The activation of BAFF/APRIL system in spleen and lymph nodes of Plasmodium falciparum infected patients

The impact of Plasmodium-driven immunoregulatory networks on immunity to malaria

Malaria, caused by infection with Plasmodium parasites, drives multiple regulatory responses across the immune landscape. These regulatory responses help to protect against inflammatory disease but may in some situations hamper the acquisition of adaptive immune responses that clear parasites. In addition, the regulatory responses that occur during Plasmodium infection may negatively affect malaria vaccine efficacy in the most at-risk populations. Here, we discuss the specific cellular mechanisms of immunoregulatory networks that develop during malaria, with a focus on knowledge gained from human studies and studies that involve the main malaria parasite to affect humans, Plasmodium falciparum. Leveraging this knowledge may lead to the development of new therapeutic approaches to increase protective immunity to malaria during infection or after vaccination.

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.

Immunomodulatory effects of BAFF and APRIL cytokines in post-pulmonary infection lung cancer: Implications for drug resistance and progression

Lung cancer is a complicated and challenging disease and is one of the most common causes of cancer-related mortality worldwide. Within the lung microenvironment, specific cytokines, including the B cell activation factor (BAFF) and the A proliferation-inducing ligand (APRIL), are produce by various cells, notably airway epithelial cells, in response allergic inflammation or pulmonary infection. These cytokines play a critical role in maintaining local immune responses and fostering the survival of immune cells. The BAFF and APRIL system have been connected in a range of malignancies and have shown their potential in inducing drug resistance and promoting cancer progression. This review highlights recent studies on the involvement of BAFF and APRIL in various cancers, focusing mainly on their role in lung cancer, and discusses the possibility of these molecules in contributing to drug resistance and cancer progression following pulmonary infection. We suggest consideration the targeting BAFF and APRIL or their respective receptors as promising novel therapies for effective treatment of lung cancer, especially post pulmonary infection. However, it remains important to conduct further investigations to fully elucidate the precise mechanisms underlying how the BAFF and APRIL systems enhance cancer survival and drug resistance subsequent pulmonary infections.

A PRoliferation-Inducing Ligand (APRIL) in the Pathogenesis of Immunoglobulin A Nephropathy: A Review of the Evidence

A PRoliferation-Inducing Ligand (APRIL), the thirteenth member of the tumor necrosis factor superfamily, plays a key role in the regulation of activated B cells, the survival of long-lived plasma cells, and immunoglobulin (Ig) isotype class switching. Several lines of evidence have implicated APRIL in the pathogenesis of IgA nephropathy (IgAN). Globally, IgAN is the most common primary glomerulonephritis, and it can progress to end-stage kidney disease; yet, disease-modifying treatments for this condition have historically been lacking. The preliminary data in ongoing clinical trials indicate that APRIL inhibition can reduce proteinuria and slow the rate of kidney disease progression by acting at an upstream level in IgAN pathogenesis. In this review, we examine what is known about the physiologic roles of APRIL and evaluate the experimental and epidemiological evidence describing how these normal biologic processes are thought to be subverted in IgAN. The weight of the preclinical, clinical, and genetic data supporting a key role for APRIL in IgAN has galvanized pharmacologic research, and several anti-APRIL drug candidates have now entered clinical development for IgAN. Herein, we present an overview of the clinical results to date. Finally, we explore where more research and evidence are needed to transform potential therapies into clinical benefits for patients with IgAN.

Distinct binding mode of BAFF antagonist antibodies belimumab and tabalumab, analyzed by computer simulation

B cell-activating factor (BAFF) can bind with specific receptors to activate signalling pathways associated with the B cell activation. Belimumab and tabalumab are anti-BAFF (B cell depleting) monoclonal antibodies, with therapeutic efficacy demonstrated for the treatment of autoimmune disorders, while belimumab was approved by FDA in 2011 as a targeted therapy for systemic lupus erythematosus (SLE) and exhibited better clinical outcome than tabalumab. In this investigation, the combination modes of BAFF-belimumab and BAFF-tabalumab complexes were simulated in silico to better understand the reason for the comparative inhibitory difference between belimumab and tabalumab. The structures of belimumab and tabalumab were constructed through homology modelling. The combination mode of BAFF-belimumab complex was analyzed by molecular dynamics simulation, while that of BAFF-tabalumab complex was analyzed by protein-protein docking following the molecular dynamics simulation. Both belimumab and tabalumab were bound with BAFF at the same hydrophobic center to which the natural receptors of BAFF bind as well. Belimumab heavy chain components I51, F54, K58, D100, D101, L102, L103, and P105 and R27, Y30, K49, and S65 of belimumab light chain contribute to the BAFF-belimumab interaction mainly via hydrogen bonds, salt bridges, and hydrophobic interactions. More importantly, belimumab could bind to L83 of BAFF and produce steric hindrance with the adjacent BAFF trimers, while tabalumab could not. Therefore, our results indicated that belimumab has a better clinical outcome compared with tabalumab mainly because belimumab could bind to L83 of BAFF and interfere the formation of a BAFF 60-mer, besides mediating inhibition of the interaction of BAFF with its receptors.

Immunosuppression in Malaria: Do Plasmodium falciparum Parasites Hijack the Host?

Malaria reflects not only a state of immune activation, but also a state of general immune defect or immunosuppression, of complex etiology that can last longer than the actual episode. Inhabitants of malaria-endemic regions with lifelong exposure to the parasite show an exhausted or immune regulatory profile compared to non- or minimally exposed subjects. Several studies and experiments to identify and characterize the cause of this malaria-related immunosuppression have shown that malaria suppresses humoral and cellular responses to both homologous (Plasmodium) and heterologous antigens (e.g., vaccines). However, neither the underlying mechanisms nor the relative involvement of different types of immune cells in immunosuppression during malaria is well understood. Moreover, the implication of the parasite during the different stages of the modulation of immunity has not been addressed in detail. There is growing evidence of a role of immune regulators and cellular components in malaria that may lead to immunosuppression that needs further research. In this review, we summarize the current evidence on how malaria parasites may directly and indirectly induce immunosuppression and investigate the potential role of specific cell types, effector molecules and other immunoregulatory factors.

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

Allergic asthma, which is the most common type of asthma, is mediated by the IgE response, and B cells are key drivers of allergic inflammation in the lungs. B cell activation factor (BAFF) and proliferation inducing ligand (APRIL) are members of the TNF superfamily. BAFF and APRIL interact with three receptors, namely the B cell activation factor receptor (BAFF-r), B cell maturation antigen (BCMA), and transmembrane activator; calcium modulator; and cyclophilin ligand interactor (TACI). The interaction of BAFF and APRIL with their receptors induces B cell activation, differentiation, and antibody production. BAFF and APRIL are produced by airway epithelial cells during the response to allergens or infectious agents, and have shown to induce local IgE production, thus establishing allergic inflammation in the airways. BAFF can maintain in inflamed airways during infection and can inhibit regulatory T cells (Tregs), thereby promoting allergic inflammation in the airways. This review aims to outline current knowledge about BAFF/APRIL systems in humans as well as in murine models of allergic asthma. The precise role of BAFF and APRIL and their receptors in allergic asthma remains unclear. Therefore, further studies are required to identify and elucidate their roles in enhancing IgE production and activating immune cells that drive the Th2 effector response and initiate allergic inflammation in asthma. Targeting BAFF/APRIL or their cognate receptors may offer a novel therapeutic approach in asthma treatment.