Anti-CD20 monoclonal antibodies in multiple sclerosis

Preclinical specificity & activity of a fully human 41BB-expressing anti-CD19 CART- therapy for treatment-resistant autoimmune disease

Over 4% of the global population is estimated to live with autoimmune disease, necessitating immunosuppressive treatment that is often chronic, not curative, and carries associated risks. B cells have emerged as key players in disease pathogenesis, as evidenced by partial responsiveness to B cell depletion by antibody-based therapies. However, these treatments often have transient effects due to incomplete depletion of tissue-resident B cells. Chimeric antigen receptor (CAR) T cells targeting B cells have demonstrated efficacy in refractory systemic lupus erythematosus. To this end, we developed an anti-CD19 CAR T cell product candidate, CABA-201, containing a clinically evaluated fully human CD19 binder (IC78) with a 4-1BB costimulatory domain and CD3 zeta stimulation domain for treatment refractory autoimmune disease. Here, we demonstrate specific cytotoxic activity of CABA-201 against CD19+ Nalm6 cells with no off-target effects on primary human cells. Novel examination of CABA-201 generated from primary T cells from multiple patients with autoimmune disease displayed robust CAR surface expression and effective elimination of the intended target autologous CD19+ B cells in vitro. Together, these findings support the tolerability and activity of CABA-201 for clinical development in patients with autoimmune disease.

Exploring the future of SARS-CoV-2 treatment after the first two years of the pandemic: A comparative study of alternative therapeutics

One of the most pressing challenges associated with SARS-CoV-2 treatment is the emergence of new variants that may be more transmissible, cause more severe disease, or be resistant to current treatments and vaccines. The emergence of SARS-CoV-2 has led to a global pandemic, resulting in millions of deaths worldwide. Various strategies have been employed to combat the virus, including neutralizing monoclonal antibodies (mAbs), CRISPR/Cas13, and antisense oligonucleotides (ASOs). While vaccines and small molecules have proven to be an effective means of preventing severe COVID-19 and reducing transmission rates, the emergence of new virus variants poses a challenge to their effectiveness. Monoclonal antibodies have shown promise in treating early-stage COVID-19, but their effectiveness is limited in severe cases and the emergence of new variants may reduce their binding affinity. CRISPR/Cas13 has shown potential in targeting essential viral genes, but its efficiency, specificity, and delivery to the site of infection are major limitations. ASOs have also been shown to be effective in targeting viral RNA, but they face similar challenges to CRISPR/Cas13 in terms of delivery and potential off-target effects. In conclusion, a combination of these strategies may provide a more effective means of combating SARS-CoV-2, and future research should focus on improving their efficiency, specificity, and delivery to the site of infection. It is evident that the continued research and development of these alternative therapies will be essential in the ongoing fight against SARS-CoV-2 and its potential future variants.

B cell-directed therapies: a new era in Multiple Sclerosis treatment

Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS) that often progresses to severe disability. Previous studies have highlighted the role of T cells in disease pathophysiology; however, the success of B-cell-targeted therapies has led to an increased interest in how B cells contribute to disease immunopathology. In this review, we summarize evidence of B-cell involvement in MS disease mechanisms, starting with pathology and moving on to review aspects of B cell immunobiology potentially relevant to MS. We describe current theories of critical B cell contributions to the inflammatory CNS milieu in MS, namely (i) production of autoantibodies, (ii) antigen presentation, (iii) production of proinflammatory cytokines (bystander activation), and (iv) EBV involvement. In the second part of the review, we summarize medications that have targeted B cells in patients with MS and their current position in the therapeutic armamentarium based on clinical trials and real-world data. Covered therapeutic strategies include the targeting of surface molecules such as CD20 (rituximab, ocrelizumab, ofatumumab, ublituximab) and CD19 (inebilizumab), and molecules necessary for B-cell activation such as B cell activating factor (BAFF) (belimumab) and Bruton's Tyrosine Kinase (BTK) (evobrutinib). We finally discuss the use of B-cell-targeted therapeutics in pregnancy.

Bruton's Tyrosine Kinase Inhibitors: A New Generation of Promising Agents for Multiple Sclerosis Therapy

B cells play a central role in the pathogenesis of multiple sclerosis (MS), as demonstrated through the success of various B cell-depleting monoclonal antibodies. Bruton’s tyrosine kinase (BTK) is a critical molecule in intracellular signaling from the receptor of B cells and receptors expressed in the cells of the innate immune system. BTK inhibitors may be a non-cell-depleting alternative to B cell modulation. In this review, the structure, signaling, and roles of BTK are reviewed among the different inhibitors assayed in animal models of MS and clinical trials.

Mechanistic insights into the role of B cells in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease epitomized by severe inflammation that induces tendon, cartilage, and bone damage over time. Although different types of cells undertake pathogenic functions in RA, the B cell's significant involvement has increasingly been known following the development of rheumatoid factor and it has been re-emphasized in recent years. Therefore, the rheumatoid factors and anti-cyclic citrullinated peptide antibodies are well-known indications of infection and clinical manifestations, and that they can precede the development of illness by several years. The emergence of rituximab a B cell reducing chimeric antidote in 1997 and 1998 transformed B-cell-targeted therapy for inflammatory disorder from a research hypothesis to a functional fact. Ever since, several autoantibody-related conditions were addressed, including the more intriguing indications of effectiveness seen in rheumatoid arthritis patients. Numerous types of B-cell-targeted compounds are currently being researched. From the beginning, one of the primary goals of B-cell therapy was to reinstate some kind of immune tolerance. While B cells have long been recognized as essential autoantibody producers, certain antibody-independent functions and usefulness as a key targeted therapy were not recognized until recently. The knowledge of B cells' diverse physical and pathogenic roles in autoimmune diseases is growing. As a result, the number of successful agents targeting the B cell complex is becoming more ubiquitous. Therefore, in this article, we explore fresh perspectives upon the roles of B cells in arthritis treatment, as well as new evidence regarding the effectiveness of B lymphocytes reduction and the therapeutic outcome of biological markers.

Ectopic lymphoid follicles in progressive multiple sclerosis: From patients to animal models

Ectopic lymphoid follicles (ELFs), resembling germinal centre‐like structures, emerge in a variety of infectious and autoimmune and neoplastic diseases. ELFs can be found in the meninges of around 40% of the investigated progressive multiple sclerosis (MS) post‐mortem brain tissues and are associated with the severity of cortical degeneration and clinical disease progression. Of predominant importance for progressive neuronal damage during the progressive MS phase appears to be meningeal inflammation, comprising diffuse meningeal infiltrates, B‐cell aggregates and compartmentalized ELFs. However, the absence of a uniform definition of ELFs impedes reproducible and comparable neuropathological research in this field. In this review article, we will first highlight historical aspects and milestones around the discovery of ELFs in the meninges of progressive MS patients. In the next step, we discuss how animal models may contribute to an understanding of the mechanisms underlying ELF formation. Finally, we summarize challenges in investigating ELFs and propose potential directions for future research.

B cells in multiple sclerosis - from targeted depletion to immune reconstitution therapies

Increasing evidence indicates the involvement of B cells in the pathogenesis of multiple sclerosis (MS), but their precise roles are unclear. In this Review, we provide an overview of the development and physiological functions of B cells and the main mechanisms through which B cells are thought to contribute to CNS autoimmunity. In MS, abnormalities of B cell function include pro-inflammatory cytokine production, defective B cell regulatory function and the formation of tertiary lymphoid-like structures in the CNS, which are the likely source of abnormal immunoglobulin production detectable in the cerebrospinal fluid. We also consider the hypothesis that Epstein-Barr virus (EBV) is involved in the B cell overactivation that leads to inflammatory injury to the CNS in MS. We also review the immunological effects - with a focus on the effects on B cell subsets - of several successful therapeutic approaches in MS, including agents that selectively deplete B cells (rituximab, ocrelizumab and ofatumumab), agents that less specifically deplete lymphocytes (alemtuzumab and cladribine) and autologous haematopoietic stem cell transplantation, in which the immune system is unselectively ablated and reconstituted. We consider the insights that these effects on B cell populations provide and their potential to further our understanding and targeting of B cells in MS.

Anti-CD20 Agents for Multiple Sclerosis: Spotlight on Ocrelizumab and Ofatumumab

Until recently, in the pathogenesis of Multiple Sclerosis (MS), the contribution of B cells has been largely underestimated, and the disease was considered a T-cell-mediated disorder. However, newer evidence shows that B cells play a crucial role in the pathogenesis of MS via antigen-driven autoantibody responses and through the cross regulation of T-helper cells. As B cells express the surface molecule CD20 at all points of differentiation, it provides a specific target for monoclonal antibodies, and the development and clinical testing of anti-CD20 antibody treatments for MS have been successful. After some observations, some small clinical trials found positive effects for the first anti-CD20 therapeutic rituximab in MS; newer agents have been specifically evaluated, resulting in the development of ocrelizumab and ofatumumab. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, was approved in March 2017 by the Food and Drug Administration (FDA) and is also the first proven therapy to reduce disability progression in primary progressive MS. This is particularly significant considering that disease-modifying treatment options are few for both primary and secondary progressive MS. Ofatumumab, a fully human anti-CD20 monoclonal antibody, that binds a distinct epitope, has been further investigated in phase 3 trials for relapsing forms of MS. In this review, we discuss in detail these two anti-CD20 agents and their advent for treatment of MS.

Anti-inflammatory and Neuroprotective Agents in Clinical Trials for CNS Disease and Injury: Where Do We Go From Here?

Neurological disorders are major contributors to death and disability worldwide. The pathology of injuries and disease processes includes a cascade of events that often involve molecular and cellular components of the immune system and their interaction with cells and structures within the central nervous system. Because of this, there has been great interest in developing neuroprotective therapeutic approaches that target neuroinflammatory pathways. Several neuroprotective anti-inflammatory agents have been investigated in clinical trials for a variety of neurological diseases and injuries, but to date the results from the great majority of these trials has been disappointing. There nevertheless remains great interest in the development of neuroprotective strategies in this arena. With this in mind, the complement system is being increasingly discussed as an attractive therapeutic target for treating brain injury and neurodegenerative conditions, due to emerging data supporting a pivotal role for complement in promoting multiple downstream activities that promote neuroinflammation and degeneration. As we move forward in testing additional neuroprotective and immune-modulating agents, we believe it will be useful to review past trials and discuss potential factors that may have contributed to failure, which will assist with future agent selection and trial design, including for complement inhibitors. In this context, we also discuss inhibition of the complement system as a potential neuroprotective strategy for neuropathologies of the central nervous system.

Tissue Transglutaminase Appears in Monocytes and Macrophages but Not in Lymphocytes in White Matter Multiple Sclerosis Lesions

Leukocyte infiltration is an important pathological hallmark of multiple sclerosis (MS) and is therefore targeted by current MS therapies. The enzyme tissue transglutaminase (TG2) contributes to monocyte/macrophage migration and is present in MS lesions and could be a potential therapeutic target. We examined the cellular identity of TG2-expressing cells by immunohistochemistry in white matter lesions of 13 MS patients; 9 active and chronic active lesions from 4 patients were analyzed in detail. In these active MS lesions, TG2 is predominantly expressed in leukocytes (CD45⁺) but not in cells of the lymphocyte lineage, that is, T cells (CD3⁺) and B cells (CD20⁺). In general, cells of the monocyte/macrophage lineage (CD11b⁺ or CD68⁺) are TG2⁺ but no further distinction could be made regarding pro- or anti-inflammatory macrophage subtypes. In conclusion, TG2 is abundantly present in cells of the monocyte/macrophage lineage in active white matter MS lesions. We consider that TG2 can play a role in MS as it is associated with macrophage infiltration into the CNS. As such, TG2 potentially presents a novel target for therapeutic intervention that can support available MS therapies targeting lymphocyte infiltration.

COVID-19 in 7 multiple sclerosis patients in treatment with ANTI-CD20 therapies

BACKGROUND AND AIM

In December 2019, the first cases of SARS-CoV-2 infection were detected in Wuhan. Within two months, it had begun to spread around the world in what became an unprecedented pandemic. Patients with Multiple Sclerosis (MS) in a state of immunosuppression may be considered at risk for complications in the COVID-19 pandemic, although there is increasing evidence postulating a possible protective role of selective immunosuppression. One group of such immunosuppressants used in MS comprises the anti-CD20 monoclonal antibodies (mAbs) ocrelizumab and rituximab. Anti-CD20 mAbs bind to the surface of B cells, causing their depletion. We describe our experience in seven cases of patients with multiple sclerosis who have been affected by SARS-COV-2 (with a clinical/serological diagnosis or PCR diagnosis) and who were being treated with anti-CD20+ monoclonal antibodies.

MATERIAL AND METHODS

We review the development of patients during infection as well as the resolution of their clinical picture. We also analyze the serology status against SARS-CoV-2 after resolution of the infection.

RESULTS

Although the severity of the clinical pictures was variable, patients' development was good. Not all patients, however, developed antibodies against SARS-CoV-2.

CONCLUSIONS

Patients treated with anti-CD20+ have adequate resolution of COVID-19 despite the fact that the presence of antibodies against SARS-CoV-2 was not detected in all cases. It is possible that the presence of humoral immunity is not always necessary fora good clinical course of SARS-CoV-2 infection.

Repopulation of T, B, and NK cells following alemtuzumab treatment in relapsing-remitting multiple sclerosis

OBJECTIVE

To characterize long-term repopulation of peripheral immune cells following alemtuzumab-induced lymphopenia in relapsing-remitting MS (RRMS), with a focus on regulatory cell types, and to explore associations with clinical outcome measures.

METHODS

The project was designed as a multicenter add-on longitudinal mechanistic study for RRMS patients enrolled in CARE-MS II, CARE-MS II extension at the University of Southern California and Stanford University, and an investigator-initiated study conducted at the Universities of British Columbia and Chicago. Methods involved collection of blood at baseline, prior to alemtuzumab administration, and at months 5, 11, 17, 23, 36, and 48 post-treatment. T cell, B cell, and natural killer (NK) cell subsets, chemokine receptor expression in T cells, in vitro cytokine secretion patterns, and regulatory T cell (Treg) function were assessed. Clinical outcomes, including expanded disability status score (EDSS), relapses, conventional magnetic resonance imaging (MRI) measures, and incidents of secondary autoimmunity were tracked.

RESULTS

Variable shifts in lymphocyte populations occurred over time in favor of CD4+ T cells, B cells, and NK cells with surface phenotypes characteristic of regulatory subsets, accompanied by reduced ratios of effector to regulatory cell types. Evidence of increased Treg competence was observed after each treatment course. CD4+ and CD8+ T cells that express CXCR3 and CCR5 and CD8+ T cells that express CDR3 and CCR4 were also enriched after treatment, indicating heightened trafficking potential in activated T cells. Patterns of repopulation were not associated with measures of clinical efficacy or secondary autoimmunity, but exploratory analyses using a random generalized estimating equation (GEE) Poisson model provide preliminary evidence of associations between pro-inflammatory cell types and increased risk for gadolinium (Gd+) enhancing lesions, while regulatory subsets were associated with reduced risk. In addition, the risk for T2 lesions correlated with increases in CD3+CD8+CXCR3+ cells.

CONCLUSIONS

Lymphocyte repopulation after alemtuzumab treatment favors regulatory subsets in the T cell, B cell, and NK cell compartments. Clinical efficacy may reflect the sum of interactions among them, leading to control of potentially pathogenic effector cell types. Several immune measures were identified as possible biomarkers of lesion activity. Future studies are necessary to more precisely define regulatory and effector subsets and their contributions to clinical efficacy and risk for secondary autoimmunity in alemtuzumab-treated patients, and to reveal new insights into mechanisms of immunopathogenesis in MS.

TRIAL REGISTRATION

Parent trials for this study are registered with ClinicalTrials.gov: CARE-MS II: NCT00548405, CARE-MS II extension: NCT00930553 and ISS: NCT01307332.

Molecular Effects of FDA-Approved Multiple Sclerosis Drugs on Glial Cells and Neurons of the Central Nervous System

Multiple sclerosis (MS) is characterized by peripheral and central inflammatory features, as well as demyelination and neurodegeneration. The available Food and Drug Administration (FDA)-approved drugs for MS have been designed to suppress the peripheral immune system. In addition, however, the effects of these drugs may be partially attributed to their influence on glial cells and neurons of the central nervous system (CNS). We here describe the molecular effects of the traditional and more recent FDA-approved MS drugs Fingolimod, Dimethyl Fumarate, Glatiramer Acetate, Interferon-β, Teriflunomide, Laquinimod, Natalizumab, Alemtuzumab and Ocrelizumab on microglia, astrocytes, neurons and oligodendrocytes. Furthermore, we point to a possible common molecular effect of these drugs, namely a key role for NFκB signaling, causing a switch from pro-inflammatory microglia and astrocytes to anti-inflammatory phenotypes of these CNS cell types that recently emerged as central players in MS pathogenesis. This notion argues for the need to further explore the molecular mechanisms underlying MS drug action.

Lower risk of multiple sclerosis in patients with chronic hepatitis C: a nationwide population-based registry study

Background

Multiple sclerosis (MS) is an immune-mediated neurological disease that causes demyelination. The etiology is unknown, but patients with a previous viral infection, such as Epstein–Barr virus, have been shown to be at a higher risk of developing MS. In contrast, people living with HIV have a lower risk of developing MS. Hepatitis C virus (HCV) mainly infects the liver, but patients with HCV can experience several extrahepatic manifestations and studies have shown an association with several autoimmune conditions such as neuropathy and myelitis. The present study aimed to investigate the risk of MS in patients with chronic HCV infection compared with matched comparators.

Methods

Patients were identified using the nationwide Swedish inpatient (2001–2013) and outpatient care registers (2001–2013) for HCV (B18.2) and MS (G35) according to the International Classification of Diseases-10. Up to five comparators (matched on age/sex/place of residency) were drawn from the general population for each HCV patient. Follow-up started at the first HCV visit from 2001 and the patients’ accrued person-time until death, emigration or 31 December 2013. Risk of MS diagnosis was calculated as standardized incidence ratio (SIR) with 95% confidence intervals (CIs).

Results

HCV patients were at lower risk of MS diagnosis (SIR 0.37; 95% CI 0.26–0.50). The incidence of MS during the study in the HCV cohort was 0.087% compared with 0.27% in the matched comparator cohort.

Conclusion

Surprisingly, these data suggest HCV patients to have a lower risk of MS diagnosis.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09397-8) contains supplementary material, which is available to authorized users.

Rituximab vs placebo induction prior to glatiramer acetate monotherapy in multiple sclerosis

OBJECTIVE

To examine whether rituximab induction followed by glatiramer acetate (GA) monotherapy is more effective than GA alone for the treatment of relapsing multiple sclerosis with active disease.

METHODS

This was a single-center, double-blind, placebo-controlled study. Fifty-five participants were randomly assigned (1:1 ratio) to either rituximab (R-GA) or placebo (P-GA) induction, followed by GA therapy initiated in all participants. Participants were followed up to 3 years. The primary endpoint was the number of participants with no evidence of disease activity (NEDA): those without relapse, new MRI lesions, and sustained change in disability.

RESULTS

Twenty-eight and 27 participants received rituximab and placebo induction, respectively, with one participant in each arm withdrawing before 6-month MRI. There were no significant differences in baseline characteristics. At end of study, 44.44% of R-GA participants demonstrated NEDA vs 19.23% of P-GA participants (p = 0.049). Treatment failed for a smaller proportion of R-GA participants (37.04% R-GA vs 69.23% P-GA, p = 0.019), and time to treatment failure was longer (23.32 months R-GA vs 11.29 months P-GA, p = 0.027). Fewer participants in the R-GA arm had new lesions (25.93% R-GA vs 61.54% P-GA, p = 0.009), and there were fewer new T2 lesions (0.48 R-GA vs 1.96 P-GA, p = 0.027). Probability of demonstrating NEDA in the R-GA arm returned to baseline within the study period. There were no differences in adverse events.

CONCLUSIONS

Induction therapy with rituximab followed by GA may provide superior efficacy in the short term than GA alone in relapsing multiple sclerosis, but this benefit appears to wane within the study period. Larger studies are needed to assess sustainability of results.

CLINICALTRIALSGOV IDENTIFIER

NCT01569451.

Efficacy and safety of autologous hematopoietic stem-cell transplantation in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Autologous hematopoietic stem-cell transplantation (AHSCT) has been utilized as a treatment option for multiple sclerosis (MS) since 1995. However, this procedure has not been widely implemented in clinical practice owing to its mortality risk. Here, we conduct a meta-analysis to evaluate the long-term efficacy and safety of AHSCT in MS treatment, aiming to optimize the benefit/risk ratio of this therapeutic strategy.

METHODS

We searched the PubMed Web site and clinicaltrials.gov databases. The efficacy endpoints were progression-free survival (PFS) and disease activity-free survival. The safety outcomes were transplant-related mortality (TRM) and overall deaths.

RESULTS

Eighteen eligible studies with a total of 732 participants were enrolled. The PFS was 75% (95% CI, 0.69-0.81), and the estimate of disease activity-free survival was 61% with 48-month follow-up. Subgroups analysis showed that low- and intermediate-intensity regimens were associated with higher PFS 80%. Relapsing remitting MS (RRMS) benefited more from AHSCT than other MS subtypes with PFS 85%. Patients with Gd+ lesions at baseline MRI responded better to AHSCT with PFS 77%. The estimate of TRM was 1.34% (95% CI, 0.39-2.30), and the overall mortality was 3.58%. TRM was significantly higher in high-intensity regimen studies (3.13%) and in older studies (1.93%) performed before 2006.

CONCLUSIONS

This meta-analysis provides evidences that AHSCT can induce long-term remissions for MS patients with a high degree of safety. We indicate low- and intermediate-intensity regimens and RRMS patients with the presence of Gd+ lesions at baseline MRI can obtain the optimal benefit/risk ratio from AHSCT.

Production of IL-35 by Bregs is mediated through binding of BATF-IRF-4-IRF-8 complex to il12a and ebi3 promoter elements

IL-10 and IL-35 suppress excessive immune responses and therapeutic strategies are being developed to increase their levels in autoimmune diseases. In this study, we sought to identify major cell types that produce both cytokines in-vivo and to characterize mechanisms that regulate their production. Experimental autoimmune uveitis (EAU) is a CNS autoimmune disease that serves as model of human uveitis. We induced EAU in C57BL/6J mice and investigated whether T cells, B lymphocytes, or myeloid cells are the major producers of IL-10 or IL-35 in blood, lymph nodes (LNs), spleen, and at the site of ocular inflammation, the neuroretina. Analysis of these tissues identified B cells as the major producers of IL-10 and IL-35 in-vivo. Compared to regulatory T cells (Tregs), IL-10- or IL-35-producing regulatory B cells (Bregs) are substantially expanded in blood, LNs, spleen, and retina of mice with EAU. We performed EMSA and chromatin immunoprecipitation (ChIP) assays on activated B cells stimulated with IL-35 or TLR agonists. We found that BATF, IFN regulatory factor (IRF)-4, and IRF-8 transcription factors were recruited and bound to AP1-IRF-composite elements (AICEs) of il12a, ebi3, and/or il10 loci, suggesting their involvement in regulating IL-10 and IL-35 transcriptional programs of B cells. Showing that B cells are major source of IL-10 and IL-35 in-vivo and identifying transcription factors that contribute to IL-10 and IL-35 expression in the activated B-cell, suggest that the BATF/IRF-4/IRF-8 axis can be exploited therapeutically to regulate physiological levels of IL-10/IL-35-Bregs and that adoptive transfer of autologous Bregs might be an effective therapy for autoimmune and neurodegenerative diseases.

Alemtuzumab for the treatment of multiple sclerosis

INTRODUCTION

Alemtuzumab is a monoclonal antibody that targets for the destruction CD52+ cells, particularly B and T cells. Alemtuzumab is approved in more than 50 countries around the world for the treatment of adult patients with relapsing remitting multiple sclerosis (MS). Areas covered: In this review, the authors summarize biological, clinical and safety data related to the use of alemtuzumab in patients with MS. The authors then provide their expert opinion on alemtuzumab and the field as of whole before providing their perspectives for the future. Expert opinion: Alemtuzumab is highly efficacious; more so than first line treatments but comparable to natalizumab. Treatment schedule makes alemtuzumab administration easy and attractive to patients. However, its safety profile makes it a choice for a very limited number of patients, in a specific disease window. As of now, a cure for MS remains elusive and there is an unmet need for a safe and highly potent agent at the level of and beyond the blood brain barrier.

Regulatory B and T lymphocytes in multiple sclerosis: friends or foes?

Current clinical experience with immunomodulatory agents and monoclonal antibodies in principle has established the benefit of depleting lymphocytic populations in relapsing–remitting multiple sclerosis (RRMS). B and T cells may exert multiple pro-inflammatory actions, but also possess regulatory functions making their role in RRMS pathogenesis much more complex. There is no clear correlation of Tregs and Bregs with clinical features of the disease. Herein, we discuss the emerging data on regulatory T and B cell subset distributions in MS and their roles in the pathophysiology of MS and its murine model, experimental autoimmune encephalomyelitis (EAE). In addition, we summarize the immunomodulatory properties of certain MS therapeutic agents through their effect on such regulatory cell subsets and their relevance to clinical outcomes.

G1m1 predominance of intrathecal virus-specific antibodies in multiple sclerosis

We have previously shown that plasmablasts of the G1m1 allotype of IgG1 are selectively enriched in the cerebrospinal fluid of G1m1/G1m3 heterozygous patients with multiple sclerosis, whereas both allotypes are equally used in neuroborreliosis. Here, we demonstrate a strong preference for the G1m1 allotype in the intrathecal humoral immune responses against measles, rubella, and varicella zoster virus in G1m1/G1m3 heterozygous multiple sclerosis patients. Conversely, intrathecally synthesized varicella zoster virus‐specific IgG1 in varicella zoster virus meningoencephalitis comprised both allotypes. This implies that G1m1 B cells are selected to the central nervous system of multiple sclerosis patients regardless of specificity and suggests that an antigen‐independent mechanism could drive the intrathecal humoral immune response.

Immunophenotype and Transcriptome Profile of Patients With Multiple Sclerosis Treated With Fingolimod: Setting Up a Model for Prediction of Response in a 2-Year Translational Study

BACKGROUND

Fingolimod is a functional sphingosine-1-phosphate antagonist approved for the treatment of multiple sclerosis (MS). Fingolimod affects lymphocyte subpopulations and regulates gene expression in the lymphocyte transcriptome. Translational studies are necessary to identify cellular and molecular biomarkers that might be used to predict the clinical response to the drug. In MS patients, we aimed to clarify the differential effects of fingolimod on T, B, and natural killer (NK) cell subsets and to identify differentially expressed genes in responders and non-responders (NRs) to treatment.

MATERIALS AND METHODS

Samples were obtained from relapsing-remitting multiple sclerosis patients before and 6 months after starting fingolimod. Forty-eight lymphocyte subpopulations were measured by flow cytometry based on surface and intracellular marker analysis. Transcriptome sequencing by next-generation technologies was used to define the gene expression profiling in lymphocytes at the same time points. NEDA-3 (no evidence of disease activity) and NEDA-4 scores were measured for all patients at 1 and 2 years after beginning fingolimod treatment to investigate an association with cellular and molecular characteristics.

RESULTS

Fingolimod affects practically all lymphocyte subpopulations and exerts a strong effect on genetic transcription switching toward an anti-inflammatory and antioxidant response. Fingolimod induces a differential effect in lymphocyte subpopulations after 6 months of treatment in responder and NR patients. Patients who achieved a good response to the drug compared to NR patients exhibited higher percentages of NK bright cells and plasmablasts, higher levels of FOXP3, glucose phosphate isomerase, lower levels of FCRL1, and lower Expanded Disability Status Scale at baseline. The combination of these possible markers enabled us to build a probabilistic linear model to predict the clinical response to fingolimod.

CONCLUSION

MS patients responsive to fingolimod exhibit a recognizable distribution of lymphocyte subpopulations and a different pretreatment gene expression signature that might be useful as a biomarker.

Reversing Autoimmunity Combination of Rituximab and Intravenous Immunoglobulin

In this concept paper, the authors present a unique and novel protocol to treat autoimmune diseases that may have the potential to reverse autoimmunity. It uses a combination of B cell depletion therapy (BDT), specifically rituximab (RTX) and intravenous immunoglobulin (IVIg), based on a specifically designed protocol (Ahmed Protocol). Twelve infusions of RTX are given in 6–14 months. Once the CD20⁺ B cells are depleted from the peripheral blood, IVIg is given monthly until B cells repopulation occurs. Six additional cycles are given to end the protocol. During the stages of B cell depletion, repopulation and after clinical recovery, IVIg is continued. Along with clinical recovery, significant reduction and eventual disappearance of pathogenic autoantibody occurs. Administration of IVIg in the post-clinical period is a crucial part of this protocol. This combination reduces and may eventually significantly eliminates inflammation in the microenvironment and facilitates restoring immune balance. Consequently, the process of autoimmunity and the phenomenon that lead to autoimmune disease are arrested, and a sustained and prolonged disease and drug-free remission is achieved. Data from seven published studies, in which this combination protocol was used, are presented. It is known that BDT does not affect check points. IVIg has functions that mimic checkpoints. Hence, when inflammation is reduced and the microenvironment is favorable, IVIg may restore tolerance. The authors provide relevant information, molecular mechanism of action of BDT, IVIg, autoimmunity, and autoimmune diseases. The focus of the manuscript is providing an explanation, using the current literature, to demonstrate possible pathways, used by the combination of BDT and IVIg in providing sustained, long-term, drug-free remissions of autoimmune diseases, and thus reversing autoimmunity, albeit for the duration of the observation.

Targeting B Cells and Plasma Cells in Autoimmune Diseases

Success with B cell depletion using rituximab has proven the concept that B lineage cells represent a valid target for the treatment of autoimmune diseases, and has promoted the development of other B cell targeting agents. Present data confirm that B cell depletion is beneficial in various autoimmune disorders and also show that it can worsen the disease course in some patients. These findings suggest that B lineage cells not only produce pathogenic autoantibodies, but also significantly contribute to the regulation of inflammation. In this review, we will discuss the multiple pro- and anti-inflammatory roles of B lineage cells play in autoimmune diseases, in the context of recent findings using B lineage targeting 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.

Humoral response in experimental autoimmune encephalomyelitis targets neural precursor cells in the central nervous system of naive rodents

Background

Neural precursor cells (NPCs) located in the subventricular zone (SVZ), a well-defined NPC niche, play a crucial role in central nervous system (CNS) homeostasis. Moreover, NPCs are involved in the endogenous reparative process both in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). However, the possibility that NPCs may be vulnerable to immune-related components may not be ruled out. Therefore, we investigated the potential affinity of myelin oligodendrocyte glycoprotein (MOG)-induced humoral response(s) to NPCs.

Methods

MOG_35–55-EAE was induced in C57BL/6 mice; blood-sampling was performed on days 17–21 (acute phase) along with a naive group and corresponding antisera (AS) were collected (EAE-AS, NAIVE-AS). The presence of anti-CNS autoantibodies was examined with western blotting. Furthermore, using the collected antisera and anti-MOG antibody (as positive control), immunohistochemistry and double immunofluorescence were implemented on normal neonatal, postnatal, and adult mouse brain sections. Targeted NPCs were identified with confocal microscopy. In vitro immunoreactivity assessment on NPCs challenged with autoantibodies was evaluated for apoptotic/autophagic activity.

Results

Western blotting verified the existence of autoantibodies in EAE mice and demonstrated bands corresponding to yet unidentified NPC surface epitopes. A dominant selective binding of EAE-AS in the subventricular zone in all age groups compared to NAIVE-AS (p < 0.001) was observed. Additionally, anti-BrdU⁺/EAE-AS⁺ colocalization was significantly higher than anti-BrdU⁺/anti-MOG⁺, a finding suggesting that the EAE humoral response colocalized with NPCs(BrdU⁺), cells that do not express MOG. Well-established NPC markers (Nestin, m-Musashi-1, Sox2, DCX, GFAP, NG2) were used to identify the distinct cell types which exhibited selective binding with EAE-AS. The findings verified that EAE-AS exerts cross-reactivity with NPCs which varies throughout the neonatal to adult stage, with a preference to cells of early developmental stages. Finally, increased expressions of Caspase 3 and Beclin 1 on NPCs were detected.

Conclusion

We provide evidence for the first time that MOG_35–55 EAE induces production of antibodies with affinity to SVZ of naive mice in three different age groups. These autoantibodies target lineage-specific NPCs as brain develops and have the potential to trigger apoptotic pathways. Thus, our findings provide indication that cross-talk between immunity and NPCs may lead to functional alteration of NPCs regarding their viability and potentially oligodendrogenesis and effective remyelination.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0995-2) contains supplementary material, which is available to authorized users.

Human Tregs Made Antigen Specific by Gene Modification: The Power to Treat Autoimmunity and Antidrug Antibodies with Precision

Human regulatory CD4⁺ T cells (Tregs) are potent immunosuppressive lymphocytes responsible for immune tolerance and homeostasis. Since the seminal reports identifying Tregs, vast research has been channeled into understanding their genesis, signature molecular markers, mechanisms of suppression, and role in disease. This research has opened the doors for Tregs as a potential therapeutic for diseases and disorders such as multiple sclerosis, type I diabetes, transplantation, and immune responses to protein therapeutics, like factor VIII. Seminal clinical trials have used polyclonal Tregs, but the frequency of antigen-specific Tregs among polyclonal populations is low, and polyclonal Tregs may risk non-specific immunosuppression. Antigen-specific Treg therapy, which uses genetically modified Tregs expressing receptors specific for target antigens, greatly mitigates this risk. Building on the principles of T-cell receptor cloning, chimeric antigen receptors (CARs), and a novel CAR derivative, called B-cell antibody receptors, our lab has developed different types of antigen-specific Tregs. This review discusses the current research and optimization of gene-modified antigen-specific human Tregs in our lab in several disease models. The preparations and considerations for clinical use of such Tregs also are discussed.

Monoclonal Antibodies in Preclinical EAE Models of Multiple Sclerosis: A Systematic Review

Monoclonal antibodies (mAb) are promising therapeutics in multiple sclerosis and multiple new candidates have been developed, hence increasing the need for some agreement for preclinical mAb studies. We systematically analyzed publications of experimental autoimmune encephalomyelitis (EAE) studies showing effects of monoclonal antibodies. A PubMed search retrieved 570 records, out of which 122 studies with 253 experiments were eligible based on experimental design, number of animals and presentation of time courses of EAE scores. Analysis of EAE models, treatment schedules, single and total doses, routes of administration, and onset of treatment from pre-immunization up to 35 days after immunization revealed high heterogeneity. Total doses ranged from 0.1 to 360 mg/kg for observation times of up to 35 days after immunization. About half of experiments (142/253) used total doses of 10-70 mg/kg. Employing this range, we tested anti-Itga4 as a reference mAb at varying schedules and got no, mild or substantial EAE-score reductions, depending on the mouse strain and onset of the treatment. The result agrees with the range of outcomes achieved in 10 reported anti-Itga4 experiments. Studies comparing low and high doses of various mAbs or early vs. late onset of treatment did not reveal dose-effect or timing-effect associations, with a tendency towards better outcomes with preventive treatments starting within the first week after immunization. The systematic comparison allows for extraction of some "common" design characteristics, which may be helpful to further assess the efficacy of mAbs and role of specific targets in preclinical models of multiple sclerosis.

IL-10-Producing B Cells Suppress Effector T Cells Activation and Promote Regulatory T Cells in Crystalline Silica-Induced Inflammatory Response In Vitro

Long-term exposure to crystalline silica leads to silicosis, which is characterized by persistent lung inflammation and lung fibrosis. Multiple immune cells have been demonstrated to participate in crystalline silica-induced immune responses. Our previous study indicated that B10 could control lung inflammation through modulating the Th balance in experimental silicosis in mice. However, the regulatory mechanism of B10 on CD4⁺ T cells is still unclear. MACS-sorted CD19⁺ B cells from the three different groups were cultured with CD4⁺ T cells either with or without transwell insert plates to evaluate the effects of B10 on CD4⁺ T cells, including Teff and Treg. B10 was eliminated by anti-CD22 application in vivo. Flow cytometry was used to test the frequencies of CD4⁺ T cells, and the expressions of the related cytokines were detected by real-time PCR and CBA. Insufficient B10 elevated the levels of proinflammatory cytokines and promoted Th responses in a way independent upon cell-cell contact in the Teff and B cell coculture system. B10 could both increase Treg activity and enhance conversion of Teff into Treg. Our findings demonstrated that B10 could affect Th responses by the release of IL-10, enhancing Treg functions and converting Teff into Treg.

Direct targeting of cancer cells with antibodies: What can we learn from the successes and failure of unconjugated antibodies for lymphoid neoplasias?

Following approval in 1997 of the anti-CD20 antibody rituximab for the treatment of B-NHL and CLL, many other unconjugated IgG1 MAbs have been tested in pre-clinical and clinical trials for the treatment of lymphoid neoplasms. Relatively few have been approved however and these are directed against a limited number of target antigens (CD20, CD52, CCR4, CD38, CD319). We review here the known biological properties of these antibodies and discuss which factors may have led to their success or may, on the contrary, limit their clinical application. Common factors of the approved MAbs are that the target antigen is expressed at relatively high levels on the neoplastic targets and their mechanism of action is mostly immune-mediated. Indeed most of these MAbs induce ADCC and phagocytosis by macrophages, and many also activate complement, leading to target cell lysis. In contrast direct cell death induction is not a common feature but may enhance efficacy in some cases. Interestingly, a key factor for the success of several MAbs appears to be their capacity to skew immunity towards an anti-tumour mode, by inhibiting/depleting suppressor cells and/or activating immune cells within the microenvironment, independently of FcγRs. We also expose here some of the strategies employed by industry to expand the clinical use of these molecules beyond their original indication. Interestingly, due to the central role of lymphocytes in the control of the immune response, several of the antibodies are now successfully used to treat many different autoimmune diseases and have also been formally approved for some of these new indications. There is little doubt that this trend will continue and that the precise mechanisms of therapeutic MAbs will be further dissected and better understood in the context of both tumour immunology and autoimmunity.