Cerebrospinal fluid B cells correlate with early brain inflammation in multiple sclerosis

Inhibition of GBP5 activates autophagy to alleviate inflammatory response in LPS-induced lung injury in mice

BACKGROUND

Pulmonary emphysema is a condition that causes damage to the lung tissue over time. GBP5, as part of the guanylate-binding protein family, is dysregulated in mouse pulmonary emphysema. However, the role of GBP5 in lung inflammation in ARDS remains unveiled.

METHODS

To investigate whether GBP5 regulates lung inflammation and autophagy regulation, the study employed a mouse ARDS model and MLE-12 cell culture. Vector transfection was performed for the genetic manipulation of GBP5. Then, RT-qPCR, WB and IHC staining were conducted to assess its transcriptional and expression levels. Histological features of the lung tissue were observed through HE staining. Moreover, ELISA was conducted to evaluate the secretion of inflammatory cytokines, autophagy was assessed by immunofluorescent staining, and MPO activity was determined using a commercial kit.

RESULTS

Our study revealed that GBP5 expression was altered in mouse ARDS and LPS-induced MLE-12 cell models. Moreover, the suppression of GBP5 reduced lung inflammation induced by LPS in mice. Conversely, overexpression of GBP5 diminished the inhibitory impact of LPS on ARDS during autophagy, leading to increased inflammation. In the cell line of MLE-12, GBP5 exacerbates LPS-induced inflammation by blocking autophagy.

CONCLUSION

The study suggests that GBP5 facilitates lung inflammation and autophagy regulation. Thus, GBP5 could be a potential therapeutic approach for improving ARDS treatment outcomes, but further research is required to validate these findings.

Key characteristics of anti-CD20 monoclonal antibodies and clinical implications for multiple sclerosis treatment

The recent success of anti-CD20 monoclonal antibody therapies in the treatment of multiple sclerosis (MS) has highlighted the role of B cells in the pathogenesis of MS. In people with MS, the inflammatory characteristics of B-cell activity are elevated, leading to increased pro-inflammatory cytokine release, diminished anti-inflammatory cytokine production and an accumulation of pathogenic B cells in the cerebrospinal fluid. Rituximab, ocrelizumab, ofatumumab, ublituximab and BCD-132 are anti-CD20 therapies that are either undergoing clinical development, or have been approved, for the treatment of MS. Despite CD20 being a common target for these therapies, differences have been reported in their mechanistic, pharmacological and clinical characteristics, which may have substantial clinical implications. This narrative review explores key characteristics of these therapies. By using clinical trial data and real-world evidence, we discuss their mechanisms of action, routes of administration, efficacy (in relation to B-cell kinetics), safety, tolerability and convenience of use. Clinicians, alongside patients and their families, should consider the aspects discussed in this review as part of shared decision-making discussions to improve outcomes and health-related quality of life for people living with MS.

Understanding immune microenvironment alterations in the brain to improve the diagnosis and treatment of diverse brain diseases

Abnormal inflammatory states in the brain are associated with a variety of brain diseases. The dynamic changes in the number and function of immune cells in cerebrospinal fluid (CSF) are advantageous for the early prediction and diagnosis of immune diseases affecting the brain. The aggregated factors and cells in inflamed CSF may represent candidate targets for therapy. The physiological barriers in the brain, such as the blood‒brain barrier (BBB), establish a stable environment for the distribution of resident immune cells. However, the underlying mechanism by which peripheral immune cells migrate into the brain and their role in maintaining immune homeostasis in CSF are still unclear. To advance our understanding of the causal link between brain diseases and immune cell status, we investigated the characteristics of immune cell changes in CSF and the molecular mechanisms involved in common brain diseases. Furthermore, we summarized the diagnostic and treatment methods for brain diseases in which immune cells and related cytokines in CSF are used as targets. Further investigations of the new immune cell subtypes and their contributions to the development of brain diseases are needed to improve diagnostic specificity and therapy.

The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by the destruction of the myelin sheath of the neuronal axon in the central nervous system. Many risk factors, including environmental, epigenetic, genetic, and lifestyle factors, are responsible for the development of MS. It has long been thought that only adaptive immune cells, especially autoreactive T cells, are responsible for the pathophysiology; however, recent evidence has indicated that innate immune cells are also highly involved in disease initiation and progression. Here, we compile the available data regarding the role immune cells play in MS, drawn from both human and animal research. While T and B lymphocytes, chiefly enhance MS pathology, regulatory T cells (Tregs) may serve a more protective role, as can B cells, depending on context and location. Cells chiefly involved in innate immunity, including macrophages, microglia, astrocytes, dendritic cells, natural killer (NK) cells, eosinophils, and mast cells, play varied roles. In addition, there is evidence regarding the involvement of innate-like immune cells, such as γδ T cells, NKT cells, MAIT cells, and innate-like B cells as crucial contributors to MS pathophysiology. It is unclear which of these cell subsets are involved in the onset or progression of disease or in protective mechanisms due to their plastic nature, which can change their properties and functions depending on microenvironmental exposure and the response of neural networks in damage control. This highlights the need for a multipronged approach, combining stringently designed clinical data with carefully controlled in vitro and in vivo research findings, to identify the underlying mechanisms so that more effective therapeutics can be developed.

Bioavailable central nervous system disease-modifying therapies for multiple sclerosis

Disease-modifying therapies for relapsing multiple sclerosis reduce relapse rates by suppressing peripheral immune cells but have limited efficacy in progressive forms of the disease where cells in the central nervous system play a critical role. To our knowledge, alemtuzumab, fumarates (dimethyl, diroximel, and monomethyl), glatiramer acetates, interferons, mitoxantrone, natalizumab, ocrelizumab, ofatumumab, and teriflunomide are either limited to the periphery or insufficiently studied to confirm direct central nervous system effects in participants with multiple sclerosis. In contrast, cladribine and sphingosine 1-phosphate receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are central nervous system-penetrant and could have beneficial direct central nervous system properties.

Conversion Predictors of Clinically Isolated Syndrome to Multiple Sclerosis in Mexican Patients: A Prospective Study

BACKGROUND

Clinically Isolated Syndrome (CIS) is the first clinical episode suggestive of Clinical Definite Multiple Sclerosis (CDMS). There are no reports on possible predictors of conversion to CDMS in Mexican mestizo patients.

AIM OF THE STUDY

To investigate immunological markers, clinical and paraclinical findings, and the presence of herpesvirus DNA to predict the transition from CIS to CDMS in Mexican patients.

METHODS

A single-center prospective cohort study was conducted with newly diagnosed patients with CIS in Mexico between 2006 and 2010. Clinical information, immunophenotype, serum cytokines, anti-myelin protein immunoglobulins, and herpes viral DNA were determined at the time of diagnosis.

RESULTS

273 patients diagnosed with CIS met the enrolment criteria; after 10 years of follow-up, 46% met the 2010 McDonald criteria for CDMS. Baseline parameters associated with conversion to CDMS were motor symptoms, multifocal syndromes, and alterations of somatosensory evoked potentials. The presence of at least one lesion on magnetic resonance imaging was the main factor associated with an increased risk of conversion to CDMS (RR 15.52, 95% CI 3.96-60.79, p = 0.000). Patients who converted to CDMS showed a significantly lower percentage of circulating regulatory T cells, cytotoxic T cells, and B cells, and the conversion to CDMS was associated with the presence of varicella-zoster virus and herpes simplex virus 1 DNA in cerebrospinal fluid and blood.

CONCLUSION

There is scarce evidence in Mexico regarding the demographic and clinical aspects of CIS and CDMS. This study shows several predictors of conversion to CDMS to be considered in Mexican patients with CIS.

The immunology of multiple sclerosis

Our incomplete understanding of the causes and pathways involved in the onset and progression of multiple sclerosis (MS) limits our ability to effectively treat this complex neurological disease. Recent studies explore the role of immune cells at different stages of MS and how they interact with cells of the central nervous system (CNS). The findings presented here begin to question the exclusivity of an antigen-specific cause and highlight how seemingly distinct immune cell types can share common functions that drive disease. Innovative techniques further expose new disease-associated immune cell populations and reinforce how environmental context is critical to their phenotype and subsequent role in disease. Importantly, the differentiation of immune cells into a pathogenic state is potentially reversible through therapeutic manipulation. As such, understanding the mechanisms that provide plasticity to causal cell types is likely key to uncoupling these disease processes and may identify novel therapeutic targets that replace the need for cell ablation.

Pathogenic autoantibodies in multiple sclerosis - from a simple idea to a complex concept

The role of autoantibodies in multiple sclerosis (MS) has been enigmatic since the first description, many decades ago, of intrathecal immunoglobulin production in people with this condition. Some studies have indicated that MS pathology is heterogeneous, with an antibody-associated subtype - characterized by B cells (in varying quantities), antibodies and complement - existing alongside other subtypes with different pathologies. However, subsequent evidence suggested that some cases originally diagnosed as MS with autoantibody-mediated demyelination were more likely to be neuromyelitis optica spectrum disorder or myelin oligodendrocyte glycoprotein antibody-associated disease. These findings raise the important question of whether an autoantibody-mediated MS subtype exists and whether pathogenic MS-associated autoantibodies remain to be identified. Potential roles of autoantibodies in MS could range from specific antibodies defining the disease to a non-disease-specific amplification of cellular immune responses and other pathophysiological processes. In this Perspective, we review studies that have attempted to identify MS-associated autoantibodies and provide our opinions on their possible roles in the pathophysiology of MS.

B Cells Specific CpG Induces High IL-10 and IL-6 Expression In Vitro in Neuro-Behçet's Disease

Remitting-RelapsingMultiple Sclerosis (RRMS) and Neuro-Behçet Disease (NBD) are two chronic neuroinflammatory disorders leading to neurological damage. Herein, we investigated in these patients the IL-10-producing cells during the early stages of these disorders. Cellular and molecular investigations were carried out on treatment naive patients suffering from RRMS and NBD recruited at the first episode of clinical relapse. Our findings demonstrate that CSF-B cells from NBD patients, but not RRMS, are the major source of intrathecal IL-10 as compared to T-CD4 cells. Moreover, we showed a lower expression of TGF-β and IL35, in the CSF cells of NBD patients as compared to the control group. Specific in vitro CpG stimulation of peripheral blood B cells from NBD patients resulted in a concomitant early mRNA expression of IL6 and IL10 but was limited to IL10 for RRMS patients. Furthermore, mRNA expression of IL-6 and IL-10 receptors was assessed and intriguingly IL6ST receptor subunit was significantly lower in NBD CSF, but not RRMS while IL10RB was increased in both. Deciphering the role of increased IL-10-producing B cells and IL10RB despite relapsing disease as well as the discordant expression of IL6 and IL6ST may pave the way for a better understanding of the pathophysiology of these neuro-inflammatory disorders.

Effects of a Fully Humanized Type II Anti-CD20 Monoclonal Antibody on Peripheral and CNS B Cells in a Transgenic Mouse Model of Multiple Sclerosis

Successful therapy with anti-CD20 monoclonal antibodies (mAbs) has reinforced the key role of B cells in the immunopathology of multiple sclerosis (MS). This study aimed to determine the effects of a novel class of anti-CD20 mAbs on vascular and extravascular central nervous system (CNS)-infiltrating B cells in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Male hCD20xhIgR3 mice and wild-type C57BL/6 (B6) mice were immunized with human myelin oligodendrocyte glycoprotein (MOG)_1–125 to induce EAE. While hCD20xhIgR3 mice were injected intravenously with an anti-human CD20 mAb (5 mg/kg) (rituximab (a type I anti-CD20 mAb) or obinutuzumab (a type II anti-CD20 mAb), B6 mice received the anti-mouse CD20 antibody 18B12. Neither mAb affected clinical disease or serum antibody levels. Obinutuzumab and rituximab had an impact on splenic and CNS-infiltrated B cells with slightly differential depletion efficacy. Additionally, obinutuzumab had beneficial effects on spinal cord myelination. B cell depletion rates in the 18B12/B6 model were comparable with those observed in obinutuzumab-treated hCD20xhIgR3 mice. Our results demonstrate the usefulness of anti-CD20 mAbs for the modulation of B cell-driven peripheral immune response and CNS pathology, with type II antibodies potentially being superior to type I in the depletion of tissue-infiltrating B cells.

Inhibiting microglia proliferation after spinal cord injury improves recovery in mice and nonhuman primates

No curative treatment is available for any deficits induced by spinal cord injury (SCI). Following injury, microglia undergo highly diverse activation processes, including proliferation, and play a critical role on functional recovery.

In a translational objective, we investigated whether a transient pharmacological reduction of microglia proliferation after injury is beneficial for functional recovery after SCI in mice and nonhuman primates.

Methods: The colony stimulating factor-1 receptor (CSF1R) regulates proliferation, differentiation, and survival of microglia. We orally administrated GW2580, a CSF1R inhibitor that inhibits microglia proliferation. In mice and nonhuman primates, we then analyzed treatment outcomes on locomotor function and spinal cord pathology. Finally, we used cell-specific transcriptomic analysis to uncover GW2580-induced molecular changes in microglia.

Results: First, transient post-injury GW2580 administration in mice improves motor function recovery, promotes tissue preservation and/or reorganization (identified by coherent anti-stokes Raman scattering microscopy), and modulates glial reactivity.

Second, post-injury GW2580-treatment in nonhuman primates reduces microglia proliferation, improves motor function recovery, and promotes tissue protection.

Finally, GW2580-treatment in mice induced down-regulation of proliferation-associated transcripts and inflammatory associated genes in microglia that may account for reduced neuroinflammation and improved functional recovery following SCI.

Conclusion: Thus, a transient oral GW2580 treatment post-injury may provide a promising therapeutic strategy for SCI patients and may also be extended to other central nervous system disorders displaying microglia activation.

Peripheral blood B cell subset ratios and expression levels of B cell-associated genes are altered in benign multiple sclerosis

The interplay between the immune system, sleep dysfunction and cognitive impairment participates in the progression of disability in multiple sclerosis (MS). Our aim was to identify molecular pathways and B cell associated with separate components of MS disability. Benign MS, non-benign MS patients and healthy controls were recruited. Patients underwent polysomnography and cognitive studies. Microarray and bioinformatics analysis performed using peripheral blood mononuclear cell samples identified B cell-associated genes with the most significantly altered expression. Expression levels of these genes were validated by real-time PCR and peripheral blood cell subsets were examined by flow cytometry. Putative correlations among clinical and laboratory parameters were investigated by correlation network analysis. Sleep and cognitive functions were equally impaired in BMS and NBMS. BMS patients showed significantly reduced memory B cell and increased regulatory B cell percentages than NBMS patients. Among genes that were selected by bioinformatics, levels of BLK, BLNK, BANK1, FCRL2, TGFB1 and KCNS3 genes were significantly different among study subgroups. Correlation network analysis showed associations among physical-cognitive disability and sleep dysfunction measures of MS versus expression levels of selected genes. BMS and NBMS differ by physical disability but not cognitive and sleep dysfunction. Different components of disability in MS are associated with peripheral blood B cell ratios and B cell related gene expression levels. Thus, it is likely that altered B cell functions participate in the progression of disability in MS.

CSF plasmablasts differentiate MS from other neurologic disorders

Multiparametric flow cytometry (FC) of CSF allows one to easily estimate the percentage of lymphocyte subpopulations in CSF. We hypothesized that an increased ratio of B-lineage cells in CSF of MS patients, as assessed with FC, could be useful for diagnostics. We analyzed CSF of 137 patients (70 MS, 24 infectious/autoimmune neurologic disorders (INDs), and 43 non-infectious/autoimmune neurologic disorders (NINDs)), and showed that CSF plasmablasts of >0.1% had a sensitivity of 40% for MS and specificity of 92% when comparing MS and IND, while plasmablasts of >0.25% had sensitivity of 36%, and 100% specificity.

B Cells in Multiple Sclerosis and Virus-Induced Neuroinflammation

Neuroinflammation can be defined as an inflammatory response within the central nervous system (CNS) mediated by a complex crosstalk between CNS-resident and infiltrating immune cells from the periphery. Triggers for neuroinflammation not only include pathogens, trauma and toxic metabolites, but also autoimmune diseases such as neuromyelitis optica spectrum disorders and multiple sclerosis (MS) where the inflammatory response is recognized as a disease-escalating factor. B cells are not considered as the first responders of neuroinflammation, yet they have recently gained focus as a key component involved in the disease pathogenesis of several neuroinflammatory disorders like MS. Traditionally, the prime focus of the role of B cells in any disease, including neuroinflammatory diseases, was their ability to produce antibodies. While that may indeed be an important contribution of B cells in mediating disease pathogenesis, several lines of recent evidence indicate that B cells are multifunctional players during an inflammatory response, including their ability to present antigens and produce an array of cytokines. Moreover, interaction between B cells and other cellular components of the immune system or nervous system can either promote or dampen neuroinflammation depending on the disease. Given that the interest in B cells in neuroinflammation is relatively new, the precise roles that they play in the pathophysiology and progression of different neuroinflammatory disorders have not yet been well-elucidated. Furthermore, the possibility that they might change their function during the course of neuroinflammation adds another level of complexity and the puzzle remains incomplete. Indeed, advancing our knowledge on the role of B cells in neuroinflammation would also allow us to tackle these disorders better. Here, we review the available literature to explore the relationship between autoimmune and infectious neuroinflammation with a focus on the involvement of B cells in MS and viral infections of the CNS.

Transcriptomic and clonal characterization of T cells in the human central nervous system

T cells provide critical immune surveillance to the central nervous system (CNS), and the cerebrospinal fluid (CSF) is thought to be a main route for their entry. Further characterization of the state of T cells in the CSF in healthy individuals is important for understanding how T cells provide protective immune surveillance without damaging the delicate environment of the CNS and providing tissue-specific context for understanding immune dysfunction in neuroinflammatory disease. Here, we have profiled T cells in the CSF of healthy human donors and have identified signatures related to cytotoxic capacity and tissue adaptation that are further exemplified in clonally expanded CSF T cells. By comparing profiles of clonally expanded T cells obtained from the CSF of patients with multiple sclerosis (MS) and healthy donors, we report that clonally expanded T cells from the CSF of patients with MS have heightened expression of genes related to T cell activation and cytotoxicity.

Multi-Platform Characterization of Cerebrospinal Fluid and Serum Metabolome of Patients Affected by Relapsing-Remitting and Primary Progressive Multiple Sclerosis

Background: Multiple sclerosis (MS) is a chronic immunemediated disease of the central nervous system with a highly variable clinical presentation and disease progression. In this study, we investigate the metabolomics profile of patients affected by relapsing–remitting MS (RRMS)and primary progressive MS (PPMS), in order to find potential biomarkers to distinguish between the two forms. Methods: Cerebrospinal Fluid CSF and blood samples of 34 patients (RRMS n = 22, PPMS n = 12) were collected. Nuclear magnetic resonance (¹H-NMR) and mass spectrometry (coupled with a gas chromatography and liquid chromatography) were used as analytical techniques. Subsequently, a multivariate statistical analysis was performed; the resulting significant variables underwent U-Mann–Whitney test and correction for multiple comparisons. Receiver Operating Characteristic ROC curves were built and the pathways analysis was conducted. Results: The analysis of the serum and the CSF of the two classes, allowed the identification of several altered metabolites (lipids, biogenic amines, and amino acids). The pathways analysis indicated the following pathways were affected: Glutathione metabolism, nitrogen metabolism, glutamine–glutamate metabolism, arginine–ornithine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis etc. Conclusion: The analysis allowed the identification of a set of metabolites able to classify RRMS and PPMS patients, each of whom express different patterns of metabolites in the two biofluids.

Biomarkers of Multiple Sclerosis

The search for an ideal multiple sclerosis biomarker with good diagnostic value, prognostic reference and an impact on clinical outcome has yet to be realized and is still ongoing. The aim of this review is to establish an overview of the frequent biomarkers for multiple sclerosis that exist to date. The review summarizes the results obtained from electronic databases, as well as thorough manual searches. In this review the sources and methods of biomarkers extraction are described; in addition to the description of each biomarker, determination of the prognostic, diagnostic, disease monitoring and treatment response values besides clinical impact they might possess. We divided the biomarkers into three categories according to the achievement method: laboratory markers, genetic-immunogenetic markers and imaging markers. We have found two biomarkers at the time being considered the gold standard for MS diagnostics. Unfortunately, there does not exist a single solitary marker being able to present reliable diagnostic value, prognostic value, high sensitivity and specificity as well as clinical impact. We need more studies to find the best biomarker for MS.

Intrathecal B-cell accumulation and axonal damage distinguish MRI-based benign from aggressive onset in MS

Objective

We explored the incremental value of adding multiple disease activity biomarkers in CSF and serum for distinguishing MRI-based benign from aggressive MS in early disease course.

Methods

Ninety-three patients diagnosed with clinically isolated syndrome (CIS) or early MS were divided into 3 nonoverlapping severity groups defined by objective MRI criteria. Ninety-seven patients with noninflammatory neurologic disorders and 48 patients with other inflammatory neurologic diseases served as controls. Leukocyte subsets in the CSF were analyzed by flow cytometry. CSF neurofilament light chain (NfL) and chitinase-3-like protein 1 (CHI3L1) levels were measured by ELISA. Serum NfL levels were examined using single molecule array technology.

Results

CSF CD20+/CD14+ ratios and NfL levels in CSF and serum were significantly different between high and low MRI severity groups, whereas no difference was found for CSF CHI3L1 levels. NfL levels in CSF and serum highly correlated. Receiver operating characteristic analysis demonstrated that the cumulative sums combining CSF CD20+/CD14+ ratios and NfL levels in serum or CSF considerably improved diagnostic accuracy. A composite score built from these 2 cumulative sums best distinguished MRI severity. These findings were validated by support vector machine analysis, which confirmed that the accuracy of the cumulative sums and composite score outperforms single biomarkers.

Conclusion

Patients with extreme manifestations of CIS or early MS defined by strict MRI parameters can be best distinguished by combining markers of intrathecal B-cell accumulation and axonal damage. This could stratify individual treatment decisions toward a more personalized immunotherapy.

The Interaction between Viral and Environmental Risk Factors in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic debilitating inflammatory disease of unknown ethology targeting the central nervous system (CNS). MS has a polysymptomatic onset and is usually first diagnosed between the ages of 20–40 years. The pathology of the disease is characterized by immune mediated demyelination in the CNS. Although there is no clinical finding unique to MS, characteristic symptoms include sensory symptoms visual and motor impairment. No definitive trigger for the development of MS has been identified but large-scale population studies have described several epidemiological risk factors for the disease. This list is a confusing one including latitude, vitamin D (vitD) levels, genetics, infection with Epstein Barr Virus (EBV) and endogenous retrovirus (ERV) reactivation. This review will look at the evidence for each of these and the potential links between these disparate risk factors and the known molecular disease pathogenesis to describe potential hypotheses for the triggering of MS pathology.

Differences in Intercellular Communication During Clinical Relapse and Gadolinium-Enhanced MRI in Patients With Relapsing Remitting Multiple Sclerosis: A Study of the Composition of Extracellular Vesicles in Cerebrospinal Fluid

This study was designed based on the hypothesis that changes in both the levels and surface marker expression of extracellular vesicles (EVs) isolated from the cerebrospinal fluid (CSF) may be associated with the clinical form, disease activity, and severity of multiple sclerosis (MS). The analyzes were performed on subjects affected by MS or other neurological disorders. EVs, which were isolated by ultracentrifugation of CSF samples, were characterized by flow cytometry. A panel of fluorescent antibodies was used to identify the EV origin: CD4, CCR3, CCR5, CD19, and CD200, as well as isolectin IB4. The Mann-Whitney U-test and Kruskal-Wallis test were used for statistical analyzes. EVs isolated from the CSF were more abundant in patients with progressive MS and in those with a clinically isolated syndrome than in all the other groups examined. Furthermore, an important change in the number of EVs and in their surface marker expression occurred during active phases of MS [i.e., clinical relapses and the presence of enhancing lesions on magnetic resonance imaging (MRI)]. In particular, the number of CSF-EVs increased in patients affected by MS during clinical relapse; this finding was associated with a decrease in the number of CD19+/CD200+ (naïve B cells) EVs. These markers are expressed by immature and naïve B lymphocytes, and to the best of our knowledge, this double staining has never been associated with MS, but their reduction has been observed in patients with another type of Th1 cell-mediated autoimmune disease. In contrast, the presence of lesions in the brain and spine on gadolinium-enhanced MRI was associated with an increase in the numbers of CCR3+/CCR5+ (subset of CD8 memory T cells), CD4+/CCR3+ (Th2 cells), and CD4+/CCR5+ (Th1 cells) CSF-EVs. Two points are worth emphasizing: (i) the data obtained in this study confirm that CSF-EVs represent a potentially promising tool to identify biomarkers specific for different phases of MS; and (ii) Considering the role of EVs in intercellular communication, our results provide some insights that improve our understanding of the relationships among some of the cell types that are mainly involved in MS pathogenesis (e.g., lymphocytes, glia, and neurons).

Predictable Irreversible Switching Between Acute and Chronic Inflammation

Many a disease associates with inflammation. Upon binding of antigen-antibody complexes to immunoglobulin-like receptors, mast cells release tumor necrosis factor-α and proteases, causing fibroblasts to release endogenous antigens that may be cross reactive with exogenous antigens. We made a predictive dynamic map of the corresponding extracellular network. In silico, this map cleared bacterial infections, via acute inflammation, but could also cause chronic inflammation. In the calculations, limited inflammation flipped to strong inflammation when cross-reacting antigen exceeded an “On threshold.” Subsequent reduction of the antigen load to below this “On threshold” did not remove the strong inflammation phenotype unless the antigen load dropped below a much lower and subtler “Off” threshold. In between both thresholds, the network appeared caught either in a “low” or a “high” inflammatory state. This was not simply a matter of bi-stability, however, the transition to the “high” state was temporarily revertible but ultimately irreversible: removing antigen after high exposure reduced the inflammatory phenotype back to “low” levels but if then the antigen dosage was increased only a little, the high inflammation state was already re-attained. This property may explain why the high inflammation state is indeed “chronic,” whereas only the naive low-inflammation state is “acute.” The model demonstrates that therapies of chronic inflammation such as with anti-IgLC should require fibroblast implantation (or corresponding stem cell activation) for permanence in order to redress the irreversible transition.

The intrathecal polyspecific antiviral immune response (MRZ reaction): A potential cerebrospinal fluid marker for multiple sclerosis diagnosis

We tested the performance of MRZ-reaction, an intrathecal humoral immune response against-Measles (M), Rubella (R) and Varicella Zoster (Z) viruses, in multiple sclerosis (MS) diagnosis. The MRZ-reaction was significantly more positive in MS than in non-MS group with a specificity of 91.9%. In MS group, the RZ-profile was the most prevalent and the R-specific antibody-index was correlated to the number of oligoclonal bands (OCB) in CSF. Interestingly, the MRZ-reaction was detected in 53% of OCB-negative-MS patients. The MRZ-reaction seems to be a relevant CSF diagnostic marker of MS disease. The likely relation between its positivity and the vaccination status deserves to be investigated.

Western lifestyle and immunopathology of multiple sclerosis

There is increasing evidence for a sudden and unprecedented rise in the incidence of multiple sclerosis (MS) in Westernized countries over the past decades, emphasizing the role of environmental factors. Among many candidates, rapid changes in dietary habits seem to play a role in the pathogenesis of MS. Here, we summarize and discuss the available evidence for the role of dietary nutrients, such as table salt, fatty acids, and flavonoids, in the development and pathogenesis of MS. We also discuss new and emerging risk factors accompanying Western lifestyle, such as shift work, sleep, and circadian disruption.

Clonal relationships of CSF B cells in treatment-naive multiple sclerosis patients

A role of B cells in multiple sclerosis (MS) is well established, but there is limited understanding of their involvement during active disease. Here, we examined cerebrospinal fluid (CSF) and peripheral blood (PB) B cells in treatment-naive patients with MS or high-risk clinically isolated syndrome. Using flow cytometry, we found increased CSF lymphocytes with a disproportionate increase of B cells compared with T cells in patients with gadolinium-enhancing (Gd+) lesions on brain MRI. Ig gene heavy chain variable region (Ig-VH) repertoire sequencing of CSF and PB B cells revealed clonal relationships between intrathecal and peripheral B cell populations, which could be consistent with migration of B cells to and activation in the CNS in active MS. In addition, we found evidence for bystander immigration of B cells from the periphery, which could be supported by a CXCL13 gradient between CSF and blood. Understanding what triggers B cells to migrate and home to the CNS may ultimately aid in the rational selection of therapeutic strategies to limit progression in MS.

Cerebrospinal fluid B cells and disease progression in multiple sclerosis - A longitudinal prospective study

BACKGROUND

There is evidence that B cells play an important role in disease pathology of multiple sclerosis (MS). The aim of this prospective observational study was to determine the predictive value of cerebrospinal fluid (CSF) B cell subtypes in disease evolution of patients with MS.

MATERIALS AND METHODS

128 patients were included between 2004 and 2012. Median follow up time was 7.9 years (range 3.3-10.8 years). 10 patients were lost to follow-up. 32 clinically isolated syndrome- (CIS), 25 relapsing remitting MS- (RRMS), 2 secondary progressive MS- (SPMS) and 9 primary progressive MS- (PPMS) patients were included. The control group consisted of 40 patients with other neurological diseases (OND). CSF samples were analyzed for routine diagnostic parameters. B cell phenotypes were characterized by flow cytometry using CD19 and CD138 specific antibodies. Standardized baseline brain MRI was conducted at the time of diagnostic lumbar puncture. Main outcome variables were likelihood of progressive disease course, EDSS progression, conversion to clinical definite MS (CDMS) and relapse rate.

RESULTS

CSF mature B cells (CD19+CD138-) were increased in bout-onset MS compared to PPMS (p<0.05) and OND (p<0.001), whereas plasma blasts (CD19+CD138+) were increased in bout-onset MS (p<0.001) and PPMS (p<0.05) compared to OND. CSF B cells did not predict a progressive disease course, EDSS progression, an increased relapse rate or the conversion to CDMS. Likelihood of progressive disease course (p<0.05) and EDSS (p<0.01) was predicted by higher age at baseline, whereas conversion to CDMS was predicted by a lower age at onset (p<0.01) and the presence of ≥9 MRI T2 lesions (p<0.05).

CONCLUSION

We detected significant differences in the CSF B cell subsets between different clinical MS subtypes and OND patients. CSF B cells were neither predictive for disease and EDSS progression nor conversion to CDMS after a CIS.

CXCL10 and CXCL13 chemokines in patients with relapsing remitting and primary progressive multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system characterized by a variable clinical course. Different pathogenic mechanisms responsible for relapsing remitting (RRMS) and primary progressive multiple sclerosis (PPMS) are modulated by immunological process with important role of chemokine network. CXCL10 and CXCL13 chemokines act as chemoattractants and modulators of proinflammatory reactions promoting process of demyelination. In the present study, we investigated the concentrations of CXCL10 and CXCL13 in serum and cerebrospinal fluid (CSF) of patients with RRMS and PPMS.

MATERIALS AND METHODS

The study groups comprised 25 RRMS patients (39,5±12years), 24 PPMS patients (49,9±10,5years), 31 healthy individuals (36±10,4years) with tension headache without symptoms of inflammatory diseases. A quantitive test kit based on ELISA has been used for chemokines measurement. Correlations analysis between the levels of CXCL10, CXCL13 and patient age, duration of MS, EDSS and IgG index were done.

RESULTS

The mean concentration of CXCL10 in the CSF was statistically significantly higher in RRMS in comparison with the control group. The mean concentration of CXCL13 in the CSF was significantly higher in RRMS and PPMS than in the control group. The results have shown that in the stable phase of MS without relapse, mean concentration of CXCL10 and CXCL13 in CSF did not differ significantly between RRMS and PPMS. In PPMS a positive correlation between IgG index and CSF CXCL10 level or CSF CXCL13 level was observed. In RRMS a positive correlation between IgG index and CSF CXCL13 level was observed.

CONCLUSIONS

These data indicate involvement of CXCL10 and CXCL13 chemokines in immunopathogenetic mechanisms in MS. There was no significant difference between mean CXCL10 or CXCL13 concentrations in the CSF in both RRMS and PPMS patients. No significant correlations were found between patient age and chemokines levels in theCSF in all groups. It suggest that these chemokines play similar role in inflammatory process despite more pronounced neurodegenerative process in PPMS.

Progressive multiple sclerosis: from pathogenic mechanisms to treatment

During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved in progressive multiple sclerosis, correlations between histopathology and magnetic resonance imaging studies, along with possible new therapeutic approaches.

Elevated Levels of Proinflammatory Cytokines in Cerebrospinal Fluid of Multiple Sclerosis Patients

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease characterized by chronic brain inflammation. Leukocyte infiltration of brain tissue causes inflammation, demyelination, and the subsequent formation of sclerotic plaques, which are a hallmark of MS. Activation of proinflammatory cytokines is essential for regulation of lymphocyte migration across the blood–brain barrier. We demonstrate increased levels of many cytokines, including IL-2RA, CCL5, CCL11, MIF, CXCL1, CXCL10, IFNγ, SCF, and TRAIL, were upregulated in cerebrospinal fluid (CSF), whereas IL-17, CCL2, CCL3, CCL4, and IL-12(p40) were activated in MS serum. Interaction analysis of cytokines in CSF demonstrated a connection between IFNγ and CCL5 as well as MIF. Many cells can contribute to production of these cytokines including CD8 and Th1 lymphocytes and astrocytes. Therefore, we suggest that IFNγ released by Th1 lymphocytes can activate astrocytes, which then produce chemoattractants, including CCL5 and MIF. These chemokines promote an inflammatory milieu and interact with multiple chemokines including CCL27 and CXCL1. Of special note, upregulation of CCL27 was found in CSF of MS cases. This observation is the first to demonstrate CCL27 as a potential contributor of brain pathology in MS. Our data suggest that CCL27 may be involved in activation and migration of autoreactive encephalitogenic immune effectors in the brain. Further, our data support the role of Th1 lymphocytes in the pathogenesis of brain inflammation in MS, with several cytokines playing a central role.

B-cell populations discriminate between pediatric- and adult-onset multiple sclerosis

Objective:

To comparatively assess the B-cell composition in blood and CSF of patients with pediatric-onset multiple sclerosis (pedMS) and adult-onset multiple sclerosis (adMS).

Methods:

In this cross-sectional study, we obtained blood and CSF samples from 25 patients with pedMS (8–18 years) and 40 patients with adMS (23–65 years) and blood specimens from 66 controls (1–55 years). By using multicolor flow cytometry, we identified naive, transitional, isotype class-switched memory, nonswitched memory, and double-negative memory B-cell subsets as well as plasmablasts (PB) and terminally differentiated plasma cells (PC). Flow cytometric data were compared to concentrations of B-cell-specific cytokines in serum and CSF as determined by ELISA.

Results:

Frequencies of circulating naive B-cells decreased with higher age in controls but not in patients with multiple sclerosis (MS). B-cell patterns in CSF differed between pedMS and adMS with an acute relapse: in pedMS-derived CSF samples, high frequencies of nonswitched memory B cells and PB were present, whereas class-switched memory B cells and PC dominated in the CSF of patients with adMS. In pedMS, PB were also elevated in the periphery. Accumulation of PB in the CSF correlated with high intrathecal CXCL-13 levels and augmented intrathecal synthesis of immunoglobulin G and immunoglobulin M.

Conclusions:

We demonstrate distinct changes in intrathecal B-cell homeostasis in patients with pedMS during active disease, which differ from those in adults by an expansion of plasmablasts in blood and CSF and similarly occur in prototypic autoantibody-driven autoimmune disorders. This emphasizes the particular importance of activated B-lymphocyte subsets for disease progression in the earliest clinical stages of MS.

Brain inflammation is accompanied by peripheral inflammation in Cstb -/- mice, a model for progressive myoclonus epilepsy

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is an autosomal recessively inherited childhood-onset neurodegenerative disorder, characterized by myoclonus, seizures, and ataxia. Mutations in the cystatin B gene (CSTB) underlie EPM1. The CSTB-deficient (Cstb -/- ) mouse model recapitulates key features of EPM1, including myoclonic seizures. The mice show early microglial activation that precedes seizure onset and neuronal loss and leads to neuroinflammation. We here characterized the inflammatory phenotype of Cstb -/- mice in more detail. We found higher concentrations of chemokines and pro-inflammatory cytokines in the serum of Cstb -/- mice and higher CXCL13 expression in activated microglia in Cstb -/- compared to control mouse brains. The elevated chemokine levels were not accompanied by blood-brain barrier disruption, despite increased brain vascularization. Macrophages in the spleen and brain of Cstb -/- mice were predominantly pro-inflammatory. Taken together, these data show that CXCL13 expression is a hallmark of microglial activation in Cstb -/- mice and that the brain inflammation is linked to peripheral inflammatory changes, which might contribute to the disease pathology of EPM1.

Association between human herpesvirus & human endogenous retrovirus and MS onset & progression

This review discusses the role of Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and human endogenous retroviruses (HERVs) in the onset and progression of multiple sclerosis (MS). Although EBV has been established as one of the causal factors in MS onset, its role in MS progression is still uncertain. Moreover, interactions between EBV and other risk factor on MS development still need more investment. With less consistent evidence than EBV, HHV6 has also been implicated in the pathogenesis of MS; moreover, it showed a closer connection with the disease activity. Recent studies found that HERVs were associated with the development and progression of MS. Some antiviral treatments have shown promise for clinical interventions in the future. Future studies are yet needed to fully clarify the role of these agents in MS onset and disease course and the modes by which they realise these effects.

Enterococcus faecium strain L-3 and glatiramer acetate ameliorate experimental allergic encephalomyelitis in rats by affecting different populations of immune cells

The effect of probiotic Enterococcus faecium strain L-3 was studied in rats with experimental allergic encephalomyelitis (EAE). Glatiramer acetate (GA) was used as control drug. E. faecium strain L-3 and GA both were able to reduce the severity of EAE in a similar fashion. Both approaches increased the proportion of EAE resistant rats and rats with mild disease, prolonged the inductive phase of EAE and reduced the disease duration. Study of the phenotypes of immune cells in blood revealed the differences in immunoregulatory pathways that mediate the protective action of probiotic or GA treatment of EAE. The presence of pronounced protective and immunomodulating effects of the probiotic E. faecium strain L-3 opens an opportunity of its application for the treatment of multiple sclerosis.

Current Evidence for a Role of the Kynurenine Pathway of Tryptophan Metabolism in Multiple Sclerosis

The kynurenine pathway (KP) is the major metabolic pathway of the essential amino acid tryptophan (TRP). Stimulation by inflammatory molecules, such as interferon-γ (IFN-γ), is the trigger for induction of the KP, driving a complex cascade of production of both neuroprotective and neurotoxic metabolites, and in turn, regulation of the immune response and responses of brain cells to the KP metabolites. Consequently, substantial evidence has accumulated over the past couple of decades that dysregulation of the KP and the production of neurotoxic metabolites are associated with many neuroinflammatory and neurodegenerative diseases, including Parkinson’s disease, AIDS-related dementia, motor neurone disease, schizophrenia, Huntington’s disease, and brain cancers. In the past decade, evidence of the link between the KP and multiple sclerosis (MS) has rapidly grown and has implicated the KP in MS pathogenesis. KP enzymes, indoleamine 2,3-dioxygenase (IDO-1) and tryptophan dioxygenase (highest expression in hepatic cells), are the principal enzymes triggering activation of the KP to produce kynurenine from TRP. This is in preference to other routes such as serotonin and melatonin production. In neurological disease, degradation of the blood–brain barrier, even if transient, allows the entry of blood monocytes into the brain parenchyma. Similar to microglia and macrophages, these cells are highly responsive to IFN-γ, which upregulates the expression of enzymes, including IDO-1, producing neurotoxic KP metabolites such as quinolinic acid. These metabolites circulate systemically or are released locally in the brain and can contribute to the excitotoxic death of oligodendrocytes and neurons in neurological disease principally by virtue of their agonist activity at N-methyl-d-aspartic acid receptors. The latest evidence is presented and discussed. The enzymes that control the checkpoints in the KP represent an attractive therapeutic target, and consequently several KP inhibitors are currently in clinical trials for other neurological diseases, and hence may make suitable candidates for MS patients. Underpinning these drug discovery endeavors, in recent years, several advances have been made in how KP metabolites are assayed in various biological fluids, and tremendous advancements have been made in how specimens are imaged to determine disease progression and involvement of various cell types and molecules in MS.

Leuprolide Acetate Inhibits Spinal Cord Inflammatory Response in Experimental Autoimmune Encephalomyelitis by Suppressing NF-κB Activation

OBJECTIVE

Recent findings have shown that gonadotropin-releasing hormone (GnRH) administration in an animal model of multiple sclerosis (experimental autoimmune encephalomyelitis, EAE) improves clinical signs of locomotion. The present study was designed to determine whether the administration of the synthetic analog of GnRH, leuprolide acetate (LA) - besides its effects on clinical signs of locomotion - also has an effect on the activation/expression levels of molecular markers of EAE, namely transcription nuclear factor (NF)-κB and the proinflammatory cytokines IL-1β, IL-17A, IL-23 and TNF-α.

METHODS

EAE spinal cords were collected from control and LA-administered rats. Lumbar sections were processed at four different time points during the course of the disease to analyze NF-κB activation by chemiluminescent Western blot, and during the EAE recovery phase to evaluate proinflammatory cytokine levels by quantitative real-time PCR.

RESULTS

It was found that LA administration to EAE rats promoted a significant reduction of NF-κB activation during the course of the disease and also decreased the mRNA expression levels of the proinflammatory cytokines IL-1β, IL-17A and TNF-α in the EAE recovery phase; both effects are consistent with the decrease in the severity of clinical signs of locomotion induced by the treatment.

CONCLUSION

LA causes a reduction in the severity of locomotor activity, as well as in the activation of NF-κB and the number of proinflammatory markers in rats with EAE. These results suggest the use of this agonist as a potential therapeutic approach for multiple sclerosis.

Immune and Epstein-Barr virus gene expression in cerebrospinal fluid and peripheral blood mononuclear cells from patients with relapsing-remitting multiple sclerosis

Background

Gene expression analyses in paired cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) from patients with multiple sclerosis (MS) are restrained by the low RNA amounts from CSF cells and low expression levels of certain genes. Here, we applied a Taqman-based pre-amplification real-time reverse-transcription polymerase chain reaction (RT-PCR) (PreAmp RT-PCR) to cDNA from CSF cells and PBMC of MS patients and analyzed multiple genes related to immune system function and genes expressed by Epstein-Barr virus (EBV), a herpesvirus showing strong association with MS. Using this enhanced RT-PCR method, we aimed at the following: (1) identifying gene signatures potentially useful for patient stratification, (2) understanding whether EBV infection is perturbed in CSF and/or blood, and (3) finding a link between immune and EBV infection status.

Methods

Thirty-one therapy-free patients with relapsing-remitting MS were included in the study. Paired CSF cells and PBMC were collected and expression of 41 immune-related cellular genes and 7 EBV genes associated with latent or lytic viral infection were determined by PreAmp RT-PCR. Clinical, radiological, CSF, and gene expression data were analyzed using univariate and multivariate (cluster analysis, factor analysis) statistical approaches.

Results

Several immune-related genes were differentially expressed between CSF cells and PBMC from the whole MS cohort. By univariate analysis, no or only minor differences in gene expression were found associated with sex, clinical, or radiological condition. Cluster analysis on CSF gene expression data grouped patients into three clusters; clusters 1 and 2 differed by expression of genes that are related mainly to innate immunity, irrespective of sex and disease characteristics. By factor analysis, two factors grouping genes involved in antiviral immunity and immune regulation, respectively, accurately discriminated cluster 1 and cluster 2 patients. Despite the use of an enhanced RT-PCR method, EBV transcripts were detected in a minority of patients (5 of 31), with evidence of viral latency activation in CSF cells or PBMC and of lytic infection in one patient with active disease only.

Conclusions

Analysis of multiple cellular and EBV genes in paired CSF cell and PBMC samples using PreAmp RT-PCR may yield new information on the complex interplay between biological processes underlying MS and help in biomarker identification.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0353-1) contains supplementary material, which is available to authorized users.

Flow cytometric analysis of T cell/monocyte ratio in clinically isolated syndrome identifies patients at risk of rapid disease progression

Background:

Multiple sclerosis is a chronic inflammatory central nervous system disease diagnosed by clinical presentation and characteristic magnetic resonance imaging findings. The role of cerebrospinal fluid (CSF) analysis has been emphasized in particular in the context of differential diagnosis in patients with a first episode suggestive of multiple sclerosis.

Objective:

We investigated here the potential additional value of analysis of CSF cellularity by fluorescence activated cell sorting (FACS) in the setting of a routine diagnostic work-up in our inpatient clinic.

Methods:

CSF cells from back-up samples from patients with suspected chronic inflammatory central nervous system disorder were analyzed by FACS and correlated with clinical data, magnetic resonance imaging findings and oligoclonal band status.

Results:

We found distinct changes of T cell/monocyte (CD4/CD14) and B cell/monocyte (CD20/CD14) ratios between clinically isolated syndrome (CIS)/multiple sclerosis and other neurologic diseases or other inflammatory neurologic diseases. In particular, patients with a rapid transition from CIS to multiple sclerosis had an elevated CD4/CD14 ratio. A subgroup analysis showed diagnostic value of CD4/CD8 ratio in the differential diagnosis of CIS/multiple sclerosis to neurosarcoidosis.

Conclusion:

The diagnostic and prognostic accuracy of autoimmune neuroinflammatory diseases can be improved by FACS analysis of CSF cells.

Natalizumab analogon therapy is effective in a B cell-dependent multiple sclerosis model

AIMS

Natalizumab is a humanized monoclonal antibody specific for CD49d receptors of integrins. It inhibits the entry of inflammatory cells into the central nervous system and is approved for the treatment of relapsing-remitting multiple sclerosis (MS). Several lines of evidence indicate an involvement of B cells and plasma cells in MS pathogenesis. However, treatment with the natalizumab analogon PS/2 immunoglobulin G (IgG) has so far only been investigated in T cell-mediated animal models of MS. Due to the importance of B lineage cells in the pathogenesis of MS, the objective of the present study has thus been to analyse the effects of PS/2 IgG in a mouse model of MS with T and B cell cooperation (OSE mice).

METHODS

OSE mice were treated with the natalizumab analogon PS/2 IgG either at disease onset or after peak of disease. Treatment was also performed with PS/2 F(ab')2 fragments.

RESULTS

PS/2 IgG treatment improved the clinical outcome and decreased spinal cord demyelination and immune cell infiltration if given early in the disease course. Treatment increased blood leukocytes and resulted in a partial internalization of CD49d in T and B cells. The therapeutic effects of PS/2 IgG injections were independent of the Fc fragment as F(ab')2 injections were equally beneficial. In contrast, PS/2 IgG was not effective when given late in the disease course.

CONCLUSIONS

Results indicate that natalizumab may also be beneficial in MS with B cell-driven immunopathogenesis.

Cerebrospinal fluid CXCL13 in clinically isolated syndrome patients: Association with oligoclonal IgM bands and prediction of Multiple Sclerosis diagnosis

Cerebrospinal fluid (CSF) CXCL13 was shown to correlate with markers of intrathecal inflammation and CSF oligoclonal IgM bands (IgMOB) have been associated with a more severe Multiple Sclerosis (MS) course. We correlated CSF CXCL13 levels with clinical, MRI and CSF parameters, including CSF IgMOB, in 110 Clinically Isolated Syndrome (CIS) patients. CSF CXCL13 levels correlated with CSF cell count, total protein, IgG Index and with the presence of CSF IgGOB and IgMOB. CSF CXCL13 levels ≥15.4 pg/ml showed a good positive predictive value and specificity for a MS diagnosis and for a clinical relapse within one year from onset.

Street-experienced peripheral B cells traffic to the brain

Deep sequencing of immunoglobulin repertoires in multiple sclerosis patients reveals dysregulation of peripheral B cell immunity (Palanichamy et al. and Stern et al., this issue).

Intrathecal IgG synthesis: a resistant and valuable target for future multiple sclerosis treatments

Intrathecal IgG synthesis is a key biological feature of multiple sclerosis (MS). When acquired early, it persists over time. A growing body of evidence suggests that intrathecal Ig-secreting cells may be pathogenic either by a direct action of toxic IgG or by locally secreting bystander toxic products. Intrathecal IgG synthesis depends on the presence of CNS lymphoid organs, which are strongly linked at anatomical level to cortical subpial lesions and at clinical level to the impairment slope in progressive MS. As a consequence, targeting CNS lymphoid lesions could be a valuable new target in MS, especially during the progressive phase. As intrathecal IgGs are end-products of these lymphoid lesions, intrathecal IgG synthesis may be considered as a specific marker of the persistence of these inflammatory lesions. Here we review the effect upon intrathecal IgG synthesis of all drugs ever used in MS. Except for steroids, all these therapeutic strategies, including rituximab, failed to decrease intrathecal IgG synthesis, with the exception of a questionable incomplete action of natalizumab. Thus, IgG synthesis is a robust marker of persistent intrathecal inflammation and its complete normalization should be one of the goals in future therapeutic strategies.

[Meningeal tertiary lymphoid organs: Major actors in intrathecal autoimmunity]

Multiple sclerosis (MS) is characterized by an intrathecal synthesis of immunoglobulins synthesized by B-cell clones and by a brain infiltrate of clonal T-cells. The clonal maturation of these lymphocytes takes place in tertiary lymphoid organs (TLO) developed in the intrathecal compartment. TLO are acquired lymphoid organs able to develop in the vicinity of the inflammatory sites, where they mount a complete antigen-driven immune response. We here review TLO pathophysiology in animal models of MS and human MS. Several pieces of evidence suggest that intrathecal TLO may play a major role in the clinical impairment. Potential therapeutic applications are examined.

Decreased Dicer expression is linked to increased expression of co-stimulatory molecule CD80 on B cells in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated inflammatory disease of the central nervous system. B cells have been strongly implicated in disease pathogenesis based on clinical trials with B-cell ablation. There is a growing body of evidence linking microRNAs with regulation of the immune system. Dicer, a key enzyme involved in microRNA biogenesis, is necessary for normal B-cell function.

OBJECTIVE

We aimed to determine whether Dicer expression is impaired in B cells and is linked to increased expression co-stimulatory molecules in patients with MS.

METHODS

B cells were separated from blood samples of MS patients and healthy subjects. Expression of Dicer and co-stimulatory molecules CD80 and CD86 was tested. The effect of Dicer modulation on CD80 and CD86 expression in B cells was studied.

RESULTS

Dicer expression was decreased in B cells but not in monocytes of patients with MS compared with healthy subjects. CD80 and CD86 expression was increased on B cells of MS patients compared with healthy subjects. Inhibition of Dicer expression in B cells by small interfering RNA led to increased expression of CD80.

CONCLUSION

Dicer expression is decreased and is mechanistically linked to increased expression of co-stimulatory molecule CD80 in B cells of patients with MS. This may contribute to activation of immune responses in MS.

A new risk variant for multiple sclerosis at the immunoglobulin heavy chain locus associates with intrathecal IgG, IgM index and oligoclonal bands

Background:

Recent findings have shown a correlation between the intrathecal IgG index and variants at the immunoglobulin heavy chain (IGHC) locus in patients with multiple sclerosis (MS).

Objectives:

The objective of this paper is to analyse the association of the locus with MS susceptibility and its relationship with intrathecal immunoglobulin (Ig) parameters.

Methods:

We genotyped the rs11621145 variant, located at the IGHC locus, in 2726 patients with MS and 2133 healthy controls. Associations of intrathecal IgG and IgM indexes with rs11621145 were analysed by linear regression analysis in 538 MS patients.

Results:

We found that rs11621145 showed statistically significant evidence for association with susceptibility to MS (odds ratio = 0.69, p = 1.053E-09), though validation of this result in additional cohorts would be desirable. We confirmed the association between the IgG index and the rs11621145 ( p = 6.85E-07, Beta = 0.207). Furthermore, rs11621145 was inversely correlated with IgM index ( p = 7.24E-04, Beta = -0.277), and therefore marks a decreased likelihood of presenting IgM oligoclonal bands (odds ratio = 0.38, p = 2.35E-06).

Conclusions:

Our results suggest that the polymorphism of the IGHC locus could be altering the switching of the Ig isotype in B cells and it may be interfering with T-dependent and T-independent antibody responses.

MMP-9 expression is increased in B lymphocytes during multiple sclerosis exacerbation and is regulated by microRNA-320a

B cells are necessary to maintain disease activity in relapsing multiple sclerosis (MS) and produce matrix metallopeptidase-9 (MMP-9), which disrupts the blood-brain barrier. MMP-9 protein expression was increased and expression of microRNA-320a (miR-320a), which targets MMP-9 mRNA, was significantly decreased in B lymphocytes of MS patients during a disease relapse compared to remission. Functional significance of these findings was demonstrated by transfecting human B lymphocytes with miR-320a inhibitor, which led to increased MMP-9 expression and secretion. In summary, expression of miR-320a is decreased in B cells of MS patients and may contribute to increased blood-brain barrier permeability and neurological disability.

Cerebrospinal fluid immunological biomarkers associated with axonal damage in multiple sclerosis

BACKGROUND AND PURPOSE

Cerebrospinal fluid (CSF) neurofilament light protein (NFL) is a promising biomarker of axonal injury and neurodegeneration. Here CSF lymphocyte subpopulations and antibodies, potential players of neurodegeneration, are examined in relation to CSF NFL shedding in MS.

METHODS

Cerebrospinal fluid NFL from 127 consecutive untreated MS patients was analysed. Samples from 37 age-matched patients with other central nervous system non-inflammatory neurological diseases (NIND) were also assessed. CD4+, CD8+, CD56+ and CD19+ cell subsets were studied by flow cytometry. Oligoclonal IgG and IgM bands (OCMB) against lipids were studied by isoelectric focusing and immunoblotting. These data were analysed in relation to clinical and magnetic resonance imaging features.

RESULTS

A CSF NFL cut-off value of 900 ng/l (mean + 3 SD of NIND values) was calculated. MS patients with increased NFL values showed significantly higher Multiple Sclerosis Severity Score and magnetic resonance imaging lesion number. The presence of OCMB (P < 0.0001) and elevated T and B lymphocyte counts was associated with increased levels of CSF NFL.

CONCLUSIONS

High CSF NFL levels are associated with elevated CSF lymphocyte cell counts and intrathecal synthesis of IgM against lipids. These findings support a role for OCMB in the axonal damage of MS offering a rationale for the association of these antibodies with disability and brain atrophy progression in MS.