Single-cell analysis of anti-BCMA CAR T cell therapy in patients with central nervous system autoimmunity.

Chimeric antigen receptor (CAR) T cell immunotherapy for the treatment of neurological autoimmune diseases is promising, but CAR T cell kinetics and immune alterations after treatment are poorly understood. Here, we performed single-cell multi-omics sequencing of paired cerebrospinal fluid (CSF) and blood samples from patients with neuromyelitis optica spectrum disorder (NMOSD) treated with anti-B cell maturation antigen (BCMA) CAR T cells. Proliferating cytotoxic-like CD8+ CAR T cell clones were identified as the main effectors in autoimmunity. Anti-BCMA CAR T cells with enhanced features of chemotaxis efficiently crossed the blood-CSF barrier, eliminated plasmablasts and plasma cells in the CSF, and suppressed neuroinflammation. The CD44-expressing early memory phenotype in infusion products was potentially associated with CAR T cell persistence in autoimmunity. Moreover, CAR T cells from patients with NMOSD displayed distinctive features of suppressed cytotoxicity compared with those from hematological malignancies. Thus, we provide mechanistic insights into CAR T cell function in patients with neurological autoimmune disease.

Radiologic Lag and Brain MRI Lesion Dynamics During Attacks in MOG Antibody-Associated Disease.

BACKGROUND AND OBJECTIVES: Knowledge of the evolution of CNS demyelinating lesions within attacks could assist diagnosis. We evaluated intra-attack lesion dynamics in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) vs multiple sclerosis (MS) and aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (AQP4+NMOSD). METHODS: This retrospective observational multicenter study included consecutive patients from Mayo Clinic (USA) and Great Ormond Street Hospital for Children (UK). Inclusion criteria were as follows: (1) MOGAD, MS, or AQP4+NMOSD diagnosis; (2) availability of ≥2 brain MRIs (within 30 days of attack onset); and (3) brain involvement (i.e., ≥1 T2 lesion) on ≥1 brain MRI. The initial and subsequent brain MRIs within a single attack were evaluated for the following: new T2 lesions(s); resolved T2 lesion(s); both; or no change. This was compared between MOGAD, MS, and AQP4+NMOSD attacks. We used the Mann-Whitney U test and χ2/Fisher exact test for statistical analysis. RESULTS: Our cohort included 55 patients with MOGAD (median age, 14 years; interquartile range [IQR] 5-34; female sex, 29 [53%]) for a total of 58 attacks. The comparison groups included 38 patients with MS, and 19 with AQP4+NMOSD. In MOGAD, the initial brain MRI (median of 5 days from onset [IQR 3-9]) was normal in 6/58 (10%) attacks despite cerebral symptoms (i.e., radiologic lag). The commonest reason for repeat MRI was clinical worsening or no improvement (33/56 [59%] attacks with details available). When compared with the first MRI, the second intra-attack MRI (median of 8 days from initial scan [IQR 5-13]) showed the following: new T2 lesion(s) 27/58 (47%); stability 24/58 (41%); resolution of T2 lesion(s) 4/58 (7%); or both new and resolved T2 lesions 3/58 (5%). Findings were similar between children and adults. Steroid treatment was associated with resolution of ≥1 T2 lesion (6/28 [21%] vs 1/30 [3%], p = 0.048) and reduced the likelihood of new T2 lesions (9/28 vs 18/30, p = 0.03). Intra-attack MRI changes favored MOGAD (34/58 [59%]) over MS (10/38 [26%], p = 0.002) and AQP4+NMOSD (4/19 [21%], p = 0.007). Resolution of ≥1 T2 lesions was exclusive to MOGAD (7/58 [12%]). DISCUSSION: Radiologic lag is common within MOGAD attacks. Dynamic imaging with frequent appearance and occasional disappearance of lesions within a single attack suggest MOGAD diagnosis over MS and AQP4+NMOSD. These findings have implications for clinical practice, clinical trial attack adjudication, and understanding of MOGAD pathogenesis.

Optic chiasm involvement in multiple sclerosis, aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein-associated disease.

BACKGROUND: Optic neuritis (ON) is a common feature of inflammatory demyelinating diseases (IDDs) such as multiple sclerosis (MS), aquaporin 4-antibody neuromyelitis optica spectrum disorder (AQP4 + NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, the involvement of the optic chiasm (OC) in IDD has not been fully investigated. AIMS: To examine OC differences in non-acute IDD patients with (ON+) and without ON (ON-) using magnetisation transfer ratio (MTR), to compare differences between MS, AQP4 + NMOSD and MOGAD and understand their associations with other neuro-ophthalmological markers. METHODS: Twenty-eight relapsing-remitting multiple sclerosis (RRMS), 24 AQP4 + NMOSD, 28 MOGAD patients and 32 healthy controls (HCs) underwent clinical evaluation, MRI and optical coherence tomography (OCT) scan. Multivariable linear regression models were applied. RESULTS: ON + IDD patients showed lower OC MTR than HCs (28.87 ± 4.58 vs 31.65 ± 4.93; p = 0.004). When compared with HCs, lower OC MTR was found in ON + AQP4 + NMOSD (28.55 ± 4.18 vs 31.65 ± 4.93; p = 0.020) and MOGAD (28.73 ± 4.99 vs 31.65 ± 4.93; p = 0.007) and in ON- AQP4 + NMOSD (28.37 ± 7.27 vs 31.65 ± 4.93; p = 0.035). ON+ RRMS had lower MTR than ON- RRMS (28.87 ± 4.58 vs 30.99 ± 4.76; p = 0.038). Lower OC MTR was associated with higher number of ON (regression coefficient (RC) = -1.15, 95% confidence interval (CI) = -1.819 to -0.490, p = 0.001), worse visual acuity (RC = -0.026, 95% CI = -0.041 to -0.011, p = 0.001) and lower peripapillary retinal nerve fibre layer (pRNFL) thickness (RC = 1.129, 95% CI = 0.199 to 2.059, p = 0.018) when considering the whole IDD group. CONCLUSION: OC microstructural damage indicates prior ON in IDD and is linked to reduced vision and thinner pRNFL.

Stage-dependent immunity orchestrates AQP4 antibody-guided NMOSD pathology: a role for netting neutrophils with resident memory T cells in situ.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood-brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive 'stage-dependent' investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under "standby" conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.

[Anti-MOG associated disease]. / Maladie du spectre des anticorps anti-MOG.

Myelin Oligodendrocyte Glycoprotein Antibody Associated Disease (MOGAD) is an autoimmune disease responsible for demyelination of the central nervous system that can occur in adults or children. Overlapping phenotypes between MOGAD, multiple sclerosis (MS) and neuromyelitis optica spectrum disease (NMOSD) have been described. The diagnostic criteria for MOGAD were proposed by a panel of international experts and published in 2023. Defining clinical, biological and imaging characteristics specific to this entity helps to improve diagnostic specificity. In this article, we present the clinical characteristics suggestive of MOGAD and discuss the importance of the antibody detection method and therapeutic management.

La maladie du spectre des anticorps anti-MOG (glycoprotéine de myéline oligodendrocytaire) (myelin oligodendrocyte glycoprotein antibody-associated disease, MOGAD) est une maladie autoimmune responsable d'une démyélinisation du système nerveux central pouvant survenir chez les adultes ou les enfants. Des phénotypes de chevauchement entre MOGAD, sclérose en plaques et maladie du spectre de la neuromyélite optique ont été décrits. Les critères diagnostiques de MOGAD ont été proposés par un panel d'experts internationaux et publiés en 2023. Ils permettent de définir des caractéristiques cliniques, biologiques et d'imagerie propres à cette entité, afin d'améliorer la spécificité diagnostique. Nous présentons dans cet article les caractéristiques cliniques en faveur de MOGAD, discutons de l'importance de la méthode de détection des anticorps et terminons par une mise au point sur la prise en charge thérapeutique.

Cognitive and psychopathological features of neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease: A narrative review.

Clinicians are becoming increasingly aware of the cognitive and psychopathological consequences of neurological diseases, which were once thought to manifest with motor and sensory impairments only. The cognitive profile of multiple sclerosis, in particular, is now well-characterised. Similar efforts are being made to better characterise the cognitive profile of other central nervous system inflammatory demyelinating autoimmune disorders. This review discusses the current understanding of the cognitive and psychological features of neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Detailed analysis of the cognitive sequelae of the above conditions can not only assist with understanding disease pathogenesis but also can guide appropriate management of the symptoms and consequently, improve the quality of life and long-term outcomes for these patients. This narrative review will also identify research gaps and provide recommendations for future directions in the field.

Rituximab-induced gut microbiota changes in Chinese neuromyelitis optica spectrum disorders.

BACKGROUND: Recent evidence shows that immunosuppressive agents can affect the gut microbiota in autoimmune diseases. However, the relationship between the gut microbiome and B-cell depletion immunotherapy in neuromyelitis optica spectrum disorder (NMOSD) remains poorly understood. OBJECTIVES: To evaluate the distinct intestinal microbial patterns and serum cytokine levels after short-term rituximab treatment (three months) in patients with NMOSD. METHODS: Firstly, we conducted a cross-sectional study involving 46 treatment-naïve NMOSD patients and 48 matched healthy controls. We collected fecal specimens, which were then analyzed using next-generation sequencing, and quantified serum cytokines. Subsequently, fecal and serum samples were re-collected and re-evaluated in 31 of the 46 treatment-naïve NMOSD patients after RTX treatment. RESULTS: Comparing the gut microbiome of treatment-naïve NMOSD patients to that of healthy controls revealed low α-diversity and distinct microbial compositions in the former. The microbial composition in NMOSD patients underwent changes following three months of RTX treatment. Specifically, the levels of IL-17F and IL-6 decreased, while those of IL-10 and TNFα increased after RTX treatment. LEfSe analysis identified 27 KEGG categories with significantly differential abundances between NMOSD patients and RTX treatment group. CONCLUSIONS: Our study provides a comprehensive understanding of the gut microbiota landscape in the context of B-cell depletion immunotherapy. We observed dysbiosis in the gut microbiome of NMOSD patients, which was partially alleviated by three months of RTX treatment. This suggests that B-cell depletion may play a crucial role in driving changes in the gastrointestinal environment.

Cerebrospinal fluid eosinophils in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease.

BACKGROUND: Eosinophils in cerebrospinal fluid (CSF) are an uncommon finding most often associated with parasitic infections, but have also been described in some neuroinflammatory disorders. Eosinophilic infiltration is not thought to be a typical feature of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). We aim to describe the rate of CSF eosinophil positivity in a cohort of pediatric MOGAD patients. METHODS: Single-center retrospective chart review of pediatric MOGAD patients. Clinical and laboratory data was collected from the electronic medical record and analyzed. RESULTS: Of 46 pediatric patients with positive serum myelin oligodendrocyte glycoprotein antibody (MOG-IgG) identified, 38 patients fulfilling internationally proposed MOGAD diagnostic criteria were included for analysis. 6 patients with MOGAD were excluded as no CSF data was available, and 2 patients with positive MOG-IgG but diagnosis more consistent with MS were excluded. Median age was 7.3 years, and 19/38 (50 %) were female. Acute disseminated encephalomyelitis (ADEM) was the most common presenting phenotype (23/38, 61 %), and other phenotypes included optic neuritis (10/38, 26 %), transverse myelitis (3/38, 8 %), and neuromyelitis optica spectrum disorder (NMOSD) (2/38, 5 %). 12 of 36 (33 %) patients with all lumbar puncture (LP) data available had CSF eosinophils present, with eosinophil mean of 3 % and range from 1 % to 18 % of CSF while blood cells. CONCLUSION: CSF eosinophils were present in one third of pediatric MOGAD patients, which is a higher rate than previously reported in either MOGAD or aquaporin-4 antibody positive NMOSD cohorts. Understanding the CSF composition of pediatric MOGAD patients helps to facilitate more prompt diagnosis and treatment and may shed light onto underlying pathologic mechanisms of disease with the goal to inform future therapeutic targets.

Role of C5 inhibitors in neuromyelitis optica spectrum disorders with seropositive anti-aquaporin-4 antibody: A systematic review and meta-analysis.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder characterized by relapses of inflammation and demyelination primarily affecting the optic nerve and the spinal cord. C5 complement inhibition is an effective therapeutic approach in the treatment of NMOSD. In this systematic review and meta-analysis, we aimed to determine the role of C5 inhibitors in the treatment of patients with seropositive anti-aquaporin-4 antibody (AQP4+IgG) NMOSD. METHODS: This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Relevant articles were systematically searched through Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases until October 6th, 2023. We included randomized clinical trials (RCTs) that investigated the treatment with C5 inhibitors compared to placebo in patients with seropositive NMOSD. The primary endpoint was the rates of first adjudicated relapse. Secondary endpoints included different disability and quality of life measures. The random-effects model was used for all statistical analyses. RESULTS: Two RCTs with a total of 201 patients were included. C5 inhibitors demonstrated significant reduction of first adjudicated relapse (risk ratio (RR) = 0.05, 95 % CI 0.01-0.15) and Hauser Ambulation Index (HAI) (mean difference (MD): -0.79, 95 % CI -1.27 to -0.31). There was no significant difference between the two groups in Expanded Disability Status Scale (EDSS) (MD -0.23, 95 % CI -0.54-0.08). C5 inhibitors significantly improved the mean change in EQ-5D index (MD 0.08, 95 % CI 0.01-0.14; P = 0.02); however, no significant difference was shown in the mean change in EQ-5D VAS (MD 3.79, 95 % CI -1.61 to 9.19; P = 0.17). Safety measures were comparable between C5 inhibitors and placebo. CONCLUSION: NMOSD Patients with AQP4+IgG receiving C5 inhibitors have lower rate of relapses and improved levels of disability and quality of life. Real-world studies are warranted to establish the long-term safety of C5 inhibitors.

Seizures in inflammatory demyelinating disorders of the central nervous system.

BACKGROUND: Multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may be associated with acute symptomatic seizures and chronic epilepsy as well. The clinical features of the seizures and/or accompanying epilepsy seen in each disease group may vary. In this study, we aimed to contribute to the existing literature by describing the clinical features of seizures and epilepsy in our demyelinating patient population. METHODS: We retrospectively analyzed patients who were followed up in our tertiary referral center neurology demyelinating diseases outpatient clinic between 2019 and 2024. Patients who had at least one seizure before, simultaneously, or after the diagnosis of demyelinating disease were included in the study. RESULTS: Among 1735 patients with MS, 40 had experienced at least one epileptic seizure (2.3 %). Thirty patients (1.7 %) had seizures that could not be explained by another factor than MS. When secondary progressive MS (SPMS) and relapsing-remitting MS (RRMS) were compared, the interval between MS-epilepsy diagnosis was longer and seizure recurrence was more in SPMS. However, the prognosis of epilepsy was good in both subtypes. There were 21 patients followed up with antibody-positive neuromyelitis optica spectrum disorder. No patient had a seizure during the follow-up. We identified 56 patients who fulfilled the criteria for MOGAD with high antibody titers. Seizures were observed in three of them (5.4 %). All of them had status epilepticus either at the onset or during the course of the disease. CONCLUSION: Even rare, seizures constitute one of the important clinical features of the inflammatory demyelinating disorders of the central nervous system. The pathophysiologic mechanism underlying seizures in MS is still not clear. Seizures may occur through different mechanisms in patients where seizures are the initial symptom or a sign of relapse and those that occur spontaneously during the progressive course of the disease. Prevalence of status epilepticus was common in MOGAD patients. Given the rarity of the seizures in CNS demyelinating disorders, it is difficult the define clinical and pathophysiological characteristics of accompanying seizures and epilepsy. Future studies conducted on large patient groups will contribute to the existing literature.

Epidemiology of aquaporin-4-IgG-positive NMOSD in Sardinia.

PURPOSE: The Italian Island of Sardinia (population, 1,578,146) is recognized for the high risk of multiple sclerosis (MS) but the epidemiological burden of other less common demyelinating diseases of the central nervous system (CNS), such as aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD), is unknown. In this study, we determined the incidence and prevalence of AQP4-IgG+NMOSD in Sardinia over a ten-year study period (2013-2022). METHODS: Patients with a diagnosis of AQP4-IgG+NMOSD (per 2015 IPND diagnostic criteria) were retrospectively identified using two sources: (1) Archives of the reference and only laboratory for AQP4-IgG testing in Sardinia; and (2) medical records of the four MS units in the island. Incidence (January 2013-December 2022) and prevalence (December 31, 2022) were calculated. RESULTS: A total of 45 cases were included: incident, 31; prevalent, 41. The median age (range) at disease presentation was 51 (6-78) years; female/male ratio was 9:1. The crude (95 % CI) incidence and prevalence were 1.9 (1.3-2.7) per million and 2.6 (1.9-3.5) per 100,000, respectively. Prevalence increased from 2013 (1.1 per 100,000) to 2022 (2.6 per 100,000); p = 0.002. After age-standardization to the world, incidence and prevalence (95 % CI) decreased to 1.3 (0.7-2) per million and 1.8 (1.3-2.3) per 100,000, respectively. Coexisting immune-mediated disorders, mostly autoimmune thyroiditis, were reported in 50 % of patients. CONCLUSIONS: The epidemiology of AQP4-IgG+NMOSD in Sardinia is overall in line with other Caucasian populations. The high MS risk in the island seems disease-specific and not associated with an increased risk of other CNS demyelinating disorders, confirming different pathophysiology.

A study of referral bias in NMOSD and MOGAD cohorts.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are rare disorders often seen in highly specialized services or tertiary centres. We aimed to assess if cohort characteristics depend on the origin of the referral catchment areas serviced by our centre (i.e. local, regional or national). METHODS: Retrospective cohort study using a national referral service database including local (Oxfordshire), regional (Oxfordshire and neighbouring counties), and national patients. We included patients with the diagnosis of NMOSD, seronegative NMOSD or MOGAD, followed at the Oxford Neuromyelitis Optica Service. RESULTS: We included 720 patients (331 with MOGAD, 333 with aquaporin-4 antibody (AQP4)-NMOSD, and 56 with seronegative NMOSD. The distribution of diagnoses was similar across referral cohorts. There were no significant differences in the proportion of pediatric onset patients, sex, or onset phenotype; more White AQP4-NMOSD patients were present in the local than in the national cohort (81 % vs 52 %). Despite no differences in follow-up time, more relapsing MOGAD disease was present in the national than in the local cohort (42.9 % vs. 24 %, p = 0.029). CONCLUSION: This is the first study assessing the impact of potential referral bias in cohorts of NMOSD or MOGAD. The racial difference in the AQP4-NMOSD cohorts likely reflects the variation in the population demographics rather than a referral bias. The over representation of relapsing MOGAD patients in the national cohort probably is a true referral bias and highlights the need to analyze incident cohorts when describing disease course and prognosis. It seems reasonable therefore to compare MOGAD and NMOSD patients seen withing specialised centres to general neurology services, provided both use similar antibody assays.

Brain and spinal cord atrophy in NMOSD and MOGAD: Current evidence and future perspectives.

Neuromyelitis optica spectrum disorder (NMOSD) is a severe form of inflammation of the central nervous system (CNS) including acute myelitis, optic neuritis and brain syndrome. Currently, the classification of NMOSD relies on serologic testing, distinguishing between seropositive or seronegative anti-aquaporin-4 antibody (AQP4) status. However, the situation has recently grown more intricate with the identification of patients exhibiting the NMOSD phenotype and myelin oligodendrocyte glycoprotein antibodies (MOGAD). NMOSD is primarily recognized as a relapsing disorder; MOGAD can manifest with either a monophasic or relapsing course. Significant symptomatic inflammatory CNS injuries with stability in clinical findings outside the acute phase are reported in both diseases. Nevertheless, recent studies have proposed the existence of a subclinical pathological process, revealing longitudinal changes in brain and spinal cord atrophy. Within this context, we summarise key studies investigating brain and spinal cord measurements in adult NMOSD and MOGAD. We also explore their relationship with clinical aspects, highlight differences from multiple sclerosis (MS), and address future challenges. This exploration is crucial for determining the presence of chronic damage processes, enabling the customization of therapeutic interventions irrespective of the acute phase of the disease.

Increased levels of circulating soluble CD226 in multiple sclerosis.

BACKGROUND: The glycoprotein CD226 plays a key role in regulating immune cell function. Soluble CD226 (sCD226) is increased in sera of patients with several chronic inflammatory diseases but its levels in neuroinflammatory diseases such as multiple sclerosis (MS) are unknown. OBJECTIVE: To investigate the presence and functional implications of sCD226 in persons with multiple sclerosis (pwMS) and other neurological diseases. METHODS: The mechanisms of sCD226 production were first investigated by analyzing CD226 surface expression levels and supernatants of CD3/CD226-coactivated T cells. The role of sCD226 on dendritic cell maturation was evaluated. The concentration of sCD226 in the sera from healthy donors (HD), pwMS, neuromyelitis optica (NMO), and Alzheimer's disease (AD) was measured. RESULTS: CD3/CD226-costimulation induced CD226 shedding. Addition of sCD226 to dendritic cells during their maturation led to an increased production of the pro-inflammatory cytokine interleukin (IL)-23. We observed a significant increase in sCD226 in sera from pwMS and NMO compared to HD and AD. In MS, levels were increased in both relapsing-remitting multiple sclerosis (RRMS) and secondary-progressive multiple sclerosis (SPMS) compared to clinically isolated syndrome (CIS). CONCLUSION: Our data suggest that T-cell activation leads to release of sCD226 that could promote inflammation and raises the possibility of using sCD226 as a biomarker for neuroinflammation.

B cells orchestrate tolerance to the neuromyelitis optica autoantigen AQP4.

Neuromyelitis optica is a paradigmatic autoimmune disease of the central nervous system, in which the water-channel protein AQP4 is the target antigen1. The immunopathology in neuromyelitis optica is largely driven by autoantibodies to AQP42. However, the T cell response that is required for the generation of these anti-AQP4 antibodies is not well understood. Here we show that B cells endogenously express AQP4 in response to activation with anti-CD40 and IL-21 and are able to present their endogenous AQP4 to T cells with an AQP4-specific T cell receptor (TCR). A population of thymic B cells emulates a CD40-stimulated B cell transcriptome, including AQP4 (in mice and humans), and efficiently purges the thymic TCR repertoire of AQP4-reactive clones. Genetic ablation of Aqp4 in B cells rescues AQP4-specific TCRs despite sufficient expression of AQP4 in medullary thymic epithelial cells, and B-cell-conditional AQP4-deficient mice are fully competent to raise AQP4-specific antibodies in productive germinal-centre responses. Thus, the negative selection of AQP4-specific thymocytes is dependent on the expression and presentation of AQP4 by thymic B cells. As AQP4 is expressed in B cells in a CD40-dependent (but not AIRE-dependent) manner, we propose that thymic B cells might tolerize against a group of germinal-centre-associated antigens, including disease-relevant autoantigens such as AQP4.

The landscape of PBMCs in AQP4-IgG seropositive NMOSD and MOGAD, assessed by high dimensional mass cytometry.

OBJECTIVES: Data on peripheral blood mononuclear cells (PBMCs) characteristics of aquaporin-4 (AQP4)-IgG seropositive neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are lacking. In this study, we describe the whole PBMCs landscape of the above diseases using cytometry by time-of-flight mass spectrometry (CyTOF). METHODS: The immune cell populations were phenotyped and clustered using CyTOF isolated from 27 AQP4-IgG seropositive NMOSD, 11 MOGAD patients, and 15 healthy individuals. RNA sequencing was employed to identify critical genes. Fluorescence cytometry and qPCR analysis were applied to further validate the algorithm-based results that were obtained. RESULTS: We identified an increased population of CD11b+ mononuclear phagocytes (MNPs) in patients with high expression of CCR2, whose abundance may correlate with brain inflammatory infiltration. Using fluorescence cytometry, we confirmed the CCR2+ monocyte subsets in a second cohort of patients. Moreover, there was a wavering of B, CD4+ T, and NKT cells between AQP4-IgG seropositive NMOSD and MOGAD. CONCLUSIONS: Our findings describe the whole landscape of PBMCs in two similar demyelinated diseases and suggest that, besides MNPs, T, NK and B, cells were all involved in the pathogenesis. The identified cell population may be used as a predictor for monitoring disease development or treatment responses.

Complement biomarkers reflect the pathological status of neuromyelitis optica spectrum disorders.

Complement is involved in the pathogenesis of neuroimmune disease, but the detailed pathological roles of the complement pathway remain incompletely understood. Recently, eculizumab, a humanized anti-C5 monoclonal antibody, has been clinically applied against neuroimmune diseases such as myasthenia gravis and neuromyelitis optica spectrum disorders (NMOSD). Clinical application of eculizumab is also being investigated for another neuroimmune disease, Guillain-Barré syndrome (GBS). However, while the effectiveness of eculizumab for NMOSD is extremely high in many cases, there are some cases of myasthenia gravis and GBS in which eculizumab has little or no efficacy. Development of effective biomarkers that reflect complement activation in these diseases is therefore important. To identify biomarkers that could predict disease status, we retrospectively analyzed serum levels of complement factors in 21 patients with NMOSD and 25 patients with GBS. Ba, an activation marker of the alternative complement pathway, was elevated in the acute phases of both NMOSD and GBS. Meanwhile, sC5b-9, an activation marker generated by the terminal complement pathway, was elevated in NMOSD but not in GBS. Complement factor H (CFH), a complement regulatory factor, was decreased in the acute phase as well as in the remission phase of NMOSD, but not in any phases of GBS. Together, these findings suggest that complement biomarkers, such as Ba, sC5b-9 and CFH in peripheral blood, have potential utility in understanding the pathological status of NMOSD.

Analysis of LAP+ and GARP+ Treg subsets in peripheral blood of patients with neuromyelitis optica spectrum disorders.

INTRODUCTION: Neuromyelitis optica spectrum disorder (NMOSD) is a group of antibody-mediated inflammatory demyelinating central nervous system diseases. T lymphocytes participate in NMOSD pathogenesis, with regulatory T cells (Treg) being the core in maintaining immune homeostasis. Studies have revealed that different Treg subsets play different roles in autoimmune diseases. The distribution of LAP+ or GARP+ Treg subsets in NMOSD may help us deeply understand their immune mechanism. METHODS: This study reviewed 22 NMOSD patients and 20 normal controls. Flow cytometric analysis was utilized to detect subsets of Treg cells expressing Foxp3, Helios, LAP, or GARP in peripheral blood. ELISA was used to detect plasma TGF-ß1 and IL-10. In addition, changes in the proportion of Treg cell subsets before and after glucocorticoid treatment in 10 patients were analyzed. RESULTS: Compared with healthy controls, LAP and GARP expressions were significantly downregulated in the peripheral blood of NMOSD patients. TGF-ß1 expression in NMOSD patients was lower and was positively correlated with the ratio of CD4+GARP+ Treg cells. After treatment with glucocorticoid, LAP and GARP expressions in the peripheral blood of NMOSD patients were upregulated. CONCLUSIONS: The proportion of Treg cells expressing LAP and GARP is downregulated, implying that Treg cells with the best inhibitory function are insufficient to maintain autoimmune homeostasis in NMOSD patients. Upregulation of Treg cells expressing LAP and GARP in NMOSD patients may be one of the mechanisms of glucocorticoid treatment.

Estimated prevalence of AQP4 positive neuromyelitis optica spectrum disorder and MOG antibody associated disease in São Paulo, Brazil.

BACKGROUND: Numerous studies addressed the prevalence of multiple sclerosis, but prevalence studies of NMOSD and, particularly, MOGAD are scarce. We aimed to estimate the prevalence of NMOSD and MOGAD in the city of São Paulo, based on the known prevalence of MS. METHODS: In this observational study, we determined the total number of patients with central nervous system demyelinating disease on regular follow-up in a university referral center in São Paulo, from May 2019 to May 2021 according to the diagnosis of multiple sclerosis (MS), NMOSD and MOGAD using the current diagnostic criteria for these diseases. We used the MS: NMOSD and MS: MOGAD ratios to estimate the ratio of these diseases in São Paulo, Brazil. RESULTS: We identified 968 patients with MS, 133 patients with AQP4 positive NMOSD, and 28 patients with MOGAD. We found the MS: NMOSD ratio of 7,28 and the MS: MOGAD ratio of 34,57. We estimated a prevalence of 2,1 per 100,000 inhabitants for NMOSD and of 0,4 per 100,000 inhabitants for MOGAD. CONCLUSION: The prevalence of NMOSD is high in São Paulo, but the prevalence of MOGAD is low when compared with the prevalence found in most of the studies reported to date.