Project description:Primary membranous nephropathy (MN) is a kidney-specific autoimmune glomerular disease and the leading cause of nephrotic syndrome (NS) in White adults, usually caused by antiphospholipase A2 receptor (PLA2R) antibodies, although several new target antigens have been recently identified. It is characterized by the diffuse thickening of the glomerular basement membrane secondary to immune complex deposition. In patients with persistent NS without response to maximizing conservative therapy including the use of renin-angiotensin system (RAS) blockers, the use of immunosuppressive agents is warranted. However, the optimal immunosuppressive treatment has not yet been established. Classical immunosuppressants, such as cyclophosphamide plus steroids, are effective but may cause clinically relevant adverse effects, limiting their use. Rituximab offers efficacy with a better safety profile whereas calcineurin inhibitors (CNIs) are marred by high relapse rates and nephrotoxicity. Nevertheless, up to 30% of patients fail to respond to standard therapy. Novel and specific therapies targeting B cells and plasma cells have shown encouraging preliminary results, in terms of clinical efficacy and safety profile, especially in patients with poor tolerance or refractory to conventional treatments. In this brief review, we discuss the benefits and limitations of the current therapeutic approach to MN and describe emerging novel therapies that target its pathogenesis.
Project description:Membranous nephropathy (MN) is an autoimmune disease of the kidney glomerulus, which mainly leads to nephrotic syndrome. This study investigates the associations between air pollution and MN risk and from an epigenomic perspective. In this study, we examine the associations between genetically predicted deoxyribonucleic acid methylation related to air pollution and MN risk. The data of air pollution included particulate matter (PM) with a diameter of 2.5 µm or less (PM2.5), PM with a diameter between 2.5 and 10 µm (PM2.5-10), PM with a diameter of 10 µm or less (PM10), nitrogen dioxide, and nitrogen oxides. Inverse variance weighted method was used as the main analysis method, and weighted median model and Mendelian randomization-Egger methods were selected for quality control. To assess the reliability of the results of the analyses, heterogeneity test, horizontal pleiotropy test, and the leave-one-out method were applied. There was a causal relationship between nitrogen oxides and MN risk (P = .010). Other types of air pollution were found no statistical association with MN disease (PM2.5: P = .378; PM2.5-10: P = .111; PM10: P = .035; nitrogen dioxide: P = .094). There was no heterogeneity or pleiotropy in the results. Our study suggests the association between nitrogen oxides and membrane nephropathy (MN) risk from the genetic perspective. This provides a theoretical basis for the prevention of MN disease.
Project description:Primary membranous nephropathy (PMN) is one of the common causes of adult-onset nephrotic syndrome and is characterized by autoantibodies against podocyte antigens causing in situ immune complex deposition. Much of our understanding of the disease mechanisms underpinning this kidney-limited autoimmune disease originally came from studies of Heymann nephritis, a rat model of PMN, where autoantibodies against megalin produced a similar disease phenotype though megalin is not implicated in human disease. In PMN, the major target antigen was identified to be M-type phospholipase A2 receptor 1 (PLA2R) in 2009. Further utilization of mass spectrometry on immunoprecipitated glomerular extracts and laser micro dissected glomeruli has allowed the rapid discovery of other antigens (thrombospondin type-1 domain-containing protein 7A, neural epidermal growth factor-like 1 protein, semaphorin 3B, protocadherin 7, high temperature requirement A serine peptidase 1, netrin G1) targeted by autoantibodies in PMN. Despite these major advances in our understanding of the pathophysiology of PMN, treatments remain non-specific, often ineffective, or toxic. In this review, we summarize our current understanding of the immune mechanisms driving PMN from animal models and clinical studies, and the implications on the development of future targeted therapeutic strategies.
Project description:Many prospective studies and a recent randomized controlled trial have shown that the B-cell-depleting monoclonal antibody, rituximab, safely promotes the remission of nephrotic syndrome in approximately 65% of patients with membranous nephropathy (MN). Mechanistic studies have indicated that rituximab-induced proteinuria reduction is associated with clearance of anti-podocyte antigens phospholipase 2 receptor autoantibodies and subepithelial immune complexes, the hallmarks of the disease. A recently published study reported results which, at first sight, looked less favorable and implied that, due to a publication bias against negative results, the efficacy of rituximab in MN might be overestimated. Since patients received only one or 2 rituximab administrations, the authors suggest that when rituximab is used, higher doses and longer treatments should be considered. In this study, we highlight limitations of the study and warn against an oversimplified interpretation of the data. Though information on the optimal dose of rituximab to use in MN is still limited, available data from studies with predefined rituximab administration protocols collectively support the concept of titrating rituximab to the number of circulating B-cells that are invariably depleted after the first or second administration. Additional doses may increase the risk of adverse effects and related costs without augmenting efficacy. Importantly, underpowered studies with inconclusive results should not be confused with negative studies formally proving a neutral effect of a treatment. Until data from ad hoc designed clinical trials are available, the B-cell-driven protocol should be the preferred regimen, since it is similarly effective, but safer and more cost effective than other protocols employing multiple rituximab administrations.
Project description:IgA Nephropathy (IgAN) and Membranous Nephropathy (MN) are primary immune-mediated glomerular diseases with highly variable prognosis. Current guidelines recommend that greater immunologic activity and worse prognosis should guide towards the best treatment in an individualized approach. Nevertheless, proteinuria and glomerular filtration rate, the current gold standards for prognosis assessment and treatment guidance in primary glomerular diseases, may be altered with chronic damage and nephron scarring, conditions that are not related to immune activity. In recent years, thanks to the development of new molecular technologies, among them genome-wide genotyping, RNA sequencing techniques, and mass spectrometry, we have witnessed an outstanding improvement in understanding the pathogenesis of IgAN and MN. In addition, recent genome-wide association studies have suggested potential targets for immunomodulating agents, stressing the need for the identification of specific biomarkers of immune activity. In this work, we aim to review current evidence and recent progress, including the more recent use of omics techniques, in the identification of potential biomarkers for immune monitoring in IgAN and MN.
Project description:An HLA-DR3 association with membranous nephropathy (MN) was described in 1979 and additional evidence for a genetic component to MN was suggested in 1984 in reports of familial MN. In 2009, a pathogenic autoantibody was identified against the phospholipase A2 receptor 1 (PLA2R1). Here we discuss the genetic studies that have proven the association of human leucocyte antigen class II and PLA2R1 variants and disease in MN. The common variants in PLA2R1 form a haplotype that is associated with disease incidence. The combination of the variants in both genes significantly increases the risk of disease by 78.5-fold. There are important genetic ethnic differences in MN. Disease outcome is difficult to predict and attempts to correlate the genetic association to outcome have so far not been helpful in a reproducible manner. The role of genetic variants may not only extend beyond the risk of disease development, but can also help us understand the underlying molecular biology of the PLA2R1 and its resultant pathogenicity. The genetic variants identified thus far have an association with disease and could therefore become useful biomarkers to stratify disease risk, as well as possibly identifying novel drug targets in the near future.
Project description:Membranous nephropathy (MN) is the most common cause of primary nephrotic syndrome among adults. The identification of phospholipase A2 receptor (PLA2R) as target antigen in most patients changed the management of MN dramatically, and provided a rationale for B-cell depleting agents such as rituximab. The efficacy of rituximab in inducing remission has been investigated in several studies, including 3 randomized controlled trials, in which complete and partial remission of proteinuria was achieved in approximately two-thirds of treated patients. Due to its favorable safety profile, rituximab is now considered a first-line treatment option for MN, especially in patients at moderate and high risk of deterioration in kidney function. However, questions remain about how to best use rituximab, including the optimal dosing regimen, a potential need for maintenance therapy, and assessment of long-term safety and efficacy outcomes. In this review, we provide an overview of the current literature and discuss both strengths and limitations of "the new standard."