Myelin-reactive B cells exacerbate CD4+ T cell-driven CNS autoimmunity in an IL-23-dependent manner

B cells and T cells collaborate in multiple sclerosis (MS) pathogenesis. IgH[MOG] mice possess a B cell repertoire skewed to recognize myelin oligodendrocyte glycoprotein (MOG). Here, we show that upon immunization with the T cell-obligate autoantigen, MOG[35-55], IgH[MOG] mice develop rapid and exacerbated experimental autoimmune encephalomyelitis (EAE) relative to wildtype (WT) counterparts, characterized by aggregation of T and B cells in the IgH[MOG] meninges and by CD4+ T helper 17 (Th17) cells in the CNS. Production of the Th17 maintenance factor IL-23 is observed from IgH[MOG] CNS-infiltrating and meningeal B cells, and in vivo blockade of IL-23p19 attenuates disease severity in IgH[MOG] mice. In the CNS parenchyma and dura mater of IgH[MOG] mice, we observe an increased frequency of CD4+PD-1+CXCR5- T cells that share numerous characteristics with the recently described T peripheral helper (Tph) cell subset. Further, CNS-infiltrating B and Tph cells from IgH[MOG] mice show increased reactive oxygen species (ROS) production. Meningeal inflammation, Tph-like cell accumulation in the CNS and B/Tph cell production of ROS were all reduced upon p19 blockade. Altogether, MOG-specific B cells promote autoimmune inflammation of the CNS parenchyma and meninges in an IL-23-dependent manner.

Twenty Years of Subcutaneous Interferon-Beta-1a for Multiple Sclerosis: Contemporary Perspectives

Multiple sclerosis (MS) is a chronic, progressive, inflammatory disorder of the central nervous system. Relapsing-remitting MS (RRMS), the most common form of the disease, is characterized by transient neurological dysfunction with concurrent accumulation of disability. Over the past three decades, disease-modifying therapies (DMTs) capable of reducing the frequency of relapses and slowing disability worsening have been studied and approved for use in patients with RRMS. The first DMTs were interferon-betas (IFN-βs), which were approved in the 1990s. Among them was IFN-β-1a for subcutaneous (sc) injection (Rebif®), which was approved for the treatment of MS in Europe and Canada in 1998 and in the USA in 2002. Twenty years of clinical data and experience have supported the efficacy and safety of IFN-β-1a sc in the treatment of RRMS, including pivotal trials, real-world data, and extension studies lasting up to 15 years past initial treatment. Today, IFN-β-1a sc remains an important therapeutic option in clinical use, especially around pregnancy planning and lactation, and may also be considered for aging patients, in which MS activity declines and long-term immunosuppression associated with some alternative therapies is a concern. In addition, IFN-β-1a sc is used as a comparator in many clinical studies and provides a framework for research into the mechanisms by which MS begins and progresses.

The role of regulatory B cells in immune regulation and childhood allergic asthma

BACKGROUND

As the most common chronic disease in childhood, asthma displays a major public health problem worldwide with the incidence of those affected rising. As there is currently no cure for allergic asthma, it is mandatory to get a better understanding of the underlying molecular mechanism.

MAIN BODY

By producing IgE antibodies upon allergen contact, B cells play a pivotal role in allergic asthma. Besides that, IL-10-secreting B cell subsets, namely regulatory B cells (Bregs), are reported in mice and humans to play a role in allergic asthma. In humans, several Breg subsets with distinct phenotypic and functional properties are identified among B cells at different maturational and differentiation stages that exert anti-inflammatory functions by expressing several suppressor molecules. Emerging research has focused on the role of Bregs in allergic asthma as well as their role for future diagnostic and preventive strategies.

CONCLUSION

Knowledge about the exact function of human Bregs in allergic asthma is still very limited. This review aims to summarize the current knowledge on Bregs. We discuss different human Breg subsets, several ways of Breg induction as well as the mechanisms through which they exert immunoregulatory functions, and their role in (childhood) allergic asthma.

Epstein-Barr virus and genetic risk variants as determinants of T-bet+ B cell-driven autoimmune diseases

B cells expressing the transcription factor T-bet are found to have a protective role in viral infections, but are also considered major players in the onset of different types of autoimmune diseases. Currently, the exact mechanisms driving such 'atypical' memory B cells to contribute to protective immunity or autoimmunity are unclear. In addition to general autoimmune-related factors including sex and age, the ways T-bet+ B cells instigate autoimmune diseases may be determined by the close interplay between genetic risk variants and Epstein-Barr virus (EBV). The impact of EBV on T-bet+ B cells likely relies on the type of risk variants associated with each autoimmune disease, which may affect their differentiation, migratory routes and effector function. In this hypothesis-driven review, we discuss the lines of evidence pointing to such genetic and/or EBV-mediated influence on T-bet+ B cells in a range of autoimmune diseases, including systemic lupus erythematosus (SLE) and multiple sclerosis (MS). We provide examples of how genetic risk variants can be linked to certain signaling pathways and are differentially affected by EBV to shape T-bet+ B-cells. Finally, we propose options to improve current treatment of B cell-related autoimmune diseases by more selective targeting of pathways that are critical for pathogenic T-bet+ B-cell formation.

Identification of a novel role for matrix metalloproteinase-3 in the modulation of B cell responses in multiple sclerosis

There has been a growing interest in the presence and role of B cell aggregates within the central nervous system of multiple sclerosis patients. However, very little is known about the expression profile of molecules associated with these aggregates and how they might be influencing aggregate development or persistence in the brain. The current study focuses on the effect of matrix metalloproteinase-3, which is associated with B cell aggregates in autopsied multiple sclerosis brain tissue, on B cells. Autopsied brain sections from multiple sclerosis cases and controls were screened for the presence of CD20⁺ B cell aggregates and expression of matrix metalloproteinase-3. Using flow cytometry, enzyme-linked immunosorbent assay and gene array as methods, in vitro studies were conducted using peripheral blood of healthy volunteers to demonstrate the effect of matrix metalloproteinase-3 on B cells. Autopsied brain sections from multiple sclerosis patients containing aggregates of B cells expressed a significantly higher amount of matrix metalloproteinase-3 compared to controls. In vitro experiments demonstrated that matrix metalloproteinase-3 dampened the overall activation status of B cells by downregulating CD69, CD80 and CD86. Furthermore, matrix metalloproteinase-3-treated B cells produced significantly lower amounts of interleukin-6. Gene array data confirmed that matrix metalloproteinase-3 altered the proliferation and survival profiles of B cells. Taken together, out data indicate a role for B cell modulatory properties of matrix metalloproteinase-3.

Treatment of experimental autoimmune encephalomyelitis using AAV gene therapy by blocking T cell costimulatory pathways

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS), characterized by inflammation and demyelination. Presently, repeated relapses of MS necessitate long-term immune-regulatory therapy. Blocking the CD28-B7 and CD40-CD40L costimulatory pathways is an effective and synergistic method for the prevention and amelioration of clinical symptoms of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. In this study, to explore the efficacy and safety of MS gene therapy, we used adeno-associated virus (AAV) as a vector to deliver CTLA4-immunoglobulin (Ig) or CD40-Ig on the EAE induced by myelin oligodendrocyte glycoprotein (MOG). Our results showed that a single administration of AAV8-CTLA4-Ig, either alone or with AAV8-CD40-Ig, protected mice from EAE and reversed disease progression. Decreased CD4⁺ and CD8⁺ T cell infiltration, inhibition of MOG antibody response, and downregulation of neuroinflammation were observed in mice receiving AAV, suggesting that autoimmunity was suppressed in EAE pathology. Moreover, no hematological or hepatic toxicity was observed in AAV-treated mice. Thus, compared with treatment with recombinant CTLA4-Ig (belatacept), AAV gene therapy could effectively control clinical symptoms and suppress autoimmunity in the long term. In summary, our study provides a potential therapeutic method for blocking T cell costimulation for the treatment of MS via gene therapy.

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.

Treatment-Induced BAFF Expression and B Cell Biology in Multiple Sclerosis

Although fingolimod and interferon-β are two mechanistically different multiple sclerosis (MS) treatments, they both induce B cell activating factor (BAFF) and shift the B cell pool towards a regulatory phenotype. However, whether there is a shared mechanism between both treatments in how they influence the B cell compartment remains elusive. In this study, we collected a cross-sectional study population of 112 MS patients (41 untreated, 42 interferon-β, 29 fingolimod) and determined B cell subsets, cell-surface and RNA expression of BAFF-receptor (BAFF-R) and transmembrane activator and cyclophilin ligand interactor (TACI) as well as plasma and/or RNA levels of BAFF, BAFF splice forms and interleukin-10 (IL-10) and -35 (IL-35). We added an in vitro B cell culture with four stimulus conditions (Medium, CpG, BAFF and CpG+BAFF) for untreated and interferon-β treated patients including measurement of intracellular IL-10 levels. Our flow experiments showed that interferon-β and fingolimod induced BAFF protein and mRNA expression (P ≤ 3.15 x 10^-4) without disproportional change in the antagonizing splice form. Protein BAFF correlated with an increase in transitional B cells (P = 5.70 x 10^-6), decrease in switched B cells (P = 3.29 x 10^-4), and reduction in B cell-surface BAFF-R expression (P = 2.70 x 10^-10), both on TACI-positive and -negative cells. TACI and BAFF-R RNA levels remained unaltered. RNA, plasma and in vitro experiments demonstrated that BAFF was not associated with increased IL-10 and IL-35 levels. In conclusion, treatment-induced BAFF correlates with a shift towards transitional B cells which are enriched for cells with an immunoregulatory function. However, BAFF does not directly influence the expression of the immunoregulatory cytokines IL-10 and IL-35. Furthermore, the post-translational mechanism of BAFF-induced BAFF-R cell surface loss was TACI-independent. These observations put the failure of pharmaceutical anti-BAFF strategies in perspective and provide insights for targeted B cell therapies.

Differential Effects of MS Therapeutics on B Cells-Implications for Their Use and Failure in AQP4-Positive NMOSD Patients

B cells are considered major contributors to multiple sclerosis (MS) pathophysiology. While lately approved disease-modifying drugs like ocrelizumab deplete B cells directly, most MS medications were not primarily designed to target B cells. Here, we review the current understanding how approved MS medications affect peripheral B lymphocytes in humans. These highly contrasting effects are of substantial importance when considering these drugs as therapy for neuromyelitis optica spectrum disorders (NMOSD), a frequent differential diagnosis to MS, which is considered being a primarily B cell- and antibody-driven diseases. Data indicates that MS medications, which deplete B cells or induce an anti-inflammatory phenotype of the remaining ones, were effective and safe in aquaporin-4 antibody positive NMOSD. In contrast, drugs such as natalizumab and interferon-β, which lead to activation and accumulation of B cells in the peripheral blood, lack efficacy or even induce catastrophic disease activity in NMOSD. Hence, we conclude that the differential effect of MS drugs on B cells is one potential parameter determining the therapeutic efficacy or failure in antibody-dependent diseases like seropositive NMOSD.

Glatiramer acetate immune modulates B-cell antigen presentation in treatment of MS

OBJECTIVE

We examined the effect of glatiramer acetate (GA) on B-cell maturation, differentiation, and antigen presentation in MS and experimental autoimmune encephalomyelitis (EAE).

METHODS

A cross-sectional study of blood samples from 20 GA-treated and 18 untreated patients with MS was performed by flow cytometry; 6 GA-treated patients with MS were analyzed longitudinally. GA-mediated effects on B-cell antigen-presenting function were investigated in EAE, or, alternatively, B cells were treated with GA in vitro using vehicle as a control.

RESULTS

In MS, GA diminished transitional B-cell and plasmablast frequency, downregulated CD69, CD25, and CD95 expression, and decreased TNF-α production, whereas IL-10 secretion and MHC Class II expression were increased. In EAE, we observed an equivalent dampening of proinflammatory B-cell properties and an enhanced expression of MHC Class II. When used as antigen-presenting cells for activation of naive T cells, GA-treated B cells promoted development of regulatory T cells, whereas proinflammatory T-cell differentiation was diminished.

CONCLUSIONS

GA immune modulates B-cell function in EAE and MS and efficiently interferes with pathogenic B cell-T cell interaction.

Immunometabolism: an overview and therapeutic prospects in autoimmune diseases

Metabolism is a critical immune regulator under physiologic and pathologic conditions. Culminating evidence has disentangled the contribution of distinct metabolic pathways, namely glucolysis, pentose phosphate, fatty acid oxidation, glutaminolysis, Krebs cycle and oxidative phosphorylation, in modulating innate and adaptive immune cells based on their activation/differentiation state. Metabolic aberrations and changes in the intracellular levels of specific metabolites are linked to the inflammatory phenotype of immune cells implicated in autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and diabetes. Notably, targeting metabolism such as the mTOR by rapamycin, hexokinase by 2-deoxy-D-glucose, AMP-activated protein kinase by metformin, may be used to ameliorate autoimmune inflammation. Accordingly, research in immunometabolism is expected to offer novel opportunities for monitoring and treating immune-mediated diseases.

Acquired factor VIII inhibitor in a patient with multiple sclerosis treated with interferon β-1a

Acquired Factor VIII inhibitor is a rare acquired clotting disorder which has been seen in the setting of particular medications, autoimmune disease, and malignancy. Reports of this disorder in patients receiving immunomodulatory therapies for multiple sclerosis are rare. We present a case of a 48 year-old woman with likely development of acquired Factor VIII inhibitor in the setting of interferon beta monotherapy for multiple sclerosis, and discuss the pathogenesis of this disorder which involves shifts in helper T cell populations and increased production of immunoglobulins.

Understanding regulatory B cells in autoimmune diseases: the case of multiple sclerosis

The suppressive function of B cells is mediated mostly through their provision of cytokines with anti-inflammatory properties, in particular interleukin-10. This B cell activity has been convincingly described in mice with autoimmune, infectious, as well as malignant diseases, and evidence is accumulating of its relevance in human. This review provides a personal view of this B cell function using multiple sclerosis and its animal model experimental autoimmune encephalomyelitis as representative examples, in an attempt to bridge observations obtained in mice and human, with the goal of providing a coherent transversal framework to further explore this field, and eventually manipulate this B cell function therapeutically.

The Multiple Roles of B Cells in Multiple Sclerosis and Their Implications in Multiple Sclerosis Therapies

Increasing evidence has suggested that both antibody-dependent and antibody-independent functions of B cells are involved in multiple sclerosis (MS). The contrasting results of distinct B-cell targeting therapies in MS patients underscores the importance of elucidating these multiple B-cell functions. In this review, we discuss the generation of autoreactive B cells, migration of B cells into the central nervous system (CNS), and how different functions of B cells may contribute to MS disease activity and potentially mitigation in both the periphery and CNS compartments. In addition, we propose several future therapeutic strategies that may better target/shape B-cell responses for long-term treatment of MS.

B-Cell Therapies in Multiple Sclerosis

B cells play a vital function in multiple sclerosis (MS) pathogenesis through an array of effector functions. All currently approved MS disease-modifying therapies alter the frequency, phenotype, or homing of B cells in one way or another. The importance of this mechanism of action has been reinforced with the successful development and clinical testing of B-cell-depleting monoclonal antibodies that target the CD20 surface antigen. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, was approved by the Food and Drug Administration (FDA) in March 2017 after pivotal trials showed dramatic reductions in inflammatory disease activity in relapsing MS as well as lessening of disability progression in primary progressive MS. These and other clinical studies place B cells at the center of the inflammatory cascade in MS and provide a launching point for development of therapies that target selective pathogenic B-cell populations.

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.

Analysis of coding and non-coding transcriptome of peripheral B cells reveals an altered interferon response factor (IRF)-1 pathway in multiple sclerosis patients

Several evidences emphasize B-cell pathogenic roles in multiple sclerosis (MS). We performed transcriptome analyses on peripheral B cells from therapy-free patients and age/sex-matched controls. Down-regulation of two transcripts (interferon response factor 1-IRF1, and C-X-C motif chemokine 10-CXCL10), belonging to the same pathway, was validated by RT-PCR in 26 patients and 21 controls. IRF1 and CXCL10 transcripts share potential seeding sequences for hsa-miR-424, that resulted up-regulated in MS patients. We confirmed this interaction and its functional effect by transfection experiments. Consistent findings indicate down-regulation of IRF1/CXCL10 axis, that may plausibly contribute to a pro-survival status of B cells in MS.

Loss of Gαq impairs regulatory B-cell function

Background

Recent studies have shown a crucial role of Gαq in immune regulation, but how Gαq modulates regulatory B-cell (Breg) function is still unclear. We address this here.

Methods

CD19⁺IL-10⁺ Bregs of wild-type (WT) and Gnaq^−/− mice were analyzed by flow cytometry after stimulation by lipopolysaccharide. The WT and Gnaq^−/− Bregs were isolated and cocultured with WT CD4⁺CD25⁻ T cells in the presence of T-activator, and the proliferation of T cells and differentiation of regulatory T cells (Tregs) were analyzed by flow cytometry. We used inhibitors of PI3 kinase (PI3K), extracellular regulated protein kinases 1/2 (Erk1/2), and p38 mitogen-activated protein kinase (p38 MAPK) to detect the pathways involved in the regulation of Gαq on Breg differentiation, which were confirmed by western blot analysis. Furthermore, the expression level of Gαq was assessed by quantitative real-time PCR in peripheral blood mononuclear cells (PBMCs) from healthy controls and rheumatoid arthritis patients. The frequency of CD19⁺CD24^hiCD38^hi B cells in PBMCs was detected by flow cytometry, and the association of the Gαq mRNA expression level and the frequency of CD19⁺CD24^hiCD38^hi B cells was analyzed by Spearman test.

Results

The differentiation of CD19⁺IL-10⁺ Bregs was inhibited in the Gnaq^−/− mice. In addition, Gαq depletion showed an impaired suppressive function of Bregs on T-cell proliferation, which might be due to the decreased Treg expansion. Mechanically, our data demonstrated that the PI3K, Erk1/2, and p38 MAPK signaling pathways were required for regulation of Gαq on Bregs, and blockage of these signaling pathways impaired Breg differentiation. Consistent with our previous studies, we also found a decreased frequency of CD19⁺CD24^hiCD38^hi Bregs in rheumatoid arthritis patients. As expected, a significantly positive correlation was investigated between CD19⁺CD24^hiCD38^hi Bregs with Gαq mRNA expression.

Conclusions

Our results indicate that Gαq plays a critical role in the differentiation and immunosuppression of Bregs, and it may provide a new therapeutic target for autoimmune diseases.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1682-0) contains supplementary material, which is available to authorized users.

Peripheral blood lymphocytes immunophenotyping predicts disease activity in clinically isolated syndrome patients

Background

Clinically isolated syndrome (CIS) represents first neurological symptoms suggestive of demyelinating lesion in the central nervous system (CNS). Currently, there are no sufficient immunological or genetic markers predicting relapse and disability progression, nor there is evidence of the efficacy of registered disease modifying treatments (DMTs), such as intramuscular interferon beta1a. The aim of the study is to evaluate immunological predictors of a relapse or disability progression.

Methods

One hundred and eighty one patients with CIS were treated with interferon beta1a and followed over the period of 4 years. Lymphocyte subsets were analyzed by flow cytometry. A Kaplan-Meier estimator of survival probability was used to analyze prognosis. For statistical assessment only individual differences between baseline values and values at the time of relapse or confirmed disability progression were analysed.

Results

Higher levels of B lymphocytes predicted relapse-free status. On the other hand, a decrease of the naïve subset of cells (CD45RA+ in CD4+) after 12, 24, and 36 months of follow-up were associated with an increased risk of confirmed disability progression. Conclusion: Our data suggest that the quantification of lymphocyte subsets in patients after the first demyelinating event suggestive of MS may be an important biomarker.

Spasticity in multiple sclerosis: Contribution of inflammation, autoimmune mediated neuronal damage and therapeutic interventions

In contrast to other diseases that go along with spasticity (e.g. spinal cord injury), spasticity in chronic autoimmune diseases involving the CNS is complicated by the ongoing damage of neuronal networks that leads to permanent changes in the clinical picture of spasticity. Multiple sclerosis (MS) is the most frequent autoimmune disease of the central nervous system (CNS) and spasticity is one of the most disabling symptoms. It occurs in more than 80% MS patients at some point of the disease and is associated with impaired ambulation, pain and the development of contractures. Besides causing cumulative structural damage, neuroinflammation occurring in MS leads to dynamic changes in motor circuit function and muscle tone that are caused by cytokines, prostaglandins, reactive oxygen species and stress hormones that affect neuronal circuits and thereby spasticity. The situation is complicated further by the fact that therapeutics used for the immunotherapy of MS may worsen spasticity and drugs used for the symptomatic treatment of spasticity have been shown to have the potential to alter immune cell function and CNS autoimmunity itself. This review summarizes the current knowledge on the immunologic pathways that are involved in the development, maintenance, dynamic changes and pharmacological modulation of spasticity 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.

Advances in the treatment of relapsing-remitting multiple sclerosis: the role of pegylated interferon β-1a

Multiple sclerosis (MS) is a progressive, neurodegenerative disease with unpredictable phases of relapse and remission. The cause of MS is unknown, but the pathology is characterized by infiltration of auto-reactive immune cells into the central nervous system (CNS) resulting in widespread neuroinflammation and neurodegeneration. Immunomodulatory-based therapies emerged in the 1990s and have been a cornerstone of disease management ever since. Interferon β (IFNβ) was the first biologic approved after demonstrating decreased relapse rates, disease activity and progression of disability in clinical trials. However, frequent dosing schedules have limited patient acceptance for long-term therapy. Pegylation, the process by which molecules of polyethylene glycol are covalently linked to a compound, has been utilized to increase the half-life of IFNβ and decrease the frequency of administration required. To date, there has been one clinical trial evaluating the efficacy of pegylated IFN. The purpose of this article is to provide an overview of the role of IFN in the treatment of MS and evaluate the available evidence for pegylated IFN therapy in MS.

CD40-Mediated NF-κB Activation in B Cells Is Increased in Multiple Sclerosis and Modulated by Therapeutics

CD40 interacts with CD40L and plays an essential role in immune regulation and homeostasis. Recent research findings, however, support a pathogenic role of CD40 in a number of autoimmune diseases. We previously showed that memory B cells from relapsing-remitting multiple sclerosis (RRMS) patients exhibited enhanced proliferation with CD40 stimulation compared with healthy donors. In this study, we used a multiparameter phosflow approach to analyze the phosphorylation status of NF-κB and three major MAPKs (P38, ERK, and JNK), the essential components of signaling pathways downstream of CD40 engagement in B cells from MS patients. We found that memory and naive B cells from RRMS and secondary progressive MS patients exhibited a significantly elevated level of phosphorylated NF-κB (p-P65) following CD40 stimulation compared with healthy donor controls. Combination therapy with IFN-β-1a (Avonex) and mycophenolate mofetil (Cellcept) modulated the hyperphosphorylation of P65 in B cells of RRMS patients at levels similar to healthy donor controls. Lower disease activity after the combination therapy correlated with the reduced phosphorylation of P65 following CD40 stimulation in treated patients. Additionally, glatiramer acetate treatment also significantly reduced CD40-mediated P65 phosphorylation in RRMS patients, suggesting that reducing CD40-mediated p-P65 induction may be a general mechanism by which some current therapies modulate MS disease.

Intranasal Administration of Interferon Beta Attenuates Neuronal Apoptosis via the JAK1/STAT3/BCL-2 Pathway in a Rat Model of Neonatal Hypoxic-Ischemic Encephalopathy

Neonatal hypoxic-ischemic encephalopathy (HIE) is an injury that often leads to detrimental neurological deficits. Currently, there are no established therapies for HIE and it is critical to develop treatments that provide protection after HIE. The objective of this study was to investigate the ability of interferon beta (IFNβ) to provide neuroprotection and reduce apoptosis after HIE. Postnatal Day 10 rat pups were subjected to unilateral carotid artery ligation followed by 2.5 hr of exposure to hypoxia (8% O2). Intranasal administration of human recombinant IFNβ occurred 2 hr after HIE and infarct volume, body weight, neurobehavioral tests, histology, immunohistochemistry, brain water content, blood-brain barrier permeability, enzyme-linked immunosorbent assay, and Western blot were all used to evaluate various parameters. The results showed that both IFNβ and the Type 1 interferon receptor expression decreases after HIE. Intranasal administration of human recombinant IFNβ was able to be detected in the central nervous system and was able to reduce brain infarction volumes and improve neurological behavior tests 24 hr after HIE. Western blot analysis also revealed that human recombinant IFNβ treatment stimulated Stat3 and Bcl-2 expression leading to a decrease in cleaved caspase-3 expression after HIE. Positive Fluoro-Jade C staining also demonstrated that IFNβ treatment was able to decrease neuronal apoptosis. Furthermore, the beneficial effects of IFNβ treatment were reversed when a Stat3 inhibitor was applied. Also an intraperitoneal administration of human recombinant IFNβ into the systemic compartment was unable to confer the same protective effects as intranasal IFNβ treatment.

Treatment of ongoing autoimmune encephalomyelitis with activated B-cell progenitors maturing into regulatory B cells

The influence of signals perceived by immature B cells during their development in bone marrow on their subsequent functions as mature cells are poorly defined. Here, we show that bone marrow cells transiently stimulated in vivo or in vitro through the Toll-like receptor 9 generate proB cells (CpG-proBs) that interrupt experimental autoimmune encephalomyelitis (EAE) when transferred at the onset of clinical symptoms. Protection requires differentiation of CpG-proBs into mature B cells that home to reactive lymph nodes, where they trap T cells by releasing the CCR7 ligand, CCL19, and to inflamed central nervous system, where they locally limit immunopathogenesis through interleukin-10 production, thereby cooperatively inhibiting ongoing EAE. These data demonstrate that a transient inflammation at the environment, where proB cells develop, is sufficient to confer regulatory functions onto their mature B-cell progeny. In addition, these properties of CpG-proBs open interesting perspectives for cell therapy of autoimmune diseases.

Evidence of how functional Bregs develop in vivo has been lacking. Here the authors show that proB cells exposed in vivo to CpG differentiate into distinct Breg subsets that inhibit autoimmunity by arresting T cells in the lymph nodes via CCL19 and by producing IL-10 at the site of immunopathology.

Further understanding of the immunopathology of multiple sclerosis: impact on future treatments

INTRODUCTION

The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena.

AREAS COVERED

In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.

Paeoniflorin suppresses IL-6/Stat3 pathway via upregulation of Socs3 in dendritic cells in response to 1-chloro-2,4-dinitrobenze

Mounting evidence has suggested that inflammation is associated with IL-6/Stat3 pathway in dendritic cells (DCs) and Th17 cells, which are critical for development of allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proved to be effective in the treatment of inflammatory skin diseases such as ACD. We have previously demonstrated the effect of PF on DCs stimulated with 1-chloro-2,4-dinitrobenze (DNCB) and naïve CD4(+)CD45RA(+) T cells for Th17 cell differentiation. However, whether PF down-regulates IL-6/Stat3 in DCs and Th17 cells remains to be explored. In this study, we show clearly that PF markedly decreases IL-6/Stat3 in DCs stimulated with DNCB at both gene and protein levels compared with control DCs in vitro. Meanwhile, PF up-regulates suppressor of cytokine signaling 3 (Socs3). Such decreased expression of IL-6/Stat3 is abolished in DCs that were transfected with Socs3 short interfering RNA (siRNA). When mice CD4(+)CD45 RA(+) T cells were co-cultured with PF-treated DCs stimulated with/without DNCB, the gene expression of the Th17 cell markers such as retinoic acid-related orphan nuclear hormone receptor γt (RORγt), IL-17A, and IL-23R decreased, in accordance with the less secretions of IL-17 and IL-23 in vitro and in vivo. Finally, the suppressed Th17 differentiation induced by PF can be abolished by additional recombinant mouse IL-6. Our results suggest that the anti-inflammatory mechanisms introduced by depletion of Socs3 expression or inactivation of the negative regulator such as Socs3 may represent a promising strategy for the prevention of ACD.

Cytokine-Defined B Cell Responses as Therapeutic Targets in Multiple Sclerosis

Important antibody-independent pathogenic roles of B cells are emerging in autoimmune diseases, including multiple sclerosis (MS). The contrasting results of different treatments targeting B cells in patients (in spite of predictions of therapeutic benefits from animal models) call for a better understanding of the multiple roles that distinct human B cell responses likely play in MS. In recent years, both murine and human B cells have been identified with distinct functional properties related to their expression of particular cytokines. These have included regulatory (Breg) B cells (secreting interleukin (IL)-10 or IL-35) and pro-inflammatory B cells (secreting tumor necrosis factor α, LTα, IL-6, and granulocyte macrophage colony-stimulating factor). Better understanding of human cytokine-defined B cell responses is necessary in both health and diseases, such as MS. Investigation of their surface phenotype, distinct functions, and the mechanisms of regulation (both cell intrinsic and cell extrinsic) may help develop effective treatments that are more selective and safe. In this review, we focus on mechanisms by which cytokine-defined B cells contribute to the peripheral immune cascades that are thought to underlie MS relapses, and the impact of B cell-directed therapies on these mechanisms.

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.

The brain antigen-specific B cell response correlates with glatiramer acetate responsiveness in relapsing-remitting multiple sclerosis patients

B cells have only recently begun to attract attention in the immunopathology of multiple sclerosis (MS). Suitable markers for the prediction of treatment success with immunomodulatory drugs are still missing. Here we evaluated the B cell response to brain antigens in n = 34 relapsing-remitting MS (RRMS) patients treated with glatiramer acetate (GA) using the enzyme-linked immunospot technique (ELISPOT). Our data demonstrate that patients can be subdivided into responders that show brain-specific B cell reactivity in the blood and patients without this reactivity. Only in patients that classified as B cell responders, there was a significant positive correlation between treatment duration and the time since last relapse in our study. This correlation was GA-specific because it was absent in a control group that consisted of interferon-ß (IFN-β)-treated RRMS patients (n = 23). These data suggest that GA has an effect on brain-reactive B cells in a subset of patients and that only this subset benefits from treatment. The detection of brain-reactive B cells is likely to be a suitable tool to identify drug responders.

Seeking balance: Potentiation and inhibition of multiple sclerosis autoimmune responses by IL-6 and IL-10

The cytokines IL-6 and IL-10 are produced by cells of the adaptive and innate arms of the immune system and they appear to play key roles in genetically diverse autoimmune diseases such as relapsing remitting multiple sclerosis (MS), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Whereas previous intense investigations focused on the generation of autoantibodies and their contribution to immune-mediated pathogenesis in these diseases; more recent attention has focused on the roles of cytokines such as IL-6 and IL-10. In response to pathogens, antigen presenting cells (APC), including B cells, produce IL-6 and IL-10 in order to up-or down-regulate immune cell activation and effector responses. Evidence of elevated levels of the proinflammatory cytokine IL-6 has been routinely observed during inflammatory responses and in a number of autoimmune diseases. Our recent studies suggest that MS peripheral blood B cells secrete higher quantities of IL-6 and less IL-10 than B cells from healthy controls. Persistent production of IL-6, in turn, contributes to T cell expansion and the functional hyperactivity of APC such as MS B cells. Altered B cell activity can have a profound impact on resultant T cell effector functions. Enhanced signaling through the IL-6 receptor can effectively inhibit cytolytic activity, induce T cell resistance to IL-10-mediated immunosuppression and increase skewing of autoreactive T cells to a pathogenic Th17 phenotype. Our recent findings and studies by others support a role for the indirect attenuation of B cell responses by Glatiramer acetate (GA) therapy. Our studies suggest that GA therapy temporarily permits homeostatic regulatory mechanisms to be reinstated. Future studies of mechanisms underlying dysregulated B cell cytokine production could lead to the identification of novel targets for improved immunoregulatory therapies for autoimmune diseases.

Gut commensalism, cytokines, and central nervous system demyelination

There is increasing support for the importance of risk factors such as genetic makeup, obesity, smoking, vitamin D insufficiency, and antibiotic exposure contributing to the development of autoimmune diseases, including human multiple sclerosis (MS). Perhaps the greatest environmental risk factor associated with the development of immune-mediated conditions is the gut microbiome. Microbial and helminthic agents are active participants in shaping the immune systems of their hosts. This concept is continually reinforced by studies in the burgeoning area of commensal-mediated immunomodulation. The clinical importance of these findings for MS is suggested by both their participation in disease and, perhaps of greater clinical importance, attenuation of disease severity. Observations made in murine models of central nervous system demyelinating disease and a limited number of small studies in human MS suggest that immune homeostasis within the gut microbiome may be of paramount importance in maintaining a disease-free state. This review describes three immunological factors associated with the gut microbiome that are central to cytokine network activities in MS pathogenesis: T helper cell polarization, T regulatory cell function, and B cell activity. Comparisons are drawn between the regulatory mechanisms attributed to first-line therapies and those described in commensal-mediated amelioration of central nervous system demyelination.

Cell-specific effects in different immune subsets associated with SOCS1 genotypes in multiple sclerosis

BACKGROUND

Single nucleotide polymorphisms (SNPs) near SOCS1 are associated with multiple sclerosis (MS), but the most important SNPs in the area and mechanisms by which they influence the disease are unknown.

METHODS

A haplotype-tagging association study was performed covering 60.5kbp around SOCS1, and the index SNP was validated in a total of 2292 individuals. mRNA expression of SOCS1 and nearby genes was measured in MS patients with different disease courses and healthy controls. SOCS1 protein expression was studied by flow cytometry in a separate cohort of patients and controls. Differentiation and maturation of monocyte-derived dendritic cells (moDCs) were also studied.

RESULTS

One SNP, rs423674, reached genome-wide significance. No genotype-specific mRNA expression differences were seen, but, by flow cytometry, significant interactions were observed between genotypes for rs423674 and disease activity (relapse or remission) in B cells and regulatory T cells. Furthermore, homozygotes for the risk allele (GG) showed higher levels of CD1a and CD86 than carriers of the protective allele (GT) in immature moDCs and a greater increase of HLA-DR+ cell percentage than GT heterozygotes upon maturation.

CONCLUSIONS

rs423674, or its genetic proxies, may influence MS risk by modulating SOCS1 expression in a cell-specific manner and by influencing dendritic cell function.

Immunosuppressive effect of Chinese medicine on T helper 17 cells

T helper (Th)17 cells have been proposed to play important roles in several human diseases. The literatures about Chinese medicine studies, which related to inhibiting Th17, were reviewed, and the Chinese medicine which could inhibit Th17 cells was summarized in this paper.

Retinoic acid enhances the levels of IL-10 in TLR-stimulated B cells from patients with relapsing-remitting multiple sclerosis

We have explored the beneficial effects of retinoic acid (RA) on B cells from multiple sclerosis (MS) patients. When co-stimulated via the toll-like receptors (TLRs) TLR9 and RP105, MS B cells secreted less of the anti-inflammatory cytokine interleukin 10 (IL-10) compared to B cells from healthy controls. Importantly, RA enhanced the secretion of IL-10 by MS-derived B cells without affecting the levels of the pro-inflammatory cytokine TNF-α. RA revealed the same ability to induce IL-10 as did interferon-β-1b (IFN-β-1b), and B-cells from patients treated with glatiramer acetate or IFN-β-1b still displayed the beneficial effects of RA on the IL-10/TNF-α ratio.

IFN-β and multiple sclerosis: cross-talking of immune cells and integration of immunoregulatory networks

Multiple sclerosis (MS) is characterized by autoimmune inflammation affecting the central nervous system and subsequent neurodegeneration. Historically, damage was thought to be mediated exclusively by auto-antigen-activated pro-inflammatory T cells. However, more recently, we are gaining increasing knowledge on the pathogenic role played in MS by B cells, dendritic cells and monocytes. IFN-β therapy was one the first approved therapy for MS for its ability to reduce relapse rate and MRI lesion activity and to significantly decrease risk of disability progression. IFN-β-mediated mechanisms of action, even if not completely understood, mainly rely on its multifaceted pleiotropic effects resulting in sustained anti-inflammatory properties directed toward almost every immune cell type. Here, we will discuss in detail literature data characterizing the pathogenic activity of the different immune cell subsets involved in MS pathogenesis and how IFN-β therapy regulates their function by modulating bystander responses. We believe that the effectiveness of this drug in MS treatment, even if in use for a long time, can unveil new insights on this disease and still teach a lesson to researchers in the MS field.

Gene expression profiling of the response to interferon beta in Epstein-Barr-transformed and primary B cells of patients with multiple sclerosis

The effects of interferon-beta (IFN-β), one of the key immunotherapies used in multiple sclerosis (MS), on peripheral blood leukocytes and T cells have been extensively studied. B cells are a less abundant leukocyte type, and accordingly less is known about the B cell-specific response to IFN-β. To identify gene expression changes and pathways induced by IFN-β in B cells, we studied the in vitro response of human Epstein Barr-transformed B cells (lymphoblast cell lines-LCLs), and validated our results in primary B cells. LCLs were derived from an MS patient repository. Whole genome expression analysis identified 115 genes that were more than two-fold differentially up-regulated following IFN-β exposure, with over 50 previously unrecognized as IFN-β response genes. Pathways analysis demonstrated that IFN-β affected LCLs in a similar manner to other cell types by activating known IFN-β canonical pathways. Additionally, IFN-β increased the expression of innate immune response genes, while down-regulating many B cell receptor pathway genes and genes involved in adaptive immune responses. Novel response genes identified herein, NEXN, DDX60L, IGFBP4, and HAPLN3, B cell receptor pathway genes, CD79B and SYK, and lymphocyte activation genes, LAG3 and IL27RA, were validated as IFN-β response genes in primary B cells. In this study new IFN-β response genes were identified in B cells, with possible implications to B cell-specific functions. The study's results emphasize the applicability of LCLs for studies of human B cell drug response. The usage of LCLs from patient-based repositories may facilitate future studies of drug response in MS and other immune-mediated disorders with a B cell component.

The role of endogenous IFN-β in the regulation of Th17 responses in patients with relapsing-remitting multiple sclerosis

IFN-β has been used as a first-line therapy for relapsing-remitting multiple sclerosis (RRMS). Because only a few studies have addressed the role of endogenous IFN-β in the pathogenesis of the disease, our objective was to characterize its role in the transcriptional regulation of pathogenic Th17 cytokines in patients with RRMS. In vitro studies have demonstrated that IFN-β inhibits IL-17A, IL-17F, IL-21, IL-22, and IFN-γ secretion in CD4(+) lymphocytes through the induction of suppressor of cytokine secretion 1 and suppressor of cytokine secretion 3. We found that patients with RRMS have increased serum and cerebrospinal fluid Th17 (IL-17A and IL-17F) cytokine levels in comparison with the control subjects, suggesting that deficient endogenous IFN-β secretion or signaling can contribute to the dysregulation of those pathogenic cytokines in CD4(+) cells. We identified that the endogenous IFN-β from serum of RRMS patients induced a significantly lower IFN-inducible gene expression in comparison with healthy controls. In addition, in vitro studies have revealed deficient endogenous and exogenous IFN-β signaling in the CD4(+) cells derived from patients with MS. Interestingly, upon inhibition of the endogenous IFN-β signaling by silencing IFN regulatory factor (IRF) 7 gene expression, the resting CD4(+) T cells secreted significantly higher level of IL-17A, IL-17F, IL-21, IL-22, and IL-9, suggesting that endogenous IFN-β suppresses the secretion of these pathogenic cytokines. In vivo recombinant IFN-β-1a treatment induced IFNAR1 and its downstream signaling molecules' gene expression, suggesting that treatment reconstitutes a deficient endogenous IFN-β regulation of the CD4(+) T cells' pathogenic cytokine production in patients with MS.

Regulatory lymphocytes are key factors in MHC-independent resistance to EAE

BACKGROUND AND OBJECTIVES

Resistant and susceptible mouse strains to experimental autoimmune encephalomyelitis (EAE), an inducible demyelinating experimental disease serving as animal model for multiple sclerosis, have been described. We aimed to explore MHC-independent mechanisms inducing resistance to EAE.

METHODS

For EAE induction, female C57BL/6 (susceptible strain) and CD1 (resistant outbred strain showing heterogeneous MHC antigens) mice were immunized with the 35-55 peptide of myelin oligodendrocyte glycoprotein (MOG35-55). We studied T cell proliferation, regulatory and effector cell subpopulations, intracellular and serum cytokine patterns, and titers of anti-MOG serum antibodies.

RESULTS

Upon immunization with MOG35-55, T lymphocytes from susceptible mice but not that of resistant strain were capable of proliferating when stimulated with MOG35-55. Accordingly, resistant mice experienced a rise in regulatory B cells (P=0.001) and, to a lower extent, in regulatory T cells (P=0.02) compared with C57BL/6 susceptible mice. As a consequence, MOG35-55-immunized C57BL/6 mice showed higher percentages of CD4+ T cells producing both IFN-gamma (P=0.02) and IL-17 (P=0.009) and higher serum levels of IL-17 (P=0.04) than resistant mice.

CONCLUSIONS

Expansion of regulatory B and T cells contributes to the induction of resistance to EAE by an MHC-independent mechanism.

B1 cells are unaffected by immune modulatory treatment in remitting-relapsing multiple sclerosis patients

In this study we aimed to investigate whether treatment with an immune modulatory drug had an effect on the distribution of B cell subpopulations in patients with remitting-relapsing multiple sclerosis (RRMS). We investigated the first-line drugs glatiramer acetate, interferon-β and natalizumab. Our data show that the frequency of the CD27(+)CD43(+) B1 cell subset was significantly diminished in RRMS patients compared to healthy subjects and that this subset was unaffected by treatment. Regardless of their true nature, we believe that these cells are part of the autoimmune disease pattern.

CD80+ and CD86+ B cells as biomarkers and possible therapeutic targets in HTLV-1 associated myelopathy/tropical spastic paraparesis and multiple sclerosis

Background

Human T-cell lymphotropic virus (HTLV-1) is the causative agent of the incapacitating, neuroinflammatory disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Currently, there are no disease-modifying therapies with long-term clinical benefits or validated biomarkers for clinical follow-up in HAM/TSP. Although CD80 and CD86 costimulatory molecules play prominent roles in immune regulation and reflect disease status in multiple sclerosis (MS), data in HAM/TSP are lacking.

Methods

Using flow cytometry, we quantified ex vivo and in vitro expression of CD80 and CD86 in PBMCs of healthy controls, HTLV-1-infected individuals with and without HAM/TSP, and MS patients. We hypothesized ex vivo CD80 and CD86 expressions and their in vitro regulation by interferon (IFN)-α/β mirror similarities between HAM/TSP and MS and hence might reveal clinically useful biomarkers in HAM/TSP.

Results

Ex vivo expression of CD80 and CD86 in T and B cells increased in all HTLV-1 infected individuals, but with a selective defect for B cell CD86 upregulation in HAM/TSP. Despite decreased total B cells with increasing disease duration (p = 0.0003, r = −0.72), CD80⁺ B cells positively correlated with disease severity (p = 0.0017, r = 0.69) in HAM/TSP. B cell CD80 expression was higher in women with HAM/TSP, underscoring that immune markers can reflect the female predominance observed in most autoimmune diseases. In contrast to MS patients, CD80⁺ (p = 0.0001) and CD86⁺ (p = 0.0054) lymphocytes expanded upon in vitro culture in HAM/TSP patients. The expansion of CD80⁺ and CD86⁺ T cells but not B cells was associated with increased proliferation in HTLV-1 infection. In vitro treatment with IFN-β but not IFN-α resulted in a pronounced increase of B cell CD86 expression in healthy controls, as well as in patients with neuroinflammatory disease (HAM/TSP and MS), similar to in vivo treatment in MS.

Conclusions

We propose two novel biomarkers, ex vivo CD80⁺ B cells positively correlating to disease severity and CD86⁺ B cells preferentially induced by IFN-β, which restores defective upregulation in HAM/TSP. This study suggests a role for B cells in HAM/TSP pathogenesis and opens avenues to B cell targeting (with proven clinical benefit in MS) in HAM/TSP but also CD80-directed immunotherapy, unprecedented in both HAM/TSP and MS.

Interleukin-10-producing B cells and the regulation of immunity

B cells are usually considered primarily for their unique capacity to produce antibodies after differentiation into plasma cells. In addition to their roles as antibody-producing cells, it has become apparent during the last 10 years that B cells also perform important functions in immunity through the production of cytokines. In particular, it was shown that B cells could negatively regulate immunity through provision of interleukin (IL)-10 during autoimmune and infectious diseases in mice. Here, we review data on the suppressive functions of B cells in mice with particular emphasis on the signals controlling the acquisition of such suppressive functions by B cells, the phenotype of the B cells involved in the negative regulation of immunity, and the processes targeted by this inhibitory circuit. Finally, we discuss the possibility that human B cells might also perform similar inhibitory functions through the provision of IL-10, and review data suggesting that such B cell-mediated regulatory activities might be impaired in patients with autoimmune diseases.

B-cell targeting agents in the treatment of multiple sclerosis

OPINION STATEMENT

The aims of this article are to discuss the potential role of B lymphocytes in the pathogenesis of multiple sclerosis (MS) and in the mechanisms of action of approved and emerging disease modifying therapies. Over the last few years, significant progress has been made in the introduction of novel pharmacologic treatments that reduce the frequency of clinical exacerbations and radiological lesion formation in relapsing remitting MS. The mechanisms of action of a number of these disease modifying therapies (DMT) implicate B cells in the pathogenesis, as well as in the regulation, of MS. Further research into B-cell subset trafficking patterns, functional activities and interactions with other immune cells in the context of neuroinflammation is likely to inform the development of future generations of DMT.