Detection of MOG-IgG by cell-based assay: moving from discovery to clinical practice

Artificial intelligence and omics-based autoantibody profiling in dementia

Introduction

Dementia is a neurodegenerative syndrome marked by the accumulation of disease-specific proteins and immune dysregulation, including autoimmune mechanisms involving autoantibodies. Current diagnostic methods are often invasive, time-consuming, or costly.

Methods

This study explores the use of proteome-wide autoantibody screening (PWAbS) for noninvasive dementia diagnosis by analyzing serum samples from Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and age-matched cognitively normal individuals (CNIs). Serum samples from 35 subjects were analyzed utilizing our original wet protein arrays displaying more than 13,000 human proteins.

Results

PWAbS revealed elevated gross autoantibody levels in AD and DLB patients compared to CNIs. A total of 229 autoantibodies were differentially elevated in AD and/or DLB, effectively distinguishing between patient groups. Machine learning models showed high accuracy in classifying AD, DLB, and CNIs. Gene ontology analysis highlighted autoantibodies targeting neuroactive ligands/receptors in AD and lipid metabolism proteins in DLB. Notably, autoantibodies targeting neuropeptide B (NPB) and adhesion G protein-coupled receptor F5 (ADGRF5) showed significant correlations with clinical traits including Mini Mental State Examination scores.

Discussion

The study demonstrates the potential of PWAbS and artificial intelligence integration as a noninvasive diagnostic tool for dementia, uncovering biomarkers that could enhance understanding of disease mechanisms. Limitations include demographic differences, small sample size, and lack of external validation. Future research should involve longitudinal observation in larger, diverse cohorts and functional studies to clarify autoantibodies' roles in dementia pathogenesis and their diagnostic and therapeutic potential.

Thalamic volume differentiates multiple sclerosis from neuromyelitis optica spectrum disorder: MRI-based retrospective study

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are distinct demyelinating diseases of the central nervous system, each characterized by unique patterns of motor, sensory, and visual dysfunction. While MS typically affects the brain and spinal cord, NMOSD predominantly targets the optic nerves and spinal cord. This study aims to elucidate the morphometric differences between MS and NMOSD by focusing on gray matter volume changes in specific brain regions. We also examined if temporal changes in follow-up MRI differentiate the two disorders. We analyzed anatomical T1-weighted MRI scans from 24 patients with NMOSD and 25 patients with MS using the CAT12 toolbox. Our analysis revealed significant differences in gray matter structure between the two patient groups. Notably, the thalamus was found to be consistently smaller in patients with MS compared to those with NMOSD. This finding aligns with previous research highlighting thalamic atrophy as a hallmark of MS and further underscores the thalamus's role in the disease's pathology. These results provide valuable insights into the distinct neuroanatomical features of MS and NMOSD, contributing to a better understanding of the mechanisms underlying these diseases. The study also emphasizes the importance of advanced imaging techniques in differentiating between MS and NMOSD, which may have implications for diagnosis and treatment strategies.

Turncoat antibodies unmasked in a model of autoimmune demyelination: from biology to therapy

Autoantibodies contribute to many autoimmune diseases, yet there is no approved therapy to neutralize them selectively. A popular mouse model, experimental autoimmune encephalomyelitis (EAE), could serve to develop such a therapy, provided we can better understand the nature and importance of the autoantibodies involved. Here we report the discovery of autoantibody-secreting extrafollicular plasmablasts in EAE induced with specific myelin oligodendrocyte glycoprotein (MOG) antigens. Single-cell RNA sequencing reveals that these cells produce non-affinity-matured IgG antibodies. These include pathogenic antibodies competing for shared binding space on MOG's extracellular domain. Interestingly, the synthetic anti-MOG antibody 8-18C5 can prevent the binding of pathogenic antibodies from either EAE mice or people with MOG antibody disease (MOGAD). Moreover, an 8-18C5 variant carrying the NNAS mutation, which inactivates its effector functions, can reduce EAE severity and promote functional recovery. In brief, this study provides not only a comprehensive characterization of the humoral response in EAE models, but also a proof of concept for a novel therapy to antagonize pathogenic anti-MOG antibodies.

MOG Antibody Disease: Nuances in Presentation, Diagnosis, and Management

PURPOSE OF REVIEW

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is a distinct neuroinflammatory condition characterized by attacks of optic neuritis, transverse myelitis, and other demyelinating events. Though it can mimic multiple sclerosis and neuromyelitis optica spectrum disorder, distinct clinical and radiologic features which can discriminate these conditions are now recognized. This review highlights recent advances in our understanding of clinical manifestations, diagnosis, and treatment of MOGAD.

RECENT FINDINGS

Studies have identified subtleties of common clinical attacks and identified more rare phenotypes, including cerebral cortical encephalitis, which have broadened our understanding of the clinicoradiologic spectrum of MOGAD and culminated in the recent publication of proposed diagnostic criteria with a familiar construction to those diagnosing other neuroinflammatory conditions. These criteria, in combination with advances in antibody testing, should simultaneously lead to wider recognition and reduced incidence of misdiagnosis. In addition, recent observational studies have raised new questions about when to treat MOGAD chronically, and with which agent. MOGAD pathophysiology informs some of the relatively unique clinical and radiologic features which have come to define this condition, and similarly has implications for diagnosis and management. Further prospective studies and the first clinical trials of therapeutic options will answer several remaining questions about the peculiarities of this condition.

Assessing the applicability of the 2023 international MOGAD panel criteria in real-world clinical settings

INTRODUCTION

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a recently identified demyelinating disorder with a diverse clinical spectrum. Diagnosing MOGAD traditionally relies on clinical judgment, highlighting the necessity for precise diagnostic criteria. Banwell et al. proposed criteria, aiming to refine the diagnostic spectrum. This study evaluates these criteria in a real-life cohort, comparing their performance with clinical judgment and describe the cohort of MOGAD patients.

METHODS

This retrospective study, conducted at Hadassah Medical Center, included 88 patients with MOG-IgG antibodies. Patients with a positive or borderline MOG-IgG antibodies by cell-based assay were included. Demographics, clinical and MRI data were recorded. Cases were divided into definite MOGAD and Non-MOGAD groups as determined by the treating physician. We assessed the sensitivity and specificity of the new criteria in comparison to treating physicians' evaluations. Additionally, we examined clinical differences between the MOGAD and Non-MOGAD groups.

RESULTS

We observed a strong concordance (98%) between the new MOGAD criteria and treating physicians' diagnoses. Clinical disparities between MOGAD and Non-MOGAD groups included lower EDSS scores, normal MRI scans, preserved brain volume, negative OCB results, and distinct relapse patterns. Also, compared to relapsing patients, monophasic MOGAD patients have greater brain volume and a lower age at onset.

CONCLUSION

The study demonstrates robust accuracy of new MOGAD criteria, emphasizing their potential to enhance diagnostic precision. Treatment response integration into the MOGAD diagnosis is crucial, as it could aid in distinguishing MOGAD from other demyelinating disorders. Distinct clinical profiles highlight the importance of informed decisions in managing MOGAD and similar disorders.

Differentiation between multiple sclerosis and neuromyelitis optica spectrum disorder using a deep learning model

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory disorders of the central nervous system (CNS) with similar characteristics. The differential diagnosis between MS and NMOSD is critical for initiating early effective therapy. In this study, we developed a deep learning model to differentiate between multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) using brain magnetic resonance imaging (MRI) data. The model was based on a modified ResNet18 convolution neural network trained with 5-channel images created by selecting five 2D slices of 3D FLAIR images. The accuracy of the model was 76.1%, with a sensitivity of 77.3% and a specificity of 74.8%. Positive and negative predictive values were 76.9% and 78.6%, respectively, with an area under the curve of 0.85. Application of Grad-CAM to the model revealed that white matter lesions were the major classifier. This compact model may aid in the differential diagnosis of MS and NMOSD in clinical practice.

Differentiating Multiple Sclerosis From AQP4-Neuromyelitis Optica Spectrum Disorder and MOG-Antibody Disease With Imaging

BACKGROUND AND OBJECTIVES

Relapsing-remitting multiple sclerosis (RRMS), aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may have overlapping clinical features. There is an unmet need for imaging markers that differentiate between them when serologic testing is unavailable or ambiguous. We assessed whether imaging characteristics typical of MS discriminate RRMS from AQP4-NMOSD and MOGAD, alone and in combination.

METHODS

Adult, nonacute patients with RRMS, APQ4-NMOSD, and MOGAD and healthy controls were prospectively recruited at the National Hospital for Neurology and Neurosurgery (London, United Kingdom) and the Walton Centre (Liverpool, United Kingdom) between 2014 and 2019. They underwent conventional and advanced brain, cord, and optic nerve MRI and optical coherence tomography (OCT).

RESULTS

A total of 91 consecutive patients (31 RRMS, 30 APQ4-NMOSD, and 30 MOGAD) and 34 healthy controls were recruited. The most accurate measures differentiating RRMS from AQP4-NMOSD were the proportion of lesions with the central vein sign (CVS) (84% vs 33%, accuracy/specificity/sensitivity: 91/88/93%, p < 0.001), followed by cortical lesions (median: 2 [range: 1-14] vs 1 [0-1], accuracy/specificity/sensitivity: 84/90/77%, p = 0.002) and white matter lesions (mean: 39.07 [±25.8] vs 9.5 [±14], accuracy/specificity/sensitivity: 78/84/73%, p = 0.001). The combination of higher proportion of CVS, cortical lesions, and optic nerve magnetization transfer ratio reached the highest accuracy in distinguishing RRMS from AQP4-NMOSD (accuracy/specificity/sensitivity: 95/92/97%, p < 0.001). The most accurate measures favoring RRMS over MOGAD were white matter lesions (39.07 [±25.8] vs 1 [±2.3], accuracy/specificity/sensitivity: 94/94/93%, p = 0.006), followed by cortical lesions (2 [1-14] vs 1 [0-1], accuracy/specificity/sensitivity: 84/97/71%, p = 0.004), and retinal nerve fiber layer thickness (RNFL) (mean: 87.54 [±13.83] vs 75.54 [±20.33], accuracy/specificity/sensitivity: 80/79/81%, p = 0.009). Higher cortical lesion number combined with higher RNFL thickness best differentiated RRMS from MOGAD (accuracy/specificity/sensitivity: 84/92/77%, p < 0.001).

DISCUSSION

Cortical lesions, CVS, and optic nerve markers achieve a high accuracy in distinguishing RRMS from APQ4-NMOSD and MOGAD. This information may be useful in clinical practice, especially outside the acute phase and when serologic testing is ambiguous or not promptly available.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that selected conventional and advanced brain, cord, and optic nerve MRI and OCT markers distinguish adult patients with RRMS from AQP4-NMOSD and MOGAD.

A simple and high -performance immobilization technique of membrane protein from crude cell lysate sample for a membrane-based immunoassay application

Membrane proteins are difficult to be extracted and to be coated on the substrate of the immunoassay reaction chamber because of their hydrophobicity. Traditional method to prepare membrane protein sample requires many steps of protein extraction and purification that may lead to protein structure deformation and protein dysfunction. This work proposes a simple technique to prepare and immobilize the membrane protein suspended in an unprocessed crude cell lysate sample. Membrane fractions in crude cell lysate were incorporated with the large unilamellar vesicle (LUV) that was mainly composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) before coating in the polystyrene plate by passive adsorption technique. Immunofluorescence staining and the Enzyme-Linked Immunosorbent Assay (ELISA) examination of a strictly conformation-dependent integral membrane protein, Myelin Oligodendrocyte Glycoprotein (MOG), demonstrate that LUV incorporated cell lysate sample obviously promotes MOG protein immobilization in the microplate well. With LUV incorporation, the dose-response curve of the MOG transfected cell lysate coating plate can be 2-9 times differentiated from that of the untransfected cell lysate coating plate. The LUV incorporated MOG transfected cell lysate can be efficiently coated in the microplate without carbonate/bicarbonate coating buffer assistance.

Efficacy of azathioprine, mycophenolate mofetil, and rituximab in the treatment of neuromyelitis optica spectrum disorder and analysis of prognostic factors

OBJECTIVE

The study aims to compare the efficacies of the immunosuppressants most commonly prescribed for patients with neuromyelitis optica spectrum disorder (NMOSD). The predictors, which might be associated with relapse and disability in NMOSD, were also analyzed.

METHODS

This retrospective study included NMOSD patients treated with azathioprine (AZA), mycophenolate mofetil (MMF), and rituximab (RTX). The annual relapse rate (ARR) and the incidence rates of adverse events were compared. Cox proportional-hazards model calculated the potential predictors of NMOSD relapse and disability.

RESULTS

A total of 83 patients were included. The median treatment time of AZA group (n = 34), MMF group (n = 20), and RTX group (n = 29) were 19.5, 15.5, and 12 months, respectively. ARR of the three groups reduced significantly after treatment. In the three groups, 55.9%, 50%, and 79.3% of patients, respectively, were free from relapse. However, the difference among the three groups was of no statistical significance, possibly due to the small sample size. During the treatment, 32.4%, 15%, and 24.1% of patients experienced adverse events in the AZA group, MMF group, and RTX group, respectively. Additionally, the multivariate Cox analyses indicated that history of a severe attack and disease duration were associated with the risk of relapse after immunotherapy. Late-onset (≥ 50 years old) NMOSD patients were probably more susceptible to motor disability, and those with optic neuritis at onset were more likely to develop visual disability.

CONCLUSIONS

AZA, MMF, and low-dose RTX were all effective in reducing the relapse rate in NMOSD. The age at onset, disease duration, history of severe attacks, and primary syndromes might be significant prognostic predictors in NMOSD.

Current Nosology of Neural Autoantibody-Associated Dementia

Background

The detection of neural autoantibodies in patients with cognitive decline is an increasingly frequent phenomenon in memory clinics, and demanding as it does a specific diagnostic approach and therapeutic management, it deserves greater attention. It is this review’s aim to present the latest nosology of neural autoantibody-associated dementia.

Methods

A specific literature research via PubMed was conducted to describe the nosology of neural autoantibody-associated dementia.

Results

An autoimmune dementia comprises with an early onset, atypical clinical presentation and rapid progression in conjunction with neural antibodies, signs of inflammation in the cerebrospinal fluid, and a non-neurodegenerative pattern in neuroimaging. An autoimmune dementia is probably present if the patient responds to immunotherapy. Atypical dementia involving neural autoantibodies with mostly N-methyl-D-aspartate receptor antibodies might not fulfill all the autoimmune-dementia criteria, thus it may constitute an independent disease entity. Finally, a neurodegenerative dementia such as the frontotemporal type also coincides with neural autoantibodies such as the subunit ionotropic glutamate receptors 3 of amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antibodies, dementia with Lewy bodies with myelin oligodendrocytic protein, myelin basic protein antibodies, or Creutzfeldt-Jakob disease with Zic4 or voltage gated potassium channel antibodies. These dementia entities may well overlap in their clinical features and biomarkers, i.e., their neural autoantibodies or neuroimaging patterns.

Conclusion

There are three main forms of neural autoantibody-associated dementia we can distinguish that might also share certain features in their clinical and laboratory presentation. More research is urgently necessary to improve the diagnosis and therapy of these patients, as the progression of their dementia might thus be improved or even reversed.

Pathogenesis of autoimmune demyelination: from multiple sclerosis to neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease

Autoimmunity plays a significant role in the pathogenesis of demyelination. Multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein antibody‐associated disease (MOGAD) are now recognised as separate disease entities under the amalgam of human central nervous system demyelinating disorders. While these disorders share inherent similarities, investigations into their distinct clinical presentations and lesion pathologies have aided in differential diagnoses and understanding of disease pathogenesis. An interplay of various genetic and environmental factors contributes to each disease, many of which implicate an autoimmune response. The pivotal role of the adaptive immune system has been highlighted by the diagnostic autoantibodies in NMOSD and MOGAD, and the presence of autoreactive lymphocytes in MS lesions. While a number of autoantigens have been proposed in MS, recent emphasis on the contribution of B cells has shed new light on the well‐established understanding of T cell involvement in pathogenesis. This review aims to synthesise the clinical characteristics and pathological findings, discuss existing and emerging hypotheses regarding the aetiology of demyelination and evaluate recent pathogenicity studies involving T cells, B cells, and autoantibodies and their implications in human demyelination.

Frequency of myelin oligodendrocyte glycoprotein antibodies in a large cohort of neurological patients

Background

Myelin oligodendrocyte glycoprotein (MOG) antibody disease (MOG-AD) is recognized as a distinct nosological entity. IgG antibodies against MOG (MOG-Ab) overlap with neuromyelitis optica spectrum disorders (NMOSD) phenotype in adults. However, an increasing number of clinical phenotypes have been reported to be associated with MOG-Ab.

Objective

To investigate the seroprevalence of MOG-Ab under consideration of demographics, disease entities and time course in a large cohort of unselected neurological patients.

Methods

Blood samples of 2.107 consecutive adult neurologic patients admitted to our department between 2016-2017 were tested for MOG-Ab using a cell-based assay. MOG-Ab persistence was analyzed in follow-up samples. External validation was performed in two independent laboratories.

Results

We found MOG-Ab in 25 of 2.107 (1.2%) patients. High antibody ratios were mostly associated with NMOSD and MOG-AD phenotype (5/25). Low ratios occurred in a wide range of neurological diseases, predominantly in other demyelinating CNS diseases (5/25) and stroke (6/25). MOG-Ab persistence over time was not confined to NMOSD and MOG-AD phenotype.

Conclusion

The present study demonstrates the occurrence of MOG-Ab in a wide range of neurological diseases. Only high MOG-Ab ratios were associated with a defined clinical phenotype, but low MOG-Ab ratios were not. The diagnostic value of low MOG-Ab is thus highly limited.

Detection of MOG-IgG in Clinical Samples by Live Cell-Based Assays: Performance of Immunofluorescence Microscopy and Flow Cytometry

Human antibodies against Myelin Oligodendrocyte Glycoprotein (MOG) from immunoglobulin-G subclasses (MOG-IgG) have been recently associated with a new subgroup of neurological autoimmune diseases with distinct clinical characteristics from multiple sclerosis and neuromyelitis optica spectrum disorders. The use of MOG-IgG as a biomarker is an essential tool to assist in the diagnosis and clinical prognosis. The cell-based assay (CBA) is a methodology that expresses high levels of natively folded human MOG protein in the cell membrane being the methodology most used for clinical MOG-IgG diagnosis. However, there is still no consensus about the best approach to perform CBA to improve the results. The CBA using flow cytometry (CBA-FC) is an automated technique with objective quantification, reducing the subject of human bias that occurred at CBA using immunofluorescence (CBA-IF). In this study, we compared the performance of CBA-IF and CBA-FC as an acquisition tool analysis. The sera of 104 patients diagnosed with inflammatory Central Nervous System diseases were tested in both CBA-IF and CBA-FC. We used the dilution of 1:128 for CBA-IF and three different dilutions (1:20, 1:100, and 1:640) for CBA-FC. The CBA-FC and CBA-IF results had 88.5% agreement between assays and the CBA-IF titers by endpoint-dilution correlated with the CBA-FC titers. The highest serum dilution resulted in an increased CBA-FC specificity, but there was a reduction in the CBA-FC sensitivity. Our study showed that CBA-FC can be used in clinical practice as a diagnostic technique for MOG-IgG. In addition, in some specific cases, the combination of both techniques could be used as a tool to discriminate unspecific binding and overcome single assay limitations.