Refractory Primary Sjögren Syndrome Successfully Treated With Bortezomib:

Emerging biologic frontiers for Sjogren's syndrome: Unveiling novel approaches with emphasis on extra glandular pathology

Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by exocrine gland dysfunction, leading to dry eyes and mouth. Despite growing interest in biologic therapies for pSS, FDA approval has proven challenging due to trial complications. This review addresses the absence of a molecular-target-based approach to biologic therapy development and highlights novel research on drug targets and clinical trials. A literature search identified potential pSS treatment targets and recent advances in molecular understanding. Overlooking extraglandular symptoms like fatigue and depression is a notable gap in trials. Emerging biologic agents targeting cytokines, signal pathways, and immune responses have proven efficacy. These novel therapies could complement existing methods for symptom alleviation. Improved grading systems accounting for extraglandular symptoms are needed. The future of pSS treatment may involve gene, stem-cell, and tissue-engineering therapies. This narrative review offers insights into advancing pSS management through innovative biologic interventions.

Potential mechanisms and drug prediction of Rheumatoid Arthritis and primary Sjögren's Syndrome: A public databases-based study

Rheumatoid arthritis (RA) and primary Sjögren's syndrome (pSS) are the most common systemic autoimmune diseases, and they are increasingly being recognized as occurring in the same patient population. These two diseases share several clinical features and laboratory parameters, but the exact mechanism of their co-pathogenesis remains unclear. The intention of this study was to investigate the common molecular mechanisms involved in RA and pSS using integrated bioinformatic analysis. RNA-seq data for RA and pSS were picked up from the Gene Expression Omnibus (GEO) database. Co-expression genes linked with RA and pSS were recognized using weighted gene co-expression network analysis (WGCNA) and differentially expressed gene (DEG) analysis. Then, we screened two public disease-gene interaction databases (GeneCards and Comparative Toxicogenomics Database) for common targets associated with RA and pSS. The DGIdb database was used to predict therapeutic drugs for RA and pSS. The Human microRNA Disease Database (HMDD) was used to screen out the common microRNAs associated with RA and pSS. Finally, a common miRNA-gene network was created using Cytoscape. Four hub genes (CXCL10, GZMA, ITGA4, and PSMB9) were obtained from the intersection of common genes from WGCNA, differential gene analysis and public databases. Twenty-four drugs corresponding to hub gene targets were predicted in the DGIdb database. Among the 24 drugs, five drugs had already been reported for the treatment of RA and pSS. Other drugs, such as bortezomib, carfilzomib, oprozomib, cyclosporine and zidovudine, may be ideal drugs for the future treatment of RA patients with pSS. According to the miRNA-gene network, hsa-mir-21 may play a significant role in the mechanisms shared by RA and pSS. In conclusion, we identified commom targets as potential biomarkers in RA and pSS from publicly available databases and predicted potential drugs based on the targets. A new understanding of the molecular mechanisms associated with RA and pSS is provided according to the miRNA-gene network.

Targeting plasma cells in systemic autoimmune rheumatic diseases - Promises and pitfalls

Plasma cells are the antibody secretors of the immune system. Continuous antibody secretion over years can provide long-term immune protection but could also be held responsible for long-lasting autoimmunity in case of self-reactive plasma cells. Systemic autoimmune rheumatic diseases (ARD) affect multiple organ systems and are associated with a plethora of different autoantibodies. Two prototypic systemic ARDs are systemic lupus erythematosus (SLE) and Sjögren's disease (SjD). Both diseases are characterized by B-cell hyperactivity and the production of autoantibodies against nuclear antigens. Analogues to other immune cells, different subsets of plasma cells have been described. Plasma cell subsets are often defined dependent on their current state of maturation, that also depend on the precursor B-cell subset from which they derived. But, a universal definition of plasma cell subsets is not available so far. Furthermore, the ability for long-term survival and effector functions may differ, potentially in a disease-specific manner. Characterization of plasma cell subsets and their specificity in individual patients can help to choose a suitable targeting approach for either a broad or more selective plasma cell depletion. Targeting plasma cells in systemic ARDs is currently challenging because of side effects or varying depletion efficacies in the tissue. Recent developments, however, like antigen-specific targeting and CAR-T-cell therapy might open up major benefits for patients beyond current treatment options.

Pathogenesis and treatment of Sjogren's syndrome: Review and update

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar to that of SLE, RA, and MS, biotherapeutic strategies of SS consist of neutralizing antibodies and inflammation-related receptor blockers targeting proinflammatory signaling pathways. However, clinical research on SS therapy is comparatively rare. Moreover, the differences in the curative effects of immunotherapies among SS and other autoimmune diseases are not fully understood. We emphasize that targeted drugs, low-side-effect drugs, and combination therapies should be the focus of future research.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.

Bortezomib in autoimmune hemolytic anemia and beyond

Bortezomib is a first-in-class, potent, selective and reversible proteasome inhibitor approved for the treatment of multiple myeloma (MM) and relapsed/refractory mantle cell lymphoma. In these diseases, bortezomib targets plasma cells and lymphocytes reducing tumor burden. Recently, preclinical evidence highlighted its efficacy in reducing long-lived plasma cells responsible of autoantibodies production in several models of autoimmune conditions. These findings paved the way to a number of experiences of bortezomib use in patients with various autoimmune conditions, including autoimmune hemolytic anemia (AIHA). The latter is a nice model of autoimmunity in hematology and is caused by the production of autoantibodies against erythrocytes resulting in various degrees of hemolytic anemia. AIHA is classified in warm and cold forms according to the thermal characteristics of the autoantibody, and first-line treatment mainly relies on steroids for warm cases and the anti-CD20 rituximab for cold ones. Relapsed/refractory cases are still an unmet need, and bortezomib has been proposed in this setting with intriguing efficacy. In this review, we collected available literature on bortezomib use in AIHA and in other immune-mediated hematologic and non-hematologic diseases. Overall, most experiences highlight bortezomib efficacy even in multi-relapsed/refractory patients and suggest to consider its use in AIHA after rituximab failure.

Towards Drug Repurposing in Cancer Cachexia: Potential Targets and Candidates

As a multifactorial and multiorgan syndrome, cancer cachexia is associated with decreased tolerance to antitumor treatments and increased morbidity and mortality rates. The current approaches for the treatment of this syndrome are not always effective and well established. Drug repurposing or repositioning consists of the investigation of pharmacological components that are already available or in clinical trials for certain diseases and explores if they can be used for new indications. Its advantages comparing to de novo drugs development are the reduced amount of time spent and costs. In this paper, we selected drugs already available or in clinical trials for non-cachexia indications and that are related to the pathways and molecular components involved in the different phenotypes of cancer cachexia syndrome. Thus, we introduce known drugs as possible candidates for drug repurposing in the treatment of cancer-induced cachexia.

Trajectory mapping of primary Sjögren's syndrome via transcriptome learning demonstrates limitations of peripheral blood sequencing

Primary Sjögren's syndrome (pSS) is a complex autoimmune disease characterized by aberrant immune cell action against secretory glands throughout the body. A number of studies have previously identified unique characteristics in the circulating expression profile of white blood cells of pSS patients. However, the molecular progression pattern of pSS is unclear. Through a systematic analysis of pSS transcriptome information, we found that pSS transcriptomes display broad heterogeneity, but cannot be distinguished from the broad range of possible profiles of healthy controls. Instead, only sample learning using a subset of pre-identified signature genes could achieve partial separation through a trajectory governed by interferon activity. Interestingly, this trajectory is correlated with a decrease in dendritic cell counts. Our study thus highlights a major limitation to the utility of broad blood transcriptome analysis in the context of pSS, while also identifying several factors that influence the divergence between patient samples.

Targeting B cells in the pre-phase of systemic autoimmunity globally interferes with autoimmune pathology

Systemic lupus erythematosus (SLE) is characterized by a loss of self-tolerance, systemic inflammation, and multi-organ damage. While a variety of therapeutic interventions are available, it has become clear that an early diagnosis and treatment may be key to achieve long lasting therapeutic responses and to limit irreversible organ damage. Loss of humoral tolerance including the appearance of self-reactive antibodies can be detected years before the actual onset of the clinical autoimmune disease, representing a potential early point of intervention. Not much is known, however, about how and to what extent this pre-phase of disease impacts the onset and development of subsequent autoimmunity. By targeting the B cell compartment in the pre-disease phase of a spontaneous mouse model of SLE we now show, that resetting the humoral immune system during the clinically unapparent phase of the disease globally alters immune homeostasis delaying the downstream development of systemic autoimmunity.

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The clinically unapparent pre-phase of SLE impacts clinical disease

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Autoreactive IgM antibodies represent a biomarker for early therapeutic intervention

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Pre-phase B cells orchestrate clinical disease

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Depleting pre-phase B cells diminishes disease pathology

The Multiple Roles of B Cells in the Pathogenesis of Sjögren's Syndrome

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disease characterized by lymphocytic infiltration and tissue destruction of exocrine glands such as salivary glands. Although the formation of ectopic lymphoid tissue in exocrine glands and overproduction of autoantibodies by autoreactive B cells highlight the critical involvement of B cells in disease development, the precise roles of various B cell subsets in pSS pathogenesis remain partially understood. Current studies have identified several novel B cell subsets with multiple functions in pSS, among which autoreactive age-associated B cells, and plasma cells with augmented autoantibody production contribute to the disease progression. In addition, tissue-resident Fc Receptor-Like 4 (FcRL4)⁺ B cell subset with enhanced pro-inflammatory cytokine production serves as a key driver in pSS patients with mucosa-associated lymphoid tissue (MALT)-lymphomas. Recently, regulatory B (Breg) cells with impaired immunosuppressive functions are found negatively correlated with T follicular helper (Tfh) cells in pSS patients. Further studies have revealed a pivotal role of Breg cells in constraining Tfh response in autoimmune pathogenesis. This review provides an overview of recent advances in the identification of pathogenic B cell subsets and Breg cells, as well as new development of B-cell targeted therapies in pSS patients.

Role of Proteasomes in Inflammation

The ubiquitin–proteasome system (UPS) is involved in multiple cellular functions including the regulation of protein homeostasis, major histocompatibility (MHC) class I antigen processing, cell cycle proliferation and signaling. In humans, proteasome loss-of-function mutations result in autoinflammation dominated by a prominent type I interferon (IFN) gene signature. These genomic alterations typically cause the development of proteasome-associated autoinflammatory syndromes (PRAAS) by impairing proteasome activity and perturbing protein homeostasis. However, an abnormal increased proteasomal activity can also be found in other human inflammatory diseases. In this review, we cast a light on the different clinical aspects of proteasomal activity in human disease and summarize the currently studied therapeutic approaches.

Skin-Associated B Cells in the Pathogenesis of Cutaneous Autoimmune Diseases-Implications for Therapeutic Approaches

B lymphocytes are crucial mediators of systemic immune responses and are known to be substantial in the pathogenesis of autoimmune diseases with cutaneous manifestations. Amongst them are lupus erythematosus, dermatomyositis, systemic sclerosis and psoriasis, and particularly those driven by autoantibodies such as pemphigus and pemphigoid. However, the concept of autoreactive skin-associated B cells, which may reside in the skin and locally contribute to chronic inflammation, is gradually evolving. These cells are believed to differ from B cells of primary and secondary lymphoid organs and may provide additional features besides autoantibody production, including cytokine expression and crosstalk to autoreactive T cells in an antigen-presenting manner. In chronically inflamed skin, B cells may appear in tertiary lymphoid structures. Those abnormal lymph node-like structures comprise a network of immune and stromal cells possibly enriched by vascular structures and thus constitute an ideal niche for local autoimmune responses. In this review, we describe current considerations of different B cell subsets and their assumed role in skin autoimmunity. Moreover, we discuss traditional and B cell-associated approaches for the treatment of autoimmune skin diseases, including drugs targeting B cells (e.g., CD19- and CD20-antibodies), plasma cells (e.g., proteasome inhibitors, CXCR4 antagonists), activated pathways (such as BTK- and PI3K-inhibitors) and associated activator molecules (BLyS, APRIL).

Biologic therapy in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disease with complex and diverse clinical manifestations. It is characterized by lymphocyte infiltration of exocrine glands such as the salivary gland and lacrimal gland leading to insufficient secretion of the gland, manifested as dry mouth and dry eyes. In addition, it can involve extraglandular organs and cause systemic damage. The pathogenesis of SS is still unclear. At present, symptomatic treatment is the mainstay and there is a lack of effective therapy. With the development of molecular pathways underlying the pathogenesis of SS, more and more novel biological agents are used to treat SS. We summarized and analyzed the existing evidences on the efficacy of biological treatment of SS and their targets. Analysis of the efficacy of biological therapy and improvement of treatment strategies can help to give full play to its therapeutic advantages.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

Generate-Boost: study protocol for a prospective, multicenter, randomized controlled, double-blinded phase II trial to evaluate efficacy and safety of bortezomib in patients with severe autoimmune encephalitis

BACKGROUND

Autoimmune encephalitis is a new spectrum of autoimmune disorders of the central nervous system (CNS), which are characterized by pathogenic autoantibodies against neuronal surface antigens. Clinical presentations range from acute to subacute encephalopathy with neurological and psychiatric symptoms, and life-threatening autonomic dysfunction in severe cases. There exist no approved therapies nor is data available from controlled clinical trials. Patients are usually treated with diverse combinations of immunotherapy. However, effect of immunotherapy on antibody-producing cells and thus on levels of pathogenic autoantibodies is insufficient. Therefore, therapeutic response is sometimes prolonged with necessity of long-time intensive care treatment and also irreversible deficits occur in severe cases. This trial will investigate the efficacy and safety of bortezomib, a proteasome inhibitor known to selectively deplete plasma cells, in patients with severe autoimmune encephalitis who have been treated with rituximab with insufficient response.

METHODS

Generate-Boost is an investigator-initiated, multicenter, double-blinded, randomized controlled phase II trial which will be conducted in specialized neurological hospitals within the GENERATE (GErman NEtwork for Research on AuToimmune Encephalitis) network in Germany. Adult patients with severe autoimmune encephalitis (modified Rankin scale, mRS ≥ 3), autoantibodies against neuronal surface antigens, and pretreatment with rituximab are eligible for study participation. Fifty patients will be randomized 1:1 and undergo up to 3 cycles (each 21 days with 4 s. c. applications) of bortezomib or placebo. All patients will receive concomitant medication with dexamethasone, acyclovir and co-trimoxazole. The primary efficacy endpoint is the mRS score 17 weeks after first treatment application. Secondary endpoints are neurocognitive function, antibody titers, markers of neuronal cell damage, length of ICU/hospital stay, and mRS and Glasgow coma scale scores throughout the trial up to week 17. General and bortezomib-specific adverse events are monitored continuously.

DISCUSSION

The expected outcome of the study is to obtain first reliable data on a hypothesis-driven therapeutic option in severe and difficult-to-treat autoimmune encephalitis. If treatment with bortezomib is beneficial in these cases, this will be the basis for implementation in the current guidelines.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT03993262 . Registered June 20, 2019; German Clinical Trials Register, DRKS00017497.

Bortezomib at therapeutic doses poorly passes the blood-brain barrier and does not impair cognition

The 26S proteasome inhibitor bortezomib is currently used to treat multiple myeloma but also is effective in the treatment of antibody-mediated autoimmune disorders. One clinical concern is bortezomib's toxicity towards the (central) nervous system. We used standardized neuropsychological testing to assess cognitive function in six patients with myasthenia gravis and systemic lupus erythematodes before and after treatment with a mean cumulative dose of 9.4 mg m^-2 bortezomib. In addition, cognitive performance was measured in adult C57Bl/6 mice after treatment with a human equivalent cumulative dose of 15.6 mg m^-2. Bortezomib concentrations were analysed in the human CSF as well as the brain tissue and serum of adult C57Bl/6 mice at various time points after the injection of 1.3 mg m^-2 bortezomib with liquid chromatography-tandem mass spectrometry. Neither patients nor mice showed signs of cognitive impairment after bortezomib therapy. Bortezomib concentrations in the human CSF and murine brain tissue reached only 5-7% of serum concentrations with comparable concentrations measured in the hippocampus and the neocortex. Five-fold higher concentrations were needed to damage neuronal cells in vitro. In conclusion, penetration of the intact blood-brain barrier by bortezomib is low. Overall, our data show that bortezomib is a safe medication in terms of central nervous system toxicity.

Is There a Future for Anti-CD38 Antibody Therapy in Systemic Autoimmune Diseases?

CD38 is a type II glycoprotein highly expressed on plasmablasts, short-lived and long-lived plasma cells, but weakly expressed on other lymphoid cells, myeloid cells and non-hematopoietic cells. This expression pattern makes CD38 an interesting target for a targeted therapy aiming to deplete antibody-producing plasma cells. We present data suggesting that anti-CD38 therapy may be effective for the prevention at the preclinical stage and for the treatment of established autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, Sjögren’s syndrome and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Given the high unmet need for efficacious disease-modifying treatment in these diseases, studies are warranted to determine if anti-CD38 antibody-based therapies may delay or prevent the disease progression of systemic autoimmune diseases.

Pathogenic memory plasma cells in autoimmunity

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Memory plasma cells are long-lived but require specialized niches for their survival.

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Memory plasma cells are refractory to conventional immunosuppression.

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Pathogenic memory plasma cells represent ‘roadblocks’ to response to conventional therapy.

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Strategies for (selective) targeting of memory plasma cells are in preclinical and clinical tests.

Berunda Polypeptides: Biheaded Rapamycin Carriers for Subcutaneous Treatment of Autoimmune Dry Eye Disease

The USFDA-approved immunosuppressive drug rapamycin (Rapa), despite its potency, is limited by poor bioavailability and a narrow therapeutic index. In this study, we sought to improve bioavailability of Rapa with subcutaneous (SC) administration and to test its therapeutic feasibility and practicality in a murine model of Sjögren's syndrome (SS), a systemic autoimmune disease with no approved therapies. To improve its therapeutic index, we formulated Rapa with a carrier termed FAF, a fusion of the human cytosolic FK506-binding protein 12 (FKBP12) and an elastin-like polypeptide (ELP). The resulting 97 kDa FAF (i) has minimal burst release, (ii) is "humanized", (iii) is biodegradable, (iv) solubilizes two Rapa per FAF, and (v) avoids organic solvents or amphiphilic carriers. Demonstrating high stability, FAF remained soluble and monodisperse with a hydrodynamic radius of 8 nm at physiological temperature. A complete pharmacokinetic (PK) analysis of FAF revealed that the bioavailability of SC FAF was 60%, with significantly higher blood concentration during the elimination phase compared to IV FAF. The plasma concentration of Rapa delivered by FAF was 8-fold higher with a significantly increased plasma-to-whole blood ratio relative to free Rapa, 24 h after injection. To evaluate therapeutic effects, FAF-Rapa was administered SC every other day for 2 weeks to male non-obese diabetic (NOD) mice, which develop an SS-like autoimmune-mediated lacrimal gland (LG) inflammation and other characteristic features of SS. Both FAF-Rapa and free Rapa exhibited immunomodulatory effects by significantly suppressing lymphocytic infiltration, gene expression of IFN-γ, MHC II, type I collagen and IL-12a, and cathepsin S (CTSS) activity in LG compared to controls. Serum chemistry and histopathological analyses in major organs revealed no apparent toxicity of FAF-Rapa. Given its improved PK and equipotent therapeutic efficacy compared to free Rapa, FAF-Rapa is of further interest for systemic treatments for autoimmune diseases like SS.

Managing fatigue in patients with primary Sjögren's syndrome: challenges and solutions

Primary Sjögren's syndrome (pSS) patients identify fatigue as their most important symptom and the one most difficult to cope with, but there are still many challenges and few solutions to manage this debilitating symptom. Promising pharmacological treatments, such as rituximab, have failed in more stringent tests including randomized controlled trials (RCTs) and meta-analysis. While non-pharmacological interventions may be safer, less costly, and address other common comorbidities, to date only aerobic exercise seems to be effective at reducing fatigue in pSS. All interventions, pharmacological or not, need to be tested in high-quality RCTs. The aim of this review is to provide an overview of fatigue management in pSS and discuss potential opportunities for future research.

B cells in Sjögren's syndrome: from pathophysiology to therapeutic target

Biological abnormalities associated with B lymphocytes are a hallmark of patients with primary Sjögren's syndrome. Those patients present abnormal distribution of B lymphocytes in peripheral blood and B cells in exocrine glands. B cells produce auto-antibodies, cytokines and present antigens but can also suppressive functions. In this review, we will summarize current knowledge on B cells in primary Sjögren's syndrome patients, demonstrate their critical role in the immunopathology of the disease and describe the past and current trials targeting B cells.

Required Immunoproteasome Subunit Inhibition Profile for Anti-Inflammatory Efficacy and Clinical Candidate KZR-616 ((2 S,3 R)- N-(( S)-3-(Cyclopent-1-en-1-yl)-1-(( R)-2-methyloxiran-2-yl)-1-oxopropan-2-yl)-3-hydroxy-3-(4-methoxyphenyl)-2-(( S)-2-(2-morpholinoacetamido)propanamido)propenamide)

Selective immunoproteasome inhibition is a promising approach for treating autoimmune disorders, but optimal proteolytic active site subunit inhibition profiles remain unknown. We reveal here our design of peptide epoxyketone-based selective low molecular mass polypeptide-7 (LMP7) and multicatalytic endopeptidase complex subunit-1 (MECL-1) subunit inhibitors. Utilizing these and our previously disclosed low molecular mass polypeptide-2 (LMP2) inhibitor, we demonstrate a requirement of dual LMP7/LMP2 or LMP7/MECL-1 subunit inhibition profiles for potent cytokine expression inhibition and in vivo efficacy in an inflammatory disease model. These and additional findings toward optimized solubility led the design and selection of KZR-616 disclosed here and presently in clinical trials for treatment of rheumatic disease.

Relapsed/refractory acquired thrombotic thrombocytopenic purpura in a patient with Sjögren syndrome: Case report and review of the literature

RATIONALE

Thrombotic thrombocytopenic purpura (TTP) is a rare, fatal disorder which could be caused by autoimmune diseases. However, TTP secondary to Sjögren syndrome (SS) is extremely rare.

PATIENT CONCERNS

A 47-year- old woman with an 8-year history of SS was admitted due to skin ecchymosis and bleeding gums. Then she gradually developed fever and headache.

DIAGNOSES

Laboratory investigations suggested anemia, thrombocytopenia, increased lactic dehydrogenase, and a disintegrin-like metalloproteinase with thrombospondin motif type 1 member 13 (ADAMTS13) activity deficiency with high inhibitor titers. Acquired TTP was thus diagnosed.

INTERVENTIONS

Plasma exchange (PE) was the first choice for treatment, while glucocorticoid, cyclosporine A (CSA), rituximab, and intravenous immunoglobulin (IVIG) were used simultaneously. Bortezomib, a selective proteasome inhibitor and thereby inducing apoptosis in both B-cells and plasma cells, was added.

OUTCOMES

She was discharged from the hospital and then treated with prednisone of 40 mg/d and hydroxychloroquine. The patient remained in full remission.

LESSONS

We conclude that bortezomib should be considered for patients with TTP refractory to PE, steroids, and rituximab due to its efficacy and relatively favorable side effect profile.

Bortezomib treatment for severe refractory anti-NMDA receptor encephalitis

OBJECTIVE

To evaluate the therapeutic potential of bortezomib, a proteasome inhibitor that target plasma cells, in order to revive stalled recovery in patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis who remain bedridden even after aggressive immunotherapy.

METHODS

We consecutively enrolled patients with anti-NMDA receptor encephalitis who remained bedridden after first-line immunotherapy (steroids and intravenous immunoglobulin), second-line immunotherapy (rituximab), and tocilizumab treatment, and treated them with subcutaneous bortezomib. Clinical response, functional recovery, and changes in antibody titer in the serum and cerebrospinal fluid were measured.

RESULTS

Before the bortezomib treatment, the five patients with severe refractory anti-NMDA receptor encephalitis were in a vegetative state. During the 8 months of follow-up period, three patients improved to minimally conscious states within 2 months of bortezomib treatment, one failed to improve from a vegetative state. However, no patient achieved functional recovery as measured by the modified Rankin Scale score (mRS). Three patients advanced to a cyclophosphamide with bortezomib and dexamethasone regimen, which only resulted in additional adverse events, without mRS improvement. Among the four patients whose antibody titer was followed, two demonstrated a twofold decrease in the antibody titer in serum and/or cerebrospinal fluid after 2 cycles of bortezomib.

INTERPRETATION

Although there were some improvements in severe refractory patients, clinical response to bortezomib was limited and not clearly distinguishable from the natural course of the disease. The clinical benefit of bortezomib in recent studies requires further validation in different clinical settings.

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.

Proteasome inhibition suppresses Th17 cell generation and ameliorates autoimmune development in experimental Sjögren's syndrome

Immunoproteasome activation in immune cells is involved in the modulation of immune responses. Increasing evidence indicates that proteasome inhibitors show beneficial effects in treating autoimmune diseases, but it remains unclear whether proteasome inhibition is an effective approach for suppressing autoimmune development in Sjögren's syndrome (SS). Our previous work has demonstrated a critical role for Th17 cells in the development of experimental SS (ESS) in mice. In this study, we detected high levels of low-molecular-weight protein 7 (LMP7), a key subunit of the immunoproteasome, in Th17 cells from ESS mice. Moreover, treatment with bortezomib (BTZ), a proteasome inhibitor, markedly suppressed Th17 differentiation in both murine and human naive T cells in culture. Furthermore, ESS mice treated with BTZ displayed significantly higher saliva flow rates and a reduction in tissue destruction in the salivary glands compared with vehicle-treated ESS mice. Notably, BTZ-treated ESS mice showed markedly decreased Th17 cells, germinal center B cells and plasma cells in the peripheral lymphoid organs. In addition, adoptively transferred wild type naive CD4+ T cells rapidly differentiated into Th17 cells and induced salivary dysfunction in IL-17-deficient mice immunized for ESS induction. However, BTZ treatment profoundly suppressed the donor T-cell-derived Th17 response and ameliorated the reduction in salivary secretion in IL-17-deficient recipient mice. Taken together, our findings demonstrate that proteasome inhibition can effectively ameliorate ESS by suppressing the Th17 response, which may contribute to the development of a novel therapeutic strategy for the treatment of SS.Cellular &Molecular Immunology advance online publication, 10 July 2017; doi:10.1038/cmi.2017.8.

Treating the Underlying Pathophysiology of Primary Sjögren Syndrome: Recent Advances and Future Prospects

Sjögren Syndrome (SS) is a systemic autoimmune disease with a wide clinical spectrum that extends from sicca symptoms of the mucosal surfaces to extra-glandular systemic manifestations. Understanding of the pathophysiology of primary SS has advanced over recent years, and this, in turn, has presented new targeted treatment options. We provide a brief, up-to-date description of the pathophysiology of SS and the main etiopathogenic pathways implicated in the disease process and review clinical evidence in support of new treatment options targeting these pathways, highlighting successes and failures, and concluding with a summary of gaps in knowledge and where future research should be focused. Direct and indirect B-cell targeted therapies are currently the most promising biological agents in primary SS, especially for systemic involvement, but other pathways (T-cell co-stimulation, cytokine-based therapies, intracellular pathways and gene therapies) are under development. The next 10 years may witness a disruptive therapeutic scenario in primary SS.

Mechanisms and New Strategies for Primary Sjögren's Syndrome

Primary Sjögren's syndrome (SS) is a common chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands, mainly salivary and lacrimal, resulting in oral and ocular dryness, although virtually any organ system can be affected. SS-related systemic manifestations are classified as either related to the presence of periepithelial infiltrates in exocrine and parenchymal organs or resulting from immunocomplex deposition due to B cell hyperactivity with increased risk for B cell lymphoma development. Activation of both innate and adaptive immune pathways contributes to disease pathogenesis, with prominent interferon (IFN) signatures identified in both peripheral blood and affected salivary gland tissues. Recently, LINE-1 genomic repeat elements have been proposed as potential triggers of type I IFN pathway activation in SS through activation of Toll-like receptor-dependent and -independent pathways. In view of the increasingly appreciated variability of SS, elucidation of distinct operating pathways in relation to diverse clinical phenotypes and selection of the optimal therapeutic intervention remain major challenges. Inhibition of cathepsin S molecules, blockade of costimulation through administration of abatacept and inhibitors of B7-related molecules and CD40, blockade of B cell function and B cell survival factors, and disruption of the formation of ectopic germinal centers are considered the main therapeutic targets. Well-controlled multicenter clinical trials are ongoing and data are awaited.

Bortezomib for treatment of therapy-refractory anti-NMDA receptor encephalitis

OBJECTIVE

We assessed the therapeutic potential of the plasma-cell-depleting proteasome inhibitor bortezomib in severe and therapy-refractory cases of anti-NMDA receptor (anti-NMDAR) encephalitis.

METHODS

Five severely affected patients with anti-NMDAR encephalitis with delayed treatment response or resistance to standard immunosuppressive and B-cell-depleting drugs (corticosteroids, IV immunoglobulins, plasma exchange, immunoadsorption, rituximab, cyclophosphamide) who required medical treatment and artificial ventilation on intensive care units were treated with 1-6 cycles of 1.3 mg/m² bortezomib. Occurrence of adverse events was closely monitored.

RESULTS

Bortezomib treatment showed clinical improvement or disease remission, which was accompanied by a partial NMDAR antibody titer decline in 4 of 5 patients. With respect to disease severity, addition of bortezomib to the multimodal immunosuppressive treatment regimen was associated with an acceptable safety profile.

CONCLUSIONS

Our study identifies bortezomib as a promising escalation therapy for severe and therapy-refractory anti-NMDAR encephalitis.

CLASSIFICATION OF EVIDENCE

This retrospective case series provides Class IV evidence that bortezomib reduces antibody titers and improves the clinical course of patients with severe anti-NMDAR encephalitis.

Sjögren syndrome

Sjögren syndrome (SjS) is a systemic autoimmune disease that primarily affects the exocrine glands (mainly the salivary and lacrimal glands) and results in the severe dryness of mucosal surfaces, principally in the mouth and eyes. This disease predominantly affects middle-aged women, but can also be observed in children, men and the elderly. The clinical presentation of SjS is heterogeneous and can vary from sicca symptoms to systemic disease (characterized by peri-epithelial lymphocytic infiltration of the affected tissue or the deposition of the immune complex) and lymphoma. The mechanism underlying the development of SjS is the destruction of the epithelium of the exocrine glands, as a consequence of abnormal B cell and T cell responses to the autoantigens Ro/SSA and La/SSB, among others. Diagnostic criteria for SjS include the detection of autoantibodies in patient serum and histological analysis of biopsied salivary gland tissue. Therapeutic approaches for SjS include both topical and systemic treatments to manage the sicca and systemic symptoms of disease. SjS is a serious disease with excess mortality, mainly related to the systemic involvement of disease and the development of lymphomas in some patients. Knowledge of SjS has progressed substantially, but this disease is still characterized by sicca symptoms, the systemic involvement of disease, lymphocytic infiltration to exocrine glands, the presence of anti-Ro/SSA and anti-La/SSB autoantibodies and the increased risk of lymphoma in patients with SjS.