A case of NMO seropositive for aquaporin-4 antibody more than 10 years before onset

Investigation of health care use and a possible prodrome before the first attack in NMOSD and MOGAD

BACKGROUND

Prodromal phases are well recognized in many inflammatory and neurodegenerative diseases, including multiple sclerosis. We evaluated the possibility of a prodrome in aquaporin-4 antibody positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) using health administrative data.

METHODS

We investigated individuals with AQP4 + NMOSD and MOGAD, confirmed by medical chart review, in Ontario, Canada. Each NMOSD and MOGAD participant was matched 1:5 to general population controls by sex, birth year, immigrant status, and region. Total outpatient visits and hospitalizations were compared in the 5 years preceding the incident attack in multivariable negative binomial models.

RESULTS

We identified 96 people with AQP4 + NMOSD, matched to 479 controls, and 61 people with MOGAD, matched to 303 controls. In the 5 years preceding the incident attack, health care use was elevated for outpatient visits and hospitalizations for the NMOSD cohort (adjusted rate ratio (aRR): 1.47; 95% confidence interval (CI): 1.25-1.73; aRR: 1.67; 95% CI: 1.19-2.36, respectively) but not for MOGAD. Rate ratios steadily increased in NMOSD for outpatient visits in the 2 years preceding the incident attack.

CONCLUSION

Our findings support a prodromal phase preceding clinical onset of AQP4 + NMOSD. Earlier recognition and management of NMOSD patients may be possible.

Inhibition of repulsive guidance molecule-a ameliorates compromised blood-spinal cord barrier integrity associated with neuromyelitis optica in rats

The influx of pathogenic aquaporin-4 antibodies (AQP4-Abs) across the blood-spinal cord barrier (BSCB) is crucial for the development and exacerbation of neuromyelitis optica (NMO). We examined whether prophylactic intravenous administration of anti-repulsive guidance molecule-a antibodies (RGMa-Abs) has disease-modifying effects on BSCB dysfunction using an NMO model elicited by peripheral administration of AQP4-Abs to rats. RGMa-Ab treatment attenuated the acute exacerbation of perivascular astrocytopathy in the spinal cord and clinical symptoms, which were highly correlated with neurofilament light chain levels in both the cerebrospinal fluid (CSF) and serum. Additionally, RGMa-Ab treatment suppressed the expression of proinflammatory cytokines/chemokines and the infiltration of inflammatory cells into the spinal cord. CSF analysis of NMO rats revealed that RGMa-Ab treatment improved the CSF/serum albumin ratio and suppressed AQP4-Abs influx. RGMa inhibition using RGMa-Abs is suggested as a potential therapeutic option for BSCB dysfunction associated with NMO.

Cell-binding IgM in CSF is distinctive of multiple sclerosis and targets the iron transporter SCARA5

Intrathecal IgM production in multiple sclerosis is associated with a worse disease course. To investigate pathogenic relevance of autoreactive IgM in multiple sclerosis, CSF from two independent cohorts, including multiple sclerosis patients and controls, were screened for antibody binding to induced pluripotent stem cell-derived neurons and astrocytes, and a panel of CNS-related cell lines. IgM binding to a primitive neuro-ectodermal tumour cell line discriminated 10% of multiple sclerosis donors from controls. Transcriptomes of single IgM producing CSF B cells from patients with cell-binding IgM were sequenced and used to produce recombinant monoclonal antibodies for characterization and antigen identification. We produced five cell-binding recombinant IgM antibodies, of which one, cloned from an HLA-DR + plasma-like B cell, mediated antigen-dependent complement activation. Immunoprecipitation and mass spectrometry, and biochemical and transcriptome analysis of the target cells identified the iron transport scavenger protein SCARA5 as the antigen target of this antibody. Intrathecal injection of a SCARA5 antibody led to an increased T cell infiltration in an experimental autoimmune encephalomyelitis (EAE) model. CSF IgM might contribute to CNS inflammation in multiple sclerosis by binding to cell surface antigens like SCARA5 and activating complement, or by facilitating immune cell migration into the brain.

Prodromes in demyelinating disorders, amyotrophic lateral sclerosis, Parkinson disease, and Alzheimer's dementia

A prodrome is an early set of symptoms, which indicates the onset of a disease; these symptoms are often non-specific. Prodromal phases are now recognized in multiple central nervous system diseases. The depth of understanding of the prodromal phase varies across diseases, being more nascent for multiple sclerosis for example, than for Parkinson disease or Alzheimer's disease. Key challenges when identifying the prodromal phase of a disease include the lack of specificity of prodromal symptoms, and consequent need for accessible and informative biomarkers. Further, heterogeneity of the prodromal phase may be influenced by age, sex, genetics and other poorly understood factors. Nonetheless, recognition that an individual is in the prodromal phase of disease offers the opportunity for earlier diagnosis and with it the opportunity for earlier intervention.

Associations of myeloid cells with cellular and humoral responses following vaccinations in patients with neuroimmunological diseases

Disease-modifying therapies (DMTs) are widely used in neuroimmunological diseases such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). Although these treatments are known to predispose patients to infections and affect their responses to vaccination, little is known about the impact of DMTs on the myeloid cell compartment. In this study, we use mass cytometry to examine DMT-associated changes in the innate immune system in untreated and treated patients with MS (n = 39) or NMOSD (n = 23). We also investigated the association between changes in myeloid cell phenotypes and longitudinal responsiveness to homologous primary, secondary, and tertiary SARS-CoV-2 mRNA vaccinations. Multiple DMT-associated myeloid cell clusters, in particular CD64+HLADRlow granulocytes, showed significant correlations with B and T cell responses induced by vaccination. Our findings suggest the potential role of myeloid cells in cellular and humoral responses following vaccination in DMT-treated patients with neuroimmunological diseases.

Diagnostic implications of MOG-IgG detection in sera and cerebrospinal fluids

The spectrum of MOG-IgG-associated disease (MOGAD) includes optic neuritis (ON), myelitis (MY), acute disseminated encephalomyelitis (ADEM), brainstem encephalitis, cerebral cortical encephalitis (CE) and AQP4-IgG-negative neuromyelitis optica spectrum disorder (NMOSD). In MOGAD, MOG-IgG are usually detected in sera (MOG-IgGSERUM), but there have been some seronegative MOGAD cases with MOG-IgG in CSF (MOG-IgGCSF), and its diagnostic implications remains unclear. In this cross-sectional study, we identified patients with paired serum and CSF sent from all over Japan for testing MOG-IgG. Two investigators blinded to MOG-IgG status classified them into suspected MOGAD (ADEM, CE, NMOSD, ON, MY and Others) or not based on the current recommendations. The MOG-IgGSERUM and MOG-IgGCSF titres were assessed with serial 2-fold dilutions to determine end point titres [≥1:128 in serum and ≥1:1 (no dilution) in CSF were considered positive]. We analysed the relationship between MOG-IgGSERUM, MOG-IgGCSF and the phenotypes with multivariable regression. A total of 671 patients were tested [405 with suspected MOGAD, 99 with multiple sclerosis, 48 with AQP4-IgG-positive NMOSD and 119 with other neurological diseases (OND)] before treatment. In suspected MOGAD, 133 patients (33%) tested MOG-IgG-positive in serum and/or CSF; 94 (23%) double-positive (ADEM 36, CE 15, MY 8, NMOSD 9, ON 15 and Others 11); 17 (4.2%) serum-restricted-positive (ADEM 2, CE 0, MY 3, NMOSD 3, ON 5 and Others 4); and 22 (5.4%) CSF-restricted-positive (ADEM 3, CE 4, MY 6, NMOSD 2, ON 0 and Others 7). None of AQP4-IgG-positive NMOSD, multiple sclerosis or OND cases tested positive for MOG-IgGSERUM, but two with multiple sclerosis cases were MOG-IgGCSF-positive; the specificities of MOG-IgGSERUM and MOG-IgGCSF in suspected MOGAD were 100% [95% confidence interval (CI) 99-100%] and 99% (95% CI 97-100%), respectively. Unlike AQP4-IgG-positive NMOSD, the correlation between MOG-IgGSERUM and MOG-IgGCSF titres in MOGAD was weak. Multivariable regression analyses revealed MOG-IgGSERUM was associated with ON and ADEM, whereas MOG-IgGCSF was associated with ADEM and CE. The number needed to test for MOG-IgGCSF to diagnose one additional MOGAD case was 13.3 (14.3 for ADEM, 2 for CE, 19.5 for NMOSD, infinite for ON, 18.5 for MY and 6.1 for Others). In terms of MOG-IgGSERUM/CSF status, most cases were double-positive while including either serum-restricted (13%) or CSF-restricted (17%) cases. These statuses were independently associated with clinical phenotypes, especially in those with ON in serum and CE in CSF, suggesting pathophysiologic implications and the utility of preferential diagnostic testing. Further studies are warranted to deduce the clinical and pathological significance of compartmentalized MOG-IgG.

Overlap syndrome of anti-aquaporin 4 positive neuromyelitis optica spectrum disorder and primary Sjögren's syndrome: a systematic review of individual patient data

Central nervous system (CNS) involvement can occur in primary Sjögren's syndrome (pSS) due to co-existing neuromyelitis optica spectrum disorder (NMOSD) which has a highly relapsing course requiring indefinite immunosuppression, and if not diagnosed early, damage accrual occurs over time leading to permanent disability and morbidity. In this review, we describe and outline the clinical course and outcomes of anti-aquaporin 4 (AQP4) antibody seropositive NMOSD with pSS overlap cases. To investigate the co-existence of AQP4 + NMOSD with pSS, we conducted a review of individual patient data from case reports and case series found in major databases. The study extracted clinico-demographic features, imaging and laboratory profiles, treatment approaches, and outcomes of these patients. Inclusion criteria for the review required patients to have positivity for anti-AQP4 or NMO-IgG autoantibodies in the blood and/or cerebrospinal fluid (CSF) and exhibit at least one manifestation of both pSS and NMOSD. In this overlap between AQP4 + NMOSD and pSS, 44 patients were included of whom 41 (93.2%) were females. The mean age of pSS onset was 44.8 ± 18.4 years and NMOSD onset was 43.2 ± 19.8 years. In 20 (45.5%) patients, NMOSD preceded pSS onset, 13 (29.5%) NMOSD occurred after pSS onset, and 11 (25%) patients had a simultaneous presentation. 31 (70.5%) patients experienced acute transverse myelitis, 21 (47.7%) optic neuritis, 14 (31.8%) cerebral syndrome, 10 (22.7%) acute brainstem syndrome, 5 (11.4%) area postrema syndrome, and 2 (4.5%) diencephalic clinical syndromes. For the treatment of acute phase, 40 (90.9%) patients received intravenous methylprednisolone, 15 (34.1%) received plasma exchange, and 10 (22.7%) received intravenous immunoglobulin; and for the induction/maintenance therapy, 16 (36.4%) patients received cyclophosphamide, 6 (13.6%) received rituximab, 16 (36.4%) received azathioprine, and 10 (22.7%) received mycophenolate mofetil. Disease course was monophasic in 2 (4.5%) and relapsing in 27 (61.4%) patients. At median (IQR) follow-up duration of 2.4 (6) years, 39 (88.6%) patients showed improvement, 3 (6.8%) showed stabilization and 2 (4.5%) showed worsening of their NMOSD manifestations. In this overlap syndrome of AQP4 + NMOSD and pSS, patients have a neurologically disabling disorder that can mimic neurological manifestations of pSS, frequently occurs prior to the onset of pSS, has a relapsing course, responds well to immunosuppressants, and necessitates indefinite treatment. Collaborative multicentre studies are needed to clarify the natural history and outcomes of this rare overlap syndrome.

Aquaporin-4 Antibody Dynamics and Relapse Risk in Seropositive Neuromyelitis Optica Spectrum Disorder Treated with Immunosuppressants

OBJECTIVE

To investigate aquaporin-4 antibody (AQP4-IgG) dynamics and relapse risk in patients with seropositive neuromyelitis optica spectrum disorder treated with immunosuppressants.

METHODS

This observational cohort study with prospectively collected data included 400 neuromyelitis optica spectrum disorder patients seropositive for AQP4-IgG and treated with immunosuppressants. Serum AQP4-IgG was detected by fixed cell-based assay every 6 months.

RESULTS

After treatment with immunosuppressants, 128 patients became AQP4-IgG seronegative. The median time to become seronegative for 400 patients was 76.4 months (61.4 months, NA). Among those patients with negative change of AQP4-IgG, the mean annualized relapse rate significantly decreased after patients became seronegative (0.20 vs 0.77, p < 0.001), and a positive correlation was observed between time to become seronegative and relapse (OR 1.018, 95% CI 1.001-1.035, p < 0.05). Independent risk factors for AQP4-IgG becoming seronegative were older age at onset, initiation of immunosuppressants at onset, and shorter disease duration before maintenance therapy. Independent risk factors for relapse included younger age (≤46.4 years) at onset, poly-system involvement in the first attack, and unchanged or increased AQP4-IgG titer. The relapse risk was not associated with sex, combination with connective tissue disease, seropositivity for systemic autoimmune antibodies, or incomplete recovery from the first attack.

INTERPRETATION

Patients with younger age at onset, poly-system involvement in the first attack, and unchanged or increased titer of AQP4-IgG are most likely to experience relapse under treatment with immunosuppressants. Time to AQP4-IgG becoming seronegative and change of AQP4-IgG titer may become the surrogate efficacy biomarkers in clinical trials. ANN NEUROL 2023.

A novel association of osmotic demyelination in Sjögren's syndrome prompts revisiting role of aquaporins in CNS demyelinating diseases: A literature review

BACKGROUND

Primary Sjögren's syndrome (SS) is a chronic systemic autoimmune disease with varied neurological manifestations. SS is associated with anti-aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD), a demyelinating autoimmune disorder of the central nervous system (CNS). Intriguingly, there are reports of osmotic demyelinating syndrome (ODS), a supposedly non-inflammatory disorder, in the context of SS and renal tubular acidosis (RTA), both of which are not yet established risk factors for ODS.

METHODS

A literature search was undertaken to identify case reports of ODS in patients with SS. Details of the clinical and laboratory features of these patients were compiled. Additionally, we searched for NMOSD in patients with SS. We looked for co-existing RTA in patients with SS-ODS as well as SS-NMOSD. We also screened for reports of ODS in RTA without underlying SS.

RESULTS & DISCUSSION

We identified 15 patients (all women, median age 40 years) with ODS in SS, and all of these patients had comorbid RTA. There were only three reported cases of ODS in RTA without underlying SS. We identified a total of 67 patients with SS-NMOSD, of whom only 3 (4.5%) had RTA. Hence, unlike NMOSD, the development of ODS in SS requires a prolonged osmotic or electrolyte abnormality caused by the comorbid RTA. The 15 patients with ODS and SS -RTA, showed heterogeneous clinical manifestations and outcomes. The most common symptom was quadriparesis, seen in 14 of the 15 patients. Eleven of the 15 patients had one of the following features, either alone or in combination: worsening of the sensorium, extensor plantar response, dysphagia/dysarthria, and facial palsy. The latter four manifestations were present at the onset in 7 patients and later in the course of the illness in the remaining 4 patients. Ocular palsy was seen in only four of the 15 patients and was a late manifestation. One patient who had extensive long-segment myelitis and subsequent ODS died, but most patients recovered without significant sequelae. None had hyponatremia, while all patients had hypokalemia and/or hypernatremia. Hypokalemia causing nephrogenic diabetes insipidus (NDI) followed by rapid rise in sodium and the resultant osmotic stress could potentially explain the occurrence of ODS in SS-RTA. Aquaporin (AQP) in astrocytes is implicated in ODS, and renal AQP is downregulated in NDI. Antibodies against AQPs are present in some patients with SS. Defective AQP is therefore a common link underlying all the connected diseases, namely SS, NDI, and ODS, raising the possibility of immune-mediated AQP dysfunction in the pathogenesis.

CONCLUSION

The hitherto unreported association between SS-RTA and ODS may implicate SS and/or RTA in the development of ODS. In the setting of SS-RTA, ODS must be suspected when a patient with flaccid quadriparesis does not respond to the correction of potassium or develops additional neurological features along with a rise in sodium. Defective functions of AQPs may be a possible mechanism linking demyelinating CNS lesions, SS, and RTA. Studies evaluating AQP functions and serum antibodies against AQPs in these conditions are warranted.

Upregulated complement receptors correlate with Fc gamma receptor 3A-positive natural killer and natural killer-T cells in neuromyelitis optica spectrum disorder

BACKGROUND AND OBJECTIVES

Inhibition of terminal complement in neuromyelitis optica spectrum disorder (NMOSD) using eculizumab helps prevent relapses, but the exact mechanism of action of the drug remains unclear. Similarly, genetic variants in the Fc Gamma receptor 3A (FCGR3A), also known as CD16, are correlated with outcomes in NMOSD, but the immune cells expressing those CD16 are unknown. We compared CD16 expression on immune cells modulated by complement activity in natural killer (NK) cells and natural killer-T (NKT) cells in NMOSD to disease and normal-healthy controls.

METHODS

Peripheral blood cell (PBMC) samples from 45 patients with NMOSD with aquaporin 4 (AQP4)-IgG, 18 disease controls, and 19 normal controls were analyzed for CD16 expression and complement receptors in vitro.

RESULTS

At baseline, the number of NKT cells was increased in NMOSD (p < 0.001), but the proportion that was CD16 positive was lower compared to normal and disease controls (p = 0.0012). NK cell count was normal, but the ratio that was CD16 positive was also significantly lower (p < 0.001). In both NK cells and NKT cells from NMOSD, C5 complement receptor expression was much higher than normal and disease controls (p < 0.001 for both). We also evaluated activation markers CD69 and CD83, which were also significantly higher in NK and NKT cells from NMOSD patients. FCGR3A p158 V/V genotype group in NMOSD patients showed decreased NK cell proportion with activation, and fewer CD16-expressing NKT cells than the F/F genotype group.

DISCUSSION

Our results support an immunopathogenesis model in which complement pathway activation in NK/NKT cells upregulates CD16 expression that binds to antibody/antigen complexes. In the context of NMOSD, these complement-sensitive cells may be responsible for the escalating autoimmune activity.

Antibody-Positive Neuromyelitis Optica Spectrum Disorder After Second COVID-19 Vaccination: a Case Report

In the era of the COVID-19 pandemic declared in March 2020, widespread vaccination protocols were initiated to mitigate the severity and spread of COVID-19. Although COVID-19 vaccines have been generally considered safe, adverse events post-vaccination have been reported, including the development of demyelinating disease. We report a rare case of de novo aquaporin-4-positive neuromyelitis optica spectrum disorder (NMOSD) in an 80-year-old man following BNT162b SARS-CoV-2 vaccination to raise the awareness of this possible severe adverse event in an older adult. An 80-year-old South Asian man presented 2 days following his second dose of the Pfizer-BioNTech COVID-19 mRNA BNT162b2 vaccine with progressive left-sided leg weakness and numbness resulting in falls. MRI of the spine revealed a longitudinally extensive transverse myelitis from T3–T4 to T9–T10. Serum antibody testing revealed positive aquaporin-4 (AQP4) antibodies. He was diagnosed with AQP4-positive NMOSD and was treated with high-dose intravenous methylprednisolone and plasma exchange with some improvement. He was subsequently treated with mycophenolate mofetil and a slow steroid wean. This case report adds to the existing literature and suggests that COVID-19 vaccinations may trigger de novo NMOSD or NMOSD relapses in some individuals. Although rare, our patient presented with new-onset NMOSD in his 80 s following COVID-19 vaccination. As such, it is relevant to consider AQP4 testing in those presenting with a post-vaccination myelitis, regardless of age. Ongoing vaccine surveillance and research are needed to understand the risk of NMOSD post-COVID-19 vaccinations further.

MOG encephalomyelitis after vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2): case report and comprehensive review of the literature

BACKGROUND

In around 20% of cases, myelin oligodendrocyte glycoprotein (MOG) immunoglobulin (IgG)-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD) first occurs in a postinfectious or postvaccinal setting.

OBJECTIVE

To report a case of MOG-EM with onset after vaccination with the Pfizer BioNTech COVID-19 mRNA vaccine BNT162b2 (Comirnaty®) and to provide a comprehensive review of the epidemiological, clinical, radiological, electrophysiological and laboratory features as well as treatment outcomes of all published patients with SARS-CoV-2 vaccination-associated new-onset MOG-EM.

METHODS

Case report and review of the literature.

RESULTS

In our patient, MOG-IgG-positive (serum 1:1000, mainly IgG1 and IgG2; CSF 1:2; MOG-specific antibody index < 4) unilateral optic neuritis (ON) occurred 10 days after booster vaccination with BNT162b2, which had been preceded by two immunizations with the vector-based Oxford AstraZeneca vaccine ChAdOx1-S/ChAdOx1-nCoV-19 (AZD1222). High-dose steroid treatment with oral tapering resulted in complete recovery. Overall, 20 cases of SARS-CoV2 vaccination-associated MOG-EM were analysed (median age at onset 43.5 years, range 28-68; female to male ratio = 1:1.2). All cases occurred in adults and almost all after immunization with ChAdOx1-S/ChAdOx1 nCoV-19 (median interval 13 days, range 7-32), mostly after the first dose. In 70% of patients, more than one CNS region (spinal cord, brainstem, supratentorial brain, optic nerve) was affected at onset, in contrast to a much lower rate in conventional MOG-EM in adults, in which isolated ON is predominant at onset and ADEM-like phenotypes are rare. The cerebrospinal fluid white cell count (WCC) exceeded 100 cells/μl in 5/14 (36%) patients with available data (median peak WCC 58 cells/μl in those with pleocytosis; range 6-720). Severe disease with tetraparesis, paraplegia, functional blindness, brainstem involvement and/or bladder/bowel dysfunction and a high lesion load was common, and treatment escalation with plasma exchange (N = 9) and/or prolonged IVMP therapy was required in 50% of cases. Complete or partial recovery was achieved in the majority of patients, but residual symptoms were significant in some. MOG-IgG remained detectable in 7/7 cases after 3 or 6 months.

CONCLUSIONS

MOG-EM with postvaccinal onset was mostly observed after vaccination with ChAdOx1-S/ChAdOx1 nCoV-19. Attack severity was often high at onset. Escalation of immunotherapy was frequently required. MOG-IgG persisted in the long term.

MOG Antibody-Associated Disorders Following SARS-CoV-2 Vaccination: A Case Report and Literature Review

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disorder (MOGAD) is a newly identified autoimmune demyelinating disorder that is often associated with acute disseminated encephalomyelitis and usually occurs postinfection or postvaccination. Here we report a case of MOGAD after mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. A previously healthy 68-year-old woman presented to our department with gradually worsening numbness on the right side of her face, which began 14 days after her second dose of an mRNA-1273 vaccination. The patient's brain MRI revealed a right cerebellar peduncle lesion with gadolinium enhancement, a typical finding of MOGAD. A neurological examination revealed paresthesia on her right V2 and V3 areas. Other neurological examinations were unremarkable. Laboratory workups were positive for serum MOG-IgG as assessed by live cell-based assays and the presence of oligoclonal bands in the cerebrospinal fluid (CSF). The patient's serum test results for cytoplasmic-antineutrophil cytoplasmic antibodies, perinuclear-cytoplasmic-antineutrophil cytoplasmic antibodies, GQ1b-antibodies, and aquaporin-4 antibodies (AQP4-IgG) were all negative. Tests for soluble interleukin (IL)-2 receptors in the serum, IL-6 in the CSF and skin pricks, and angiotensin converting enzyme tests were all unremarkable. The patient was diagnosed with MOGAD after receiving an mRNA SARS-CoV-2 vaccination. After two courses of intravenous methylprednisolone treatment, the patient's symptoms improved and her cerebellar peduncle lesion shrunk slightly without gadolinium enhancement. To date, there have only been two cases of monophasic MOGAD following SARS-CoV-2 vaccination, including both the ChAdOx1 nCOV-19 and mRNA-1273 vaccines, and the prognosis is generally similar to other typical MOGAD cases. Although the appearance of MOG antibodies is relatively rare in post-COVID-19-vaccine demyelinating diseases, MOGAD should be considered in patients with central nervous system (CNS) demyelinating diseases after receiving a SARS-CoV-2 vaccine.

Cells to the Rescue: Emerging Cell-Based Treatment Approaches for NMOSD and MOGAD

Cell-based therapies are gaining momentum as promising treatments for rare neurological autoimmune diseases, including neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease. The development of targeted cell therapies is hampered by the lack of adequate animal models that mirror the human disease. Most cell-based treatments, including HSCT, CAR-T cell, tolerogenic dendritic cell and mesenchymal stem cell treatment have entered early stage clinical trials or have been used as rescue treatment in treatment-refractory cases. The development of antigen-specific cell-based immunotherapies for autoimmune diseases is slowed down by the rarity of the diseases, the lack of surrogate outcomes and biomarkers that are able to predict long-term outcomes and/or therapy effectiveness as well as challenges in the manufacturing of cellular products. These challenges are likely to be overcome by future research.

Dynamic Changes in AQP4-IgG Level and Immunological Markers During Protein-A Immunoadsorption Therapy for NMOSD: A Case Report and Literature Review

The changes in the serum levels of aquaporin-4-IgG (AQP4-IgG), immunoglobulins, and inflammatory mediators in neuromyelitis optica spectrum disorder (NMOSD) cases treated with immunoadsorption have been rarely described in detail. Here we report a 29-year-old steroid-resistant NMOSD female with a severe disability (bilateral blindness and paraplegia) who received protein-A immunoadsorption as a rescue treatment. During the total 5 sessions, the circulating level of AQP4-IgG, immunoglobulins, and complement proteins (C3 and C4) showed a rapid and sawtooth-like decrease, and the serum AQP4-IgG titer declined from 1:320 to below the detectable limit at the end of the 3rd procedure. Of all the antibodies, IgG had the biggest removal rate (>96.1%), followed by IgM (>66.7%) and IgA (53%), while complement C3 and C4 also dropped by 73% and 65%, respectively. The reduced pro-inflammatory cytokines (interleukin-8 and tumor necrosis factor-α) and marked increased lymphocyte (T and B cell) counts were also observed. The improvement of symptoms initiated after the last session, with a low AQP4-IgG titer (1:32) persisting thereafter. Accordingly, protein-A immunoadsorption treatment could be one of the potential rescue therapies for steroid-resistant NMOSD patients with a severe disability.

Optic neuritis after ocular trauma in anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder

OBJECTIVE

The aim of this study was to report the possible association between minor trauma to the eyes and the subsequent occurrence of optic neuritis in patients with serum anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD).

METHODS

Herein, we present three patients who developed acute optic neuritis with visual disturbances after accidental minor trauma to their eyes, without any fundus abnormality or orbital floor fractures present.

RESULTS

Two of the three patients had a preceding history of neurological disturbances compatible with NMOSD (e.g., myelitis, area postrema syndrome) before the occurrence of trauma. One patient was rapidly treated with steroid pulse therapy and plasmapheresis, and he fully recovered visual acuity. The other two, who were left untreated in the acute phase, had sequelae of severe visual disturbances in the affected eyes.

CONCLUSIONS

These cases suggest possible association between minor trauma to the eyes and the subsequent occurrence of optic neuritis in patients with serum anti-AQP4 antibodies. Avoiding ocular trauma and early administration of steroid pulse therapy in response to optic neuritis after trauma are desired in such cases.

Sporadic amyotrophic lateral sclerosis with seropositive neuromyelitis optica spectrum disorder: A case report

RATIONALE

Neuromyelitis optica spectrum disorder (NMOSD) is a severe inflammatory disorder of the central nervous system with an autoantibody against aquaporin-4 protein (AQP4), and amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. We report a female patient with ALS who had asymptomatic AQP4 antibody at the diagnosis of ALS, and NMOSD occurred 4 years later after the diagnosis of ALS.

PATIENT CONCERNS

She was already bedridden and had tracheostomy because of ALS which was diagnosed at her age of 55. At the time of her ALS diagnosis, she had no brain or spinal cord lesions, but was seropositive for AQP4 antibody. At her age of 59, new-onset complete paralysis of all extremities and severe pain on the posterior neck and both shoulders occurred and visited the hospital.

DIAGNOSIS

Longitudinally extensive transverse myelitis was diagnosed, which was the onset attack of seropositive NMOSD. The diagnosis was confirmed based on the international consensus diagnostic criteria for NMOSD with MR imaging, cerebrospinal fluid exam and laboratory work-ups with AQP4 antibody test.

INTERVENTIONS

High dose methylprednisolone was administered for 5 days. Plasma exchange as a further treatment was recommended, but she and her family refused.

OUTCOMES

Her pain was relieved after steroid treatment, but there was no improvement of her leg weakness.

LESSONS

This case is a rare combination of neuroinflammatory and neurodegenerative diseases. Considering the alterations of blood-brain barrier along with the progression of ALS, it highlights that the consequence of ALS pathogenesis might affect the development of NMOSD. And the careful follow-up is recommended even in patients with profound weakness, especially if those who were at risk of developing certain neurological disorders.

Recent Advances in Neuromyelitis Optica Spectrum Disorder: Pathogenesis, Mechanisms and Potential Treatments

Neuromyelitis optica spectrum disorder (NMOSD) is an acute or subacute demyelinating disease that affects mainly the optic nerve and spinal cord. A major proportion of NMOSD cases have a relationship with autoimmunity to aquaporin 4 (AQP4) found on the central nervous system. NMOSD can occur repeatedly, causing symptoms such as decreased vision and weakness of limbs. The main goal of current therapy is to relieve acute symptoms and prevent recurrence of the disease. Without timely and appropriate treatment, the recurrence and disability rates are high. In the present work, we review recent advances in the diagnosis and treatment of patients with NMOSD, as well as the pathogenesis and mechanisms of AQP4-IgG-seropositive NMOSD.

Blood-brain barrier resealing in neuromyelitis optica occurs independently of astrocyte regeneration

Approximately 80% of neuromyelitis optica spectrum disorder (NMOSD) patients harbor serum anti-aquaporin-4 autoantibodies targeting astrocytes in the CNS. Crucial for NMOSD lesion initiation is disruption of the blood-brain barrier (BBB), which allows the entrance of Abs and serum complement into the CNS and which is a target for new NMOSD therapies. Astrocytes have important functions in BBB maintenance; however, the influence of their loss and the role of immune cell infiltration on BBB permeability in NMOSD have not yet been investigated. Using an experimental model of targeted NMOSD lesions in rats, we demonstrate that astrocyte destruction coincides with a transient disruption of the BBB and a selective loss of occludin from tight junctions. It is noteworthy that BBB integrity is reestablished before astrocytes repopulate. Rather than persistent astrocyte loss, polymorphonuclear leukocytes (PMNs) are the main mediators of BBB disruption, and their depletion preserves BBB integrity and prevents astrocyte loss. Inhibition of PMN chemoattraction, activation, and proteolytic function reduces lesion size. In summary, our data support a crucial role for PMNs in BBB disruption and NMOSD lesion development, rendering their recruitment and activation promising therapeutic targets.

Systemic cellular immunity and neuroinflammation during acute flare-up in multiple sclerosis and neuromyelitis optica spectrum disorder patients

Twenty-seven treatment-naïve patients with relapsing-remitting multiple sclerosis (MS) and 13 with neuromyelitis optica spectrum disorder (NMOSD) were enrolled during a time of acute flare-up. Common cerebrospinal fluid (CSF) features were increased CD29- and/or CD45RO-positive helper T cells capable of propagating inflammation in the central nervous system (CNS). B cell activation in the CSF was unique to MS, while an increase in CD4⁺CD192 (CCR2)⁺ cells in blood and breakdown of the blood-brain barrier (BBB) characterized NMOSD. Intravenous corticosteroid therapy suppressed neuroinflammation via modulation of cellular immunity in MS, as opposed to restoration of the BBB in NMOSD.

[A case of spinal cord infarction accompanied with neuromyelitis optica spectrum pathophysiology]

We report a 60-year-old woman who developed spinal cord infarction (SCI) with anti-aquaporin (AQP) 4 antibody seropositive. She was admitted to our hospital with acute onset of flaccid paraparesis and urinary disturbances that completed within a few minutes after acute pain in her lower back. Neurological examination revealed flaccid paraparesis, bladder and bowel dysfunction and dissociated sensory loss below the level of Th11 spinal cord segment. Diffusion weighted imaging (DWI) and T₂-wighted imaging (T₂WI) of thoracic spine MRI showed high signal intensity in the spinal cord between Th9 and Th12 vertebral levels with decreased apparent diffusion coefficient (ADC). We diagnosed her as having SCI. Thereafter the serum examination on admission was reported as positive for anti-aquaporin 4 (AQP4) antibody. Cerebrospinal fluid (CSF) analysis revealed pleocytosis, and the spinal cord lesions became enlarged in MRI on 12 days after the onset. We, therefore, suspected that the pathophysiology of neuromyelitis optica spectrum disorder (NMOSD) accompanied SCI. The patient underwent two courses of high dose intravenous methylprednisolone (IVMP) for three days (1 g/day). Her neurological symptoms did not improve significantly, but the size of T₂WI MRI high signal lesion improved to that of the initial MRI scan. Anti-AQP4 antibody seropositivity may have modified the SCI pathology in the present patient.

Herpes Zoster Radiculomyelitis With Aquaporin-4 Antibodies: A Case Report and Literature Review

Background: The relationship between varicella-zoster virus (VZV)-associated myelitis and aquaporin-4 immunoglobulin-G (AQP4-IgG) remains unknown.

Case Report: We report a case of acute radiculomyelitis with longitudinal extensive hyperintensity signals traversing the brainstem until the upper thoracic cord in a 55-year-old healthy woman following herpes zoster infection in the left C4-T3 dermatome. VZV-specific IgG in the cerebrospinal fluid (CSF) and AQP4-IgG positivity on enzyme-linked immunosorbent assay (ELISA) were undetectable. Thus, she was diagnosed with immune-competent VZV radiculomyelitis. Forty-two months later, she experienced a relapse, and AQP4-IgG positivity was detected on ELISA. A cell-based assay (CBA) showed AQP4-IgG positivity not only at the time of recurrence but also retrospectively at 1 month after the initial symptoms. We concluded that AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) was concurrent with VZV myelitis. After the second attack, she was treated with azathioprine and has had no relapse since then.

Conclusion: We reported a case of VZV radiculomyelitis with confirmed concurrent AQP4-IgG positivity. NMOSD induced by herpes zoster has been recently identified, but distinguishing it from VZV myelitis can be difficult and whether these two diseases aggravate each other is unknown. Awareness of the potentially varied presentation of VZV myelitis can enable earlier recognition and proper treatment.

A case of area postrema variant of neuromyelitis optica spectrum disorder following SARS-CoV-2 infection

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune astrocytopathic channelopathy, characterized by the presence of pathogenic antibodies to aquaporin-4 (AQP-4) water channels. Several viral infections including HIV, influenza virus, varicella zoster virus, and Epstein Barr virus, among others, have been alleged to trigger NMOSD in both immunocompetent and immunocompromised individuals. Neurological manifestations of coronavirus infectious disease of 2019 (COVID-19) have been ever evolving and the spectrum of neuraxial involvement is broadening. Albeit it may affect any area of the neural axis, the involvement of the spinal cord is rare compared to that of the brain and of the peripheral nervous system. Cases with acute longitudinally extensive transverse myelitis (LETM) have been recently reported in SARS-CoV-2 infection but did not fulfill the international consensus diagnostic criteria for NMOSD. AQP-4-antibody-seropositive NMOSD following SARS-CoV-2 infection had not yet been reported. We herein report a novel case of a previously healthy man who presented with a clinical picture of bouts of vomiting and hiccoughs (area postrema syndrome), which rapidly evolved to acute LETM, all following SARS-CoV-2 infection. He was finally diagnosed to be a case of seropositive NMOSD which presented as area postrema syndrome. The response to immunomodulatory drugs was excellent.

Recurrent optic neuritis in a patient with Sjogren syndrome and neuromyelitis optica spectrum disorder: A case report

RATIONALE

Neuromyelitis optica spectrum disorder (NMOSD) patients, especially those with anti-aquaporin-4 antibody positivity, a water channel expressed on astrocytes, is often accompanied by autoimmune diseases (ADs) including Sjogren syndrome (SS). Here, we report a case of a young Chinese woman with recurrent optic neuritis who was diagnosed with asymptomatic SS and NMOSD.

PATIENT CONCERNS

A 22-year-old Chinese woman suffered from optic neuritis for 3 years. The main manifestation was recurrent loss of vision. The anti-aquaporin-4 antibody was positive in the cerebrospinal fluid, and she was diagnosed with NMOSD. Other laboratory tests revealed positive anti-SSA and anti-SSB antibodies, and labial gland biopsy showed lymphocytic infiltration. She also fulfilled the international criteria for SS.

DIAGNOSIS

On the basis of recurrent vision loss and laboratory examination, we defined the patient with SS accompanied by NMOSD.

INTERVENTIONS

When the patient first experienced vision loss, the corticosteroid treatment in the external hospital was effective, and her visual acuity improved significantly. However, in several later attacks, such treatment was no longer obviously effective. Considering the patient's condition, she was treated with corticosteroids, cyclophosphamide, and immunoglobulin therapy on admission.

OUTCOMES

The patient's visual acuity was increased to the right eye 20/800 and left eye finger counting when she was discharged from the hospital.

LESSONS

SS accompanied with NMOSD is common in clinical practice, and always with the positive Anti-AQP4 antibody as a potential biomarker. Patients with SS and NMOSD showed significant neurological symptoms and had a worse prognosis than SS patients with negative anti-AQP4 antibody because of cross-immunity between anti-SSA antibody and anti-AQP4 antibody. Rheumatologists and ophthalmologists should pay attention to this and perform appropriate tests.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

Induction of aquaporin 4-reactive antibodies in Lewis rats immunized with aquaporin 4 mimotopes

Most cases of neuromyelitis optica spectrum disorders (NMOSD) harbor pathogenic autoantibodies against the water channel aquaporin 4 (AQP4). Binding of these antibodies to AQP4 on astrocytes initiates damage to these cells, which culminates in the formation of large tissue destructive lesions in the central nervous system (CNS). Consequently, untreated patients may become permanently blind or paralyzed. Studies on the induction and breakage of tolerance to AQP4 could be of great benefit for NMOSD patients. So far, however, all attempts to create suitable animal models by active sensitization have failed. We addressed this challenge and identified peptides, which mimic the conformational AQP4 epitopes recognized by pathogenic antibodies of NMOSD patients. Here we show that these mimotopes can induce the production of AQP4-reactive antibodies in Lewis rats. Hence, our results provide a conceptual framework for the formation of such antibodies in NMOSD patients, and aid to improve immunization strategies for the creation of animal models suitable for tolerance studies in this devastating disease.

Risk factors of attacks in neuromyelitis optica spectrum disorders

Predisposing factors before the onset of neuromyelitis optica spectrum disorders (NMOSD) have not been systematically evaluated by now. We investigated the detailed pre-onset history in consecutive NMOSD patients. Thirteen of the enrolled 53 NMOSD patients (24.5%) had accompanying autoimmune diseases, such as Sjögren's syndrome. History of malignancy was seen in 8 of the 53 patients (15.1%). Recent history of non-neurological clinical episodes, such as systemic allergic reaction, systemic infection, surgical operation, or traumatic injury, was seen in 23 of the 53 patients (43.4%). NMOSD patients are likely to have pre-onset history of other autoimmune diseases, malignancy, or recent non-neurological systemic conditions, which may predispose or trigger the onset of NMOSD.

Association of antibodies against myelin and neuronal antigens with neuroinflammation in systemic lupus erythematosus

OBJECTIVES

To determine frequency and syndrome specificity of novel and known nervous system (NS)-directed antibodies in a large, unbiased cohort of SLE patients in the Swiss SLE Cohort Study.

METHODS

This retrospective pilot study included 174 patients in a cross-sectional and 102 in a longitudinal study. Antibodies against 12 NS antigens [myelin oligodendrocyte glycoprotein (MOG), neurofascin 186 (NF186), aquaporin-4 (AQP4), N-methyl-D-aspartate receptor (subunit NR1) (NMDAR-NR1), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (subunits 1 and 2) (AMPAR1/2), gamma-aminobutyric acid B receptor (subunits B1 and B2) (GABABR1/2), glutamate decarboxylase 65 (GAD65), glycine receptor (GlyR), contactin-associated protein-like 2 (CASPR2), leucine-rich glioma-inactivated 1 (LGI1), metabotropic glutamate receptor 5 (mGluR5) and dipeptidyl-peptidase-like protein 6 (DPPX)] were screened with validated cell-based assays and correlated with clinical and diagnostic findings.

RESULTS

Twenty-three of one hundred and seventy-four (13.2%) patients harboured antibodies against MOG (n = 14), NF186 (n = 6), GAD65 (n = 2), AQP4 and GlyR (n = 1). Anti-MOG antibodies were most frequently found in the cohort (8%). Thirteen of the anti-NS antibody-positive patients showed clinical symptoms of NS involvement, a subgroup of which (n = 8) resembled the syndrome associated with the antibody. Nine patients harboured antibodies without neurological symptoms and one patient was lost to follow-up. The frequency of NPSLE was significantly higher in the anti-NS antibody-positive patients (13/23, 56.5%: MOG 6/14, 42.9%; NF186 5/6, 83.3%; GAD65 2/2, 100%; AQP4/GlyR 0/1, 0%) compared with the antibody-negative cohort (21/151, 13.9%) (chi-square test, P < 0.0001).

CONCLUSION

Anti-NS antibodies, most prevalently anti-MOG antibodies, are significantly associated with NPSLE and manifest with the distinct neurological syndrome associated with the antibody in a subgroup. Follow-up studies in large, independent cohorts will reveal whether these anti-NS antibodies could serve as a diagnostic and prognostic biomarker for NPSLE and enable tailored treatment decisions in this challenging and diverse patient cohort.

Neuromyelitis optica spectrum disorder with massive basal ganglia involvement: a case report

BACKGROUND

Occurrence of basal ganglia involvement in neuromyelitis optica spectrum disorders (NMOSD) has rarely been reported and none documented pathologically.

CASE PRESENTATION

A 73-year-old female was clinically diagnosed with a NMOSD based on the clinical and radiological features and positive serum autoantibodies to AQP4. One month before her death, she became acutely ill with disturbed consciousness and right hemiparesis, and was diagnosed and treated as having basal ganglia infarction based on the brain CT. She made a partial recovery but later died from heart failure. At autopsy, the corresponding basal ganglia process revealed a large fresh area of necrosis. Histologically, several pathological signatures of NMOSD could be recognized in the lesion, including inflammatory cell infiltrations by B and T lymphocytes, perivascular complement and fibrinogen deposition, and the appearance of numerous phagocytosed corpora amylacea within the infiltrating macrophages.

CONCLUSIONS

The present case illustrates that basal ganglia may be directly involved in the pathological processes of NMOSD, although the possibility of modification of the lesions by superimposed regional ischemia could not be excluded.

The clinical value of the albumin quotient in patients with neuromyelitis optica spectrum disorder

BACKGROUND

The disruption of the blood-brain barrier (BBB) is common in patients with neuromyelitis optica spectrum disorder (NMOSD), causing pro-inflammatory immune cells to migrate into the central nervous system (CNS) and active demyelinating lesions. Albumin quotient is commonly used as an indicator for BBB permeability or dysfunction, but its potential clinical value in NMOSD treatment has never been explored. The present study investigated the differences in the albumin quotient level among NMOSD patients with different antibodies (AQP4-IgG and MOG-IgG) and the relationship between the albumin quotient and neurological dysfunction.

METHODS

We retrospectively collected data from 141 patients with NMOSD (104 with AQP4-IgG and 37 with MOG-IgG) and reviewed their clinical features and albumin quotient levels.

RESULTS

The percentage of patients with an abnormal albumin quotient was significantly higher in the MOG-IgG group than in the AQP4-IgG group (48.6% vs 27.9%, P = 0.026); albumin quotient levels in the AQP4-IgG-positive group were similar to those in the MOG-IgG groups (5.65 vs 5.8, P = 0.23). Among those with an abnormal quotient, no differences in the proportions of severe neurological disability across treatment were found between patients with AQP4-IgG and those with MOG-IgG (pre-treatment: AQP4-IgG group vs MOG-IgG group: 58.6% vs 38.9%, P = 0.24; post-treatment: AQP4-IgG group vs MOG-IgG group: 31.0% vs 22.2%, P = 0.74).

CONCLUSIONS

The BBB breakdown in NMOSD patients with MOG-IgG may be more common than in those with AQP4-IgG. AQP4-IgG-positive patients and MOG-IgG-positive patients with severe neurological disability tend to exhibit similar disruptions to the BBB.

Noninvasive, Targeted Creation of Neuromyelitis Optica Pathology in AQP4-IgG Seropositive Rats by Pulsed Focused Ultrasound

Neuromyelitis optica spectrum disorders (herein called NMO) is an autoimmune disease of the CNS characterized by astrocyte injury, inflammation, and demyelination. In seropositive NMO, immunoglobulin G autoantibodies against aquaporin-4 (AQP4-IgG) cause primary astrocyte injury. A passive transfer model of NMO was developed in which spatially targeted access of AQP4-IgG into the CNS of seropositive rats was accomplished by pulsed focused ultrasound through intact skin. Following intravenous administration of microbubbles, pulsed ultrasound at 0.5 MPa peak acoustic pressure was applied using a 1 MHz transducer with 6-cm focal length. In brain, the transient opening of the blood-brain barrier (BBB) in an approximately prolate ellipsoidal volume of diameter ∼3.5 mm and length ∼44 mm allowed entry of IgG-size molecules for up to 3-6 hours. The ultrasound treatment did not cause erythrocyte extravasation or inflammation. Ultrasound treatment in AQP4-IgG seropositive rats produced localized NMO pathology in brain, with characteristic astrocyte injury, inflammation, and demyelination after 5 days. Pathology was not seen when complement was inhibited, when non-NMO human IgG was administered instead of AQP4-IgG, or in AQP4-IgG seropositive AQP4 knockout rats. NMO pathology was similarly created in cervical spinal cord in seropositive rats. These results establish a noninvasive, spatially targeted model of NMO in rats, and demonstrate that BBB permeabilization, without underlying injury or inflammation, is sufficient to create NMO pathology in AQP4-IgG seropositive rats.

Low Serum Interleukin-10 Is an Independent Predictive Factor for the Risk of Second Event in Clinically Isolated Syndromes

Objective: To evaluated the prognostic ability of several serum cytokines in clinically isolated syndrome (CIS) patients regarding second events and conversion to multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD). Methods: We enrolled 69 CIS patients whose serum samples were collected during the acute phase of the first onset before immunotherapy. Fifteen other non-inflammatory neurological disorder (OND) patients were also included. The serum levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-13, IL-17A, IL-21, IL-23, interferon-γ (IFN-γ), and transforming growth factor beta 1 (TGF-β1) were measured using the human cytokine multiplex assay or ELISA. Patients were seen every 3-6 months. Unscheduled visits occur in case of exacerbations. Clinical measures of disease progression were recorded. Results: Twenty CIS cases had second events during follow-up at a mean time of 15.3 ± 9.9 months. Serum IL-10 levels were significantly lower in CIS patients who relapsed compared to patients who did not. Low serum IL-10 levels were associated with higher risk and shorter times to second events. In clinical correlations, a significantly higher CSF white blood cells count, number of T2 lesions, and gadolinium-enhancing (Gd+) lesions in baseline MRI were found in the low serum IL-10 level group. Of the 20 relapsed cases, seven converted to MS, and eight converted to NMOSD. No significant differences were found in any cytokine levels between these patients at first onset. Conclusions: These findings support using serum IL-10 as a biomarker associated with the risk of relapse and the time to second events in patients with CIS. However, serum cytokine levels can not differentiate between the conversion from CIS to MS or NMOSD.

Neuromyelitis optic with positive Anti-AQP4 and Anti-SSA/Ro antibody

Neuromyelitis Optic (NMO) is an inflammatory disorder involving central nervous system which often co-exists with other autoimmune diseases such as Sjögren’s syndrome (SS). NMO manifestation could precede or follow SS, but the role of anti-SSA in the pathogenesis of NMO remains unclear. We present a case of NMO with anti-AQP4 anti-SSA antibody positive. A-44-year-old female presented with right side weakness. The symptoms began with numbness that improved spontaneously. She also complained pain and dry sensations on her eyes. Schirmer test on her left eye, antinuclear antibody (ANA) and anti-SSA antibody were positive. Cervical MRI revealed intramedullary lesion on T2-weighted-image at C2-C5 level. She was diagnosed as NMO with positive anti-AQP4 and probable SS. She received 1g methylprednisolone for 5 days proceeded with mycophenolic acid. One-year observation showed clinical improvement. Systemic autoantibodies must substansially be evaluated in NMO. Comprehensive diagnosis and providing appropriate immuno-suppressant might prevent further disability and relapse.

Mechanisms for lesion localization in neuromyelitis optica spectrum disorders

Purpose of review

Neuromyelitis optica spectrum disorders (NMOSD) are severe inflammatory diseases of the central nervous system (CNS), with the presence of aquaporin 4 (AQP4)-specific serum antibodies in the vast majority of patients, and with the presence of myelin oligodendrocyte glycoprotein (MOG)-specific antibodies in approximately 40% of all AQP4-antibody negative NMOSD patients. Despite differences in antigen recognition, the preferred sites of lesions are similar in both groups of patients: They localize to the spinal cord and to the anterior visual pathway including retina, optic nerves, chiasm, and optic tracts, and – to lesser extent – also to certain predilection sites in the brain.

Recent findings

The involvement of T cells in the formation of NMOSD lesions has been challenged for quite some time. However, several recent findings demonstrate the key role of T cells for lesion formation and localization. Studies on the evolution of lesions in the spinal cord of NMOSD patients revealed a striking similarity of early NMOSD lesions with those observed in corresponding T-cell-induced animal models, both in lesion formation and in lesion localization. Studies on retinal abnormalities in NMOSD patients and corresponding animals revealed the importance of T cells for the very early stages of retinal lesions which eventually culminate in damage to Müller cells and to the retinal nerve fiber layer. Finally, a study on cerebrospinal fluid (CSF) barrier pathology demonstrated that NMOSD immunopathology extends beyond perivascular astrocytic foot processes to include the pia, the ependyma, and the choroid plexus, and that diffusion of antibodies from the CSF could further influence lesion formation in NMOSD patients.

Summary

The pathological changes observed in AQP4-antibody positive and MOG-antibody positive NMOSD patients are strikingly similar to those found in corresponding animal models, and many mechanisms which determine lesion localization in experimental animals seem to closely reflect the human situation.

Autoantibodies against Neurologic Antigens in Nonneurologic Autoimmunity

The aim of this study was to test whether autoantibodies against neurologic surface Ags are found in nonneurologic autoimmune diseases, indicating a broader loss of tolerance. Patient and matched healthy donor (HD) sera were derived from four large cohorts: 1) rheumatoid arthritis (RA) (n = 194, HD n = 64), 2) type 1 diabetes (T1D) (n = 200, HD n = 200), 3) systemic lupus erythematosus (SLE) (n = 200, HD n = 67; neuro-SLE n = 49, HD n = 33), and 4) a control cohort of neurologic autoimmunity (relapsing-remitting multiple sclerosis [MS] n = 110, HD n = 110; primary progressive MS n = 9; secondary progressive MS n = 10; neuromyelitis optica spectrum disorders n = 15; and other neurologic disorders n = 26). Screening of 1287 unique serum samples against four neurologic surface Ags (myelin oligodendrocyte glycoprotein, aquaporin 4, acetylcholine receptor, and muscle-specific kinase) was performed with live cell–based immunofluorescence assays using flow cytometry. Positive samples identified in the screening were further validated using autoantibody titer quantification by serial dilutions or radioimmunoassay. Autoantibodies against neurologic surface Ags were not observed in RA and T1D patients, whereas SLE patients harbored such autoantibodies in rare cases (2/200, 1%). Within the CNS autoimmunity control cohort, autoantibodies against aquaporin 4 and high-titer Abs against myelin oligodendrocyte glycoprotein were, as expected, specific for neuromyelitis optica spectrum disorders. We conclude that neurologic autoantibodies do not cross disease barriers in RA and T1D. The finding of mildly increased neurologic autoantibodies in SLE may be consistent with a broader loss of B cell tolerance in this form of systemic autoimmunity.

NEUROMYELITIS OPTICA SPECTRUM DISORDERS: DIAGNOSIS AND TREATMENT, THE EXPERIENCE OF CLINICAL OBSERVATIONS

Neuromyelitis optica spectrum disorder (NMOSD) is an aggregate of inflammatory and autoimmune disorders of the central nervous system characterized by recurrent, disabling clinical course and damages predominantly targeting optic nerves, brain stem and spinal cord. NMOSD is stratified into two types: seropositive for aquaporin-4 antibodies (AQP4-IgG) and seronegative, which is reported in 25 % of cases. This article presents modern conceptualizations of NMOSD and describes authors’ own experience of clinical observation of patients.

[Clinical analysis of opticospinal multiple sclerosis (OSMS) presentation detecting anti-myelin oligodendrocyte glycoprotein (MOG) antibody]

We report an 18 year-old-male, who had been aware of decreased visual acuity for 6 months, newly presented with paresis and sensory disturbance in his right leg. On admission, his critical flicker frequency was reduced bilaterally, and his spinal cord MRI revealed T₂-hyperintense lesions in cervical and thoracic cord with occasional contrast enhancements, but none of them were longitudinally extensive. There was no evidence of T₂-hyperintense in his brain MRI. Anti-aquapolin-4 (AQP4) antibody was negative but the patient was positive for oligoclonal bands in his cerebrospinal fluid. The patient was tentatively diagnosed as opticospinal multiple sclerosis (OSMS). However, he later tuned out to be positive for anti-myelin oligodendrocyte glycoprotein (MOG) antibody. The 2017 revised McDonald criteria don't take anti-MOG antibody into account in detail as to how clinicians should deal with patients fulfilling the MS criteria when they were also positive for anti-MOG antibody, because of its difficult problem of independence. So, we need to accumulate knowledge about these cases.

Obstetric outcomes in a Mexican cohort of patients with AQP4-antibody-seropositive neuromyelitis optica

BACKGROUND

Previous studies have investigated the influence of neuromyelitis optica (NMO) on pregnancy in other ethnic groups. However, there are potential variations among ethnic groups. The obstetric outcome of Mexican patients with NMO and AQP4-IgG positivity (AQP4-IgG[+]) is currently unknown.

OBJECTIVE

To describe the obstetric history of Mexican patients with NMO and AQP4-IgG(+).

METHODS

Patients with NMO and AQP4-IgG(+) were identified from the database of the Demyelinating Diseases Clinic. These patients were interviewed by telephone.

RESULTS

Out of a total of 40 eligible patients, 29 were contacted and completed the survey. Of these, 19 patients reported at least one previous pregnancy. In total, 50 pregnancies were reported: 44 of them occurred ≥ 3 years before the first clinical manifestation, 1 occurred ≥ 1 years before, and 1 occurred after the first manifestation. Of all pregnancies, 12 were pregnancy losses: 5 were classified as miscarriages and 3 as stillbirths. Of all pregnancy losses, 10 occurred ≥ 3 years before the diagnosis, 1 occurred after the first manifestation. All pregnancy losses occurred in 8 patients.

CONCLUSIONS

Close to half of the patients with previous pregnancies reported at least one pregnancy loss, most of these occurred ≥ 3 years before the diagnosis. This percentage is higher than expected for their age group in our country.

Complement regulator CD59 prevents peripheral organ injury in rats made seropositive for neuromyelitis optica immunoglobulin G

Pathogenesis in aquaporin-4 immunoglobulin G (AQP4-IgG) seropositive neuromyelitis optica spectrum disorders (herein called NMO) involves complement-dependent cytotoxicity initiated by AQP4-IgG binding to astrocyte AQP4. We recently reported that rats lacking complement inhibitor protein CD59 were highly susceptible to development of NMO pathology in brain and spinal cord following direct AQP4-IgG administration (Yao and Verkman, Acta Neuropath Commun 2017, 5:15). Here, we report evidence that CD59 is responsible for protection of peripheral, AQP4-expressing tissues in seropositive NMO. Rats made seropositive by intraperitoneal injection of AQP4-IgG developed marked weakness by 24 h and died soon thereafter. Serum creatine phosphokinase at 24 h was >900-fold greater in seropositive CD59^-/- rats than in seropositive CD59^+/+ (or control) rats. AQP4-expressing cells in skeletal muscle and kidney, but not in stomach, of seropositive CD59^-/- rats showed injury with deposition of AQP4-IgG and activated complement C5b-9, and inflammation. Organ injury in seropositive CD59^-/- rats was prevented by a complement inhibitor. Significant pathological changes in seropositive CD59^-/- rats were not seen in optic nerve, spinal cord or brain, including circumventricular tissue. These results implicate a major protective role of CD59 outside of the central nervous system in seropositive NMO, and hence offer an explanation as to why peripheral, AQP4-expressing cells are largely unaffected in NMO.

The Role of Peripheral CNS-Directed Antibodies in Promoting Inflammatory CNS Demyelination

In central nervous system (CNS) demyelinating disorders, such as multiple sclerosis (MS), neuromyelitis optica (NMO) and related NMO-spectrum disorders (NMO-SD), a pathogenic role for antibodies is primarily projected into enhancing ongoing CNS inflammation by directly binding to target antigens within the CNS. This scenario is supported at least in part, by antibodies in conjunction with complement activation in the majority of MS lesions and by deposition of anti-aquaporin-4 (AQP-4) antibodies in areas of astrocyte loss in patients with classical NMO. A currently emerging subgroup of AQP-4 negative NMO-SD patients expresses antibodies against myelin oligodendrocyte glycoprotein (MOG), again suggestive of their direct binding to CNS myelin. However, both known entities of anti-CNS antibodies, anti-AQP-4- as well as anti-MOG antibodies, are predominantly found in the serum, which raises the questions why and how a humoral response against CNS antigens is raised in the periphery, and in a related manner, what pathogenic role these antibodies may exert outside the CNS. In this regard, recent experimental and clinical evidence suggests that peripheral CNS-specific antibodies may indirectly activate peripheral CNS-autoreactive T cells by opsonization of otherwise unrecognized traces of CNS antigen in peripheral compartments, presumably drained from the CNS by its newly recognized lymphatic system. In this review, we will summarize all currently available data on both possible roles of antibodies in CNS demyelinating disorders, first, directly enhancing damage within the CNS, and second, promoting a peripheral immune response against the CNS. By elaborating on the latter scenario, we will develop the hypothesis that peripheral CNS-recognizing antibodies may have a powerful role in initiating acute flares of CNS demyelinating disease and that these humoral responses may represent a therapeutic target in its own right.

Expanding Role of T Cells in Human Autoimmune Diseases of the Central Nervous System

It is being increasingly recognized that a dysregulation of the immune system plays a vital role in neurological disorders and shapes the treatment of the disease. Aberrant T cell responses, in particular, are key in driving autoimmunity and have been traditionally associated with multiple sclerosis. Yet, it is evident that there are other neurological diseases in which autoreactive T cells have an active role in pathogenesis. In this review, we report on the recent progress in profiling and assessing the functionality of autoreactive T cells in central nervous system (CNS) autoimmune disorders that are currently postulated to be primarily T cell driven. We also explore the autoreactive T cell response in a recently emerging group of syndromes characterized by autoantibodies against neuronal cell-surface proteins. Common methodology implemented in T cell biology is further considered as it is an important determinant in their detection and characterization. An improved understanding of the contribution of autoreactive T cells expands our knowledge of the autoimmune response in CNS disorders and can offer novel methods of therapeutic intervention.

Enhancing Brain Lesions during Acute Optic Neuritis and/or Longitudinally Extensive Transverse Myelitis May Portend a Higher Relapse Rate in Neuromyelitis Optica Spectrum Disorders

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorders are inflammatory demyelinating disorders with optic neuritis and/or longitudinally extensive transverse myelitis episodes. We now know that neuromyelitis optica spectrum disorders are associated with antibodies to aquaporin-4, which are highly concentrated on astrocytic end-feet at the blood-brain barrier. Immune-mediated disruption of the blood-brain barrier may manifest as contrast enhancement on brain MR imaging. We aimed to delineate the extent and frequency of contrast enhancement on brain MR imaging within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and to correlate contrast enhancement with outcome measures.

MATERIALS AND METHODS

Brain MRIs of patients with neuromyelitis optica spectrum disorders were evaluated for patterns of contrast enhancement (periependymal, cloudlike, leptomeningeal, and so forth). The Fisher exact test was used to evaluate differences between the proportion of contrast enhancement in patients who were seropositive and seronegative for aquaporin-4 antibodies. The Mann-Whitney test was used to compare the annualized relapse rate and disease duration between patients with and without contrast enhancement and with and without seropositivity.

RESULTS

Brain MRIs of 77 patients were evaluated; 59 patients (10 males, 49 females) were scanned within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and were included in the analysis. Forty-eight patients were seropositive, 9 were seronegative, and 2 were not tested for aquaporin-4 antibodies. Having brain contrast enhancement of any type during an acute attack was significantly associated with higher annualized relapse rates (P = .03) and marginally associated with shorter disease duration (P = .05). Having periependymal contrast enhancement was significantly associated with higher annualized relapse rates (P = .03).

CONCLUSIONS

Brain MRIs of patients with neuromyelitis optica spectrum disorders with contrast enhancement during an acute relapse of optic neuritis and/or longitudinally extensive transverse myelitis are associated with increased annual relapse rates.

Different Phenotypes at Onset in Neuromyelitis Optica Spectrum Disorder Patients with Aquaporin-4 Autoimmunity

Background

Although rare, brain abnormalities without optic neuritis (ON) or transverse myelitis (TM) diagnosed with neuromyelitis optica spectrum disorder (NMOSD) have been reported in patients positive for the aquaporin-4 (AQP4) antibody.

Objective

To analyze demographic and clinical differences among NMOSD patients without ON or TM, those with either ON or TM, and patients with simultaneous ON and TM at disease onset.

Methods

In this retrospective study, patients who were positive for the AQP4 antibody, as detected using a cell-based assay, at the Second Affiliated Hospital of Guangzhou Medical University in China were recruited. Demographic and clinical data were obtained from each patient’s medical record.

Results

A total of 292 patients were included in this study and were divided into four subgroups based on their initial manifestations: (i) NMOSD without ON or TM (NMOSD-ON⁻TM⁻, n = 70); (ii) NMOSD with ON (NMOSD-ON⁺, n = 95); (iii) NMOSD with TM (NMOSD-TM⁺, n = 116); and (iv) simultaneous ON and TM [neuromyelitis optica (NMO), n = 11]. We found that age at onset was lower in the NMOSD-ON⁻TM⁻ group than that in the other groups. The interval from the first episode to relapse was shorter in the NMOSD-ON⁻TM⁻ group than that in NMOSD-TM⁺ group. Cerebral spinal fluid white cell counts and protein levels were significantly higher in the NMOSD-ON⁻TM⁻ group than those in the other groups. Lower Expanded Disability Status Scale scores were observed in the NMOSD-ON⁻TM⁻ group. Brain abnormalities, including in area postrema and hemisphere lesions, were more frequent in the NMOSD-ON⁻TM⁻ group. Kaplan–Meier analysis showed that patients in the NMOSD-ON⁻TM⁻ group experienced earlier relapse than those in other groups. Conversion to NMO in the NMOSD-ON⁺ group was greater than that in the other groups. Only 14 patients (4.8%, 14/292) had pure brain abnormalities, of which 12 had disease duration of several more years and 8 (57.1%) experienced relapses.

Conclusion

NMOSD patients with different initial manifestations present with significant differences in clinical features during follow-up. Patients with long-term AQP4 autoimmunity in the brain in the absence of ON or TM are not common.

MOG antibody-positive, benign, unilateral, cerebral cortical encephalitis with epilepsy

Objective:

To describe the features of adult patients with benign, unilateral cerebral cortical encephalitis positive for the myelin oligodendrocyte glycoprotein (MOG) antibody.

Methods:

In this retrospective, cross-sectional study, after we encountered an index case of MOG antibody–positive unilateral cortical encephalitis with epileptic seizure, we tested for MOG antibody using our in-house, cell-based assay in a cohort of 24 consecutive adult patients with steroid-responsive encephalitis of unknown etiology seen at Tohoku University Hospital (2008–2014). We then analyzed the findings in MOG antibody–positive cases.

Results:

Three more patients, as well as the index case, were MOG antibody–positive, and all were adult men (median age 37 years, range 23–39 years). The main symptom was generalized epileptic seizure with or without abnormal behavior or consciousness disturbance. Two patients also developed unilateral benign optic neuritis (before or after seizure). In all patients, brain MRI demonstrated unilateral cerebral cortical fluid-attenuated inversion recovery hyperintense lesions, which were swollen and corresponded to hyperperfusion on SPECT. CSF studies showed moderate mononuclear pleocytosis with some polymorphonuclear cells and mildly elevated total protein levels, but myelin basic protein was not elevated. A screening of encephalitis-associated autoantibodies, including aquaporin-4, glutamate receptor, and voltage-gated potassium channel antibodies, was negative. All patients received antiepilepsy drugs and fully recovered after high-dose methylprednisolone, and the unilateral cortical MRI lesions subsequently disappeared. No patient experienced relapse.

Conclusions:

These MOG antibody–positive cases represent unique benign unilateral cortical encephalitis with epileptic seizure. The pathology may be autoimmune, although the findings differ from MOG antibody–associated demyelination and Rasmussen and other known immune-mediated encephalitides.

Aquaporin-4 antibody titration in NMO patients treated with rituximab: A retrospective study

Objective:

We undertook an observational retrospective study to investigate the usefulness of aquaporin-4 (AQP4) antibodies (Ab) titration in the management of patients with neuromyelitis optica (NMO) treated with rituximab (RTX) by studying (1) the correlation between AQP4-Ab titer and disease activity, (2) the influence of RTX on antibody levels, and (3) the association between AQP4-Ab levels and responsiveness to RTX.

Methods:

A cell-based assay was used for AQP4-Ab titration in 322 serum samples from 7 patients with NMO treated with RTX (median follow-up 65 months), according to a treatment-to-target approach. Serum samples were collected every month following standardized procedures.

Results:

(1) In group analysis, AQP4-Ab titers correlated with the disease activity, showing higher titers during and preceding relapses than during remission. However, in individual analysis, an increase in AQP4-Ab titers and CD19+ B cells did not always precede a relapse. (2) A reduction of AQP4-Ab titers in the short-term and long-term period was observed during RTX treatment. (3) Reduction of AQP4-Ab titers was observed in responder patients both 3 months after RTX infusion and in the long-term follow-up. In one nonresponder patient, AQP4-Ab levels never decreased during the treatment period.

Conclusions:

Titration of AQP4-Abs could be useful in the clinical management of patients with NMO treated with RTX: titration before each reinfusion and 3 months after each reinfusion may provide information about responsiveness to RTX. Although a relationship among AQP4-Ab levels, disease activity, and response to RTX was observed, the usefulness of AQP4-Ab titration to predict relapses is limited.