Etiologies of acute demyelinating optic neuritis: an observational study of 110 patients

High diagnostic accuracy of T2FLAIR at 3 T in the detection of optic nerve head edema in acute optic neuritis

OBJECTIVES

Optic nerve head edema (ONHE) detected by fundoscopy is observed in one-third of patients presenting optic neuritis (ON). While ONHE is an important semiological feature, the correlation between ONHE and optic nerve head MRI abnormalities (ONHMA), sometimes called "optic nerve head swelling," remains unknown. Our study aimed to assess the diagnostic accuracy of T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence in detecting ONHE in patients with acute ON.

METHODS

In the present single-center study, data were extracted from two prospective cohort studies that consecutively included adults with a first episode of acute ON treated between 2015 and 2020. Two experienced readers blinded to study data independently analyzed imaging. A senior neuroradiologist resolved any discrepancies. The primary judgment criterion of ONHMA was assessed as optic nerve head high signal intensity on gadolinium-enhanced T2FLAIR MRI sequence. Its diagnostic accuracy was evaluated with both the gold standard of ONHE on fundus photography (FP) and peripapillary retinal nerve fiber layer thickening on optic coherence tomography (OCT).

RESULTS

A total of 102 patients were included, providing 110 affected and 94 unaffected optic nerves. Agreement was high between the different modalities: 92% between MRI and FP (k = 0.77, 95% CI: 0.67-0.88) and 93% between MRI and OCT (k = 0.77, 95% CI: 0.67-0.87). MRI sensitivity was 0.84 (95% CI: 0.70-0.93) and specificity was 0.94 (95% CI: 0.89-0.97) when compared with the FP.

CONCLUSION

Optic nerve head high T2FLAIR signal intensity corresponds indeed to the optic nerve head edema diagnosed by the ophthalmologists. MRI is a sensitive tool for detecting ONHE in patients presenting acute ON.

CLINICAL RELEVANCE STATEMENT

In patients with optic neuritis the high T2FLAIR (fluid-attenuated inversion recovery) signal intensity of the optic nerve head corresponds indeed to optic nerve head edema, which is a useful feature in optic neuritis etiological evaluation and treatment.

KEY POINTS

Optic nerve head edema is a prominent clinical feature of acute optic neuritis and is usually diagnosed during dilated or non-dilated eye fundus examination. Agreement was high between magnetic resonance imaging, fundus photography, and optical coherence tomography. Optic nerve head high T2 fluid attenuation inversion recovery signal intensity is a promising detection tool for optic nerve head edema in patients presenting acute optic neuritis.

Glial autoantibody prevalence in Chinese optic neuritis with onset after age 45: clinical factors for diagnosis

Purpose

As glial autoantibody testing is not yet available in some areas of the world, an alternative approach is to use clinical indicators to predict which subtypes of middle-aged and elderly-onset optic neuritis (ON) have manifested.

Method

This study was a single-center hospital-based retrospective cohort study. Middle-aged and elderly-onset ON patients (age > 45 years) who had experienced the first episode of ON were included in this cohort. Single- and multi-parametric diagnostic factors for middle-aged and elderly-onset myelin oligodendrocyte glycoprotein immunoglobulin-associated ON (MOG-ON) and aquaporin-4 immunoglobulin-related ON (AQP4-ON) were calculated.

Results

From January 2016 to January 2020, there were 81 patients with middle-aged and elderly-onset ON, including 32 (39.5%) AQP4-ON cases, 19 (23.5%) MOG-ON cases, and 30 (37.0%) Seronegative-ON cases. Bilateral involvement (47.4%, P = 0.025) was most common in the MOG-ON group. The presence of other concomitant autoimmune antibodies (65.6%, P = 0.014) and prior neurological history (37.5%, P = 0.001) were more common in the AQP4-ON group. The MOG-ON group had the best follow-up best-corrected visual acuity (BCVA) (89.5% ≤ 1.0 LogMAR, P = 0.001). The most sensitive diagnostic factors for middle-aged and elderly-onset MOG-ON were 'follow-up VA ≤ 0.1 logMAR' (sensitivity 0.89), 'bilateral involvement or follow-up VA ≤ 0.1 logMAR' (sensitivity 0.95), 'bilateral involvement or without neurological history' (sensitivity 1.00), and 'follow-up VA ≤ 0.1 logMAR or without neurological history' (sensitivity 1.00), and the most specific factor was 'bilateral involvement' (specificity 0.81). The most sensitive diagnostic factors for middle-aged and elderly-onset AQP4-ON were 'unilateral involvement' (sensitivity 0.88), 'unilateral involvement or neurological history' (sensitivity 0.91), and 'unilateral involvement or other autoimmune antibodies' (sensitivity 1.00), and the most specific factor was neurological history (specificity 0.98).

Conclusion

Based on our cohort study of middle-aged and elderly-onset ON, MOG-ON is less prevalent than AQP4-ON and Seronegative-ON. Using multiple combined parameters improves the sensitivity and negative predictive value for diagnosing middle-aged and elderly-onset MOG-ON and AQP4-ON. These combined parameters can help physicians identify and treat middle-aged and elderly-onset ON early when glial autoantibody status is not available.

The Potential Pathogenicity of Myelin Oligodendrocyte Glycoprotein Antibodies in the Optic Pathway

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an acquired inflammatory demyelinating disease with optic neuritis (ON) as the most frequent clinical symptom. The hallmark of the disease is the presence of autoantibodies against MOG (MOG-IgG) in the serum of patients. Whereas the role of MOG in the experimental autoimmune encephalomyelitis animal model is well-established, the pathogenesis of the human disease and the role of human MOG-IgG is still not fully clear.

EVIDENCE ACQUISITION

PubMed was searched for the terms "MOGAD," "optic neuritis," "MOG antibodies," and "experimental autoimmune encephalomyelitis" alone or in combination, to find articles of interest for this review. Only articles written in English language were included and reference lists were searched for further relevant papers.

RESULTS

B and T cells play a role in the pathogenesis of human MOGAD. The distribution of lesions and their development toward the optic pathway is influenced by the genetic background in animal models. Moreover, MOGAD-associated ON is frequently bilateral and often relapsing with generally favorable visual outcome. Activated T-cell subsets create an inflammatory environment and B cells are necessary to produce autoantibodies directed against the MOG protein. Here, pathologic mechanisms of MOG-IgG are discussed, and histopathologic findings are presented.

CONCLUSIONS

MOGAD patients often present with ON and harbor antibodies against MOG. Furthermore, pathogenesis is most likely a synergy between encephalitogenic T and antibody producing B cells. However, to which extent MOG-IgG are pathogenic and the exact pathologic mechanism is still not well understood.

Optic neuritis and autoimmune optic neuropathies: advances in diagnosis and treatment

Optic neuritis is an inflammatory optic neuropathy that is commonly indicative of autoimmune neurological disorders including multiple sclerosis, myelin-oligodendrocyte glycoprotein antibody-associated disease, and neuromyelitis optica spectrum disorder. Early clinical recognition of optic neuritis is important in determining the potential aetiology, which has bearing on prognosis and treatment. Regaining high-contrast visual acuity is common in people with idiopathic optic neuritis and multiple sclerosis-associated optic neuritis; however, residual deficits in contrast sensitivity, binocular vision, and motion perception might impair vision-specific quality-of-life metrics. In contrast, recovery of visual acuity can be poorer and optic nerve atrophy more severe in individuals who are seropositive for antibodies to myelin oligodendrocyte glycoprotein, AQP4, and CRMP5 than in individuals with typical optic neuritis from idiopathic or multiple-sclerosis associated optic neuritis. Key clinical, imaging, and laboratory findings differentiate these disorders, allowing clinicians to focus their diagnostic studies and optimise acute and preventive treatments. Guided by early and accurate diagnosis of optic neuritis subtypes, the timely use of high-dose corticosteroids and, in some instances, plasmapheresis could prevent loss of high-contrast vision, improve contrast sensitivity, and preserve colour vision and visual fields. Advancements in our knowledge, diagnosis, and treatment of optic neuritis will ultimately improve our understanding of autoimmune neurological disorders, improve clinical trial design, and spearhead therapeutic innovation.

MOG antibody prevalence in adult optic neuritis and clinical predictive factors for diagnosis: A Chinese cohort study

OBJECTIVE

Because AQP4/MOG antibody testing is not available in some parts of the world and there are often delays in obtaining results, it is particularly important to use clinical factors to predict the subtypes of adult optic neuritis (ON).

METHODS

This was a single-center retrospective cohort study.

RESULTS

The final analysis included 249 adult patients presenting with the first ON attack during January 2016 to January 2020. These included 109 (43.8%) AQP4-ON cases, 49 (19.7%) MOG-ON cases, and 91 (36.5%) Seronegative-ON cases. The proportion of optic disk swelling (ODS) and bilateral involvement in MOG-ON group was significantly higher than in the other two subgroups (P = 0.029, 0.001). The MOG-ON group had the best follow-up BCVA (P = 0.003). To predict adult AQP4-ON, unilateral involvement (sensitivity 0.88, NPV 0.77) was the most sensitivity predictors, while neurological history (specificity 0.96, PPV 0.65) and concomitant other autoimmune antibodies (specificity 0.76, PPV 0.65) were the most specific predictors. Using the parallel test 'unilateral or other autoimmune antibodies' increased sensitivity to 0.95, with an optimal NPV of 0.88. To predict adult MOG-ON, the most sensitive clinical characteristics were ODS (sensitivity 0.79, NPV 0.88), and follow-up VA ≤0.1logMAR (sensitivity 0.78, NPV 0.92), whereas the most specific values were prior neurological history or bilateral involvement, with specificities of 0.92 and 0.82, respectively. The sensitivity increased to 0.94, 0.97, and 0.97 when using the parallel clinical factors of 'bilateral or ODS or relapse', 'bilateral or ODS or follow-up VA ≤0.1logMAR', and 'ODS or follow-up VA ≤0.1logMAR', and the corresponding NPV (0.94, 0.97 vs 0.98).

CONCLUSION

The proportion of MOG-ON (19.7%) was less than that of AQP4-ON and Seronegative-ON. Moreover, MOG-ON had a better prognosis and was more likely to be associated with ODS or bilateral involvement. The use of parallel clinical parameters improved the sensitivity for the diagnosis of adult MOG-ON and AQP4-ON.

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.

MRI characteristics of MOG-Ab associated disease in adults: An update

Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.

AQP4-IgG and MOG-IgG Related Optic Neuritis-Prevalence, Optical Coherence Tomography Findings, and Visual Outcomes: A Systematic Review and Meta-Analysis

Background: Optic neuritis (ON) is a cardinal manifestation of multiple sclerosis (MS), aquaporin-4 (AQP4)-IgG-, and myelin oligodendrocyte glycoprotein (MOG)-IgG-associated disease. However, the prevalence of AQP4-IgG seropositivity and MOG-IgG seropositivity in isolated ON is unclear, and studies comparing visual outcomes and optical coherence tomography (OCT)-derived structural retinal measures between MS-ON, AQP4-ON, and MOG-ON eyes are limited by small sample sizes. Objectives: (1) To assess the prevalence of AQP4-IgG and MOG-IgG seropositivity among patients presenting with isolated ON; (2) to compare visual outcomes and OCT measures between AQP4-ON, MOG-ON, and MS-ON eyes. Methods: In this systematic review and meta-analysis, a total of 65 eligible studies were identified by PubMed search. Statistical analyses were performed with random effects models. Results: In adults with isolated ON, AQP4-IgG seroprevalence was 4% in non-Asian and 27% in Asian populations, whereas MOG-IgG seroprevalence was 8 and 20%, respectively. In children, AQP4-IgG seroprevalence was 0.4% in non-Asian and 15% in Asian populations, whereas MOG-IgG seroprevalence was 47 and 31%, respectively. AQP4-ON eyes had lower peri-papillary retinal nerve fiber layer (pRNFL; -11.7 μm, 95% CI: -15.2 to -8.3 μm) and macular ganglion cell + inner plexiform layer (GCIPL; -9.0 μm, 95% CI: -12.5 to -5.4 μm) thicknesses compared with MS-ON eyes. Similarly, pRNFL (-11.2 μm, 95% CI: -21.5 to -0.9 μm) and GCIPL (-6.1 μm, 95% CI: -10.8 to -1.3 μm) thicknesses were lower in MOG-ON compared to MS-ON eyes, but did not differ between AQP4-ON and MOG-ON eyes (pRNFL: -1.9 μm, 95% CI: -9.1 to 5.4 μm; GCIPL: -2.6 μm, 95% CI: -8.9 to 3.8 μm). Visual outcomes were worse in AQP4-ON compared to both MOG-ON (mean logMAR difference: 0.60, 95% CI: 0.39 to 0.81) and MS-ON eyes (mean logMAR difference: 0.68, 95% CI: 0.40 to 0.96) but were similar in MOG-ON and MS-ON eyes (mean logMAR difference: 0.04, 95% CI: -0.05 to 0.14). Conclusions: AQP4-IgG- and MOG-IgG-associated disease are important diagnostic considerations in adults presenting with isolated ON, especially in Asian populations. Furthermore, MOG-IgG seroprevalence is especially high in pediatric isolated ON, in both non-Asian and Asian populations. Despite a similar severity of GCIPL and pRNFL thinning in AQP4-ON and MOG-ON, AQP4-ON is associated with markedly worse visual outcomes.

Etiologies of Acute Optic Neuritis in Thailand: An Observational Study of 171 Patients

Purpose

To analyze the demographic patterns, clinical characteristics and etiologies of acute optic neuritis (ON).

Methods

This retrospective observational study included patients with acute ON who presented to a university hospital in Bangkok, Thailand, between January 2010 and March 2020. The demographic details, clinical characteristics and etiologies of acute ON were evaluated.

Results

A total of 171 patients were included in the study (78.4% [n=134] female; mean age 45 years [standard deviation 15.4 years]; 32.2% [n=55] bilateral involvement). The most common type of acute ON was idiopathic (51.5%), followed by neuromyelitis optica spectrum disorder (NMOSD, 30.9%), other autoimmune disorders (9.9%), myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD, 5.3%), multiple sclerosis (MS, 1.8%), and postinfection (0.6%). In the other autoimmune disorders group, 2 patients developed systemic lupus erythematosus (1.2%), 2 Sjogren’s syndrome (1.2%), 1 RA (0.6%), 1 anti-NMDAR (0.6%), 3 anti-Jo1 (1.8%), 2 c-ANCA (1.2%), 1 anti-centromere (0.6%), and 5 nonspecific autoimmune disorders (2.9%). In the idiopathic group, 38.6% developed single isolated ON, 1.8% relapsing isolated ON and 11.1% chronic relapsing inflammatory optic neuropathy.

Conclusion

The most common form of acute ON in this study, similar to other Asian countries, was idiopathic. Idiopathic-ON shared some phenotypes with NMOSD and MOGAD. We also reported patients with anti-NMDAR, anti-Jo1, c-ANCA and anti-centromere disorders. Improvements in antibody detection have widened the range of possible etiologies of acute ON. The study highlighted the important role of antibodies in creating effective treatments in the future.

Serum Level of the Angiotensin-Converting Enzyme in Patients with Idiopathic Acute Optic Neuritis: A Case-Control Study

PURPOSE

To evaluate the serum level of angiotensin-converting enzyme (ACE) as an important component of the renin-angiotensin system (RAS) in optic neuritis (ON) compared to the healthy control group in the context investigating the possible role of ACE in ON pathogenesis.

METHODS

This case-control study was conducted on patients with ON and healthy controls. Serum ACE levels were assessed and compared between the two groups by using commercially available kits by ELISA for ACE.

RESULTS

Sixty-five ON patients (75.4% female, mean age 29.70 ± 8.30 years) and 65 controls (75.4% female, mean age 29.66 ± 8.36 years) were enrolled. The median serum ACE levels were 33.5 U/L (range: 25-540) and 26 U/L (range: 22.3-72) for the ON patients and controls, respectively. Serum ACE levels were significantly higher in the patients than in the control group (P < 0.001). High level of serum ACE (defined as a serum ACE >65 U/L) was present in 9 (13.8%) patients with ON and 2 (3.1%) controls.

CONCLUSION

Our results indicated that the serum level of ACE appeared to be significantly higher in acute ON than in normal controls.

MOG-Ab prevalence in optic neuritis and clinical predictive factors for diagnosis

OBJECTIVE

What is the proportion of antibodies to myelin oligodendrocyte glycoprotein (MOG-Ab) in optic neuritis (ON) in adults and what would be the ON presentation for which MOG-Ab should be tested?

METHODS

Multicentric prospective study conducted during 1 year on all patients diagnosed with acute ON in all ophthalmological units in hospitals in a region in western France.

RESULTS

Sixty-five patients were included. MOG-Ab prevalence was 14% (9/65) during an acute ON and 13% (7/55) after exclusion of patients already diagnosed with multiple sclerosis (MS) (8) or MOG+ON (2). Compared with MS and clinically isolated syndrome, MOG+ON had no female preponderance (67% of men in case of MOG+ON and 22% of men in case of MS and clinically isolated syndrome, p<0.05) were more often bilateral (44% vs 3%, p<0.005) and associated with optic disc swelling (ODS) (78% vs 14%, p<0.001). To predict MOG+ON, the positive predictive values (PPVs) of male sex, ODS and bilateral involvement were 29% (95% CI 9% to 48%), 41% (95% CI 18% to 65%) and 40% (95% CI 10% to 70%), respectively, while the negative predictive values (NPV) were 93% (95% CI 86% to 100%), 96% (95% CI 90% to 100%) and 91% (95% CI 83% to 99%), respectively. The combined factor 'ODS or bilateral or recurrent ON' was the best compromise between PPV (31% (95% CI 14% to 48%)) and NPV (100% (95% CI 100% to 100%)).

CONCLUSION

Among ON episodes, MOG-Ab were found in 14% of cases. MOG+ON occurred without female preponderance and was significantly associated with ODS and/or bilateral ON. Testing MOG-Ab only in patients presenting with ODS or bilateral or recurrent ON would limit MOG-Ab tests to fewer than half of all patients without the risk of missing any MOG+ON cases.

A new association: acute macular neuroretinopathy in acute optic neuritis

Background

Acute optic neuritis (AON) is a common optic nerve disease leading to retrograde degeneration of optic nerve axons, reflected by thinning of the inner retinal layers on optical coherence tomography. On the contrary, acute macular neuroretinopathy (AMN) type 2 is a rare outer retinal disorder that leads to thinning of the outer nuclear layers and is diagnosed by multimodal imaging. The aim of this study was to report a new association between these two diseases.

Methods

Patients with a first episode of optic neuritis were invited to participate in a study that involved optical coherence tomography evaluation at baseline and the following 1, 3, 6 and 12 months. All the study patients underwent ophthalmologic evaluation that comprised of visual acuity, visual field and multimodal imaging as well as orbital and brain Magnetic Resonance Imaging. A diagnosis of multiple sclerosis was made according to the 2010 McDonald criteria.

Results

Six of the 114 patients with acute optic neuritis also had acute macular neuroretinopathy, of whom three were positive for myelin oligodendrocyte glycoprotein antibodies (MOG‐Abs), two had relapsing–remitting multiple sclerosis and one had clinical isolated syndrome.

Conclusion

Our study suggests that it is imperative to check for associated AMN in cases of AON, especially those associated with MOG‐Abs.

The prevalence and prognostic value of myelin oligodendrocyte glycoprotein antibody in adult optic neuritis

BACKGROUND AND OBJECTIVE

Adult demyelinating optic neuritis (ON) with positive myelin-oligodendrocyte glycoprotein antibody (MOG-Ab) has distinct clinical features. This study aimed to investigate the point prevalence, relationship with steroid dependency and prognosis value of MOG-Ab in adult ON.

METHODS

Clinical data analysis was undertaken in adults with ON admitted between December 2014 and January 2016. Patients were classified into three groups based on aquaporin-4 antibody (AQP4-Ab) and MOG-Ab status: AQP4-ON, MOG-ON and seronegative-ON.

RESULTS

A total of 158 adults with ON (190 eyes) were assessed, including 31 MOG-ON (19.6%), 67 AQP4-ON (42.4%) and 60 seronegative-ON (38.0%) cases. The female-to-male ratio was significantly lower in MOG-ON (1.8:1) than that in AQP4-ON (8.6:1) groups (p = .005). The median age, percentage of bilateral ON and visual loss at the nadir at onset was similar among the three groups. Thirty-eight eyes (76%) in the MOG-ON group showed good visual recovery (>20/40) in the final visit, which is statistically better than that in the AQP4-ON and seronegative-ON groups (p < .001 and p = .006, resoectively). Fifteen adults with ON (9.5%) showed dependency on steroid, which was particularly prominent in the MOG-ON group (11/31, 35.5%) and rarely presented in the AQP4-ON (2, 3.0%) and seronegative-ON (2, 3.3%) groups. Results suggested less loss of pRNFL in MOG-ON than that in AQP4-ON group (p < .001), and a larger proportion of canalicular segment involved in MOG-ON adults (p = .007 and p < .001).

CONCLUSION

MOG-ON had the smallest proportion of acute demyelinating ON in Chinese adults. One third of adults with MOG-ON predominantly showed a substantial dependency on steroids and relapse on steroid reduction or cessation, which rarely presented in AQP4-ON and seronegative-ON adults.

Aquaporin-4 and Myelin Oligodendrocyte Glycoprotein Autoantibody Status Predict Outcome of Recurrent Optic Neuritis

PURPOSE

To determine the aquaporin-4 and myelin oligodendrocyte glycoprotein (MOG) immunoglobulin G (IgG) serostatus and visual outcomes in patients with recurrent optic neuritis (rON) initially seeking treatment.

DESIGN

Cross-sectional cohort study.

PARTICIPANTS

The study identified patients by searching the Mayo Clinic computerized central diagnostic index (January 2000-March 2017). The 246 eligible patients fulfilled the following criteria: (1) initially seeking treatment for at least 2 consecutive episodes of optic neuritis (ON) and (2) serum available for testing.

METHODS

Serum was tested for aquaporin-4 IgG and MOG IgG1 using an in-house validated flow cytometric assay using live HEK293 cells transfected with M1 aquaporin-4 or full-length MOG.

MAIN OUTCOMES MEASURES

Aquaporin-4 IgG and MOG IgG1 serostatus, clinical characteristics, and visual outcomes.

RESULTS

Among 246 patients with rON at presentation, glial autoantibodies were detected in 32% (aquaporin-4 IgG, 19%; MOG IgG1, 13%); 186 patients had rON only and 60 patients had rON with subsequent additional inflammatory demyelinating attacks (rON-plus group). The rON-only cohort comprised the following: double seronegative (idiopathic), 110 patients (59%); MOG IgG1 positive, 27 patients (15%; 4 with chronic relapsing inflammatory optic neuropathy); multiple sclerosis (MS), 25 patients (13%); and aquaporin-4 IgG positive, 24 patients (13%). The rON-plus cohort comprised the following: aquaporin-4 IgG positive, 23 patients (38%); MS, 22 patients (37%); double seronegative, 11 patients (18%); and MOG IgG1 positive, 4 patients (7%). The annualized relapse rate for the rON-only group was 1.2 for MOG IgG1-positive patients, 0.7 for double-seronegative patients, 0.6 for aquaporin-4 IgG-positive patients, and 0.4 for MS patients (P = 0.005). The median visual acuity (VA) of patients with the worst rON-only attack at nadir were hand movements in aquaporin-4 IgG-positive patients, between counting fingers and hand movements in MOG IgG1-positive patients, 20/800 in idiopathic patients, and 20/100 in MS patients (P = 0.02). The median VA at last follow-up for affected eyes of the rON-only cohort were counting fingers for aquaporin-4 IgG-positive patients, 20/40 for idiopathic patients, 20/25 for MS patients and MOG IgG1-positive patients (P = 0.006). At 5 years after ON onset, 59% of aquaporin-4 IgG-positive patients, 22% of idiopathic patients, 12% of MOG IgG1-positive patients, and 8% of MS patients were estimated to have severe visual loss.

CONCLUSIONS

Glial autoantibodies (MOG IgG1 or aquaporin-4 IgG) are found in one third of all patients with rON. Aquaporin-4 IgG seropositivity predicts a worse visual outcome than MOG IgG1 seropositivity, double seronegativity, or MS diagnosis. Myelin oligodendrocyte glycoprotein IgG1 is associated with a greater relapse rate but better visual outcomes.

Clinical spectrum and IgG subclass analysis of anti-myelin oligodendrocyte glycoprotein antibody-associated syndromes: a multicenter study

Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) recently emerged as a potential biomarker in patients with inflammatory demyelinating diseases of the central nervous system. We here compare the clinical and laboratory findings observed in a cohort of MOG-Ab seropositive and seronegative cases and describe IgG subclass analysis results. Consecutive serum samples referred to Verona University Neuropathology Laboratory for aquaporin-4 (AQP4)-Ab and/or MOG-Ab testing were analysed between March 2014 and May 2017. The presence of AQP4-Ab was determined using a cell-based assay. A live cell immunofluorescence assay was used for the detection of MOG-IgG and IgG subclass analysis. Among 454 analysed samples, 29 were excluded due to AQP4-Ab positivity or to the final demonstration of a disorder not compatible with MOG-Ab. We obtained clinical data in 154 out of 425 cases. Of these, 22 subjects resulted MOG-Ab positive. MOG-Ab positive patients were mainly characterised by the involvement of the optic nerve and/or spinal cord. Half of the cases presented relapses and the recovery was usually partial. Brain MRI was heterogeneous while short lesions were the prevalent observation on spinal cord MRI. MOG-Ab titre usually decreased in non-relapsing cases. In all MOG-IgG positive cases, we observed IgG1 antibodies, which were predominant in most subjects. IgG2 (5/22), IgG3 (9/22) and IgG4 (3/22) antibodies were also detectable. We confirm that MOG-Ab-related syndromes have distinct features in the spectrum of demyelinating conditions, and we describe the possible role of the different IgG subclasses in this condition.