Cell Activating Factor Research Articles

Patients with IgA Nephropathy Show Abnormal Frequencies of B cell Subsets and Unconventional T Cells and High Levels of Gd-IgA1 Coated Gut Bacteria

BackgroundMucosal inflammation is involved in the pathophysiology of Immunoglobulin-A nephropathy (IgAN), but peripheral immune phenotype analyses of IgAN patients often do not include unconventional T cells, the major subset in mucosal immunity. MethodsWe measured serum total IgA, gd-IgA1, secretory IgA, B cell activating factor (BAFF), and A proliferation-inducing ligand (APRIL) in 66 IgAN patients and 30 healthy controls (HC). We also quantified total IgA and gd-IgA1 in stool supernatant and coated on bacteria. In 35 patients and 14 controls, we performed extensive phenotyping (CyTOF) of circulating immune cells, including unconventional T cells [mucosal associated invariant T (MAIT) cells, γδ T, and NK T cells]. The results were validated using RNAseq data from a larger cohort of 179 patients with IgAN, 140 patients with minimal change disease (MCD), and 91 HC. ResultsIgAN patients had higher circulating levels of total IgA, gd-IgA1, and APRIL and higher IgA- and gd-IgA1-coated gut bacteria than controls, while serum levels of secretory IgA and BAFF did not differ between groups. IgAN patients showed more class switched memory and double negative B cells than controls. MAIT cells and γδ T cells were significantly lower, and CD4- CD8- NK T cells significantly higher in IgAN patients than in HC. We validated the significant decrease in MAIT cells in an independent cohort of patients with IgAN. ConclusionThe data indicate that patients with IgAN have increased circulating class switched memory and double negative B cells associated with abnormal T cell immunity, involving defects in unconventional T cell frequency. This may suggest putative alterations at mucosal sites due to cell migration leading to altered IgA production.

Venetoclax dose escalation rapidly activates a BAFF/BCL-2 survival axis in chronic lymphocytic leukemia

AbstractVenetoclax, a first-in-class BH3 mimetic drug that targets BCL-2, has improved the outcomes of patients with chronic lymphocytic leukemia (CLL). Early measurements of the depth of the venetoclax treatment response, assessed by minimal residual disease, are strong predictors of long-term clinical outcomes. However, there are limited data on the early changes induced by venetoclax treatment that might inform strategies to improve responses. To address this gap, we conducted longitudinal mass cytometric profiling of blood cells from patients with CLL during the first 5 weeks of venetoclax monotherapy. At baseline, we resolved CLL heterogeneity at the single-cell level to define multiple subpopulations in all patients based on proliferative, metabolic, and cell survival proteins. Venetoclax induced a significant reduction in all CLL subpopulations and caused rapid upregulation of the prosurvival BCL-2, BCL-XL, and mantle cell lymphoma-1 proteins in surviving cells, which had reduced sensitivity to the drug. In mouse models, the venetoclax-induced elevation of survival proteins in B cells and CLL-like cells that persisted was recapitulated, and genetic models demonstrated that extensive apoptosis and access to the B cell cytokine, B cell activating factor (BAFF), were essential. Accordingly, in patients with CLL who were treated with venetoclax or the anti-CD20 antibody obinutuzumab there was marked elevation in BAFF and an increase in prosurvival proteins in leukemic cells that persisted. Overall, these data highlight the rapid adaptation of CLL cells to targeted therapies through homeostatic factors and support cotargeting of cytokine signals to achieve deeper and more durable long-term responses.

Spatiotemporal cellular dynamics of germinal center reaction in COVID-19 lung draining lymph node based on imaging-based spatial transcriptomics

Although lymph node structures may be compromised in severe SARS-CoV-2 infection, the extent and parameters of recovery in convalescing patients remain unclear. Therefore, this study aimed to elucidate the nuances of lymphoid structural recovery and their implications for immunological memory in non-human primates infected with SARS-CoV-2. To do so, we utilized imaging-based spatial transcriptomics to delineate immune cell composition and tissue architecture formation in the lung draining lymph nodes during primary infection, convalescence, and reinfection from COVID-19. We noted the establishment of a germinal center with memory B cell differentiation within lymphoid follicles during convalescence accompanied by contrasting transcriptome patterns indicative of the acquisition of follicular helper T cells versus the loss of regulatory T cells. Additionally, repopulation of germinal center-like B cells was observed in the medullary niche with accumulating plasma cells along with enhanced transcriptional expression of B cell activating factor receptor over the course of reinfection. The spatial transcriptome atlas produced herein enhances our understanding of germinal center formation with immune cell dynamics during COVID-19 convalescence and lymphoid structural recovery with transcriptome dynamics following reinfection. These findings have the potential to inform the optimization of vaccine strategies and the development of precise therapeutic interventions in the spatial context.

B Cell-Activating Factor (BAFF) and Ubiquitin Enzyme A20 as Functional Proteins in Targeted Therapy on Patients with Systemic Lupus Erythematosus

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by inflammation. The pathogenesis of SLE involves key proteins, including B cell-activating factor (BAFF) and the ubiquitin enzyme A20, both serving as negative regulators of inflammation and contributing to B cell homeostasis. In this review, focused on interventions directed at BAFF and the A20 enzyme, utilizing monoclonal antibodies either independently or in conjunction with conventional therapy for SLE patients.METHODS: A literature search was conducted on the PubMed platform by combining various terms, including "B-cells activating factor", "TNFAIP3 protein (human)", "therapeutics" or "drug therapy", and "lupus erythematosus, systemic" (limited to the last 10 years). From total of 104 articles discovered in thr search, the total number of articles collected after being filtered was 27 articles.RESULTS: Clinical development and evaluation have been conducted regarding the use of appropriate therapy for SLE patients. Selective BAFF inhibitor has been tested in clinical trials as a blocking agent in BAFF receptor (BAFF-R) and signaling nuclear factor-kappaB (NF-κB) by A20 bindings to inhibit the activation of autoreactive B cells. Just like other antimonoclonal therapies, BAFF and the A20 enzyme can be used as therapeutic targets with a single use or combined with the standard therapy in patients with SLE. In addition, the use of BAFF and A20 also shown to have safe side effects in patients with SLE. CONCLUSION: BAFF protein and A20 enzyme present promising therapeutic targets for managing autoimmune diseases like SLE. Therapeutic interventions can be administered individually or in conjunction with standard treatments. KEYWORDS: systemic lupus erythematosus, therapeutic targets, BAFF, A20

BAFF overexpression in triple-negative breast cancer promotes tumor growth by inducing IL-10-secreting regulatory B cells that suppress anti-tumor T cell responses.

Despite BAFF's (B cell activating factor, BAFF) known influence on B cell survival and proliferation, its specific effects within the tumor microenvironment remain unclear. We aimed to elucidate how BAFF overexpression in breast cancer cells impacts tumor growth and the functions of T and B cells in the tumor microenvironment. BAFF was overexpressed in the 4T1 mouse triple-negative breast cancer cell line, and tumor growth, immune cell infiltration, and activity were assessed in vitro and in vivo using flow cytometry, co-culture assays, and mouse tumor models with B cell depletion. BAFF overexpression in 4T1 cells promoted tumor growth in vivo, suppressed CD8+ T cell activity, and increased IL-10-secreting CD5+ regulatory B cells in tumors. 4T1/BAFF cells directly enhanced IL-10 production in CD5+ B cells via BAFF/BAFF-receptor interactions, and IL-10 from CD5+ B cells inhibited IFN-γ secretion by T cells. B cell depletion partially reversed the tumor-promoting effects of BAFF overexpression. Our study reveals a novel mechanism by which BAFF can foster tumor progression, with the induction of IL-10-secreting regulatory B cells that suppress anti-tumor T cell responses appearing to be a key component of BAFF's tumor-promoting activity. These findings underscore the complex immunomodulatory effects that BAFF exerts in the tumor microenvironment and point to BAFF-induced regulatory B cells as a potential new therapeutic target in breast cancer that warrants further investigation.

Serum inflammatory biomarkers associated with disease severity and response to dupilumab treatment in bullous pemphigoid: A cluster analysis

BackgroundDupilumab, a novel therapy targeting the T helper (Th) 2-mediated inflammation, is showing clinical benefits in treating bullous pemphigoid (BP). However, limited research investigated the serum biomarkers that reflect the inflammation alterations throughout the disease course. ObjectivesTo explore the changes of the serum inflammatory biomarkers under dupilumab therapy in BP and establish their correlations with disease severity and clinical outcomes. MethodsThis exploratory study evaluated serum samples from 40 patients with BP at baseline, 30 of these patients following 16-week dupilumab therapy, and 20 senior healthy controls. Serum levels of 29 cytokines and chemokines were quantified using the Magnetic Luminex Assay. ResultsTwo distinct clusters based on serum inflammatory profiles were identified. The first cluster, characterized by elevated levels of inflammatory activation, exhibited worse disease severity and poorer remission outcomes. Following the 16-week dupilumab therapy regimen, a significant suppression of Th2-mediated inflammation in the serum was observed, alongside a relative upregulation of Th1 responses. Patients treated with adjuvant systemic steroids exhibited an enhanced suppression of B cell activating factor compared to those receiving dupilumab alone. Significant correlations were unveiled between Th2 biomarkers and clinical scores, eosinophil counts, and anti-BP180 immunoglobulin G levels. Baseline levels of CCL18, Periostin, interleukin (IL)-6, and IL-16 constitute an optimal combination to distinguish between inflammatory clusters. ConclusionsCluster analysis of serum inflammatory biomarkers provided novel insights into the heterogeneity of the inflammation profiles in BP. Baseline levels of CCL18, Periostin, IL-6, IL-16 emerged as effective predictors for disease severity and therapy response to dupilumab.

A serum B-lymphocyte activation signature is a key distinguishing feature of the immune response in sarcoidosis compared to tuberculosis

Sarcoidosis and tuberculosis (TB) are two granulomatous diseases that often share overlapping clinical features, including uveitis. We measured 368 inflammation-related proteins in serum in both diseases, with and without uveitis from two distinct geographically separated cohorts: sarcoidosis from the Netherlands and TB from Indonesia. A total of 192 and 102 differentially expressed proteins were found in sarcoidosis and active pulmonary TB compared to their geographical healthy controls, respectively. While substantial overlap exists in the immune-related pathways involved in both diseases, activation of B cell activating factor (BAFF) signaling and proliferation-inducing ligand (APRIL) mediated signaling pathways was specifically associated with sarcoidosis. We identified a B-lymphocyte activation signature consisting of BAFF, TNFRSF13B/TACI, TRAF2, IKBKG, MAPK9, NFATC1, and DAPP1 that was associated with sarcoidosis, regardless of the presence of uveitis. In summary, a difference in B-lymphocyte activation is a key discriminative immunological feature between sarcoidosis/ocular sarcoidosis (OS) and TB/ocular TB (OTB).

Serum BAFF level is associated with the presence and severity of coronary artery disease and acute myocardial infarction

ObjectiveThe aim of this study was to investigate the relationship between circulating levels of B cell activating factor (BAFF) and the presence and severity of coronary artery disease (CAD) and acute myocardial infarction (AMI) in humans, as its biological functions in this context remain unclear.MethodsSerum BAFF levels were measured in a cohort of 723 patients undergoing angiography, including 204 patients without CAD (control group), 220 patients with stable CAD (CAD group), and 299 patients with AMI (AMI group). Logistic regression analyses were used to assess the association between BAFF and CAD or AMI.ResultsSignificantly elevated levels of BAFF were observed in patients with CAD and AMI compared to the control group. Furthermore, BAFF levels exhibited a positive correlation with the SYNTAX score (r = 0.3002, P < 0.0001) and the GRACE score (r = 0.5684, P < 0.0001). Logistic regression analysis demonstrated that increased BAFF levels were an independent risk factor for CAD (adjusted OR 1.305, 95% CI 1.078–1.580) and AMI (adjusted OR 2.874, 95% CI 1.708–4.838) after adjusting for confounding variables. Additionally, elevated BAFF levels were significantly associated with a high GRACE score (GRACE score 155 to 319, adjusted OR 4.297, 95% CI 1.841–10.030). BAFF exhibited a sensitivity of 75.0% and specificity of 71.4% in differentiating CAD patients with a high SYNTAX score, and a sensitivity of 75.5% and specificity of 72.8% in identifying AMI patients with a high GRACE score.ConclusionCirculating BAFF levels serve as a valuable diagnostic marker for CAD and AMI. Elevated BAFF levels are associated with the presence and severity of these conditions, suggesting its potential as a clinically relevant biomarker in cardiovascular disease.

B cell targeting in IgA nephropathy.

The "multi-hit theory/4-hit theory" pathogenesis hypothesis is widely accepted and IgA nephropathy (IgAN) is understood to be a disease originating from Hit 1, galactose deficient IgA1 (GdIgA1). The chronic repetitive activation of the complement pathway (alternative and lectin pathways) and the subsequent inflammation results in progressive glomerular damage that spills over into increased intraglomerular pressure and other hemodynamic changes, increased urinary protein, glomerulosclerosis, and tubulointerstitial fibrosis. The basic pathophysiology of this disease is the progression of a mixture of such acute and chronic pathologies. Currently, a number of new drugs has emerged as promising agents, such as complement regulators, endothelin receptor antagonists, and SGLT2 inhibitors, which are associated with each pathological step after glomerular deposition of GdIgA1/immune complexes. On the other hand, the molecular mechanisms of GdIgA1 production are gradually being elucidated, and the development of several novel therapeutic agents targeting the responsible B cells and their international clinical trials are progressing. These agents that inhibit or control the production of the Hit1, GdIgA1, are highly expected as essential therapies for this disease. The large body of clinical and basic research findings to date strongly suggest that nephritogenic GdIgA1 is a polymeric IgA1 of mucosal origin. In addition, the B cells involved in its nephritogenic GdIgA1 production are mainly differentiated mature B cells such as plasma cells, which may migrate to the bone marrow as well as the mucosa. The innate immune system in the mucosa, especially Toll-like receptors (TLRs), is thought to be involved in their production. Among TLRs, TLT9 and TLR7, which recognize bacterial and viral unmethylated DNA and RNA, have been reported to be involved. The mucosal activation of these TLRs is associated with the production of APRIL (A Proliferation Inducing Ligand) and BAFF (B cell activating factor), which are TNF superfamily cytokines involved in B cell maturation, survival, and IgA class switching, and may also be involved in the production of nephritogenic GdIgA1. It is still inconclusive whether APRIL or BAFF is more closely involved in the production of nephritogenic GdIgA1. Phenotypes in transgenic animal models suggest BAFF involvement, however, a genome wide association study (GWAS) analysis of human IgAN has identified APRIL, not BAFF, as a candidate gene. Based on the above background, several international clinical trials are underway for drugs such as TLR regulators (hydroxychloroquine), anti-APRIL drugs, anti-BAFF drugs, APRIL/BAFF receptor (TACI) binding inhibitors, and cytoreductive drugs (proteasome inhibitors, anti-CD38 antibodies) to inhibit nephritogenic GdIgA1 production in responsible B cells. This session will provide an overview of the responsible B cells, their GdIgA1 production mechanism, and ongoing drugs.

Comprehensive Analysis of scRNA-Seq and Bulk RNA-Seq Reveals Transcriptional Signatures of Macrophages in Intrahepatic Cholestasis of Pregnancy.

Intrahepatic cholestasis of pregnancy (ICP) is a disorder that characterized by maternal pruritus, abnormal liver function, and an elevation in total bile acid concentrations during pregnancy. Immune factors have been recognized as playing a vital role in the mechanism of ICP. However, the underlying mechanisms regulating dysfunctional immune cells and immune genes remain to be fully elucidated. Single-cell RNA sequencing and bulk RNA sequencing data of the placenta were downloaded from the SRA database. The AUCell package, Monocle package and SCENIC package were utilized to explored immune cell activity, cell trajectory and transcription factor, respectively. GO, KEGG, and GSEA were employed to explore potential biological mechanisms. Cell-cell communications were further investigated using the CellChat package. RT-PCR, and Western blot were used to verify the gene expression in placenta. In placenta cells, macrophages were found to be significantly increased in ICP. Additionally, macrophages exhibited the highest immune gene score and were divided into four subclusters (MF1-4). Our analysis revealed significant elevations in MF2, associated with LPS response and antigen presentation, and MF4, associated with TNF and cytokine production. MF3 displayed an anti-inflammatory phenotype. MF1, closely related to ribosomes and proteins, exhibited a sharp decrease. Although ICP maintained an anti-inflammatory state, macrophage trajectories showed a gradual progression toward inflammation. Subsequently, we confirmed that cytokine- and chemokine-related signaling pathways were emphasized in macrophages. Within the CXCL signaling pathway, the increased expression of CXCL1 in macrophages can interact with CXCR2 in neutrophils, potentially inducing macrophage infiltration, stimulating neutrophil chemotaxis, and leading to an inflammatory response and cellular damage. In conclusion, we firstly revealed the transcriptional signatures of macrophages in ICP and discovered a tendency toward an inflammatory state. This study also provides new evidence that the CXCL1-CXCR2 axis may play an important role in the pathogenesis of ICP.

T cell Dissimilarities in B Cell Activating Factor-Deficient Versus B Cell Activating Factor Receptor 3-Deficient Systemic Lupus Erythematosus-Prone NZM 2328 Mice as Contributors to Their Divergent Clinical Outcomes.

We assessed the contributions of B cell and T cell subsets to the disparate clinical outcomes in NZM.Baff-/- and NZM.Br3-/- mice. We assessed in NZM wild-type, NZM.Baff-/-, and NZM.Br3-/- mice numbers and percentages of B cells and subsets, T cells and subsets, and in vivo proliferation and survival of forkhead box P3 (Foxp3)+ cells by fluorescence-activated cell sorting. Relationships between percentages of Foxp3+ cells and numbers of CD19+ and CD4+ cells were assessed by linear regressions. In each age and sex cohort, percentages and numbers of CD19+ cells were similar in NZM.Baff-/- and NZM.Br3-/- mice. Percentages of CD3+ and CD4+ cells were greater in NZM.Br3-/- than in NZM.Baff-/- mice, with the CD4 to CD3 cell ratios being greater in NZM.Br3-/- than in NZM.Baff-/- mice and percentages of Foxp3+ cells in NZM.Br3-/- mice being lower than in NZM.Baff-/- mice. Percentages of Foxp3+ cells correlated positively with CD19+ cells in NZM.Baff-/- mice but negatively in NZM.Br3-/- mice. In vivo proliferation and survival of Foxp3+ cells were lower in NZM.Baff-/- mice than in NZM.Br3-/- mice. Differences between NZM.Baff-/- and NZM.Br3-/- mice in Foxp3+ cells and their relationships with CD19+ cells may have more to do with their divergent clinical outcomes than do differences in numbers of B cells. These unexpected findings suggest that B cell activating factor (BAFF)-B cell maturation antigen (BCMA) or BAFF-Transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) interactions may help drive development of clinical systemic lupus erythematosus (SLE) even under conditions of considerable B cell depletion. Insufficient blocking of BAFF-BCMA and BAFF-TACI interactions may lie at the heart of incomplete clinical response to BAFF-targeting agents in human SLE.

Current Management of Warm Autoimmune Haemolytic Anaemia and Recent Advancements in Research: Interview with a Key Opinion Leader

Warm autoimmune haemolytic anaemia (wAIHA) is a rare, life-threatening disorder caused by autoantibodies that lead to the premature destruction of erythrocytes (haemolysis). There is currently no licensed targeted therapy for wAIHA. Until recently, there has been little research attention on autoimmune haemolytic anaemias (AIHA), with few developments in the field over the past 20 years. The last 3 years have seen a surge in research interest in wAIHA, with the development of potential new therapies for this rare disorder. For this article, the EMJ conducted an interview in June 2024 with key opinion leader, Bruno Fattizzo, from the University of Milan, and Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy, to raise awareness of wAIHA, and explore recent advancements in research on this disease. Fattizzo, who has a wealth of experience and expertise in the clinical management of wAIHA, provided valuable insights into topics such as the clinical and quality of life (QoL) impact of wAIHA on the patient; current management of wAIHA, including steroids, rituximab, immunosuppressants, splenectomy, anticoagulant prophylaxis, and recombinant erythropoietin; and remaining unmet needs in the disease area. Also discussed were potential future therapies for this autoimmune disorder, including tyrosine kinase inhibitors, neonatal fragment crystallisable receptor (FcRn) inhibitors, and B cell activating factor receptor (BAFF-R) antagonists, and the challenges involved in managing patients with wAIHA. Finally, Fattizzo described the patient experience of living with wAIHA, proposed how best to raise awareness of wAIHA among healthcare professionals, the scientific community, patients, and the public, and outlined what the future of the management of patients with wAIHA might look like.

B Cell-activating factor (BAFF): A promising trans-nosographic biomarker of inflammation and autoimmunity in bipolar disorder and schizophrenia

Immune dysregulation is an important aspect of schizophrenia (SZ) and bipolar disorders (BD) pathophysiology, including not only inflammatory but also autoimmune process reflective of abnormal humoral immune responses. Given that B cell-activating factor (BAFF) is an integral aspect of B lymphocyte regulation, the current study investigated BAFF in SZ and BD. 255 SZ patients, 407 BD patients and 185 healthy controls (HC) were investigated across three aspects of soluble BAFF (sBAFF) by (i) comparing sBAFF circulatory levels across SZ, BD and HC, (ii) determining potential correlations between the circulating levels of sBAFF and the genotype distribution of a functionally relevant polymorphism, namely the TNFSF13B 3′UTR insertion-deletion polymorphism (GCTGT>A), (iii) analyzing relationships between both sBAFF levels and 3′UTR insertion-deletion genotypes and disease risk, patients clinical characteristics and circulating levels of potent inflammatory molecules. In addition, in subsets of patients, we also searched for possible correlations between sBAFF levels and stigma of past infectious events as well as positivity for circulating systemic autoantibodies or those directed against central nervous system (CNS) structures. Studying blood derived serum and DNA, weobserved that circulating sBAFF levels were significantly higher in SZ and BD patients, versus HC (p = 5.3*10-10and p = 4.4*10-09). Patients experiencing acute episodes, versus stable patients, in between acute episodes, exhibited higher sBAFF levels (p = 0.017).In SZ patients, positive correlations were observed between elevated sBAFF levels and: (i) elevated positive psychotic symptoms (PANSS pos), (ii) history of childhood trauma (physical abuse), and (iii) low scores on global functioning (GAF) (p = 0.024, p = 0.024, and p = 0.041).We also found that the distribution of the BAFF Ins/Del genotypes was significantly correlated with circulating sBAFF levels in SZ and BD patients (p = 0.0004). Elevated sBAFF levels were also correlated with increased levels of pro-inflammatory markers in both SZ and BD cohorts (p < 0.001). Regarding infectious stigma, only patients seropositive, versus seronegative, for herpes simplex virus (HSV)1 immunoglobulin (Ig)G antibodies exhibited a significant association with high sBAFF levels (p = 0.013). In contrast, positivity for systemic or CNS autoantibodies was significantly associated with reduced sBAFF levels, compared to patients without autoantibodies (p = 0.0017). Overall, our findings indicate that BAFF may be a promising trans-nosographic biomarker of inflammation that is likely to offer predictive, diagnostic, and prognostic tools for the management of SZ and BD. The results therefore have practicable clinical utility given the availability of immunotherapeutic treatment options including targeted monoclonal antibodies against BAFF.

PD1+CD4+ T cells promote receptor editing and suppress autoreactivity of CD19+CD21low B cells within the lower respiratory airways in adenovirus pneumonia

Human adenovirus (HAdV) pneumonia poses a major health burden for young children, however, factors that contribute to disease severity remain elusive. We analyzed immune cells from bronchoalveolar lavage (BAL) of children with HAdV pneumonia and found that CD19+CD21low B cells were significantly enriched in the BAL and were associated with increased autoantibody concentrations and disease severity. Myeloid cells, PD-1+CD4+ T helper cells and CD21low B cells formed tertiary lymphoid structures within the respiratory tracts. Myeloid cells promoted autoantibody production by expressing high amounts of B cell activating factor (BAFF). In contrast, PD-1+CD4+ T helper cells induced production of IgG1 and IgG3 antibodies but suppressed autoreactive IgGs by initiating B cell receptor editing. In summary, this study reveals cellular components involved in protective versus autoreactive immune pathways in the respiratory tract, and these findings provide potential therapeutic targets for severe HAdV lower respiratory tract infections.

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.

Trailblazing in adjuvant research: succinate's uncharted territory with neutrophils.

The purpose of this study is to investigate the previously unknown connection that succinate has with neutrophils in the setting of adjuvant-mediated immunological enhancement. It has been discovered that succinates stimulate the recruitment of neutrophils in immunization sites, which in turn induces the expression of what is known as neutrophil-derived B cell-activating factor (BAFF). Further amplification of vaccine-induced antibody responses is provided via the succinate receptor 1-interferon regulatory factor 5 (SUCNR1-IRF5)-BAFF signaling pathway, which provides insights into a unique mechanism for immunological enhancement.NEW & NOTEWORTHY This study explores the role of succinate as a vaccine adjuvant, revealing its capacity to enhance neutrophil recruitment at immunization sites, which boosts B cell activation through the succinate receptor 1-interferon regulatory factor 5-B cell-activating factor (SUCNR1-IRF5-BAFF) signaling pathway. Results demonstrate succinate's potential to amplify vaccine-induced antibody responses, highlighting its significance in immunological enhancement and offering new insights into the adjuvant mechanisms of action, particularly in neutrophil-mediated immune responses.

Botulinum neurotoxin serotype A inhibited ocular angiogenesis through modulating glial activation via SOCS3.

Pathological angiogenesis causes significant vision loss in neovascular age-related macular degeneration and other retinopathies with neovascularization (NV). Neuronal/glial-vascular interactions influence the release of angiogenic and neurotrophic factors. We hypothesized that botulinum neurotoxin serotype A (BoNT/A) modulates pathological endothelial cell proliferation through glial cell activation and growth factor release. A laser-induced choroidal NV (CNV) was employed to investigate the anti-angiogenic effects of BoNT/A. Fundus fluorescence angiography, immunohistochemistry, and real-time PCR were used to assess BoNT/A efficacy in inhibiting CNV and the molecular mechanisms underlying this inhibition. Neuronal and glial suppressor of cytokine signaling 3 (SOCS3) deficient mice were used to investigate the molecular mechanisms of BoNT/A in inhibiting CNV via SOCS3. In laser-induced CNV mice with intravitreal BoNT/A treatment, CNV lesions decreased > 30%; vascular leakage and retinal glial activation were suppressed; and Socs3 mRNA expression was induced while vascular endothelial growth factor A (Vegfa) mRNA expression was suppressed. The protective effects of BoNT/A on CNV development were diminished in mice lacking neuronal/glial SOCS3. BoNT/A suppressed laser-induced CNV and glial cell activation, in part through SOCS3 induction in neuronal/glial cells. BoNT/A treatment led to a decrease of pro-angiogenic factors, including VEGFA, highlighting the potential of BoNT/A as a therapeutic intervention for pathological angiogenesis in retinopathies.

Proof-of-concept study evaluating humoral primary immunodeficiencies via CJ:KREC ratio and serum BAFF level

Humoral primary immunodeficiencies are the most prevalent form of primary immunodeficiency (PID). Currently, there is no convenient method to quantify newly formed B cells. The aim of this proof-of-concept study was to quantitate the ratio of coding joints (CJs) to Kappa-deleting recombination excision circles (KRECs) and serum B cell activating factor (BAFF) in patients with humoral primary immunodeficiency and assess if they correlate with disease severity. This IRB-approved study was conducted at one academic children’s hospital. Patients with humoral PIDs and healthy controls were included. CJ and KREC levels were measured via qPCR. Serum BAFF levels were measured using Mesoscale. 16 patients with humoral PID and 5 healthy controls were included. The mean CJ:KREC ratio in the CVID, antibody deficiency syndromes, and controls groups, respectively were 13.04 ± 9.5, 5.25 ± 4.1, and 4.38 ± 2.5 (p = 0.059). The mean serum BAFF levels in CVID, antibody deficiency syndromes and controls were 216.3 ± 290 pg/mL, 107.9 ± 94 pg/mL and 50.9 ± 12 pg/mL, respectively (p = 0.271). When the CVID patients were subdivided into CVID with or without lymphoproliferative features, the BAFF level was substantially higher in the CVID with lymphoproliferation cohort (mean 372.4 ± 361 pg/mL, p = 0.031). Elevated CJ:KREC ratio was observed in CVID, although statistical significance was not achieved, likely due to the small sample size. Serum BAFF levels were significantly higher in CVID patients with lymphoproliferative features. We speculate that the CJ:KREC ratio and serum BAFF levels can be utilized in patients with humoral PID, once more extensive studies confirm this exploratory investigation.

Integrative Analysis by Mendelian Randomization and Large-Scale Single-Cell Transcriptomics Reveals Causal Links between B Cell Subtypes and Diabetic Kidney Disease

Introduction: The increasing incidence of diabetic kidney disease (DKD) and the challenges in its management highlight the necessity for a deeper understanding of its pathogenesis. While recent studies have underscored the substantial impact of circulating immunity on the development of diabetic microvascular complications such as retinopathy and neuropathy, research on circulating immunity in DKD remains limited. Methods: This study utilized Mendelian randomization analysis to explore the potential independent causal relationships between circulating immune cells and DKD pathogenesis. Additionally, a combination of single-cell disease relevance score (scDRS) and immune cell infiltration analysis was employed to map the circulating immunity landscape in DKD patients. Results: Ten immune traits, including 5 of B cells, 2 of T cells, 2 of granulocytes, and one of monocytes, were defined to be associated with the pathogenesis of DKD. Notably, IgD-CD27-B cell Absolute Count (IVW: OR, 1.102 [1.023–1.189], p = 0.011) and IgD-CD24-B cell Absolute Count (IVW: OR, 1.106 [1.030–1.188], p = 0.005) were associated with promoting DKD pathogenesis, while CD24+CD27+B cell %B cell (IVW: OR, 0.943 [0.898–0.989], p = 0.016) demonstrated a protective effect against DKD onset. The presence of B cell-activating factor receptor (BAFF-R) on CD20−CD38−B cell (IVW: OR, 0.946 [0.904–0.989], p = 0.015) and BAFF-R on IgD-CD38+B cell (IVW: OR, 0.902 [0.834–0.975], p = 0.009) also indicated a potential role in preventing DKD. scDRS analysis revealed that two main subsets of B cells, naïve B and memory B cells, had a higher proportion of DKD-related cells or a higher scDRS score of DKD phenotype, indicating their strong association with DKD. Furthermore, immune infiltrate deconvolution analysis showed a notable decrease in the circulating memory B cells and class-switched memory B cells in DKD patients compared to those of DM patients without DKD. Conclusion: Our study revealed the causal relations between circulating immunity and DKD susceptibility, particularly highlighted the potential roles of B cell subtypes in DKD development. Further studies addressing the related mechanisms would broaden the current understanding of DKD pathogenesis.

Exploring side effects of corticosteroids in myasthenia gravis: Unveiling alternatives for safer treatment

Myasthenia Gravis (MG) is a chronic organ-specific autoimmune disease that weakens voluntary muscles by affecting neuromuscular junctions. The formation of antibodies against acetylcholine receptors is the most prevalent cause. The incidence and prevalence rates of (MG) are increasing exponentially (1). In addition to symptomatic medication, corticosteroids continue to be the first-line treatment for MG due to their affordability, ease of access, and efficacy (2). Although corticosteroids are frequently prescribed, they are not without drawbacks. Long-term corticosteroid use can result in various side effects, including osteoporosis, weight gain, acne, elevated blood pressure, mood fluctuations, and a cushingoid appearance. It has also been linked to rare complications such as gastric and esophageal irritation, compressive fractures, and aseptic femoral head fracture (3). Given the hazards associated with long-term corticosteroid use in treating MG, researchers and healthcare professionals should investigate alternative MG treatments. By doing so, new and safer treatment options can be identified, which could contribute to improved treatment and substantially enhance the quality of life for MG-affected populations. Numerous nonsteroidal medications, including mycophenolate mofetil, methotrexate, and azathioprine, have demonstrated success in clinical trials for kidney transplantation, rheumatoid arthritis, and myasthenia gravis, respectively. To confirm the efficacy of these pharmaceuticals in the treatment of MG, urgent research and trials based on in vitro and animal models are required. Based on well-designed clinical trials, these also require human testing (4). The tapering of prednisone is an alternative option. Prednisone tapering is still a problem in the therapeutic management of patients with generalized MG because, although it is a useful treatment, it has a number of adverse effects that make it necessary to find the lowest possible effective dose as quickly as feasible. Rituximab and azathioprine enable quick tapering. It is necessary to evaluate and contrast the corticosteroid-sparing effect of novel treatments with that of azathioprine and rituximab. Given their impact on MG status, it's possible that these novel therapies will make it possible to drastically cut back on corticosteroids or possibly stop taking them entirely(5) The abnormal immune responses in MG can be managed and resolved with the new drugs that specifically target them. These agents include chimeric antigen receptor T [CART-T] cell therapy, autologous stem cell transplantation, B cell depleting agents (anti-CD 19 and 20, and B cell activating factor [BAFF] inhibitors), proteosome inhibitors, terminal complement C5 inhibitors, Fc receptor inhibitors, T cells, and cytokine-based therapies (subcutaneous immunoglobulin [SCIG]). ---Continue