Neuromyelitis optica-IgG (aquaporin-4) autoantibodies in immune mediated optic neuritis

MOG antibody-associated optic neuritis

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a demyelinating disorder, distinct from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). MOGAD most frequently presents with optic neuritis (MOG-ON), often with characteristic clinical and radiological features. Bilateral involvement, disc swelling clinically and radiologically, and longitudinally extensive optic nerve hyperintensity with associated optic perineuritis on MRI are key characteristics that can help distinguish MOG-ON from optic neuritis due to other aetiologies. The detection of serum MOG immunoglobulin G utilising a live cell-based assay in a patient with a compatible clinical phenotype is highly specific for the diagnosis of MOGAD. This review will highlight the key clinical and radiological features which expedite diagnosis, as well as ancillary investigations such as visual fields, visual evoked potentials and cerebrospinal fluid analysis, which may be less discriminatory. Optical coherence tomography can identify optic nerve swelling acutely, and atrophy chronically, and may transpire to have utility as a diagnostic and prognostic biomarker. MOG-ON appears to be largely responsive to corticosteroids, which are often the mainstay of acute management. However, relapses are common in patients in whom follow-up is prolonged, often in the context of early or rapid corticosteroid tapering. Establishing optimal acute therapy, the role of maintenance steroid-sparing immunotherapy for long-term relapse prevention, and identifying predictors of relapsing disease remain key research priorities in MOG-ON.

Can volumetric analysis of the brain help diagnose isolated optic neuritis?

Isolated optic neuritis is a single episode inflammatory optic neuropathy. This condition, which affects the optimal function of the optic nerve, is not associated with neurological or systemic diseases. Our study aimed to compare patients with isolated optic neuritis and normal healthy individuals in terms of the cerebrum, cerebellum and hippocampus volumes by using the "volBrain Online MRI Brain Volumetry System" program. Persons diagnosed with isolated optic neuritis (n = 16) and persons without any disease (n = 16) were included in the study. VolBrain was used to process the MRI data and, the findings were compared with Mann-Whitney U test. Values with a p-value <0.05 were considered statistically significant. The cerebrum white matter volumes in the total brain and in the right-left hemispheres of the brain were statistically significantly lower in the optic neuritis group (p = 0.029; p = 0.050; p = 0.029, respectively). In the segmental cerebellum analysis, the left side lobule VIIIB, the total and right-left side lobule IX volumes were statistically significantly higher (p = 0.022; p = 0.014; p = 0.029; p = 0.018, respectively). In total, lobule I-II volume was statistically significantly lower in the optic neuritis group (p = 0.046). In the segmental hippocampus analysis, the right side CA2-CA3, the total and right-left side SR-SL-SM volumes were statistically significantly lower in the optic neuritis group (p = 0.039; p = 0.050; p = 0.016, respectively). There are neurodegenerative changes in brain volume in patients with isolated optic neuritis. Although volBrain alone is not sufficient to diagnose isolated optic neuritis, it provides quantitative data that can be used as a complementary diagnostic method.

An update on optic neuritis

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

Acute optic neuritis: What are the clues to the aetiological diagnosis in real life?

BACKGROUND

Previous cross-sectional studies have reported distinct clinical and radiological features among the different acute optic neuritis (ON) aetiologies. Nevertheless, these reports often included the same number of patients in each group, not taking into account the disparity in frequencies of ON aetiologies in a real-life setting and thus, it remains unclear what are the truly useful features for distinguishing the different ON causes. To determine whether clinical evaluation, ophthalmological assessment including the optical coherence tomography (OCT), CSF analysis, and MRI imaging may help to discriminate the different causes of acute ON in a real-life cohort.

METHODS

In this prospective monocentric study, adult patients with recent acute ON (<1 month) underwent evaluation at baseline and 1 and 12 months, including, high- and low-contrast visual acuity, visual field assessment and OCT measurements, baseline CSF analysis and MRI.

RESULTS

Among 108 patients, 71 (65.7%) had multiple sclerosis (MS), 19 (17.6%) had idiopathic ON, 13 (12.0%) and 5 (4.6%) had myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies, at last follow up respectively.At baseline, the distribution of bilateral ON, CSF-restricted oligoclonal bands, optic perineuritis, optic nerve length lesions and positive dissemination in space and dissemination in time criteria on MRI were significantly different between the four groups (p <0.001). No significant difference in visual acuity nor inner retinal layer thickness was found between the different ON aetiologies.

CONCLUSIONS

In this large prospective study, bilateral visual involvement, CSF and MRI results are the most useful clues in distinguishing the different aetiologies of acute ON, whereas ophthalmological assessments including OCT measurements revealed no significant difference between the aetiologies.

Diagnostic value of intereye difference metrics for optic neuritis in aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorders

BACKGROUND

The novel optic neuritis (ON) diagnostic criteria include intereye differences (IED) of optical coherence tomography (OCT) parameters. IED has proven valuable for ON diagnosis in multiple sclerosis but has not been evaluated in aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorders (AQP4+NMOSD). We evaluated the diagnostic accuracy of intereye absolute (IEAD) and percentage difference (IEPD) in AQP4+NMOSD after unilateral ON >6 months before OCT as compared with healthy controls (HC).

METHODS

Twenty-eight AQP4+NMOSD after unilateral ON (NMOSD-ON), 62 HC and 45 AQP4+NMOSD without ON history (NMOSD-NON) were recruited by 13 centres as part of the international Collaborative Retrospective Study on retinal OCT in Neuromyelitis Optica study. Mean thickness of peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell and inner plexiform layer (GCIPL) were quantified by Spectralis spectral domain OCT. Threshold values of the ON diagnostic criteria (pRNFL: IEAD 5 µm, IEPD 5%; GCIPL: IEAD: 4 µm, IEPD: 4%) were evaluated using receiver operating characteristics and area under the curve (AUC) metrics.

RESULTS

The discriminative power was high for NMOSD-ON versus HC for IEAD (pRNFL: AUC 0.95, specificity 82%, sensitivity 86%; GCIPL: AUC 0.93, specificity 98%, sensitivity 75%) and IEPD (pRNFL: AUC 0.96, specificity 87%, sensitivity 89%; GCIPL: AUC 0.94, specificity 96%, sensitivity 82%). The discriminative power was high/moderate for NMOSD-ON versus NMOSD-NON for IEAD (pRNFL: AUC 0.92, specificity 77%, sensitivity 86%; GCIP: AUC 0.87, specificity 85%, sensitivity 75%) and for IEPD (pRNFL: AUC 0.94, specificity 82%, sensitivity 89%; GCIP: AUC 0.88, specificity 82%, sensitivity 82%).

CONCLUSIONS

Results support the validation of the IED metrics as OCT parameters of the novel diagnostic ON criteria in AQP4+NMOSD.

The Role of Aquaporin 5 (AQP5) in Lung Adenocarcinoma: A Review Article

Aquaporins (AQPs) are selective, transmembrane proteins, which are primarily responsible for the transport of water and small molecules. They have been demonstrated to play a key role in the development and progression of cancer. Lung adenocarcinoma is the most common primary lung cancer diagnosed in patients in Europe and the USA. The research done so far has provided firm evidence that some AQPs can be biomarkers for various diseases. The objective of this review article is to present a potential role of AQP5 in the development of lung adenocarcinoma. Original papers discussing the involvement of AQP5 in carcinogenesis and containing relevant clinical data were identified. In order to analyze the research material in accordance with PRISMA guidelines, a systematic search of the ScienceDirect, Web of Science, and Pubmed databases was conducted. Out of the total number of 199 papers identified, 14 original articles were subject to analysis. This article presents the pathophysiological role of AQP5 in the biology of lung adenocarcinoma as well as its prognostic value. The analysis substantiates the conclusion that the prognostic value of AQP5 in lung cancer requires further research. Another aim of this paper is to disseminate knowledge about AQPs among clinicians.

Neuromyelitis optica spectrum disorder: pathophysiological approach

Aim: To review the main pathological findings of Neuromyelitis Optica Spectrum Disorder (NMOSD) associated with the presence of autoantibodies to aquaporin-4 (AQP4) as well as the mechanisms of astrocyte dysfunction and demyelination. Methods: An comprehensive search of the literature in the field was carried out using the database of The National Center for Biotechnology Information from . Systematic searches were performed until July 2022. Results: NMOSD is an inflammatory and demyelinating disease of the central nervous system mainly in the areas of the optic nerves and spinal cord, thus explaining mostly the clinical findings. Other areas affected in NMOSD are the brainstem, hypothalamus, and periventricular regions. Relapses in NMOSD are generally severe and patients only partially recover. NMOSD includes clinical conditions where autoantibodies to aquaporin-4 (AQP4-IgG) of astrocytes are detected as well as similar clinical conditions where such antibodies are not detected. AQP4 are channel-forming integral membrane proteins of which AQ4 isoforms are able to aggregate in supramolecular assemblies termed orthogonal arrays of particles (OAP) and are essential in the regulation of water homeostasis and the adequate modulation of neuronal activity and circuitry. AQP4 assembly in orthogonal arrays of particles is essential for AQP4-IgG pathogenicity since AQP4 autoantibodies bind to OAPs with higher affinity than for AQP4 tetramers. NMOSD has a complex background with prominent roles for genes encoding cytokines and cytokine receptors. AQP4 autoantibodies activate the complement-mediated inflammatory demyelination and the ensuing damage to AQP4 water channels, leading to water influx, necrosis and axonal loss. Conclusions: NMOSD as an astrocytopathy is a nosological entity different from multiple sclerosis with its own serological marker: immunoglobulin G-type autoantibodies against the AQP4 protein which elicits a complement-dependent cytotoxicity and neuroinflammation. Some patients with typical manifestations of NMSOD are AQP4 seronegative and myelin oligodendrocyte glycoprotein positive. Thus, the detection of autoantibodies against AQP4 or other autoantibodies is crucial for the correct treatment of the disease and immunosuppressant therapy is the first choice.

Should Aquaporin-4 Antibody Test Be Performed in all Patients With Isolated Optic Neuritis?

BACKGROUND

Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients.

METHODS

We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients.

RESULTS

Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up.

CONCLUSION

Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.

Disease course of Chronic Relapsing Inflammatory Optic Neuropathy (CRION) in a single care center

BACKGROUND

Chronic relapsing inflammatory optic neuropathy (CRION) is a recurrent, idiopathic optic neuritis and is considered as a rare disease.

OBJECTIVE

To describe the clinical course during long-term follow-up of patients with a diagnosis of CRION.

METHODS

From a cohort of 1,735 patients with demyelinating disorders, we selected patients aged over 16 years with CRION according to current criteria. Demographic and clinical data, including initial presentation, symptoms, number of relapses, time delay in diagnosis, diagnostic methods, and treatment were obtained from clinical files. Infections, autoimmune diseases, and multiple sclerosis, among other conditions, were ruled out in all patients.

RESULTS

We analyzed 30 patients with CRION: 24 women and six men, with mean age of 42.8±10.2 years, median disease course of 7.9 years (5.29-13.1), and median number of attacks of 2 (IQR 2-4). The initial manifestation was ocular pain in 97% and bilateral and sequential affection in 87%. Visual acuity was recovered in 50%, did not improve in 33%, and recovered incompletely in 17%. Antibodies against aquaporin-4 (AQP4-Abs) were negative in 73.3%. Magnetic resonance imaging of the brain was normal in 76.7%. None of the patients evolved to another demyelinating disease over time. Initial treatment was methylprednisolone in 100%, and plasmapheresis in 20%. Currently, all patients are on maintenance treatment with mycophenolate mofetil or rituximab with a decrease in relapsing rate.

CONCLUSIONS

Diagnosis of CRION is challenging and should be kept in mind. Prompt diagnosis, adequate treatment and close follow-up are essential to prevent disabling sequelae in these patients.

Clinico-epidemiologic characteristics of optic neuritis in a tertiary eye centre in Eastern India based on the status of serum aquaporin-4 antibody

Purpose:

To elucidate the clinico-epidemiologic characteristics of optic neuritis based on the status of serum aquaporin-4 antibody (AQP4-Ab) in patients with optic neuritis (ON).

Methods:

Medical records of 106 patients with ON and a follow-up of 3 years were reviewed. For each patient, the following data were extracted: medical history, findings of the ocular examination, brain, orbital or spinal MRI, and serological tests for AQP4. The ON was classified as typical or atypical based on disc examination and improvement in vision after intravenous methylprednisolone (IVMP). The clinical findings (typical or atypical), disease course, and outcomes were analyzed according to the serostatus of the ON.

Results:

10 patients ((9.4%) were seropositive for AQP4-Ab; all had atypical ON. 96 patients (91%) were seronegative for AQP4-Ab: 36 atypical ON and 60 typical ON. Profound visual impairment at presentation was seen in all patients. However, at the end of the study period, seropositive and seronegative atypical ON had poor visual outcomes as compared to seronegative typical ON (P = 0.002). Five seropositive and four seronegative patients with atypical ON developed transverse myelitis. Bilateral disease with relapse was more in seropositive patients (80%); however, seronegative with atypical ON also had bilateral presentation and relapse in 42% and 41%, respectively.

Conclusion:

AQP4-Ab seropositive patients mostly present with atypical features such as bilateral recurrent ON, poor visual outcome, and increased incidence of transverse myelitis. However, atypical clinical features can also be seen in seronegative ON with a poor visual outcome and a recalcitrant course.

Chronic Relapsing Inflammatory Optic Neuropathy (CRION)

Purpose of review

This review highlights the epidemiology, clinical and radiologic characteristics of chronic relapsing inflammatory optic neuropathy (CRION) and treatment modalities.

Recent findings

Summary

CRION is an inflammatory optic neuropathy that is characterized by a chronic and relapsing course, that is characterized by pain associated with subacute vision loss. It is favorably responsive but highly dependent on corticosteroids with frequent relapses in the setting of steroid tapering. Additional diagnostic biomarkers and further studies are required to better diagnose and treat this rare but potentially debilitating condition.

Optic neuritis classification in 2021

Optic neuritis (ON) can be associated with inflammatory disease of the central nervous system or can be isolated, with or without relapse. It can also be associated with infectious or systemic disease. These multiple associations based on a variety of clinical, radiological, and biological criteria that have changed over time have led to overlapping phenotypes: a single ON case can be classified in several ways simultaneously or over time. As early, intensive treatment is often required, its diagnosis should be rapid and precise. In this review, we present the current state of knowledge about diagnostic criteria for ON aetiologies in adults and children, we discuss overlapping phenotypes, and we propose a homogeneous classification scheme. Even if distinctions between typical and atypical ON are relevant, their phenotypes are largely overlapping, and clinical criteria are neither sensitive enough, nor specific enough, to assure a diagnosis. For initial cases of ON, clinicians should perform contrast enhanced MRI of the brain and orbits, cerebral spinal fluid analysis, and biological analyses to exclude secondary infectious or inflammatory ON. Systematic screening for MOG-IgG and AQP4-IgG IgG is recommended in children but is still a matter of debate in adults. Early recognition of neuromyelitis optica spectrum disorder, MOG-IgG-associated disorder, and chronic relapsing idiopathic optic neuritis is required, as these diagnoses require therapies for relapse prevention that are different from those used to treat multiple sclerosis.

Complement testing in the clinical laboratory

The complement system is the human's first line of defense against microbial pathogens because of its important housekeeping and infection/inflammation roles. It is composed of a series of soluble and cell-bound proteins that are activated in a cascade effect, similar to the coagulation pathways. There are different pattern recognizing molecules that activate the complement system in response to stimuli or threats, acting through three initiation pathways: classical, lectin, and alternative. All three activation pathways converge at the C3 component and share the terminal pathway. The main outputs of the complement system action are lytic killing of microbes, the release of pro-inflammatory anaphylatoxins, and opsonization of targets. Laboratory testing is relevant in the setting of suspected complement deficiencies, as well as in the emerging number of diseases related to dysregulation (over-activation) of complement. Most common assays measure complement lytic activity and the different complement component concentrations. Specialized testing includes the evaluation of autoantibodies against complement components, activation fragments, and genetic studies. In this review, we cover laboratory testing for complement and the conditions with complement involvement, as well as current challenges in the field.

Prognostic Factors for Visual Outcomes Following the First Episode of NMOSD-Related Optic Neuritis in Affected Eyes

OBJECTIVE

We aim to identify prognostic factors for visual outcomes following a first episode of neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) in affected eyes.

MATERIALS AND METHODS

This was a single-center, retrospective study. The study included 50 individuals who were diagnosed with NMOSD-ON (63 affected eyes) in a tertiary institution over a 12-year period. Data regarding any second, or higher, episodes of NMOSD-ON in each eye were not taken into consideration. Medical records of included individuals were reviewed. Demographic data, clinical and magnetic resonance imaging characteristics, and treatment outcomes were collected. Main outcome measures of the study were prognostic factors for good visual outcome (best-corrected visual acuity (BCVA) ≥ 20/200) following an initial episode of NMOSD-ON in affected eyes.

RESULTS

Sixty-three affected eyes of 50 individuals (3 men and 47 women) were included. BCVA at nadir that was better than counting fingers (CF) (odds ratio 10.43, 95% confidence interval 1.04, 104.45, p = 0.046) and time from NMOSD-ON onset to intravenous methylprednisolone (IVMP), less than 21 days (odds ratio 10.73, 95% confidence interval 1.91, 60.01, p = 0.007), were significantly associated with good visual outcomes.

CONCLUSION

BCVA at nadir that was better than CF and treatment with IVMP within 21 days of symptom onset were important prognostic factors of good visual outcomes following a first episode of NMOSD-ON in affected eyes.

Update on Pediatric Optic Neuritis

PURPOSE OF REVIEW

The purpose of this review is to provide an update on advances in the understanding of pediatric demyelinating optic neuritis.

RECENT FINDINGS

In the past decade, the disease phenotypes for demyelinating syndromes in children have been more clearly defined. Pediatric optic neuritis may present as a clinically isolated syndrome or in the setting of underlying neurologic disease. In addition to optic neuritis associated with multiple sclerosis or neuromyelitis optica, recent work has identified antibodies to the myelin oligodendrocyte glycoprotein (MOG IgG) as a unique demyelinating cause with distinct features regarding treatment and prognosis. The disease phenotypes for demyelinating pediatric optic neuritis have expanded. Treatment strategies vary and are not universally effective for each cause of demyelinating disease. Accurately distinguishing among these unique clinical syndromes is therefore critical for initiation of appropriate treatment to prevent disability, to maximize visual outcomes, and to provide insight into long-term prognosis.

Optic Neuritis

PURPOSE OF REVIEW

This article discusses the clinical presentation, evaluation, and management of the patient with optic neuritis. Initial emphasis is placed on clinical history, examination, diagnostic testing, and medical decision making, while subsequent focus is placed on examining specific inflammatory optic neuropathies. Clinical clues, examination findings, neuroimaging, and laboratory testing that differentiate autoimmune, granulomatous, demyelinating, infectious, and paraneoplastic causes of optic neuritis are assessed, and current treatments are evaluated.

RECENT FINDINGS

Advances in technology and immunology have enhanced our understanding of the pathologies driving inflammatory optic nerve injury. Clinicians are now able to interrogate optic nerve structure and function during inflammatory injury, rapidly identify disease-relevant autoimmune targets, and deliver timely therapeutics to improve visual outcomes.

SUMMARY

Optic neuritis is a common clinical manifestation of central nervous system inflammation. Depending on the etiology, visual prognosis and the risk for recurrent injury may vary. Rapid and accurate diagnosis of optic neuritis may be critical for limiting vision loss, future neurologic disability, and organ damage. This article will aid neurologists in formulating a systematic approach to patients with optic neuritis.

Brain Atrophy in Relapsing Optic Neuritis Is Associated With Crion Phenotype

Background and objective: Chronic relapsing inflammatory optic neuritis (CRION) is one of the more common phenotypes related to myelin oligodendrocyte glycoprotein antibodies (MOG-Abs). The absence of specific biomarkers makes distinguishing between CRION and relapsing inflammatory ON (RION) difficult. A recent work has suggested a widespread affectation of the central nervous system in CRION patients. In order to search for a potential CRION marker we have measured brain atrophy in a cohort of patients, stratified by phenotypes: CRION, RION, multiple sclerosis with a history of optic neuritis (MS-ON), and MOG-Abs status. Methods: A cross-sectional study was conducted in 31 patients (seven CRION, 11 RION, and 13 MS-ON). All patients were tested for MOG and aquaporin-4 antibodies (AQ4-Abs). Clinical data were collected. Brain atrophy was calculated by measuring the brain parenchyma fraction (BPF) with Neuroquant® software. Results: Four of seven CRION patients and one of 11 RION patients were positive for MOG-Abs (p = 0.046) and no MS-ON patients tested positive to MOG-Abs. All patients were negative to AQ4-Abs. The BPF was lower in patients with CRION than patients with RION (70.6 vs. 75.3%, p = 0.019) and similar to that in MS-ON patients. Conclusions: Brain atrophy in idiopathic inflammatory relapsing ON is present in patients with the CRION phenotype. Data from this study reflect that the optic nerve is a main target involved in these patients but not the only one. Our results should be further investigated in comprehensive and prospective studies.

Prevalence of Myelin Oligodendrocyte Glycoprotein and Aquaporin-4-IgG in Patients in the Optic Neuritis Treatment Trial

Importance

Autoantibodies to aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) are recently established biomarkers of autoimmune optic neuritis whose frequency and accompanying phenotype, especially for MOG-IgG, are still being characterized. The Optic Neuritis Treatment Trial (ONTT) was a well-known randomized clinical trial in optic neuritis; therefore, knowledge of the serostatus and accompanying phenotype of these patients would be useful to determine the frequency of these antibodies in patients presenting with typical monocular optic neuritis and their outcomes.

Objectives

To determine the AQP4-IgG and MOG-IgG serostatus of patients within the ONTT and describe the clinical features of seropositive patients.

Design, Setting, and Participants

In this follow-up study of the randomized clinical trial, ONTT, conducted between July 1, 1988, and June 30, 1991, analysis of serum for AQP4-IgG and MOG-IgG was performed from January 1 to April 30, 2017. A total of 177 patients from the ONTT with acute optic neuritis and serum available for analysis were enrolled from 13 academic referral centers.

Interventions

Analysis of serum for AQP4-IgG and MOG-IgG was performed at Mayo Clinic Neuroimmunology Laboratory in 2017 with a flow cytometry, live cell, AQP4- and MOG-transfected cell-based assay.

Main Outcomes and Measures

Aquaporin-4-IgG and MOG-IgG serostatus.

Results

Of the 177 patients in the study (135 women and 42 men; mean [SD] age, 32.8 [6.9] years), 3 were positive for MOG-IgG (1.7%) and none were positive for AQP4-IgG. All 3 patients positive for MOG-IgG had disc edema at presentation. Two patients later had a single episode of recurrent optic neuritis. All 3 patients had complete recovery of visual acuity, and none were corticosteroid dependent, although peripheral visual field loss persisted in 1 patient. None of the 3 patients positive for MOG-IgG had demyelinating lesions on magnetic resonance imaging scans, and none had developed multiple sclerosis at the 15-year follow-up.

Conclusions and Relevance

Frequency of MOG-IgG was rare in the ONTT, and AQP4-IgG was not found in patients in the ONTT. Characteristics of patients positive for MOG-IgG in the ONTT support the previously described phenotype of MOG-IgG optic neuritis. Myelin oligodendrocyte glycoprotein-related disease appears to be a different entity than multiple sclerosis. Overall, AQP4-IgG and MOG-IgG may be less common in isolated optic neuritis than previously reported.

Aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies in immune-mediated optic neuritis at long-term follow-up

OBJECTIVES

To re-evaluate serum samples from our 2007 cohort of patients with single-episode isolated ON (SION), recurrent isolated ON (RION), chronic relapsing inflammatory optic neuropathy (CRION), multiple sclerosis-associated ON (MSON) and neuromyelitis optica (NMO).

METHODS

We re-screened 103/114 patients with available serum on live cell-based assays (CBA) for aquaporin-4 (AQP4)-M23-IgG and myelin-oligodendrocyte glycoprotein (MOG)-α1-IgG. Further testing included oligoclonal bands, serum levels of glial fibrillar acidic and neurofilament proteins and S100B. We show the impact of updated serology on these patients.

RESULTS

Reanalysis of our original cohort revealed that AQP4-IgG seropositivity increased from 56% to 75% for NMO, 5% to 22% for CRION, 6% to 7% for RION, 0% to 7% for MSON and 5% to 6% for SION. MOG-IgG1 was identified in 25% of RION, 25% of CRION, 10% of SION, 0% of MSON and 0% of NMO. As a result, patients have been reclassified incorporating their autoantibody status. Presenting visual acuity was significantly worse in patients who were AQP4-IgG seropositive (p=0.034), but there was no relationship between antibody seropositivity and either ON relapse rate or visual acuity outcome.

CONCLUSIONS

The number of patients with seronegative CRION and RION has decreased due to improved detection of autoantibodies over the past decade. It remains essential that the clinical phenotype guides both antibody testing and clinical management. Careful monitoring of the disease course is key when considering whether to treat with prophylactic immune suppression.

A new M23-based ELISA assay for anti-aquaporin 4 autoantibodies: diagnostic accuracy and clinical correlation

Purpose

Although many assays have been developed to detect anti-aquaporin-4 (AQP4) antibodies, most of these assays require sophisticated techniques and are thus only available at specialized laboratories. The aim of this study was to evaluate the analytical and clinical performance of a new commercial enzyme-linked immunosorbent assay (ELISA RSR, AQP4 Ab Version 2) to detect anti-AQP4 antibodies performed on a fully automated system (SkyLAB 752).

Methods

Serum samples from 64 patients with neuromyelitis optica spectrum disorders (NMOSD) (including NMO, longitudinally extensive myelitis-LETM, optical neuritis and myelitis) and 27 controls were tested for anti-AQP4 antibodies. All sera were previously tested using an indirect immunofluorescence (IIF) method on primate tissue, as the reference method. Commercial control sera were used to determine within-run, between-day and within-laboratory precision (CLSI guidelines).

Results

At a cut-off value of 2.1 U/mL as determined by ROC curves, sensitivity and specificity for NMO were 83.3% and 100%, respectively. The ELISA assay provided 100% concordant results with the reference IIF method. The median concentration of anti-AQP4 antibodies was statistically higher in patients with NMO than in patients with LETM (p = 0.0006) or with other NMOSD and in controls (p < 0.0001). At the concentration of 12.4 and 28.1 U/mL, the within-run, between-day and within-laboratory coefficients of variation (CV) were 3.2% and 3%, 7.6% and 7.4%, and 8.2% and 8.0%, respectively.

Conclusions

This new ELISA method performed on a fully automated system, showed high sensitivity and absolute specificity, good CV in precision tests, and provided observer-independent quantitative results.

Pediatric optic neuritis

Optic neuritis in the pediatric population greatly differs from its presentation in the adult population. Firstly, it is usually bilateral in children and mostly unilateral in adults. (1,2,3) Second, it is generally associated with inflammation of the optic disc in pediatrics (1,2,3), whereas the inflammation is often retrobulbar in adults. (2) Finally, pediatric optic neuritis is often considered a post-infectious condition that is not usually associated with the subsequent development of multiple sclerosis (MS) (4,5,2), while in adults, the demyelinating event often precedes the clinical onset of MS. (6)

Antibodies to myelin oligodendrocyte glycoprotein in chronic relapsing inflammatory optic neuropathy

BACKGROUND/AIMS

To evaluate the status of myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) in chronic relapsing inflammatory optic neuropathy (CRION) and investigate its different clinical characteristics and prognosis.

METHODS

Patients diagnosed with CRION were recruited by the Neuro-ophthalmology Department of the Chinese People's Liberation Army General Hospital from December 2015 to April 2017. Based on antibody status, they were assigned to either the MOG-CRION or seronegative-CRION groups.

RESULTS

A total of 33 patients (38 eyes) were assessed and divided into the following groups: 22 (66.7%) MOG-CRION and 11 (33.3%) seronegative-CRION. The ratio of female to male was 1:1, and 81.8% of total CRION patients were adults (≥18 years). A total of 29 eyes (76.3%) showed severe visual loss (<20/200) during the first optic neuritis episode, and 37 eyes (72.5%) demonstrated good visual recovery (>20/40) during the final follow-up. The mean onset age of MOG-CRION patients was 28 ± 16 years (range 6-62), which was significantly younger than that of seronegative-CRION (45 ± 12 years, range 22-59) (p=0.029). The intraorbital and canalicular segments were highly involved in the orbital MRI of CRION patients. During the final follow-up, MOG-CRION patients had more bilateral involvement (p=0.008) and higher annualised relapse rates compared with the seronegative-CRION patients (p=0.019).

CONCLUSION

CRION was predominantly found in adults with unilateral ON and exhibited a higher rate of seropositive MOG-IgG. MOG-CRION, which may be a disparate subtype of MOG-IgG-induced demyelinating disease that needs further investigation, was found in younger patients at onset, with more bilateral involvement and more relapse tendency.

Chronic relapsing inflammatory optic neuropathy (CRION): a manifestation of myelin oligodendrocyte glycoprotein antibodies

Background

Key clinical features of chronic relapsing inflammatory optic neuropathy (CRION) include relapsing inflammatory optic neuritis (ON) and steroid dependency, both of which have been reported among patients with myelin oligodendrocyte glycoprotein antibodies (MOG-Abs). We investigated the relevance of the presence of serum MOG-IgG with the current diagnostic criteria for CRION among patients with idiopathic inflammatory optic neuritis (iON).

Methods

Retrospective reviews of a database prospectively collated between 2011 and 2017 from the tertiary referral center for multiple sclerosis and neuromyelitis optica were performed. Sixty-four patients with iON, who did not meet the diagnostic criteria for multiple sclerosis, neuromyelitis optica (NMO) spectrum disorder with/without NMO-IgG, or acute disseminated encephalomyelitis and who had no symptomatic central nervous system (CNS) lesions other than on the optic nerve, were included from a cohort of 615 patients with inflammatory demyelinating diseases of the CNS. Fulfillment of the current diagnostic criteria for CRION, assay results for the serum IgG1 MOG-Ab, and characteristics of CRION patients with MOG-IgG were compared to those of non-CRION patients with MOG-IgG.

Results

Twelve iON patients fulfilled the current diagnostic criteria for CRION, 11 patients were positive for MOG-IgG, and one patient was borderline. Among the other 52 iON patients not meeting the criteria for CRION, 14 had relapsing disease courses and 38 had monophasic courses, of which MOG-IgG positivity were 0% and 29%, respectively. CRION patients with MOG-IgG had more relapsing disease courses (first steroid-dependent worsening/relapse in 2.3 months, range 0.4–7.0) and poorer optical coherence tomography outcomes at follow-up than non-CRION patients with MOG-IgG. However, patients in the two groups did not differ in terms of age of onset, sex, or steroid treatment duration after initial attack.

Conclusions

CRION, according to the current diagnostic criteria, is a relapsing optic neuritis associated with MOG-IgG. Among iON patients with MOG-IgG, the absence of steroid-dependent attacks in the early stages of the disease may predict a long-term non-relapsing disease course and a more favorable outcome.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1335-x) contains supplementary material, which is available to authorized users.

Clinical Characteristics, Treatment Outcomes and Predictive Factors in Optic Neuritis

Background:

The causes, clinical presentations and treatment outcomes of optic neuritis are distinct among different populations. Early diagnosis based on clinical presentations plays an important role in treating optic neuritis patients.

Objective:

The study aimed to determine clinical characteristics, treatment outcomes and predictive factors of treatment outcomes in optic neuritis patients with and without demyelinating disease.

Methods:

A retrospective descriptive study of optic neuritis patients carried out between January 2009 and December 2016 was done. Univariate analysis and multivariate logistic regression analysis were used to evaluate the predictive factors of treatment outcomes.

Results:

Among 150 patients with optic neuritis, 58 patients were diagnosed with Neuromyelitis Optica Spectrum Disease (NMOSD), 23 patients were diagnosed with Multiple Sclerosis (MS) and 69 patients were idiopathic. The age at presentation in the NMOSD group was significantly younger than the MS group and the idiopathic group. The female:male ratio was significantly lower in the idiopathic group than in the NMOSD group. The initial Best Corrected Visual Activity (BCVA) of 20/20-20/60 (p = 0.001) and the idiopathic group (p =0.030) was associated with good visual outcomes. Initial BCVA of < 20/200 (p = 0.009) and the NMOSD group (p < 0.001) was associated with poor visual outcomes.

Conclusion:

NMOSD is a more common cause of optic neuritis than MS in Thai population. Female patients with poor initial VA, poor response to steroids treatment, and presenting recurrent attacks are highly suspicious for NMOSD. Optic neuritis without associated demyelinating disease has a better visual outcome and lower recurrence rate.

Neuromyelitis Optica: Review and Utility of Testing Aquaporin-4 Antibody in Typical Optic Neuritis

Neuromyelitis optica (NMO) is an autoimmune, inflammatory demyelinating disorder often leading to severe vision impairment and disability. The discovery of a diagnostic biomarker, the aquaporin-4 antibody (AQP4-IgG), transformed the clinical diagnosis and treatment of NMO and broadened the spectrum of disease [NMO spectrum disorders (NMOSD)]. Though the antibody is highly sensitive and specific to NMOSD, routine testing in patients with typical optic neuritis is considered controversial. This article will provide a brief review of NMOSD and highlight the pros and cons of routine testing in typical optic neuritis.

Recurrent Optic Neuritis as the Initial Symptom in Demyelinating Diseases

Background and Purpose

Optic neuritis (ON) is an inflammation of the optic nerve that can be recurrent, with unilateral or bilateral presentation. Diagnosing recurrent cases may be challenging. We aimed to compare patients with recurrent ON as their initial symptom according to their following final diagnoses: multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), or chronic relapsing inflammatory optic neuropathy (CRION).

Methods

The medical records of patients with initial recurrent ON who were followed at the Neuroimmunology Clinic of the Federal University of São Paulo between 2004 and 2016 were analyzed retrospectively. Patients were classified according to their final diagnosis into MS, NMOSD, or CRION, and the characteristics of these groups were compared to identify predictive factors.

Results

Thirty-three patients with recurrent ON were included, and 6, 14, and 13 had final diagnoses of MS, NMOSD, and CRION, respectively. Most of the patients were female with unilateral and severe ON in their first episode, and the initial Visual Functional System Score (VFSS) was ≥5 in 63.6%, 85.7%, and 16.7% of the patients with CRION, NMOSD, and MS, respectively. Anti-aquaporin-4 antibodies were detected in 9 of 21 (42.8%) tested patients. Seven of nine (77.8%) seropositive NMOSD patients experienced transverse myelitis episodes during the follow-up period. A multivariate regression analysis showed that the VFSS at the last medical appointment predicted the final diagnosis.

Conclusions

A lower VFSS at the last medical appointment was predictive of MS. Patients with NMOSD and CRION have similar clinical characteristics, whereas NMOSD patients tend to have worse visual acuity.

Clinical Profile and Outcomes of Optic Neuritis in an HIV Prevalent Urban Community in South Africa

PURPOSE:

To determine the clinical profile, causes and response to corticosteroid therapy in patients admitted and treated for optic neuritis at a tertiary hospital in Cape Town, South Africa.

METHODS:

A retrospective case review of 117 patients with optic neuritis between January 2002 and December 2012. Demographic information, clinical presentation, course of illness, investigations performed and visual outcomes at discharge and at three month follow up were collected for analysis.

RESULTS:

60 of 117 patients (51%) had an identifiable secondary cause for optic neuritis. Of the 57 patients with idiopathic optic neuritis, 14 had features associated with demyelinating disease. HIV and syphilis accounted for 62% of secondary causes of optic neuritis. Presenting visual acuity of hand movements (HM) or worse and absence of pain with extra ocular movement were associated with poorer final visual outcomes in the idiopathic optic neuritis group.

CONCLUSION:

Optic neuritis in our patients, as elsewhere in Africa, tends to be atypical in presentation. A high proportion of patients have an identifiable secondary cause. These patients thus require more extensive investigation in order to identify causes which may influence management. Secondary optic neuritis and idiopathic atypical optic neuritis carry a poorer prognosis than typical demyelinating optic neuritis.

Prognostic factors and disease course in aquaporin-4 antibody-positive Chinese patients with acute optic neuritis

The objective is to assess the frequency of AQP4-Ab in Chinese patients with optic neuritis (ON) and to investigate the prognostic implications of AQP4-Ab seropositivity in such patients. The presence of aquaporin-4 (AQP4) antibodies in human AQP4-transfected cells was determined by indirect immunofluorescence, and the diagnostic and prognostic relevance of AQP4 antibodies in 215 Chinese patients with optic neuritis was evaluated. The patients were enrolled from the Chinese People's Liberation Army General Hospital (PLAGH) and followed up to 1-228 months. Kaplan-Meier survival analysis was used to investigate the visual outcomes and prognostic characteristics of 70 patients who were aquaporin-4 antibody seropositive, and altogether 115 eyes were involved. AQP4-Ab was detectable in 70/215 (32.6%) patients with acute monosymptomatic optic neuritis. These AQP4-Ab seropositive patients were diagnosed as sufferers of neuromyelitis optica (NMO) (n = 10), NMO spectrum disease (NMOSD) (n = 41), multiple sclerosis (MS) (n = 1), and acute optic neuritis (AON) (n = 18). Moreover, AQP4-Ab levels did not vary between seropositive AON and NMO-ON and did not correlate with disease severity. Finally, the male gender, older age at onset, number of relapses, concomitant autoimmune antibodies, and optic lesions in magnetic resonance imaging (MRI) were associated with the AQP4-Ab seropositive status and the risk of developing permanent visual disability. Acute optic neuritis has a higher incidence of anti-aquaporin-4 antibody in China than in Western countries, and AQP4 antibody is a sensitive and specific biomarker for discriminating NMO-ON from other types of optic neuritis during the early stage of the disease course.

Distinct clinical characteristics of atypical optic neuritis with seronegative aquaporin-4 antibody among Chinese patients

OBJECTIVE

To evaluate the clinical features and prognosis of atypical optic neuritis (ON) with seronegative aquaporin-4 (AQP4) antibody in Chinese patients.

METHODS

All patients with first or relapsing ON were recruited from the Neuro-ophthalmology Department of the Chinese People's Liberation Army General Hospital from January 2013 to December 2014 and assigned to one of three groups based on diagnosis: atypical ON, typical ON and neuromyelitis optica spectrum disorder (NMOSD)-ON.

RESULTS

A total of 173 patients were included in the cohort. Fifty patients (28.9%) were AQP4-Ab-positive and diagnosed with NMOSD-ON. Of 123 patients with seronegative AQP4-Ab, 37 (30.1%) patients had atypical ON, with male predominance (25, 67.6%). The atypical ON group (compared with the typical ON and NMOSD-ON groups) had a significantly lower female:male ratio (1:2.1 vs 1.8:1 and 9:1, respectively, p=0.001 and p<0.001), an older mean age of onset (44.8, 13-71 years vs 36.9, 13-73 years and 36.2, 13-66 years, p=0.003 and p=0.004), a lower rate of good (≥0.5) visual recovery (6.7% vs 79.8% and 30.9%, p<0.001 and p<0.001) and (compared with the NMOSD-ON group) a lower recurrence rate during a 2-year follow-up (29.3% vs 60%, p=0.009). However, none developed to multiple sclerosis or neuromyelitis optica in the atypical ON group.

CONCLUSIONS

Atypical ON with seronegative AQP4-Ab had unique clinical features in this Chinese cohort, including male predominance, an older age of onset, worse visual acuity recovery and resistance to corticosteroid therapy. This condition may be a distinct nosological entity with an unusual clinical and therapeutic profile.

Combined brain and anterior visual pathways' MRIs assist in early identification of neuromyelitis optica spectrum disorder at onset of optic neuritis

Acute optic neuritis (ON) is the initial presentation in half of neuromyelitis optica spectrum disorder (NMO-SD) cases. Our objective was to evaluate accuracy of combined MRIs of the anterior visual pathways and of the brain to correctly identify NMO-SD among patients with acute ON. We performed a retrospective study on patients with acute ON in NMO-SD (16 episodes) and first-event non-NMO-SD (32 episodes). All MRIs included exams of the brain and anterior visual pathways using T2-weighted and post-gadolinium T1-weighted coronal thin slices. Images were reviewed by a neuroradiologist who was blinded to the final diagnosis. There were no multiple sclerosis (MS)-like lesions with dissemination in space (DIS) with NMO-SD (0 vs. 53%, p < 0.01). Non-NMO-SD ON usually spared the chiasma (3 vs. 44%, p < 0.01) and the optic tracts (0 vs. 19%, p < 0.01). Optic nerve lesions were longer [median (range) 26 mm (14-64) vs. 13 mm [8-36], p < 0.01] and the number of segments involved higher (3 [1-8] vs. 1 [1-4], p < 0.01) in NMO-SD. Bilateral optic nerve involvement, or involvement of ≥3 segments, or involvement of the chiasma, or optic tracts in the absence of MS-like lesions with DIS were suggestive of NMO-SD with a sensitivity of 69% (CI 95% 41-89) and a specificity of 97% (CI 95% 84-99) (p < 0.01). Combining brain and anterior visual pathways' MRIs seems efficient for detecting acute ON patients who are at high risk for NMO-SD.

Optic neuritis: a 5-year follow-up study of Chinese patients based on aquaporin-4 antibody status and ages

Little work has been performed on the long-term outcome of optic neuritis (ON) according to the status of aquaporin-4 antibody (AQP4-Ab) and long-term prognosis in older patients in China. This study retrospectively analyzed medical records in a cohort of Chinese patients with 5-year follow-up according to AQP4-Ab status and ages from January 2009 to December 2010. The clinical features, laboratory findings and risk factors for prognosis were analyzed. A total of 128 ON patients were included, 66.4 % of whom were female. The median age at onset was 36.8 years (range 18-73). Serum AQP4-Ab was positive in 45 (35.2 %) patients, with greater frequency in the female, bilateral, and recurrent ON groups (48.2, 42.5 and 53.6 %, respectively). Seropositive AQP4-Ab ON patients had worse visual recovery compared to seronegative patients (p = 0.033). The average and four quadrants of retinal nerve fiber layer (RNFL) thickness were significantly thinner in the seropositive group than in the seronegative group (p < 0.05). At 5-year follow-up, the ON recurrence rate was higher in the seropositive AQP4-Ab patients (37/45, 82.3 %) than in the seronegative patients (35/83, 42.2 %, p < 0.001). Among the seropositive patients, 40 % (18/45) developed neuromyelitis optica (NMO). Only 1.2 % (1/83) of the seronegative patients developed NMO and 4.8 % (4/83) developed to MS. Further, the multivariate analysis in seropositive AQP4-Ab patients showed that two risk factors for transverse myelitis (TM) episode were ocular pain and recurrence within 1 year. The older patients had worse visual outcome after the first episode of ON than the younger patients (p = 0.007). However, the two groups did not differ significantly with regard to prevalence of AQP4-Ab, long-term visual recovery and the risk of developing to NMO/MS.

Classification, diagnosis, and differential diagnosis of multiple sclerosis

PURPOSE OF REVIEW

The increasing availability of effective therapies for multiple sclerosis as well as research demonstrating the benefits of early treatment highlights the importance of expedient and accurate multiple sclerosis diagnosis. This review will discuss the classification, diagnosis, and differential diagnosis of multiple sclerosis.

RECENT FINDINGS

An international panel of multiple sclerosis experts, the MS Phenotype Group, recently revised the multiple sclerosis phenotypic classifications and published their recommendations in 2014. Recent research developments have helped improve the accuracy of multiple sclerosis diagnosis, especially with regard to differentiating multiple sclerosis from neuromyelitis optica spectrum disorders.

SUMMARY

Current multiple sclerosis phenotypic classifications include relapsing-remitting multiple sclerosis, clinically isolated syndrome, radiologically isolated syndrome, primary-progressive multiple sclerosis, and secondary-progressive multiple sclerosis. The McDonald 2010 diagnostic criteria provide formal guidelines for the diagnosis of relapsing-remitting multiple sclerosis and primary-progressive multiple sclerosis. These require demonstration of dissemination in space and time, with consideration given to both clinical findings and imaging data. The criteria also require that there exist no better explanation for the patient's presentation. The clinical history, examination, and MRI should be most consistent with multiple sclerosis, including the presence of features typical for the disease as well as the absence of features that suggest an alternative cause, for a diagnosis of multiple sclerosis to be proposed.

Autoimmune AQP4 channelopathies and neuromyelitis optica spectrum disorders

Neuromyelitis optica (NMO) spectrum disorders (SD) represent an evolving group of central nervous system (CNS)-inflammatory autoimmune demyelinating diseases unified by a pathogenic autoantibody specific for the aquaporin-4 (AQP4) water channel. It was historically misdiagnosed as multiple sclerosis (MS), which lacks a distinguishing biomarker. The discovery of AQP4-IgG moved the focus of CNS demyelinating disease research from emphasis on the oligodendrocyte and myelin to the astrocyte. NMO is recognized today as a relapsing disease, extending beyond the optic nerves and spinal cord to include brain (especially in children) and skeletal muscle. Brain magnetic resonance imaging abnormalities, identifiable in 60% of patients at the second attack, are consistent with MS in 10% of cases. NMOSD-typical lesions (another 10%) occur in AQP4-enriched regions: circumventricular organs (causing intractable nausea and vomiting) and the diencephalon (causing sleep disorders, endocrinopathies, and syndrome of inappropriate antidiuresis). Advances in understanding the immunobiology of AQP4 autoimmunity have necessitated continuing revision of NMOSD clinical diagnostic criteria. Assays that selectively detect pathogenic AQP4-IgG targeting extracellular epitopes of AQP4 are promising prognostically. When referring to AQP4 autoimmunity, we suggest substituting the term "autoimmune aquaporin-4 channelopathy" for the term "NMO spectrum disorders." Randomized clinical trials are currently assessing the efficacy and safety of newer immunotherapies. Increasing therapeutic options based on understanding the molecular pathogenesis is anticipated to improve the outcome for patients with AQP4 channelopathy.

Detection of Antibodies against Human and Plant Aquaporins in Patients with Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease that affects the body's central nervous system. Around 90% of MS sufferers are diagnosed with relapsing-remitting MS (RRMS). We used ELISA to measure IgG, IgA, and IgM antibodies against linear epitopes of human and plant aquaporins (AQP4) as well as neural antigens in RRMS patients and controls to determine whether patients suffering from RRMS have simultaneous elevations in antibodies against these peptides and antigens. In comparison to controls, significant elevations in isotype-specific antibodies against human and plant AQP4 and neural antigens such as MBP, MOG, and S100B were detected in RRMS patients, indicating a high correlation in antibody reaction between plant aquaporins and brain antigens. This correlation between the reactivities of RRMS patients with various tested antigens was the most significant for the IgM isotype. We conclude that a subclass of patients with RRMS reacts to both plant and human AQP4 peptides. This immune reaction against different plant aquaporins may help in the development of dietary modifications for patients with MS and other neuroimmune disorders.

Re-evaluating the treatment of acute optic neuritis

Clinical case reports and prospective trials have demonstrated a reproducible benefit of hypothalamic-pituitary-adrenal (HPA) axis modulation on the rate of recovery from acute inflammatory central nervous system (CNS) demyelination. As a result, corticosteroid preparations and adrenocorticotrophic hormones are the current mainstays of therapy for the treatment of acute optic neuritis (AON) and acute demyelination in multiple sclerosis.Despite facilitating the pace of recovery, HPA axis modulation and corticosteroids have failed to demonstrate long-term benefit on functional recovery. After AON, patients frequently report visual problems, motion perception difficulties and abnormal depth perception despite 'normal' (20/20) vision. In light of this disparity, the efficacy of these and other therapies for acute demyelination require re-evaluation using modern, high-precision paraclinical tools capable of monitoring tissue injury.In no arena is this more amenable than AON, where a new array of tools in retinal imaging and electrophysiology has advanced our ability to measure the anatomic and functional consequences of optic nerve injury. As a result, AON provides a unique clinical model for evaluating the treatment response of the derivative elements of acute inflammatory CNS injury: demyelination, axonal injury and neuronal degeneration.In this article, we examine current thinking on the mechanisms of immune injury in AON, discuss novel technologies for the assessment of optic nerve structure and function, and assess current and future treatment modalities. The primary aim is to develop a framework for rigorously evaluating interventions in AON and to assess their ability to preserve tissue architecture, re-establish normal physiology and restore optimal neurological function.

The Correlation between Aquaporin-4 Antibody and the Visual Function of Patients with Demyelinating Optic Neuritis at Onset

ON patients with AQP4-Ab seropositivity tend to be predominantly female and young and have worse visual acuity and more severe damage to their visual fields compared with AQP4-Ab seronegativity.

Aquaporin 4 antibody [NMO Ab] status in patients with severe optic neuritis in India

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system that causes attacks of optic neuritis and transverse myelitis. The discovery of a specific serum marker for NMO-IgG antibody [aquaporin 4 antibody/AQP4 Ab] has revolutionised the treatment of demyelinating diseases. Severe vision loss can be seen in optic neuritis (ON) associated with both multiple sclerosis (MS) and NMO. Identifying this antibody in optic neuritis patients can help us to establish the likelihood of these patients developing NMO (Jarius et al. Neurol Sci 298:158-162, 2010). It is important to differentiate these two entities as the treatment strategies of MS and NMO are different. To the best of our knowledge, there is no published literature regarding the importance of identifying this antibody in severe optic neuritis in Indian patients. Hence we decided to screen our severe optic neuritis patients for this AQP4 Ab. To investigate the presence of aquaporin 4 antibody and determine its prognostic value for visual and neurological outcome, in patients with bilateral and recurrent [severe] ON without any previous neurological manifestations presenting to a neuro-ophthalmology clinic in India. Single centre, prospective study. 40 patients (27 female patients and 13 male) with severe optic neuritis [patients with no visual improvement by 4 weeks from onset of vision loss] who presented either as recurrent attacks or as bilateral and severe optic neuritis between January 2010 and June 2011 were enrolled. Clinical features, visual outcome and sequential neurological events were compared between the seropositive and the seronegative groups. Aquaporin 4 antibodies were detected from serum using ELISA technique and IIF technique. Presence of this antibody in the serum was considered to be seropositive status and patients who did not have this antibody were considered seronegatives. AQP4 antibodies were detected in 8 of the 40 patients with severe ON (20 %).The female to male ratio in the seropositive group was 8:0. The NMO antibody titer ranged from 0.3 to 760 U/ml. ANA positivity in seropositive patients was statistically significant (p = 0.043). All seropositive patients had significantly poorer visual outcome as compared with the seronegative patients (p = 0.04).