The roles of B cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL) in allergic asthma

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.

Neutrophil depletion attenuates antibody-mediated rejection in a renal transplantation mouse model

Antibody-mediated rejection (AMR) can cause graft failure following renal transplantation. Neutrophils play a key role in AMR progression, but the exact mechanism remains unclear. We investigated the effect of neutrophils on AMR in a mouse kidney transplantation model. The mice were divided into five groups: syngeneic transplantation (Syn), allograft transplantation (Allo), and three differently treated AMR groups. The AMR mouse model was established using skin grafts to pre-sensitize recipient mice. Based on the AMR model, Ly6G-specific monoclonal antibodies were administered to deplete neutrophils (NEUT-/- + AMR) and TACI-Fc was used to block B-cell-activating factor (BAFF)/a proliferation-inducing ligand (APRIL) signaling (TACI-Fc + AMR). Pathological changes were assessed using hematoxylin-eosin and immunohistochemical staining. Banff values were evaluated using the Banff 2015 criteria. Donor-specific antibody (DSA) levels were assessed using flow cytometry, and BAFF and APRIL concentrations were measured using ELISA. Compared to the Syn and Allo groups, a significantly increased number of neutrophils and increased C4d and IgG deposition were observed in AMR mice, accompanied by elevated DSA levels. Neutrophil depletion inhibited inflammatory cell infiltration and reduced C4d and IgG deposition. Neutrophil depletion significantly decreased DSA levels after transplantation and suppressed BAFF and APRIL concentrations, suggesting a mechanism for attenuating AMR-induced graft damage. Similar results were obtained after blockading BAFF/APRIL using a TACI-Fc fusion protein. In summary, neutrophil infiltration increased in the AMR mouse renal transplantation model. Neutrophil depletion or blockading the BAFF/APRIL signaling pathway significantly alleviated AMR and may provide better options for the clinical treatment of AMR.

Unraveling the Role of Epithelial Cells in the Development of Chronic Rhinosinusitis

The pathophysiology of CRS is multifactorial and complex yet needs to be completed. Recent evidence emphasizes the crucial part played by epithelial cells in the development of CRS. The epithelial cells act as physical barriers and play crucial roles in host defense, including initiating and shaping innate and adaptive immune responses. This review aims to present a comprehensive understanding of the significance of nasal epithelial cells in CRS. New research suggests that epithelial dysfunction plays a role in developing CRS through multiple mechanisms. This refers to issues with a weakened barrier function, disrupted mucociliary clearance, and irregular immune responses. When the epithelial barrier is compromised, it can lead to the passage of pathogens and allergens, triggering inflammation in the body. Furthermore, impaired mucociliary clearance can accumulate pathogens and secretions of inflammatory mediators, promoting chronic inflammation. Epithelial cells can release cytokines and chemokines, which attract and activate immune cells. This can result in an imbalanced immune response that continues to cause inflammation. The interaction between nasal epithelial cells and various immune cells leads to the production of cytokines and chemokines, which can either increase or decrease inflammation. By comprehending the role of epithelial cells in CRS, we can enhance our understanding of the disease's pathogenesis and explore new therapeutics.

Serum levels and significance of soluble B-cell maturation antigen in childhood-onset systemic lupus erythematosus with renal involvement

OBJECTIVE

The aim of this study was to investigate serum levels of soluble B-cell maturation antigen (sBCMA) in childhood-onset systemic lupus erythematous (cSLE) patients with renal involvement, and to elucidate their association with clinical characteristics.

METHODS

116 cases of cSLE patients with renal involvement (84 females and 32 males; median age 11.6 (10.1, 12.9) years) hospitalized in Department of Pediatric Nephrology and Rheumatology, the First Affiliated Hospital, Sun Yat-sen University and 31 healthy controls (HCs) were enrolled. Serum concentrations of sBCMA were determined using enzyme-linked immunosorbent assay (ELISA). Clinical and laboratory information of cSLE patients were retrospectively analyzed.

RESULTS

Serum sBCMA levels were significantly increased in primary cSLE when compared with treated cSLE patients and HCs, whereas there was no significant difference between treated cSLE patients and HCs. Patients with high disease activity displayed higher serum sBCMA levels compared with those with no or mild to moderate disease activity. Positive correlation was observed between serum sBCMA levels and systemic lupus erythematosus disease activity index-2K (SLEDAI-2K), antinuclear antibody titers, anti-double-stranded DNA titers, erythrocyte sedimentation rate, and immunoglobulin G levels, while sBCMA levels were negatively correlated with blood white blood cell count, hemoglobin, platelet count, complement C3 and C4 levels. Serum sBCMA levels decreased as disease ameliorated after treatments among 11 cases with follow-up examinations.

CONCLUSIONS

In cSLE patients with renal involvement, serum sBCMA levels correlated significantly with disease activity, immunological, and hematological parameters, but not with renal parameters. Our results suggest the potential and significance of serum sBCMA as a biomarker in cSLE patients.

Association between the expression of toll-like receptors, cytokines, and homeostatic chemokines in SARS-CoV-2 infection and COVID-19 severity

The recent identification of the involvement of the immune system response in the severity and mortality of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection highlights the importance of cytokines and chemokines as important factors in the clinical outcomes of COVID-19. However, the impact and roles of the BAFF/APRIL cytokine system, homeostatic chemokines (CXCL12, CXCL13, CCL19, and CCL21), as well as Toll-like receptor (TLR)-3/4 in COVID-19, have not been investigated. We sought to assess the expression levels and roles of TLR3/4, BAFF, APRIL, IFN-β, homeostatic chemokines (CXCL12, CXCL13, CCL19, and CCL21), SARS-CoV-2 IgG and IgM antibodies in patients with critical (ICU) and non-ICU (mild) COVID-19 and their association with mortality and disease severity. Significant high levels of TLR-4 mRNA, IFN-β, APRIL, CXCL13, and IgM and IgG antibodies were observed in ICU patients with severe COVID-19 compared to non-ICU COVID-19 patients and healthy controls. On the other hand, BAFF and CCL21 expression were significantly upregulated in non-ICU patients with COVID-19 compared with that in critical COVID-19 patients. The two groups did not differ in TLR-3, CXCL12, and CCL19 levels. Our findings show high expression levels of some inflammatory chemokines in ICU patients with COVID-19. These findings highlight the potential utility of chemokine antagonists as an immune-based treatment for the severe form of COVID-19. We also believe that selective targeting of TLR/spike protein interactions might lead to the development of a new COVID-19 therapy.

Considerations for Novel COVID-19 Mucosal Vaccine Development

Mucosal surfaces are the first contact sites of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Most SARS-CoV-2 vaccines induce specific IgG responses but provide limited mucosal immunity. Cytokine B-cell activation factor (BAFF) and A proliferation-inducing ligand (APRIL) in the tumor necrosis factor (TNF) superfamily play key immunological functions during B cell development and antibody production. Furthermore, homeostatic chemokines, such as C-X-C motif chemokine ligand 13 (CXCL13), chemokine (C-C motif) ligand 19 (CCL19), and CCL21, can induce B- and T-cell responses to infection and promote the formation of inducible bronchus-associated lymphoid tissues (iBALT), where specific local immune responses and memory cells are generated. We reviewed the role of BAFF, APRIL, CXCL13, CCL19, and CCL21 in the activation of local B-cell responses and antibody production, and the formation of iBALT in the lung following viral respiratory infections. We speculate that mucosal vaccines may offer more efficient protection against SARS-CoV-2 infection than systematic vaccines and hypothesize that a novel SARS-CoV-2 mRNA mucosal vaccine using BAFF/APRIL or CXCL13 as immunostimulants combined with the spike protein-encoding mRNA may enhance the efficiency of the local immune response and prevent the early stages of SARS-CoV-2 replication and the rapid viral clearance from the airways.

Increased B Cell-Activating Factor Expression Is Associated with Postoperative Recurrence of Chronic Rhinosinusitis with Nasal Polyps

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common upper airway inflammatory disease with a high postoperative recurrence rate. This study is aimed at exploring the expression of B cell-activating factor (BAFF) in CRSwNP and its association with postoperative recurrence.

Methods

A total of 80 CRSwNP patients, including 40 primary CRSwNP patients and 40 recurrent CRSwNP patients, 40 chronic rhinosinusitis without nasal polyps (CRSsNP) patients, and 40 healthy controls (HC) were enrolled in this study, and the serum and tissue samples were collected. The circulating and tissue BAFF expressions were detected by enzyme-linked immunosorbent assay reverse transcription-polymerase chain reaction and immunohistochemistry. Their clinical values for predicting postoperative recurrence of CRSwNP were evaluated.

Results

We determined serum levels of BAFF were remarkably increased in the CRSwNP group than the CRSsNP and HC groups (P < 0.05), and higher concentrations of BAFF were associated with peripheral eosinophil percentage (r = 0.614, P < 0.001). The serum BAFF concentrations were significantly higher in the recurrent CRSwNP group in comparison with the primary group (P < 0.05). Multivariate analysis and receiver operating characteristic (ROC) curve presented that serum BAFF levels were associated with the postoperative recurrence in CRSwNP patients (P < 0.05). Moreover, tissue BAFF levels were significantly increased in the CRSwNP group than the HC group, especially in the recurrent CRSwNP group (P < 0.05), and enhanced BAFF RNA expressions were correlated with serum BAFF levels (r = 0.703, P < 0.001).

Conclusion

Our results elucidated that the BAFF expression was enhanced in CRSwNP patients and associated with postoperative recurrence. BAFF could be a serologic biomarker for predicting postoperative recurrence in CRSwNP patients.

Elevated Plasma Levels of CXCL13 Chemokine in Saudi Patients With Asthma Exacerbation

Background: Bronchial asthma is a lung disorder characterized by chronic allergic inflammation of the airways, and several of the immune and non-immune cells contribute to asthma's pathogenicity. B-cell activation plays an essential role in developing allergic inflammation in the lungs. CXCL13 is a potent B-cell chemoattractant chemokine, which has a crucial role in the recruitment and trafficking of B cells after interaction with its receptor CXCR5. This study is aimed to evaluate plasma levels of CXCL13 and its receptor CXCR5 in Saudi patients with asthma exacerbation relative to healthy controls.

Methods: A total of 23 patients with asthma exacerbation and 20 healthy controls participated in this study. Total immunoglobulin E (IgE) and CXCL13 protein levels were measured in the plasma of patients with asthma exacerbations and healthy controls by specific enzyme-linked immunosorbent assay (ELISA). Gene expression mRNA for CXCR5 was measured using real-time polymerase chain reaction (RT-PCR).

Results: Total IgE protein concentrations were elevated significantly in asthma exacerbation patients than that in healthy controls. CXCL13 protein levels were increased significantly in the asthma group relative to healthy controls. In addition, CXCR5 mRNA levels were elevated significantly in the asthma group than in the healthy controls.

Conclusions: Measurement of CXCL13 and CXCR5 may be used as an additional biomarker of asthma exacerbation, and targeting CXCL13 or its receptor may be used as new treatment options in asthma.

Circulating BAFF as novel biomarker in distinguishing chronic rhinosinusitis with nasal polyps endotypes and predicting postoperative recurrence

BACKGROUND

B cell-activating factor (BAFF) is a proinflammatory cytokine involved in inflammatory and allergic diseases, but its role in chronic rhinosinusitis with nasal polyps (CRSwNP) remains unclear. This study aims to explore the predictive value of circulating BAFF in CRSwNP endotypes and postoperative recurrence.

METHODS

We recruited 120 CRSwNP patients, including 68 non-eosinophilic CRSwNP (neCRSwNP) patients, 52 eosinophilic CRSwNP (CRSwNP) patients, and 60 healthy controls (HCs). Circulating BAFF levels of all participants were measured by enzyme-linked immunosorbent assay (ELISA), and receiver-operating characteristic (ROC) and logistic regression analyses were applied to assess the predictive ability of BAFF levels in distinguishing CRSwNP endotypes. All CRSwNP patients were followed for more than 3 years, and the predictive value of circulating BAFF for postoperative recurrence was evaluated.

RESULTS

Serum BAFF levels were elevated in CRSwNP patients compared with the HCs (P < 0.01) and significantly higher in eCRSwNP patients. The increased serum BAFF concentrations positively correlated with blood eosinophil counts and percentages, tissue eosinophil counts, and serum total IgE (P < 0.05). The ROC curve showed that serum BAFF exhibited strong discriminative ability for eCRSwNP. Finally, 99 CRSwNP patients completed the follow-up schedule, 65 patients were classified into non-recurrence group and the other 34 patients were categorized into recurrence group. Serum BAFF levels were significantly higher in recurrence group than non-recurrence group (P < 0.001), and the ROC curve suggested a high predictive value of serum BAFF in predicting postoperative recurrence. Moreover, logistic regression and Kaplan-Meier curves showed that serum BAFF was an independent risk factor for postoperative recurrence (P < 0.05).

CONCLUSION

Our data suggested that serum BAFF levels were upregulated in CRSwNP patients and correlated with mucosal eosinophil infiltration severity. Serum BAFF seemed to be a novel biomarker for preoperatively distinguishing CRSwNP endotypes and predicting postoperative recurrence.

The Construction and Comprehensive Analysis of a ceRNA Immunoregulatory Network and Tissue-Infiltrating Immune Cells in Atrial Fibrillation

Background

At present, the mechanisms behind atrial fibrillation (AF) pathogenesis are still unclear. We construct a ceRNA immunoregulatory network to further understand the mechanism of AF.

Methods

Four AF mRNA datasets from the Gene Expression Omnibus (GEO) database were integrated by SVA method. AF-related immune genes (AF-IRGs) were selected via combining ImmPort database with the genes in the module most associated with AF obtained by a weighted gene coexpression network analysis (WGCNA). Then, circRNA and miRNA expressions from the GEO database were extracted and mapped with related databases. Next, an immune-related circRNA-miRNA-mRNA ceRNA network was constructed and hub genes were filtered from a protein–protein interaction (PPI) network, and the differentially expressed (DE) hub genes in AF were further screened. Additionally, immune infiltration was investigated in AF by using CIBERSORT. Subsequently, the relationships between DE hub genes and AF-related infiltrating immune cells were performed by using Pearson correlation coefficients. Ulteriorly, the immune-cells-related ceRNA subnetwork in AF was built.

Results

A total of 95 AF-IRGs were detected, and an immune-related ceRNA network in AF was constructed with 12 circRNAs, 7 miRNAs and 50 mRNAs. The immune infiltration analysis indicated that a higher level of neutrophils, as well as a lower level of T cells regulatory (Tregs) and NK cells activated in AF. Four DE hub genes (CXCL12, IL7R, TNFSF13B, CD8A) were associated with Tregs or NK cells activated immune cells (P < 0.05). Tregs or NK cells activated immune cells-related ceRNA subnetwork including 5 circRNAs (has_circ_0001190, has_circ_0006725, has_circ_0079284, has_circ_0005299, and has_circ_0002103), 4 miRNAs (has-miR-198, has-miR-623, has-miR-1246, and has-miR-339-3p) and 4 DE hub genes was eventually constructed in AF.

Conclusion

Our results provide new insights into the molecular mechanisms governing AF progression from the perspective of immune-related ceRNA network.

Plasma levels of BAFF and APRIL are elevated in patients with asthma in Saudi Arabia

B-cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL) are members of the tumor necrosis factor superfamily of cytokines and can induce B cell activation, differentiation, and antibody production via interaction with their receptors, including transmembrane activator, calcium modulator, and cyclophilin ligand interactor (TACI), B-cell maturation antigen (BCMA), and B-cell activating factor receptor (BAFF-R). Herein, we assessed the plasma protein levels of BAFF and APRIL in patients with asthma to determine whether their expression is correlated with total IgE production and examined the surface expression of BAFF/APRIL receptors on B cells. Blood samples were collected from 47 patients with controlled asthma symptoms and 20 healthy normal controls, and plasma levels of APRIL, BAFF, and total IgE protein were quantified by corresponding ELISA assays. Furthermore, lymphocytes were isolated and B cells were analyzed for the presence of BAFF-R, BCMA, and TACI receptors using flow cytometry. Our results showed that IgE, BAFF, and APRIL plasma levels were markedly increased in patients with asthma compared with healthy controls. Moreover, expression of BAFF-R and BCMA, but not that of TACI, was significantly increased in patients with asthma compared with healthy controls. Overall, the findings suggest BAFF and APRIL as key mediators of asthma, and determination of their plasma levels may be useful in monitoring asthma symptoms and treatment response.

Advances in allergen immunotherapy for asthma

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is a well-known disease-modifying intervention for allergic diseases. Its benefit in allergic asthma, ranging from prevention to facilitating asthma control, is yet to be clarified.

RECENT FINDINGS

In 2017, following several well-designed randomised controlled trials (RCTs) with house-dust mites (HDM) sublingual (SLIT) tablets in asthma, global initiative for asthma (GINA) guidelines highlighted the need to treat the allergic component of asthma. In 2019, the European Academy of Allergy and Clinical Immunology published the first comprehensive guidelines for HDM AIT in allergic asthma, formulating separate recommendations for subcutaneous, SLIT drops, and SLIT tablets. Significant steps were undertaken in understanding the mechanisms of allergic asthma, facilitating the stratified approach for selecting responders and in translating the immune-modulation effect in achieving long-term control of the chronic inflammation in asthma.

SUMMARY

Currently existing guidelines recommend AIT as a therapeutic option in controlled or partially controlled HDM allergic asthma. Limited data are available for pollen, molds and pets, as well as for the severe allergic asthma population. The challenge for the future research will be to clarify the subendotypes of allergic asthma responding to AIT, the mechanisms facilitating its' preventive and disease-modifying effect, the optimal duration of the treatment, and route of administration.