Maintenance plasma exchange therapy for steroid-refractory neuromyelitis optica

Immunoadsorption as maintenance therapy for refractory neuromyelitis optica spectrum disorder

Background

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing autoimmune disease of the central nervous system, affecting mainly optic nerves and spinal cord. NMOSD pathophysiology is associated with anti-aquaporin-4 (AQP4) immunoglobulin G (IgG) autoantibodies. Rapid extracorporeal elimination of autoantibodies with apheresis techniques, such as immunoadsorption (IA), was proven to be an effective treatment of NMOSD attacks. Data on the long-term use of IA to prevent attacks or progression of NMOSD are lacking.

Objectives

The aim of this study was to evaluate efficacy and safety of maintenance IA for preventing recurrence of NMOSD attacks in patients refractory to other immunotherapies.

Design

Case study.

Methods

Retrospective analysis of two female patients with severe NMOSD refractory to conventional immunotherapies was performed. Both patients had responded to tryptophan IA (Tr-IA) as attack therapy and subsequently were treated with biweekly maintenance Tr-IA.

Results

Patient 1 (AQP4-IgG seropositive, age 42 years) had 1.38 attacks of optic neuritis per year within 10.1 years before commencing regular Tr-IA. With maintenance Tr-IA for 3.1 years, one mild attack occurred, which was responsive to steroid pulse therapy. Expanded Disability Status Scale (EDSS) was stable at 5.0. Visual function score of the last eye improved from 3 to 1. Patient 2 (AQP4-IgG seronegative, age 43 years) experienced 1.7 attacks per year, mainly acute myelitis and optic neuritis, during the period of 10.0 years before the start of Tr-IA. During regular Tr-IA treatment, no further NMOSD attack occurred. The patient was clinically stable without any additional immunosuppressive treatment for 5.3 years. EDSS improved from 6.0 to 5.0, and the ambulation score from 7 to 1. Tolerability of Tr-IA was good in both patients. No serious adverse events occurred during long-term clinical trajectories.

Conclusion

Tr-IA was well tolerated as maintenance treatment and resulted in clinical stabilization of two patients with highly active NMOSD, who were refractory to standard drug therapy.

Efficacy and safety of plasma exchange or immunoadsorption for the treatment of option neuritis in demyelinating diseases: A systematic review and meta-analysis

BACKGROUND

There are no systematic reviews yet that evaluated the effects of PE/IA in patients with optic neuritis (ON) in demyelinating diseases. A meta-analysis of available study is needed to further explore the value of plasma exchange (PE) or immunoadsorption (IA) in treating ON in demyelinating diseases.

METHODS

All relevant articles published on PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), VIP Database, Wanfang, Sinomed and ophthalmology professional websites were searched. Study characteristics, demographic characteristics, clinical features and outcome measures were extracted. Response rate, adverse events (AE) rate, serious adverse event (SAE) rate, the log of the minimum angle of resolution (logMAR), visual outcome scale (VOS) and expanded disability status scales (EDSS) were evaluated using a random-effects model.

RESULTS

35 studies were included between 1985 and 2020, containing 1191 patients. The response rates of PE and IA in acute attack of ON were 68% and 82% respectively. LogMAR (-0.60 to - 1.42) and VOS (-1.10 to -1.82) had been significantly improved from within 1 month to more than 1 month after PE treatment. Besides, we found that logMAR improved 1.78, 0.95 and 0.38, respectively ,when the time from symptom onset to the first PE/IA was less than 21 days, 21-28 days, and more than 28 days. The pooled mean difference of EDSS was -1.14.Adverse effects rate in patients with PE or IA were 0.20 and 0.06, respectively.

CONCLUSION

The meta-analysis provided evidence that PE/IA treatment was an effective and safe intervention, and it is recommended that early initiation of PE/IA treatment is critical.

The Role of Plasma Exchange in the Treatment of Refractory Autoimmune Neurological Diseases: a Narrative Review

Autoimmune neurological disorders are commonly treated with immunosuppressive therapy. In patients with refractory conditions, standard immunosuppression is often insufficient for complete recovery or to prevent relapses. These patients rely on other treatments to manage their disease. While treatment of refractory cases differs between diseases, intravenous immunoglobulin, plasma exchange (PLEX), and immune-modulating treatments are commonly used. In this review, we focus on five autoimmune neurological disorders that were the themes of the 2018 Midlands Neurological Society meeting on PLEX in refractory neurology: Autoimmune Encephalitis (AE), Multiple Sclerosis (MS), Neuromyelitis Optica Spectrum disorders (NMOSD), Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Myasthenia Gravis (MG). The diagnosis of inflammatory neuropathies is often challenging, and while PLEX can be very effective in refractory autoimmune diseases, its ineffectiveness can be confounded by misdiagnosis. One example is POEMS syndrome (characterized by Polyneuropathy Organomegaly, Endocrinopathy, Myeloma protein, Skin changes), which is often wrongly diagnosed as CIDP; and while CIDP responds well to PLEX, POEMS does not. Accurate diagnosis is therefore essential. Success rates can also differ within 'one' disease: e.g. response rates to PLEX are considerably higher in refractory relapsing remitting MS compared to primary or secondary progressive MS. When sufficient efforts are made to correctly pinpoint the diagnosis along with the type and subtype of refractory autoimmune disease, PLEX and other immunotherapies can play a valuable role in the patient management.

PLEX: the best first-line treatment in nmosd attacks experience at a single center in Colombia

Objective

Primary outcome was to evaluate complete improvement at six months after acute treatment in NMOSD relapses.

Methods

Retrospective observational cohort study of patients with diagnosis of NMOSD admitted for acute attacks. We performed an explanatory analysis using the univariate, bivariate and multivariate logistic regression approach. We compared survival curves using the Kaplan Meier analysis and estimated the median time for the main outcome.

Results

In the univariate analysis, basal EDSS score, AQP4-IgG positivity, PLEX as a first-line treatment (IVMP + PLEX), less systemic complications related to acute treatment and total attack history were independently associated with complete improvement at six months. After adjusting for confounding variables and using multivariate analysis by Cox Regression, positive AQ4-IgG (HR 0.04, 95% CI: 0.02–0.66) and IVMP + PLEX (HR 5.1, 95% CI: 3.9–66.4), were kept as independent factors associated to time to complete improvement. Time from admission to PLEX initiation and complete improvement at six months had a median of seven days (95% CI: 5.2–8.8). In secondary effects, there were no statistical differences between the groups.

Conclusions

PLEX + IVMP is the treatment of choice for NMOSD relapses and should be initiated as early as possible.

[Treatment of antibody-mediated encephalomyelitis : Strategies for the treatment of neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease]

BACKGROUND

Antibody-mediated encephalomyelitis, such as neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and glial fibrillary acidic protein (GFAP) antibody-associated astrocytopathy belong to a group of newly described autoimmune diseases.

AIM

Presentation of the treatment of antibody-mediated encephalomyelitis with a focus on NMOSD and MOGAD.

METHODS

Selective literature search in PubMed taking the consultation version of the S2k guidelines of the German Society of Neurology (DGN) on the diagnosis and treatment of multiple sclerosis (MS), NMOSD and MOG IgG-associated diseases into account.

RESULTS

Acute relapses are treated with high-dose steroid pulse therapy or apheresis therapy (plasma exchange or immunoadsorption). It is crucial to start treatment as quickly as possible and apheresis therapy can also be used as first-line treatment under certain conditions. For prophylactic immunotherapy, steroids, classical immunosuppressants and monoclonal antibodies with specific mechanisms of action are used. Eculizumab, inebilizumab and satralizumab are the first drugs approved for NMOSD. Symptomatic treatment and neurorehabilitation are important complementary measures.

CONCLUSION

Treatment of antibody-mediated encephalomyelitis differs from treatment of multiple sclerosis and requires specific measures.

Optimal management of neuromyelitis optica spectrum disorder with aquaporin-4 antibody by oral prednisolone maintenance therapy

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing neuroinflammatory disease associated with aquaporin-4 antibody. Since disabilities in patients with NMOSD accumulate with attacks, relapse prevention is crucially important for improving long-term outcomes. Corticosteroids are inexpensive and promising drugs for relapse prevention in NMOSD, but few studies have analysed the efficacy of corticosteroids in NMOSD, especially regarding the appropriate dosing and tapering regimens.

METHODS

A single-center, retrospective analysis of corticosteroid therapy in aquaporin-4 antibody-positive NMOSD patients fulfilling the 2015 international consensus diagnostic criteria was conducted.

RESULTS

Medical records of a total of 89 Japanese patients with aquaporin-4 antibody-positive NMOSD seen at Department of Neurology, Tohoku University Hospital (2000~2016) were reviewed. At the last follow-up, 66% of the patients were treated with prednisolone (PSL) monotherapy, and the percentage of those receiving PSL monotherapy or a combination of PSL and other immunosuppressants increased from 17.5% in 2000 to 94.1% in 2016. On the other hand, annualised relapse rate (ARR) decreased from 0.78 (13 attacks in 200 person-months) in 2000 to 0.07 (5 attacks in 819 person-months) in 2016. Under PSL treatment, the mean ARR significantly decreased, and disabilities stabilized (PSL treatment vs no-medication; ARR: 0.21 vs 0.98, P < 0.01, Expanded Disability Status Scale score change: +0.02 vs +0.89, P < 0.01, observation periods: 60.1 vs 68.2 months, P=0.26). Using Kaplan-Meier curves, the 10-year relapse-free rate was 46.5% with PSL monotherapy and 7.1% with no medication (hazard ratio: 0.069, 95% confidence interval [CI] 0.024-0.199, P < 0.01). Rapid tapering of PSL (10 mg or less in one year and/or 5 mg or less in two years after clinical attacks) was associated with frequent relapses compared to gradual tapering (more than 10 mg in one year and more than 5 mg in two years after clinical attacks) (rapid vs gradual, 36.7% vs 17.7%, odds ratio 2.69, 95% CI 1.12-6.44, P = 0.02). However, even with PSL of 5 mg/day or less, the relapse rate was low after two years of acute treatment (before vs after, 53.8% vs 13.6%, odds ratio 0.12, 95% CI 0.03-0.50, P < 0.01). Nine patients needed additional immunosuppressants due to insufficient relapse prevention by PSL monotherapy. PSL monotherapy was generally well tolerated, but seven patients had severe adverse events, mainly bone fractures (5 with bone fracture, 1 with femoral capital necrosis and 1 with cerebral infarction).

CONCLUSION

Our study suggests that PSL monotherapy is effective to prevent relapses in about half of patients with aquaporin-4 antibody-positive NMOSD if the doses are gradually reduced. Although it is important to have a treatment strategy tailored to each patient, this study provides evidence that PSL monotherapy can be an option for relapse prevention in some patients with NMOSD.

Timing of plasma exchange for neuromyelitis optica spectrum disorders: A meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSDs) are autoimmune astrocytopathies with predominant involvement of the optic nerves and spinal cord. The current management is high-dose intravenous methylprednisolone, followed by apheresis therapy if it fails. We aimed to investigate plasma exchange (PE) benefits in corticosteroid-refractory NMOSDs.

METHODS

From Embase, PubMed, Cochrane, Web of Science, and Clinical Trials, we identified PE-based studies published between Jan 2007 and Dec 2019. We pooled the information of these studies in a binomial meta-analysis. We investigated the factors affecting the efficacy of PE and its adverse events. The effectiveness of PE was assessed using the Expanded Disability Status Scale (EDSS). The timing of PE initiation was assessed using Spearman correlation analysis.

RESULTS

We included 561 records and identified 8 observational studies, including 228 NMOSD patients. The mean time to the initiation of PE was 11 days, and the average volume of each exchange was 1.5-2 L. PE treatment reduced the mean EDSS score by -1.04 (95% CI, -1.44 to -0.64). The initiation time of PE significantly affected the outcome (EDSS reduction) (P = 0.01; 95% CI, -1.30 to 0.28). In the ≤ 7-day and 8-23-day groups, the mean EDSS decreased by 0.64 (95% CI, -0.93 to -0.34) and 1.41 (95% CI, -1.79 to -1.02), respectively. In addition, PE showed the same efficacy for alleviating the symptoms of NMOSDs, regardless of the day between 8 to 23 days on which it was performed (P = 0.29). Thirty-five (20.8%) of the 168 patients had adverse events.

CONCLUSION

PE can ameliorate severe NMOSDs. PE effectiveness was associated with the duration between disease and the initiation of PE, and the optimal timing for PE initiation is 8 to 23 days after the onset of the disease.

Effect of plasma exchange in neuromyelitis optica spectrum disorder: A systematic review and meta-analysis

OBJECTIVE

To conduct systematic review and meta-analysis for the efficacy of therapeutic plasma exchange (TPE) for neuromyelitis optica spectrum disorder (NMOSD) with an acute attack.

METHODS

Systematic review was performed using EMBASE and OVID/Medline database. The eligible studies must be the studies of NMOSD patients treated with TPE during the acute phase. They must report treatment outcomes using either Expanded Disability Status Scale (EDSS) or visual acuity (VA) before and after the therapy. Pooled mean difference (MD) was then calculated by combining MDs of each study using the random-effects model.

RESULTS

Fifteen studies were identified; eleven with 241 NMOSD patients reported EDSS outcome and four studies with 103 NMOSD reported visual outcomes. The meta-analysis demonstrated a significantly decreased in EDSS after TPE treatment for NMOSD with an acute attack with the pooled MD of 0.83 (95% CI, 0.26-1.40; I² 69%) comparing pretreatment to immediate posttreatment and 2.13 (95% CI, 1.55-2.70; I² 31%) comparing pretreatment to posttreatment at 6 months to 1-year follow-up. Unfortunately, only one of the four studies evaluating visual outcomes reported standard deviation in association with mean LogMAR; therefore, the meta-analysis cannot be conducted. Nonetheless, all studies consistently demonstrated the benefit of TPE with improved VA and/or LogMAR after treatment.

INTERPRETATION

This systematic review and meta-analysis showed the benefit of TPE during the NMOSD attack with a significantly improved disability status immediately after treatment and during follow-up.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Clinical, neuroimaging and therapeutic response in AQP4-positive NMO patients from India

BACKGROUND

Neuromyelitis Optica (NMO) is an autoimmune astrocytopathic disorder due to AQP4 antibodies.

OBJECTIVES

To analyse clinical, neuroimaging features in NMO patients and assess the efficacy of various therapeutics.

METHODS

AQP4+ve NMO patients were diagnosed based on consensus diagnostic criteria.

RESULTS

101 AQP4+ve NMO patients were seen with female (90) predominance. Adult population (71.3%) formed the larger group followed by pediatric (19.8%) and late-onset (8.9%). Myelopathy (36.2%) was most commonly seen followed by optic neuritis (19.1%), brainstem (17.1%), opticomyelopathy (16.1%), area postrema involvement (10.5%) and encephalopathy (1%). Encephalopathy and brainstem/cerebellar involvement were most common in pediatric population while opticomyelopathy was more common in late-onset patients. Hyperintensities of lower medulla was seen in 67.3% subjects and 49.5% had involvement of obex. Differential T2 hyperintensity of the long segment myelitis was found in 30.7%. Plasmapheresis was given in 71 subjects followed by maintenance therapy. Most of them showed significant improvement with EDSS score of 1 in 30.7%.

CONCLUSIONS

Clinical manifestations in AQP4+ve NMO patients may vary depending on the age at onset of illness. MRI features affecting cervicomedullary junction, obex, differential T2 hyperintensities of the spinal cord may form a useful diagnostic clue. Plasmapheresis is helpful in achieving remission along with immunomodulation.

Therapeutic plasma exchange in paediatric neurology: a critical review and proposed treatment algorithm

Therapeutic plasma exchange (TPE) has been a key immunotherapeutic strategy in numerous neurological syndromes, predominantly during the acute phase of illness. This paper reviews the indications, strength of evidence, and safety of TPE in children with neurological conditions. The rarity of these immune conditions in children, alongside an often incomplete understanding of their pathobiology, has limited the development of a robust scientific rationale for TPE therapy and the feasibility of conducting larger controlled trials. TPE continues to be used, but is a costly therapy with common adverse effects. Uncertainty remains over how to compare the different TPE methods, the optimal dosage of therapy, and monitoring and integration of TPE with other immunotherapies. Further studies are also required to define the indications and benefits of TPE and assess evolving technologies such as immunoadsorption.

WHAT THIS PAPER ADDS

Studies investigating therapeutic plasma exchange (TPE) are small and mainly uncontrolled. They provide evidence for the efficacy of TPE in childhood neuro-inflammatory conditions. TPE is generally well tolerated provided key adverse effects are anticipated and avoided. Systematic dosing and objective assessment of treatment effect should be priorities for future research.

Treatment strategies for neuromyelitis optica

Neuromyelitis optica (NMO) is an autoimmune demyelinating disease with pathogenic autoantibodies that act against the astrocyte water channel protein, i.e. aquaporin-4: the disease is associated with recurrent episodes of optic neuritis (ON) and transverse myelitis, often resulting in severe disability. The main goals in treatment of NMO include acute symptomatic therapy and long-term stabilization of symptoms by preventing relapse. In recent years, ongoing randomized controlled trials in NMO patients have studied evidence for treatment. Briefly, acute-stage management (with pulse therapy using corticosteroids and/or plasmapheresis) and maintenance therapy (including rituximab, mycophenolate mofetil, and azathioprine) have been recommended in some case series and retrospective studies. Because of the high prevalence of liver disease, all NMO patients in Taiwan should be screened for hepatitis B and C before treatment is initiated. Although immunosuppression and plasma exchange are the mainstays of therapy for NMO ON, several selective and potentially therapeutic strategies targeting specific steps in NMO pathogenesis including blockers of NMO-IgG binding and inhibitors of granulocyte function have been evaluated in recent years.

Therapeutic Efficacy of Plasma Exchange in Neuromyelitis Optica

Background

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that selectively affects the optic nerves and spinal cord and generally follows a relapsing course. Therapeutic plasma exchange (TPE) appears to be effective in patients with central nervous system inflammatory demyelinating disease who do not respond to first-line corticosteroid treatment.

Objective

We represent a retrospective review of the use of TPE in the treatment of an acute attack of NMO in five patients who failed to respond to initial immunomodulatory treatment.

Materials and Methods

We evaluated the effect of TPE on the degree of recovery from NMO. It was performed using a single volume plasma exchange with intermittent cell separator (Hemonetics Mobile Collection System plus) by femoral or central line access and scheduled preferably on alternate-day intervals from 8 to 10 days. Both subjective and objective clinical response to TPE was estimated, and final assessment of response was made at the time of the last TPE in the series.

Results

All patients were severely disabled before the initiation of TPE and they were female; with the mean age of these patients was 52.5 years (range = 36-69 years), the median age of NMO diagnosis was 49.4 years (range = 35-65 years), and the median duration of disease was 2.6 years (range = 0-5 years). Out of five patients, three had a history of bilateral optic neuritis, and all patients were anti-against protein aquaporin-4antibody positive. Totally 24 TPE procedures were performed on five patients, the mean time of start of TPE in the acute attack was 18.6 days. Patients were severely disabled at the initiation of TPE (range = expanded disability status scale 6.5-9), and improvement was observed early in the course of TPE treatment in most patients.

Conclusion

The present study provides clinical support for the importance of TPE in refractory acute attack in NMO. However, with new diagnostic technologies and increasing clinical awareness, we may see a more improved ways of TPE in these patients in the future; hence, TPE is more effective modality of treatment as it also removed the antibodies.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Treatment of neuromyelitis optica

PURPOSE OF REVIEW

Neuromyelitis optica (NMO) is an antibody-mediated inflammatory disease of the central nervous system with a predilection for the optic nerves, spinal cord and certain brain regions. It has a distinct pathogenesis relating to aquaporin-4 autoimmunity and complement-mediated injury. This knowledge has translated into targeted efforts to develop novel, disease-specific treatments. In this review, we discuss evidence supporting the use of currently available treatments for acute exacerbations and for long-term disease modification. We also discuss the risks and benefits of available and emerging immunotherapies.

RECENT FINDINGS

Early, accurate diagnosis of NMO with appropriate acute and long-term immunosuppressive treatment is of prime importance for the prevention of disability associated with this disease. Standard measures for the management of acute exacerbations include intravenous methylprednisolone and plasmapheresis. First-line, long-term immunotherapies for NMO include azathioprine, mycophenolate mofetil and rituximab. Three randomized controlled treatment trials evaluating these agents are currently being conducted. In addition, there are numerous emerging therapies that are based upon current understanding of the disease immunopathogenesis.

SUMMARY

NMO is an autoimmune disease that is separate from multiple sclerosis. Better understanding of its antibody and complement-dependent pathophysiology has proven to be critical for the formulation of current and future treatment strategies.

Present and Future Therapies in Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSD) are important evolving entities, which have reached much attention in the recent years. NMOSD are characterized by inflammatory lesions in the optic nerves, spinal cord, and central parts of the brain, as well as an autoimmune process directed against aquaporin-4. As disability in NMOSD accumulates by inflammatory damage from attacks, both the treatment and prevention of attacks are decisive for the long-term outcome. NMOSD attacks are treated with high-dose intravenous corticosteroids and apheresis therapies, in particular therapeutic plasma exchange. In cases of incomplete remission, escalation of attack treatment is recommended. Preventive therapy is immunosuppressive and should by commenced as early as possible. Apart from classical immunosuppressants such as azathioprine and mycophenolate mofetil, repurposed biologicals are increasingly used. B-cell depletion with rituximab and other agents, inhibition of the interleukin-6 receptor with tocilizumab, and blockade of complement-mediated damage by eculizumab all are promising therapeutic strategies evaluated in randomized controlled trials. In this review, we will discuss present and future immunotherapies for NMOSD and also consider combination of treatments, plasma, cellular and other therapies. Current advances in immunopathological knowledge are translated into innovative concepts and begin a new era of NMOSD therapy.

Isotetrandrine Reduces Astrocyte Cytotoxicity in Neuromyelitis Optica by Blocking the Binding of NMO-IgG to Aquaporin 4

OBJECTIVE

Neuromyelitis optica (NMO) is a severe neurological demyelinating autoimmune disease that affects the optic nerves and spinal cord with no cure and no FDA-approved therapy. Research over the last decade revealed that the binding of NMO-IgG to the water channel protein astrocyte aquaporin 4 (AQP4) might be the primary cause of NMO pathogenesis. The purpose of this study was to identify potential blockers of NMO-IgG and AQP4 binding.

METHODS

We developed a two-step screening platform consisting of a reporter cell-based high-throughput screen assay and a cell viability-based assay. Purified NMO-IgG from NMO patient serum and transfected Chinese hamster lung fibroblast V79 cells stably expressing human M23-AQP4 were used for primary screening of 40,000 small molecule fractions from 500 traditional Chinese herbs.

RESULTS

Thirty-six positive fractions were identified, of which 3 active fractions (at 50 μg/ml) were found to be from the same Chinese traditional herb Mahonia japonica (Thunb.). A bioactivity-guided method based on a primary screening assay for blocking activity led to the isolation of an active single natural compound, isotetrandrine, from the 3 fractions. Our immunofluorescence staining results showed that isotetrandrine can block NMO-IgG binding to AQP4 without affecting the expression and function of AQP4. It can also inhibit NMO-IgG binding to astrocyte AQP4 in NMO patient sera and block NMO-IgG-dependent complement-mediated cytotoxicity with the IC50 at ∼3 μM.

CONCLUSIONS

The present study developed a cell-based high-throughput screen to identify small molecule inhibitors for NMO-IgG and AQP4 binding, and suggests a potential therapeutic value of isotetrandrine in NMO.

B Cells in the Multiple Sclerosis Central Nervous System: Trafficking and Contribution to CNS-Compartmentalized Inflammation

Clinical trial results of peripheral B cell depletion indicate abnormal proinflammatory B cell properties, and particularly antibody-independent functions, contribute to relapsing MS disease activity. However, potential roles of B cells in progressive forms of disease continue to be debated. Prior work indicates that presence of B cells is fostered within the inflamed MS central nervous system (CNS) environment, and that B cell-rich immune cell collections may be present within the meninges of patients. A potential association is reported between such meningeal immune cell collections and the subpial pattern of cortical injury that is now considered important in progressive disease. Elucidating the characteristics of B cells that populate the MS CNS, how they traffic into the CNS and how they may contribute to progressive forms of the disease has become of considerable interest. Here, we will review characteristics of human B cells identified within distinct CNS subcompartments of patients with MS, including the cerebrospinal fluid, parenchymal lesions, and meninges, as well as the relationship between B cell populations identified in these subcompartments and the periphery. We will further describe the different barriers of the CNS and the possible mechanisms of migration of B cells across these barriers. Finally, we will consider the range of human B cell responses (including potential for antibody production, cytokine secretion, and antigen presentation) that may contribute to propagating inflammation and injury cascades thought to underlie MS progression.

Plasma Exchange in a Patient with Tumefactive, Corticosteroid-Resistant Multiple Sclerosis

Tumefactive multiple sclerosis (MS) is an aggressive form of MS that can be difficult to treat with standard therapies. In severe MS relapses, plasma exchange (PLEX) has shown some benefit, but reports of its use in patients with tumefactive MS are limited. This article describes the successful use of PLEX in a patient with tumefactive MS. A 46-year-old right-handed woman with a recent diagnosis of MS presented with drowsiness, dysarthria, horizontal nystagmus, and quadriparesis. Her brain magnetic resonance images demonstrated multiple tumefactive demyelinating lesions in the medulla, bilateral periventricular white matter, and corona radiata white matter. She was initially treated with a 10-day course of intravenous methylprednisolone without benefit; therefore, PLEX was initiated. After the second exchange, the patient started to improve and was discharged initially to rehabilitation and then home. She was started on disease-modifying therapy with natalizumab and did not experience further relapses but had slow clinical decline during the next year, which led to discontinuation of natalizumab treatment. PLEX may be used as second-line treatment in corticosteroid-resistant MS relapses, but there are limited reports of its use in patients with tumefactive MS. This patient presented with aggressive disease with multiple tumefactive lesions and did not respond to standard treatment with corticosteroids. PLEX was successful in improving her symptoms, allowing her to return home, although the disease progressed during the next year.

Epidemiological, clinical, and immunological characteristics of neuromyelitis optica: A review

The aim of this study was to review the epidemiological and clinical characteristics of neuromyelitis optica (NMO) and the immunopathological mechanisms involved in the neuronal damage. NMO is an inflammatory demyelinating autoimmune disease of the central nervous system that most commonly affects the optic nerves and spinal cord. NMO is thought to be more prevalent among non-Caucasians and where multiple sclerosis (MS) prevalence is low. NMO follows a relapsing course in more than 80-90% of cases, which is more commonly in women. It is a complex disease with an interaction between host genetic and environmental factors and the main immunological feature is the presence of anti-aquaporin 4 (AQP4) antibodies in a subset of patients. NMO is frequently associated with multiple other autoantibodies and there is a strong association between NMO with other systemic autoimmune diseases. AQP4-IgG can cause antibody-dependent cellular cytotoxicity (ADCC) when effector cells are present and complement-dependent cytotoxicity (CDC) when complement is present. Acute therapies, including corticosteroids and plasma exchange, are designed to minimize injury and accelerate recovery. Several aspects of NMO pathogenesis remain unclear. More advances in the understanding of NMO disease mechanisms are needed in order to identify more specific biomarkers to NMO diagnosis.

Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients’ RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies.

Neuromyelitis optica: clinical features, immunopathogenesis and treatment

The term 'neuromyelitis optica' ('Devic's syndrome', NMO) refers to a syndrome characterized by optic neuritis and myelitis. In recent years, the condition has raised enormous interest among scientists and clinical neurologists, fuelled by the detection of a specific serum immunoglobulin (Ig)G reactivity (NMO-IgG) in up to 80% of patients with NMO. These autoantibodies were later shown to target aquaporin-4 (AQP4), the most abundant water channel in the central nervous system (CNS). Here we give an up-to-date overview of the clinical and paraclinical features, immunopathogenesis and treatment of NMO. We discuss the widening clinical spectrum of AQP4-related autoimmunity, the role of magnetic resonance imaging (MRI) and new diagnostic means such as optical coherence tomography in the diagnosis of NMO, the role of NMO-IgG, T cells and granulocytes in the pathophysiology of NMO, and outline prospects for new and emerging therapies for this rare, but often devastating condition.

Immunopathogenesis of neuromyelitis optica

Neuromyelitis optica (NMO, Devic's syndrome) is a clinical syndrome characterized by optic neuritis and (mostly longitudinally extensive) myelitis. If untreated, NMO usually takes a relapsing course and often results in blindness and tetra- or paraparesis. The discovery of autoantibodies to aquaporin-4, the most abundant water channel in the CNS, in 70-80% of patients with NMO (termed NMO-IgG or AQP4-Ab) and subsequent investigations into the pathogenic impact of this new reactivity have led to the recognition of NMO as an autoimmune condition and as a disease entity in its own right, distinct from classic multiple sclerosis. Here, we comprehensively review the current knowledge on the role of NMO-IgG/AQP4-Ab, B cells, T cells, and the innate immune system in the pathogenesis of NMO.

Optic neuritis

Acute optic neuritis is the most common optic neuropathy affecting young adults. Exciting developments have occurred over the past decade in understanding of optic neuritis pathophysiology, and these developments have been translated into treatment trials. In its typical form, optic neuritis presents as an inflammatory demyelinating disorder of the optic nerve, which can be associated with multiple sclerosis. Atypical forms of optic neuritis can occur, either in association with other inflammatory disorders or in isolation. Differential diagnosis includes various optic nerve and retinal disorders. Diagnostic investigations include MRI, visual evoked potentials, and CSF examination. Optical coherence tomography can show retinal axonal loss, which correlates with measures of persistent visual dysfunction. Treatment of typical forms with high-dose corticosteroids shortens the period of acute visual dysfunction but does not affect the final visual outcome. Atypical forms can necessitate prolonged immunosuppressive regimens. Optical coherence tomography and visual evoked potential measures are suitable for detection of neuroaxonal loss and myelin repair after optic neuritis. Clinical trials are underway to identify potential neuroprotective or remyelinating treatments for acutely symptomatic inflammatory demyelinating CNS lesions.

Immunotherapy of neuromyelitis optica

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that affects the optic nerves and spinal cord resulting in visual impairment and myelopathy. There is a growing body of evidence that immunotherapeutic agents targeting T and B cell functions, as well as active elimination of proinflammatory molecules from the peripheral blood circulation, can attenuate disease progression. In this review, we discuss the immunotherapeutic options and the treatment strategies in NMO. We also analyze the pathogenic mechanisms of the disease in order to provide recommendations regarding treatments.

[Therapeutic options for autoimmune encephalomyelitis]

Autoantibodies to neuronal tissue are becoming increasingly more important in the evaluation and classification of several neurological diseases, e.g. neuromyelitis optica, paraneoplastic syndromes of the central nervous system (CNS), stiff person syndrome or autoimmune epilepsy. As these disorders are rare, no evidence-based recommendations for therapy are available. Currently, immunomodulating or immunosuppressive drugs are administered in most cases. In paraneoplastic syndromes treatment of the underlying cancer is of considerable importance. This overview summarizes current experiences and recommendations in the treatment of autoimmune neurological disorders.

Optic neuritis in neuromyelitis optica

Neuromyelitis optica (NMO) is an autoimmune demyelinating disease associated with recurrent episodes of optic neuritis and transverse myelitis, often resulting in permanent blindness and/or paralysis. The discovery of autoantibodies (AQP4-IgG) that target aquaporin-4 (AQP4) has accelerated our understanding of the cellular mechanisms driving NMO pathogenesis. AQP4 is a bidirectional water channel expressed on the plasma membranes of astrocytes, retinal Müller cells, skeletal muscle, and some epithelial cells in kidney, lung and the gastrointestinal tract. AQP4 tetramers form regular supramolecular assemblies at the cell plasma membrane called orthogonal arrays of particles. The pathological features of NMO include perivascular deposition of immunoglobulin and activated complement, loss of astrocytic AQP4, inflammatory infiltration with granulocyte and macrophage accumulation, and demyelination with axon loss. Current evidence supports a causative role of AQP4-IgG in NMO, in which binding of AQP4-IgG to AQP4 orthogonal arrays on astrocytes initiates complement-dependent and antibody-dependent cell-mediated cytotoxicity and inflammation. Immunosuppression and plasma exchange are the mainstays of therapy for NMO optic neuritis. Novel therapeutics targeting specific steps in NMO pathogenesis are entering the development pipeline, including blockers of AQP4-IgG binding to AQP4 and inhibitors of granulocyte function. However, much work remains in understanding the unique susceptibility of the optic nerves in NMO, in developing animal models of NMO optic neuritis, and in improving therapies to preserve vision.