B cell-based therapies in CNS autoimmunity: differentiating CD19 and CD20 as therapeutic targets

Review of approved NMO therapies based on mechanism of action, efficacy and long-term effects

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Neuromyelitis optica (NMO - including NMO spectrum disorders [NMOSD]) is a devastating disease.

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Up until recently, there was no proven agent to treat to prevent relapses.

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We now have three agents indicated for the treatment of NMO.

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We might suggest the following sequence – 1st line using eculizumab for rapid efficacy and stabilization without effect on the acquired immune system followed by satrilizumab (long term immunomodulation).

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Reserve inebilizumab (immunosuppressant) for breakthrough disease and salvage the severe with AHSCBMT.

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In NMO, control the complement, transition to modulation, and reserve suppression – and salvage the severe with AHSCBMT.

Importance

Neuromyelitis optica (NMO - including NMO spectrum disorders [NMOSD]) is a devastating disease. Eighty-three percent of patients with transverse myelitic (TM) attacks and 67% of patients with optic neuritis (ON) attacks have no or a partial recovery.

Observations

Up until recently, there was no proven agent to treat to prevent relapses. The neuro-immunological community had a dearth of indicated agents for NMOSD. We now have three agents indicated for the treatment of NMO including (eculizumab [Soliris®]), an anti-C5 complement inhibitor, satralizumab (ENSRYNG®), a monoclonal antibody against the IL-6 receptor (IL-6R) that blocks B cell antibody production and inebilizumab (Uplinza®), a monoclonal antibody that binds to the B-cell surface antigen CD19 with subsequent B and plasmablast cell lymphocytolysis with decreasing antibody production. Autologous hematopoietic stem cell bone marrow transplantation (AHSCBMT) has also been used. How do we sequence NMO therapies with the understanding of the acuteness and severity of the disease, the individual mechanism of action (MOA) and rapidity of onset of action, onset of efficacy and long-term safety of each agent?

Conclusions and Relevance

We might suggest the following sequence – 1st line using eculizumab for rapid efficacy and stabilization without effect on the acquired immune system followed by satrilizumab (long term immunomodulation). Reserve inebilizumab (immunosuppressant) for breakthrough disease and salvage the severe with AHSCBMT. In NMO, control the complement, transition to modulation, and reserve suppression – and salvage the severe with AHSCBMT.

Aberrant Phenotypes in Acute Myeloid Leukemia and Its Relationship with Prognosis and Survival: A Systematic Review and Meta-Analysis

Background: The aim of this review was to evaluate the influence of aberrant phenotypes in prognosis and survival in acute myeloid leukemia (AML) patients by multiparametric flow cytometry. Materials and Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a review of PubMed, Scopus, Science Direct and Web of Science was carried out through 1998 to 2016, conducted by two reviewers independently, evaluating titles, abstracts and full-texts of the selected studies. Results: Ten studies were included on this review, in which the aberrant phenotype expression of 17 markers were detected in AML patients. From these, 11 aberrant phenotypes were associated with prognosis, which eight had shown negative impact on prognosis: CD7, CD56, CD15, CD2, CD3, CD90low, CD123high, CD117high, and three others were associated with good prognosis: CD19, CD98high and CD117+/CD15+. Meta-analysis showed that aberrant expression of CD56 as a poor prognostic marker with unfavorable outcomes is implicated in decreased overall survival in AML patients in 28 months (95% CI: 0.62 to 0.92). Conclusion: This was observed when there was association between CD56 expression and other prognostic factors, influencing on patients' management care and treatment.

Emerging drugs for the treatment of neuromyelitis optica

INTRODUCTION

Evidence-based treatment options for neuromyelitis optica spectrum disorders (NMOSD) patients are beginning to enter the market. Where previously, there was only the exclusive use of empiric and off-label immunosuppressants in this rare and devastating central nervous system autoimmune disease.

AREAS COVERED

In accordance to expanding pathogenetic insights, drugs in phase II and III clinical trials are presented in the context of the current treatment situation for acute attacks and immunopreventative strategies in NMOSD. Some such drugs are the 2019-approved complement inhibitor eculizumab, other compounds in late development include its modified successor ravulizumab, IL-6 receptor antibody satralizumab, CD19 targeting antibody inebilizumab and the TACI-Fc fusion protein telitacicept.

EXPERT OPINION

Moving from broad immunosuppression to tailored treatment strategies, the prospects for efficient NMOSD therapy are positive. For the first time in this disease, class I treatment evidence is available, but long-term data will be necessary to confirm the overall promising study results of the compounds close to approval. While drug development still centers around AQP4 antibody seropositive patients, current and future research requires consideration of possible diverging treatment demands for the smaller group of seronegative patients and patients with presence of MOG antibodies.

Patients with systemic lupus erythematosus show increased proportions of CD19+CD20- B cells and secretion of related autoantibodies

BACKGROUND

At present, anti-CD20 monoclonal antibody treatments targeting systemic lupus erythematosus (SLE) are complex, variable, and often have disappointing outcomes. High levels of programmed cell death-1 (PD-1) and its ligands (PD-L1, PD-L2) or CD80/CD86 on B cell surfaces are markers of increased B cell activity. However, their expression levels on CD19⁺CD20^+/- B cells and their clinical significance for SLE dynamics have not been carefully investigated.

METHODS

Flow cytometry was used to detect the expression levels of PD-1, PD-L1, PD-L2, CD80, and CD86 on CD19⁺CD20^+/- B cells in peripheral blood from SLE patients and healthy controls (HCs). The amount of anti-dsDNA and immunoglobin G (IgG) secreted by CD19⁺CD20^+/- B cells was measured by enzyme-linked immunosorbent assay.

RESULTS

CD19⁺CD20^- B cell frequency was significantly higher in SLE patients than in HCs (P < 0.001), and was positively correlated with disease activity. In SLE patients, frequencies of PD-1, PD-L1, PD-L2, and CD86 on CD19⁺CD20^- B cells were significantly higher than CD19⁺CD20⁺ B cells (P ≤ 0.002) and were significantly correlated with individual laboratory and clinically based parameters (P < 0.05). In vitro tests, we found that the levels of anti-dsDNA and IgG secreted by CD19⁺CD20^- B cells from patients with SLE were significantly higher than the HC group (P < 0.05).

CONCLUSIONS

We found abnormal frequency of CD19⁺CD20^- B cells and increased expression of surface markers on these cells from SLE patients. And the CD19⁺CD20^- B cells had the ability to proliferate and secrete anti-dsDNA and IgG. Additionally, our results suggested that CD19⁺CD20^- B cells from SLE patients may be the activated B cells and caused poor efficacy of rituximab. Key Points • CD19⁺CD20^- B cell frequencies were significantly higher in SLE patients. • Frequencies of PD-1 and its ligands on CD19⁺CD20^- B cells increased significantly in SLE patients. • CD19⁺CD20^- B cells in SLE patients had the ability to secrete anti-dsDNA and IgG. • CD19⁺CD20^- B cells in SLE patients may be the activated B cells and caused poor efficacy of rituximab.

Autoimmune Pathology in Myasthenia Gravis Disease Subtypes Is Governed by Divergent Mechanisms of Immunopathology

Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.

The Study of Correlation Between Serum Vitamin D3 Concentrations and HBV DNA Levels and Immune Response in Chronic Hepatitis Patients

Chronic hepatitis B (CHB) is a common chronic disease. Previous studies have shown a link between 25-hydroxyvitamin D₃ (vitamin D₃) concentration and liver disease. Hepatitis B virus (HBV) infection has been attributed to the inappropriate functioning of cell-mediated immunity. However, the effects of vitamin D₃, immune cell, and HBeAg status on HBV viral load in CHB patients are still unclear. We investigated the relationship between the serum concentration of vitamin D₃, percentage of immune cells in peripheral blood, and the HBV viral load of CHB patients. Sixty CHB patients were recruited, and their blood samples were collected and analyzed. Vitamin D level was measured using a chemiluminescence assay. A level of 30 ng/mL or above was defined as a vitamin D₃ sufficiency. We assigned vitamin D₃ status as either normal (≥30 ng/mL), insufficient (20-30 ng/mL), or deficient (<20 ng/mL). T-lymphocyte and B-lymphocyte surface markers in peripheral blood were detected using flow cytometry. The factors associated with HBV viral load were analyzed using univariate and multivariate-adjusted models. The mean serum vitamin D₃ concentration in the subjects was 20.9±5.6 ng/mL. Up to 88.3% of the patients were either deficient in or had insufficient vitamin D₃. The gender, BMI, hepatitis B surface antigen levels, and ALT levels were significantly related to serum vitamin D₃ levels. Serum vitamin D₃ concentration, HBe status, HBs levels, ALT, and AST levels showed a statistically significant correlation with the HBV DNA levels. Serum vitamin D₃ concentrations and hepatitis B surface antigen levels were strongly correlated with HBV DNA levels. Vitamin D₃ levels were significantly associated with CD19 numbers (β:-6.2, 95% CI: -10.5). In multivariate analysis, vitamin D₃ levels in the deficient and insufficient groups, and the CD8, HBeAg, and WBC counts were significantly associated with HBV DNA levels. In the immune tolerance phase of HBeAg-negative chronic HBV infection, vitamin D₃ may be a modulator of immune function via CD8, CD19, and HBV DNA.

B cell checkpoints in autoimmune rheumatic diseases

B cells have important functions in the pathogenesis of autoimmune diseases, including autoimmune rheumatic diseases. In addition to producing autoantibodies, B cells contribute to autoimmunity by serving as professional antigen-presenting cells (APCs), producing cytokines, and through additional mechanisms. B cell activation and effector functions are regulated by immune checkpoints, including both activating and inhibitory checkpoint receptors that contribute to the regulation of B cell tolerance, activation, antigen presentation, T cell help, class switching, antibody production and cytokine production. The various activating checkpoint receptors include B cell activating receptors that engage with cognate receptors on T cells or other cells, as well as Toll-like receptors that can provide dual stimulation to B cells via co-engagement with the B cell receptor. Furthermore, various inhibitory checkpoint receptors, including B cell inhibitory receptors, have important functions in regulating B cell development, activation and effector functions. Therapeutically targeting B cell checkpoints represents a promising strategy for the treatment of a variety of autoimmune rheumatic diseases.

[Results of a phase 1 clinical study of anti-CD20 monoclonal antibody (BCD-132): pharmacokinetics, pharmacodynamics and safety]

AIM

To study the pharmacokinetics, pharmacodynamics, and immunogenicity of two intravenous dosing regimens of the new anti-B-cells drug BCD-132 (JSC BIOCAD, Russia) at ascending doses in patients with remitting multiple sclerosis.

MATERIAL AND METHODS

Twenty-four patients with multiple sclerosis were sequentially randomized in the multicenter open-label uncontrolled multicohort phase I study (3+3 design) and assigned to 4 cohorts (8 groups). Patients in each cohort received an intravenous infusion of BCD-132 at a predefined dose ranging from 100 to 1000 mg based on the planned algorithm of dose escalation if no dose-limiting toxicities occurred.

RESULTS

The assessment of the number of cells positive for the main B-cell antigens over time demonstrated a direct effect of BCD-132 on B lymphocytes when used at a wide range of doses (100 to 1000 mg) in patients with remitting multiple sclerosis. No significant variation of the number of T-cells was observed, which clearly proves strict specificity of BCD-132 exclusively to B lymphocytes.

CONCLUSION

BCD-132 has an expected pharmacodynamic effect of long-term depletion of CD19⁺ and CD20⁺ B lymphocytes and an acceptable safety profile when used to treat patients with remitting multiple sclerosis at all tested doses.

General principles and escalation options of immunotherapy in autoantibody-associated disorders of the CNS

Autoimmune diseases associated with antineuronal and antiglial autoantibodies (Abs) is one of the most rapidly expanding research fields in clinical neuroimmunology, with more than 30 autoantibodies described so far. Being associated with a wide range of clinical presentations these syndromes can be diagnostically challenging. Surface or intracellular antigen localizations are crucial for the treatment response and outcome. In the latter Abs are mostly of paraneoplastic cause and tumor management should be performed as soon as possible in order to stop peripheral antigen stimulation. Immunotherapy should be started early in both groups, before irreversible neuronal loss occurs. Despite serious prognosis, aggressive therapeutic approaches can be effective in many cases. In this article we review main pathogenic mechanisms leading to Abs-related syndromes and describe standard as well as emerging strategies of immunotherapy, including tocilizumab and bortezomib. Several special therapeutic approaches will be illustrated by clinical cases recently treated in our department.

Immunotherapy with Monoclonal Antibodies in Lung Cancer of Mice: Oxidative Stress and Other Biological Events

Background: Lung cancer (LC) is a major leading cause of death worldwide. Immunomodulators that target several immune mechanisms have proven to reduce tumor burden in experimental models through induction of the immune microenvironment. We hypothesized that other biological mechanisms may also favor tumor burden reduction in lung cancer-bearing mice treated with immunomodulators. Methods: Tumor weight, area, T cells and tumor growth (immunohistochemistry), oxidative stress, apoptosis, autophagy, and signaling (NF-κB and sirtuin-1) markers were analyzed (immunoblotting) in subcutaneous tumor of BALB/c mice injected with LP07 adenocarcinoma cells treated with monoclonal antibodies (CD-137, CTLA-4, PD-1, and CD-19, N = 9/group) and non-treated control animals. Results: Compared to non-treated cancer mice, in tumors of monoclonal-treated animals, tumor area and weight and ki-67 were significantly reduced, while T cell counts, oxidative stress, apoptosis, autophagy, activated p65, and sirtuin-1 markers were increased. Conclusions: Immunomodulators elicited a reduction in tumor burden (reduced tumor size and weight) through decreased tumor proliferation and increased oxidative stress, apoptosis, autophagy, and signaling markers, which may have interfered with the immune profile of the tumor microenvironment. Future research should be devoted to the elucidation of the specific contribution of each biological mechanism to the reduced tumor burden.

Neuroimmunology - the past, present and future

Neuroimmunology as a separate discipline has its roots in the fields of neurology, neuroscience and immunology. Early studies of the brain by Golgi and Cajal, the detailed clinical and neuropathology studies of Charcot and Thompson's seminal paper on graft acceptance in the central nervous system, kindled a now rapidly expanding research area, with the aim of understanding pathological mechanisms of inflammatory components of neurological disorders. While neuroimmunologists originally focused on classical neuroinflammatory disorders, such as multiple sclerosis and infections, there is strong evidence to suggest that the immune response contributes to genetic white matter disorders, epilepsy, neurodegenerative diseases, neuropsychiatric disorders, peripheral nervous system and neuro-oncological conditions, as well as ageing. Technological advances have greatly aided our knowledge of how the immune system influences the nervous system during development and ageing, and how such responses contribute to disease as well as regeneration and repair. Here, we highlight historical aspects and milestones in the field of neuroimmunology and discuss the paradigm shifts that have helped provide novel insights into disease mechanisms. We propose future perspectives including molecular biological studies and experimental models that may have the potential to push many areas of neuroimmunology. Such an understanding of neuroimmunology will open up new avenues for therapeutic approaches to manipulate neuroinflammation.

Neuronanotechnology for brain regeneration

Identifying and harnessing regenerative pathways while suppressing the growth-inhibiting processes of the biological response to injury is the central goal of stimulating neurogenesis after central nervous system (CNS) injury. However, due to the complexity of the mature CNS involving a plethora of cellular pathways and extracellular cues, as well as difficulties in accessibility without highly invasive procedures, clinical successes of regenerative medicine for CNS injuries have been extremely limited. Current interventions primarily focus on stabilization and mitigation of further neuronal death rather than direct stimulation of neurogenesis. In the past few decades, nanotechnology has offered substantial innovations to the field of regenerative medicine. Their nanoscale features allow for the fine tuning of biological interactions for enhancing drug delivery and stimulating cellular processes. This review gives an overview of nanotechnology applications in CNS regeneration organized according to cellular and extracellular targets and discuss future directions for the field.

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.

Placing CD20-targeted B cell depletion in multiple sclerosis therapeutic scenario: Present and future perspectives

Multiple sclerosis (MS) is an acquired demyelinating disease of the central nervous system (CNS) that traditionally has been considered to be mediated primarily by T cells. Increasing evidence, however, suggests the fundamental role of B cells in the pathogenesis and development of the disease. Recently, anti-CD20 B cell-based therapies have demonstrated impressive and somewhat surprising results in MS, showing profound anti-inflammatory effects with a favorable risk-benefit ratio. Moreover, for the first time in the MS therapeutic scenario, the anti-CD20 monoclonal antibody ocrelizumab has been granted for the treatment of the primary progressive form of the disease. In this review, we provide a brief overview about anti-CD20 B cell-based therapies in MS, in the perspective of their influence on the future management of the disease, and of their possible positioning in a new wider therapeutic scenario.

Reduced lung cancer burden by selective immunomodulators elicits improvements in muscle proteolysis and strength in cachectic mice

Identification of to what extent tumor burden influences muscle mass independently of specific treatments for cancer-cachexia remains to be elucidated. We hypothesized that reduced tumor burden by selective treatment of tumor with immunomodulators may exert beneficial effects on muscle wasting and function in mice. Body and muscle weight, grip strength, physical activity, muscle morphometry, apoptotic nuclei, troponin-I systemic levels, interleukin-6, proteolytic markers, and tyrosine release, and apoptosis markers were determined in diaphragm and gastrocnemius muscles of lung cancer (LP07 adenocarcinoma cells) mice (BALB/c) treated with monoclonal antibodies (mAbs), against immune check-points and pathways (CD-137, cytotoxic T-lymphocyte associated protein-4, programed cell death-1, and CD-19; N = 10/group). Nontreated lung cancer cachectic mice were the controls. T and B cell numbers and macrophages were counted in tumors of both mouse groups. Compared to nontreated cachectic mice, in the mAbs-treated animals, T cells increased, no differences in B cells or macrophages, the variables final body weight, body weight and grip strength gains significantly improved. In diaphragm and gastrocnemius of mAbs-treated cachectic mice, number of apoptotic nuclei, tyrosine release, proteolysis, and apoptosis markers significantly decreased compared to nontreated cachectic mice. Systemic levels of troponin-I significantly decreased in treated cachectic mice compared to nontreated animals. We conclude that reduced tumor burden as a result of selective treatment of the lung cancer cells with immunomodulators elicits per se beneficial effects on muscle mass loss through attenuation of several biological mechanisms that lead to increased protein breakdown and apoptosis, which translated into significant improvements in limb muscle strength but not in physical activity parameters.

Neuroinflammation and B-Cell Phenotypes in Cervical and Lumbosacral Regions of the Spinal Cord in Experimental Autoimmune Encephalomyelitis in the Absence of Pertussis Toxin

OBJECTIVES

The active experimental autoimmune encephalomyelitis (EAE) model is often initiated using myelin oligodendrocyte glycoprotein (MOG) immunization followed by pertussis toxin (PTX) to study multiple sclerosis. However, PTX inactivates G protein-coupled receptors, and with increasing knowledge of the role that various G protein-coupled receptors play in immune homeostasis, it is valuable to establish neuroimmune endpoints for active EAE without PTX.

METHODS

Female C57BL/6 mice were immunized with MOG35-55 peptide in Complete Freund's Adjuvant and neuroinflammation, including central nervous system B-cell infiltration, was compared to saline-injected mice. Since it was anticipated that disease onset would be slower and less robust than EAE in the presence of PTX, both cervical and lumbosacral sections of the spinal cord were evaluated.

RESULTS

Immunohistochemical analysis showed that EAE without PTX induced immune infiltration, CCL2 and VCAM-1 upregulation. Demyelination in the cervical region correlated with the infiltration of CD19+ B cells in the cervical region. There was upregulation of IgG, CD38, and PDL1 on B cells in cervical and lumbosacral regions of the spinal cord in EAE without PTX. Interestingly, IgG was expressed predominantly by CD19- cells.

CONCLUSIONS

These data demonstrate that many neuroimmune endpoints are induced in EAE without PTX and although clinical disease is mild, this can be used as an autoimmune model when PTX inactivation of G protein-coupled receptors is not desired.

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.

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

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