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

A T-cell-independent (TI) pathway activated by microbiota results in the generation of low-affinity homeostatic IgA with a critical role in intestinal homeostasis. Moderate aerobic exercise (MAE) provides a beneficial impact on intestinal immunity, but the action of MAE on TI-IgA generation under senescence conditions is unknown. This study aimed to determine the effects of long-term MAE on TI-IgA production in young (3 month old) BALB/c mice exercised until adulthood (6 months) or aging (24 months). Lamina propria (LP) from the small intestine was obtained to determine B cell and plasma cell sub-populations by flow cytometry and molecular factors related to class switch recombination [Thymic Stromal Lymphopoietin (TSLP), A Proliferation-Inducing Ligand (APRIL), B Cell Activating Factor (BAFF), inducible nitric oxide synthase (iNOS), and retinal dehydrogenase (RDH)] and the synthesis of IgA [α-chain, interleukin (IL)-6, IL-21, and Growth Factor-β (TGF-β)]; and epithelial cells evaluated IgA transitosis [polymeric immunoglobulin receptor (pIgR), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-4] by the RT-qPCR technique. The results were compared with data obtained from sedentary age-matched mice. Statistical analysis was computed with ANOVA, and p < 0.05 was considered to be a statistically significant difference. Under senescence conditions, MAE promoted the B cell and IgA+ B cells and APRIL, which may improve the intestinal response and ameliorate the inflammatory environment associated presumably with the downmodulation of pro-inflammatory mediators involved in the upmodulation of pIgR expression. Data suggested that MAE improved IgA and downmodulate the cytokine pro-inflammatory expression favoring homeostatic conditions in aging.

CONCLUSIONS: Immune dysregulation is thought to contribute to chronic lymphocytic leukemia (CLL) risk, but biological mechanisms are unclear. We discovered that increased serum levels of B-cell activating factor (BAFF), an important regulator of B-cell maturation, were associated with a decreased risk of CLL, even >10 years after blood draw. Our findings suggest that BAFF could be a useful biomarker to assess risk among individuals at high risk, such as those with monoclonal b-cell lymphocytosis.

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.

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.

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.

BACKGROUND: The long-term use of rituximab (RTX) has been gaining ground in the treatment of systemic autoimmune diseases. The adverse events (AEs) associated with its use different to infections are being reported.
METHODS: A cohort of patients with SAIDs treated at a high-complexity center in Cali (southwestern Colombia) with follow-up from January 2008 to December 2022 were examined to search for potential AEs associated with prolonged use of RTX.
RESULTS: From 178 patients with long-term use of RTX 3 (1.68%) had lymphadenopathies with lymphoid follicular hyperplasia related to BAFF overexpression, 4 (2.24%) with bronchiectasis, and 4 (2.24%) with lymphoplasmacytic cystitis.
CONCLUSIONS: Bronchiectasis, lymphoid follicular hyperplasia related to BAFF overexpression, and lymphoplasmacytic cystitis may be life-threatening long-term AEs in patients with prolonged use of RTX.

Chronic kidney disease (CKD) is an emerging cause for morbidity and mortality worldwide. Acute kidney injury (AKI) can transition to CKD and finally to end-stage renal disease (ESRD). Targeted treatment is still unavailable. NF-κB signaling is associated with CKD and activated by B cell activating factor (BAFF) via BAFF-R binding. In turn, renal tubular epithelial cells (TECs) are critical for the progression of fibrosis and producing BAFF. Therefore, the direct involvement of the BAFF/BAFF-R system to the pathogenesis of CKD is conceivable. We performed non-accelerated nephrotoxic serum nephritis (NTN) as the CKD model in BAFF KO (B6.129S2-Tnfsf13btm1Msc/J), BAFF-R KO (B6(Cg)-Tnfrsf13ctm1Mass/J) and wildtype (C57BL/6J) mice to analyze the BAFF/BAFF-R system in anti-glomerular basement membrane (GBM) disease using high throughput RNA sequencing. We found that BAFF signaling is directly involved in the upregulation of collagen III as BAFF ko mice showed a reduced expression. However, these effects were not mediated via BAFF-R. We identified several upregulated genes that could explain the effects of BAFF in chronic kidney injury such as Txnip, Gpx3, Igfbp7, Ccn2, Kap, Umod and Ren1. Thus, we conclude that targeted treatment with anti-BAFF drugs such as belimumab may reduce chronic kidney damage. Furthermore, upregulated genes may be useful prognostic CKD biomarkers.

The treatment of HCV and its sequelae are used to be predominantly based on Interferon (IFN). However, this was associated with significant adverse events as a result of its immunostimulant capabilities. Since their introduction, the directly acting antiviral drugs (DAAs), have become the standard of care to treat of HCV and its complications including mixed cryoglobulinemic vasculitis (MCV). In spite of achieving sustained viral response (SVR), there appeared many reports describing unwelcome complications such as hepatocellular and hematological malignancies as well as relapses. Prolonged inflammation induced by a multitude of factors, can lead to DNA damage and affects BAFF and APRIL, which serve as markers of B-cell proliferation. We compared, head-to-head, three antiviral protocols for HCV-MCV treatment As regards the treatment response and relapse, levels of BAFF and APRIL among pegylated interferon α-based and free regimens (Sofosbuvir + Ribavirin; SOF-RIBA, Sofosbuvir + Daclatasvir; SOF-DACLA). Regarding clinical response HCV-MCV and SVR; no significant differences could be identified among the 3 different treatment protocols, and this was also independent form using IFN. We found no significant differences between IFN-based and free regimens DNA damage, markers of DNA repair, or levels of BAFF and APRIL. However, individualized drug-to-drug comparisons showed many differences. Those who were treated with IFN-based protocol showed decreased levels of DNA damage, while the other two IFN-free groups showed increased DNA damage, being the worst in SOF-DACLA group. There were increased levels of BAFF through follow-up periods in the 3 protocols being the best in SOF-DACLA group (decreased at 24 weeks). In SOF-RIBA, CGs relapsed significantly during the follow-up period. None of our patients who were treated with IFN-based protocol had significant clinico-laboratory relapse. Those who received IFN-free DAAs showed a statistically significant relapse of constitutional manifestations. Our findings suggest that IFN-based protocols are effective in treating HCV-MCV similar to IFN-free protocols. They showed lower levels of DNA damage and repair. We believe that our findings may offer an explanation for the process of lymphoproliferation, occurrence of malignancies, and relapses by shedding light on such possible mechanisms.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is a potentially life-threatening complication among Multiple Sclerosis (MS) patients under natalizumab treatment, with serum anti-JCV antibody titers being used for stratification risk. Given the critical role of interferon (IFN)/B-cell activating factor (BAFF) axis in humoral immune responses against viruses, we explored whether it is involved in the generation of serum anti-JCV antibodies among these patients.
METHODS: 162 consecutive patients with relapsing-remitting MS under natalizumab treatment were included. Serum anti-JCV antibodies were measured at baseline, as well as 12 and 24 months after treatment initiation. Type I and II IFN-inducible genes and BAFF expression were quantitated in peripheral blood by qRT-PCR. Moreover, BAFF rs9514828, rs1041569, and rs9514827 gene variants were assessed by RFLP-PCR.
RESULTS: While type I and II IFN inducible gene expression were not associated with anti-JCV serum titers, the latter were significantly correlated with BAFF gene expression. Of interest, the TTT haplotype of the studied BAFF variants was more frequently detected in male, but not female anti-JCV (+) MS patients compared to anti-JCV (-) counterparts at baseline, as well as at 12 months and 24 months of natalizumab treatment. Measures of clinical validity/utility for the BAFF TTT haplotype showed 88% specificity, 45%, positive predictive value, and sensitivity of 70% for the discrimination of anti-JCV (+) male MS patients after 24 months of treatment.
CONCLUSIONS: Our study suggests an implication of the BAFF axis in the production of serum anti-JCV antibodies. Additionally, the BAFF TTT haplotype derived from the rs9514828, rs1041569, and rs9514827 variants may represent a novel risk factor for anti-JCV seropositivity and indirectly for PML development among male MS patients treated with natalizumab.