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.

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.

Eomesodermin-expressing CD4+ Th cells and association with pregnancy in multiple sclerosis

Background

Pregnancy in patients with multiple sclerosis (MS) is accompanied by a decline of relapse activity with increased risk of relapses 3 months post-partum, for unknown reasons. Eomesodermin+ T-helper cells (Eomes+ Th cells) are known to mediate neuroinflammation and disease progression in MS and are induced by prolactin-secreting cells.

Objectives

Here, investigated immune cell alterations and the pathophysiological role of Eomes+ Th cells for disease activity during pregnancy and post-partum in MS.

Methods

We enrolled n = 81 pregnant patients with relapsing-remitting MS (RRMS), n = 27 post-partum RRMS and n = 26 female RRMS control patients under the umbrella of the German Multiple Sclerosis and Pregnancy Registry. Clinical data were collected and immune cell alterations were analysed using flow cytometry.

Results

While CD3+CD4+ Th cells were unaffected, CD3+CD8+ cytotoxic T-cells were elevated post-partum (p = 0.02) with reduced B-cell frequencies (p = 0.01) compared to non-pregnant RRMS patients. NK cells were elevated during first trimester (p = 0.02) compared to the third trimester. Frequencies of Eomes+ Th and Eomes+ Tc cells did not differ. There was no correlation of prolactin release and expression of Eomes+ Th cells. However, Eomes+ Th cells correlated with lower frequencies of regulatory T-cells during second (r = -0.42; p < 0.05) and third trimester (r = -0.37; p < 0.05). Moreover, Eomes+ Th cells correlated with frequencies of B-cells during third trimester (r = 0.54; p = 0.02). Frequencies of Eomes+ Th cells were not associated with the number of relapses before pregnancy, during pregnancy or post-partum. However, Eomes+ Th cells strongly correlated with disability post-partum as assessed using the EDSS (r = 0.52; p = 0.009).

Discussion

Pregnancy in MS is associated with robust immunological alterations. Eomes+ Th cells are capable of inducing immune cell alterations during the course of pregnancy, most evident during the second and third trimester as shown with a correlation of reduced Treg cells and a significant increase of B-cells. Importantly, Eomes+ Th cells correlate with disability post-partum. In summary, during late pregnancy in MS an inflammatory, cytotoxic and dysregulated immunological environment is primed gaining function post-delivery. This may be responsible for post-partum disability accumulation.

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.

Resident Memory-like CD8+ T Cells Are Involved in Chronic Inflammatory and Neurodegenerative Diseases in the CNS

BACKGROUND AND OBJECTIVES

Resident memory T (Trm) cells are a unique population that can survive and function in a compartmentalized tissue with inflammatory potential. We aim to investigate the alteration of Trm population in acute/chronic inflammatory and neurodegenerative diseases in the CNS.

METHODS

The frequencies of CD4+ and CD8+ T cells expressing both CD69 and CD103, the markers for Trm cells, were quantified in the peripheral blood and CSF (n = 80 and 44, respectively) in a cross-sectional manner. The transcriptional profile of Trm-like population in the CSF was further analyzed using a public single-cell dataset.

RESULTS

The frequency of CD69+CD103+CD8+ T cells was strikingly higher in the CSF than in the peripheral blood (among memory fraction, 13.5% vs 0.11%, difference (mean [SE]): 13.4% [2.9]). This CD69+CD103+CD8+ T-cell population was increased in the CSF from patients with chronic inflammatory diseases including multiple sclerosis and with neurodegenerative diseases such as Parkinson disease and Alzheimer disease compared with controls (11.5%, 13.0%, 8.1% vs 2.9%, respectively). By contrast, the frequency was not altered in acute inflammatory conditions in the CNS (4.0%). Single-cell RNAseq analysis confirmed Trm signature in CD69+CD103+CD8+ T cells in the CSF, supporting their Trm-like phenotype, which was not clear in controls.

DISCUSSION

Collectively, an increase in CD69+CD103+CD8+ Trm-like population in the CSF is related with both chronic neuroinflammatory and some neurodegenerative diseases in the CNS, suggesting a partially shared pathology in these diseases.

Long-term Effects of IL-6 Receptor Blockade Therapy on Regulatory Lymphocytes and Neutrophils in Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVES

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune neurologic disease. Anti-IL-6 receptor (IL-6R) therapy prevents relapses in patients with anti-aquaporin 4 (AQP4)-IgG-positive NMOSD; however, it remains unclear how cellular immune components are altered by anti-IL-6R therapy. In this study, we examined the long-term effects of the anti-IL-6R monoclonal antibody tocilizumab (TCZ) on immune cell profiles in patients with NMOSD.

METHODS

Monthly IV injections of TCZ (8 mg/kg) were administered as an add-on therapy to 19 anti-AQP4-IgG-positive patients, who had been refractory to corticosteroids and immunosuppressive drugs. Peripheral blood was collected before infusion of TCZ for flow cytometry analysis of lymphocyte subsets. Seven patients provided whole blood samples for gene expression profiles.

RESULTS

Patients with NMOSD had reduced numbers of lymphocyte subsets with regulatory functions, including transitional B cells, CD56high NK cells, and CD45RA-FoxP3high regulatory T cells. However, after initiating TCZ therapy, the numbers increased to normal levels within 1 year. Gene expression analysis revealed that neutrophil granule-related genes, predominated by those related to azurophil granules, were significantly upregulated in patients with NMOSD. Such alterations suggestive of accelerated myeloid turnover were not observed 1 year after TCZ therapy, and the effects of TCZ on some neutrophil genes were observed as early as 5 days after starting TCZ. In vitro analysis demonstrated that naïve T-cell division was impaired in the enrolled patients, which was fully recovered after 18 months of therapy.

DISCUSSION

In patients with active NMOSD not treated with molecular targeting drugs, we observed reduction or deficiency in lymphocytes with regulatory potentials and activation of neutrophils. However, introduction of anti-IL-6R therapy accompanied by tapering concomitant drugs corrected such abnormalities, which might contribute to persistent relapse prevention. The recovery in the naïve T-cell division after starting TCZ may underlie the relatively low risk of infection in patients under anti-IL-6R therapy.

TRIAL REGISTRATION INFORMATION

University Hospital Medical Information Network Clinical Trials Registry: UMIN000005889 (July 8, 2011) and UMIN000007866 (May 1, 2012) (umin.ac.jp/ctr/index.htm). The first participant was enrolled on November 2, 2011.

Exploring the Potential of the Corpus Callosum Area as a Predictive Marker for Impaired Information Processing in Multiple Sclerosis

Early cognitive impairment (CI) detection is crucial in multiple sclerosis (MS). However, it can progress silently regardless of relapse activity and reach an advanced stage. We aimed to determine whether the corpus callosum area (CCA) is a sensitive and feasible marker for CI in MS compared to other neuroimaging markers. We assessed cognitive function in 77 MS patients using the Symbol Digit Modalities Test, Paced Auditory Serial Additions Task, Wechsler Adult Intelligence Scale-IV, and Wechsler Memory Scale-Revised. The neuroimaging markers included manually measured CCA, two diffusion tensor imaging markers, and nine volumetric measurements. Apart from volumes of the hippocampus and cerebellum, ten markers showed a significant correlation with all neuropsychological tests and significant differences between the groups. The normalized CCA demonstrated a moderate-to-strong correlation with all neuropsychological tests and successfully differentiated between the CI and cognitively normal groups with 80% sensitivity and 83% specificity. The marker had a large area under the curve and a high Youden index (0.82 and 0.63, respectively) and comparability with established cognitive markers. Therefore, the normalized CCA may serve as a reliable marker for CI in MS and can be easily implemented in clinical practice, providing a supportive diagnostic tool for CI in MS.

Harnessing autoimmunity with dominant self-peptide: Modulating the sustainability of tissue-preferential antigen-specific Tregs by governing the binding stability via peptide flanking residues

Sensitization to self-peptides induces various immunological responses, from autoimmunity to tumor immunity, depending on the peptide sequence; however, the underlying mechanisms remain unclear, and thus, curative therapeutic options considering immunity balance are limited. Herein, two overlapping dominant peptides of myelin proteolipid protein, PLP136-150 and PLP139-151, which induce different forms of experimental autoimmune encephalomyelitis (EAE), monophasic and relapsing EAE, respectively, were investigated. Mice with monophasic EAE exhibited highly resistant to EAE re-induction with any encephalitogenic peptides, whereas mice with relapsing EAE were susceptible, and progressed, to EAE re-induction. This resistance to relapse and re-induction in monophasic EAE mice was associated with the maintenance of potent CD69+CD103+CD4+CD25high regulatory T-cells (Tregs) enriched with antigen specificity, which expanded preferentially in the central nervous system with sustained suppressive activity. This tissue-preferential sustainability of potent antigen-specific Tregs was correlated with the antigenicity of PLP136-150, depending on its flanking residues. That is, the flanking residues of PLP136-150 enable to form pivotally arranged strong hydrogen bonds that secured its binding stability to MHC-class II. These potent Tregs acting tissue-preferentially were induced only by sensitization of PLP136-150, not by its tolerance induction, independent of EAE development. These findings suggest that, for optimal therapy, "benign autoimmunity" can be critically achieved through inverse vaccination with self-peptides by manipulating their flanking residues.

Free-water-corrected diffusion and adrenergic/muscarinic antibodies in myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND AND PURPOSE

Free-water-corrected diffusion tensor imaging (FW-DTI), a new analysis method for diffusion MRI, can indicate neuroinflammation and degeneration. There is increasing evidence of autoimmune etiology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We used FW-DTI and conventional DTI to investigate microstructural brain changes related to autoantibody titers in patients with ME/CFS.

METHODS

We prospectively examined 58 consecutive right-handed ME/CFS patients who underwent both brain MRI including FW-DTI and a blood analysis of autoantibody titers against β1 adrenergic receptor (β1 AdR-Ab), β2 AdR-Ab, M3 acetylcholine receptor (M3 AchR-Ab), and M4 AchR-Ab. We investigated the correlations between these four autoantibody titers and three FW-DTI indices-free water (FW), FW-corrected fractional anisotropy (FAt), and FW-corrected mean diffusivity-as well as two conventional DTI indices-fractional anisotropy (FA) and mean diffusivity. The patients' age and gender were considered as nuisance covariates. We also evaluated the correlations between the FW-DTI indices and the performance status and disease duration.

RESULTS

Significant negative correlations between the serum levels of several autoantibody titers and DTI indices were identified, mainly in the right frontal operculum. The disease duration showed significant negative correlations with both FAt and FA in the right frontal operculum. The changes in the FW-corrected DTI indices were observed over a wider extent compared to the conventional DTI indices.

CONCLUSIONS

These results demonstrate the value of using DTI to assess the microstructure of ME/CFS. The abnormalities of right frontal operculum may be a diagnostic marker for ME/CFS.

Continuous acceleration of neural activity of the GnRH pulse generator during chronic peripheral infusion of neurokinin 3 receptor agonist in goats

Secretion of pulsatile gonadotropin-releasing hormone (GnRH) is essential for reproduction. Kisspeptin neurons in the arcuate nucleus (ARC), which coexpress neurokinin B (NKB) and its receptor (NK3R), are believed to be components of the GnRH pulse generator that regulates pulsatile GnRH secretion. We examined the effects of peripheral infusion of senktide, an NK3R selective agonist, on GnRH pulse generator activity by monitoring multiple unit activity (MUA) in the goat ARC. Previous studies have shown that characteristic increases in MUA (MUA volleys) reflect GnRH pulse generator activity. Senktide was infused intravenously or intravaginally for 2 h while recording MUA. Both infusions significantly increased the MUA volley frequency compared with the control. These results demonstrate that peripherally administered senktide acts centrally to sustainably accelerate the neural activity of the GnRH pulse generator throughout the infusion period. This suggests the possibility of practical applications of NK3R agonists for improving reproductive activity in farm animals.

Pathogenic Microglia Orchestrate Neurotoxic Properties of Eomes-Expressing Helper T Cells

In addition to disease-associated microglia (DAM), microglia with MHC-II and/or IFN-I signatures may form additional pathogenic subsets that are relevant to neurodegeneration. However, the significance of such MHC-II and IFN-I signatures remains elusive. We demonstrate here that these microglial subsets play intrinsic roles in orchestrating neurotoxic properties of neurotoxic Eomes+ Th cells under the neurodegeneration-associated phase of experimental autoimmune encephalomyelitis (EAE) that corresponds to progressive multiple sclerosis (MS). Microglia acquire IFN-signature after sensing ectopically expressed long interspersed nuclear element-1 (L1) gene. Furthermore, ORF1, an L1-encoded protein aberrantly expressed in the diseased central nervous system (CNS), stimulated Eomes+ Th cells after Trem2-dependent ingestion and presentation in MHC-II context by microglia. Interestingly, administration of an L1 inhibitor significantly ameliorated neurodegenerative symptoms of EAE concomitant with reduced accumulation of Eomes+ Th cells in the CNS. Collectively, our data highlight a critical contribution of new microglia subsets as a neuroinflammatory hub in immune-mediated neurodegeneration.

Ratio of lymphocyte to monocyte area under the curve as a novel predictive factor for severe infection in multiple sclerosis

Background

Individuals with multiple sclerosis (MS) are vulnerable to all types of infection, because MS itself involves immunodeficiency, in addition to involving treatment with immunosuppressants. Simple predictive variables for infection that are easily assessed in daily examinations are warranted. Lymphocyte area under the curve (L_AUC), defined as the sum of serial absolute lymphocyte counts under the lymphocyte count-time curve, has been established as a predictive factor for several infections after allogenic hematopoietic stem cell transplantation. We assessed whether L_AUC could also be a useful factor for predicting severe infection in MS patients.

Methods

From October 2010 to January 2022, MS patients, diagnosed based on the 2017 McDonald criteria, were retrospectively reviewed. We extracted patients with infection requiring hospitalization (IRH) from medical records and matched with controls in a 1:2 ratio. Variables including clinical severity and laboratory data were compared between the infection group and controls. L_AUC was calculated along with the AUC of total white blood cells (W_AUC), neutrophils (N_AUC), lymphocytes (L_AUC), and monocytes (M_AUC). To correct for different times of blood examination and extract mean values of AUC per time point, we divided the AUC by follow-up duration. For example, in evaluating lymphocyte counts, we defined the ratio of [L_AUC] to [follow-up duration] as [L_AUC/t]. Multivariate regression analysis was conducted to extract predictive factors associated with IRH. Also, discriminative analysis was conducted using candidate variables from multivariate analysis.

Results

The total case-control sample included 177 patients of MS with IRH (n=59) and non-IRH (controls) (n=118). Adjusted odds ratios (OR) for the risk of serious infection in patients with MS with higher baseline expanded disability status scale (EDSS) (OR 1.340, 95% confidence interval [CI] 1.070-1.670, p = 0.010) and lower ratio of L_AUC/t to M_AUC/t (OR 0.766, 95%CI 0.591-0.993, p = 0.046) were significant. Notably, the kind of treatment, including glucocorticoids (GCs), disease-modifying drugs (DMDs) and other immunosuppressants agents, and dose of GCs were not significantly associated with serious infection after correlated with EDSS and ratio of L_AUC/t to M_AUC/t. In discriminative analysis, sensitivity was 88.1% (95%CI 76.5-94.7%) and specificity was 35.6% (95%CI 27.1-45.0%), using EDSS ≥ 6.0 or ratio of L_AUC/t to M_AUC/t ≤ 3.699, while sensitivity was 55.9% (95%CI 42.5-68.6%) and specificity was 83.9% (95%CI 75.7-89.8%), using both EDSS ≥ 6.0 and ratio of L_AUC/t to M_AUC/t ≤ 3.699.

Conclusion

Our study revealed the impact of the ratio L_AUC/t to M_AUC/t as a novel prognostic factor for IRH. Clinicians should pay more attention to laboratory data such as lymphocyte or monocyte counts itself, directly presenting individual immunodeficiency, rather than the kind of drug to prevent infection as a clinical manifestation.

First-in-human clinical trial of the NKT cell-stimulatory glycolipid OCH in multiple sclerosis

Background

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system that causes the damage to the myelin sheath as well as axonal degeneration. Individuals with MS appear to have changes in the numbers and functions of T-cell subsets, leading to an immunological imbalance accompanied by enhanced autoreactivity. In previous preclinical studies, (2 S,3 S,4R)-1-O-(α-D-Galactopyranosyl)-N-tetracosanoyl-2-amino-1,3,4-nonanetriol (OCH), a synthetic analog of α-galactosylceramide stimulatory for invariant NKT (iNKT) cells, has shown therapeutic or disease-preventive immunoregulatory effects in autoimmune disease models such as experimental autoimmune encephalomyelitis (EAE).

Objectives

This study is the first-in-human study of oral OCH to evaluate the pharmacokinetics and to examine the effects on immune cells as well as related gene expression profiles.

Methods

Fifteen healthy volunteers and 13 MS patients who met the study criteria were enrolled. They were divided into five cohorts and received oral administration of various doses of granulated powder of OCH (0.3-30 mg), once per week for 4 or 13 weeks. Plasma OCH concentrations were measured by high-performance liquid chromatography. Frequencies of lymphocyte subsets in peripheral blood were evaluated by flow cytometry, and microarray analysis was performed to determine OCH-induced changes in gene expression.

Results

Oral OCH was well tolerated, and its bioavailability was found to be sufficient. Six hours after a single dose of OCH, increased frequencies of Foxp3⁺ regulatory T-cells were observed in some cohorts of healthy subjects and MS patients. Furthermore, gene expression analysis demonstrated an upregulation of several immunoregulatory genes and downregulation of pro-inflammatory genes following OCH administration.

Conclusion

This study has demonstrated immunomodulatory effects of the iNKT cell-stimulatory drug OCH in human. Safety profiles together with the presumed anti-inflammatory effects of oral OCH encouraged us to conduct a phase II trial.

Long-term Efficacy of Satralizumab in AQP4-IgG-Seropositive Neuromyelitis Optica Spectrum Disorder From SAkuraSky and SAkuraStar

BACKGROUND AND OBJECTIVES

Satralizumab, an interleukin 6 receptor inhibitor, reduced the risk of protocol-defined relapse (PDR) vs placebo in 2 independent, double-blind studies in patients with neuromyelitis optica spectrum disorder (NMOSD). We assessed the long-term efficacy of satralizumab in patients with aquaporin-4-immunoglobulin G (IgG)-seropositive (AQP4-IgG+) NMOSD.

METHODS

Following the double-blind periods of SAkuraSky (satralizumab + baseline immunosuppressive treatment [IST]) and SAkuraStar (satralizumab monotherapy), patients could enter the open-label extension (OLE, satralizumab 120 mg Q4W ± IST). This analysis included all AQP4-IgG+ patients who received ≥1 dose of satralizumab in the double-blind and/or OLE periods, from patients' first dose to the data cutoff (February 22, 2021). PDR in the OLE period was determined by the investigator without external adjudication. We evaluated time to first investigator-reported PDR (iPDR), severe iPDR (≥2 point increase in the Expanded Disability Status Scale [EDSS] score), and sustained EDSS worsening (EDSS score increase of ≥2, ≥1, or ≥0.5 points for patients with baseline scores of 0, 1-5, or ≥5.5, respectively, confirmed ≥24 weeks post-initial worsening), plus the annualized iPDR rate (ARR).

RESULTS

Forty-six of 55 AQP4-IgG+ patients (84%) in SAkuraSky and 57/64 patients in SAkuraStar (89%) continued from the double-blind periods into the OLEs. In total, 111 AQP4-IgG+ patients received ≥1 dose of satralizumab in the double-blind and/or OLE periods and were included in these analyses (SAkuraSky: 49; SAkuraStar: 62). The median (range) duration of satralizumab exposure was 4.4 (0.1-7.0) years in SAkuraSky and 4.0 (0.1-6.0) years in SAkuraStar, with a combined 440.1 patient-years of treatment. Seventy-one of 111 patients (64%) received satralizumab for ≥192 weeks (3.7 years). At this time point, 71% (SAkuraSky) and 73% (SAkuraStar) of satralizumab-treated patients were free from iPDR, 91% (SAkuraSky) and 90% (SAkuraStar) were free from severe iPDR, and 90% (SAkuraSky) and 86% (SAkuraStar) had no sustained EDSS worsening. The overall adjusted ARR (95% CI) was 0.12 (0.08-0.18) in SAkuraSky and 0.08 (0.05-0.13) in SAkuraStar and remained stable over time.

DISCUSSION

These long-term results from the OLE periods of the SAkura studies demonstrate the continued efficacy of satralizumab over more than 3.5 years of treatment. High proportions of patients remained free from relapse, severe relapse, or worsening disease, with a consistently low ARR.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov registration numbers: NCT02028884 (SAkuraSky) and NCT02073279 (SAkuraStar).

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that satralizumab reduces the risk of relapse in patients with AQP4-IgG+ NMOSD beyond the first 96 weeks of treatment.

Neuropilin-1 (NRP1) expression distinguishes self-reactive helper T cells in systemic autoimmune disease

Pathogenic T helper cells (Th cells) that respond to self-antigen cannot be easily distinguished from beneficial Th cells. These cells can generate systemic autoimmune disease in response to widely expressed self-antigens. In this study, we have identified neuropilin-1 (NRP1) as a cell surface marker of self-reactive Th cells. NRP1⁺ Th cells, absent in non-regulatory T cell subsets in normal mice, appeared in models of systemic autoimmune disease and strongly correlated with disease symptoms. NRP1⁺ Th cells were greatly reduced in Nr4a2 cKO mice, which have reduced self-reactive responses but showed normal responses against exogenous antigens. Transfer of NRP1⁺ Th cells was sufficient to initiate or accelerate systemic autoimmune disease, and targeting NRP1-expressing Th cells therapeutically ameliorated SLE-like autoimmune symptoms in BXSB-Yaa mice. Peripheral NRP1⁺ Th cells were significantly increased in human SLE patients. Our data suggest that self-reactive Th cells can be phenotypically distinguished within the Th cell pool. These findings offer a novel approach to identify self-reactive Th cells and target them to treat systemic autoimmune disease.

Immune-mediated neurodegenerative trait provoked by multimodal derepression of long-interspersed nuclear element-1

Neurodegeneration is a process involving both cell autonomous and non-cell autonomous neuron loss, followed by a collapse of neural networks, but its pathogenesis is poorly understood. We have previously demonstrated that Eomes-positive helper T (Eomes + Th) cells recognizing LINE-1(L1)-derived prototypic antigen ORF1 mediate neurotoxicity associated with the neurodegenerative pathology of experimental autoimmune encephalomyelitis (EAE). Here, we show that Eomes + Th cells accumulate in the CNS of mouse models of authentic neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease (AD), and secrete the neurotoxic granzyme B after encounter with ORF1 antigen. Multimodal derepression of neuronal L1 transcription is observed in EAE and ALS/AD models during neurodegeneration in active and cell cycle-mediated manner, respectively. These data suggest that the adventitious concurrence of immune-mediated neurodegenerative traits by Eomes + Th cells and ectopic expression of L1-derived antigen(s) in the inflamed CNS may materialize a communal and previously unappreciated pathogenesis of neurodegeneration.

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Eomes + Th cells accumulate in the CNS with undergoing neurodegeneration in common

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Multimodal L1 derepression is emerged in neuron cells under neurodegeneration

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Eomes + Th cells recognize L1-ORF1 antigen to exert neurotoxicity via granzyme B

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Immune-mediated neurotoxicity may embody a novel pathogenesis of neurodegeneration

Silkworm recombinant bovine zona pellucida protein 4 (bZP4) as a potential female immunocontraceptive antigen; impaired sperm-oocyte interaction and ovarian dysfunction

Porcine zona pellucida proteins (ZPs) have been utilized as female immunocontraceptive antigens. The purpose of this study was to explore the potential use of silkworm recombinant bovine ZP4 as an alternative. When the protein was injected with monophosphoryl lipid A (MPL) - an immuno-stimulative agent - into two female goats, marked elevation of the anti-ZP4 titer was detected. Application of the purified specific IgG to a porcine in vitro fertilization system reduced the sperm penetration rate. In one goat, the cyclic profile of serum progesterone disappeared as the anti-ZP4 titer increased. Histological examination of the ovaries revealed degeneration of antral follicles with sparse infiltration of inflammatory cells in the theca, indicating that autoimmune oophoritis had been induced. Together, the present results suggest that recombinant ZP4 disturbs fertilization and exerts a pathogenic effect on follicle development in goats, thus indicating its potential as a female immunocontraceptive antigen.

Local administration of Neurokinin B in the arcuate nucleus accelerates the neural activity of the GnRH pulse generator in goats

Kisspeptin neurons in the arcuate nucleus (ARC), which co-express neurokinin B (NKB) and dynorphin A, are termed KNDy neurons. These neurons are candidates for the intrinsic gonadotropin-releasing hormone (GnRH) pulse generator. The central and peripheral administration of NKB or its receptor (NK3R) agonist evokes GnRH pulse generator activity and the subsequent pulsatile GnRH/luteinizing hormone (LH) secretion. However, the mechanism responsible for neural activation of the GnRH pulse generator in goats is unclear. We conducted electrophysiological and histochemical experiments to test the hypothesis that KNDy neurons receive NKB and that the signal is transmitted bilaterally to a population of KNDy neurons. Bilateral electrodes aimed at a cluster of KNDy neurons were inserted into the ovariectomized goat ARC. We observed the GnRH pulse generator activity, represented by characteristic increases in multiple-unit activity (MUA volleys). The unilateral administration of NKB or vehicle in the close vicinity of KNDy neurons under simultaneous MUA recording from both sides revealed that only NKB evoked MUA volley(s) immediately after administration. The timing of the MUA volley(s) evoked on the ipsilateral side was synchronized to that on the contralateral side. The double-labeled ISH for KISS1 and TACR3, which encode kisspeptin and NK3R, respectively, revealed that most KNDy neurons co-expressed TACR3. Therefore, NKB could directly stimulate KNDy neurons, following which the stimulatory signal is immediately transmitted to the entire population of KNDy neurons via connection with their fibers. This mechanism helps synchronize burst activity among KNDy neurons, thereby generating neural signals that govern pulsatile GnRH secretion.

Intrathymic Plasmablasts Are Affected in Patients With Myasthenia Gravis With Active Disease

Background and Objectives

To investigate intrathymic B lymphopoiesis in patients with myasthenia gravis (MG) and explore thymus pathology associated with clinical impact.

Methods

Thymic lymphocytes from 15 young patients without MG, 22 adult patients without MG, 14 patients with MG without thymoma, and 11 patients with MG with thymoma were subjected to flow cytometry analysis of T follicular helper (Tfh), naive B, memory B, plasmablasts, CD19⁺B220^high thymic B cells, B-cell activating factor receptor, and C-X-C chemokine receptor 5 (CXCR5). Peripheral blood mononuclear cells of 16 healthy subjects and 21 untreated patients with MG were also analyzed. Immunologic values were compared, and correlations between relevant values and clinical parameters were evaluated.

Results

The frequencies of circulating and intrathymic plasmablasts were significantly higher in patients with MG than controls. On the other hand, the frequency of CD19⁺B220^high thymic B cells was not increased in MG thymus. We observed a significant increase in CXCR5 expression on plasmablasts in MG thymus and an increased frequency of intrathymic plasmablasts that was correlated with preoperative disease activity. The frequency of intrathymic Tfh cells was significantly lower in patients who received immunosuppressive (IS) therapy than those without IS therapy. However, there was no significant difference in the frequency of intrathymic plasmablasts irrespective of IS therapy.

Discussion

Our findings confirmed a correlation between increased frequency of intrathymic plasmablasts and disease activity before thymectomy. We postulate that activated intrathymic plasmablasts endow pathogenic capacity in MG.

Extracellular Vesicles as Pro- and Anti-inflammatory Mediators, Biomarkers and Potential Therapeutic Agents in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system (CNS) characterized by multiple demyelinating lesions in the spinal cord and brain. Neuronal disruption caused by myelin loss or demyelination, which may accompany axonal changes, leads to multiple neurological symptoms. They may transiently appear for weeks during periods of disease worsening (relapse) in relapsing-remitting form of MS (RRMS). Although a number of genetic, metabolic and environmental factors influencing the development of MS have been identified, the precise mechanisms involved in the CNS tissue damage in MS are still poorly understood. Recent studies have revealed a significant role of circulating extracellular vesicles (EVs) in many diseases. EVs are known to serve as a cellular communication tool between two cell types either in close proximity or in different parts of the body. During the recent development in understanding of the pathogenesis of MS, studies have revealed the possible role of EVs in MS. Furthermore, circulating EVs can be used as a biomarker for monitoring disease progression and activity of MS, and they can also be therapeutic reagents or targets of therapy. In this review we overview and discuss in detail about generation of EVs and their diversified roles in MS.

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

[Multiple Sclerosis and Gut Microbiome: Current Research and Perspective]

Multiple sclerosis (MS) is a neurological disease in which alterations of the gut microbiota can be confirmed by metagenomic analysis. In addition to the 16S rRNA analysis, whole metagenomic analysis, as well as, metabolomic analysis, has been applied in this field, which convincingly proved that the reduction of short chain fatty acids characterizes the intestinal environment of patients with MS. Further research is needed to elucidate the mechanisms responsible for the alterations of the gut microbiome in patients with MS. Characterization of the virome may shed light on.

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 microbiome research in multiple sclerosis

Recent studies identified specific gut microbial species linked to various human diseases, and gut-brain axis is currently attracting much attention in the field of microbiome science clinically and biologically. Research on multiple sclerosis (MS) and its mouse model, experimental autoimmune encephalomyelitis is one of the most active research subjects. Notably, recent achievements established the bidirectional causality between MS and gut microbiome. The reduction of gut microbiome-derived short chain fatty acids and the enrichment of gut-associated oxidative stress appear to be promoting for neurodegenerative processes. Also, researchers are trying to elucidate the mechanisms by which the microbiome regulates the onset and progression of MS. The new findings achieved by the analysis of the causal relationship between MS and the gut microbiome will provide a new therapeutic strategy for MS. These results will contribute to our understanding of the cause, prevention, and treatment of MS, and will lead to a complete cure for this disease in the future. In MS, for which no curative treatment has yet to be established, the unmet needs may be overcome through the analysis of gut microbiome.

Neurokinin 3 receptor-selective agonist, senktide, decreases core temperature in Japanese Black cattle

Heat stress disrupts reproductive function in cattle. In summer, high ambient temperature and humidity elevate core body temperature, which is considered to be detrimental to reproductive abilities in cattle. Neurokinin B (NKB) is a factor that generates pulsatile GnRH and subsequent LH secretion in mammals. Recent studies have reported that NKB-neurokinin 3 receptor (NK3R) signaling is associated with heat-defense responses in rodents. The present study aimed to clarify the role of NKB-NK3R signaling in thermoregulation in cattle. We examined the effects of an NK3R-selective agonist, senktide, on vaginal temperature as an indicator of core body temperature in winter and summer. In both seasons, continuous infusion of senktide for 4 h immediately decreased vaginal temperature, and the mean temperature change in the senktide-treated group was significantly lower than that of both vehicle- and GnRH-treated groups. Administration of GnRH induced LH elevation, but there was no significant difference in vaginal temperature change between GnRH- and vehicle-treated groups. Moreover, we investigated the effects of senktide on ovarian temperature. Senktide treatment seemed to suppress the increase in ovarian temperature from 2 h after the beginning of administration, although the difference between groups was not statistically significant. Taken together, these results suggest that senktide infusion caused a decline in the vaginal temperature of cattle, in both winter and summer seasons, and this effect was not due to the gonadotropin-releasing action of senktide. These findings provide new therapeutic options for senktide to support both heat-defense responses and GnRH/LH pulse generation.

Satralizumab: An Interleukin-6 Receptor-blocking Therapy for Neuromyelitis Optica Spectrum Disorder

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Interleukin-6 in neuromyelitis optica spectrum disorder pathophysiology

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disorder that preferentially affects the spinal cord and optic nerve. Most patients with NMOSD experience severe relapses that lead to permanent neurologic disability; therefore, limiting frequency and severity of these attacks is the primary goal of disease management. Currently, patients are treated with immunosuppressants. Interleukin-6 (IL-6) is a pleiotropic cytokine that is significantly elevated in the serum and the CSF of patients with NMOSD. IL-6 may have multiple roles in NMOSD pathophysiology by promoting plasmablast survival, stimulating the production of antibodies against aquaporin-4, disrupting blood-brain barrier integrity and functionality, and enhancing proinflammatory T-lymphocyte differentiation and activation. Case series have shown decreased relapse rates following IL-6 receptor (IL-6R) blockade in patients with NMOSD, and 2 recent phase 3 randomized controlled trials confirmed that IL-6R inhibition reduces the risk of relapses in NMOSD. As such, inhibition of IL-6 activity represents a promising emerging therapy for the management of NMOSD manifestations. In this review, we summarize the role of IL-6 in the context of NMOSD.

Altered Structural Brain Networks Related to Adrenergic/Muscarinic Receptor Autoantibodies in Chronic Fatigue Syndrome

BACKGROUND AND PURPOSE

Recent studies suggest that the autoantibodies against adrenergic/muscarinic receptors might be one of the causes and potential markers of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The purpose of this study was to investigate the structural network changes related to autoantibody titers against adrenergic/muscarinic receptors in ME/CFS by performing a single-subject gray matter similarity-based structural network analysis.

METHODS

We prospectively examined 89 consecutive right-handed ME/CFS patients who underwent both brain MRI including 3D T1-wighted images and a blood analysis of autoantibodies titers against β1 adrenergic receptor (β1 AdR-Ab), β2 AdR-Ab, M3 acetylcholine receptor (M3 AchR-Ab), and M4 AchR-Ab. Single-subject gray matter similarity-based structural networks were extracted from segmented gray matter images for each patient. We calculated local network properties (betweenness centrality, clustering coefficient, and characteristic path length) and global network properties (normalized path length λ, normalized clustering coefficient γ, and small-world network value δ). We investigated the correlations between the autoantibody titers and regional gray matter/white matter volumes, the local network properties, and the global network properties.

RESULTS

Betweenness centrality showed a significant positive correlation with β1-AdR-Ab in the right dorsolateral prefrontal cortex. The characteristic path length showed a significant negative correlation with β2-AdR-Ab in the right precentral gyrus. There were no significant correlations between the antibody titers and the regional gray matter/white matter volumes, and the global network properties.

CONCLUSIONS

Our findings suggest that β1 AdR-Ab and β2 AdR-Ab are potential markers of ME/CFS.

Intravaginal administration of progesterone using a new technique for sustained drug release in goats

The objective of the present study was to develop and evaluate a sustained release vaginal progesterone (P₄) capsule containing a mixture of mucoadhesive polymer and silicone fluid. Goats were administered a gelatin capsule containing 0.4 g of P₄ mixed in silicone fluid and either a hydroxypropylmethylcellulose (HM) or polyaclil starch (PA) base. The mean plasma P₄ concentrations at 2 and 12 h after administration were significantly higher in goats treated with PA capsules than in those with HM capsules. The plasma P₄ concentrations in goats treated with HM capsules increased and remained above 1.0 ng/ml for 96 h after administration, whereas the plasma P₄ concentrations in goats treated with PA capsules remained above 1.0 ng/ml for only 24 h after administration. In the next experiment, an HM capsule was attached to a silicone device and inserted in the vagina for 10 days. The plasma P₄ concentration remained similar to that of the natural luteal phase for 9 days. These results suggest that a mixture of mucoadhesive polymer and silicone fluid has the potential to be applied clinically as a sustained release base for estrus synchronization or hormonal therapy.

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.

Trial of Satralizumab in Neuromyelitis Optica Spectrum Disorder

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system and is associated with autoantibodies to anti-aquaporin-4 (AQP4-IgG) in approximately two thirds of patients. Interleukin-6 is involved in the pathogenesis of the disorder. Satralizumab is a humanized monoclonal antibody targeting the interleukin-6 receptor. The efficacy of satralizumab added to immunosuppressant treatment in patients with NMOSD is unclear.

METHODS

In a phase 3, randomized, double-blind, placebo-controlled trial, we randomly assigned, in a 1:1 ratio, patients with NMOSD who were seropositive or seronegative for AQP4-IgG to receive either satralizumab, at a dose of 120 mg, or placebo, administered subcutaneously at weeks 0, 2, and 4 and every 4 weeks thereafter, added to stable immunosuppressant treatment. The primary end point was the first protocol-defined relapse in a time-to-event analysis. Key secondary end points were the change from baseline to week 24 in the visual-analogue scale (VAS) pain score (range, 0 to 100, with higher scores indicating more pain) and the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) score (range, 0 to 52, with lower scores indicating more fatigue). Safety was also assessed.

RESULTS

A total of 83 patients were enrolled, with 41 assigned to the satralizumab group and 42 to the placebo group. The median treatment duration with satralizumab in the double-blind period was 107.4 weeks. Relapse occurred in 8 patients (20%) receiving satralizumab and in 18 (43%) receiving placebo (hazard ratio, 0.38; 95% confidence interval [CI], 0.16 to 0.88). Multiple imputation for censored data resulted in hazard ratios ranging from 0.34 to 0.44 (with corresponding P values of 0.01 to 0.04). Among 55 AQP4-IgG-seropositive patients, relapse occurred in 11% of those in the satralizumab group and in 43% of those in the placebo group (hazard ratio, 0.21; 95% CI, 0.06 to 0.75); among 28 AQP4-IgG-seronegative patients, relapse occurred in 36% and 43%, respectively (hazard ratio, 0.66; 95% CI, 0.20 to 2.24). The between-group difference in the change in the mean VAS pain score was 4.08 (95% CI, -8.44 to 16.61); the between-group difference in the change in the mean FACIT-F score was -3.10 (95% CI, -8.38 to 2.18). The rates of serious adverse events and infections did not differ between groups.

CONCLUSIONS

Among patients with NMOSD, satralizumab added to immunosuppressant treatment led to a lower risk of relapse than placebo but did not differ from placebo in its effect on pain or fatigue. (Funded by Chugai Pharmaceutical; ClinicalTrials.gov number, NCT02028884.).

Plasmablasts and neuroimmunological disorders

Neuroimmunological disorders are diseases of the nervous system, wherein the immune system contributes to tissue injury and repair. Autoantibodies are useful biomarkers for the diagnosis of neuroimmunological disorders and evaluating disease activity. Emerging evidence indicates that several autoantibodies are associated with neuroimmunological diseases. While the differential diagnostic process based on the positivity of autoantibodies has been established, the mechanisms underlying the production of these autoantibodies still need to be investigated. Autoantibodies are not necessarily pathogenic, and some are involved in immune regulation. Autoantibody-producing plasmablasts are involved in both pathogenicity and immune regulation of diseases. Thus, comparisons between these pathogenic and regulatory plasmablasts may give us clues understanding the machinery of autoantibody-related neuroimmunological diseases. Moreover, elucidating these mechanisms may allow the development of new immune-modulatory therapies to facilitate regulatory B cell function in neuroimmunological diseases. To this end, herein the roles of plasmablasts in neuroimmunological disorders are discussed.

Peripheral administration of κ-opioid receptor antagonist stimulates gonadotropin-releasing hormone pulse generator activity in ovariectomized, estrogen-treated female goats

Pulsatile gonadotropin-releasing hormone (GnRH) secretion is indispensable for reproduction in mammals. Kisspeptin neurons in the hypothalamic arcuate nucleus (ARC), referred to as KNDy neurons because of the coexpression of neurokinin B and dynorphin A, are considered as components of the GnRH pulse generator that produces rhythmic GnRH secretion. The present study aimed to investigate if peripheral administration of PF-4455242, a κ-opioid receptor (KOR, a dynorphin A receptor) antagonist, facilitates pulsatile luteinizing hormone (LH) secretion and GnRH pulse generator activity in estrogen-treated ovariectomized Shiba goats to determine the possibility of using KOR antagonists to artificially control ovarian activities. PF-4455242 was intravenously infused for 4 h (1 or 10 μmol/kg body weight/4 h) or as a single subcutaneous injection (1 or 10 μmol/kg body weight). In a separate experiment, the same KOR antagonist (10 μmol/kg body weight/4 h) was intravenously infused during the recording of multiple unit activity (MUA) in the ARC that reflects the activity of the GnRH pulse generator to test the effects of KOR antagonist administration on GnRH pulse generator activity. Intravenous infusion and single subcutaneous injection of the KOR antagonist significantly increased the frequency of LH pulses compared with controls. Intravenous infusion of KOR antagonist also significantly increased the frequency of episodic bursts in the MUA. The present study demonstrates that peripherally administered KOR antagonist stimulates pulsatile LH secretion by acting on the GnRH pulse generator, and peripheral administration of PF-4455242 can be used to facilitate pulsatile LH secretion, which in turn facilitates ovarian activities in farm animals.

Multiple sclerosis: Possibility of a gut environment-induced disease

Multiple sclerosis is a putative autoimmune disease of the central nervous system, a representative disease of 'neuroimmunology.' We now understand that gut microbiota constitutes an integral part of our body and play critical roles in various neurological diseases with which no intestinal pathology was previously associated. In fact, several reports from Japan, North America, and Europe confirmed dysbiosis of the gut microbiome in MS patients. Given the increase in the prevalence of MS worldwide, especially in Japan, some previously unknown causal environmental factors needed to be identified to inhibit the development of MS in future generations. In this review, we will introduce recent key topics related to MS pathogenesis and immune cells linking gut and brain, and then summarize studies on gut microbiome in MS and its mouse model. Lastly, we will discuss the potential role of diet in the development of MS and propose a hypothesis that could explain the dramatic increase in the number of patients suffering with MS in Japan in the past few decades.