BAFF- and APRIL-targeted therapy in systemic autoimmune diseases

A Disintegrin and metalloproteinase carves T cell abnormalities and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder impacting various organs, notably prevalent in women of reproductive age. This review explores the involvement of a disintegrin and metalloproteinases (ADAMs) in SLE pathogenesis. Despite advancements in understanding SLE through genome and transcriptome studies, the role of ADAMs in post-translational regulations remains insufficiently explored. ADAMs, transmembrane proteins with diverse functions, impact cell adhesion, migration, and inflammation by shedding cell surface proteins, growth factors, and receptors. Notably, ADAM9 is implicated in Th17 cell differentiation, which is crucial in SLE pathology. ADAM10 and ADAM17 play pivotal roles in T-cell biology, influencing immune cell development and differentiation. Elevated soluble ADAM substrates in SLE patients serve as potential biomarkers correlating with disease activity. Targeting ADAMs or their substrates offers promising therapeutic avenues for SLE management and treatment enhancement.

Drugs in Development to Treat IgA Nephropathy

IgA nephropathy is a common glomerulonephritis consequent to the autoimmune response to aberrant glycosylated immunoglobulin (Ig) A antibodies. Although it has historically been considered a benign disease, it has since become clear that a substantial percentage of patients reach end-stage kidney failure over the years. Several therapeutic attempts have been proposed, with systemic steroids being the most prevalent, albeit burdened by possible serious adverse events. Thanks to the more in-depth knowledge of the pathogenesis of IgA nephropathy, new treatment targets have been identified and new drugs developed. In this narrative review, we summarise the molecules under clinical development for the treatment of IgA nephropathy. As a search strategy, we used PubMed, Google, ClinicalTrials.gov and abstracts from recent international congresses. TRF budesonide and sparsentan are the two molecules at a more advanced stage, just entering the market. Other promising agents are undergoing phase III clinical development. These include anti-APRIL and anti-BLyS/BAFF antibodies and some complement inhibitors. Other new possible strategies include spleen tyrosine kinase inhibitors, anti-CD40 ligands and anti-CD38 antibodies. In an era increasingly characterised by 'personalised medicine' and 'precision therapy' approaches and considering that the potential therapeutic armamentarium for IgA nephropathy will be very broad in the near future, the identification of biomarkers capable of helping the nephrologist to select the right drug for the right patient should be the focus of future studies.

B cell pathway dual inhibition for systemic lupus erythematosus: a prospective single-arm cohort study of telitacicept

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease associated with B-cell hyperactivity. Telitacicept is a transmembrane activator, calcium modulator, and cyclophilin ligand interactor-Fc fusion protein, which can neutralize both B-cell lymphocyte stimulator and a proliferation-inducing ligand. Patients with active SLE who received telitacicept were prospectively followed at month 1, 3, 6, 9, and 12 after telitacicept initiation. Thirty-seven participants were involved and followed for 6.00 [3.00, 6.00] months. SRI-4 rate at month 6 was 44.7%. The median dosage of prednisone was decreased by 43.8% (from 10 to 5.62 mg/d) at month 6. The anti-dsDNA level was significantly decreased, while complement levels were significantly increased at month 6 from baseline. Continuously significant reductions in serum immunoglobin (Ig)G IgA, and IgM levels were also observed. Patients experienced significant decreases in the numbers of total and naive B cells, whereas memory B cells and T cell populations did not change. The number of NK cells was significantly increased during the follow-up. At month 6, 58.3% (14 out of 24) patients experienced improved fatigue accessed by FACIT-Fatigue score exceeding the minimum clinically important difference of 4. Most adverse events were mild, but one each case of severe hypogammaglobulinemia, psychosis with suicidal behavior, and B-cell lymphoma were occurred. In our first prospective real-world study, telitacicept treatment led to a significant clinical and laboratory improvement of disease activity, as well as fatigue amelioration in patients with SLE. Safety profile was favorable overall, but more studies are greatly needed.

Spatial Transcriptomics Resolve an Emphysema-Specific Lymphoid Follicle B Cell Signature in Chronic Obstructive Pulmonary Disease

Rationale: Within chronic obstructive pulmonary disease (COPD), emphysema is characterized by a significant yet partially understood B cell immune component. Objectives: To characterize the transcriptomic signatures from lymphoid follicles (LFs) in ever-smokers without COPD and patients with COPD with varying degrees of emphysema. Methods: Lung sections from 40 patients with COPD and ever-smokers were used for LF proteomic and transcriptomic spatial profiling. Formalin- and O.C.T.-fixed lung samples obtained from biopsies or lung explants were assessed for LF presence. Emphysema measurements were obtained from clinical chest computed tomographic scans. High-confidence transcriptional target intersection analyses were conducted to resolve emphysema-induced transcriptional networks. Measurements and Main Results: Overall, 115 LFs from ever-smokers and Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1-2 and GOLD 3-4 patients were analyzed. No LFs were found in never-smokers. Differential gene expression analysis revealed significantly increased expression of LF assembly and B cell marker genes in subjects with severe emphysema. High-confidence transcriptional analysis revealed activation of an abnormal B cell activity signature in LFs (q-value = 2.56E-111). LFs from patients with GOLD 1-2 COPD with emphysema showed significantly increased expression of genes associated with antigen presentation, inflammation, and B cell activation and proliferation. LFs from patients with GOLD 1-2 COPD without emphysema showed an antiinflammatory profile. The extent of centrilobular emphysema was significantly associated with genes involved in B cell maturation and antibody production. Protein-RNA network analysis showed that LFs in emphysema have a unique signature skewed toward chronic B cell activation. Conclusions: An off-targeted B cell activation within LFs is associated with autoimmune-mediated emphysema pathogenesis.

Efficacy and safety of telitacicept in patients with systemic lupus erythematosus: a multicentre, retrospective, real-world study

OBJECTIVE

To examine the efficacy and safety of telitacicept in the treatment of patients with SLE in everyday clinical practice.

METHODS

Seventy-two patients with active SLE who received telitacicept for more than 24 weeks at multiple centres in China between 2019 and 2022 were retrospectively identified. Twenty-one of these patients received 52 continuous weeks of treatment with telitacicept. Treatment outcomes were analysed separately according to whether patients had renal or haematological abnormalities. Trajectory analysis was performed to identify patients with a limited response. Factors contributing to a limited response were explored by multivariable logistic regression analysis.

RESULTS

After treatment with telitacicept for 4, 12, 24 and 52 weeks, 22.22%, 54.17%, 72.22% and 80.95% of patients, respectively, achieved an SLE Responder Index 4; 8.33%, 26.39%, 34.72% and 47.62% achieved a Lupus Low Disease Activity State; and 0%, 4.17%, 8.33% and 23.81% achieved remission. Significant decreases in serum IgA, IgG and IgM levels were observed at 4 weeks and showed a downward trend at 12, 24 and 52 weeks. The median 24-hour urinary protein declined from 1323.5 mg to 224.0 mg in patients with lupus nephritis after treatment with telitacicept for 52 weeks. Furthermore, a large proportion of patients (10 of 13) with haematological abnormalities recovered after 52 weeks of treatment with telitacicept. No severe adverse events were reported during the observation period. Age appeared to have a negative impact on treatment efficacy.

CONCLUSIONS

Telitacicept demonstrated favourable efficacy and safety in patients with active SLE and improved the renal and haematological manifestations of the disease.

Genome-wide DNA methylation sequencing reveals epigenetic features and potential biomarkers of Sjögren syndrome

AIM

Sjögren syndrome (SS) is a slowly progressive, inflammatory, autoimmune disease. The aim of this study was to construct the DNA methylation profiles of whole blood of SS patients and healthy controls (HC), and to explore the role of differentially methylated genes in the pathogenesis of the disease.

METHODS

Whole-genome bisulfite sequencing was performed on three SS patients and four HC. The biological function of genes associated with differentially methylated regions (DMRs) was investigated using Gene Ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis, using network-based key driver analysis (KDA) to find KDA genes. In clinical samples of SS patients and controls, the expression levels of KDA genes were validated by quantitative real-time polymerase chain reaction and immunohistochemical analysis. Moreover, the diagnostic value of KDA genes for SS was confirmed using receiver operating characteristic curves.

RESULTS

We identified 322 DMRs, annotated as 162 associated genes. Six genes were selected via the number of networks of KDA genes. Differential expression of genes such as human leukocyte antigen (HLA) class I, ADAR, and OAS2 was observed in patients' peripheral blood mononuclear cells and the minor salivary glands, which can be used as potential diagnostic biomarkers for SS.

CONCLUSION

Clinical sample validation suggested that HLA class I, ADAR, and OAS2 might play a role in the development of SS. Our study shows epigenetic regulatory mechanisms and potential disease markers associated with SS, which in turn will enable us to identify new therapeutic targets.

The role of cross-reactive immunity to emerging coronaviruses: Implications for novel universal mucosal vaccine design

Host immune response to coronaviruses and the role of cross-reactivity immunity among different coronaviruses are crucial for understanding and combating the continuing COVID-19 outbreak and potential subsequent pandemics. This review paper explores how previous exposure to common cold coronaviruses and more pathogenic coronaviruses may elicit a protective immune response against SARS-CoV-2 infection, and discusses the challenges posed by some variants of concern that may escape current vaccines. It also highlights the need for a mucosal universal vaccine that can induce long-term protection against current and emerging coronaviruses by leveraging cross-reactive immunity. We propose a novel mucosal universal vaccine that consists of cross-reactive antigenic peptides with highly conserved epitopes among coronaviruses, conjugated with an immunostimulant adjuvant cytokine, including B-cell activating factor (BAFF). This vaccine may enhance the local mucosal adaptive response, induce tissue-resident memory cells, and inhibit viral replication and clearance. However, further research is required to evaluate its safety and efficacy.

Role of telitacicept in the treatment of IgA nephropathy

IgA nephropathy (IgAN) is the most common primary glomerular disease in the world, and up to 40% of patients with IgAN develop end-stage renal disease (ESRD). At present, an increasing amount of evidence indicates that the pathogenesis of IgAN is related to autoimmunity. In recent years, several studies have shown that B cell activating factors (BAFF), also known as B lymphocyte stimulators (BLyS), and proliferation-inducing ligand APRIL are extremely important for the activation of autoimmune signalling pathways, which have become key targets for the treatment of IgAN. As a dual-target biological agent, telitacicept can inhibit both BLyS and APRIL cytokines, improve the function of renal immune complexes, and reduce haematuria and proteinuria, which play important roles in IgAN pathogenesis and long-term prognosis. This article reviews the role of telitacicept in IgA nephropathy and discusses its potential for use in the treatment of IgAN and other autoimmune diseases where pathogenesis is driven by B cells.

Novel Therapeutic Strategies in the Treatment of Systemic Sclerosis

Systemic sclerosis is a connective tissue disease of unknown origin and with an unpredictable course, with both cutaneous and internal organ manifestations. Despite the enormous progress in rheumatology and clinical immunology, the background of this disease is largely unknown, and no specific therapy exists. The therapeutic approach aims to treat and preserve the function of internal organs, and this approach is commonly referred to as organ-based treatment. However, in modern times, data from other branches of medicine may offer insight into how to treat disease-related complications, making it possible to find new drugs to treat this disease. In this review, we present therapeutic options aiming to stop the progression of fibrotic processes, restore the aberrant immune response, stop improper signalling from proinflammatory cytokines, and halt the production of disease-related autoantibodies.

Immune Phenotype as a Biomarker for Systemic Lupus Erythematosus

The treatment of rheumatoid arthritis was revolutionized with the use of molecular-targeted drugs that target immunoregulatory molecules. The success of treatment with these drugs prompted the development of molecular-targeted drugs for systemic lupus erythematosus. However, systemic lupus erythematosus is a disease with high heterogeneous immune abnormalities, and diverse cells or molecules can be treatment targets. Thus, the identification of subpopulations based on immune abnormalities is essential for the development of effective treatment. One analytical method used to identify subpopulations is the immunophenotyping of peripheral blood samples of patients. This analysis evaluates the validity of target molecules for peripheral blood immune cell subsets, which are expected to be developed as biomarkers for precision medicine in which appropriate treatment targets are set for each subpopulation.

BAFF Promotes FLS Activation Through BAFFR-Mediated Non-canonical NF-κB Pathway and the Effects of CP-25

B cell activating factor (BAFF) has been shown to play a key role in regulating B cell function, but little is known about whether BAFF affects the function of fibroblast-like synoviocyte (FLS), an effector cell of rheumatoid arthritis (RA). CP-25, a new ester derivative of paeoniflorin, could alleviate the arthritis symptoms of collagen-induced arthritis (CIA) mice by inhibiting BAFF-mediated abnormal activation of B cells. In this study, we aimed to understand the mechanism by which BAFF activates FLS and the effect of CP-25 on FLS function. Therefore, the proliferation and migration abilities of FLS and key proteins on the non-canonical NF-κB pathway were examined. The results showed that compared with the FLS of normal rats/OA patients, the expression of BAFF-R, TRAF2, NIK, p-IKKα, P100, and P52 was higher in the FLS of AA rats/RA patients, while the expression of TRAF3 was lower. And, BAFF promotes FLS activation by activating the non-canonical NF-κB signaling pathway. Meanwhile, BAFFR-siRNA inhibited the proliferation of FLS and the activation of non-canonical NF-κB signaling in FLS induced by BAFF. Additionally, CP-25 could inhibit abnormal proliferation and migration of FLS by regulating non-canonical NF-κB signaling. We concluded that BAFF may act as an important role in facilitating the function of FLS through the BAFFR-mediated non-canonical NF-κB pathway, which would be useful for revealing the pathological mechanism of RA. And CP-25 may become a potential new drug for the treatment of RA, providing a scientific basis for the development of new drugs to treat RA.

Excess BAFF Alters NR4As Expression Levels and Breg Function of Human Precursor-like Marginal Zone B-Cells in the Context of HIV-1 Infection

We have reported excess B-cell activating factor (BAFF) in the blood of HIV-infected progressors, which was concomitant with increased frequencies of precursor-like marginal zone (MZp) B-cells, early on and despite antiretroviral therapy (ART). In controls, MZp possess a strong B-cell regulatory (Breg) potential. They highly express IL-10, the orphan nuclear receptors (NR)4A1, NR4A2 and NR4A3, as well as the ectonucleotidases CD39 and CD73, all of which are associated with the regulation of inflammation. Furthermore, we have shown MZp regulatory function to involve CD83 signaling. To address the impact of HIV infection and excessive BAFF on MZp Breg capacities, we have performed transcriptomic analyses by RNA-seq of sorted MZp B-cells from the blood of HIV-infected progressors. The Breg profile and function of blood MZp B-cells from HIV-infected progressors were assessed by flow-cytometry and light microscopy high-content screening (HCS) analyses, respectively. We report significant downregulation of NR4A1, NR4A2, NR4A3 and CD83 gene transcripts in blood MZp B-cells from HIV-infected progressors when compared to controls. NR4A1, NR4A3 and CD83 protein expression levels and Breg function were also downregulated in blood MZp B-cells from HIV-infected progressors and not restored by ART. Moreover, we observe decreased expression levels of NR4A1, NR4A3, CD83 and IL-10 by blood and tonsillar MZp B-cells from controls following culture with excess BAFF, which significantly diminished their regulatory function. These findings, made on a limited number of individuals, suggest that excess BAFF contributes to the alteration of the Breg potential of MZp B-cells during HIV infection and possibly in other situations where BAFF is found in excess.

B cell-targeted therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that primarily affects women of childbearing age. There is no disease more heterogeneous than SLE as patients experience a myriad of manifestations and unpredictable periods of heightened disease activity. This heterogeneity not only makes it difficult for treatment decisions and prognostication, but has made drug development quite challenging. Despite these challenges, belimumab, voclosporin, and anifromulab, approved by the United States Food and Drug Administration (FDA) to treat SLE or lupus nephritis (LN), enhanced our armamentarium of traditional therapies, such as hydroxychloroquine, corticosteroids, and immunosuppressives. However, there remains a dire need to develop therapies that offer greater efficacy and safety. Patients with SLE produce excessive amounts of autoantibodies and cytokines that result in inflammation and organ damage. While a considerable number of potential drug development targets exist, there has been much attention focused on B cells. Strategies have included direct B cell killing, modulation of B cell function, inhibition of molecules essential to B cell growth and survival, and acceleration of autoantibody clearance, to name just a few. In this article, we review SLE clinical trials evaluating experimental agents that target B cells or plasma cells.

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.

Anti-CD20 therapy ameliorates β cell function and rebalances Th17/Treg cells in NOD mice

PURPOSE

Anti-CD20 therapy delays type 1 diabetes mellitus (T1DM) progression in both nonobese diabetic (NOD) mice and new-onset patients. The mechanism is not completely defined. This study aimed to investigate the effects of anti-CD20 therapy on T helper 17 (Th17) cells and regulatory T cells (Tregs) in NOD mice. The role of B cell depletion in T1DM development was also examined.

METHODS

NOD mice were randomly divided into two groups. The mice in the experimental group were treated with an anti-CD20 antibody, while the control mice were treated with an isotype-matched control antibody. After treatment, islet morphology and inflammation, Th17 and Treg cell frequencies in the pancreas and spleen, serum cytokine and anti-glutamic acid decarboxylase (GAD) antibody levels, interleukin (IL)-17A levels in the pancreas and spleen, insulin expression in islet cells and islet β cell function were measured.

RESULTS

Decreased blood glucose and increased insulin secretion were found in the exprimental group compared with the CON group. A lower islet inflammation score was also found in the experimental group. Decreased Th17 cell and IL-17A levels and augmented Treg cell levels were found in the spleen and pancreas after anti-CD20 treatment. The serum levels of B cell activating factor (BAFF), IL-17A, IL-17F, IL-23 and anti-GAD autoantibodies were decreased in the experimental group, while higher serum levels of IL-10 and transforming growth factor (TGF)-β were found.

CONCLUSION

Anti-CD20 therapy might have some beneficial effects that improve β cell function by relieving islet inflammation through regulation of Th17/Treg cells and the proinflammatory/anti-inflammatory balance.

Treatment of Autoimmune Diseases with Therapeutic Antibodies: Lessons Learned from PID Patients Allow for Stratification of the Infection Risk

Over the years, a wide variety of therapeutic antibodies has been successfully introduced in the autoimmunology clinic and many more are on the edge to follow. Many of these treatments address either a pathogenic circulating molecule or a cell-bound molecule. Whereas the former target results in neutralization of the soluble factor, the latter target either inhibits cellular function or induces selective cell death. If this targeted molecule or cell is part of the immune system, this therapy evokes a state of immunodeficiency. Knowing the exact function of the respective components enables the risk stratification for possible infectious complications in patients treated with biologics. Much of the understanding of the function of immune cells and their associated molecules, in relation to redundancy in the immune system, is derived from studies in knockout mice. However, as mice are not men in terms of their life-expectancy, their infection exposure, or the composition of their immune system, the most useful knowledge for estimating the consequence of therapeutic intervention on immune competence comes from monitoring patients. In the current chapter, we focus on patients with a primary immunodeficiency (PID) because they provide us with a unique perspective to estimate the redundancy of a certain genetic defect for overall immune competence. These patients have inborn errors of the immune system that, in general, are due to single gene defects. Depending on the immunological pathway that is defective, patients can present with different types of (opportunistic) infectious diseases, as well as other clinical manifestations. Based on selected examples, we focus in this chapter on finding parallels in the infectious risk of autoimmune patients treated with biologics and PID patients with a defect in the immunological pathway that is affected by the respective biologic. The goal is to learn from the (dis)similarities between both patient populations in terms of safety profiles of biologic treatments.

Review article: targeting the B cell activation system in autoimmune hepatitis

BACKGROUND

The B cell activation system, consisting of B cell activating factor and a proliferation-inducing ligand, may have pathogenic effects in autoimmune hepatitis.

AIMS

To describe the biological actions of the B cell activation system, indicate its possible role in autoimmune diseases, and evaluate its prospects as a therapeutic target in autoimmune hepatitis METHODS: English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed.

RESULTS

The B cell activating factor is crucial for the maturation and survival of B cells, and it can co-stimulate T cell activation, proliferation, and survival. It can also modulate the immune response by inducing interleukin 10 production by regulatory B cells. A proliferation-inducing ligand modulates and diversifies the antibody response by inducing class-switch recombination in B cells. It can also increase the proliferation, survival, and antigen activation of T cells. These immune stimulatory actions can be modulated by inducing proliferation of regulatory T cells. The B cell activation system has been implicated in diverse autoimmune diseases, and therapeutic blockade is a management strategy now being evaluated in autoimmune hepatitis.

CONCLUSIONS

The B cell activation system has profound effects on B and T cell function in autoimmune diseases. Blockade therapy is being actively evaluated in autoimmune hepatitis. Clarification of the critical pathogenic components of the B cell activation system will improve the targeting, efficacy, and safety of blockade therapy in this disease.

Lower BAFF Levels in Myasthenic Patients Treated with Glucocorticoids

B-cell activating factor (BAFF), a member of tumor necrosis factor family, activates B cells, promotes their survival and proliferation. BAFF is considered to have an influence on development of autoimmune diseases including myasthenia gravis (MG). We aimed to evaluate BAFF serum levels in MG patients, their potential connection with therapy and course of MG. Cross-sectional study. Two hundred eighteen adult patients with MG (67% women, age: 18-89 years, 82.6% AChR antibody seropositive (AChRAb(+)). Serum BAFF levels, their relationship with severity of clinical symptoms, therapy conducted, clinical and demographic features and other factors were analyzed. Patients with AChRAb(+) MG demonstrated significantly higher BAFF levels than MuSK-MG patients (831.2 ± 285.4 pg/ml vs. 745.6 ± 633.4 pg/ml, respectively; p = 0.030). Serum BAFF levels in women were significantly higher than in men (855.9 ± 302.5 vs. 756.6 ± 289.4, respectively; p = 0.017). Mean serum BAFF level was significantly decreased in patients who were ever treated with corticosteroids (CS) (770.4 ± 327.8 pg/ml vs. 891.3 ± 246.1 pg/ml, respectively; p = 0.001). Thymoma-MG patients demonstrated significantly lower BAFF levels (671.2 ± 244.9 vs. 833.5 ± 302.4, respectively; p = 0.044). Thymectomized patients did not differ in BAFF levels from the MG patients who had not undergone thymectomy. In multiple linear regression model, recent CS therapy and male sex were found to be independent predictors of lower BAFF levels. Serum BAFF level is decreased in patients treated with CS, which may suggest inhibiting influence of CS on BAFF-a potential mechanism contributing to the effectiveness of such therapy.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The “variable” aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren’s syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better “autoimmune” association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

Approaches for Controlling Antibody-Mediated Allograft Rejection Through Targeting B Cells

Both acute and chronic antibody-mediated allograft rejection (AMR), which are directly mediated by B cells, remain difficult to treat. Long-lived plasma cells (LLPCs) in bone marrow (BM) play a crucial role in the production of the antibodies that induce AMR. However, LLPCs survive through a T cell-independent mechanism and resist conventional immunosuppressive therapy. Desensitization therapy is therefore performed, although it is accompanied by severe side effects and the pathological condition may be at an irreversible stage when these antibodies, which induce AMR development, are detected in the serum. In other words, AMR control requires the development of a diagnostic method that predicts its onset before LLPC differentiation and enables therapeutic intervention and the establishment of humoral immune monitoring methods providing more detailed information, including individual differences in the susceptibility to immunosuppressive agents and the pathological conditions. In this study, we reviewed recent studies related to the direct or indirect involvement of immunocompetent cells in the differentiation of naïve-B cells into LLPCs, the limitations of conventional methods, and the possible development of novel control methods in the context of AMR. This information will significantly contribute to the development of clinical applications for AMR and improve the prognosis of patients who undergo organ transplantation.

Circulating plasmablasts and high level of BAFF are hallmarks of minimal change nephrotic syndrome in adults

BACKGROUND

The recent success achieved with the use of B cell-depleting agents in some patients with minimal change nephrotic syndrome (MCNS) suggests an unexpected role for B lymphocytes in the pathogenesis of this immune-mediated glomerular disease. Nevertheless, no extensive B-cell phenotyping analysis has ever been performed in untreated adult patients soon after MCNS diagnosis.

METHODS

We investigated the distribution of the different B-cell subpopulations in 22 untreated adult patients with biopsy-proven MCNS [MCNS relapse (MCNS-Rel)]. We compared these data with those for 24 healthy controls, 13 MCNS patients in remission (with no specific treatment) and 19 patients with idiopathic membranous nephropathy (IMN).

RESULTS

Patients with MCNS-Rel or IMN had higher proteinuria and lower serum albumin and gammaglobulin levels (P < 0.0001 for all comparisons) than MCNS patients in remission. Plasmablasts were the only B-cell subsets present at significantly higher levels in MCNS-Rel patients than in the patients of the other three groups (P < 0.05 for all comparisons). The lower albumin levels and higher proteinuria levels were positively correlated with the percentage of circulating plasmablasts (Spearman test's ρ = -0.54, P = 0.01 and ρ = 0.65, P = 0.002, respectively). Similarly, the increase of immunoglobulin M (IgM) and the decrease of IgG levels were significantly associated with the percentage of plasmablasts in MCNS-Rel patients (Spearman's ρ = 0.36, P = 0.01 and Spearman's ρ = -0.60, P = 0.01, respectively). Increased production of interleukin (IL)-21, IL-6 and B-cell activating factor (BAFF) in the serum of MCNS-Rel patients was found significantly correlated with the percentage of plasmablasts (ρ = 0.72, P = 0.0002, ρ = 0.49, P = 0.04 and ρ = 0.62, P = 0.009, respectively).

CONCLUSIONS

An increase in the proportion of circulating plasmablasts seems to be a hallmark of untreated MCNS in adult patients. Further studies are required to more precisely determine the phenotype and functions of these cells.

The clinical efficacy of Rituximab administration in autoimmunity disorders, primary immunodeficiency diseases and malignancies

Rituximab (RTX), as a monoclonal antibody-based immunotherapeutic intervention targeting CD20 on B cells, has proven efficacy in the treatment of patients with some immune-mediated diseases. In the present review, we provided information on the immunobiological mechanisms of signaling for RTX and its clinical applications, according to the immune-pathophysiology involved in the microenvironment of multiple diseases. We highlighted combination therapy, dose schedules, and laboratory monitoring, as well as the associated common and rare side effects to avoid. We also discussed the efficacy and safety of RTX-based therapeutic strategies and whether RTX therapy can be used as a promising treatment regimen for autoimmune diseases, primary immunodeficiency diseases, and malignancies. Our review highlights and supports the importance of collaboration between basic medical researchers and clinical specialists when considering the use of RTX in the treatment of various immune-mediated disorders.

Belimumab: a step forward in the treatment of systemic lupus erythematosus

Introduction: Systemic Lupus Erythematosus (SLE) is a chronic B cell-mediated autoimmune disease which can potentially involve several organs and systems. The development of SLE is associated with a complexity of genetic, hormonal and environmental factors leading to immune deregulation and production of autoantibodies. Therefore, novel therapies have focused on B cells as key effectors of SLE pathogenesis. Belimumab is a fully humanized monoclonal antibody that antagonizes B-lymphocyte stimulator (BLyS); it is the first and the only biological drug approved for SLE in over 50 years.Areas covered: In this review we discuss the pharmacological properties of belimumab, new recommendations for its use in clinical practice and its evidence of efficacy and safety based on clinical trial and real-life data.Expert opinion: Efficacy and safety of belimumab in clinical practice have been well established. To date, it is known that early introduction of belimumab in SLE can maximize the efficacy of the drug. A number of questions are still open, such as the timing of belimumab discontinuation and its possible association with other biological drugs, which need to be assessed in future studies.

Emerging Modes of Treatment of IgA Nephropathy

IgA nephropathy is the most common primary glomerulonephritis with potentially serious outcome leading to end stage renal disease in 30 to 50% of patients within 20 to 30 years. Renal biopsy, which might be associated with risks of complications (bleeding and others), still remains the only reliable diagnostic tool for IgA nephropathy. Therefore, the search for non-invasive diagnostic and prognostic markers for detection of subclinical types of IgA nephropathy, evaluation of disease activity, and assessment of treatment effectiveness, is of utmost importance. In this review, we summarize treatment options for patients with IgA nephropathy including the drugs currently under evaluation in randomized control trials. An early initiation of immunosupressive regimens in patients with IgA nephropathy at risk of progression should result in the slowing down of the progression of renal function to end stage renal disease.

A Comprehensive Review of Biological Agents for Lupus: Beyond Single Target

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple immune cells. Due to its complex pathogenesis, the effectiveness of traditional treatment methods is limited. Many patients have developed resistance to conventional treatment or are not sensitive to steroid and immunosuppressant therapy, and so emerging therapeutic antibodies have become an alternative and have been shown to work well in many patients with moderate and severe SLE. This review summarizes the biological agents that are in the preclinical and clinical trial study of SLE. In addition to the various monoclonal antibodies that have been studied for a long time, such as belimumab and rituximab, we focused on another treatment for SLE, bispecific antibodies (BsAbs) such as tibulizumab, which simultaneously targets multiple pathogenic cytokines or pathways. Although the application of BsAbs in cancer has been intensively studied, their application in autoimmune diseases is still in the infant stage. This unique combined mechanism of action may provide a novel therapeutic strategy for SLE.

Soluble ligands as drug targets

Historically, the main classes of drug targets have been receptors, enzymes, ion channels and transporters. However, owing largely to the rise of antibody-based therapies in the past two decades, soluble protein ligands such as inflammatory cytokines have become an increasingly important class of drug targets. In this Review, we analyse drugs targeting ligands that have reached clinical development at some point since 1992. We identify 291 drugs that target 99 unique ligands, and we discuss trends in the characteristics of the ligands, drugs and indications for which they have been tested. In the last 5 years, the number of ligand-targeting drugs approved by the FDA has doubled to 34, while the number of clinically validated ligand targets has doubled to 22. Cytokines and growth factors are the predominant types of targeted ligands (70%), and inflammation and autoimmune disorders, cancer and ophthalmological diseases are the top therapeutic areas for both approved agents and agents in clinical studies, reflecting the central role of cytokine and/or growth factor pathways in such diseases.

The TNFSF Members APRIL and BAFF and Their Receptors TACI, BCMA, and BAFFR in Oncology, With a Special Focus in Breast Cancer

Tumor necrosis factor (TNF) superfamily consists of 19 ligands and 29 receptors and is related to multiple cellular events from proliferation and differentiation to apoptosis and tumor reduction. In this review, we overview the whole system, and we focus on A proliferation-inducing ligand (APRIL, TNFSF13) and B cell-activating factor (BAFF, TNFSF13B) and their receptors transmembrane activator and Ca²⁺ modulator (CAML) interactor (TACI, TNFRSF13B), B cell maturation antigen (BCMA, TNFRSF17), and BAFF receptor (BAFFR, TNFRSF13C). We explore their role in cancer and novel biological therapies introduced for multiple myeloma and further focus on breast cancer, in which the modulation of this system seems to be of potential interest, as a novel therapeutic target. Finally, we discuss some precautions which should be taken into consideration, while targeting the APRIL–BAFF system.

B cells targeting therapy in the management of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease which affects the majority of organs and systems. Traditional therapies do not lead to complete remission of disease but only relieve symptoms and inflammation. B cells are the most important effector cell types in the pathogenesis of SLE. Therefore, therapies targeting B cells and their related cytokines are a very important milestone for SLE treatment. Several biologics that modulate B cells, either depleting B cells or blocking B cell functions, have been developed and evaluated in clinical trials. Belimumab, a fully humanized monoclonal antibody that specifically binds B cells activating factor (BAFF), was the first of these agents approved for SLE treatment. In this review, we explore the currently available evidence in B cell targeted therapies in SLE including agents that target B cell surface antigens (CD19, CD20, CD22), B cell survival factors (BAFF and a proliferation-inducing ligand, APRIL), cytokines (interleukin-1 and type 1 interferons) and co-stimulatory molecules (CD40 ligand). We highlighted the mechanisms of action and the individual characteristics of these biologics, and present an update on the clinical trials that have evaluated their efficacy and safety. Finally, we describe some of the emerging and promising therapies for SLE treatment.

Silencing of the cytokine receptor TNFRSF13B: A new therapeutic target for triple-negative breast cancer

BACKGROUND

TNFRSF13B, TACI, is a member of the TNF receptor superfamily; it plays a key role in cancer cell proliferation and progression.

METHOD

Influence of silencing of human cytokine receptors on cell viability was screened by Luminescent Cell Viability Assay, after transfection of the siRNA library to find the maximum cell death superhits in both triple-negative MDA-MB-231 and double-positive MCF7 breast cells. The mode of cell death was investigated by dual DNA fluorescence staining. The expression of mRNAs of TACI, BAFF, BAFF-R, and APRIL was explored by qPCR. Immunocytofluorescence analysis was used to evaluate changes in TACI, Bcl-2, TNFR2, cyclin-D2, and PCNA. NF-kB p65, cell cycle, and necrosis/apoptosis (late and early) were analyzed by flow cytometry.

RESULTS

TACI is the most potent cytotoxic superhit resulted from high-throughput screening of the siRNA library, in both types of cells. Our findings indicated that silencing receptor TACI in both types of breast cancer cells led to significant cell death, after different intervals from siRNA transfection. Cell death mediators (TNFR2, Bcl-2, and NF-κB) were significantly decreased after TACI silencing. The key factors for cell division (Cyclin-D2 and PCNA) were significantly increased in silenced cells of both types but the cell cycle was arrested before the completion of mitosis. Expression of BAFF, BAFF-R and APRIL mRNA in TACI-silenced cells showed significant upregulation in MDA-MB-231 cells, while only BAFF-R and APRIL showed significant downregulation in MCF7 cells.

CONCLUSION

TACI silencing can be a new and promising therapeutic target for mesenchymal-stem like triple-negative breast cancer subtype.

A comprehensive review of rituximab therapy in rheumatoid arthritis patients

Rituximab (RTX) is an approved treatment for rheumatoid arthritis (RA) patients that do not respond adequately to disease-modifying antirheumatic drugs. However, different new concerns, such as efficacy, optimum dose, safety issues, prediction of response to RTX, and pregnancy outcomes have attracted a lot of attention. The PubMed database was systematically reviewed for the last published articles, new findings, and controversial issues regarding RTX therapy in RA using "Rheumatoid arthritis" AND "rituximab" keywords, last updated on June 18, 2019. From 1812 initial recorders, 162 studies met the criteria. Regarding the optimum dose, low-dose RTX therapy (2 × 500 mg) seems as effective as standard dose (2 × 1000 mg), safer, and more cost-effective. The most common reported safety challenges included de novo infections, false negative serologic tests of viral infections, reactivation of chronic infections, interfering with vaccination outcome, and development of de novo psoriasis. Other less reported side effects are infusion reactions, nervous system disorders, and gastrointestinal disorders. Lower exposure to other biologics, presence of some serological markers (e.g., anti-RF, anti-CCP, IL-33, ESR), specific variations in FCGR3A, FCGR2A, TGFβ1, IL6, IRF5, BAFF genes, and also EBV-positivity could be used to predict response to RTX. Although there is no evidence of the teratogenic effect of RTX, it is recommended that women do not expose themselves to RTX at least 6 months before the conception. Only a reversible reduction of B cell-count in the offspring may be the pregnancy-related outcome. Although RTX is an effective therapeutic option for RA, more studies on optimum doses, prevention of RTX-related side effects, prediction of RTX response, and safety during the pregnancy are required.

Small-molecule inhibitors and the salivary gland epithelium in Sjögren's syndrome

INTRODUCTION

The salivary gland (SG) in primary Sjögren's syndrome (pSS) is characterized by its lack of function (hyposalivation) and lymphocytic invasion. Small-molecule inhibitors (SMIs) are a new class of drugs, whose diminutive size permits diffusion into cells. SMIs targeting components of the immune system are eagerly being trialed for their potential therapeutic utility in pSS. Neglected until now, however, is a discussion of the potential effects of SMIs on the SG epithelium.

AREAS COVERED

We begin by reminding the reader of the SG epithelial compartment, its complicity in inflammatory milieu formation in pSS, and categories of SMIs which merit attention. We discuss each SMI category, including pre-clinical data concerning pSS and likely consequences of their application on the SG epithelium.

EXPERT OPINION

Recovery of saliva production in pSS requires restoring the function of the SG epithelium, not solely on inflammation resolution. Many SMIs, for example, those blocking JAK-STAT signaling, interfere with critical epithelial cell pathways, most notably EGF signaling. If the effect of SMIs on SG epithelium is ignored, recovery of SG function will be challenging. We predict that NFκB signaling blockade will impart the least SG epithelium damage whilst reducing inflammation and facilitating recovery from hyposalivation in pSS.

Local Cytokine Expression Profiling in Patients with Specific Autoimmune Uveitic Entities

Purpose: To evaluate expression of cytokines GM-CSF, IL-11, IL-12p40, IL-12p70, IL-27p28, IL-35, APRIL, BAFF, TWEAK, and LIGHT in uveitis.Methods: Aqueous humor samples from patients with active uveitis associated with Behçet's disease (BD), sarcoidosis, HLA-B27-related inflammation, and Vogt-Koyanagi-Harada (VKH) disease and control patients were assayed with a multiplex assay.Results: Comparing all patients to controls, GM-CSF, IL-11, IL-12p40, APRIL, and BAFF were significantly increased, whereas LIGHT was significantly decreased. IL-11 and BAFF were the most strongly upregulated, being elevated 19.7-fold and 14.1-fold, respectively, compared with controls. IL-11 was significantly highest in HLA-B27 uveitis. GM-CSF, IL-11, and IL-12p40 were significantly higher in nongranulomatous uveitis (BD and HLA-B27) than in granulomatous uveitis (sarcoidosis and VKH), whereas APRIL and TWEAK were significantly higher in granulomatous uveitis.Conclusions: IL-11-driven immune responses might be more potent in nongranulomatous uveitis, particularly in HLA-B27 uveitis. BAFF and APRIL might contribute to B cell-driven autoimmune response in uveitis.

Monoclonal Antibodies for the Treatment of Multiple Myeloma: An Update

The past two decades have seen a revolution in multiple myeloma (MM) therapy with the introduction of several small molecules, mostly orally effective, whose mechanisms are based on proteasome inhibition, histone deacetylase (HDAC) blockade, and immunomodulation. Immunotherapeutic approaches to MM treatment using monoclonal antibodies (mAbs), while long in development, began to reap success with the identification of CD38 and SLAMF7 as suitable targets for development, culminating in the 2015 Food and Drug Administration (FDA) approval of daratumumab and elotuzumab, respectively. This review highlights additional mAbs now in the developmental pipeline. Isatuximab, another anti-CD38 mAb, currently is under study in four phase III trials and may offer certain advantages over daratumumab. Several antibody-drug conjugates (ADCs) in the early stages of development are described, including JNJ-63723283, which has attained FDA breakthrough status for MM. Other mAbs described in this review include denosumab, recently approved for myeloma-associated bone loss, and checkpoint inhibitors, although the future status of the latter combined with immunomodulators has been clouded by unacceptably high death rates that caused the FDA to issue clinical holds on several of these trials. Also highlighted are the therapies based on the B Cell Maturation Antigen (BCMA), another very promising target for anti-myeloma development.

Increased genomic instability following treatment with direct acting anti-hepatitis C virus drugs

Mixed Cryoglobulinemic Vasculitis (MCV) is a prominent extra-hepatic manifestation of Hepatitis C virus (HCV) infection. HCV has been reported to cause B-cell disorders and genomic instability. Here, we investigated B-cell activation and genome stability in HCV-MCV patients receiving the direct antiviral agent, Sofosbuvir, at multiple centers in Egypt. Clinical manifestations in HCV-MCV patients were improved at the end of treatment (EOT), such as purpura (100%), articular manifestations (75%) and neuropathy (68%). Eighteen patients (56%) showed vasculitis relapse after EOT. BAFF and APRIL were higher at EOT and continued to increase one year following treatment onset. Chromosomal breaks were elevated at EOT compared to baseline levels and were sustained at 3 and 6 months post treatment. We report increased expression of DNA genome stability transcripts such as topoisomerase 1 and TDP1 in HCV-MCV patients after treatment, which continued to increase at 12 months from treatment onset. This data suggest that B-cell activation and DNA damage are important determinants of HCV-MCV treatment outcomes.

TLR7/TLR9- and B Cell Receptor-Signaling Crosstalk: Promotion of Potentially Dangerous B Cells

B cells are capable of receptor-mediated responses to foreign antigens. Recognition of microbial-derived nucleic acid (NA) by toll-like receptors (TLRs) 7 and 9 in B cells has been substantiated. Endogenous NA released from damaged or dying cells can also be immunogenic in certain contexts and can incite aberrant activation of B cells. When TLR-driven B cell receptor (BCR)-activated B cells are not properly constrained, pathologic autoantibodies are produced. It is also clear that endosomal TLR7/TLR9 can operate in conjunction with BCR. In addition to BCR signaling, a balance between TLR7 and TLR9 is pivotal in the development of B cell autoreactivity. While TLR9 is important in normal memory B cell responses through BCR, TLR9 activation has been implicated in autoantibody production. Paradoxically, TLR9 also plays known protective roles against autoimmunity by directly and indirectly inhibiting TLR7-mediated autoantibody production. Herein, we summarize literature supporting mechanisms underpinning the promotion of pathological BCR-activated B cells by TLR7 and TLR9. We focus on the literature regarding known points of TLR7/TLR9 and BCR crosstalk. Data also suggest that the degree of TLR responsiveness relies on alterations of certain intrinsic B-cell signaling molecules and is also context specific. Because allogeneic hematopoietic stem cell transplantation is a high NA and B cell-activating factor environment, we conclude that B cell studies of synergistic TLR-BCR signaling in human diseases like chronic graft-versus-host disease are warranted. Further understanding of the distinct molecular pathways mediating TLR-BCR synergy will lead to the development of therapeutic strategies in autoimmune disease states.