Pathogenesis Of Multiple Sclerosis Research Articles

The Immunomodulatory Potential of Short-Chain Fatty Acids in Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative central nervous system (CNS) disorder, characterized by focal inflammation, demyelination, irreversible axonal loss and neurodegeneration. The proposed mechanism involves auto-reactive T lymphocytes crossing the blood-brain barrier (BBB), contributing to inflammation and demyelination. Pro-inflammatory Th1 and Th17 lymphocytes are pivotal in MS pathogenesis, highlighting an imbalanced interaction with regulatory T cells. Dysbiosis in the gut microbiota, characterized by microbial imbalance is implicated in systemic inflammation, yet its exact role in MS remains elusive. Short-chain fatty acids (SCFAs), including valerate, butyrate, propionate, and acetate, produced through dietary fiber fermentation by the gut microbiota, modulate inflammation and immune responses. Particularly, butyrate and propionate exhibit pronounced anti-inflammatory effects in both the gut and CNS. These SCFAs influence regulatory T lymphocyte expression and BBB permeability. This review discusses the potential therapeutic implications of SCFA in MS, highlighting their ability to modulate the gut-brain axis and restore immune balance.

Complete Blood Count in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease that affects the central nervous system in primarily young adults. Although the exact etiology of MS is unknown, autoimmune mechanisms are thought to play a crucial role, especially with CD4+ T cells involved in the immune response. Inflammatory reactions involving T cells and macrophages are commonly observed in MS lesions. B lymphocytes, plasma cells, and antibodies also contribute to MS pathogenesis. Neutrophils, lymphocytes, monocytes, and platelets, key immune system components, play roles in inflammatory processes, but their association with MS prognosis remains inconclusive. Due to its heterogeneous nature, clinical manifestations of MS vary depending on the location of the affected central nervous system. While several potential biomarkers have been identified for MS diagnosis and monitoring, none have been universally accepted. Studies have examined complete blood count parameters in MS patients, including erythrocyte, platelet, and leukocyte populations. Changes in these parameters have been observed in MS patients compared to healthy controls and may be related to disease prognosis. For example, increased erythrocyte fragility and altered hemoglobin levels have been reported in MS patients. Leukocyte counts and ratios, such as the neutrophil/lymphocyte ratio, have shown associations with disease severity. Platelet activation and interaction with immune cells have also been implicated in MS pathophysiology. Nevertheless, further research is needed to fully understand the role of complete blood count parameters in MS. Identifying reliable biomarkers for early diagnosis and prognosis prediction would greatly enhance MS management. Moreover, these benefits could lead to substantial improvements in achieving complete recovery of patients, surpassing the focus on current symptomatic treatments.

Role of autoreactive Tc17 cells in the pathogenesis of experimental autoimmune encephalomyelitis

AbstractBackgroundThe pathogenesis of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE—an animal model of MS) is primarily mediated by T cells. However, recent studies have only focused on interleukin (IL)‐17‐secreting CD4+ T‐helper cells, also known as Th17 cells. This study aimed to compare Th17 cells and IL‐17‐secreting CD8+ T‐cytotoxic cells (Tc17) in the context of MS/EAE.MethodsFemale C57BL/6 mice were immunized with myelin oligodendrocyte glycoprotein peptides 35–55 (MOG35–55), pertussis toxin, and complete Freund's adjuvant to establish the EAE animal model. T cells were isolated from the spleen (12–14 days postimmunization). CD4+ and CD8+ T cells were purified using isolation kit and then differentiated into Th17 and Tc17, respectively, using MOG35–55 and IL‐23. The secretion levels of interferon‐γ (IFN‐γ) and IL‐17 were measured via enzyme‐linked immunosorbent assay using cultured CD4+ and CD8+ T cell supernatants. The pathogenicity of Tc17 and Th17 cells was assessed through adoptive transfer (tEAE), with the clinical course assessed using an EAE score (0–5). Hematoxylin and eosin as well as Luxol fast blue staining were used to examine the spinal cord. Purified CD8+ CD3+ and CD4+ CD3+ cells differentiated into Tc17 and Th17 cells, respectively, were stimulated with MOG35–55 peptide for proliferation assays.ResultsThe results showed that Tc17 cells (15,951 ± 1985 vs. 55,709 ± 4196 cpm; p < 0.050) exhibited a weaker response to highest dose (20 μg/mL) MOG35–55 than Th17 cells. However, this response was not dependent on Th17 cells. After the 48 h stimulation, at the highest dose (20 μg/mL) of MOG35–55. Tc17 cells secreted lower levels of IFN‐γ (280.00 ± 15.00 vs. 556.67 ± 15.28 pg/mL, p < 0.050) and IL‐17 (102.67 ± 5.86 pg/mL vs. 288.33 ± 12.58 pg/mL; p < 0.050) than Th17 cells. Similar patterns were observed for IFN‐γ secretion at 96 and 144 h. Furthermore, Tc17 cell‐induced tEAE mice exhibited similar EAE scores to Th17 cell‐induced tEAE mice and also showed similar inflammation and demyelination.ConclusionThe degree of pathogenicity of Tc17 cells in EAE is lower than that of Th17 cells. Future investigation on different immune cells and EAE models is warranted to determine the mechanisms underlying MS.

Ocrelizumab B cell depletion has no effect on HERV RNA expression in PBMC in MS patients

BackgroundEpstein barr virus (EBV) infection of B cells is now understood to be one of the triggering events for the development of Multiple Sclerosis (MS), a progressive immune-mediated disease of the central nervous system. EBV infection is also linked to expression of human endogenous retroviruses (HERVs) of the HERV-W group, a further risk factor for the development of MS. Ocrelizumab is a high-potency disease-modifying treatment (DMT) for MS, which depletes B cells by targeting CD20. ObjectivesWe studied the effects of ocrelizumab on gene expression in peripheral blood mononuclear cells (PBMC) from paired samples from 20 patients taken prior to and 6 months after beginning ocrelizumab therapy. We hypothesised that EBV and HERV-W loads would be lower in post-treatment samples. MethodsSamples were collected in Paxgene tubes, subject to RNA extraction and Illumina paired end short read mRNA sequencing with mapping of sequence reads to the human genome using Salmon and differential gene expression compared with DeSeq2. Mapping was also performed separately to the HERV-D database of HERV sequences and the EBV reference sequence. ResultsPatient samples were more strongly clustered by individual rather than disease type (relapsing/remitting or primary progressive), treatment (pre and post), age, or sex. Fourteen genes, all clearly linked to B cell function were significantly down regulated in the post treatment samples. Interestingly only one pre-treatment sample had detectable EBV RNA and there were no significant differences in HERV expression (of any group) between pre- and post-treatment samples. ConclusionsWhile EBV and HERV expression are clearly linked to triggering MS pathogenesis, it does not appear that high level expression of these viruses is a part of the ongoing disease process or that changes in virus load are associated with ocrelizumab treatment.

Micro-diffusely abnormal white matter: An early multiple sclerosis lesion phase with intensified myelin blistering.

Multiple sclerosis (MS) is a chronic central nervous system disease whose white matter lesion origin remains debated. Recently, we reported subtle changes in the MS normal appearing white matter (NAWM), presenting with an increase in myelin blisters and myelin protein citrullination, which may recapitulate some of the prodromal degenerative processes involved in MS pathogenesis. Here, to clarify the relevance of these changes for subsequent MS myelin degeneration we explored their prevalence in WM regions characterized by subtly reduced myelination (dubbed as micro-diffusely abnormal white matter, mDAWM). We used an in-depth (immuno)histochemistry approach in 27 MS donors with histological presence of mDAWM and 5 controls. An antibody panel against degenerative markers was combined and the presence of myelin/axonal aberrations was analyzed and compared with the NAWM from the same cases/slices/regions. mDAWM-defined areas exhibit ill-defined borders, no signs of Wallerian degeneration, and they associate with visible veins. Remarkably, such areas present with augmented myelin blister frequency, enhanced prevalence of polar myelin phospholipids, citrullination, and degradation of myelin basic protein (MBP) when compared with the NAWM. Furthermore, enhanced reactivity of microglia/macrophages against citrullinated MBP was also observed in this tissue. We report a new histologically defined early phase in MS lesion formation, namely mDAWM, which lacks signs of Wallerian pathology. These results support the prelesional nature of the mDAWM. We conceptualize that evolution to pathologically evident lesions comprises the previously documented imbalance of axo-myelinic units (myelin blistering) leading to their degeneration and immune system activation by released myelin components.

TPN10475 Constrains Effector T Lymphocytes Activation and Attenuates Experimental Autoimmune Encephalomyelitis Pathogenesis by Facilitating TGF-β Signal Transduction.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) mediated by immune cells, in which auto-reactive CD4+ T cells have been implicated as a major driver in the pathogenesis of the disease. In this study, we aimed to investigate whether the artemisinin derivative TPN10475 could alleviate experimental autoimmune encephalomyelitis (EAE), a commonly used animal model of MS and its possible mechanisms. TPN10475 effectively resisted the reduction of TGF-β signal transduction induced by TCR stimulation, suppressed the activation and function of effector CD4+ T cells in vitro, and restricted the differentiation of pathogenic Th1 and Th17 cells. It was also found to negatively regulate the inflammatory response in EAE by reducing the peripheral activation drive of auto-reactive helper T lymphocytes, inhibiting the migration of inflammatory cells into the CNS to attenuate EAE. The above results suggested that the upregulation of TGF-β signal transduction may provide new ideas for the study of MS pathogenesis and have positive implications for the development of drugs for the treatment of autoimmune diseases.

AMP-activated protein kinase as a mediator of mitochondrial dysfunction of multiple sclerosis in animal models: A systematic review.

Multiple sclerosis (MS) is a chronic central nervous system (CNS) disorder characterized by demyelination, neuronal damage, and oligodendrocyte depletion. Reliable biomarkers are essential for early diagnosis and disease management. Emerging research highlights the role of mitochondrial dysfunction and oxidative stress in CNS disorders, including MS, in which mitochondria are central to the degenerative process. Adenosine monophosphate-activated protein kinase (AMPK) regulates the mitochondrial energy balance and initiates responses in neurodegenerative conditions. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aimed to comprehensively assess the literature on AMPK pathways, mitochondrial dysfunction, and in vivo studies using MS animal models. The search strategy involved the use of AMPK syntaxes, MS syntaxes, and animal model syntaxes. The PubMed, Scopus, Web of Science, and Google Scholar databases were systematically searched onAugust 26, 2023 without publication year restrictions. The review identified and analyzed relevant papers to provide a comprehensive overview of the current state of related research. Eight studies utilizing various interventions and methodological approaches were included. Risk of bias assessment revealed some areas of low risk but lacked explicit reporting in others. These studies collectively revealed a complex relationship between AMPK, mitochondrial dysfunction, and MS pathogenesis, with both cuprizone and experimental autoimmune encephalomyelitis models demonstrating associations between AMPK and mitochondrial disorders, including oxidative stress and impaired expression of mitochondrial genes. These studies illuminate the multifaceted role of AMPK in MS animal models, involving energy metabolism, inflammatory processes, oxidative stress, and gene regulation leading to mitochondrial dysfunction. However, unanswered questions about its mechanisms and clinical applications underscore the need for further research to fully harness its potential in addressing MS-related mitochondrial dysfunction.

Guardians of Immunity: Toll-Like Receptor Signalling in the Onset and Progression of Multiple Sclerosis, Sketching an Immunopathological Scheme

Background: Multiple Sclerosis (MS) is a chronic autoimmune disorder of the central nervous system, characterized by inflammation, demyelination, and neurodegeneration. The role of toll-like receptors (TLRs) in MS pathogenesis, specifically through MYD88-dependent and -independent pathways, has become a focal point of research. Understanding these pathways offers insights into the mechanisms driving MS and potential therapeutic targets. Objective: This review aims to synthesize current knowledge on the role of TLR signaling in the onset and progression of MS, focusing on the dysregulation of MYD88-dependent and -independent pathways and their implications for disease pathogenesis and therapy. Methods: A systematic search of PubMed, Scopus, Web of Science, and Google Scholar databases was conducted to identify studies related to TLR signaling in MS. Keywords related to "toll-like receptors," "multiple sclerosis," "MYD88-dependent pathway," "MYD88-independent pathway," and "immune response" were used. The evidence synthesis was qualitative, integrating findings from both human and animal studies. Results: The review highlights the central role of NF-kB in mediating the effects of TLR signaling on the inflammatory cascade in MS. Dysregulation in TLR signaling pathways can lead to increased expression of pro-inflammatory cytokines and compromise the blood-brain barrier, exacerbating MS pathogenesis. The evidence points towards the dual role of TLR pathways in promoting inflammatory responses and potentially offering protective mechanisms against the disease. Conclusion: TLR signaling pathways play a crucial role in the immunopathology of MS, with both MYD88-dependent and -independent pathways contributing to disease progression. Targeting these pathways presents a promising therapeutic strategy, emphasizing the need for further research to develop effective treatments.

Inhibition of CD40L with Frexalimab in Multiple Sclerosis

BackgroundThe CD40–CD40L costimulatory pathway regulates adaptive and innate immune responses and has been implicated in the pathogenesis of multiple sclerosis. Frexalimab is a second-generation anti-CD40L monoclonal antibody being evaluated for the treatment of multiple sclerosis.MethodsIn this phase 2, double-blind, randomized trial, we assigned, in a 4:4:1:1 ratio, participants with relapsing multiple sclerosis to receive 1200 mg of frexalimab administered intravenously every 4 weeks (with an 1800-mg loading dose), 300 mg of frexalimab administered subcutaneously every 2 weeks (with a 600-mg loading dose), or the matching placebos for each active treatment. The primary end point was the number of new gadolinium-enhancing T1-weighted lesions seen on magnetic resonance imaging at week 12 relative to week 8. Secondary end points included the number of new or enlarging T2-weighted lesions at week 12 relative to week 8, the total number of gadolinium-enhancing T1-weighted lesions at week 12, and safety. After 12 weeks, all the participants could receive open-label frexalimab.ResultsOf 166 participants screened, 129 were assigned to a trial group; 125 participants (97%) completed the 12-week double-blind period. The mean age of the participants was 36.6 years, 66% were women, and 30% had gadolinium-enhancing lesions at baseline. At week 12, the adjusted mean number of new gadolinium-enhancing T1-weighted lesions was 0.2 (95% confidence interval [CI], 0.1 to 0.4) in the group that received 1200 mg of frexalimab intravenously and 0.3 (95% CI, 0.1 to 0.6) in the group that received 300 mg of frexalimab subcutaneously, as compared with 1.4 (95% CI, 0.6 to 3.0) in the pooled placebo group. The rate ratios as compared with placebo were 0.11 (95% CI, 0.03 to 0.38) in the 1200-mg group and 0.21 (95% CI, 0.08 to 0.56) in the 300-mg group. Results for the secondary imaging end points were generally in the same direction as those for the primary analysis. The most common adverse events were coronavirus disease 2019 and headaches.ConclusionsIn a phase 2 trial involving participants with multiple sclerosis, inhibition of CD40L with frexalimab had an effect that generally favored a greater reduction in the number of new gadolinium-enhancing T1-weighted lesions at week 12 as compared with placebo. Larger and longer trials are needed to determine the long-term efficacy and safety of frexalimab in persons with multiple sclerosis. (Funded by Sanofi; ClinicalTrials.gov number, NCT04879628.)

Complete Freund's adjuvant as a confounding factor in multiple sclerosis research.

Complete Freund's adjuvant (CFA) is used as a standard adjuvant for the induction of experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model in multiple sclerosis studies. Still, CFA induces glial activation and neuroinflammation on its own and provokes pain. In addition, as CFA contains Mycobacteria, an immune response against bacterial antigens is induced in parallel to the response against central nervous system antigens. Thus, CFA can be considered as a confounding factor in multiple sclerosis-related studies performed on EAE. Here, we discuss the effects of CFA in EAE in detail and present EAE variants induced in experimental animals without the use of CFA. We put forward CFA-free EAE variants as valuable tools for studying multiple sclerosis pathogenesis and therapeutic approaches.

CD11c+ B cells in relapsing-remitting multiple sclerosis and effects of anti-CD20 therapy.

B cells are important in the pathogenesis of multiple sclerosis. It is yet unknown which subsets may be involved, but atypical B cells have been proposed as mediators of autoimmunity. In this study, we investigated differences in B-cell subsets between controls and patients with untreated and anti-CD20-treated multiple sclerosis. We recruited 155 participants for an exploratory cohort comprising peripheral blood and cerebrospinal fluid, and a validation cohort comprising peripheral blood. Flow cytometry was used to characterize B-cell phenotypes and effector functions of CD11c+ atypical B cells. There were no differences in circulating B cells between controls and untreated multiple sclerosis. As expected, anti-CD20-treated patients had a markedly lower B-cell count. Of B cells remaining after treatment, we observed higher proportions of CD11c+ B cells and plasmablasts. CD11c+ B cells were expanded in cerebrospinal fluid compared to peripheral blood in controls and untreated multiple sclerosis. Surprisingly, the proportion of CD11c+ cerebrospinal fluid B cells was higher in controls and after anti-CD20 therapy than in untreated multiple sclerosis. Apart from the presence of plasmablasts, the cerebrospinal fluid B-cell composition after anti-CD20 therapy resembled that of controls. CD11c+ B cells demonstrated a high potential for both proinflammatory and regulatory cytokine production. The study demonstrates that CD11c+ B cells and plasmablasts are less efficiently depleted by anti-CD20 therapy, and that CD11c+ B cells comprise a phenotypically and functionally distinct, albeit heterogenous, B-cell subset with the capacity of exerting both proinflammatory and regulatory functions.

T cells implicate Epstein-Barr virus in multiple sclerosis pathogenesis.

T cells implicate Epstein-Barr virus in multiple sclerosis pathogenesis.

NLRP3 exacerbates EAE severity through ROS-dependent NET formation in the mouse brain

BackgroundNeutrophil extracellular trap (NET) has been implicated in the pathology of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). However, the specific contributions of NLRP3, a NET-associated molecule, to EAE pathogenesis and its regulatory role in NET formation remain unknown.MethodsTo investigate the detrimental effect of NETs supported by NLRP3 in MS pathogenesis, we induced EAE in WT and NLRP3 KO mice and monitored the disease severity. At the peak of the disease, NET formation was assessed by flow cytometry, immunoblotting, and immunofluorescence staining. To further identify the propensity of infiltrated neutrophils, NET-related chemokine receptors, degranulation, ROS production, and PAD4 expression levels were evaluated by flow cytometry. In some experiments, mice were injected with DNase-1 to eliminate the formed NETs.ResultsOur data revealed that neutrophils significantly infiltrate the brain and spinal cord and form NETs during EAE pathogenesis. NLRP3 significantly elevates NET formation, primarily in the brain. NLRP3 also modulated the phenotypes of brain-infiltrated and circulating neutrophils, augmenting CXCR2 and CXCR4 expression, thereby potentially enhancing NET formation. NLRP3 facilitates NET formation in a ROS-dependent and PAD4-independent manner in brain-infiltrated neutrophils. Finally, NLRP3-supported NET formation exacerbates disease severity, triggering Th1 and Th17 cells recruitment.ConclusionsCollectively, our findings suggest that NLRP3-supported NETs may be an etiological factor in EAE pathogenesis, primarily in the brain. This study provides evidence that targeting NLRP3 could be a potential therapeutic strategy for MS, specifically by attenuating NET formation.

Folate receptor alpha autoantibodies in the serum of patients with relapsing–remitting multiple sclerosis (RRMS)

Multiple sclerosis (MS) is a potentially progressive, autoimmune neurologic disorder of the central nervous system (CNS), resulting from an autoimmune attack on central nervous system white matter. Folate deficiencies are linked to DNA instability and breakdown of phospholipid membranes and thus might affect myelin integrity. Folic acid exerts its effects through its receptors (FRs). Folate receptor alpha autoantibodies (FRAA) can block folate transport to the brain. Due to important role of folate in the pathogenesis of MS, in this project we aimed to study FRAA serum levels in patients with relapsing remitting multiple sclerosis (RRMS). Fifty-four patients with RRMS and 58 healthy individuals were enrolled in this study. Serum samples were collected from all participants and folate receptor alpha autoantibody (FRAA) serum concentration was measured by Enzyme-linked immunosorbent assay (ELISA). The results showed that FRAA serum levels in patients with RRMS is 67.20±19.79ng/ml as compared to controls which was 37.32±13.26ng/ml. Significant increase in folate receptor autoantibody serum concentration was seen in patients with RRMS when compared to control group (P=0.007). The results showed that a high concentration of folate receptor autoantibody is associated with RRMS. We have also found that 85.18% (46/54) of patients with RRMS were positive for serum FRAA, whereas the prevalence in controls was only 46.55% (27/58). It is concluded that serum FRAA are more prevalent in RRMS patients than controls. The findings also suggest that FRAA might be involved in the pathophysiology of RRMS.

Electrochemical Characterization of Two Gut Microbial Strains Cooperatively Promoting Multiple Sclerosis Pathogenesis.

In this study, we explored the extracellular electron transfer (EET) capabilities of two bacterial strains, OTU0001 and OTU0002, which are demonstrated in biofilm formation in mouse gut and the induction of autoimmune diseases like multiple sclerosis. OTU0002 displayed significant electrogenic behaviour, producing microbial current on an indium tin-doped oxide electrode surface, particularly in the presence of glucose, with a current density of 60 nA/cm2. The presence of cell-surface redox substrate potentially mediating EET was revealed by the redox-based staining method and electrochemical voltammetry assay. However, medium swapping analyses and the addition of flavins, a model redox mediator, suggest that the current production is dominated by soluble endogenous redox substrates in OTU0002. Given redox substrates were detected at the cell surface, the secreted redox molecule may interact with the cellular surface of OTU0002. In contrast to OTU0002, OTU0001 did not exhibit notable electrochemical activity, lacking cell-surface redox molecules. Further, the mixture of the two strains did not increase the current production from OTU0001, suggesting that OTU0001 does not support the EET mechanism of OTU0002. The present work revealed the coexistence of EET and non-EET capable pathogens in multi-species biofilm.

Putative Roles and Therapeutic Potential of the Chaperone System in Amyotrophic Lateral Sclerosis and Multiple Sclerosis.

The putative pathogenic roles and therapeutic potential of the chaperone system (CS) in amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) are reviewed to provide a bibliographic and conceptual platform for launching research on the diagnostic and therapeutic applications of CS components. Various studies suggest that dysfunction of the CS contributes to the pathogenesis of ALS and MS, and here, we identify some of the implicated CS members. The physiology and pathophysiology of the CS members can be properly understood if they are studied or experimentally or clinically manipulated for diagnostic or therapeutic purposes, bearing in mind that they belong to a physiological system with multiple interacting and dynamic components, widespread throughout the body, intra- and extracellularly. Molecular chaperones, some called heat shock protein (Hsp), are the chief components of the CS, whose canonical functions are cytoprotective. However, abnormal chaperones can be etiopathogenic factors in a wide range of disorders, chaperonopathies, including ALS and MS, according to the data reviewed. Chaperones typically form teams, and these build functional networks to maintain protein homeostasis, the canonical role of the CS. However, members of the CS also display non-canonical functions unrelated to protein homeostasis. Therefore, chaperones and other members of the CS, if abnormal, may disturb not only protein synthesis, maturation, and migration but also other physiological processes. Thus, in elucidating the role of CS components in ALS and MS, one must look at protein homeostasis abnormalities and beyond, following the clues emerging from the works discussed here.

NK Cell Levels Correlate with Disease Activity in Patients with Multiple Sclerosis on Ocrelizumab/Rituximab Therapy.

Recently, research on the pathogenesis of multiple sclerosis (MS) has focused on the role of B lymphocytes and the possibility of using specific drugs, such as Ocrelizumab and Rituximab, directed toward these cells to reduce inflammation and to slow disease progression. We aimed to evaluate the effect of Ocrelizumab/Rituximab on laboratory immune parameters and identify the predictors of treatment responses. A retrospective single-center study was conducted among patients who received infusion therapy with an anti-CD20 drug to treat MS. A total of 64 patients met the inclusion criteria, with 277 total cycles of therapy studied. Compared with the baseline values, anti-CD20 infusions resulted in absolute-value and percentage decreases in B lymphocyte levels and increased the absolute and percentage levels of NK cells 3 and 5 months after therapy (p < 0.001). After multivariate logistic regression analysis, a reduced percentage level of NK cells 3 months after infusion could predict disease activity 6 months after Ocrelizumab/Rituximab administration (p = 0.041). Lower percentage levels of NK cells 3 months after anti-CD20 infusion correlate with the presence of disease activity 6 months after therapy, confirming a possible protective role of NK cells in MS.

The relation between BTK expression and iron accumulation of myeloid cells in multiple sclerosis.

Activation of Bruton's tyrosine kinase (BTK) has been shown to play a crucial role in the proinflammatory response of B cells and myeloid cells upon engagement with B cell, Fc, Toll-like receptor, and distinct chemokine receptors. Previous reports suggest BTK actively contributes to the pathogenesis of multiple sclerosis (MS). The BTK inhibitor Evobrutinib has been shown to reduce the numbers of gadolinium-enhancing lesions and relapses in relapsing-remitting MS patients. In vitro, BTK inhibition resulted in reduced phagocytic activity and modulated BTK-dependent inflammatory signaling of microglia and macrophages. Here, we investigated the protein expression of BTK and CD68 as well as iron accumulation in postmortem control (n = 10) and MS (n = 23) brain tissue, focusing on microglia and macrophages. MS cases encompassed active, chronic active, and inactive lesions. BTK+ and iron+ cells positively correlated across all regions of interests and, along with CD68, revealed highest numbers in the center of active and at the rim of chronic active lesions. We then studied the effect of BTK inhibition in the human immortalized microglia-like HMC3 cell line in vitro. In particular, we loaded HMC3 cells with iron-dextran and subsequently administered the BTK inhibitor Evobrutinib. Iron treatment alone induced a proinflammatory phenotype and increased the expression of iron importers as well as the intracellular iron storage protein ferritin light chain (FTL). BTK inhibition of iron-laden cells dampened the expression of microglia-related inflammatory genes as well as iron-importers, whereas the iron-exporter ferroportin was upregulated. Our data suggest that BTK inhibition not only dampens the proinflammatory response but also reduces iron import and storage in activated microglia and macrophages with possible implications on microglial iron accumulation in chronic active lesions in MS.

Mechanisms Governing Oligodendrocyte Viability in Multiple Sclerosis and Its Animal Models.

Multiple sclerosis (MS) is a chronic autoimmune inflammatory demyelinating disease of the central nervous system (CNS), which is triggered by an autoimmune assault targeting oligodendrocytes and myelin. Recent research indicates that the demise of oligodendrocytes due to an autoimmune attack contributes significantly to the pathogenesis of MS and its animal model experimental autoimmune encephalomyelitis (EAE). A key challenge in MS research lies in comprehending the mechanisms governing oligodendrocyte viability and devising therapeutic approaches to enhance oligodendrocyte survival. Here, we provide an overview of recent findings that highlight the contributions of oligodendrocyte death to the development of MS and EAE and summarize the current literature on the mechanisms governing oligodendrocyte viability in these diseases.

Expanded T lymphocytes in the cerebrospinal fluid of multiple sclerosis patients are specific for Epstein-Barr-virus-infected B cells.

Epstein-Barr virus (EBV) infection has long been associated with multiple sclerosis (MS), but the role of EBV in the pathogenesis of MS is not clear. Our hypothesis is that a major fraction of the expanded clones of T lymphocytes in the cerebrospinal fluid (CSF) are specific for autologous EBV-infected B cells. We obtained blood and CSF samples from eight relapsing-remitting patients in the process of diagnosis. We stimulated cells from the blood with autologous EBV-infected lymphoblastoid cell lines (LCL), EBV, varicella zoster virus, influenza, and candida and sorted the responding cells with flow cytometry after 6 d. We sequenced the RNA for T cell receptors (TCR) from CSF, unselected blood cells, and the antigen-specific cells. We used the TCR Vβ CDR3 sequences from the antigen-specific cells to assign antigen specificity to the sequences from the CSF and blood. LCL-specific cells comprised 13.0 ± 4.3% (mean ± SD) of the total reads present in CSF and 13.3 ± 7.5% of the reads present in blood. The next most abundant antigen specificity was flu, which was 4.7 ± 1.7% of the reads in the CSF and 9.3 ± 6.6% in the blood. The prominence of LCL-specific reads was even more marked in the top 1% most abundant CSF clones with statistically significant 47% mean overlap with LCL. We conclude that LCL-specific sequences form a major portion of the TCR repertoire in both CSF and blood and that expanded clones specific for LCL are present in MS CSF. This has important implications for the pathogenesis of MS.