Treating multiple sclerosis with monoclonal antibodies: a 2013 update

Extracellular vesicles of Bacteroides uniformis induce M1 macrophage polarization and aggravate gut inflammation during weaning

Weaning process is commonly associated with gastrointestinal inflammation and dysbiosis of the intestinal microbes. In particular, the impact of gut bacteria and of extracellular vesicles (EV) on the etiology of intestinal inflammation during weaning is not well understand. We have uncovered a potential link between gut inflammation and the corresponding variation of macrophage bacterial sensing and pro-inflammatory polarization during the weaning process of piglet through single-cell transcriptomic analyses. We conducted a comprehensive analysis of bacterial distribution across the gastrointestinal tract and pinpointed Bacteroides uniformis (B. uniformis) enriching in piglets undergoing weaning. Next, we found out that exposure to B. uniformis-derived EVs (BEVs) exacerbated gut inflammation in a murine colitis model while recruiting and polarizing intestinal macrophages towards a pro-inflammatory phenotype. BEVs modulated the function of macrophages cultured in vitro by suppressing the GM-CSF/STAT5/ARG1 pathway, thereby affecting polarization towards an M1-like state. The effects of BEVs were verified both in the macrophage-clearance murine model and by using an adoptive transfer assay. Our findings highlight the involvement of BEVs in facilitating the polarization of pro-inflammatory macrophages and promoting gut inflammation during weaning.

Neuroprotective Potential of Dendritic Cells and Sirtuins in Multiple Sclerosis

Myeloid cells, including parenchymal microglia, perivascular and meningeal macrophages, and dendritic cells (DCs), are present in the central nervous system (CNS) and establish an intricate relationship with other cells, playing a crucial role both in health and in neurological diseases. In this context, DCs are critical to orchestrating the immune response linking the innate and adaptive immune systems. Under steady-state conditions, DCs patrol the CNS, sampling their local environment and acting as sentinels. During neuroinflammation, the resulting activation of DCs is a critical step that drives the inflammatory response or the resolution of inflammation with the participation of different cell types of the immune system (macrophages, mast cells, T and B lymphocytes), resident cells of the CNS and soluble factors. Although the importance of DCs is clearly recognized, their exact function in CNS disease is still debated. In this review, we will discuss modern concepts of DC biology in steady-state and during autoimmune neuroinflammation. Here, we will also address some key aspects involving DCs in CNS patrolling, highlighting the neuroprotective nature of DCs and emphasizing their therapeutic potential for the treatment of neurological conditions. Recently, inhibition of the NAD⁺-dependent deac(et)ylase sirtuin 6 was demonstrated to delay the onset of experimental autoimmune encephalomyelitis, by dampening DC trafficking towards inflamed LNs. Thus, a special focus will be dedicated to sirtuins’ role in DCs functions.

What Have Failed, Interrupted, and Withdrawn Antibody Therapies in Multiple Sclerosis Taught Us?

In the past two decades, monoclonal antibodies (mAbs) have revolutionized the treatment of multiple sclerosis (MS). However, a remarkable number of mAbs failed due to negative study results were withdrawn because of unexpected serious adverse events (SAEs) or due to studies being halted for other reasons. While trials with positive outcomes are usually published in prestigious journals, negative trials are merely published as abstracts or not at all. This review summarizes MS mAbs that have either failed in phase II-III trials, have been interrupted for various reasons, or withdrawn from the market since 2015. The main conclusions that can be drawn from these 'negative' experiences are as follows. mAbs that have been proven to be safe in other autoimmune conditions, will not have the same safety profile in MS due to immunopathogenetic differences in these diseases (e.g., daclizumab). Identification of SAEs in clinical trials is difficult highlighting the importance of phase IV studies. Memory B cells are central players in MS immunopathogenesis (e.g., tabalumab). The pathophysiological mechanisms of disease progression are independent of leukocyte 'outside-in' traffic which drives relapses in MS. Therefore, therapies for progressive MS must be able to sufficiently cross the blood-brain barrier. Sufficiently long trial duration and multicomponent outcome measures are important for clinical studies in progressive MS. The success of trials on remyelination-promoting therapies mainly depends on the sufficient high dose of mAb, the optimal readout for 'proof of concept', time of treatment initiation, and appropriate selection of patients. Failed strategies are highly important to better understand assumed immunopathophysiological mechanisms and optimizing future trial designs.

The effect of Ccnb1ip1 insulator on monoclonal antibody expression in Chinese hamster ovary cells

BACKGROUND

The increasing need for therapeutic monoclonal antibodies (mAbs) entails the development of innovative and improved expression strategies. Chromatin insulators have been utilized for the enhancement of the heterologous proteins in mammalian cells.

METHODS AND RESULTS

In the current study the Ccnb1ip1 gene insulator element was utilized to construct a novel vector system for the expression of an anti-CD52 mAb in Chinese hamster ovary (CHO) cells. The insulator containing (pIns-mAb) and control (pmAb) vectors were generated and stable cell pools were established using these constructs. The expression level in the cells created with pIns-mAb vector was calculated to be 233 ng/mL, and the expression rate in the control vector was 210 ng/mL, which indicated a 10.9% increase in mAb expression in pIns-mAb pool. In addition, analysis of mAb expression in clonal cells established from each pool showed a 10% increase in antibody productivity in the highest mAb producing clone derived from the pIns-mAb pool compared to the clone isolated from pmAb pool.

CONCLUSIONS

More studies are needed to fully elucidate the effects of Ccnb1ip1 gene insulator on recombinant therapeutic protein expression in mammalian cells. The combination of this element with other chromatin-modifying elements might improve its augmentation effect which could pave the way for efficient and cost-effective production of therapeutic drugs.

Multiple sclerosis and immune system biomarkers: Novel comparison in glatiramer acetate and interferon beta-1a-treated patient groups

BACKGROUND

Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system (CNS). T cells and B lymphocytes are involved in the development of this disease.

METHODS

The following biomarkers were determined in peripheral blood in 28 patients treated with glatiramer acetate (GA) and 21 patients treated with interferon beta 1-a (IFN): IL-10, BAFF, Mx1, IgG, IgG1, IgG2, IgG3 and IgG4 (at baseline and after 6 months of treatment). All participants had confirmed MS diagnosis.

OBJECTIVES

The primary objective is to assess a percentual change of biomarkers after 6 months since the first-line treatment initiation with GA or IFN. The secondary objective is to explore correlations between the baseline biomarkers' values (levels).

RESULTS

A positive trend was observed in the increase in IL-10 concentration by 30.33 % (IFN) and by 15.65 % (GA). In the IFN group, we observed a statistically significant increase in the BAFF protein concentration by 29.9% (P < 0.001). We found that Mx1 protein levels did not change with the administration of GA, which can be explained by the different mechanisms of action of GA. The serum levels of IgG immunoglobulins and both IgG1 and IgG4 subclasses in both groups of patients were increased. Thus, our data were in accordance with the generally accepted assumption that both IFN and GA are capable of modulating the B cell system.

CONCLUSIONS

Our results suggest that treatment with IFN and GA has a more pronounced influence on the B cell system of MS.

ECM1 is an essential factor for the determination of M1 macrophage polarization in IBD in response to LPS stimulation

Inflammatory bowel disease (IBD) comprises chronic relapsing disorders of the gastrointestinal tract characterized pathologically by intestinal inflammation and epithelial injury. Here, we uncover a function of extracellular matrix protein 1 (ECM1) in promoting the pathogenesis of human and mouse IBD. ECM1 was highly expressed in macrophages, particularly tissue-infiltrated macrophages under inflammatory conditions, and ECM1 expression was significantly induced during IBD progression. The macrophage-specific knockout of ECM1 resulted in increased arginase 1 (ARG1) expression and impaired polarization into the M1 macrophage phenotype after lipopolysaccharide (LPS) treatment. A mechanistic study showed that ECM1 can regulate M1 macrophage polarization through the granulocyte-macrophage colony-stimulating factor/STAT5 signaling pathway. Pathological changes in mice with dextran sodium sulfate-induced IBD were alleviated by the specific knockout of the ECM1 gene in macrophages. Taken together, our findings show that ECM1 has an important function in promoting M1 macrophage polarization, which is critical for controlling inflammation and tissue repair in the intestine.

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.

The TNF Family of Ligands and Receptors: Communication Modules in the Immune System and Beyond

The tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies (TNFSF/TNFRSF) include 19 ligands and 29 receptors that play important roles in the modulation of cellular functions. The communication pathways mediated by TNFSF/TNFRSF are essential for numerous developmental, homeostatic, and stimulus-responsive processes in vivo. TNFSF/TNFRSF members regulate cellular differentiation, survival, and programmed death, but their most critical functions pertain to the immune system. Both innate and adaptive immune cells are controlled by TNFSF/TNFRSF members in a manner that is crucial for the coordination of various mechanisms driving either co-stimulation or co-inhibition of the immune response. Dysregulation of these same signaling pathways has been implicated in inflammatory and autoimmune diseases, highlighting the importance of their tight regulation. Investigation of the control of TNFSF/TNFRSF activities has led to the development of therapeutics with the potential to reduce chronic inflammation or promote anti-tumor immunity. The study of TNFSF/TNFRSF proteins has exploded over the last 30 yr, but there remains a need to better understand the fundamental mechanisms underlying the molecular pathways they mediate to design more effective anti-inflammatory and anti-cancer therapies.

The activity of myeloid cell-specific VHH immunotoxins is target-, epitope-, subset- and organ dependent

The central role of myeloid cells in driving autoimmune diseases and cancer has raised interest in manipulating their function or depleting them for therapeutic benefits. To achieve this, antibodies are used to antagonize differentiation, survival and polarization signals or to kill target cells, for example in the form of antibody-drug conjugates (ADC). The action of ADC in vivo can be hard to predict based on target expression pattern alone. The biology of the targeted receptor as well as its interplay with the ADC can have drastic effects on cell apoptosis versus survival. Here we investigated the efficacy of CD11b or Ly-6C/Ly-6G-specific variable fragments of camelid heavy chain-only antibodies (VHH) conjugated to Pseudomonas exotoxin A to deplete myeloid cells in vitro and in vivo. Our data highlight striking differences in cell killing in vivo, depending on the cell subset and organs targeted, but not antigen expression level or VHH affinity. We observed striking differences in depletion efficiency of monocytes versus granulocytes in mice. Despite similar binding of Ly-6C/Ly-6G-specific VHH immunotoxin to granulocytes and monocytes, granulocytes were significantly more sensitive than monocytes to immunotoxins treatment. Our results illustrate the need of early, thorough in vivo characterization of ADC candidates.

Melatonin reduces inflammatory response in peripheral T helper lymphocytes from relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a neuroinflammatory disease of the central nervous system in which the immune system plays a central role. In particular, effector populations such as T helper (Th) 1, Th9, Th17, and Th22 cells are involved in disease development, whereas T regulatory cells (Tregs) are associated with the resolution of the disease. Melatonin levels are impaired in patients with MS, and exogenous melatonin ameliorates the disease in MS animal models by modulating the Th1/Th17/Treg responses and also improves quality of life and several symptoms in patients with MS. However, no study has examined melatonin's effect on T cells from relapsing-remitting MS (RR-MS) patients. Therefore, the objectives of the present study were to evaluate the effects of the in vitro administration of melatonin to peripheral blood mononuclear cells (PBMCs) from 64 RR-MS patients and 64 sex- and age-matched healthy subjects on Th1, Th9, Th17, Th22, and Treg responses and to analyze the expression of the melatonin effector/receptor system in these cells. Melatonin decreased Th1 and Th22 responses in patients, whereas it did not affect the Th17 and Treg subsets. Melatonin also promoted skewing toward a more protective cytokine microenvironment, as shown by an increased anti-inflammatory/Th1 ratio. Furthermore, for the first time, we describe the overexpression of the melatonin effector/receptor system in PBMCs from patients with MS; this alteration might be relevant to the disease because acetylserotonin O-methyltransferase expression significantly correlates with disease progression and T effector/regulatory responses in patients. Therefore, our data suggest that melatonin may be an effective treatment for MS.

Neuroinflammation as modifier of genetically caused neurological disorders of the central nervous system: Understanding pathogenesis and chances for treatment

Genetically caused neurological disorders of the central nervous system (CNS) are usually orphan diseases with poor or even fatal clinical outcome and few or no treatments that will improve longevity or at least quality of life. Neuroinflammation is common to many of these disorders, despite the fact that a plethora of distinct mutations and molecular changes underlie the disorders. In this article, data from corresponding animal models are analyzed to define the roles of innate and adaptive inflammation as modifiers and amplifiers of disease. We describe both common and distinct patterns of neuroinflammation in genetically mediated CNS disorders and discuss the contrasting mechanisms that lead to adverse versus neuroprotective effects. Moreover, we identify the juxtaparanode as a neuroanatomical compartment commonly associated with inflammatory cells and ongoing axonopathic changes, in models of diverse diseases. The identification of key immunological effector pathways that amplify neuropathic features should lead to realistic possibilities for translatable therapeutic interventions using existing immunomodulators. Moreover, evidence emerges that neuroinflammation is not only able to modify primary neural damage-related symptoms but also may lead to unexpected clinical outcomes such as neuropsychiatric syndromes.

Memory B Cells are Major Targets for Effective Immunotherapy in Relapsing Multiple Sclerosis

Although multiple sclerosis (MS) is considered to be a CD4, Th17-mediated autoimmune disease, supportive evidence is perhaps circumstantial, often based on animal studies, and is questioned by the perceived failure of CD4-depleting antibodies to control relapsing MS. Therefore, it was interestingly to find that current MS-treatments, believed to act via T cell inhibition, including: beta-interferons, glatiramer acetate, cytostatic agents, dimethyl fumarate, fingolimod, cladribine, daclizumab, rituximab/ocrelizumab physically, or functionally in the case of natalizumab, also depleted CD19+, CD27+ memory B cells. This depletion was substantial and long-term following CD52 and CD20-depletion, and both also induced long-term inhibition of MS with few treatment cycles, indicating induction-therapy activity. Importantly, memory B cells were augmented by B cell activating factor (atacicept) and tumor necrosis factor (infliximab) blockade that are known to worsen MS. This creates a unifying concept centered on memory B cells that is consistent with therapeutic, histopathological and etiological aspects of MS.

Tiam1/Rac1 complex controls Il17a transcription and autoimmunity

RORγt is a master transcription factor of Th17 cells and considered as a promising drug target for the treatment of autoimmune diseases. Here, we show the guanine nucleotide exchange factor, Tiam1, and its cognate Rho-family G protein, Rac1, regulate interleukin (IL)17A transcription and autoimmunity. Whereas Tiam1 genetic deficiency weakens IL-17A expression partially and inhibits the development of experimental autoimmune encephalomyelitis (EAE), deletion of Rac1 in T cells exhibits more robust effects on Th17 cells and EAE. We demonstrate Tiam1 and Rac1 form a complex with RORγt in the nuclear compartment of Th17 cells, and together bind and activate the Il17 promoter. The clinical relevance of these findings is emphasized by pharmacological targeting of Rac1 that suppresses both murine and human Th17 cells as well as EAE. Thus, our findings highlight a regulatory pathway of Tiam1/Rac1 in Th17 cells and suggest that it may be a therapeutic target in multiple sclerosis.

Tiam1 is a guanine nucleotide exchange factor for the Rho-family GTPase Rac1. Here, the authors show that nuclear Tiam1 and Rac1 bind to RORγt on the IL-17 promoter, activating its transcription, and that inhibiting Tiam1/Rac1 is beneficial in a mouse model of autoimmunity.

Secukinumab (AIN-457) for the treatment of Psoriasis

Secukinumab (also known as AIN-457) is a human monoclonal antibody targeting IL-17A, which has been recently FDA-approved for the treatment of moderate to severe psoriasis and psoriatic arthritis with coexistent moderate to severe plaque psoriasis based on clinical trials demonstrating excellent efficacy. This review will address the rationale for targeting the IL-23/Th17/IL-17 axis, the role of IL-17 and Th17 cells in psoriasis and other chronic inflammatory diseases, and will examine pre-clinical studies, pharmacologic properties, clinical efficacy, and the safety profile of secukinumab.

Depletion of CD4+ CD25+ regulatory T cells confers susceptibility to experimental autoimmune encephalomyelitis (EAE) in GM-CSF-deficient Csf2-/- mice

Previous studies established that GM-CSF-deficient (Csf2-deficient) mice exhibit profound resistance to experimental autoimmune encephalomyelitis. This study addressed whether the resistance of Csf2-deficient mice was a result of a requirement for GM-CSF in controlling the functional balance between effector and regulatory T cell subsets during experimental autoimmune encephalomyelitis. The main observation was that treatment with the anti-CD25 mAb PC61 rendered Csf2-deficient mice fully susceptible to severe, chronic experimental autoimmune encephalomyelitis, with disease incidences and severities equivalent to that of C57BL/6 mice. When both donors and recipients were treated with PC61 in a passive model of experimental autoimmune encephalomyelitis, adoptive transfer of myelin-specific Csf2-deficient T cells into Csf2-deficient recipients resulted in a nonresolving chronic course of severe paralytic experimental autoimmune encephalomyelitis. The peripheral Csf2-deficient T cell repertoire was marked by elevated CD3⁺ T cell frequencies that reflected substantial accumulations of naïve CD44^null-low CD4⁺ and CD8⁺ T cells but essentially normal frequencies of CD4⁺ CD25⁺ forkhead box P3⁺ T cells among the CD3⁺ T cell pool. These findings suggested that Csf2-deficient mice had secondary deficiencies in peripheral T cell sensitization to environmental antigens. In accordance, myelin oligodendrocyte glycoprotein 35-55/CFA-sensitized Csf2-deficient mice exhibited deficient peripheral sensitization to myelin oligodendrocyte glycoprotein, whereas pretreatment of Csf2-deficient mice with PC61 enabled the robust induction of myelin oligodendrocyte glycoprotein-specific T cell responses in the draining lymphatics. In conclusion, the experimental autoimmune encephalomyelitis resistance of Csf2-deficient mice, at least in part, reflects a deficient induction of effector T cell function that cannot surmount normal regulatory T cell barriers. Experimental autoimmune encephalomyelitis effector responses, however, are unleashed upon depletion of regulatory CD25⁺ T cells.

[Infection risks in multiple sclerosis therapy by infusion of disease modifying drugs]

The increased risk of developing infections when using disease-modifying drugs for treatment of multiple sclerosis (MS) is a major challenge in the daily clinical routine. In the growing field of treatment options specific knowledge of treatment-related risks of infections and appropriate preventive and countermeasures is mandatory. Current clinical experience shows that an individual risk stratification is necessary when choosing treatment options and while monitoring during and after treatment administration. The determination of the individual risk of infection in the context of serial use of disease-modifying drugs remains a challenging issue. In addition to the mechanisms of action, the warning notices and current recommendations on infection prophylaxis when using intravenous disease-modifying drugs, such as alemtuzumab, natalizumab and mitoxantron, are presented in detail.

Cell-Surface and Secreted Isoforms of CSF-1 Exert Opposing Roles in Macrophage-Mediated Neural Damage in Cx32-Deficient Mice

Previous studies in myelin-mutant mouse models of the inherited and incurable nerve disorder, Charcot-Marie-Tooth (CMT) neuropathy, have demonstrated that low-grade secondary inflammation implicating phagocytosing macrophages amplifies demyelination, Schwann cell dedifferentiation and perturbation of axons. The cytokine colony stimulating factor-1 (CSF-1) acts as an important regulator of these macrophage-related disease mechanisms, as genetic and pharmacologic approaches to block the CSF-1/CSF-1R signaling result in a significant alleviation of pathological alterations in mutant peripheral nerves. In mouse models of CMT1A and CMT1X, as well as in human biopsies, CSF-1 is predominantly expressed by endoneurial fibroblasts, which are closely associated with macrophages, suggesting local stimulatory mechanisms. Here we investigated the impact of cell-surface and secreted isoforms of CSF-1 on macrophage-related disease in connexin32-deficient (Cx32def) mice, a mouse model of CMT1X. Our present observations suggest that the secreted proteoglycan isoform (spCSF-1) is predominantly expressed by fibroblasts, whereas the membrane-spanning cell-surface isoform (csCSF-1) is expressed by macrophages. Using crossbreeding approaches to selectively restore or overexpress distinct isoforms in CSF-1-deficient (osteopetrotic) Cx32def mice, we demonstrate that both isoforms equally regulate macrophage numbers dose-dependently. However, spCSF-1 mediates macrophage activation and macrophage-related neural damage, whereas csCSF-1 inhibits macrophage activation and attenuates neuropathy. These results further corroborate the important role of secondary inflammation in mouse models of CMT1 and might identify specific targets for therapeutic approaches to modulate innate immune reactions.

SIGNIFICANCE STATEMENT

Mouse models of Charcot-Marie-Tooth neuropathy have indicated that low-grade secondary inflammation involving phagocytosing macrophages amplifies demyelination, Schwann cell dedifferentiation, and perturbation of axons. The recruitment and pathogenic activation of detrimental macrophages is regulated by CSF-1, a cytokine that is mostly expressed by fibroblasts in the diseased nerve and exists in three isoforms. We show that the cell-surface and secreted isoforms of CSF-1 have opposing effects on macrophage activation and disease progression in a mouse model of CMT1X. These insights into opposing functions of disease-modulating cytokine isoforms might enable the development of specific therapeutic approaches.

Th17 Cells Pathways in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders: Pathophysiological and Therapeutic Implications

Several animal and human studies have implicated CD4+ T helper 17 (Th17) cells and their downstream pathways in the pathogenesis of central nervous system (CNS) autoimmunity in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), challenging the traditional Th1-Th2 paradigm. Th17 cells can efficiently cross the blood-brain barrier using alternate ways from Th1 cells, promote its disruption, and induce the activation of other inflammatory cells in the CNS. A number of environmental factors modulate the activity of Th17 pathways, so changes in the diet, exposure to infections, and other environmental factors can potentially change the risk of development of autoimmunity. Currently, new drugs targeting specific points of the Th17 pathways are already being tested in clinical trials and provide basis for the development of biomarkers to monitor disease activity. Herein, we review the key findings supporting the relevance of the Th17 pathways in the pathogenesis of MS and NMOSD, as well as their potential role as therapeutic targets in the treatment of immune-mediated CNS disorders.

Recent Advances in the Treatment of Immune-Mediated Inflammatory Diseases

The treatment of immune-mediated inflammatory diseases (IMIDs) has dramatically improved over the last two decades by the development of a series of targeted biological therapies. This paper focuses on new developments in the treatment of IMIDs. In particular, we discuss how different ways of targeting the same mediators can lead to different efficacy and safety profiles, using B cell targeting as example. In addition, we discuss the emerging field of 'small molecules' that target specifically intracellular processes related to cytokine signaling, cell activation, cell migration, and other processes relevant to tissue inflammation.

Changes in Blood B Cell-Activating Factor (BAFF) Levels in Multiple Sclerosis: A Sign of Treatment Outcome

Multiple sclerosis (MS) is mediated primarily by autoreactive T cells. However, evidence suggesting the involvement of humoral immunity in brain diseases has increased interest in the role of B cells and their products during MS pathogenesis. The major survival factor for B cells, BAFF has been shown to play a role in several autoimmune conditions. Elevated BAFF levels have been reported in MS animal model and during MS relapse in patients. Moreover, disease-modifying treatments (DMT) reportedly influence blood BAFF levels in MS patients, but the significance of these changes remains unclear. The present study addresses how blood BAFF levels are associated with the clinical course of relapsing-remitting MS and the effectiveness of DMT and short-term steroid treatment. During a prospective longitudinal follow-up of 2.3 years, BAFF was measured in the blood of 170 MS patients in the stable phase and within 186 relapses. BAFF levels were significantly higher in MS patients compared to healthy controls. However, stable MS patients without relapses exhibited significantly higher BAFF levels than relapsing patients. Treatment with interferon-β and immunosuppressants raised BAFF blood levels. Interestingly, a similar effect was not seen in patients treated with glatiramer acetate. Short-term treatment with high doses of intravenous methylprednisolone did not significantly alter plasma BAFF levels in 65% of relapsing-remitting MS patients. BAFF were correlated weakly but significantly with monocyte and basophil counts, but not with other blood cell types (neutrophils, lymphocytes, or eosinophils) or inflammatory biomarkers. To our knowledge, this is the first report demonstrating that higher blood BAFF levels may reflect a more stable and effective MS treatment outcome. These results challenge hypotheses suggesting that elevated blood BAFF levels are associated with more severe disease presentation and could explain the recent failure of pharmaceutical trials targeting BAFF with soluble receptor for MS treatment.

Melatonin controls experimental autoimmune encephalomyelitis by altering the T effector/regulatory balance

Experimental autoimmune encephalomyelitis (EAE), the experimental model for multiple sclerosis (MS), is triggered by myelin-specific Th1 and Th17 cells. The immunomodulatory activities of melatonin have been shown to be beneficial under several conditions in which the immune system is exacerbated. Here, we sought to elucidate the basis of the melatonin protective effect on EAE by characterizing the T effector/regulatory responses, particularly those of the memory cell subsets. Melatonin was tested for its effect on Th1, Th17 and T regulatory (Treg) cells in the lymph nodes and CNS of immunodominant peptide of myelin oligodendrocyte glycoprotein (pMOG)-immunized and EAE mice, respectively. The capacity of melatonin to ameliorate EAE as well as modifying both T cell response and effector/regulatory balance was surveyed. T cell memory subsets and CD44, a key activation marker involved in the EAE pathogenesis, were also examined. Melatonin protected from EAE by decreasing peripheral and central Th1/Th17 responses and enhancing both the Treg frequency and IL-10 synthesis in the CNS. Melatonin reduced the T effector memory population and its pro-inflammatory response and regulated CD44 expression, which was decreased in T effector cells and increased in Tregs. The alterations in the T cell subpopulations were associated with a reduced mononuclear infiltration (CD4 and CD11b cells) of the melatonin-treated mice CNS. For the first time, we report that melatonin protects against EAE by controlling peripheral and central T effector/regulatory responses, effects that might be partially mediated by CD44. This immunomodulatory effect on EAE suggests that melatonin may represent an effective treatment option for MS.

Higher expression of IL-12Rβ2 is associated with lower risk of relapse in relapsing-remitting multiple sclerosis patients on interferon-β1b therapy during 3-year follow-up

Cytokines produced by helper T (Th)1 cells, Th17 and regulatory T cells (Treg) are involved in multiple sclerosis (MS) immunopathogenesis. Interferon (IFN)-β alters the numerous genes' expression, but how this alteration affects the treatment response is still elusive. We assessed relative gene expression of nineteen Th1/Th17/Treg-associated mediators in peripheral blood mononuclear cells and plasma levels of GM-CSF, IL-17A and IL-17F, in relapsing-remitting MS (RRMS) patients before IFN-β1b treatment initiation and at 6, 12, 24 and 36 months of therapy. All mRNA levels changed significantly during the IFN-β1b therapy. Higher IL-12Rβ2 mRNA levels were associated with lower risk of relapse. Despite recent reports regarding role of GM-CSF in MS, our study failed to demonstrate its significance as therapy response biomarker, both on the mRNA and protein level.

A critical appraisal of daclizumab use as emerging therapy in multiple sclerosis

INTRODUCTION

Daclizumab (DAC) is a mAb that binds to CD25, a receptor on the surface of lymphocytes for IL-2, a chemical messenger in the immune system. This prevents activation and proliferation of lymphocytes, which are involved in the immune attack in multiple sclerosis (MS).

AREAS COVERED

In this review, we will focus on newly emerging DAC-high-yield process (HYP) therapy for MS. Based on published original articles and citable meeting abstracts, we will discuss its mode of action as well as data on efficacy and safety.

EXPERT OPINION

DAC has been observed to have multiple (biological) effects, which may contribute to beneficial effects in immune-related disease and particularly in relapsing-remitting MS. The positive results in the clinical studies represent achievement of an important milestone in the development of DAC-HYP as a potential new treatment option for MS patients. The benefit/risk ratios of this new biological agent in MS therapy are still being evaluated. Soon, DAC-HYP might qualify as MS therapy. A safety monitoring program is recommended in the clinical practice.

Role of the immunogenic and tolerogenic subsets of dendritic cells in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disorder in the central nervous system (CNS) characterized by inflammation and demyelination as well as axonal and neuronal degeneration. So far effective therapies to reverse the disease are still lacking; most therapeutic drugs can only ameliorate the symptoms or reduce the frequency of relapse. Dendritic cells (DCs) are professional antigen presenting cells (APCs) that are key players in both mediating immune responses and inducing immune tolerance. Increasing evidence indicates that DCs contribute to the pathogenesis of MS and might provide an avenue for therapeutic intervention. Here, we summarize the immunogenic and tolerogenic roles of DCs in MS and review medicinal drugs that may affect functions of DCs and have been applied in clinic for MS treatment. We also describe potential therapeutic molecules that can target DCs by inducing anti-inflammatory cytokines and inhibiting proinflammatory cytokines in MS.

The selective anti-IL17A monoclonal antibody secukinumab (AIN457) attenuates IL17A-induced levels of IL6 in human astrocytes

The family of interleukin 17 receptors (IL17Rs), subtypes IL17RA-IL17RE, is targeted by the group of pro-inflammatory IL17 cytokines (IL17A-F) and moreover the newly developed anti-IL17A antibody secukinumab (AIN457) has shown promise in Phase II trials in multiple sclerosis. Here, we show that human astrocytes, isolated from a fetal cerebral cortex, express IL17RA and IL17RC and in vitro treatment with IL17A increases protein levels of IL6 in human astrocytes, which is enhanced in the presence of TNFα, as determined by homogeneous time resolved fluorescence. Studies on acutely isolated mouse astrocytes are comparable to human astrocytes although the protein levels of IL6 are lower in mouse astrocytes, which also show a lower response to IL17F and IL1β in promoting IL6 levels. In human astrocytes, IL17A and TNFα also induce mRNA expression of IL6, IL8 and the Th17 cytokines CXCL1, CXCL2, and CCL20, with little effect on Th1 cytokines CXCL9, CXCL10, and CXCL11. The effects of IL17A are associated with nuclear translocation of the NF-κB transcription factor, as determined by immunocytochemistry, where treatment of human astrocytes with the inhibitors of the NF-κB pathway and with secukinumab inhibits the IL17A and IL17A/TNFα-induced increase in nuclear translocation of NF-κB and levels of IL6. Taken together the data shows that IL17A signaling plays a key role in regulating the levels of cytokines, such as IL6, in human astrocytes via a mechanism that involves NF-κB signaling and that selective inhibition of IL17A signaling attenuates levels of pro-inflammatory molecules in astrocytes.

MS4A Cluster in Alzheimer's Disease

Several variants within membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated the association of Alzheimer's disease (AD) by serial recent genome-wide association studies (GWAS). As cell membrane proteins, MS4A family members are found to participate in the regulation of calcium signaling which have been widely discussed in neurodegeneration and AD. Besides, although the MS4A family members are poorly characterized, an important role in immunity has already been identified for several members of this cluster (such as MS4A1, MS4A2, and MS4A4B), indicating the possible involvement of MS4A gene cluster in AD pathogenesis. In this article, we briefly summarize the structure, localization, and function of MS4A gene cluster, review recent genetic and expression findings concerning the association of MS4A gene cluster with AD pathogenesis, and also speculate the possible roles of MS4A gene cluster in this disease. Based on the contributing effects of MS4A gene cluster in AD pathogenesis, targeting MS4A gene cluster might provide new opportunities for AD treatment.

Multiple sclerosis treatment and infectious issues: update 2013

Immunomodulation and immunosuppression are generally linked to an increased risk of infection. In the growing field of new and potent drugs for multiple sclerosis (MS), we review the current data concerning infections and prevention of infectious diseases. This is of importance for recently licensed and future MS treatment options, but also for long-term established therapies for MS. Some of the disease-modifying therapies (DMT) go along with threats of specific severe infections or complications, which require a more intensive long-term monitoring and multi-disciplinary surveillance. We update the existing warning notices and infectious issues which have to be considered using drugs for multiple sclerosis.

Role of BAFF/BAFF-R axis in B-cell non-Hodgkin lymphoma

B-cell activating factor (BAFF), as a member of the tumor necrosis factor (TNF) ligand family, plays important roles in B-cell homeostasis, tolerance, and malignancy. BAFF binds to three receptors of TNF, TACI, BCMA and BAFF-receptor (BAFF-R). In particular, the BAFF/BAFF-R pathway is crucial to the survival and growth of mature normal and malignant B-cells. BAFF is displayed on the cell surface or is released in a soluble form after cleavage from the plasma membrane. BAFF-R as the main BAFF receptor is expressed mainly on B-cells. Aberrant BAFF expression was found in malignant B-cells from B-cell non-Hodgkin lymphoma (B-NHL) patients, which protects these cells from spontaneous or drug-induced apoptosis and stimulated NF-κB activation via autocrine and/or paracrine pathways. However, the mechanisms involved in the gene expression and regulation of BAFF or BAFF-R has not been elucidated. More importantly, the design of reagents able to counteract BAFF/BAFF-R pathways may be of therapeutic value for B-NHL. Results of ongoing clinical trials with BAFF or BAFF-R antagonists are eagerly awaited.

Alemtuzumab in the treatment of multiple sclerosis

Alemtuzumab (formerly known as Campath-1H) has recently been approved by the European Medicines Agency for highly-active, relapsing-remitting multiple sclerosis (MS). The molecule targets the CD52 surface glycoprotein on certain T cells and B cells and is thought to exert its effect in MS through a “resetting” of the lymphocyte population. Approval was granted on the strength of two pivotal studies, Comparison of Alemtuzumab and Rebif® Efficacy in Multiple Sclerosis (CARE-MS)-1 in the first-line setting and CARE-MS-2 in patients who had failed first-line therapy. In both studies, alemtuzumab significantly reduced the relapse rate compared to the comparator, interferon beta-1a (44 μg) given subcutaneously three-times per week (Rebif®). In the first-line study, alemtuzumab was also found to significantly reduce the number of patients with sustained progression compared to interferon beta-1a therapy. Autoimmune disorders represent the major side effect of alemtuzumab therapy although they can be managed by careful monitoring and early treatment. Overall, alemtuzumab is likely to be a valuable addition to the neurologist’s armamentarium for the treatment of relapsing-remitting MS.

Novel therapeutic options for multiple sclerosis

Multiple sclerosis (MS) is considered as an autoimmune disorder of the CNS with neuro-inflammatory and neurodegenerative components. We review here the innovative drugs recently registered and those in clinical development for MS. Immunomodulation has been the preferred therapeutic approach for MS since the first IFN-β was registered in the 1990s. Several immunomodulators are now available, which show a high efficacy in reducing the number of relapses in patients with the relapsing-remitting form of MS (RRMS). The high efficacy of most immunomodulators is, however, associated with substantial safety risks, notably concerning infections or cancers. Recently oral drugs have been approved for RRMS; however, biologics, and notably, monoclonal antibodies are still well represented in the development pipelines. An unmet medical need remains the treatment of the primary and secondary forms of MS or chronic progressive MS (CPMS). Half a dozen immunomodulators with proven efficacy in RRMS are now undergoing evaluation in Phase III trials in the CPMS indication. Neuroprotective drugs that prevent demyelination and/or improve remyelination would be interesting for CPMS, but these drugs are currently in the early development phase and their efficacy has not been demonstrated yet.

Highly linear pH gradients for analyzing monoclonal antibody charge heterogeneity in the alkaline range

Recombinant antibodies with high isoelectric point are frequent since most of them are constructed from the same framework. Classically, cation exchange chromatography is used as a standard method for the determination of antibody charge heterogeneity. In contrast, in this study highly linear pH gradients were achieved by keeping the buffering capacity over the length of the gradient constant. The buffering compounds were selected to be unretained on the column and their respective concentration was adjusted in the start and end buffer of the pH gradient to achieve constant buffering capacity. This helps conserve linearity and stability of the gradient. The method allows quantification of charge variant distribution and the determination of chromatographic isoelectric point. To demonstrate the effectiveness of this novel method, a ProPac WCX-10 column was used to separate isoforms of trastuzumab biosimilar antibodies. Effects of pH gradient linearity and of varying the analytical amount of sample on the separation are shown.

Disease modification in multiple sclerosis: an update

Although there has been unequivocal progress in the development of treatments for multiple sclerosis over the last 20&emsp14;years, currently licensed treatments have demonstrated convincing effects on disease course only with reference to relapse frequency. This review summarises the progress made, highlights the indications for, and limitations of, current disease-modifying therapies and discusses some interventions currently in development.

Polyclonal immunoglobulin G for autoimmune demyelinating nervous system disorders

Demyelinating diseases with presumed autoimmune pathogenesis are characterised by direct or indirect immune-mediated damage to myelin sheaths, which normally surround nerve fibres to ensure proper electrical nerve conduction. Parenteral administration of polyclonal IgG purified from multi-donor human plasma pools may beneficially modulate these misguided immune reactions via several mechanisms that are outlined in this review. Convincing therapeutic evidence from controlled trials now exists for certain disorders of the peripheral nervous system, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and multifocal motor neuropathy. In addition, there is evidence for potential therapeutic benefits of IgG in patients with chronic inflammatory demyelinating diseases of the central nervous system, including multiple sclerosis and neuromyelitis optica. This review introduces these disorders, briefly summarises the established treatment options, and discusses therapeutic evidence for the use of polyclonal immunoglobulins with a particular emphasis on recent clinical trials and meta-analyses.