Questioning the existence of monophasic neuromyelitis optica spectrum disorder by defining a novel long-term relapse-free form from a large Chinese population.

OBJECTIVE: To clarify the existence of monophasic neuromyelitis optica spectrum disorders (NMOSD) and to identify predictive factors of long-term relapse-free form. METHODS: We retrospectively analyzed 289 Chinese patients with NMOSD. Selected subjects were divided into three groups based on the time interval between disease onset and the first relapse, if any. Clinical and imaging data were acquired from each patient's medical record and evaluated as predictive factors for NMOSD. RESULTS: In total, none of the participating patients exhibited a monophasic form of NMOSD. Rather, 241 patients were selected for relapse tendency analysis; 143 (59.3%) patients relapsed within the first year, 66 (27.4%) during 1-5 years, and 32 (13.3%) beyond 5 years. Such onset symptoms as optic neuritis (ON) and non-longitudinally extensive transverse myelitis (LETM) were independent prognostic factors for a prolonged remission interval (P < 0.05). The relapse rate was bi-modal for ON patients in the first year (47.9%) and beyond 5 years (24.0%) after disease onset, respectively. However, most TM and area postrema syndrome (APS) patients experienced an attack within the first year (61.3% for TM and 76.9% for APS). A survival analysis showed that attacks with APS (P < 0.0001) and TM (P < 0.05) have a significantly higher risk of early relapse than with ON and that seropositive aquaporin-4 antibody may shorten the relapse interval for all onset symptoms (P < 0.0001). CONCLUSIONS: Our study indicated that the monophasic form of NMOSD may not exist when a sufficient follow-up period is considered. Onset phenotypes with ON, non-APS, or non-LETM attacks had a lower risk of early relapse.

Antibody signatures in patients with histopathologically defined multiple sclerosis patterns.

Early active multiple sclerosis (MS) lesions can be classified histologically into three main immunopathological patterns of demyelination (patterns I-III), which suggest pathogenic heterogeneity and may predict therapy response. Patterns I and II show signs of immune-mediated demyelination, but only pattern II is associated with antibody/complement deposition. In pattern III lesions, which include Baló's concentric sclerosis, primary oligodendrocyte damage was proposed. Serum antibody reactivities could reflect disease pathogenesis and thus distinguish histopathologically defined MS patterns. We established a customized microarray with more than 700 peptides that represent human and viral antigens potentially relevant for inflammatory demyelinating CNS diseases, and tested sera from 66 patients (pattern I n = 12; II n = 29; III n = 25, including 8 with Baló's), healthy controls, patients with Sjögren's syndrome and stroke patients. Cell-based assays were performed for aquaporin 1 (AQP1) and AQP4 antibody detection. No single peptide showed differential binding among study cohorts. Because antibodies can react with different peptides from one protein, we also analyzed groups of peptides. Patients with pattern II showed significantly higher reactivities to Nogo-A peptides as compared to patterns I (p = 0.02) and III (p = 0.02). Pattern III patients showed higher reactivities to AQP1 (compared to pattern I p = 0.002, pattern II p = 0.001) and varicella zoster virus (VZV, compared to pattern II p = 0.05). In patients with Baló's, AQP1 reactivity was also significantly higher compared to patients without Baló's (p = 0.04), and the former revealed distinct antibody signatures. Histologically, Baló's patients showed loss of AQP1 and AQP4 in demyelinating lesions, but no antibodies binding conformational AQP1 or AQP4 were detected. In summary, higher reactivities to Nogo-A peptides in pattern II patients could be relevant for enhanced axonal repair and remyelination. Higher reactivities to AQP1 peptides in pattern III patients and its subgroup of Baló's patients possibly reflect astrocytic damage. Finally, latent VZV infection may cause peripheral immune activation.

Classifying the antibody-negative NMO syndromes: Clinical, imaging, and metabolomic modeling.

OBJECTIVE: To determine whether unsupervised principal component analysis (PCA) of comprehensive clinico-radiologic data can identify phenotypic subgroups within antibody-negative patients with overlapping features of multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSDs), and to validate the phenotypic classifications using high-resolution nuclear magnetic resonance (NMR) plasma metabolomics with inference to underlying pathologies. METHODS: Forty-one antibody-negative patients were recruited from the Oxford NMO Service. Thirty-six clinico-radiologic parameters, focusing on features known to distinguish NMOSD and MS, were collected to build an unbiased PCA model identifying phenotypic subgroups within antibody-negative patients. Metabolomics data from patients with relapsing-remitting MS (RRMS) (n = 34) and antibody-positive NMOSD (Ab-NMOSD) (aquaporin-4 antibody n = 54, myelin oligodendrocyte glycoprotein antibody n = 20) were used to identify discriminatory plasma metabolites separating RRMS and Ab-NMOSD. RESULTS: PCA of the 36 clinico-radiologic parameters revealed 3 phenotypic subgroups within antibody-negative patients: an MS-like subgroup, an NMOSD-like subgroup, and a low brain lesion subgroup. Supervised multivariate analysis of metabolomics data from patients with RRMS and Ab-NMOSD identified myoinositol and formate as the most discriminatory metabolites (both higher in RRMS). Within antibody-negative patients, myoinositol and formate were significantly higher in the MS-like vs NMOSD-like subgroup; myoinositol (mean [SD], 0.0023 [0.0002] vs 0.0019 [0.0003] arbitrary units [AU]; p = 0.041); formate (0.0027 [0.0006] vs 0.0019 [0.0006] AU; p = 0.010) (AU). CONCLUSIONS: PCA identifies 3 phenotypic subgroups within antibody-negative patients and that the metabolite discriminators of RRMS and Ab-NMOSD suggest that these groupings have some pathogenic meaning. Thus, the identified clinico-radiologic discriminators may provide useful diagnostic clues when seeing antibody-negative patients in the clinic.

Neuromyelitis optica spectrum disorders: Features of aquaporin-4, myelin oligodendrocyte glycoprotein and double-seronegative-mediated subtypes.

The new diagnostic classification of neuromyelitis optica spectrum disorder (NMOSD) in 2015 highlights the central role of biomarkers, such as antibodies against aquaporin-4 (AQP4-Ab), in diagnosis. Also, in approximately 20-25% of patients without AQP4-Ab (NMOSDAQP4-) the presence of an antibody directed against myelin oligodendrocyte glycoprotein (MOG) characterizes a specific population of NMOSD patients (NMOSDMOG+), according to their demographic and clinical data and prognoses. While double-seronegative cases (NMOSDNEG) have not been fully described, they may correspond to the very first patients with opticospinal demyelination reported by Devic and Gault in 1894. The present report reviews the current knowledge of the pathophysiology and clinical features of NMOSDAQP4+, NMOSDMOG+ and NMOSDNEG patients, and also discusses the relationship between the extended spectrum of MOG disease and NMOSDMOG+. Finally, the current treatments for acute relapses and relapse prevention are described, with a focus on serological-based therapeutic responses and the promising new therapeutic targets.

Early relapse after RTX initiation in a patient with NMO/MS overlap syndrome: How long to conclude to a failure treatment?

BACKGROUND: We report a dramatic clinical and radiological worsening within two months after rituximab initiation in a patient with NeuroMyelitis Optica/Multiple Sclerosis (NMO/MS) overlap syndrome. METHODS: Case study. RESULTS: A 45-year-old Caucasian woman with NMO/MS overlap syndrome experienced a severe myelitis nine weeks after first rituximab infusion, with extensive new gadolinium-enhanced spinal cord lesions. CONCLUSION: This case report illustrates the limits of MS and NMO-Spectrum Disorder classification and challenges the criteria of therapeutic failure within the 6 months after rituximab initiation.

Comparación de los espectros de neuromielitis óptica según el seroestado del anticuerpo AQP4 en un centro de referencia mexicano / Comparison of neuromyelitis optica spectra according to AQP4 antibody serostatus in a Mexican referral centre

Introducción. Estudios recientes describen que los pacientes con neuromielitis óptica (NMO) o trastornos del espectro de NMO seronegativos exhiben características clínicas diferentes a los pacientes seropositivos al anticuerpo acuaporina-4 (AQP4). Objetivo. Analizar las características clínicas y paraclínicas de pacientes con NMO según el estado sérico del anticuerpo AQP4. Pacientes y métodos. Estudio retrospectivo de 100 pacientes con NMO que cumplían los criterios de Wingerchuk: 70 presentaron positividad al anticuerpo AQP4 y 30 fueron seronegativos. Resultados. Un 70% de los sujetos cumplió los criterios para la NMO, y un 30%, para los trastornos del espectro de NMO. Los pacientes seropositivos presentaron mayor discapacidad en las puntuaciones de la escala de la Asociación Americana de Lesión de la Medula Espinal (ASIA) y la escala ampliada del estado de discapacidad (p = 0,034 y 0,004, respectivamente) comparados con los seronegativos durante el seguimiento; en este mismo grupo hubo mayor afectación visual (p = 0,02), mayor número de recaídas (p = 0,008) y mayor número de segmentos medulares afectados (p = 0,003). Conclusión. Este estudio proporciona una visión general de las características clínicas y paraclínicas de los pacientes con NMO según el seroestado del anticuerpo AQP4. Los pacientes seropositivos al anticuerpo AQP4 presentan mayor afectación clínica e imaginológica (AU)

Introduction. Recent studies report that patients with neuromyelitis optica (NMO) or seropositive NMO spectra disorders display clinical characteristics that are different from those of patients who are seropositive for the aquaporin-4 (AQP4) antibody. Aim. To analyse the clinical and paraclinical characteristics of patients with NMO according to their serum AQP4 status. Patients and methods. We conducted a retrospective study of 100 patients with NMO who fulfilled the Wingerchuk criteria: 70 were positive for the AQP4 antibody and 30 were seronegative. Results. 70% of the subjects met the criteria for NMO, and 30% met criteria for NMO spectra disorders. The seropositive patients presented greater disability in the scores on the American Spinal Injury Association scale (ASIA) and the Expanded Disability Status Scale (p = 0.034 and 0.004, respectively) compared to seronegatives during the follow-up; in this same group there was greater visual involvement (p = 0.02), a higher number of relapses (p = 0.008) and a greater number of spinal segments involved (p = 0.003). Conclusion. This study provides an overview of the clinical and paraclinical characteristics of patients with NMO according to the AQP4 antibody serostatus. Patients who are seropositive for the AQP4 antibody present greater clinical and imaging Involvement (AU)

Gray matter MRI differentiates neuromyelitis optica from multiple sclerosis using random forest.

OBJECTIVE: We tested whether brain gray matter (GM) imaging measures can differentiate between multiple sclerosis (MS) and neuromyelitis optica (NMO) using random-forest classification. METHODS: Ninety participants (25 patients with MS, 30 patients with NMO, and 35 healthy controls [HCs]) were studied in Tehran, Iran, and 54 (24 patients with MS, 20 patients with NMO, and 10 HCs) in Padua, Italy. Participants underwent brain T1 and T2/fluid-attenuated inversion recovery MRI. Volume, thickness, and surface of 50 cortical GM regions and volumes of the deep GM nuclei were calculated and used to construct 3 random-forest models to classify patients as either NMO or MS, and separate each patient group from HCs. Clinical diagnosis was the gold standard against which the accuracy was calculated. RESULTS: The classifier distinguished patients with MS, who showed greater atrophy especially in deep GM, from those with NMO with an average accuracy of 74% (sensitivity/specificity: 77/72; p < 0.01). When we used thalamic volume (the most discriminating GM measure) together with the white matter lesion volume, the accuracy of the classification of MS vs NMO was 80%. The classifications of MS vs HCs and NMO vs HCs achieved higher accuracies (92% and 88%). CONCLUSIONS: GM imaging biomarkers, automatically obtained from clinical scans, can be used to distinguish NMO from MS, even in a 2-center setting, and may facilitate the differential diagnosis in clinical practice. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that GM imaging biomarkers can distinguish patients with NMO from those with MS.

A Novel Approach to Discriminate Subgroups in Multiple Sclerosis.

Multiple sclerosis (MS) is an autoimmune disease of central nervous system. Since different types of immune cells are involved in MS pathogenesis, in this study we aimed to evaluate serum levels of several immunological components including soluble CD4 (sCD4), sCD8, sCD163, and immunoglobulins as markers of activity of T-cells, macrophages, and B-cells in different types of MS. Serum levels of sCD4, sCD8, and sCD163 of patients with relapsing-remitting MS (RRMS, n=61), primary progressive MS (PRMS, n=31), secondary progressive MS (SPMS, n=31), clinical isolated syndrome (CIS, n=31) and neuromyelitis optica (NMO, n=31), and healthy controls (n=49) were measured using enzyme-linked immunosorbent assay (ELISA). Serum levels of Ig-G, Ig-M, and Ig-A were determined using nephelometric technique. Serum levels of sCD4, sCD8, sCD163, Ig-G, Ig-M, and Ig-A were significantly different in five groups of cases (p<0.05). Furthermore, application of stepwise method of discriminant analysis yielded 4 significant discriminant functions of classification due to the presence of six levels of categorical variables in the analysis. The most important function explained 85.5% of the total variance with the correlation value of 0.79. Taken together, our preliminary analysis suggests that although we found some functions to discriminate most of the patients, further studies will be required to individuate immunological markers characterizing the different type of MS including RRMS, PPMS, SPMS, CIS and NMO as proved by the data on sCD4, sCD163, Ig-M, and Ig-G in blood.

Neuromyelitis optica: a positive appraisal of seronegative cases.

Neuromyelitis optica (NMO) is a rare inflammatory disorder of the central nervous system. The hallmark of NMO is the presence of specific autoantibodies directed against aquaporin 4 (AQP4-IgG). AQP4-IgG, included in diagnostic criteria, has enlarged the clinical spectrum of NMO and serves to predict relapses. Moreover AQP4-IgG has provided unprecedented insight in the immunopathology of NMO, representing a rationale for therapeutic intervention with relevant novel treatment strategies specific for NMO. However, some patients remain seronegative for AQP4-IgG despite a definite diagnosis of NMO and the use of the finest methods for antibody detection. Interestingly, seronegative NMO (NMO(neg)) patients exhibit different demographic and disease-related characteristics in comparison to seropositive patients. The recent association with autoantibodies specific for myelin oligodendrocyte glycoprotein (MOG) is the main indication that disease mechanisms might differ in NMO(pos) and NMO(neg), challenging the position of NMO(neg) patients in the spectrum of demyelinating diseases and therapeutic strategies to be adopted. Thus, a reappraisal of the NMO(neg) population is needed to improve NMO care. Here the current knowledge regarding NMO(neg) is reviewed and hypotheses on its pathogenesis are made including a comprehensive description of detection methods and the prevalence of AQP4-IgG and a review of the epidemiological, clinical and paraclinical characteristics of NMO(neg); finally an integrated view of the general pathophysiological mechanisms underlying NMO(neg) is provided.

Aquaporin 4 IgG serostatus and outcome in recurrent longitudinally extensive transverse myelitis.

IMPORTANCE: Studies focused on recurrent longitudinally extensive transverse myelitis (rLETM) are lacking. OBJECTIVES: To determine the aquaporin 4 (AQP4) IgG detection rate using recombinant human APQ4-based assays in sequential serum specimens collected from patients with rLETM categorized as negative by first-generation tissue-based indirect immunofluorescence (IIF) assay and to define the clinical characteristics and motor disability outcomes in AQP4-IgG-positive rLETM. DESIGN, SETTING, AND PARTICIPANTS: A search of the Mayo Clinic computerized central diagnostic index (October 1, 2005, through November 30, 2011), cross-linked with the Neuroimmunology Laboratory database, identified 48 patients with rLETM, of whom 36 (75%) were positive and 12 (25%) negative for neuromyelitis optica (NMO) IgG (per IIF of serial serum specimens). Stored serum specimens from "seronegative" patients were retested with recombinant human AQP4-based assays, including enzyme-linked immunosorbent, transfected cell-based, and fluorescence-activated cell-sorting assays. Control patients included 140 AQP4-IgG-positive patients with NMO, of whom a subgroup of 20 initially presented with 2 attacks of transverse myelitis (rLETM-onset NMO). MAIN OUTCOMES AND MEASURES: AQP4-IgG serostatus, clinical characteristics, and Expanded Disability Status Scale score. RESULTS: Six patients with negative IIF results were reclassified as AQP4-IgG positive, yielding an overall AQP4-IgG seropositivity rate of 89%. Fluorescence-activated cell-sorting, cell-based, and enzyme-linked immunosorbent assays improved the detection rate to 89%, 85%, and 81%, respectively. The female to male ratio was 2:3 for AQP4-IgG-negative rLETM and 5:1 for AQP4-IgG-positive patients. The AQP4-IgG-positive patients with rLETM or rLETM-onset NMO were similar in age at onset, sex ratio, attack severity, relapse rate, and motor disability. From Kaplan-Meier analyses, 36% of AQP4-IgG-positive patients with rLETM are anticipated to need a cane to walk within 5 years after onset. For patients with rLETM-onset NMO, the median time from onset to first optic neuritis attack (54 months) was similar to the median disease duration for AQP4-IgG-positive patients with rLETM (59 months). The median number of attacks was 3 for AQP4-IgG-positive patients with rLETM (range, 2-22), and the first optic neuritis attack for those with rLETM-onset NMO followed a median of 3 myelitis attacks (range, 2-19). Immunosuppressant therapy reduced the relapse rate in both AQP4-IgG-positive and AQP4-IgG-negative patients with rLETM. CONCLUSIONS AND RELEVANCE: Recombinant antigen-based assays significantly increase AQP4-IgG detection in patients with rLETM, and AQP4-IgG-negative adults with rLETM are rare. Evolution to NMO can be anticipated in AQP4-IgG-positive patients. Early initiation of immunotherapy may result in a more favorable motor outcome.

[Neuromyelitis optica is a frequently seen inflammatory demyelinating disease]. / Neuromyelitis optica er en hyppig inflammatorisk demyelinerende sygdom.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system with autoimmune characteristics. Serum immunoglobulin G autoantibodies have been identified in the majority of NMO patients with the water channel aquaporin-4 (AQP4) as their main target autoantigen. Clinical criteria have defined NMO and NMO-spectrum disease. The clinical features include inflammation of the optic nerve.

Immune-mediated CNS diseases: a review on nosological classification and clinical features.

The immune-mediated diseases of the central nervous system (CNS) cover a wide range of clinical manifestations. Over the last years, considerable efforts have been made to establish a nosologic concept based upon distinctive pathophysiological characteristics of the single diseases. We describe the historically defined entities of immune-mediated diseases that primarily, but not exclusively, are affecting myelin structures. These include very rare entities as Schilder's, Balo's and Marburg's disease or the chronic and relapsing types of optic neuritis, for which evidence based paradigms still are virtually missing. In other, slightly more frequent diseases as neuromyelitis optica (NMO), advances in the concepts of specific biological features have been achieved and are beginning to transform into changes in clinical concepts. Acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) are by far the most frequent entities in this group and thus the only ones for which extensive empirical data on disease biology and evidence based clinical management strategies exist by now. For the most important entities, clinical features and therapeutic approaches are reviewed on the basis of current evidence. The results of basic science studies are assessed for their implications in nosological classification.

Brain involvement in neuromyelitis optica spectrum disorders.

BACKGROUND: Neuromyelitis optica spectrum disorders (NMOSDs) are severe inflammatory demyelinating disorders of the central nervous system. Brain involvement is increasingly recognized. OBJECTIVE: To study brain involvement in NMOSDs among Hong Kong Chinese patients. DESIGN: Retrospective study of patients with NMOSDs. SETTING: Tertiary medical center in Hong Kong. Patients  Thirty-four Hong Kong Chinese patients with NMOSDs of 2 years or longer were recruited. INTERVENTIONS: Brain and spinal cord magnetic resonance imaging was performed during NMOSD attacks and was repeated yearly for the first 3 years. MAIN OUTCOME MEASURES: We evaluated clinical features of NMOSDs associated with brain involvement and brain lesions on magnetic resonance imaging. RESULTS: Among 34 patients with NMOSDs of 2 years or longer, 20 (59%) had brain involvement. The mean age at onset among these 20 patients was 45.6 years (age range, 19-67 years); 18 were women. Eleven patients (32% of all the patients with NMOSDs) had clinical manifestation of brain involvement, 19 patients (56%) had brain abnormalities on magnetic resonance imaging consistent with inflammatory demyelination, and 2 patients (6%) fulfilled criteria for multiple sclerosis. Clinical manifestation of brain involvement included the following: trigeminal neuralgia; vomiting, vertigo, ataxia, dysphagia, and tetraparesis from lesions around the third and fourth ventricles and aqueduct; homonymous hemianopia, aphasia, hemiparesis, and cognitive impairment from extensive hemispheric white matter lesions; and ataxia, diplopia, hiccups, facial sensory loss, internuclear ophthalmoplegia, hemisensory loss, and hemiparesis from other lesions in the midbrain, pons, cerebellar peduncles, and medulla. Eight patients (24%) developed brainstem encephalitis clinically, and brainstem encephalitis was the initial clinical manifestation in 6 patients (18%). Brain abnormalities on magnetic resonance imaging were detected in brainstem in 15 patients (44%), hemispheric periventricular white matter in 7 patients (21%), deep white matter in 7 patients (21%), corpus callosum in 4 patients (12%), subcortical white matter in 3 patients (9%), thalamus in 2 patients (6%), hypothalamus in 1 patient (3%), basal ganglia in 1 patient (3%), internal capsule in 1 patient (3%), periaqueductal gray matter in 1 patient (3%), and around the third and fourth ventricles in 1 patient (3%); large confluent lesions were detected in 2 patients (6%). CONCLUSION: Brain involvement manifesting clinically as brainstem encephalitis is common among Hong Kong Chinese patients with NMOSDs.

[A concept of neuromyelitis optica in Japan].

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterized by relapses of optic neuritis and acute myelitis. The disease was referred to as the optic-spinal form of multiple sclerosis (OSMS) in Japan for a long period. A specific auto-antibody, NMO-IgG, was detected in the serum of NMO patients, and aquaporin-4 water channel protein was detected as its target antigen; aquaporin-4 water channel protein is localized at the end-feet of astrocytes. Because of the presence of this specific serum auto-antibody, most OSMS patients in Japan were found to exhibit a disease that was identical to NMO that affects individuals of the Western countries. Since the discovery of NMO-IgG, various clinical and histopathological features of this condition have been recognized; in addition the concept of NMO has been established in Japan as well as in many other countries.

Patterns of antibody binding to aquaporin-4 isoforms in neuromyelitis optica.

BACKGROUND: Neuromyelitis optica (NMO), a severe demyelinating disease, represents itself with optic neuritis and longitudinally extensive transverse myelitis. Serum NMO-IgG autoantibodies (Abs), a specific finding in NMO patients, target the water channel protein aquaporin-4 (AQP4), which is expressed as a long (M-1) or a short (M-23) isoform. METHODOLOGY/PRINCIPAL FINDINGS: The aim of this study was to analyze serum samples from patients with NMO and controls for the presence and epitope specificity of IgG and IgM anti-AQP4 Abs using an immunofluorescence assay with HEK293 cells expressing M-1 or M-23 human AQP4. We included 56 patients with definite NMO (n = 30) and high risk NMO (n = 26), 101 patients with multiple sclerosis, 27 patients with clinically isolated syndromes (CIS), 30 patients with systemic lupus erythematosus (SLE) or Sjögren's syndrome, 29 patients with other neurological diseases and 47 healthy controls. Serum anti-AQP4 M-23 IgG Abs were specifically detected in 29 NMO patients, 17 patients with high risk NMO and two patients with myelitis due to demyelination (CIS) and SLE. In contrast, IgM anti-AQP4 Abs were not only found in some NMO and high risk patients, but also in controls. The sensitivity of the M-23 AQP4 IgG assay was 97% for NMO and 65% for high risk NMO, with a specificity of 100% compared to the controls. Sensitivity with M-1 AQP4 transfected cells was lower for NMO (70%) and high risk NMO (39%). The conformational epitopes of M-23 AQP4 are the primary targets of NMO-IgG Abs, whereas M-1 AQP4 Abs are developed with increasing disease duration and number of relapses. CONCLUSIONS: Our results confirm M-23 AQP4-IgG Abs as reliable biomarkers in patients with NMO and high risk syndromes. M-1 and M-23 AQP4-IgG Abs are significantly associated with a higher number of relapses and longer disease duration.