Pathogenic Potential of Eomesodermin-Expressing T-Helper Cells in Neurodegenerative Diseases.

Eomesodermin-expressing (Eomes+) T-helper (Th) cells show cytotoxic characteristics in secondary progressive multiple sclerosis. We found that Eomes+ Th cell frequency was increased in the peripheral blood of amyotrophic lateral sclerosis and Alzheimer's disease patients. Furthermore, granzyme B production by Th cells from such patients was high compared with controls. A high frequency of Eomes+ Th cells was observed in the initial (acutely progressive) stage of amyotrophic lateral sclerosis, and a positive correlation between Eomes+ Th cell frequency and cognitive decline was observed in Alzheimer's disease patients. Therefore, Eomes+ Th cells may be involved in the pathology of amyotrophic lateral sclerosis and Alzheimer's disease. ANN NEUROL 2024;95:1093-1098.

Involvement of cytotoxic Eomes-expressing CD4+ T cells in secondary progressive multiple sclerosis.

Multiple sclerosis (MS), a putative autoimmune disease of the central nervous system (CNS), commonly presents as relapsing-remitting MS (RRMS), characterized by recurrent episodes of peripheral disabling symptoms resulting from inflammatory CNS damage. Many RRMS patients transition to a chronic disease course with progressive neurological dysfunctions (secondary progressive MS, SPMS), with the progression rate varying between patients and over time. SPMS pathogenesis is now linked to immune-cell-mediated processes, although the mechanisms driving SPMS transition and progression remain elusive, and SPMS lacks biomarkers and effective treatments. We report the crucial involvement of cytotoxic CD4+ T cells expressing Eomes (Eomes+ Th cells) in SPMS pathogenesis-a Th cell subset previously identified in a mouse model of late/chronic autoimmune CNS inflammation. Few Eomes+ Th cells circulate in RRMS patient peripheral blood (n = 44), primary progressive MS (PPMS) patients (n = 25), or healthy controls (n = 42), but Eomes+ Th cells were significantly increased in SPMS (n = 105, P < 0.0001). Strikingly, lymphocytes isolated from SPMS autopsy brain samples revealed CD4+ T cells infiltrating CNS that coexpressed Eomes and the cytotoxic molecule granzyme B. In particular, the Eomes+ Th cell levels were increased in SPMS patients in progressive disease phases versus SPMS patients without current disability increases (P < 0.0001). Moreover, Eomes level acted as a biomarker to predict SPMS patients at risk of disease worsening with over 80% accuracy (ROC-AUC = 0.8276). Overall, our results indicate that granzyme B-expressing Eomes+ T helper cells are involved in the pathogenesis of SPMS, with significant implications for SPMS biomarkers and therapeutic targets.

Alterations of the gut ecological and functional microenvironment in different stages of multiple sclerosis.

Multiple sclerosis (MS), an autoimmune disease of the central nervous system, generally starts as the relapsing remitting form (RRMS), but often shifts into secondary progressive MS (SPMS). SPMS represents a more advanced stage of MS, characterized by accumulating disabilities and refractoriness to medications. The aim of this study was to clarify the microbial and functional differences in gut microbiomes of the different stages of MS. Here, we compared gut microbiomes of patients with RRMS, SPMS, and two closely related disorders with healthy controls (HCs) by 16S rRNA gene and whole metagenomic sequencing data from fecal samples and by fecal metabolites. Each patient group had a number of species having significant changes in abundance in comparison with HCs, including short-chain fatty acid (SCFA)-producing bacteria reduced in MS. Changes in some species had close association with clinical severity of the patients. A marked reduction in butyrate and propionate biosynthesis and corresponding metabolic changes were confirmed in RRMS compared with HCs. Although bacterial composition analysis showed limited differences between the patient groups, metagenomic functional data disclosed an increase in microbial genes involved in DNA mismatch repair in SPMS as compared to RRMS. Together with an increased ratio of cysteine persulfide to cysteine in SPMS revealed by sulfur metabolomics, we postulate that excessive DNA oxidation could take place in the gut of SPMS. Thus, gut ecological and functional microenvironments were significantly altered in the different stages of MS. In particular, reduced SCFA biosynthesis in RRMS and elevated oxidative level in SPMS were characteristic.

Pathogenic neuropsychiatric effect of stress-induced microglial interleukin 12/23 axis in systemic lupus erythematosus.

OBJECTIVES: The central nervous system disorder in systemic lupus erythematosus (SLE), called neuropsychiatric lupus (NPSLE), is one of the most severe phenotypes with various clinical symptoms, including mood disorder, psychosis and delirium as diffuse neuropsychological manifestations (dNPSLE). Although stress is one of the aggravating factors for neuropsychiatric symptoms, its role in the pathogenesis of dNPSLE remains to be elucidated. We aimed to investigate stress effects on the neuropsychiatric pathophysiology in SLE using lupus-prone mice and patients' data. METHODS: Sleep disturbance stress (SDS) for 2 weeks was placed on 6-8-week-old female MRL/lpr and control mice. Behavioural phenotyping, histopathological analyses and gene and protein expression analyses were performed to assess SDS-induced neuroimmunological alterations. We also evaluated cytokines of the cerebrospinal fluid and brain regional volumes in patients with dNPSLE and patients with non-dNPSLE. RESULTS: SDS-subjected MRL/lpr mice exhibited less anxiety-like behaviour, whereas stressed control mice showed increased anxiety. Furthermore, stress strongly activated the medial prefrontal cortex (mPFC) in SDS-subjected MRL/lpr. A transcriptome analysis of the PFC revealed the upregulation of microglial activation-related genes, including Il12b. We confirmed that stress-induced microglial activation and the upregulation of interleukin (IL) 12/23p40 proteins and increased dendritic spines in the mPFC of stressed MRL/lpr mice. IL-12/23p40 neutralisation and tyrosine kinase 2 inhibition mitigated the stress-induced neuropsychiatric phenotypes of MRL/lpr mice. We also found a higher level of cerebrospinal fluid IL-12/23p40 and more atrophy in the mPFC of patients with dNPSLE than those with non-dNPSLE. CONCLUSIONS: The microglial IL-12/23 axis in the mPFC might be associated with the pathogenesis and a promising therapeutic target for dNPSLE.

Th1 - CD11c+ B Cell Axis Associated with Response to Plasmapheresis in Multiple Sclerosis.

OBJECTIVE: Although plasmapheresis is a treatment option for patients with autoimmune neurological diseases, treatment response varies greatly among patients. The main objective of this study was to find out if biological/immune traits correlate with a beneficial response. METHODS: We thoroughly analyzed immune phenotypes in paired blood samples from a cohort of 31 patients with multiple sclerosis before and after plasmapheresis, in parallel with clinical evaluation of treatment response. RESULTS: The frequency of IFN-γ+ Th1 cells was persistently higher in those who obtained benefit from plasmapheresis (responders) than nonresponders. The Th1 cell frequency before plasmapheresis provided a high predictive value for beneficial response, achieving area under the curve (AUC) of 0.902. Plasmapheresis treatment decreased inflammation-related gene expressions in Th1 cells. Meanwhile, IFNG expression in Th1 cells positively correlated with the frequency of CD11c+ B cells, of which a pathogenic role has been suggested in several autoimmune diseases. In line with this, in vitro experiments showed that CD11c+ B cells would increase in response to exogenous IFN-γ compared to IL-4, and secrete high amounts of IgG. B cell receptor analysis indicated that clonal expansion of CD11c+ B cells takes place in patients with multiple sclerosis. Interestingly, CD11c+ B cells, which showed unique gene expression profile, decreased after plasmapheresis treatment along with all the immunoglobulin subsets in the circulation. INTERPRETATION: Taken together, we postulate that Th1 cell - CD11c+ B cell axis is involved in treatment response to plasmapheresis, giving us clues to better understanding of complicated pathogenesis of autoimmune diseases, and getting closer to a personalized therapy. ANN NEUROL 2021;90:595-611.

Skewing of the B cell receptor repertoire in myalgic encephalomyelitis/chronic fatigue syndrome.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition characterized by fatigue and post-exertional malaise, accompanied by various signs of neurological and autonomic dysfunction. ME/CFS is often triggered by an infectious episode and associated with an aberrant immune system. Here we report that ME/CFS is a disorder characterized by skewed B cell receptor gene usage. By applying a next-generation sequencing to determine the clone-based IGHV/IGHD/IGHJ repertoires, we revealed a biased usage of several IGHV genes in peripheral blood B cells from ME/CFS patients. Results of receiver operating characteristic (ROC) analysis further indicated a possibility of distinguishing patients from healthy controls, based on the skewed B cell repertoire. Meanwhile, B cell clones using IGHV3-30 and IGHV3-30-3 genes were more frequent in patients with an obvious infection-related episode at onset, and correlated to expression levels of interferon response genes in plasmablasts. Collectively, these results imply that B cell responses in ME/CFS are directed against an infectious agents or priming antigens induced before disease onset.

Gut microbiota-dependent CCR9+CD4+ T cells are altered in secondary progressive multiple sclerosis.

The mechanism underlying the progression of relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis (SPMS), characterized by accumulating fixed disability, is yet to be fully understood. Although alterations in the gut microbiota have recently been highlighted in multiple sclerosis pathogenesis, the mechanism linking the altered gut environment with the remote CNS pathology remains unclear. Here, we analyse human CD4+ memory T cells expressing the gut-homing chemokine receptor CCR9 and found a reduced frequency of CCR9+ memory T cells in the peripheral blood of patients with SPMS relative to healthy controls. The reduction in the proportion of CCR9+ cells among CD4+ memory T cells (%CCR9) in SPMS did not correlate with age, disease duration or expanded disability status scale score, although %CCR9 decreased linearly with age in healthy controls. During the clinical relapse of both, relapsing-remitting multiple sclerosis and neuromyelitis optica, a high proportion of cells expressing the lymphocyte activating 3 gene (LAG3) was detected among CCR9+ memory T cells isolated from the CSF, similar to that observed for mouse regulatory intraepithelial lymphocytes. In healthy individuals, CCR9+ memory T cells expressed higher levels of CCR6, a CNS-homing chemokine receptor, and exhibited a regulatory profile characterized by both the expression of C-MAF and the production of IL-4 and IL-10. However, in CCR9+ memory T cells, the expression of RORγt was specifically upregulated, and the production of IL-17A and IFNγ was high in patients with SPMS, indicating a loss of regulatory function. The evaluation of other cytokines supported the finding that CCR9+ memory T cells acquire a more inflammatory profile in SPMS, reporting similar aspects to CCR9+ memory T cells of the elderly healthy controls. CCR9+ memory T cell frequency decreased in germ-free mice, whereas antibiotic treatment increased their number in specific pathogen-free conditions. Here, we also demonstrate that CCR9+ memory T cells preferentially infiltrate into the inflamed CNS resulting from the initial phase and that they express LAG3 in the late phase in the experimental autoimmune encephalomyelitis mouse model of multiple sclerosis. Antibiotic treatment reduced experimental autoimmune encephalomyelitis symptoms and was accompanied by an increase in CCR9+ memory T cells in the peripheral blood. Antibodies against mucosal vascular addressin cell adhesion molecule 1 (MADCAM1), which is capable of blocking cell migration to the gut, also ameliorated experimental autoimmune encephalomyelitis. Overall, we postulate that the alterations in CCR9+ memory T cells observed, caused by either the gut microbiota changes or ageing, may lead to the development of SPMS.

Correction: PLA2G6-associated neurodegeneration presenting as a complicated form of hereditary spastic paraplegia.

The originally published version of this article contained an error in Fig. 1 and Table 2. The correct figure and table of this article should have read as below. This has now been corrected in the PDF and HTML versions of the article. The authors apologize for any inconvenience caused.

PLA2G6-associated neurodegeneration presenting as a complicated form of hereditary spastic paraplegia.

PLA2G6-associated neurodegeneration (PLAN) comprises heterogeneous neurodegenerative disorders, including infantile neuroaxonal dystrophy, neurodegeneration with brain iron accumulation 2B, and Parkinson disease 14 (PARK14). In addition, very recently, PLA2G6 mutations have been reported to represent a phenotype of hereditary spastic paraplegia (HSP). In this study, we screened 383 HSP families to clarify the frequency of PLA2G6 mutations in the Japan Spastic Paraplegia Research Consortium, and revealed the clinical characteristics of HSP with PLA2G6 mutations. We found three families with compound heterozygous mutations of the PLA2G6 gene, c.517 C > T/c.1634A > G, c.662 T > C/c.991 G > T, and c.1187-2 A > G/c.1933C > T, and one family with a homozygous mutation of the PLA2G6 gene, c.1904G > A/c.1904G > A. All three families with compound heterozygous mutations presented a uniform phenotype of a complicated form of HSP with infantile/child-onset spastic paraplegia, cerebellar ataxia, and mental retardation. On the other hand, the family with a homozygous mutation presented a late-onset complicated form of HSP with parkinsonism. This study may extend the clinical and genetic findings for PLAN.

Brain abnormalities in myalgic encephalomyelitis/chronic fatigue syndrome: Evaluation by diffusional kurtosis imaging and neurite orientation dispersion and density imaging.

BACKGROUND: Diffusional kurtosis imaging (DKI) and neurite orientation dispersion and density imaging (NODDI) metrics provide more specific information regarding pathological changes than diffusion tensor imaging (DTI). PURPOSE: To detect microstructural abnormalities in myalgic encephalomyelitis (ME) / chronic fatigue syndrome (CFS) patients by using DKI and NODDI metrics. STUDY TYPE: Prospective. POPULATION: Twenty ME/CFS patients and 23 healthy controls were recruited. FIELD STRENGTH/SEQUENCE: Three-b value DWI (b-values = 0, 1000, and 2000 sec/mm2 ) and 3D T1 -weighted images were at 3.0T. ASSESSMENT: Mean kurtosis (MK), neurite density index (NDI), orientation dispersion index (ODI), fractional anisotropy (FA), and mean diffusivity (MD) were calculated. STATISTICAL TESTING: The two-sample t-test analysis in SPM12 software was used to compare the differences between ME/CFS and control groups. RESULTS: In the ME/CFS patients, we observed significant FA decreases in the genu of the corpus callosum and the anterior limb of the right internal capsule (P < 0.05), but no significant difference in MD (P = 0.164); there were also significant MK decreases in the right frontal area, anterior cingulate gyrus, superior longitudinal fasciculus (SLF), and left parietal area (P < 0.05). Significant NDI decreases were observed in the right posterior cingulate gyrus, SLF, and left frontal area of the ME/CFS patients (P < 0.05). Significant ODI decreases were seen in the bilateral occipital areas, right superior temporal gyrus, the anterior limb of internal capsule, and the posterior cingulate gyrus (P < 0.05), and significant ODI increases were revealed in the bilateral occipital and right temporal areas (P < 0.05). DATA CONCLUSION: Right SLF abnormalities may be a diagnostic marker for ME/CFS. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:818-824.

Differential effects of fingolimod on B-cell populations in multiple sclerosis.

BACKGROUND: Fingolimod is an oral drug approved for multiple sclerosis (MS) with an ability to trap central memory T cells in secondary lymphoid tissues; however, its variable effectiveness in individual patients indicates the need to evaluate its effects on other lymphoid cells. OBJECTIVE: To clarify the effects of fingolimod on B-cell populations in patients with MS. METHODS: We analysed blood samples from 9 fingolimod-treated and 19 control patients with MS by flow cytometry, to determine the frequencies and activation states of naive B cells, memory B cells, and plasmablasts. RESULTS: The frequencies of each B-cell population in peripheral blood mononuclear cells (PBMC) were greatly reduced 2 weeks after starting fingolimod treatment. Detailed analysis revealed a significant reduction in activated memory B cells (CD38(int-high)), particularly those expressing Ki-67, a marker of cell proliferation. Also, we noted an increased proportion of activated plasmablasts (CD138(+)) among whole plasmablasts, in the patients treated with fingolimod. CONCLUSIONS: The marked reduction of Ki-67(+) memory B cells may be directly linked with the effectiveness of fingolimod in treating MS. In contrast, the relative resistance of CD138(+) plasmablasts to fingolimod may be of relevance for understanding the differential effectiveness of fingolimod in individual patients.

CCR2(+)CCR5(+) T cells produce matrix metalloproteinase-9 and osteopontin in the pathogenesis of multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating disease of the CNS that is presumably mediated by CD4(+) autoimmune T cells. Although both Th1 and Th17 cells have the potential to cause inflammatory CNS pathology in rodents, the identity of pathogenic T cells remains unclear in human MS. Given that each Th cell subset preferentially expresses specific chemokine receptors, we were interested to know whether T cells defined by a particular chemokine receptor profile play an active role in the pathogenesis of MS. In this article, we report that CCR2(+)CCR5(+) T cells constitute a unique population selectively enriched in the cerebrospinal fluid of MS patients during relapse but not in patients with other neurologic diseases. After polyclonal stimulation, the CCR2(+)CCR5(+) T cells exhibited a distinct ability to produce matrix metalloproteinase-9 and osteopontin, which are involved in the CNS pathology of MS. Furthermore, after TCR stimulation, the CCR2(+)CCR5(+) T cells showed a higher invasive potential across an in vitro blood-brain barrier model compared with other T cells. Of note, the CCR2(+)CCR5(+) T cells from MS patients in relapse are reactive to myelin basic protein, as assessed by production of IFN-γ. We also demonstrated that the CCR6(-), but not the CCR6(+), population within CCR2(+)CCR5(+) T cells was highly enriched in the cerebrospinal fluid during MS relapse (p < 0.0005) and expressed higher levels of IFN-γ and matrix metalloproteinase-9. Taken together, we propose that autoimmune CCR2(+)CCR5(+)CCR6(-) Th1 cells play a crucial role in the pathogenesis of MS.

Interleukin 6 signaling promotes anti-aquaporin 4 autoantibody production from plasmablasts in neuromyelitis optica.

Neuromyelitis optica (NMO) is an inflammatory disease affecting the optic nerve and spinal cord, in which autoantibodies against aquaporin 4 (AQP4) water channel protein probably play a pathogenic role. Here we show that a B-cell subpopulation, exhibiting the CD19(int)CD27(high)CD38(high)CD180(-) phenotype, is selectively increased in the peripheral blood of NMO patients and that anti-AQP4 antibodies (AQP4-Abs) are mainly produced by these cells in the blood of these patients. These B cells showed the morphological as well as the phenotypical characteristics of plasmablasts (PB) and were further expanded during NMO relapse. We also demonstrate that interleukin 6 (IL-6), shown to be increased in NMO, enhanced the survival of PB as well as their AQP4-Ab secretion, whereas the blockade of IL-6 receptor (IL-6R) signaling by anti-IL-6R antibody reduced the survival of PB in vitro. These results indicate that the IL-6-dependent B-cell subpopulation is involved in the pathogenesis of NMO, thereby providing a therapeutic strategy for targeting IL-6R signaling.

High frequency of circulating non-classical monocytes is associated with stable remission in relapsing-remitting multiple sclerosis.

'No evidence of disease activity (NEDA)', judged by clinical and radiological findings, is a therapeutic goal in patients with multiple sclerosis (MS). It is, however, unclear if distinct biological mechanisms contribute to the maintenance of NEDA. To clarify the immunological background of long-term disease stability defined by NEDA, circulating immune cell subsets in patients with relapsing-remitting MS (RRMS) were analyzed using flow cytometry. Patients showing long-term NEDA (n = 31) had significantly higher frequencies of non-classical monocytes (NCMs) (6.1% vs 1.4%) and activated regulatory T cells (Tregs; 2.1% vs 1.6%) than those with evidence of disease activity (n = 8). The NCM frequency and NCMs to classical monocytes ratio (NCM/CM) positively correlated with activated Treg frequency and duration of NEDA. Co-culture assays demonstrated that NCMs could increase the frequency of activated Tregs and the expression of PD-L1, contributing to development of Tregs, was particularly high in NCMs from patients with NEDA. Collectively, NCMs contribute to stable remission in patients with RRMS, possibly by increasing activated Treg frequency. In addition, the NCM frequency and NCM/CM ratio had high predictive values for disease stability (AUC = 0.97 and 0.94, respectively), suggesting these markers are potential predictors of a long-term NEDA status in RRMS.

Efficacy and Safety of the Natural Killer T Cell-Stimulatory Glycolipid OCH-NCNP1 for Patients With Relapsing Multiple Sclerosis: Protocol for a Randomized Placebo-Controlled Clinical Trial.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system that causes myelin sheath damage and axonal degeneration. The glycolipid (2S, 3S, 4R)-1-O-(α-d-galactosyl)-2-tetracosanoylamino-1,3,4-nonaetriol (OCH-NCNP1 or OCH) exerts an immunoregulatory action that suppresses T helper (Th)1 cell-mediated immune responses through natural killer T cell activation, selective interleukin-4 production, and Th2 bias induction in human CD4-positive natural killer T cells. OBJECTIVE: This trial aims to investigate the efficacy and safety of the immunomodulator OCH in patients with relapsing MS through 24-week repeated administration. METHODS: This protocol describes a double-blind, multicenter, placebo-controlled, randomized phase II clinical trial that was initiated in September 2019. The participants were randomly assigned to either a placebo control group or an OCH-NCNP1 group and the investigational drug (3.0 mg) was orally administered once weekly for the 24-week duration. Major inclusion criteria are as follows: patients had been diagnosed with relapsing MS (relapsing-remitting and/or secondary progressive MS) based on the revised McDonald criteria or were diagnosed with MS by an attending physician as noted in their medical records; patients with at least two medically confirmed clinical exacerbations within 24 months prior to consent or one exacerbation within 12 months prior to consent; patients with at least one lesion suspected to be MS on screening magnetic resonance imaging (MRI); and patients with 7 points or less in the Expanded Disability Status Scale during screening. Major exclusion criteria are as follows: diagnosis of neuromyelitis optica and one of optic neuritis, acute myelitis, and satisfying at least two of the following three items: (1) spinal cord MRI lesion extending across at least three vertebral bodies, (2) no brain MRI lesions during onset (at least four cerebral white matter lesions or three lesions, one of which is around the lateral ventricle), and (3) neuromyelitis optica-immunoglobulin G or antiaquaporin-4 antibody-positive. Outcome measures include the primary outcome of MRI changes (the percentage of subjects with new or newly expanded lesions at 24 weeks on T2-weighted MRI) and the secondary outcomes annual relapse rate (number of recurrences per year), relapse-free period (time to recurrence), sustained reduction in disability (SRD) occurrence rate, period until SRD (time to SRD occurrence), no evidence of disease activity, and exploratory biomarkers from phase I trials (such as gene expression, cell frequency, and intestinal and oral microbiome). RESULTS: We plan to enroll 30 patients in the full analysis set. Enrollment was closed in June 2021 and the study analysis was completed in March 2023. CONCLUSIONS: This randomized controlled trial will determine whether OCH-NCNP1 is effective and safe in patients with MS as well as provide evidence for the potential of OCH-NCNP1 as a therapeutic agent for MS. TRIAL REGISTRATION: ClinicalTrials.gov NCT04211740; https://clinicaltrials.gov/study/NCT04211740. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/46709.

'Grasshopper sign': the novel imaging of post-COVID-19 myelopathy with delayed longitudinal white matter abnormalities.

Introduction: Recently, there have been a few reports of atypical post-coronavirus disease 2019 (COVID-19) myelopathy manifesting tract-specific lesions similar to those due to vitamin B12 deficiency. However, the precise characteristics of imaging or clinical course remain not well understood. Methods: A retrospective analysis of the clinical and imaging characteristics of four patients who were referred to our hospital with a unique post-COVID-19 myelopathy was performed. Results: Four-to-six weeks following COVID-19 infection in the summer of 2023, four middle-aged men developed paraparesis, hypo/dysesthesia and bladder/bowel disturbance, suggesting myelopathy. Although spinal MRI showed no abnormalities in the early stages, tract-specific longitudinal lesions along the dorsal and lateral columns became apparent as the symptoms progressed. Owing to the lack of MRI findings at the early stage, all cases were challenging to diagnose. However, the patients remained partially responsive to aggressive immunosuppressive therapies, even in the advanced stage. Discussion: We termed these tract-specific longitudinal lesions in the presented case series 'Grasshopper sign' because brain coronal and spine axial MRI findings looked like a grasshopper's antennae and face. Early identification of the characteristic MRI abnormality could allow for early intervention using intensive immunosuppressive therapy, which could improve patient outcomes.

CD11chigh B Cell Expansion Is Associated With Severity and Brain Atrophy in Neuromyelitis Optica.

BACKGROUND AND OBJECTIVES: Neuromyelitis optica (NMO) is an autoimmune astrocytopathy mediated by anti-AQP4 antibody-producing B cells. Recently, a B-cell subset highly expressing CD11c and T-bet, originally identified as age-associated B cells, has been shown to be involved in the pathogenesis of various autoimmune diseases. The objective of this study was to determine the relationship between the frequency of CD11chigh B cells per CD19+ B cells in the peripheral blood of patients with NMO and the clinical profiles including the brain volume. METHODS: In this observational study, 45 patients with anti-AQP4 antibody-positive NMO in remission and 30 healthy control subjects (HCs) were enrolled. Freshly isolated peripheral blood mononuclear cells were analyzed for immune cell phenotypes. The frequency of CD11chigh B cells per CD19+ B cells was assessed by flow cytometry and was evaluated in association with the clinical profiles of patients. Brain MRI data from 26 patients were included in the study for the analysis on the correlation between CD11chigh B-cell frequency and brain atrophy. RESULTS: We found that the frequency of CD11chigh B cells in CD19+ B cells was significantly increased in patients with NMO compared with HCs. The expansion of CD11chigh B cells significantly correlated with EDSS, past relapse numbers, and disease duration. In addition, a higher frequency of CD11chigh B cells negatively correlated with total brain, white matter, and gray matter volumes and positively correlated with T2/FLAIR high lesion volumes. When the past clinical relapse episodes of patients with or without the expansion of CD11chigh B cells were compared, relapses in the brain occurred more frequently in patients with CD11chigh B-cell expansion. CD11chigh B cells had distinct features including expression of chemokine receptors associated with migration into peripheral inflammatory tissues and antigen presentation. CD11chigh B-cell frequency was positively correlated with T peripheral helper-1 (Tph-1) cell frequency. DISCUSSION: Even during the relapse-free period, CD11chigh B cells could expand in the long disease context, possibly through the interaction with Tph-1 cells. The increased frequency of CD11chigh B cells associated with brain atrophy and disease severity, indicating that this cell population could be involved in chronic neuroinflammation in NMO.

Multimodal imaging analyses in neuromyelitis optica spectrum disorder with or without visual disturbance.

BACKGROUND AND PURPOSE: Neuromyelitis optica spectrum disorder is a demyelinating and inflammatory affliction that often leads to visual disturbance. Various imaging techniques, including free-water imaging, have been used to determine neuroinflammation and degeneration. Therefore, this study aimed at determining multimodal imaging differences between patients with neuromyelitis optica spectrum disorder, especially those with visual disturbance, and healthy controls. MATERIALS AND METHODS: Eighty-five neuromyelitis optica spectrum disorder patients and 89 age- and sex-matched healthy controls underwent 3-T magnetic resonance imaging (MRI). We analyzed adjusted brain-predicted age difference, voxel-based morphometry, and free-water-corrected diffusion tensor imaging (DTI) by tract-based spatial statistics in each patient group (MRI-positive/negative neuromyelitis optica spectrum disorder patients with or without a history of visual disturbance) compared with the healthy control group. RESULTS: MRI-positive neuromyelitis optica spectrum disorder patients exhibited reduced volumes of the bilateral thalamus. Tract-based spatial statistics showed diffuse white matter abnormalities in all DTI metrics in MRI-positive neuromyelitis optica spectrum disorder patients with a history of visual disturbance. In MRI-negative neuromyelitis optica spectrum disorder patients with a history of visual disturbance, voxel-based morphometry showed volume reduction of bilateral thalami and optic radiations, and tract-based spatial statistics revealed significantly lower free-water-corrected fractional anisotropy and higher mean diffusivity in the posterior dominant distributions, including the optic nerve radiation. CONCLUSION: Free-water-corrected DTI and voxel-based morphometry analyses may reflect symptoms of visual disturbance in neuromyelitis optica spectrum disorder.

[Myalgic Encephalitis/Chronic Fatigue Syndrome: Diagnostic and Therapeutic Approach and Biological Research].

Myalgic encephalitis/chronic fatigue syndrome, an intractable disease characterized by profound fatigue, sleep disturbance, cognitive impairment, and orthostatic intolerance, among other features, often occurs after infectious episodes. Patients experience various types of chronic pain; however, post-exertional malaise is the most significant feature, which requires pacing. In this article, I summarize the current diagnostic and therapeutic approaches and describe recent biological research in this domain.

Brain-regional characteristics and neuroinflammation in ME/CFS patients from neuroimaging: A systematic review and meta-analysis.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition characterized by an elusive etiology and pathophysiology. This study aims to evaluate the pathological role of neuroinflammation in ME/CFS by conducting an exhaustive analysis of 65 observational studies. Four neuroimaging techniques, including magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), electroencephalography (EEG), and positron emission tomography (PET), were employed to comparatively assess brain regional structure, metabolite profiles, electrical activity, and glial activity in 1529 ME/CFS patients (277 males, 1252 females) and 1715 controls (469 males, 1246 females). Clinical characteristics, including sex, age, and fatigue severity, were consistent with established epidemiological patterns. Regional alterations were most frequently identified in the cerebral cortex, with a notable focus on the frontal cortex. However, our meta-analysis data revealed a significant hypoactivity in the insular and thalamic regions, contrary to observed frequencies. These abnormalities, occurring in pivotal network hubs bridging reason and emotion, disrupt connections with the limbic system, contributing to the hallmark symptoms of ME/CFS. Furthermore, we discuss the regions where neuroinflammatory features are frequently observed and address critical neuroimaging limitations, including issues related to inter-rater reliability. This systematic review serves as a valuable guide for defining regions of interest (ROI) in future neuroimaging investigations of ME/CFS.