote equitable access to approved therapies for all people living with NMOSD.

Cytokine dynamics and targeted immunotherapies in autoimmune encephalitis

Autoimmune encephalitides constitute a diverse group of immune-mediated central nervous system disorders mainly characterized by the presence of antibodies targeting neuronal or glial antigens. Despite the notable contribution of antibody discovery to the understanding of their physiopathology, the specific immune cells and inflammatory mediators involved in autoimmune encephalitis are still poorly defined. However, cytokines have recently emerged as crucial signalling molecules in the pathogenesis of autoimmune encephalitis. Cytokines are biologically active, soluble, low-molecular-weight proteins or glycoproteins involved in a wide variety of physiological functions, including central nervous system development and homeostasis, immune surveillance, as well as proliferation and maturation of immune cells. Since unbalanced cytokine expression is considered a hallmark of many autoimmune central nervous system disorders, their identification and quantification has become an essential element in personalized medicine applied to the field of neuroimmunology. Several studies have explored the cytokine profile of autoimmune encephalitis, but their interpretation and comparison is challenging due to their small sample sizes and extremely high heterogeneity, especially regarding the cytokines analysed, type of sample used, and associated neural antibody. Only the cytokine profile of anti-N-methyl-D-aspartate receptor encephalitis has extensively been investigated, with findings suggesting that, although humoral immunity is the main effector, T cells may also be relevant for the development of this disorder. A better understanding of cytokine dynamics governing neuroinflammation might offer the opportunity of developing new therapeutic strategies against specific immune cells, cytokines, antibodies, or intracellular signalling cascades, therefore leading to better outcomes and preventing undesired side effects of the presently used strategies. In this review, we first summarize the current knowledge about the role of cytokines in the pathogenesis of autoimmune encephalitis, combining theoretical analysis with experimental validations, to assess their suitability as clinical biomarkers. Second, we discuss the potential applicability of the novel targeted immunotherapies in autoimmune encephalitis depending on the immunobiology of the associated antibody, their limitations, as well as the main limitations that should be addressed in future studies.

Can Immune Tolerance Be Re-established in Neuromyelitis Optica?

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that primarily affects the optic nerves and spinal cord of patients, and in some instances their brainstem, diencephalon or cerebrum as spectrum disorders (NMOSD). Clinical and basic science knowledge of NMO has dramatically increased over the last two decades and it has changed the perception of the disease as being inevitably disabling or fatal. Nonetheless, there is still no cure for NMO and all the disease-modifying therapies (DMTs) are only partially effective. Furthermore, DMTs are not disease- or antigen-specific and alter all immune responses including those protective against infections and cancer and are often associated with significant adverse reactions. In this review, we discuss the pathogenic mechanisms of NMO as they pertain to its DMTs and immune tolerance. We also examine novel research therapeutic strategies focused on induction of antigen-specific immune tolerance by administrating tolerogenic immune-modifying nanoparticles (TIMP). Development and implementation of immune tolerance-based therapies in NMO is likely to be an important step toward improving the treatment outcomes of the disease. The antigen-specificity of these therapies will likely ameliorate the disease safely and effectively, and will also eliminate the clinical challenges associated with chronic immunosuppressive therapies.

Neuromyelitis Optica in a Healthy Female After Severe Acute Respiratory Syndrome Coronavirus 2 mRNA-1273 Vaccine

Neuromyelitis optica spectrum disorder is an autoimmune demyelinating disease with high relative prevalence in the East Asian population. Clinical manifestations include optic neuritis, longitudinally extensive transverse myelitis, area postrema syndrome, brainstem syndromes, and diencephalic syndromes. In this case report, we present a case of neuromyelitis optica spectrum disorder that developed 10 days after the first dose of the severe acute respiratory syndrome coronavirus 2 mRNA-1273 vaccine. The patient was a previously healthy White female, completely independent and functional at baseline. She presented with bilateral lower-extremity numbness/tingling, weakness, and urinary retention. Although her neuromyelitis optica IgG was negative, the MRI was consistent with neuromyelitis optica involving and spanning longitudinally the C6-T2 vertebrae. She was treated with IV steroids and her symptoms improved. Given the novelty of the COVID-19 vaccines and the paucity of literature regarding their adverse effects, case reports such as ours provide unique information that aids healthcare providers in accurately diagnosing and treating patients, ultimately minimizing long-term neurologic deficits.

Aquaporin-4 Autoantibody Detection by ELISA: A Retrospective Characterization of a Commonly Used Assay

Objective

Aquaporin-4 (AQP4) serum autoantibodies are detected by a variety of methods. The highest sensitivity is achieved with cell-based assays, but the enzyme-linked immunosorbent assay (ELISA) is still commonly utilized by clinicians worldwide.

Methods

We performed a retrospective review to identify all patients at the University of Utah who had AQP4 ELISA testing at ARUP Laboratories from 2010 to 2017. We then reviewed their diagnostic evaluation and final diagnosis based on the ELISA titer result.

Results

A total of 750 tests for the AQP4 ELISA were analyzed, and 47 unique patients with positive titers were identified. Less than half of these patients (49%) met the clinical criteria for neuromyelitis optica spectrum disorder (NMOSD). In cases of low positive titers (3.0–7.9 U/mL, n = 19), the most common final diagnosis was multiple sclerosis (52.6%). In the moderate positive cohort (8.0–79.9 U/mL, n = 14), only a little more than half the cohort (64.3%) had NMOSD. In cases with high positives (80–160 U/mL, n = 14), 100% of patients met clinical criteria for NMOSD.

Conclusions

Our data illustrates diagnostic uncertainty associated with the AQP4 ELISA, an assay that is still commonly ordered by clinicians despite the availability of more sensitive and specific tests to detect AQP4 autoantibodies in patients suspected of having NMOSD. In particular, low positive titer AQP4 ELISA results are particularly nonspecific for the diagnosis of NMOSD. The importance of accessibility to both sensitive and specific AQP4 testing cannot be overemphasized in clinical practice.

Cells to the Rescue: Emerging Cell-Based Treatment Approaches for NMOSD and MOGAD

Cell-based therapies are gaining momentum as promising treatments for rare neurological autoimmune diseases, including neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease. The development of targeted cell therapies is hampered by the lack of adequate animal models that mirror the human disease. Most cell-based treatments, including HSCT, CAR-T cell, tolerogenic dendritic cell and mesenchymal stem cell treatment have entered early stage clinical trials or have been used as rescue treatment in treatment-refractory cases. The development of antigen-specific cell-based immunotherapies for autoimmune diseases is slowed down by the rarity of the diseases, the lack of surrogate outcomes and biomarkers that are able to predict long-term outcomes and/or therapy effectiveness as well as challenges in the manufacturing of cellular products. These challenges are likely to be overcome by future research.

Immune reconstitution therapy in NMOSD

IMPORTANCE

NMO spectrum disorders [NMOSD] is a relapsing autoimmune disorder with attacks of optic neuritis (ON) and transverse myelitis (TM). A large proportion of NMOSD patients have no or a partial recovery after relapse.

OBSERVATIONS

The neuro-immunological community now has a number of indicated agents for NMOSD therapy including eculizumab [Soliris®], inebilizumab (Uplizna®) and satralizumab (Enspryng®) with different mechanisms of action (MOA), rapidity of the onset of action (OOA) and issues of long-term safety. Autologous hematopoietic stem cell transplantation (AHSCT) may be another therapeutic option.

CONCLUSIONS AND RELEVANCE

The advantages of eculizumab are preservation of immunosurveillance, immediate onset of action and persistent efficacy but frequent IV administration and cost are important drawbacks. Inebilizumab allows a slight decrease in relapse free subjects over time but decreases B and plasmablast cell disease-inducing pathogenic antibody production. However, inebilizumab may cause immunosuppression. Satralizumab is immunomodulatory and self-administration but has delayed onset of action. AHSCT may be the best therapeutic option for the prevention and therefore the progression of NMO. In NMO, control the complement (eculizumab), reconstitute the immune system (AHSCT), transition to immunomodulation (satralizumab) and reserve immunosuppression (inebilizumab) as 4th line. AHSCT might also be used as rescue therapy for severe breakthrough disease after NMO-DMTs.

Neuromyelitis Optica Spectrum Disorder Treatment-Current and Future Prospects

Neuromyelitis optica (NMO) is an immune-mediated demyelinative disorder of the central nervous system affecting mainly the optical nerves and the spinal cord. The recurrent course of the disease, with exacerbations and incomplete remissions, causes accumulating disability, which has a profound impact upon patients’ quality of life. The discovery of antibodies against aquaporin 4 (AQP4) and their leading role in NMO etiology and the formulation of diagnostic criteria have improved appropriate recognition of the disease. In recent years, there has been rapid progress in understanding the background of NMO, leading to an increasing range of treatment options. On the basis of a review of the relevant literature, the authors present currently available therapeutic strategies for NMO as well as ongoing research in this field, with reference to key points of immune-mediated processes involved in the background of the disease.