Rituximab induces clonal expansion of IgG memory B-cells in patients with inflammatory central nervous system demyelination

The pharmacological management of myelin oligodendrocyte glycoprotein-immunoglobulin G associated disease (MOGAD): an update of the literature

INTRODUCTION

Myelin oligodendrocyte glycoprotein-immunoglobulin G associated disease (MOGAD) is a clinical entity distinct from multiple sclerosis and aquaporin-4 (AQP4+)-IgG-positive neuromyelitis optica spectrum disorder. There is a lack of evidence regarding the efficacy and safety of current treatments used for MOGAD.

AREAS COVERED

In this article, the authors review the currently available literature on the pharmacological management of MOGAD. This article is based on an extensive search for articles including meta-analyses, clinical trials, systematic reviews, observational studies, case series and case reports.

EXPERT OPINION

Intravenous high-dose methylprednisolone is the most common therapy for acute attack with patients having a good treatment response. In cases with poor recovery, intravenous immunoglobulins (IVIG) or plasma-exchange proved to be effective. Maintenance therapies include mycophenolate mofetil, azathioprine, IVIG, oral corticosteroids, rituximab, and interleukin-6 receptor (IL6-R) antagonists. Rituximab is the most used drug while IL6-R antagonists emerged as an effective option for people not responding to current treatments. Larger prospective studies with longer follow-ups are needed to confirm whether the blockage of the IL6-R is an effective and safe option. Since there is no evidence of major safety issues related to the new available therapies, the authors believe that waiting for disease activity to consider a possible treatment change, is an unwise approach.

Deciphering Autoimmune Diseases: Unveiling the Diagnostic, Therapeutic, and Prognostic Potential of Immune Repertoire Sequencing

Autoimmune diseases (AIDs) are immune system disorders where the body exhibits an immune response to its own antigens, causing damage to its own tissues and organs. The pathogenesis of AIDs is incompletely understood. However, recent advances in immune repertoire sequencing (IR-seq) technology have opened-up a new avenue to study the IR. These studies have revealed the prevalence in IR alterations, potentially inducing AIDs by disrupting immune tolerance and thereby contributing to our comprehension of AIDs. IR-seq harbors significant potential for the clinical diagnosis, personalized treatment, and prognosis of AIDs. This article reviews the application and progress of IR-seq in diseases, such as multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, and type 1 diabetes, to enhance our understanding of the pathogenesis of AIDs and offer valuable references for the diagnosis and treatment of AIDs.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

Clinical analysis of neuromyelitis optica spectrum disease with area postrema syndrome as the initial symptom

OBJECTIVE

The objective of this study was to report and discuss clinical analysis, including the diagnosis and treatment of 4 cases of neuromyelitis optica spectrum disease (NMOSD) with area postrema syndrome (APS) as the first symptom.

METHODS

Four patients with intractable nausea, vomiting, and confirmed NMOSD were included in the final analysis. All of these patients were initially misdiagnosed and mismanaged.

RESULTS

Among the 4 patients, 3 were admitted to the department of gastroenterology at the onset of the disease, and 2 were not correctly diagnosed and treated promptly due to misdiagnosis. Therefore, their symptoms worsened, and they were transferred to Intensive Care Unit (ICU) for life support. No obvious early medulla lesions were found in one patient. One patient was treated with intravenous immunoglobulin, methylprednisolone, and plasma exchange, but there was no significant clinical improvement, after which the disease relapsed during the treatment with low-dose rituximab.

CONCLUSION

The clinical manifestations of NMOSD are complex and diverse, and the initial symptoms, onset age of the patient, and magnetic resonance imaging (MRI) findings can influence the final diagnosis. Early identification of the APS and timely therapy can prevent visual and physical disabilities, even respiratory failure, coma, and cardiac arrest. Therefore, it is necessary to identify specific and sensitive serum and imaging markers for predicting the prognosis and recurrence of the disease.

Relapses shortly after rituximab treatment in neuromyelitis optica spectrum disorder

OBJECTIVE

Rituximab (RTX), an anti-CD20 monoclonal antibody, has been demonstrated to be a useful maintenance therapy for neuromyelitis optica spectrum disorder (NMOSD). However, few patients may suffer from relapses shortly after RTX. In order to investigate the clinical features of RTX-related relapses and guide therapeutic strategy, 3 patients in our department were reported and literatures were reviewed.

METHODS

We reported three NMOSD patients suffered from relapses shortly after rituximab treatment in our hospital and reviewed 13 patients reported in literatures. Their demographic characteristics, clinical features and therapeutic strategy were retrospectively analyzed.

RESULTS

Sixteen patients, including three cases reported in this study, experienced 21 attacks within 1 month after RTX infusion. All of them were women with an age at onset of 34.0 ± 15.0 years. Fourteen patients were seropositive for aquaporin-4 antibody, and one was seropositive for myelin oligodendrocyte glycoprotein antibody. 57.1% (12/21) of RTX-related relapses occurred after the first use of RTX. Their clinical manifestations included optic neuritis (8/21), myelitis (11/21), and the other two relapses without detailed descriptions. Also, 62.5% (10/16) of patients had a history of prior relapses within 3 months before RTX infusions, and the location of nine relapses overlapped with previous relapses. RTX was given again after the first RTX-related relapse in eight patients, three of them with low-dosage RTX stayed stable for years, and five patients with full-dosage RTX experienced another RTX-related relapse.

CONCLUSIONS

Relapses may occur shortly after RTX treatment in NMOSD. RTX-related relapse did not necessarily mean that RTX was ineffective in low-dosage regimen. Timely and sufficient treatment of RTX is crucial to prevent a relapse. It may be more reasonable to monitor B cell repopulation so as to determine a re-treatment regimen. RTX-related relapse following full-dosage RTX may be a predictor for a second time RTX-related relapse and it may be reasonable to switch to other immunosuppressants in early stage.

Immune repertoire: Revealing the "real-time" adaptive immune response in autoimmune diseases

The diversity of the immune repertoire (IR) enables the human immune system to distinguish multifarious antigens (Ags) that humans may encounter throughout life. At the same time, bias or abnormalities in the IR also pay a contribution to the pathogenesis of autoimmune diseases. Rapid advancements in high-throughput sequencing (HTS) technology have ushered in a new era of immune studies, revealing novel molecules and pathways that might result in autoimmunity. In the field of IR, HTS can monitor the immune response status and identify disease-specific immune repertoires. In this review, we summarize updated progress on the mechanisms of the IR and current related studies on four autoimmune diseases, particularly focusing on systemic lupus erythematosus (SLE). These autoimmune diseases can exhibit slightly or significantly skewed IRs and provide novel insights that inform our comprehending of disease pathogenesis and provide potential targets for diagnosis and treatment.

Single-cell repertoire tracing identifies rituximab-resistant B cells during myasthenia gravis relapses

Rituximab, a B cell-depleting therapy, is indicated for treating a growing number of autoantibody-mediated autoimmune disorders. However, relapses can occur after treatment, and autoantibody-producing B cell subsets may be found during relapses. It is not understood whether these autoantibody-producing B cell subsets emerge from the failed depletion of preexisting B cells or are generated de novo. To further define the mechanisms that cause postrituximab relapse, we studied patients with autoantibody-mediated muscle-specific kinase (MuSK) myasthenia gravis (MG) who relapsed after treatment. We carried out single-cell transcriptional and B cell receptor profiling on longitudinal B cell samples. We identified clones present before therapy that persisted during relapse. Persistent B cell clones included both antibody-secreting cells and memory B cells characterized by gene expression signatures associated with B cell survival. A subset of persistent antibody-secreting cells and memory B cells were specific for the MuSK autoantigen. These results demonstrate that rituximab is not fully effective at eliminating autoantibody-producing B cells and provide a mechanistic understanding of postrituximab relapse in MuSK MG.

Anti-CD20 Monoclonal Antibodies for Relapsing and Progressive Multiple Sclerosis

Multiple sclerosis (MS) was previously thought to be a T-cell-mediated, demyelinating disease of the central nervous system. Disease-modifying therapies targeting T cells have, indeed, shown remarkable efficacy in patients with relapsing-remitting MS. However, these therapies do also target B cells, and a B-cell-depleting monoclonal antibody (ocrelizumab) has recently been approved for MS therapy and is efficacious not only in relapsing forms of MS but also in some patients with primary progressive MS. This suggests that B cells may play a more important role in the pathogenesis of MS than previously appreciated. We review the potential roles of B cells, which are the precursors of antibody-secreting plasma cells in the pathogenesis of MS. Furthermore, we provide an overview of the characteristics and clinical data for the four monoclonal antibodies (ocrelizumab, ofatumumab, rituximab, and ublituximab) that have been approved, are currently been used off-label or are being investigated as treatments for MS. These antibodies all target the cluster of differentiation (CD)-20 molecule and bind to distinct or overlapping epitopes on B cells and a subset of T cells that express CD20. This leads to B-cell depletion and, possibly, to depletion of CD20-positive T cells. The net result is strong suppression of clinical and radiological disease activity as well as slowing of the development of persisting neurological impairment.

Effectiveness and tolerability of immunosuppressants and monoclonal antibodies in preventive treatment of neuromyelitis optica spectrum disorders: A systematic review and network meta-analysis

BACKGROUND

Several immunosuppressants or monoclonal antibodies have been used as preventive treatment for neuromyelitis optica spectrum disorders (NMOSD); however, the optimal therapies have not been clarified. In this study, we aimed to compare and rank the effectiveness and tolerability of all preventive therapies for NMOSD.

METHODS

Qualified studies were identified in a search of MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases. We combined direct and indirect evidence via meta-analyses. The annualized relapse rate (ARR) was defined as the primary outcome. Secondary outcomes included the Expanded Disability Status Scale (EDSS) score and hazard ratios (HR) for the counts of adverse events (AEs).

RESULTS

We identified one randomized controlled trial (RCT) and five observational studies including a total 631 patients with NMOSD. Among these, the follow-up time ranged from 12 to 40 months. For the primary outcome, rituximab (RTX) was hierarchically superior, with the significant standardized mean difference versus azathioprine (-0.86; 95% confidence interval: -1.60, -0.11). Mycophenolate mofetil (MMF) was ranked the most tolerable therapy, whereas cyclophosphamide was the least tolerable.

CONCLUSION

RTX and MMF may be recommended as optimal treatments to prevent relapse in NMOSD. Low-dose cyclosporine A could be a promising alternative therapy.

B-cell depletion induces a shift in self antigen specific B-cell repertoire and cytokine pattern in patients with bullous pemphigoid

Bullous Pemphigoid is the most common auto-immune bullous skin disease. It is characterized by the production of auto-antibodies directed against 2 proteins of the hemi-desmosome (BP180 and BP230). We assessed the efficacy and mechanisms of action of rituximab, an anti-CD20 monoclonal antibody, in 17 patients with severe and relapsing type of bullous pemphigoid. The phenotype, cytokine gene expression, and rearrangement of BP180-specific B-cell receptor genes were performed over 2 years following treatment. At the end of the study, 5 patients had died, 3 had withdrawn from the study, and 9 patients were in complete remission. The one- and two-year relapse rates were 44.1% (95% Confidence Interval (CI): 21.0-76.0%) and 66.5%, (95% CI: 38.4-91.4%), respectively. Phenotypic analyses confirmed dramatic B-cell depletion, which lasted for 9 to 12 months. The ELISA values of serum anti-BP180 antibodies and the frequency of BP180-specific circulating B cells decreased dramatically following treatment, which paralleled the improvement of skin lesions. During B-cell reconstitution, a polyclonal IgM repertoire appeared and a shift in the rearrangement of the B-cell receptor genes of BP180-specific circulating B cells was observed. Concurrently, we observed a decrease of IL-15, IL-6 and TNFα expressing BP180-specific B cells, and the emergence of IL-10 and IL-1RA-expressing BP180-specific IgM+ B cells in patients in complete remission off therapy, suggesting the functional plasticity of BP180-specific auto-immune B cells after rituximab treatment.

Functional characterization of reappearing B cells after anti-CD20 treatment of CNS autoimmune disease

B cell depletion via anti-CD20 monoclonal antibodies is a novel, highly efficient therapy for multiple sclerosis (MS). In a murine MS model, we investigated three mechanistic questions that cannot be addressed in humans. First, we established that a fraction of mature B cells in the spleen is resistant to anti-CD20. Second, we determined that, after cessation of treatment, splenic and bone-marrow B cells reconstitute in parallel, substantially preceding B cell reappearance in blood. Third, we observed that, in a model involving activated B cells, the post–anti-CD20 B cell pool contained an elevated frequency of differentiated, myelin-reactive B cells. Together, our findings reveal mechanisms by which pathogenic B cells may persist in anti-CD20 treatment.

The anti-CD20 antibody ocrelizumab, approved for treatment of multiple sclerosis, leads to rapid elimination of B cells from the blood. The extent of B cell depletion and kinetics of their recovery in different immune compartments is largely unknown. Here, we studied how anti-CD20 treatment influences B cells in bone marrow, blood, lymph nodes, and spleen in models of experimental autoimmune encephalomyelitis (EAE). Anti-CD20 reduced mature B cells in all compartments examined, although a subpopulation of antigen-experienced B cells persisted in splenic follicles. Upon treatment cessation, CD20⁺ B cells simultaneously repopulated in bone marrow and spleen before their reappearance in blood. In EAE induced by native myelin oligodendrocyte glycoprotein (MOG), a model in which B cells are activated, B cell recovery was characterized by expansion of mature, differentiated cells containing a high frequency of myelin-reactive B cells with restricted B cell receptor gene diversity. Those B cells served as efficient antigen-presenting cells (APCs) for activation of myelin-specific T cells. In MOG peptide-induced EAE, a purely T cell-mediated model that does not require B cells, in contrast, reconstituting B cells exhibited a naive phenotype without efficient APC capacity. Our results demonstrate that distinct subpopulations of B cells differ in their sensitivity to anti-CD20 treatment and suggest that differentiated B cells persisting in secondary lymphoid organs contribute to the recovering B cell pool.

Antibody repertoire analysis in polygenic autoimmune diseases

High-throughput sequencing of the DNA/RNA encoding antibody heavy- and light-chains is rapidly transforming the field of adaptive immunity. It can address key questions, including: (i) how the B-cell repertoire differs in health and disease; and (ii) if it does differ, the point(s) in B-cell development at which this occurs. The advent of technologies, such as whole-genome sequencing, offers the chance to link abnormalities in the B-cell antibody repertoire to specific genomic variants and polymorphisms. Here, we discuss the current research using B-cell antibody repertoire sequencing in three polygenic autoimmune diseases where there is good evidence for a pathological role for B-cells, namely systemic lupus erythematosus, multiple sclerosis and rheumatoid arthritis. These autoimmune diseases exhibit significantly skewed B-cell receptor repertoires compared with healthy controls. Interestingly, some common repertoire defects are shared between diseases, such as elevated IGHV4-34 gene usage. B-cell clones have effectively been characterized and tracked between different tissues and blood in autoimmune disease. It has been hypothesized that these differences may signify differences in B-cell tolerance; however, the mechanisms and implications of these defects are not clear.

Role of Immunological Memory Cells as a Therapeutic Target in Multiple Sclerosis

Pharmacological targeting of memory cells is an attractive treatment strategy in various autoimmune diseases, such as psoriasis and rheumatoid arthritis. Multiple sclerosis is the most common inflammatory disorder of the central nervous system, characterized by focal immune cell infiltration, activation of microglia and astrocytes, along with progressive damage to myelin sheaths, axons, and neurons. The current review begins with the identification of memory cell types in the previous literature and a recent description of the modulation of these cell types in T, B, and resident memory cells in the presence of different clinically approved multiple sclerosis drugs. Overall, this review paper tries to determine the potential of memory cells to act as a target for the current or newly-developed drugs.

Monitoring CD27+ memory B-cells in neuromyelitis optica spectrum disorders patients treated with rituximab: Results from a bicentric study

BACKGROUND

Rituximab (RTX) is increasingly used in the treatment of neuromyelitis optica spectrum disorder (NMO-SD). Administration regimen is not consensual as there is no reliable biomarker of RTX efficacy. In most cases, after induction, RTX is administered systematically every 6months.

OBJECTIVE

To assess efficacy and safety of a maintenance regimen based on CD19+ CD27+ memory B-cell (mBc) detection.

METHODS

We conducted a study in two French centers, including patients with NMO-SD who received an induction therapy with RTX. We compared the number of administered infusions, relapses and EDSS depending on two maintenance schemes (S1: administration of 1g RTX infusion every 6months or S2: a scheme based on regular mBc detection. 1g RTX was administered if mBc was >0.05%) RESULTS: 40 patients were included (mean age: 40.2years, F/M sex ratio: 5/1). Aquaporin-4 antibodies were positive in 75% patients. Under S1 regimen, all patients received 2 infusions per year, whereas under S2, they received 1.62 infusion per year. The mean interval between infusions under S2 was 7.4months, without decrease of clinical efficacy.

CONCLUSION

In our study, mBc-based administration of RTX allowed personalizing treatment administration and in several cases to lower the cumulative dose without loss of efficacy.

Treatment of neuromyelitis optica and neuromyelitis optica spectrum disorders with rituximab using a maintenance treatment regimen and close CD19 B cell monitoring. A six-year follow-up

Neuromyelitis optinca (NMO) represents a serious demyelinating disease of the central nervous system selectively attacking the spinal cord and optic nerve. Early differential diagnosis from multiple sclerosis is of vital importance, as NMO mandates immunosuppressive and not immunomodulatory treatment. Rituximab has been recently introduced as a treatment option for NMO. However, optimal surrogate measures and treatment intervals are still unclear. Five patients (females, mean age 54±10.21years) with NMO and NMO spectrum disorders (NMOSD) were evaluated with respect to disability and relapse rate. All patients were found positive for NMO IgG. All patients (three with NMO and two with NMOSD, 1 patient with recurrent optic neuritis and 1 patient with recurrent myelitis) had received rituximab treatment for six years. One patient with NMOSD received cyclophosphamide prior to rituximab while two were misdiagnosed as multiple sclerosis and had received interferon treatment. All received rituximab infusion of 375mg/m² once per week for 4weeks and then every two months for the first two years and then every six months. B-cell counts were measured every two months and were kept in almost undetectable levels. No relapse was noted during the treatment period while EDSS score was improved in all patients. No severe adverse effects occurred during RTX treatment. Rituximab treatment on NMO and NMOSD patients showed significant improvement in disability and relapse-rate without any significant adverse effects.

Unraveling the Role of Allo-Antibodies and Transplant Injury

Alloimmunity driving rejection in the context of solid organ transplantation can be grossly divided into mechanisms predominantly driven by either T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR), though the co-existence of both types of rejections can be seen in a variable number of sampled grafts. Acute TCMR can generally be well controlled by the establishment of effective immunosuppression (1, 2). Acute ABMR is a low frequency finding in the current era of blood group and HLA donor/recipient matching and the avoidance of engraftment in the context of high-titer, preformed donor-specific antibodies. However, chronic ABMR remains a major complication resulting in the untimely loss of transplanted organs (3-10). The close relationship between donor-specific antibodies and ABMR has been revealed by the highly sensitive detection of human leukocyte antigen (HLA) antibodies (7, 11-15). Injury to transplanted organs by activation of humoral immune reaction in the context of HLA identical transplants and the absence of donor specific antibodies (17-24), strongly suggest the participation of non-HLA (nHLA) antibodies in ABMR (25). In this review, we discuss the genesis of ABMR in the context of HLA and nHLA antibodies and summarize strategies for ABMR management.