Cracking the BAFF code. Nat Rev Immunol. 2009;9:491-502. [PMID: 19521398 DOI: 10.1038/nri2572]

State of pneumococcal vaccine immunity

Like the other invasive encapsulated bacteria, Streptococcus pneumoniae is also covered with a polysaccharide structure. Infants and elderly are most vulnerable to the invasive and noninvasive diseases caused by S. pneumoniae. Although antibodies against polysaccharide capsule are efficient in eliminating S. pneumoniae, the T cell independent nature of the immune response against polysaccharide vaccines renders them weakly antigenic. The introduction of protein conjugated capsular polysaccharide vaccines helped overcome the weak immunogenicity of pneumococcal polysaccharides and decreased the incidence of pneumococcal diseases, especially in pediatric population. Conjugate vaccines elicit T cell dependent response which involve the interaction of specialized CD4+ T cells, called follicular helper T cells (Tfh) with germinal center B cells in secondary lymphoid organs. Despite their improved immunogenicity, conjugate vaccines still need to be administered three to four times in infants during the first 15 month of their life because they mount poor Tfh response. Recent studies revealed fundamental differences in the generation of Tfh cells between neonates and adults. As the portfolio of pneumococcal conjugate vaccines continues to increase, better understanding of the mechanisms of antibody development in different age groups will help in the development of pneumococcal vaccines tailored for different ages.

Serum BAFF levels are associated with the prognosis of idiopathic membranous nephropathy

OBJECTIVE

High serum levels of B-cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL) have been observed in patients with idiopathic membranous nephropathy (iMN); however, their relationships with disease severity and progression remain unclear.

METHODS

Patients with iMN diagnosed via renal biopsy were enrolled in this study. The concentrations of BAFF and APRIL were determined using ELISA kits. Proteinuria remission, including complete remission (CR) and partial remission (PR), and renal function deterioration were defined as clinical events. The Cox proportional hazards method was used to analyze the relationship between cytokine levels and disease progression.

RESULTS

Seventy iMN patients were enrolled in this study, with a median follow-up time of 24 months (range 6-72 months). The serum levels of BAFF and APRIL were higher in iMN patients than in healthy controls but lower than those in minimal change disease (MCD) patients. The serum BAFF level was positively correlated with the serum APRIL level, serum anti-phospholipase A2 receptor (anti-PLA2R) antibody level, and 24-h proteinuria and negatively correlated with the serum albumin (ALB) level. However, no significant correlation was observed between the serum APRIL level and clinical parameters. According to the multivariate Cox proportional hazards regression model adjusted for sex, age, systolic blood pressure (SBP), estimated glomerular filtration rate (eGFR), immunosuppressive agent use, 24-h proteinuria, APRIL level, and anti-PLA2R antibody, only the serum BAFF level was identified as an independent predictor of PR (HR, 0.613; 95% CI, 0.405-0.927; p = 0.021) and CR of proteinuria (HR, 0.362; 95% CI, 0.202-0.648; p < 0.001).

CONCLUSIONS

A high serum BAFF level is associated with severe clinical manifestations and poor disease progression in patients with iMN.

Microbe-associated molecular patterns derived from fungi and bacteria promote IgG4 antibody production in patients with type 1 autoimmune pancreatitis

Enhanced IgG4 antibody (Ab) response is a prominent feature of type 1 autoimmune pancreatitis (AIP). Innate immune responses associated with IgG4 Ab production are poorly defined. We have previously reported that peripheral blood mononuclear cells (PBMCs) isolated from patients with type 1 AIP produce large amounts of IgG4 Abs upon stimulation with bacterial cell wall components. In addition, we showed that activation of plasmacytoid dendritic cells producing interferon (IFN)-α, interleukin (IL)-33, and B cell-activating factor (BAFF) upon sensing intestinal bacteria mediates the development of experimental AIP. In this study, we attempted to clarify the role of innate immunity against fungi in inducing enhanced IgG4 Ab responses in type 1 AIP. PBMCs isolated from healthy controls and patients with type 1 AIP were stimulated with a broad range of bacterial and fungal cell wall components. The concentrations of IgG1, IgG4, and cytokines were measured using enzyme-linked immunosorbent assays. Cell wall components derived from bacteria and fungi induced IgG1 and IgG4 Ab production in patients with type 1 AIP. Various types of microbe-associated molecular pattern motifs enhanced IgG4 Ab production in patients with type 1 AIP compared with the limited motifs in healthy controls. The enhanced IgG1 and IgG4 Ab production that followed in response to bacterial and fungal cell wall components was parallel to that of IFN-α, IFN-γ, IL-10, IL-33, and BAFF. In conclusion, cell wall components derived from fungi as well as bacteria promote IgG4 Ab responses in patients with type 1 AIP.

Current status of BAFF targeting immunotherapy in B-cell neoplasm

B-cell activating factor belonging to the TNF family (BAFF), also known as B-lymphocyte stimulator (BLyS), plays a crucial role in B-cell development. It has multiple receptors, including BCMA, TACI, and BAFF-R, with diverse roles in different cell types. BAFF induces B-cell proliferation and immunoglobulin secretion, and acts as a survival factor for immature, naive, and activated B cells. Consequently, BAFF-deficient mice often show suppressed humoral responses, while BAFF-overexpressing mice show the higher number of mature B cells and may develop autoimmune-like manifestations and B-cell lymphoproliferative diseases. Elevated BAFF levels are also associated with various hematological malignancies, and its expression correlates with disease progression in some cases. Therefore, BAFF-targeted therapies, such as belimumab, atacicept, and tabalumab, are being explored in clinical trials for conditions like chronic lymphocytic leukemia (CLL) and multiple myeloma. Belimumab, an anti-BAFF monoclonal antibody, is being investigated in combination with rituximab/venetoclax for CLL. Atacicept, a decoy receptor for BAFF and APRIL, showed tolerability in a phase 1b trial for CLL. Tabalumab, another monoclonal antibody targeting BAFF, did not demonstrate significant efficacy in a phase 2 study for relapsed/refractory multiple myeloma. BAFF ligand-based CAR-T cells are designed to target BAFF receptors and show promise in preclinical studies, particularly for B-cell malignancies. The review emphasizes the importance of understanding the roles of BAFF and its receptors in the microenvironment of hematologic malignancies. Targeting BAFF and its receptors presents potential therapeutic avenues, and ongoing clinical trials provide valuable insights.

Innate Immune Cells in Melanoma: Implications for Immunotherapy

The innate immune system, composed of neutrophils, basophils, eosinophils, myeloid-derived suppressor cells (MDSCs), macrophages, dendritic cells (DCs), mast cells (MCs), and innate lymphoid cells (ILCs), is the first line of defense. Growing evidence demonstrates the crucial role of innate immunity in tumor initiation and progression. Several studies support the idea that innate immunity, through the release of pro- and/or anti-inflammatory cytokines and tumor growth factors, plays a significant role in the pathogenesis, progression, and prognosis of cutaneous malignant melanoma (MM). Cutaneous melanoma is the most common skin cancer, with an incidence that rapidly increased in recent decades. Melanoma is a highly immunogenic tumor, due to its high mutational burden. The metastatic form retains a high mortality. The advent of immunotherapy revolutionized the therapeutic approach to this tumor and significantly ameliorated the patients' clinical outcome. In this review, we will recapitulate the multiple roles of innate immune cells in melanoma and the related implications for immunotherapy.

Monoclonal antibodies targeting interleukins for systemic lupus erythematosus: updates in early clinical drug development

INTRODUCTION

The advent of biological therapies has already revolutionized treatment strategies and disease course of several rheumatologic conditions, and monoclonal antibodies (mAbs) targeting cytokines and interleukins represent a considerable portion of this family of drugs. In systemic lupus erythematosus (SLE) dysregulation of different cytokine and interleukin-related pathways have been linked to disease development and perpetration, offering palatable therapeutic targets addressable via such mAbs.

AREAS COVERED

In this review, we provide an overview of the different biological therapies under development targeting cytokines and interleukins, with a focus on mAbs, while providing the rationale behind their choice as therapeutic targets and analyzing the scientific evidence linking them to SLE pathogenesis.

EXPERT OPINION

An unprecedented number of clinical trials on biological drugs targeting different immunological pathways are ongoing in SLE. Their success might allow us to tackle present challenges of SLE management, including the overuse of glucocorticoids in daily clinical practice, as well as SLE heterogenicity in treatment response among different individuals, hopefully paving the way toward precision medicine.

Past and present discovery of the BAFF/APRIL system - A bibliometric study from 1999 to 2023

Cytokines from the Tumour Necrosis Factor (TNF) family are important regulators of both physiological and pathological processes. The discovery of novel TNF ligands and receptors, BAFF and APRIL, have opened up new possibilities for scientists to explore the effect of these cytokines on the human immune system. The role of BAFF/APRIL system in B lymphocytes is particularly important for survival and maintenance of homeostasis. Aberrant expression of the system is associated with various immunological disorders. Hence, this study provides a comprehensive overview of the past and present BAFF/APRIL system research development in a bibliometric perspective. To our best knowledge, this is the first ever bibliometric analysis conducted focusing on the BAFF/APRIL system. A total of 1055 relevant documents were retrieved from WoSCC. Microsoft Excel, VOSviewer, and Biblioshiny of R studio were bibliometric tools used to analyse the scientific literature. From 1999, the annual publications showed an upward trend, with Journal of Immunology being the most productive journal. USA leads the race for BAFF/APRIL system research developments. Pascal Schneider, a senior researcher affiliated with University of Lausanne, Switzerland was recognised as the most productive author and institution in the BAFF/APRIL system research field. The research focus transitioned from focusing on the role of the system in B cell biology, to immunological disorders and finally to development of BAFF/APRIL targeting drugs. Despite several studies elucidating briefly the pathway mechanism of BAFF/APRIL system in B-cell selection, substantial research on the mechanism of action in disease models and T cell activation and development of immunomodulating drugs from natural origins remains largely unexplored. Therefore, future research focusing on these areas are crucial for the deeper understanding of the system in disease manifestations and progression allowing a better treatment management for various immunological disorders.

Unique and redundant roles of mouse BCMA, TACI, BAFF, APRIL, and IL-6 in supporting antibody-producing cells in different tissues

Antibody-producing plasma cells fuel humoral immune responses. They also contribute to autoimmune diseases such as systemic lupus erythematosus or IgA nephropathy. Interleukin-6 and the tumor necrosis factor (TNF) family ligands BAFF (B cell-activating factor) and APRIL (a proliferation-inducing ligand) participate in plasma cell survival. BAFF binds to three receptors, BAFFR (BAFF receptor), TACI (transmembrane activator and CAML interactor), and BCMA (B cell maturation antigen), while APRIL binds to TACI, BCMA, and proteoglycans. However, which ligand-receptor pair(s) are required to maintain plasma cells in different body locations remains unknown. Here, by combining mouse genetic and pharmacological approaches, we found that plasma cells required BCMA and/or TACI but not BAFFR. BCMA responded exclusively to APRIL, while TACI responded to both BAFF and APRIL, identifying three self-sufficient ligand-receptor pairs for plasma cell maintenance: BAFF-TACI, APRIL-TACI, and APRIL-BCMA. Together, these actors accounted for 90% of circulating antibodies. In BAFF-ko mice, the reduction of plasma cells upon APRIL inhibition indicated that APRIL could function in the absence of BAFF-APRIL heteromers. No evidence was found that in the absence of BCMA and TACI, binding of APRIL to proteoglycans would help maintain plasma cells. IL-6, alone or together with BAFF and APRIL, supported mainly splenic plasmablasts and plasma cells and contributed to circulating IgG but not IgA levels. In conclusion, survival factors for plasma cells can vary with body location and with the antibody isotype that plasma cells produce. To efficiently target plasma cells, in particular IgA-producing ones, dual inhibition of BAFF and APRIL is required.

Type I interferon induced during chronic viral infection favors B-cell development in the thymus

Chronic viral infections cause thymic involution yet the potential for broader, longer-term impact on thymic composition remains unexplored. Here we show that chronic, but not acute, lymphocytic choriomeningitis virus infection promotes a unique population of immature B cells in the thymus. We show that chronic viral infection promotes signals within the thymus, including the expression of B-cell activating factor (BAFF), that favor the maturation of this population as these cells acquire expression of CD19 and immunoglobulin M. Mechanistically, type I interferon (IFN-I), predominantly IFNβ, signals to thymic hematopoietic cells, strongly delaying T-cell development at the earliest precursor stage. Furthermore, IFN-I signaling to the nonhematopoietic compartment provides a second signal essential to favor B-cell differentiation and maturation within the thymus. Importantly, chronic infection yields changes in the B-cell population for at least 50 days following infection, long after thymic atrophy has subsided. Thus, the inflammatory milieu induced by chronic viral infection has a profound, and long-lasting, effect on thymic composition leading to the generation of a novel population of thymic B cells.

Unraveling the Immune Microenvironment in Diffuse Large B-Cell Lymphoma: Prognostic and Potential Therapeutic Implications

Diffuse large B cell lymphoma (DLBCL) is a multifaceted condition characterized by significant diversity in its molecular and pathological subtypes and clinical manifestation. Despite the progress made in the treatment of DLBCL through the development of novel drugs, an estimated one-third of patients encounter relapse or acquire refractory disease. The tumor microenvironment (TME) of DLBCL, a complex network consisting of cellular and noncellular components that engage in interactions with the tumor, is a parameter that is gaining increasing attention. The TME comprises both the immune and nonimmune microenvironments. The immune microenvironment comprises natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), neutrophils, myeloid-derived suppressor cells (MDSCs), and T and B lymphocytes. The nonimmune microenvironment consists of the extracellular matrix (ECM), cancer-associated fibroblasts (CAFs), mesenchymal stromal cells, and other molecules that are secreted. Despite ongoing research, the exact impact of these components and their interaction on the progression of the disease remains elusive. A comprehensive review of significant discoveries concerning the cellular and noncellular constituents, molecular characteristics, and treatment response and prognosis of the TME in DLBCL, as well as the potential targeting of the TME with novel therapeutic approaches, is provided in this article.

Unmasking the NLRP3 inflammasome in dendritic cells as a potential therapeutic target for autoimmunity, cancer, and infectious conditions

Proper and functional immune response requires a complex interaction between innate and adaptive immune cells, which dendritic cells (DCs) are the primary actors in this coordination as professional antigen-presenting cells. DCs are armed with numerous pattern recognition receptors (PRRs) such as nucleotide-binding and oligomerization domain-like receptors (NLRs) like NLRP3, which influence the development of their activation state upon sensation of ligands. NLRP3 is a crucial component of the immune system for protection against tumors and infectious agents, because its activation leads to the assembly of inflammasomes that cause the formation of active caspase-1 and stimulate the maturation and release of proinflammatory cytokines. But, when NLRP3 becomes overactivated, it plays a pathogenic role in the progression of several autoimmune disorders. So, NLRP3 activation is strictly regulated by diverse signaling pathways that are mentioned in detail in this review. Furthermore, the role of NLRP3 in all of the diverse immune cells' subsets is briefly mentioned in this study because NLRP3 plays a pivotal role in modulating other immune cells which are accompanied by DCs' responses and subsequently influence differentiation of T cells to diverse T helper subsets and even impact on cytotoxic CD8+ T cells' responses. This review sheds light on the functional and therapeutic role of NLRP3 in DCs and its contribution to the occurrence and progression of autoimmune disorders, prevention of diverse tumors' development, and recognition and annihilation of various infectious agents. Furthermore, we highlight NLRP3 targeting potential for improving DC-based immunotherapeutic approaches, to be used for the benefit of patients suffering from these disorders.

A Glimpse into Humoral Response and Related Therapeutic Approaches of Takayasu's Arteritis

Takayasu's arteritis (TAK) manifests as an insidiously progressive and debilitating form of granulomatous inflammation including the aorta and its major branches. The precise etiology of TAK remains elusive, with current understanding suggesting an autoimmune origin primarily driven by T cells. Notably, a growing body of evidence bears testimony to the widespread effects of B cells on disease pathogenesis and progression. Distinct alterations in peripheral B cell subsets have been described in individuals with TAK. Advancements in technology have facilitated the identification of novel autoantibodies in TAK. Moreover, emerging data suggest that dysregulated signaling cascades downstream of B cell receptor families, including interactions with innate pattern recognition receptors such as toll-like receptors, as well as co-stimulatory molecules like CD40, CD80 and CD86, may result in the selection and proliferation of autoreactive B cell clones in TAK. Additionally, ectopic lymphoid neogenesis within the aortic wall of TAK patients exhibits functional characteristics. In recent decades, therapeutic interventions targeting B cells, notably utilizing the anti-CD20 monoclonal antibody rituximab, have demonstrated efficacy in TAK. Despite the importance of the humoral immune response, a systematic understanding of how autoreactive B cells contribute to the pathogenic process is still lacking. This review provides a comprehensive overview of the biological significance of B cell-mediated autoimmunity in TAK pathogenesis, as well as insights into therapeutic strategies targeting the humoral response. Furthermore, it examines the roles of T-helper and T follicular helper cells in humoral immunity and their potential contributions to disease mechanisms. We believe that further identification of the pathogenic role of autoimmune B cells and the underlying regulation system will lead to deeper personalized management of TAK patients. We believe that further elucidation of the pathogenic role of autoimmune B cells and the underlying regulatory mechanisms holds promise for the development of personalized approaches to managing TAK patients.

The bidirectional relationship of depression and disturbances in B cell homeostasis: Double trouble

Major depressive disorder (MDD) is a recurrent, persistent, and debilitating neuropsychiatric syndrome with an increasing morbidity and mortality, representing the leading cause of disability worldwide. The dysregulation of immune systems (including innate and adaptive immune systems) has been identified as one of the key contributing factors in the progression of MDD. As the main force of the humoral immunity, B cells have an essential role in the defense against infections, antitumor immunity and autoimmune diseases. Several recent studies have suggested an intriguing connection between disturbances in B cell homeostasis and the pathogenesis of MDD, however, the B-cell-dependent mechanism of MDD remains largely unexplored compared to other immune cells. In this review, we provide an overview of how B cell abnormality regulates the progression of MMD and the potential consequence of the disruption of B cell homeostasis in patients with MDD. Abnormalities of B-cell homeostasis not only promote susceptibility to MDD, but also lead to an increased risk of developing infection, malignancy and autoimmune diseases in patients with MDD. A better understanding of the contribution of B cells underlying MDD would provide opportunities for identification of more targeted treatment approaches and might provide an overall therapeutic benefit to improve the long-term outcomes of patients with MDD.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Assessment of Corneal Epithelial Changes and Related Factors in Ocular Chronic Graft-Versus-Host Disease (GVHD) by in Vivo Confocal Microscopy

PURPOSE

To evaluate corneal epithelial changes and related factors in chronic ocular graft-versus-host disease (oGVHD) patients.

METHODS

21 patients (35 eyes) with chronic oGVHD and 8 patients (12 eyes) without oGVHD after bone marrow transplantation were recruited for assessment involving in vivo confocal microscopy (IVCM) analysis, ocular surface parameter determination and tear cytokine level analysis. The IVCM corneal epithelial scoring system was used to evaluate corneal epithelial changes.

RESULTS

There was a significant difference in the corneal epithelial score (p = .001) between the two groups. The corneal epithelial scores were significantly correlated with the corneal fluorescein staining scores (CFS, r = 0.463, p < .001), Schirmer's test (r = -0.389, p = .009) and tear cytokine levels of EGF (r = -0.491, p < .001) and APRIL (r = -0.318, p = .030).

CONCLUSIONS

The depth of corneal epithelial defects can be estimated by the CFS. Corneal epithelial changes of chronic oGVHD are considered to be associated with lacrimal deficiency and a lack of EGF.

B cell depletion with anti-CD20 promotes neuroprotection in a BAFF-dependent manner in mice and humans

Anti-CD20 therapy to deplete B cells is highly efficacious in preventing new white matter lesions in patients with relapsing-remitting multiple sclerosis (RRMS), but its protective capacity against gray matter injury and axonal damage is unclear. In a passive experimental autoimmune encephalomyelitis (EAE) model whereby TH17 cells promote brain leptomeningeal immune cell aggregates, we found that anti-CD20 treatment effectively spared myelin content and prevented myeloid cell activation, oxidative damage, and mitochondrial stress in the subpial gray matter. Anti-CD20 treatment increased B cell survival factor (BAFF) in the serum, cerebrospinal fluid, and leptomeninges of mice with EAE. Although anti-CD20 prevented gray matter demyelination, axonal loss, and neuronal atrophy, co-treatment with anti-BAFF abrogated these benefits. Consistent with the murine studies, we observed that elevated BAFF concentrations after anti-CD20 treatment in patients with RRMS were associated with better clinical outcomes. Moreover, BAFF promoted survival of human neurons in vitro. Together, our data demonstrate that BAFF exerts beneficial functions in MS and EAE in the context of anti-CD20 treatment.

The tri-flow adaptiveness of codes in major evolutionary transitions

Life codes increase in both number and variety with biological complexity. Although our knowledge of codes is constantly expanding, the evolutionary progression of organic, neural, and cultural codes in response to selection pressure remains poorly understood. Greater clarification of the selective mechanisms is achieved by investigating how major evolutionary transitions reduce spatiotemporal and energetic constraints on transmitting heritable code to offspring. Evolution toward less constrained flows is integral to enduring flow architecture everywhere, in both engineered and natural flow systems. Beginning approximately 4 billion years ago, the most basic level for transmitting genetic material to offspring was initiated by protocell division. Evidence from ribosomes suggests that protocells transmitted comma-free or circular codes, preceding the evolution of standard genetic code. This rudimentary information flow within protocells is likely to have first emerged within the geo-energetic and geospatial constraints of hydrothermal vents. A broad-gauged hypothesis is that major evolutionary transitions overcame such constraints with tri-flow adaptations. The interconnected triple flows incorporated energy-converting, spatiotemporal, and code-based informational dynamics. Such tri-flow adaptations stacked sequence splicing code on top of protein-DNA recognition code in eukaryotes, prefiguring the transition to sexual reproduction. Sex overcame the spatiotemporal-energetic constraints of binary fission with further code stacking. Examples are tubulin code and transcription initiation code in vertebrates. In a later evolutionary transition, language reduced metabolic-spatiotemporal constraints on inheritance by stacking phonetic, phonological, and orthographic codes. In organisms that reproduce sexually, each major evolutionary transition is shown to be a tri-flow adaptation that adds new levels of code-based informational exchange. Evolving biological complexity is also shown to increase the nongenetic transmissibility of code.

An unappreciated cell survival-independent role for BAFF initiating chronic lymphocytic leukemia

Background

Chronic Lymphocytic Leukemia (CLL) is characterized by the expansion of CD19+ CD5+ B cells but its origin remains debated. Mutated CLL may originate from post-germinal center B cells and unmutated CLL from CD5+ mature B cell precursors. Irrespective of precursor types, events initiating CLL remain unknown. The cytokines BAFF and APRIL each play a significant role in CLL cell survival and accumulation, but their involvement in disease initiation remains unclear.

Methods

We generated novel CLL models lacking BAFF or APRIL. In vivo experiments were conducted to explore the impact of BAFF or APRIL loss on leukemia initiation, progression, and dissemination. Additionally, RNA-seq and quantitative real-time PCR were performed to unveil the transcriptomic signature influenced by BAFF in CLL. The direct role of BAFF in controlling the expression of tumor-promoting genes was further assessed in patient-derived primary CLL cells ex-vivo.

Results

Our findings demonstrate a crucial role for BAFF, but not APRIL, in the initiation and dissemination of CLL cells. In the absence of BAFF or its receptor BAFF-R, the TCL1 transgene only increases CLL cell numbers in the peritoneal cavity, without dissemination into the periphery. While BAFF binding to BAFF-R is dispensable for peritoneal CLL cell survival, it is necessary to activate a tumor-promoting gene program, potentially linked to CLL initiation and progression. This direct role of BAFF in controlling the expression of tumor-promoting genes was confirmed in patient-derived primary CLL cells ex-vivo.

Conclusions

Our study, involving both mouse and human CLL cells, suggests that BAFF might initiate CLL through mechanisms independent of cell survival. Combining current CLL therapies with BAFF inhibition could offer a dual benefit by reducing peripheral tumor burden and suppressing transformed CLL cell output.

New blood biomarkers and imaging for disease stratification and monitoring of giant cell arteritis

Relapses and late complications remain a concern in giant cell arteritis (GCA). Monitoring strategies are required to effectively tailor treatment and improve patients' outcomes. Current monitoring of GCA is based on clinical assessment and evaluation of traditional inflammatory markers such as C reactive protein and erythrocyte sedimentation rate; however, this approach has limited value in patients receiving interleukin (IL)-6 blocking agents. New blood biomarkers that are less dependent on the IL-6 axis such as IL-23, B cell activating factor, osteopontin and calprotectin have been explored, but none of them has yet accumulated sufficient evidence to qualify as a routine follow-up parameter. Imaging techniques, including ultrasound and 18F-fluorodeoxyglucose positron emission tomography/computed tomography, potentially offer additional insights; however, the choice of the imaging method as well as its interpretation must be investigated further. Future studies are required to investigate the outcome of patients with GCA whose treatment decisions are based on traditional plus novel (laboratory and imaging) biomarkers as compared with those undergoing conventional monitoring strategies.

Unraveling the Role of the NLRP3 Inflammasome in Lymphoma: Implications in Pathogenesis and Therapeutic Strategies

Inflammasomes are multimeric protein complexes, sensors of intracellular danger signals, and crucial components of the innate immune system, with the NLRP3 inflammasome being the best characterized among them. The increasing scientific interest in the mechanisms interconnecting inflammation and tumorigenesis has led to the study of the NLRP3 inflammasome in the setting of various neoplasms. Despite a plethora of data regarding solid tumors, NLRP3 inflammasome's implication in the pathogenesis of hematological malignancies only recently gained attention. In this review, we investigate its role in normal lymphopoiesis and lymphomagenesis. Considering that lymphomas comprise a heterogeneous group of hematologic neoplasms, both tumor-promoting and tumor-suppressing properties were attributed to the NLRP3 inflammasome, affecting neoplastic cells and immune cells in the tumor microenvironment. NLRP3 inflammasome-related proteins were associated with disease characteristics, response to treatment, and prognosis. Few studies assess the efficacy of NLRP3 inflammasome therapeutic targeting with encouraging results, though most are still at the preclinical level. Further understanding of the mechanisms regulating NLRP3 inflammasome activation during lymphoma development and progression can contribute to the investigation of novel treatment approaches to cover unmet needs in lymphoma therapeutics.

The role of BAFF and APRIL in IgA nephropathy: pathogenic mechanisms and targeted therapies

Immunoglobulin A nephropathy (IgAN), characterized by mesangial deposition of galactose-deficient-IgA1 (Gd-IgA1), is the most common biopsy-proven primary glomerulonephritis worldwide. Recently, an improved understanding of its underlying pathogenesis and the substantial risk of progression to kidney failure has emerged. The "four-hit hypothesis" of IgAN pathogenesis outlines a process that begins with elevated circulating levels of Gd-IgA1 that trigger autoantibody production. This results in the formation and deposition of immune complexes in the mesangium, leading to inflammation and kidney injury. Key mediators of the production of Gd-IgA1 and its corresponding autoantibodies are B-cell activating factor (BAFF), and A proliferation-inducing ligand (APRIL), each playing essential roles in the survival and maintenance of B cells and humoral immunity. Elevated serum levels of both BAFF and APRIL are observed in patients with IgAN and correlate with disease severity. This review explores the complex pathogenesis of IgAN, highlighting the pivotal roles of BAFF and APRIL in the interplay between mucosal hyper-responsiveness, B-cell activation, and the consequent overproduction of Gd-IgA1 and its autoantibodies that are key features in this disease. Finally, the potential therapeutic benefits of inhibiting BAFF and APRIL in IgAN, and a summary of recent clinical trial data, will be discussed.

Analytical assessment and validation of the ProteinSimple ELLA serum B-cell maturation antigen assay

Objectives

Soluble B-Cell Maturation Antigen (sBCMA) is a degradation product of plasma cell-bound BCMA found in serum. Serum sBCMA concentrations correlate with bone marrow plasma cellularity, making it an attractive biomarker for monitoring plasma cell disorders, such as multiple myeloma. Here we evaluated the automated BCMA immunoassay for the ProteinSimple ELLA, for the analysis of sBCMA.

Design & methods

Inter and intra-run precision was assessed through replicate sBCMA measurements at 3 different concentration levels. Linearity was determined through serial dilution of a high sBMCA patient sample. Accuracy was assessed through split specimen analysis on two separate lots of reagents. Stability was assessed at 3 temperature levels over 14 days. Cross-reactivity was assessed on BCMA targeting and non-targeting chemotherapeutics. A reference range was established through the analysis of 146 healthy donor samples. The effect of endogenous interferents was assessed through spiking and recovery studies.

Results

Inter and intra-run precision studies afforded CVs of <10% at all three concentration levels. Analytical measurement range was confirmed from 0.1 to 7 ng/mL. Accuracy studies afforded a slope of 0.976, intercept of 1.22, R2 of 0.996. Assayed sBCMA values were unaffected by endogenous interferents and non-BMCA targeting antibodies. BCMA targeting therapeutics negatively affected assayed sBCMA concentrations. The reference range was established at 19-58 ng/mL sBCMA is analytically stable.

Conclusions

The ProteinSimple ELLA sBCMA assay shows acceptable performance for the clinical assessment of sBCMA. The assay was highly affected by BCMA targeting therapeutics, thereby patients undergoing this therapy should not have their sBCMA levels assessed by this method.

Therapeutic tactics for targeting B lymphocytes in autoimmunity and cancer

B lymphocytes have become a very popular therapeutic target in a number of autoimmune indications due to their newly appreciated roles, and approachability, in these diseases. Many of the therapies now applied in autoimmunity were initially developed to deplete malignant B cells. These strategies have also been found to benefit patients suffering from such autoimmune diseases as multiple sclerosis, type I diabetes, systemic lupus erythematosus, and rheumatoid arthritis, to name a few. These observations have supported the expansion of research addressing the mechanistic contributions of B cells in these diseases, as well as blossoming of therapeutics that target them. This review seeks to summarize cutting-edge modalities for targeting B cells, including monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, chimeric antigen receptor-T cells, and small molecule inhibitors. Efforts to refine B-cell targeted therapy to eliminate only pathogenic autoreactive cells will be addressed as well as the potential for future B-cell-based cellular therapeutics. Finally, we also address approaches that seek to silence B-cell function without depletion.

B cell activating factor levels are linked to distinct B cell markers in multiple sclerosis and following B cell depletion and repopulation

Recent studies have highlighted the important role of B cells in the pathogenesis of multiple sclerosis (MS). B cell activating factor (BAFF) and A proliferation inducing ligand (APRIL) play a major role in B cell survival and homeostasis. Here, we studied the association of BAFF and APRIL with B cell immune markers in MS and following B cell depletion and repopulation. We found that BAFF but not APRIL was significantly higher in plasma in untreated MS compared to controls. BAFF increased after rituximab treatment and decreased again during repopulation displaying an inverse correlation with B cell numbers, and more specifically switched memory B cell numbers. Cerebrospinal fluid BAFF inversely correlated with IgG index. BAFF displayed an inverse association to anti-EBV-CA antibodies. In summary, our study identified immune cells and factors that might regulate or be regulated by BAFF and APRIL levels in MS, and during B cell depletion and repopulation.

B-cell-activating factor (BAFF) and platelet-activating factor (PAF) in pregnancies complicated by maternal obesity and diabetes: a preliminary study

OBJECTIVE

In pregnancies complicated by maternal obesity and diabetes, a disruption in inflammatory mediators occurs, resulting in endothelial microvascular dysfunction, oxidative stress, tissue damage, and maternal and feto-neonatal complications. To outline this proinflammatory status, an innovative approach is represented by the measurement of proinflammatory cytokines. Among these biomarkers, B-cell-activating factor (BAFF) and platelet-activating factor (PAF) play a key role in metabolic regulation, immune response to infections, tissue homeostasis, and "food-related inflammation." The aim of the present study is to investigate the blood expression of BAFF and PAF in a cohort of pregnant women affected by obesity and diabetes compared with a control group of healthy pregnant women.

METHODS

A prospective longitudinal cohort study has been conducted on pregnant women referred to Fondazione Policlinico Universitario Gemelli IRCCS in Rome. For each pregnant woman, a capillary sample was collected with a swab in three different consecutive evaluations carried out in the three trimesters of pregnancy.

RESULTS

A total of 77 pregnant women have been enrolled. No significant differences in BAFF and PAF levels were longitudinally observed between groups. Focusing on the exposed group, in the third trimester of pregnancy, both PAF and BAFF levels were lower than the basal time. Among the selected group of patients who developed Gestational Diabetes, only PAF values were longitudinally lower when compared to other groups. The multivariate analysis showed that BAFF levels were positively correlated with thyroid-stimulating hormone levels. No macrosomia, no shoulder dystocia, no major perineal lacerations at birth, and no intrauterine growth restriction were observed in the whole population.

CONCLUSIONS

This study supports the involvement of metabolic and proinflammatory biomarkers in the mechanisms related to pregnancy complications. Improving a good metabolic environment for obese and diabetic pregnant women could break the vicious cycle connecting inflammation, oxidative stress, and metabolic disorders.

Translational implications of newly characterized pathogenic pathways in systemic lupus erythematosus

Improved characterization of relevant pathogenic pathways in systemic lupus erythematosus (SLE) has been further delineated over the last decades. This led to the development of targeted treatments including belimumab and anifrolumab, which recently became available in clinics. Therapeutic targets in SLE encompass interferon (IFN) signaling, B-T costimulation including immune checkpoints, and increasing modalities of B lineage targeting, such as chimeric antigen receptor (CAR) T cells directed against CD19 or sequential anti-B cell targeting. Patient profiling based on characterization of underlying molecular abnormalities, often performed through comprehensive omics analyses, has recently been shown to better predict patients' treatment responses and also holds promise to unravel key molecular mechanisms driving SLE. SLE carries two key signatures, namely the IFN and B lineage/plasma cell signatures. Recent advances in SLE treatments clearly indicate that targeting innate and adaptive immunity is successful in such a complex autoimmune disease. Although those signatures may interact at the molecular level and provide the basis for the first selective treatments in SLE, it remains to be clarified whether these distinct treatments show different treatment responses among certain patient subsets. In fact, notwithstanding the remarkable amount of novel clues for innovative SLE treatment, harmonization of big data within tailored treatment strategies will be instrumental to better understand and treat this challenging autoimmune disorder. This review will provide an overview of recent improvements in SLE pathogenesis, related insights by analyses of big data and machine learning as well as technical improvements in conducting clinical trials with the ultimate goal that translational research results in improved patient outcomes.

Inflammasomes cross-talk with lymphocytes to connect the innate and adaptive immune response

BACKGROUND

Innate and adaptive immunity are two different parts of the immune system that have different characteristics and work together to provide immune protection. Inflammasomes are a major part of the innate immune system that are expressed widely in myeloid cells and are responsible for inflammatory responses. Recent studies have shown that inflammasomes are also expressed and activated in lymphocytes, especially in T and B cells, to regulate the adaptive immune response. Activation of inflammasomes is also under the control of lymphocytes. Therefore, we propose that inflammasomes act as a bridge and they provide crosstalk between the innate and adaptive immune systems to obtain a fine balance in immune responses.

AIM OF REVIEW

This review systematially summarizes the interaction between inflammasomes and lymphocytes and describes the crosstalk between the innate and adaptive immune systems induced by inflammasomes, with the aim of providing new directions and important areas for further research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

When considering the novel function of inflammasomes in various lymphocytes, attention should be given to the activity of specific inflammasomes in studies of lymphocyte function. Moreover, research on the function of various inflammasomes in lymphocytes will help advance knowledge on the mechanisms and treatment of various diseases, including autoimmune diseases and tumors. In addition, when studying inflammatory responses, inflammasomes in both lymphocytes and myeloid cells need to be considered.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

Readministration of high-dose adeno-associated virus gene therapy vectors enabled by ImmTOR nanoparticles combined with B cell-targeted agents

Tolerogenic ImmTOR nanoparticles encapsulating rapamycin have been demonstrated to mitigate immunogenicity of adeno-associated virus (AAV) gene therapy vectors, enhance levels of transgene expression, and enable redosing of AAV at moderate vector doses of 2 to 5E12 vg/kg. However, recent clinical trials have often pushed AAV vector doses 10-fold to 50-fold higher, with serious adverse events observed at the upper range. Here, we assessed combination therapy of ImmTOR with B cell-targeting drugs for the ability to increase the efficiency of redosing at high vector doses. The combination of ImmTOR with a monoclonal antibody against B cell activation factor (aBAFF) exhibited strong synergy leading to more than a 5-fold to 10-fold reduction of splenic mature B cells and plasmablasts while increasing the fraction of pre-/pro-B cells. In addition, this combination dramatically reduced anti-AAV IgM and IgG antibodies, thus enabling four successive AAV administrations at doses up to 5E12 vg/kg and at least two AAV doses at 5E13 vg/kg, with the transgene expression level in the latter case being equal to that observed in control animals receiving a single vector dose of 1E14 vg/kg. Similar synergistic effects were seen with a combination of ImmTOR and a Bruton's tyrosine kinase inhibitor, ibrutinib. These results suggest that ImmTOR could be combined with B cell-targeting agents to enable repeated vector administrations as a potential strategy to avoid toxicities associated with vector doses above 1E14 vg/kg.

Bidirectional crosstalk between therapeutic cancer vaccines and the tumor microenvironment: Beyond tumor antigens

Immunotherapy has rejuvenated cancer therapy, especially after anti-PD-(L)1 came onto the scene. Among the many therapeutic options, therapeutic cancer vaccines are one of the most essential players. Although great progress has been made in research on tumor antigen vaccines, few phase III trials have shown clinical benefits. One of the reasons lies in obstruction from the tumor microenvironment (TME). Meanwhile, the therapeutic cancer vaccine reshapes the TME in an ambivalent way, leading to immune stimulation or immune escape. In this review, we summarize recent progress on the interaction between therapeutic cancer vaccines and the TME. With respect to vaccine resistance, innate immunosuppressive TME components and acquired resistance caused by vaccination are both involved. Understanding the underlying mechanism of this crosstalk provides insight into the treatment of cancer by directly targeting the TME or synergizing with other therapeutics.

Efficacy and safety of novel biologics in the treatment of lupus nephritis based on registered clinical trials: a systematic review and network meta-analysis

To compare the clinical effectiveness and safety of novel biologics for the treatment of lupus nephritis based on a reticulated meta-analysis approach. Registered clinical trials in 4 major databases (PubMed, Embase, Web of Science, The Cochrane Register of Clinical Trials) and ClinicalTrials.gov were systematically searched with a search time frame of build to June 2022. And we screened registered randomized controlled clinical trials of biologics for the treatment of lupus nephritis according to the protocol's nadir criteria. Trials were evaluated for quality using the Cochrane Risk of Bias Assessment Tool, and data were statistically analyzed using Stata 16.0 and Review Manager 5.3 software to compare and rank differences in effectiveness and safety between the biologics. A total of 10 registered randomized controlled clinical trials involving 2148 subjects were included in this study. The interventions were ranked from best to worst in terms of the primary outcome indicator of effectiveness, renal complete remission: belimumab > anifrolumab (900 + 300) mg > obinutuzumab > ocrelizumab 400 mg > abatacept 30/10 mg/kg > belimumab + rituximab > abatacept 10/10 mg/kg > abatacept (30/10 + 10/10) mg/kg > placeo > ocrelizumab 1000 mg > rituximab > anifrolumab 300 mg, belimumab was superior to placebo [OR = 1.75, 95% CI (1.13, 2.70)] and anifrolumab 300 mg [OR = 3.27, 95% CI (1.05, 10.14)], anifrolumab (900 + 300) mg was superior to anifrolumab 300 mg [OR = 3.56, 95% CI (1.30, 9.76)], and all were statistically significant. The ranking of each intervention in terms of overall renal remission for secondary outcome indicators from best to worst was: obinutuzumab > belimumab + rituximab > anifrolumab (900 + 300) mg > ocrelizumab 1000 mg > ocrelizumab 400 mg > belimumab > rituximab 1000 mg > abatacept 30/10 mg/kg > abatacept (30/10 + 10/10) mg/kg > placeo > abatacept 10/10 mg/kg > anifrolumab 300 mg, obinutuzumab was superior to placebo [OR = 2.27, 95% CI (1.11, 4.67)] and belimumab was also superior to placebo [OR = 1.56, 95% CI (1.07, 2.27)], and all were statistically significant. In terms of safety, with a focus on serious adverse events and serious infections, the results were: Serious adverse events at 1 year of monitoring occurred better with ocrelizumab 1000 mg than ocrelizumab 400 mg [OR = 0.51, 95% CI (0.29, 0.89)] and were statistically different; serious adverse events at 2 years of monitoring infection adverse events occurred better with obinutuzumab than with abatacept (30/10 + 10/10) mg/kg [OR = 0.24, 95% CI (0.07, 0.81)] and were statistically different. The safety of the new biologics in combination with conventional standard therapies is generally good, but it is belimumab and obinutuzumab that are most effective in achieving complete and overall remission in the kidney. This study protocol has been registered with PROSPERO, with a registration number of CRD42021262498.

From systemic lupus erythematosus to lupus nephritis: The evolving road to targeted therapies

Systemic lupus erythematosus is a chronic autoimmune disease characterized by loss of tolerance against nuclear and cytoplasmic self-antigens, induction of immunity and tissue inflammation. Lupus nephritis (LN), the most important predictor of morbidity in SLE, develops in almost 30% of SLE patients at disease onset and in up to 50-60% within the first 10 years. Firstly, in this review, we put the pathogenic mechanisms of the disease into a conceptual frame, giving emphasis to the role of the innate immune system in this loss of self-tolerance and the induction of the adaptive immune response. In this aspect, many mechanisms have been described such as dysregulation and acceleration of cell-death pathways, an aberrant clearance and overload of immunogenic acid-nucleic-containing debris and IC, and the involvement of antigen-presenting cells and other innate immune cells in the induction of this adaptive immune response. This result in a clonal expansion of autoreactive lymphocytes with generation of effector T-cells, memory B-cells and plasma cells that produce autoantibodies that will cause kidney damage. Secondly, we review the immunological pathways of damage in the kidney parenchyma, initiated by autoantibody binding and immune complex deposition, and followed by complement-mediated microvascular injury, activation of kidney stromal cells and the recruitment of leukocytes. Finally, we summarize the rationale for the treatment of LN, from conventional to new targeted therapies, focusing on their systemic immunologic effects and the minimization of podocytary damage.

Skeletal muscle fibers produce B-cell stimulatory factors in chronic myositis

Introduction

We aimed to identify B-cell-mediated immunomechanisms in inclusion body myositis (IBM) and polymyositis (PM) as part of the complex pathophysiology.

Materials and methods

Human primary myotube cultures were derived from orthopedic surgery. Diagnostic biopsy specimens from patients with IBM (n=9) and PM (n=9) were analyzed for markers of B cell activation (BAFF and APRIL) and for chemokines that control the recruitment of B cells (CXCL-12 and CXCL-13). Results were compared to biopsy specimens without myopathic changes (n=9) and hereditary muscular dystrophy (n=9).

Results

The mRNA expression of BAFF, APRIL, and CXCL-13 was significantly higher in IBM and PM compared to controls. Patients with IBM displayed the highest number of double positive muscle fibers for BAFF and CXCL-12 (48%) compared to PM (25%), muscular dystrophy (3%), and non-myopathic controls (0%). In vitro, exposure of human myotubes to pro-inflammatory cytokines led to a significant upregulation of BAFF and CXCL-12, but APRIL and CXCL-13 remained unchanged.

Conclusion

The results substantiate the hypothesis of an involvement of B cell-associated mechanisms in the pathophysiology of IBM and PM. Muscle fibers themselves seem to contribute to the recruitment of B cells and sustain inflammation.

Physiological Changes in the Levels of Anti-Cytokine Autoantibodies in Early Pregnancy Are Missing in Pregnant Women with Hashimoto's Thyroiditis

T helper type 1 (Th1) and inflammatory cytokines play essential roles in early pregnancy and also in the pathogenesis of Hashimoto's thyroiditis (HT). Changes in the serum level of autoantibodies to cytokines, which may be able to modulate their availability and actions have been described in several autoimmune disorders. Yet, no data are available on anti-cytokine autoantibodies either during early pregnancy or in patients with HT. The aim of the study was to measure autoantibodies to inflammatory-, Th1- and Th22-cytokines in serum samples in healthy pregnancy (HP) and in pregnant women with HT (HTP). As pathological autoantibodies are hallmarks of HT, in addition we also measured anti-B-cell activator factor (BAFF) autoantibodies. The measurement was carried out with a Luminex multiplex assay and the Luminex MAGPIX Instrument, age-matched healthy women (HC) and women with HT (HT) were used as controls. In the first trimester of HP, anti-TNFα, anti-IL-8, and anti-IFNγ autoantibodies were significantly decreased, while autoantibodies to BAFF were significantly elevated compared to the HC. However, these alterations were not present in the HTP. Moreover, the levels of autoantibodies to IL-22 and TNFα were significantly increased in HTP compared to the HP. All differences in the levels of the investigated autoantibodies could be detected in the first trimester of pregnancies except for anti-IL-22 autoantibodies. According to our results we can conclude that alterations in the levels of autoantibodies to inflammatory and Th1 cytokines are physiological in the first trimester of pregnancy and their disturbance can be associated with autoimmune conditions such as HT.

BAFF system expression in double negative 2, activated naïve and activated memory B cells in systemic lupus erythematosus

Introduction

B cell activating factor (BAFF) has an important role in normal B cell development. The aberrant expression of BAFF is related with the autoimmune diseases development like Systemic Lupus Erythematosus (SLE) for promoting self-reactive B cells survival. BAFF functions are exerted through its receptors BAFF-R (BR3), transmembrane activator calcium modulator and cyclophilin ligand interactor (TACI) and B cell maturation antigen (BCMA) that are reported to have differential expression on B cells in SLE. Recently, atypical B cells that express CD11c have been associated with SLE because they are prone to develop into antibody-secreting cells, however the relationship with BAFF remains unclear. This study aims to analyze the BAFF system expression on CXCR5- CD11c+ atypical B cell subsets double negative 2 (DN2), activated naïve (aNAV), switched memory (SWM) and unswitched memory (USM) B cells.

Methods

Forty-five SLE patients and 15 healthy subjects (HS) were included. Flow cytometry was used to evaluate the expression of the receptors in the B cell subpopulations. Enzyme-linked immunosorbent assay (ELISA) was performed to quantify the soluble levels of BAFF (sBAFF) and IL-21.

Results

We found increased frequency of CXCR5- CD11c+ atypical B cell subpopulations DN2, aNAV, SWM and USM B cells in SLE patients compared to HS. SLE patients had increased expression of membrane BAFF (mBAFF) and BCMA receptor in classic B cell subsets (DN, NAV, SWM and USM). Also, the CXCR5+ CD11c- DN1, resting naïve (rNAV), SWM and USM B cell subsets showed higher mBAFF expression in SLE. CXCR5- CD11c+ atypical B cell subpopulations DN2, SWM and USM B cells showed strong correlations with the expression of BAFF receptors. The atypical B cells DN2 in SLE showed significant decreased expression of TACI, which correlated with higher IL-21 levels. Also, lower expression of TACI in atypical B cell DN2 was associated with high disease activity.

Discussion

These results suggest a participation of the BAFF system in CXCR5- CD11c+ atypical B cell subsets in SLE patients. Decreased TACI expression on atypical B cells DN2 correlated with high disease activity in SLE patients supporting the immunoregulatory role of TACI in autoimmunity.

SJÖGREN SENDROMU İLE BAZI GEN POLİMORFİZMLERİ ARASINDAKİ OLASI BAĞLANTILAR

Objective: Sjögren’s syndrome is a complex and widespread autoimmune disease whose pathogenesis is not fully elucidated and environmental and genetic factors affect the development of the disease. In order to reveal the effect of genetic contribution, studies have been conducted on the genes previously shown to play a role in other autoimmune diseases such as systemic lupus erythromatosus. In addition, two GWAS studies were conducted to investigate the role of more genes in the disease by screening the entire genome and the relationship of previously unknown genes with SS was shown. Result and Discussion: Studies are being conducted with spontaneous and genetically modified animal models in order to better reveal the relationship between SS and genes and to reinforce the data obtained from humans. In this study, the relationship between the genes previously studied in other autoimmune diseases and the genes associated with SS in GWAS studies and the possible pathways that may contribute to the pathogenesis of the disease through related genes were investigated.

Post-transcriptional checkpoints in autoimmunity

Post-transcriptional regulation is a fundamental process in gene expression that has a role in diverse cellular processes, including immune responses. A core concept underlying post-transcriptional regulation is that protein abundance is not solely determined by transcript abundance. Indeed, transcription and translation are not directly coupled, and intervening steps occur between these processes, including the regulation of mRNA stability, localization and alternative splicing, which can impact protein abundance. These steps are controlled by various post-transcription factors such as RNA-binding proteins and non-coding RNAs, including microRNAs, and aberrant post-transcriptional regulation has been implicated in various pathological conditions. Indeed, studies on the pathogenesis of autoimmune and inflammatory diseases have identified various post-transcription factors as important regulators of immune cell-mediated and target effector cell-mediated pathological conditions. This Review summarizes current knowledge regarding the roles of post-transcriptional checkpoints in autoimmunity, as evidenced by studies in both haematopoietic and non-haematopoietic cells, and discusses the relevance of these findings for developing new anti-inflammatory therapies.

Features of BAFF and APRIL receptors on circulating B cells in antineutrophil cytoplasmic antibody-associated vasculitis

To investigate the features of circulating B cells, their expressing receptors, serum levels of B-cell activation factor of the TNF family (BAFF), and a proliferation-inducing ligand (APRIL) in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Blood samples from 24 patients with active AAV (a-AAV), 13 with inactive AAV (i-AAV), and 19 healthy controls (HC) were included in this study. The proportion of B cells and their expressing BAFF receptor (BAFF-R), transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), and B-cell maturation antigen were analyzed via flow cytometry. Serum levels of BAFF, APRIL, and interleukin (IL)-4, IL-6, IL-10, and IL-13 were also evaluated using an enzyme-linked immunosorbent assay. The proportion of plasmablasts (PB)/plasma cells (PC) and serum levels of BAFF, APRIL, IL-4, and IL-6 were significantly higher in a-AAV than in HC. Higher serum levels of BAFF, APRIL, and IL-4 were observed in i-AAV than in HC. Lower expression of BAFF-R on memory B cells and higher expression of TACI on CD19+ cells, immature B cells, and PB/PC were demonstrated in a-AAV and i-AAV than in HC. The population of memory B cells was positively associated with serum APRIL levels and BAFF-R expression in a-AAV. In conclusion, decreased expression of BAFF-R on memory B cells and increased expression of TACI on CD19+ cells, immature B cells, and PB/PC, as well as increased serum levels of BAFF and APRIL, were sustained even in the remission phase of AAV. Persistent aberrant signaling of BAFF/APRIL may contribute to disease relapse.

B cell abnormalities and autoantibody production in patients with partial RAG deficiency

Mutations in the recombination activating gene 1 (RAG1) and RAG2 in humans are associated with a broad spectrum of clinical phenotypes, from severe combined immunodeficiency to immune dysregulation. Partial (hypomorphic) RAG deficiency (pRD) in particular, frequently leads to hyperinflammation and autoimmunity, with several underlying intrinsic and extrinsic mechanisms causing a break in tolerance centrally and peripherally during T and B cell development. However, the relative contributions of these processes to immune dysregulation remain unclear. In this review, we specifically focus on the recently described tolerance break and B cell abnormalities, as well as consequent molecular and cellular mechanisms of autoantibody production in patients with pRD.

Early Cytomegalovirus Reactivation in Renal Recipients Is Associated with High Levels of B Cell Maturation Antigen Transcript Expression Prior to Transplantation

Cytomegalovirus (CMV) infection is the most frequent infection episode in kidney transplant (KT) recipients. Reactivation usually occurs in the first three months after transplantation and is associated with higher cellular and/or antibody-mediated rejection rates and poorer graft performance. CMV induces the expression of BAFF (B-cell-activating factor, a cytokine involved in the homeostasis of B cells), which communicates signals for survival and growth to B cells and virus-specific plasma cells via the R-BAFF (BAFF receptor), TACI (the calcium modulator, the cyclophilin ligand interactor), and BCMA (B cell maturation antigen) receptors. These molecules of the BAFF system have also been suggested as biomarkers for the development of alloantibodies and graft dysfunction. This prospective study included 30 CMV-IgG seropositive KT recipients. The expression levels of the genes BAFF-R, transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA) in peripheral blood leukocytes (PBL) pre-KT were determined using qPCR. qPCR was also used to monitor CMV reactivation in the first three months following KT. The remainder of the KT recipients were classified as CMV- reactivation, and those with more than 500 copies/mL in at least one sample were classified as CMV+ reactivation. There were no discernible variations in the BAFF-R and TACI transcript expression levels. In the CMV+ group, we examined the relationship between the transcript levels and peak viremia. Peak viremia levels and BCMA transcript levels showed a strong correlation. BAFF-R and TACI expressions showed no measurable differences. In patients with early CMV reactivation, high BCMA receptor expression was associated with increased plasmablast, lymphocyte B cell class-switched levels (LBCS), and viral load. Our findings demonstrate that pre-KT BCMA transcript levels increased in KT recipients with early CMV reactivation. These transcript levels positively correlate with peak viremia and weakly with plasmablast and LBCS levels in PBLs.

B cell-specific knockout of AID protects against atherosclerosis

Antigen-naive IgM-producing B cells are atheroprotective, whereas mature B cells producing class-switched antibodies promote atherosclerosis. Activation-induced cytidine deaminase (AID), which mediates class switch recombination (CSR), would thus be expected to foster atherosclerosis. Yet, AID also plays a major role in the establishment of B cell tolerance. We sought to define whether AID affects atherosclerotic plaque formation. We generated Ldlr^-/- chimeras transplanted with bone marrow from Aicda^-/- or wild-type (WT) mice, fed a HFD for 14 weeks. Decreased B cell maturation in Ldlr^-/-Aicda^-/- mice was demonstrated by 50% reduction in splenic and aortic BAFFR expression, a key signaling component of B2 cell maturation. This was associated with increased plasma IgM in Ldlr^-/-Aicda^-/- compared with Ldlr^-/-WT animals. Importantly, Ldlr^-/-Aicda^-/- mice had reduced atherosclerotic lesion area (0.20 ± 0.03mm²) compared with Ldlr^-/-WT (0.30 ± 0.04mm², P < 0.05), although no differences in plaque composition were noted between groups. In addition, immunofluorescence analysis revealed increased splenic B and T cell areas independent of cell number. AID depletion directly inhibits atherosclerotic plaque formation.

BAFF and APRIL counterregulate susceptibility to inflammation-induced preterm birth

Clinical evidence points to a function for B cell-activating factor (BAFF) in pregnancy. However, direct roles for BAFF-axis members in pregnancy have not been examined. Here, via utility of genetically modified mice, we report that BAFF promotes inflammatory responsiveness and increases susceptibility to inflammation-induced preterm birth (PTB). In contrast, we show that the closely related A proliferation-inducing ligand (APRIL) decreases inflammatory responsiveness and susceptibility to PTB. Known BAFF-axis receptors serve a redundant function in signaling BAFF/APRIL presence in pregnancy. Treatment with anti-BAFF/APRIL monoclonal antibodies or BAFF/APRIL recombinant proteins is sufficient to manipulate susceptibility to PTB. Notably, macrophages at the maternal-fetal interface produce BAFF, while BAFF and APRIL presence divergently shape macrophage gene expression and inflammatory function. Overall, our findings demonstrate that BAFF and APRIL play divergent inflammatory roles in pregnancy and provide therapeutic targets for mitigating risk of inflammation-induced PTB.

Pleiotropic effects of BAFF on the senescence-associated secretome and growth arrest

Senescent cells release a variety of cytokines, proteases, and growth factors collectively known as the senescence-associated secretory phenotype (SASP). Sustained SASP contributes to a pattern of chronic inflammation associated with aging and implicated in many age-related diseases. Here, we investigated the expression and function of the immunomodulatory cytokine BAFF (B-cell activating factor; encoded by the TNFSF13B gene), a SASP protein, in multiple senescence models. We first characterized BAFF production across different senescence paradigms, including senescent human diploid fibroblasts (WI-38, IMR-90) and monocytic leukemia cells (THP-1), and tissues of mice induced to undergo senescence. We then identified IRF1 (interferon regulatory factor 1) as a transcription factor required for promoting TNFSF13B mRNA transcription in senescence. We discovered that suppressing BAFF production decreased the senescent phenotype of both fibroblasts and monocyte-like cells, reducing IL6 secretion and SA-β-Gal staining. Importantly, however, the influence of BAFF on the senescence program was cell type-specific: in monocytes, BAFF promoted the early activation of NF-κB and general SASP secretion, while in fibroblasts, BAFF contributed to the production and function of TP53 (p53). We propose that BAFF is elevated across senescence models and is a potential target for senotherapy.

Hypertrophic pachymeningitis in ANCA-associated vasculitis: Clinical and immunopathological features and insights

Hypertrophic pachymeningitis (HP) is an inflammatory disorder characterized by intracranial and spinal thickened dura mater, leading to several neurological manifestations including headaches, cranial neuropathies, seizures, and sensorimotor disorders. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a crucial disease that is implicated in the development of immune-mediated HP. HP is observed throughout the clinical course of AAV, and 3%-4% of patients with AAV experience HP as the initial clinical episode. However, patients with ANCA-related HP are unclassifiable in the classification criteria of AAV when HP is the only manifestation, suggesting that ANCA-related HP can be identified as a central nervous system-limited type of AAV. Among patients with AAV, those who develop HP have predominantly been classified as having granulomatosis with polyangiitis (GPA). Myeloperoxidase-ANCA positivity has been more frequently demonstrated than proteinase 3-ANCA positivity in patients with ANCA-related HP. The ear, nose, and throat manifestations, such as otitis media, sinusitis, and mastoiditis, as well as mucous membranes/eyes manifestations including sudden visual loss, are robustly associated with HP in AAV. The histology of thickened dura mater tissues includes fibrotic changes and infiltration of several immunocompetent cells, but the typical findings of GPA, such as granulomatous inflammation with necrotizing vasculitis, are not observed in all patients with ANCA-related HP. Corticosteroids are the first-line therapy for ANCA-related HP, while the concomitant use of immunosuppressive agents including cyclophosphamide, methotrexate, and mycophenolate mofetil, is an ideal strategy for achieving remission. Rituximab is a useful agent in refractory ANCA-related HP.

Evaluation of BAFF, APRIL and CD40L in Ocrelizumab-Treated pwMS and Infectious Risk

BACKGROUND

The anti-CD20 monoclonal antibody ocrelizumab has been widely employed in the treatment of people with multiple sclerosis (pwMS). However, its B-cell-depleting effect may induce a higher risk of infectious events and alterations in the secretion of B-cell-activating factors, such as BAFF, APRIL and CD40L.

METHODS

The aim of this study was to investigate plasma BAFF, APRIL and CD40L levels and their relationship with infectious risk in ocrelizumab-treated pwMS at baseline (T0), at 6 months (T6) and at 12 months (T12) after starting the treatment. As a control group, healthy donors (HD) were enrolled too.

RESULTS

A total of 38 pwMS and 26 HD were enrolled. At baseline, pwMS showed higher plasma BAFF (p < 0.0001), APRIL (p = 0.0223) and CD40L (p < 0.0001) levels compared to HD. Compared to T0, plasma BAFF levels were significantly increased at both T6 and T12 (p < 0.0001 and p < 0.0001, respectively). Whereas plasma APRIL and CD40L levels were decreased at T12 (p = 0.0003 and p < 0.0001, respectively). When stratifying pwMS according to the development of an infectious event during the 12-month follow-up period in two groups-with (14) and without an infectious event (24)-higher plasma BAFF levels were observed at all time-points; significantly, in the group with an infectious event compared to the group without an infectious event (T0: p < 0.0001, T6: p = 0.0056 and T12: p = 0.0400). Conclusions: BAFF may have a role as a marker of immune dysfunction and of infectious risk.

TNFSF13B rs9514828 gene polymorphism and soluble B cell activating factor levels: Association with apical periodontitis

AIM

The aim of this case-control study was to evaluate the association between the TNFSF13B rs9514828 (-871 C > T) polymorphism and soluble BAFF (sBAFF) in apical periodontitis (AP) patients.

METHODOLOGY

Two hundred and sixty one healthy subjects (HS) and 158 patients with AP classified as: 46 acute apical abscess (AAA), 81 primary AP (pAP) and 31 secondary AP (sAP) patients were included. Genomic DNA (gDNA) was extracted from peripheral blood cells according to the salting out method. The TNFSF13B rs9514828 (NC_000013.11:g.108269025C > T) were identified using polymerase chain reaction (PCR) followed by restriction fragment length polymorphisms (RFLP). Serum sBAFF levels were measured by ELISA test. The chi-squared or Fisher's exact test was performed. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the risk of AP associated with the rs9514828. The Mann-Whitney U test and Kruskal-Wallis analysis were used for non-normally distributed data. Differences were considered significant with a p-value <.05.

RESULTS

No differences in the genotype/allele frequencies were shown between HS and patients with AAA. However, the TT genotype (OR = 2.68, 95% CI: 1.10-6.53; p = .025) and T allele (OR = 1.46, 95% CI: 1.00-2.12; p = .045) were associated with increased risk of pAP. In contrast, the minor allele T significantly decreased the risk of sAP (OR = 0.49, 95% CI: 0.024-0.99; p = .043). sBAFF serum levels were increased in AAA and pAP compared with HS (p < .01 and p = .021, respectively). The AAA patients had higher sBAFF serum levels than pAP (p = .034) and sAP (p < .01).

CONCLUSIONS

These results suggest that the TNFSF13B rs9514828 (-871 C > T) polymorphism is associated with pAP susceptibility and that BAFF is a cytokine that might be involved in acute and chronic AP. The future exploration of the rs9514828 polymorphism in other AP cohorts is recommended.

Comparing species-different responses in pulmonary fibrosis research: Current understanding of in vitro lung cell models and nanomaterials

Pulmonary fibrosis (PF) is a chronic, irreversible lung disease that is typically fatal and characterized by an abnormal fibrotic response. As a result, vast areas of the lungs are gradually affected, and gas exchange is impaired, making it one of the world's leading causes of death. This can be attributed to a lack of understanding of the onset and progression of the disease, as well as a poor understanding of the mechanism of adverse responses to various factors, such as exposure to allergens, nanomaterials, environmental pollutants, etc. So far, the most frequently used preclinical evaluation paradigm for PF is still animal testing. Nonetheless, there is an urgent need to understand the factors that induce PF and find novel therapeutic targets for PF in humans. In this regard, robust and realistic in vitro fibrosis models are required to understand the mechanism of adverse responses. Over the years, several in vitro and ex vivo models have been developed with the goal of mimicking the biological barriers of the lung as closely as possible. This review summarizes recent progress towards the development of experimental models suitable for predicting fibrotic responses, with an emphasis on cell culture methods, nanomaterials, and a comparison of results from studies using cells from various species.

Advances in the Pathogenesis and Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a genetically predisposed, female-predominant disease, characterized by multiple organ damage, that in its most severe forms can be life-threatening. The pathogenesis of SLE is complex and involves cells of both innate and adaptive immunity. The distinguishing feature of SLE is the production of autoantibodies, with the formation of immune complexes that precipitate at the vascular level, causing organ damage. Although progress in understanding the pathogenesis of SLE has been slower than in other rheumatic diseases, new knowledge has recently led to the development of effective targeted therapies, that hold out hope for personalized therapy. However, the new drugs available to date are still an adjunct to conventional therapy, which is known to be toxic in the short and long term. The purpose of this review is to summarize recent advances in understanding the pathogenesis of the disease and discuss the results obtained from the use of new targeted drugs, with a look at future therapies that may be used in the absence of the current standard of care or may even cure this serious systemic autoimmune disease.

The BAFF-APRIL System in Cancer

B cell-activating factor (BAFF; also known as CD257, TNFSF13B, BLyS) and a proliferation-inducing ligand (APRIL; also known as CD256, TNFSF13) belong to the tumor necrosis factor (TNF) family. BAFF was initially discovered as a B-cell survival factor, whereas APRIL was first identified as a protein highly expressed in various cancers. These discoveries were followed by over two decades of extensive research effort, which identified overlapping signaling cascades between BAFF and APRIL, controlling immune homeostasis in health and driving pathogenesis in autoimmunity and cancer, the latter being the focus of this review. High levels of BAFF, APRIL, and their receptors have been detected in different cancers and found to be associated with disease severity and treatment response. Here, we have summarized the role of the BAFF-APRIL system in immune cell differentiation and immune tolerance and detailed its pathogenic functions in hematological and solid cancers. We also highlight the emerging therapeutics targeting the BAFF-APRIL system in different cancer types.