Glatiramer acetate attenuates the pro-migratory profile of adhesion molecules on various immune cell subsets in multiple sclerosis

The role of NK and NKT cells in the pathogenesis and improvement of multiple sclerosis following disease‐modifying therapies

Background

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS) that T cells become autoreactive by recognizing CNS antigens. Both innate and adaptive immune systems are involved in the pathogenesis of MS. In recent years, the impact of innate immune cells on MS pathogenesis has received more attention. CD56^bright NK cells, as an immunoregulatory subset of NK cells, can increase the production of cytokines that modulate adaptive immune responses, whereas CD56^dim NK cells are more active in cytolysis functions. These two main subsets of NK cells may have different effects on the onset or progression of MS. Invariant NKT (iNKT) cells are other immune cells involved in the control of autoimmune diseases; however, variant NKT (vNKT) cells, despite limited information, could play a role in MS remission via an immunoregulatory pathway.

Aim

We aimed to evaluate the influence of MS therapeutic agents on NK and NKT cells and NK cell subtypes.

Materials and Methods

The possible mechanism of each MS therapeutic agent has been presented here, focusing on the effects of different disease‐modifying therapies on the number of NK and NKT subtypes.

Results

Expansion of CD56^bright NK cells, reduction in the CD56^dim cells, and enhancement in NKT cells are the more important innate immune cells alterations following the disease‐modifying therapies.

Conclusion

Expansion of CD56^bright NK cells or reduction in the CD56^dim cells has been associated with a successful response to different treatments in MS. iNKT and vNKT cells could have beneficial effects on MS improving. It seems that they are enhanced due to some of MS drugs, leading to disease improvement. However, a reduction in the number of NKT cells could be due to the adverse effects of some of MS drugs on the bone marrow.

Cladribine Alters Immune Cell Surface Molecules for Adhesion and Costimulation: Further Insights to the Mode of Action in Multiple Sclerosis

Cladribine (CLAD) is a deoxyadenosine analogue prodrug which is given in multiple sclerosis (MS) as two short oral treatment courses 12 months apart. Reconstitution of adaptive immune function following selective immune cell depletion is the presumed mode of action. In this exploratory study, we investigated the impact of CLAD tablets on immune cell surface molecules for adhesion (CAMs) and costimulation (CoSs) in people with MS (pwMS). We studied 18 pwMS who started treatment with CLAD and 10 healthy controls (HCs). Peripheral blood mononuclear cells were collected at baseline and every 3 months throughout a 24-month period. We analysed ICAM-1, LFA-1, CD28, HLADR, CD154, CD44, VLA-4 (CD49d/CD29), PSGL-1 and PD-1 with regard to their expression on B and T cells (T helper (Th) and cytotoxic T cells (cT)) and surface density (mean fluorescence intensity, MFI) by flow cytometry. The targeted analysis of CAM and CoS on the surface of immune cells in pwMS revealed a higher percentage of ICAM-1 (B cells, Th, cT), LFA-1 (B cells, cT), HLADR (B cells, cT), CD28 (cT) and CD154 (Th). In pwMS, we found lower frequencies of Th and cT cells expressing PSGL-1 and B cells for the inhibitory signal PD-1, whereas the surface expression of LFA-1 on cT and of HLADR on B cells was denser. Twenty-four months after the first CLAD cycle, the frequencies of B cells expressing CD44, CD29 and CD49d were lower compared with the baseline, together with decreased densities of ICAM-1, CD44 and HLADR. The rate of CD154 expressing Th cells dropped at 12 months. For cT, no changes were seen for frequency or density. Immune reconstitution by oral CLAD was associated with modification of the pro-migratory and -inflammatory surface patterns of CAMs and CoSs in immune cell subsets. This observation pertains primarily to B cells, which are key cells underlying MS pathogenesis.

NKT and NKT-like Cells in Autoimmune Neuroinflammatory Diseases-Multiple Sclerosis, Myasthenia Gravis and Guillain-Barre Syndrome

NKT cells comprise three subsets—type I (invariant, iNKT), type II, and NKT-like cells, of which iNKT cells are the most studied subset. They are capable of rapid cytokine production after the initial stimulus, thus they may be important for polarisation of Th cells. Due to this, they may be an important cell subset in autoimmune diseases. In the current review, we are summarising results of NKT-oriented studies in major neurological autoimmune diseases—multiple sclerosis, myasthenia gravis, and Guillain-Barre syndrome and their corresponding animal models.

Baseline and overtime variations of soluble adhesion molecule plasma concentrations are associated with mobility recovery after rehabilitation in multiple sclerosis patients

Rehabilitative exercise outcomes and plasma concentrations of soluble adhesion molecules (sEndoglin, sE-Selectin, sL-Selectin, sICAM-1, sNCAM, sNCAM-1, sVCAM-1, sPECAM-1, sVAP-1) were evaluated in 60 severely disabled progressive multiple sclerosis (MS) patients at 4-time points. Changes of sE-Selectin, sL-Selectin, and sPECAM-1 concentrations were observed over time, and their variations were significantly correlated with rehabilitative outcome variations. Baseline sVAP-1 concentrations were able to predict functional mobility recovery. Our data suggest that the evaluation of adhesion molecules in plasma provides useful information to interpret rehabilitative exercise processes and to identify potential predictors of the rehabilitation-induced changes in mobility outcomes in MS patients.

The role of B cells in the immunopathogenesis of multiple sclerosis

There is ongoing debate on how B cells contribute to the pathogenesis of multiple sclerosis (MS). The success of B-cell targeting therapies in MS highlighted the role of B cells, particularly the antibody-independent functions of these cells such as antigen presentation to T cells and modulation of the function of T cells and myeloid cells by secreting pathogenic and/or protective cytokines in the central nervous system. Here, we discuss the role of different antibody-dependent and antibody-independent functions of B cells in MS disease activity and progression proposing new therapeutic strategies for the optimization of B-cell targeting treatments.

Glatiramer acetate protects against oxygen-glucose deprivation/reperfusion-induced injury by inhibiting Egr-1 in H9c2 cells

Myocardial infarction (MI) or heart attack is a deadly event with high prevalence. In the present study, we investigated the effects of the polypeptide copolymer glatiramer acetate (GA) in H9c2 rat cardiomyocytes exposed to oxygen-glucose deprivation/reperfusion injury. Immediately following MI, an acute inflammatory response is triggered that causes activation of various proinflammatory cytokines, infiltration of immune cells, and neovascularization. This response is largely mediated by some genes such as TNF-α, IL-6, ICAM-1, and VEGF. Additionally, the rapid influx of oxidants, such as reactive oxygen species (ROS), leads to a harmful state of oxidative stress. Here, we found that GA could reduce OGD/R-induced inflammation and oxidative stress by inhibiting the expression of TNF-α, IL-6, ICAM-1, and VEGF, and suppressing the production of ROS via reduced NADPH oxidase 1 (NOX1) expression. To elucidate the pathways involved in these promising results, we took a close look at the impact of the endothelial growth response-1 (Egr-1), a transcriptional factor recognized as a mediator of MI-related inflammation and cellular injury. Using siRNA for Egr-1, we found that GA could reduce the expression of ICAM-1 and VEGF by inhibiting Egr-1 expression. Together, our findings indicate a novel therapeutic potential of GA in the treatment of MI.

B Cell-based Therapies for Multiple Sclerosis

The traditional view of multiple sclerosis (MS) as a T cell mediated autoimmune disease of the central nervous system (CNS) has evolved into a concept of an immune-mediated disease where complex bi-directional interactions between T cells, B cells and myeloid cells underlie and shape CNS-directed autoimmunity. B cells are now recognized as major contributors to the pathogenesis of MS, largely due to increased understanding of their biology and the profound anti-inflammatory effects demonstrated by B cell depletion in MS. In this chapter we discuss the fundamental roles B cells play in the pathogenesis of MS and review current and future therapeutic strategies targeting B cells in MS, including B cell depletion with various monoclonal antibodies (mAbs) against the B cell surface markers CD20 and CD19, anti-B cell cytokine therapies, blocking Bruton's tyrosine kinase (BTK) in B cells, and various immunomodulatory and immunosuppressive effects exerted on B cells by virtually all other approved therapies for MS.

Shared Gene Expression Between Multiple Sclerosis and Ischemic Stroke

Patients with multiple sclerosis (MS) appear to have an increased risk of ischemic stroke (IS). Although MS and IS have very different phenotypes, gene-based and pathway-based analyses of large-scale genome-wide association studies (GWAS) have increasingly enhanced our understanding of these two diseases. Whether there are common molecular mechanisms connecting MS and IS is still unclear. Here, we describe the outcome of gene-based test and pathway-based analysis of GWAS datasets that explored potential gene expression links between MS and IS. After identifying significant gene sets individually of MS and IS, we performed pathway-based analysis in four biological pathway databases (KEGG, PANTHER, REACTOME, and WikiPathways) and GO categories. We discovered that there were 9 shared pathways between MS and IS in KEGG, 2 in PANTHER, 14 in REACTOME, 1 in WikiPathways, and 194 in GO annotations (p < 0.05). These results provide an improved understanding about possible shared mechanisms and treatments strategies for MS and IS. They also provide some basis for further studies of how these two diseases are linked at the molecular level.

Circulating EZH2-positive T cells are decreased in multiple sclerosis patients

BACKGROUND

Recent studies in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), suggest an involvement of the histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) in important processes such as cell adhesion and migration.

METHODS

Here, we aimed to expand these initial observations by investigating the role of EZH2 in MS. mRNA expression levels for EZH2 were measured by real-time PCR in peripheral blood mononuclear cells (PBMC) from 121 MS patients (62 untreated and 59 receiving treatment) and 24 healthy controls.

RESULTS

EZH2 expression levels were decreased in PBMC from untreated patients compared to that from controls, and treatment significantly upregulated EZH2 expression. Expression of miR-124 was increased in MS patients compared to controls. Blood immunophenotyping revealed EZH2 expression mostly restricted to CD4+ and CD8+ T cells, and circulating EZH2+ CD4+ and CD8+ T cells were decreased in untreated MS patients compared to controls. CD8+ T cells expressing EZH2 exhibited a predominant central memory phenotype, whereas EZH2+ CD4+ T cells were of effector memory nature, and both T cell subsets produced TNF-α. EZH2+ T cells were enriched in the cerebrospinal fluid compartment compared to blood and were found in chronic active lesions from MS patients. EZH2 inhibition and microarray analysis in PBMC was associated with significant downregulation of key T cell adhesion molecules.

CONCLUSION

These findings suggest a role of EZH2 in the migration of T cells in MS patients. The observation of TNF-α expression by CD4+ and CD8+ T cells expressing EZH2 warrants additional studies to explore more in depth the pathogenic potential of EZH2+-positive cells in MS.

The role of B cells in multiple sclerosis: Current and future therapies

While it was long held that T cells were the primary mediators of multiple sclerosis (MS) pathogenesis, the beneficial effects observed in response to treatment with Rituximab (RTX), a monoclonal antibody (mAb) targeting CD20, shed light on a key contributor to MS that had been previously underappreciated: B cells. This has been reaffirmed by results from clinical trials testing the efficacy of subsequently developed B cell-depleting mAbs targeting CD20 as well as studies revisiting the effects of previous disease-modifying therapies (DMTs) on B cell subsets thought to modulate disease severity. In this review, we summarize current knowledge regarding the complex roles of B cells in MS pathogenesis and current and potential future B cell-directed therapies.

Reassessing B cell contributions in multiple sclerosis

There is growing recognition that B cell contributions to normal immune responses extend well beyond their potential to become antibody-producing cells, including roles at the innate-adaptive interface and their potential to modulate the responses of other immune cells such as T cells and myeloid cells. These B cell functions can have both pathogenic and protective effects in the context of central nervous system (CNS) inflammation. Here, we review recent advances in the field of multiple sclerosis (MS), which has traditionally been viewed as primarily a T cell-mediated disease, and we consider antibody-dependent and, particularly, emerging antibody-independent functions of B cells that may be relevant in both the peripheral and CNS disease compartments.

Impact of Glatiramer Acetate on B Cell-Mediated Pathogenesis of Multiple Sclerosis

Growing evidence indicates that B cells play a key role in the pathogenesis of multiple sclerosis (MS). B cells occupy distinct central nervous system (CNS) compartments in MS, including the cerebrospinal fluid and white matter lesions. Also, it is now known that, in addition to entering the CNS, B cells can circulate into the periphery via a functional lymphatic system. Data suggest that the role of B cells in MS mainly involves their in situ activation in demyelinating lesions, leading to altered pro- and anti-inflammatory cytokine secretion, and a highly effective antigen-presenting cell function, resulting in activation of memory or naïve T cells. Clinically, B cell-depleting agents show significant efficacy in MS. In addition, many disease-modifying therapies (DMTs) traditionally understood to target T cells are now known to influence B cell number and function. One of the earliest DMTs to be developed, glatiramer acetate (GA), has been shown to reduce the total frequency of B cells, plasmablasts, and memory B cells. It also appears to promote a shift toward reduced inflammation by increasing anti-inflammatory cytokine release and/or reducing pro-inflammatory cytokine release by B cells. In the authors' opinion, this may be mediated by cross-reactivity of B cell receptors for GA with antigen (possibly myelin basic protein) expressed in the MS lesion. More research is required to further characterize the role of B cells and their bidirectional trafficking in the pathogenesis of MS. This may uncover novel targets for MS treatments and facilitate the development of B cell biomarkers of drug response.

The contribution of the acute phase response to the pathogenesis of relapse in chronic-relapsing experimental autoimmune encephalitis models of multiple sclerosis

Background

Increased relapse rates in multiple sclerosis (MS) as a consequence of peripheral immune system activation, owing to infection for example, have been widely reported, but the mechanism remains unclear. Acute brain injury models can be exacerbated by augmenting the hepatic acute phase response (APR). Here, we explored the contribution of the hepatic APR to relapse in two rodent models of MS.

Methods

Mice with MOG-CFA-induced chronic relapsing experimental autoimmune encephalitis (CR-EAE) were killed before, during and after the first phase of disease, and the brain and liver chemokine, cytokine and acute phase protein (APP) mRNA expression profile was determined. During remission, the APR was reactivated with an intraperitoneal lipopolysaccharide (LPS) and clinical score was monitored throughout. To explore the downstream mediators, CXCL-1, which is induced as part of the APR, was injected into animals with a focal, cytokine/MOG-induced EAE lesion (fEAE) and the cellularity of the lesions was assessed.

Results

Compared to CFA control, in a rodent CR-EAE model, an hepatic APR preceded clinical signs and central cytokine production in the initial phase of disease. Compared to administration in naïve animals, an LPS challenge during the asymptomatic remission phase of CR-EAE rodents provoked relapse and resulted in the increased and extended expression of specific peripheral hepatic chemokines. CXCL-1 and several other APPs were markedly elevated. A single intravenous administration of the highly induced chemokine, CXCL-1, was found to be sufficient to reactivate the lesions by increasing microglial activation and the recruitment of T cells in fEAE lesions.

Conclusions

The APR plays a contributing role to the pathology seen in models of chronic brain injury and in translating the effects of peripheral immune system stimulation secondary to trauma or infection into central pathology and behavioural signs. Further elucidation of the exact mechanisms in this process will inform development of more effective, selective therapies in MS that, by suppressing the hepatic chemokine response, may prevent relapse.

Deciphering the Role of B Cells in Multiple Sclerosis-Towards Specific Targeting of Pathogenic Function

B cells, plasma cells and antibodies may play a key role in the pathogenesis of multiple sclerosis (MS). This notion is supported by various immunological changes observed in MS patients, such as activation and pro-inflammatory differentiation of peripheral blood B cells, the persistence of clonally expanded plasma cells producing immunoglobulins in the cerebrospinal fluid, as well as the composition of inflammatory central nervous system lesions frequently containing co-localizing antibody depositions and activated complement. In recent years, the perception of a respective pathophysiological B cell involvement was vividly promoted by the empirical success of anti-CD20-mediated B cell depletion in clinical trials; based on these findings, the first monoclonal anti-CD20 antibody—ocrelizumab—is currently in the process of being approved for treatment of MS. In this review, we summarize the current knowledge on the role of B cells, plasma cells and antibodies in MS and elucidate how approved and future treatments, first and foremost anti-CD20 antibodies, therapeutically modify these B cell components. We will furthermore describe regulatory functions of B cells in MS and discuss how the evolving knowledge of these therapeutically desirable B cell properties can be harnessed to improve future safety and efficacy of B cell-directed therapy in MS.

Effector and regulatory B cells in Multiple Sclerosis

The role of B cells in the pathogenesis of Multiple Sclerosis (MS), an autoimmune neurodegenerative disease, is becoming eminent in recent years, but the specific contribution of the distinct B cell subsets remains to be elucidated. Several B cell subsets have shown regulatory, anti-inflammatory capacities in response to stimuli in vitro, as well as in the animal model of MS: Experimental Autoimmune Encephalomyelitis (EAE). However, the functional role of the B regulatory cells (Bregs) in vivo and specifically in the human disease is yet to be clarified. In the present review, we have summarized the updated information on the roles of effector and regulatory B cells in MS and the immune-modulatory effects of MS therapeutic agents on their phenotype and function.

B Cell-Directed Therapeutics in Multiple Sclerosis: Rationale and Clinical Evidence

Over the last decade, evidence condensed that B cells, B cell-derived plasma cells and antibodies play a key role in the pathogenesis and progression of multiple sclerosis (MS). In many patients with MS, peripheral B cells show signs of chronic activation; within the cerebrospinal fluid clonally expanded plasma cells produce oligoclonal immunoglobulins, which remain a hallmark diagnostic finding. Confirming the clinical relevance of these immunological alterations, recent trials testing anti-CD20-mediated depletion of peripheral B cells showed an instantaneous halt in development of new central nervous system lesions and occurrence of relapses. Notwithstanding this enormous success, not all B cells or B cell subsets may contribute in a pathogenic manner, and may, in contrast, exert anti-inflammatory and, thus, therapeutically desirable properties in MS. Naïve B cells, in MS patients similar to healthy controls, are a relevant source of regulatory cytokines such as interleukin-10, which dampens the activity of other immune cells and promotes recovery from acute disease flares in experimental MS models. In this review, we describe in detail pathogenic but also regulatory properties of B and plasma cells in the context of MS and its animal model experimental autoimmune encephalomyelitis. In the second part, we review what impact current and future therapies may have on these B cell properties. Within this section, we focus on the highly encouraging data on anti-CD20 antibodies as future therapy for MS. Lastly, we discuss how B cell-directed therapy in MS could be possibly advanced even further in regard to efficacy and safety by integrating the emerging information on B cell regulation in MS into future therapeutic strategies.

Early hematopoiesis in multiple sclerosis patients

Contemporary evidence supports that MS immunopathology starts in the peripheral lymphatic system. However, the site and character of crucial initiating events are unknown. We examined subsets of the first stages of blood cells in the bone marrow of 9 MS patients and 11 neurologically healthy controls using FACS analysis. The proportion of natural killer T cells was lower (P=0.045) in the bone marrow of MS patients, but proportions of hematogenous stem cells, myeloblasts, and B cell precursor subsets in the bone marrow did not differ between MS patients and controls. In this pilot study with a limited number of samples we found no deviation of the early B cell lineage in bone marrow from MS patients.

Pilot Study of Natural Killer Cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Multiple Sclerosis

Patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and multiple sclerosis (MS) suffer from debilitating fatigue which is not alleviated by rest. In addition to the fatigue-related symptoms suffered by patients with CFS/ME and MS, dysfunction of the immune system and, in particular, reduced natural killer (NK) cell cytotoxic activity has also been reported in CFS/ME and MS. The purpose of this pilot study was to compare NK cellular mechanisms in patients with CFS/ME and MS to investigate potential dysfunctions in the NK cell activity pathway. Flow cytometry protocols assessed CD56(dim) CD16(+) and CD56(bright) CD16(+/-) NK cell expression of adhesion molecules, NK activating and inhibiting receptors, NK cell maturation and lytic proteins. All participants in this study were female and included 14 patients with CFS/ME, nine patients with MS and 19 non-fatigued controls. The patient groups and the non-fatigued controls were not taking any immunosuppressive or immune-enhancing medications. In the MS cohort, KIR2DL5 was significantly increased on CD56(bright) CD16(+/-) NK cells and expression of CD94 was significantly increased on CD56(dim) CD16(+) NK cells in comparison with the controls. Co-expression of CD57 and perforin was significantly increased on CD56(dim) CD16(+) NK cells from patients with CFS/ME compared to the MS and non-fatigued control participants. The results from this pilot study suggest that NK cells from patients with CFS/ME and MS may have undergone increased differentiation in response to external stimuli which may affect different mechanisms in the NK cell cytotoxic activity pathway.

B Cells Are Multifunctional Players in Multiple Sclerosis Pathogenesis: Insights from Therapeutic Interventions

Multiple sclerosis (MS) is a severe disease of the central nervous system (CNS) characterized by autoimmune inflammation and neurodegeneration. Historically, damage to the CNS was thought to be mediated predominantly by activated pro-inflammatory T cells. B cell involvement in the pathogenesis of MS was solely attributed to autoantibody production. The first clues for the involvement of antibody-independent B cell functions in MS pathology came from positive results in clinical trials of the B cell-depleting treatment rituximab in patients with relapsing-remitting (RR) MS. The survival of antibody-secreting plasma cells and decrease in T cell numbers indicated the importance of other B cell functions in MS such as antigen presentation, costimulation, and cytokine production. Rituximab provided us with an example of how clinical trials can lead to new research opportunities concerning B cell biology. Moreover, analysis of the antibody-independent B cell functions in MS has gained interest since these trials. Limited information is present on the effects of current immunomodulatory therapies on B cell functions, although effects of both first-line (interferon, glatiramer acetate, dimethyl fumarate, and teriflunomide), second-line (fingolimod, natalizumab), and even third-line (monoclonal antibody therapies) treatments on B cell subtype distribution, expression of functional surface markers, and secretion of different cytokines by B cells have been studied to some extent. In this review, we summarize the effects of different MS-related treatments on B cell functions that have been described up to now in order to find new research opportunities and contribute to the understanding of the pathogenesis of MS.

Gene expression studies of a human monocyte cell line identify dissimilarities between differently manufactured glatiramoids

Glatiramer Acetate (GA) has provided safe and effective treatment for multiple sclerosis (MS) patients for two decades. It acts as an antigen, yet the precise mechanism of action remains to be fully elucidated, and no validated pharmacokinetic or pharmacodynamic biomarkers exist. In order to better characterize GA’s biological impact, genome-wide expression studies were conducted with a human monocyte (THP-1) cell line. Consistent with previous literature, branded GA upregulated anti-inflammatory markers (e.g. IL10), and modulated multiple immune-related pathways. Despite some similarities, significant differences were observed between expression profiles induced by branded GA and Probioglat, a differently-manufactured glatiramoid purported to be a generic GA. Key results were verified using qRT-PCR. Genes (e.g. CCL5, adj. p < 4.1 × 10⁻⁵) critically involved in pro-inflammatory pathways (e.g. response to lipopolysaccharide, adj. p = 8.7 × 10⁻⁴) were significantly induced by Probioglat compared with branded GA. Key genes were also tested and confirmed at the protein level, and in primary human monocytes. These observations suggest differential biological impact by the two glatiramoids and warrant further investigation.

High interindividual variability in the CD4/CD8 T cell ratio and natalizumab concentration levels in the cerebrospinal fluid of patients with multiple sclerosis

Strongly decreased leucocyte counts and a reduced CD4/CD8 T cell ratio in the cerebrospinal fluid (CSF) of natalizumab (NZB)-treated multiple sclerosis (MS) patients may have implications on central nervous (CNS) immune surveillance. With regard to NZB-associated progressive multi-focal leucoencephalopathy, we aimed at delineating a relationship between free NZB, cell-bound NZB, adhesion molecule (AM) expression and the treatment-associated shift in the CSF T cell ratio. Peripheral blood (PB) and CSF T cells from 15 NZB-treated MS patients, and CSF T cells from 10 patients with non-inflammatory neurological diseases and five newly diagnosed MS patients were studied. Intercellular adhesion molecule-1 (ICAM-1), leucocyte function antigen-1 (LFA-1), very late activation antigen-4 (VLA-4), NZB saturation levels, and T cell ratios were analysed by flow cytometry. NZB concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Lower NZB saturation levels (P<0.02) and a higher surface expression of ICAM-1 and LFA-1 (P<0.001) were observed on CSF CD8 T cells. CSF T cell ratios (0.3-2.1) and NZB concentrations (0.01-0.42 µg/ml) showed a pronounced interindividual variance. A correlation between free NZB, cell-bound NZB or AM expression levels and the CSF T cell ratio was not found. Extremely low NZB concentrations and a normalized CSF T cell ratio were observed in one case. The differential NZB saturation and AM expression of CSF CD8 T cells may contribute to their relative enrichment in the CSF. The reduced CSF T cell ratio appeared sensitive to steady-state NZB levels, as normalization occurred quickly. The latter may be important concerning a fast reconstitution of CNS immune surveillance.

Serum Levels of Biomarkers of Immune Activation and Associations With Neurological Impairment in Relapsing-Remitting Multiple Sclerosis Patients During Remission

INTRODUCTION

Although much is known about cytokines and adhesion molecules during an active course of multiple sclerosis (MS), there is limited information about their serum levels during remission.

OBJECTIVE

This study aimed to (1) compare peripheral levels of tumor necrosis factor-α (TNF-α), soluble interleukin-2 receptor α (sIL-2Rα), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble E-selectin (sE-selectin) in MS patients during clinical remission with those of healthy controls and (2) explore possible relationships between the levels of these cytokines and adhesion molecules and neurological impairment.

METHODS

Initially, 92 patients with relapsing-remitting multiple sclerosis (RRMS) who were in clinical remission and 30 healthy controls were recruited for this study. The severity of neurological impairment was assessed with the Expanded Disability Status Scale (EDSS). Serum concentrations of TNF-α, sIL-2Rα, sICAM-1, and sE-selectin were determined using the sandwich enzyme-linked immunosorbent (ELISA) technique and compared between patients and controls. In a subset of RRMS patients (n = 67), the levels of these cytokines and adhesion molecules were compared between subgroups of patients based on scores on the EDSS subscales, which measure disability level for specific neurological functions.

RESULTS

The MS patients' TNF-α, sICAM-1, and sE-selectin levels were markedly lower than those of the controls, while their sIL-2Rα level was higher. The serum sICAM-1 concentration was positively associated with EDSS total score (ρ = .291, p = .017) as well as with the EDSS pyramidal (ρ = .267, p = .029) and cerebellar subscores (ρ = .303, p = .013). In the patients with cerebellar deficits and severe brain stem dysfunction, sICAM-1 levels were upregulated.

CONCLUSION

Although a decreased sICAM-1 concentration was observed in RRMS patients in remission as compared to healthy controls, sICAM-1 seemed to reflect neurological impairment and clinical disability. These data suggest that increasing serum sICAM-1 levels may be associated with progression of cerebellar or brain stem perturbations. However, further studies are required to confirm these findings in a larger population of RRMS patients.

Immune regulation of multiple sclerosis by CD8+ T cells

The role of CD8+ T cells in the process of autoimmune pathology has been both understudied and controversial. Multiple sclerosis (MS) is an inflammatory, demyelinating disorder of the central nervous system (CNS) with underlying T cell-mediated immunopathology. CD8+ T cells are the predominant T cells in human MS lesions, showing oligoclonal expansion at the site of pathology. It is still unclear whether these cells represent pathogenic immune responses or disease-regulating elements. Through studies in human MS and its animal model, experimental autoimmune encephalomyelitis (EAE), we have discovered two novel CD8+ T cell populations that play an essential immunoregulatory role in disease: (1) MHC class Ia-restricted neuroantigen-specific "autoregulatory" CD8+ T cells and (2) glatiramer acetate (GA/Copaxone(®)) therapy-induced Qa-1/HLA-E-restricted GA-specific CD8+ T cells. These CD8+ Tregs suppress proliferation of pathogenic CD4+ CD25- T cells when stimulated by their cognate antigens. Similarly, CD8+ Tregs significantly suppress EAE when transferred either pre-disease induction or during peak disease. The mechanism of disease inhibition depends, at least in part, on an antigen-specific, contact-dependent process and works through modulation of CD4+ T cell responses as well as antigen-presenting cells through a combination of cytotoxicity and cytokine-mediated modulation. This review provides an overview of our understanding of CD8+ T cells in immune-mediated disease, focusing particularly on our findings regarding regulatory CD8+ T cells both in MS and in EAE. Clinical relevance of these novel CD8-regulatory populations is discussed, providing insights into a potentially intriguing, novel therapeutic strategy for these diseases.

Glatiramer acetate (GA) prevents TNF-α-induced monocyte adhesion to primary endothelial cells through interfering with the NF-κB pathway

Pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) is considered to be the major one contributing to the process of development of endothelial dysfunction. Exposure to TNF-α induces the expression of a number of proinflammatory chemokines, such as monocyte chemotactic protein-1 (MCP-1), and adhesion molecules, including vascular adhesion molecule-1 (VCAM-1) and E-selectin, which mediate the interaction of invading monocytes with vascular endothelial cells. Glatiramer acetate (GA) is a licensed clinical drug for treating patients suffering from multiple sclerosis (MS). The effects of GA in vascular disease have not shown before. In this study, we found that GA significantly inhibited TNF-α-induced binding of monocytes to endothelial cells. Mechanistically, we found that GA ameliorated the upregulation of MCP-1, VCAM-1, and E-selectin induced by TNF-α. Notably, this process is mediated by inhibiting the nuclear translocation and activation of NF-κB. Our results also indicate that GA pretreatment attenuates the up-regulation of COX-2 and iNOS. These data suggest that GA might have a potential benefit in therapeutic endothelial dysfunction related diseases.

Selectins and their ligands as potential immunotherapeutic targets in neurological diseases

Selectins are a family of adhesion receptors that bind to highly glycosylated molecules expressed on the surface of leukocytes and endothelial cells. The interactions between selectins and their ligands control tethering and rolling of leukocytes on the vascular wall during the process of leukocyte migration into the tissues under physiological and pathological conditions. In recent years, it has been shown that leukocyte recruitment in the CNS plays a pivotal role in diseases such as multiple sclerosis, ischemic stroke, epilepsy and traumatic brain injury. In this review, we discuss the role of selectins in leukocyte–endothelial interactions in the pathogenesis of neurological diseases, highlighting new findings suggesting that selectins and their ligands may represent novel potential therapeutic targets for the treatment of CNS diseases.