Membranous nephropathy

Treatment of nephrotic syndrome with anti-CD20 therapies in pregnancy: a case series and review of the literature

Membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) are autoimmune kidney diseases and the most common causes of nephrotic syndrome. Anti-CD20 monoclonal antibodies are now recommended as first-line therapy for MN. Anti-CD20 monoclonal antibodies are also effective in steroid-dependent or frequently relapsing nephrotic syndrome associated with MCD or FSGS. Many women eligible for these treatments are of childbearing age. The impact of anti-CD20 therapies on pregnancy and fetal outcomes remains uncertain, particularly in glomerular diseases. We describe three cases of patients with glomerular disease treated with anti-CD20 therapies in the context of pregnancy and review the literature.

Causal associations between environmental factors and risk of IgA nephropathy and membranous nephropathy: a bidirectional Mendelian randomization and mediation analysis

AIMS

IgA nephropathy (IgAN) and membranous nephropathy (MN) have intricate etiologies that are poorly understood. This study aimed to investigate the impact of genetically predicted environmental factors on IgAN and MN.

METHODS

We used bidirectional two-step Mendelian randomization (MR) analysis utilizing large-scale genome-wide association study (GWAS) data to investigate the relationships between 68 environmental exposures and IgAN and MN. The main method is inverse variance weighted (IVW). Sensitivity analyses were conducted to validate the causal estimates. Furthermore, the two-step MR was used to explore possible mediating effects.

RESULTS

A total of 20 significant causal associations were identified. Genetically predicted educational attainment (EA), average household income, gluten-free diet, cheese intake, fresh fruit intake, cognitive performance, and intelligence were associated with a reduced risk of IgAN (p < 0.05); whereas frequency of alcohol consumption, insomnia, triglycerides, transferrin saturation, percentage body fat, body mass index (BMI), waist circumference, and blood pressure were associated with the risk of IgAN (p < 0.05). Genetically predicted EA and moderate to vigorous physical activity were associated with a reduced risk of MN (p < 0.05); on the other hand, beef intake, waist-to-hip ratio, and nitrogen oxides were associated with the risk of MN (p < 0.05). In addition, we observed that insomnia, BMI, and waist circumference partially mediated the causal link between EA and IgAN, with mediation proportions of 12.52%, 11.06%, and 9.93%, respectively.

CONCLUSIONS

This study provides novel evidence of causal relationships between 20 genetically predicted environmental factors and the risk of IgAN and MN. These findings may inform targeted prevention strategies and contribute to improved disease risk assessment.

Exploring the causal role of pathogen-derived antibodies in major urinary and kidney diseases: Insights from generalized summary data-based Mendelian randomization

Chronic kidney and urinary tract diseases, including glomerulonephritis, nephrotic syndrome, and chronic kidney disease (CKD), present significant global health challenges. Recent studies suggest a complex interplay between infectious pathogens and immune-mediated kidney damage. This study employs Generalized Summary data-based Mendelian Randomization (GSMR) to explore causal relationships between pathogen-derived antibodies and major urinary and kidney diseases.We conducted a two-sample MR analysis using summary statistics from large-scale Genome-Wide Association Studies (GWAS) to assess associations between 46 pathogen-specific antibodies and seven urinary system diseases. We utilized robust statistical methods, including inverse variance weighting, to ascertain causal effects while controlling for potential confounders.Significant associations were identified between several pathogen-specific antibodies and disease risk. Notably, Epstein-Barr virus (EBNA-1) antibody levels were inversely associated with glomerulonephritis and nephrotic syndrome, indicating a potential protective effect. Conversely, Anti-Merkel cell polyomavirus IgG seropositivity was linked to increased risks of CKD and glomerulonephritis. Additionally, immune-mediated mechanisms were highlighted, with certain antibodies exhibiting dual roles as risk factors or protective agents.This study underscores the complex role of pathogen antibodies in the pathogenesis of kidney and urinary tract diseases, revealing significant implications for future research and potential therapeutic strategies. The findings advocate for further investigation into specific pathogen interactions with the immune system, aiming to inform targeted interventions.

Autoantibodies and therapeutic antibodies against complement factor H

The complement system is a crucial part of our immune defense as, upon recognition, it can kill pathogens fast and effectively. However, misguided complement activation could cause damage to host tissues. Therefore, a well-controlled regulation of the complement system is a necessity to prevent collateral damage. Regulation is achieved by several complement inhibitory proteins, acting at different levels of the complement system. One of these complement regulators is factor H, the main regulator of the alternative complement activation pathway. Factor H can regulate the complement system both in fluid-phase and on the host cell surface by, for example, acting as co-factor for factor I, inactivating C3b. The functional properties of factor H are located within different regions of the protein. Functional impairment of factor H, either because of genetic variants, competing proteins such as the factor H-related proteins and proteins from certain pathogens, but also the presence of autoantibodies will impact on complement activation. However, exact consequences are dependent on the region within factor H that is affected. Autoantibodies binding to factor H have been shown to inhibit several regulatory functions of factor H, which is observed in diseases such as membranoproliferative glomerulonephritis and atypical hemolytic uremic syndrome. As more recently the presence of anti-factor H autoantibodies has also been discovered in several other diseases, ranging from autoimmune diseases to cancer, this review provides an overview of the presence of factor H autoantibodies described in these diseases. Factor H autoantibodies are reported to have inhibitory, or enhancing, effects on factor H, depending on the epitopes that are recognized. Formal conclusions about the pathogenicity of the factor H autoantibodies in some of these diseases cannot be drawn yet. Importantly, understanding the binding and functional impact of anti-factor H (auto)antibodies will allow targeted interventions to diminish pathological consequences of anti-factor H autoantibodies but may also open up additional avenues for the use of anti-factor H antibodies as therapeutic agents.

Complement-coagulation crosstalk in idiopathic membranous nephropathy: The potential pathogenesis and therapeutic perspective

Idiopathic membranous nephropathy (IMN) is a glomerular disease that is prevalent in elderly males. The pathogenesis of IMN includes abnormal autoimmunity and complement activation, both of which leading to the damage of the glomerular filtration structure. Meanwhile, due to the pathological changes in the kidney, certain coagulation-related proteins are leaked from urine, resulting in the imbalance of coagulation homeostasis. Recent studies have indicated the interaction between complement and coagulation systems, while the aberration of both is common in IMN. In this review, we summarize the subsistent and underlying pathogenesis that ensue from complement-coagulation crosstalk and present the emerging evidence in this evolving field.

Migrasomes as intercellular messengers: potential in the pathological mechanism, diagnosis and treatment of clinical diseases

Migrasomes are newly identified organelles that were first discovered in 2015. Since then, their biological structure, formation process, and physiological functions have been gradually elucidated. Research in recent years has expanded our understanding of these aspects, highlighting their significance in various physiological and pathological processes. Migrasomes have been found to play crucial roles in normal physiological functions, including embryonic development, vascular homeostasis, material transport, and mitochondrial quality control. Additionally, emerging evidence suggests their involvement in various diseases; however, clinical research on their roles remains limited. Current studies indicate that migrasomes may contribute to disease pathogenesis and hold potential for diagnostic and therapeutic applications. This review consolidates existing clinical research on migrasomes, focusing on their role in disease mechanisms and their use in medical applications. By examining their biological structure and function, this review aims to generate insights that encourage further research, ultimately contributing to advancements in disease prevention and treatment.

The PM2.5 component, benzo[b]fluoranthene, may contribute to the pathogenesis of membranous nephropathy by activating phosphoinositide 3-kinase/protein kinase B pathway and causing podocyte pyroptosis

Membranous nephropathy (MN) is the main type of adult nephrotic syndrome, and its prevalence is increasing annually. An increasing number of studies have suggested that the pathogenesis of MN is related to 2.5-μm particulate matter (PM2.5), but the underlying mechanism has not been elucidated fully. Elucidating this mechanism can help prevent and treat MN. The constituents of PM2.5 vary from place to place; hence, the component responsible for PM2.5-related MN is still unclear. This study investigated the effects of benzo[b]fluoranthene (BbF), a PM2.5 component, on pyroptosis and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signalling pathway in Sprague-Dawley rats and mouse podocytes. The organic constituents of BbF in PM2.5 can enter the circulatory system through the lungs and act on the kidneys to cause kidney damage, possibly because BbF activates the PI3K/AKT pathway and causes podocytes to undergo pyroptosis.

Decoding B Cells in Autoimmune Diseases Through ScRNA + BCR-Seq: Current Knowledge and Future Directions

The combined application of single-cell RNA sequencing (scRNA-seq) and single-cell B-cell receptor sequencing (scBCR-seq) offers a multidimensional perspective for dissecting the immunopathological mechanisms of B cells in autoimmune diseases. This review systematically summarizes the principles of these techniques, the analytical framework, and their key applications in diseases such as systemic lupus erythematosus et. al. It reveals the dynamic correlations between the transcriptome of B-cell subsets and B-cell receptor (BCR) clones. Furthermore, we focus on the potential roles of dual BCR B cells and B/T biphenotypic cells in autoimmunity, emphasizing their exacerbation of disease progression through abnormal clonal expansion and autoantibody secretion. By sorting through cutting-edge advancements and bottleneck issues, this article aims to propel the innovation of multi-omics research and precision treatment paradigms for autoimmune diseases.

Tiopronin-induced Membranous Nephropathy Presenting with IgG4-predominant Staining Pattern

Tiopronin is a key drug used to treat cystinuria. A 41-year-old Japanese woman with cystinuria presented with eyelid edema and weight gain after the administration of tiopronin. Her serum albumin was 1.8 g/dL and her urinary protein level was 5.5 g/gCre. After cessation of tiopronin, she achieved remission of nephrotic syndrome (NS). Secondary NS due to tiopronin was evident based on the clinical course and laboratory values. A kidney biopsy showed membranous nephropathy (MN), and an immunofluorescence analysis revealed strong deposition of immunoglobulin G4 (IgG4). However, a previous case report of tiopronin-induced MN showed staining for IgG1 and IgG3. This case report suggests a novel etiology for tiopronin-induced MN.

Efficacy and safety of ripertamab for treating primary membranous nephropathy among adults: a multicenter, retrospective, real-world study

Background

Ripertamab has been used in an off-label manner for treating primary membranous nephropathy (PMN) in real-world settings in China, despite limited evidence supporting the efficacy of this drug. This multicenter, retrospective study is the first to assess the effectiveness and safety of ripertamab for treating PMN in a real-world Chinese clinical setting.

Methods

Adult patients with PMN who were treated with at least one course of ripertamab alone were included in this study. Patients were categorized into two groups based on their prior treatment of PMN: the initial therapy group and the non-initial therapy group. The primary outcome was the occurrence of complete remission (CR) or partial remission (PR) at 6 and 12 months. The secondary outcomes included the time to achieve remission, relapse rate and the incidence of adverse events (AEs).

Results

Fifty-two patients were ultimately included for analysis. Among these patients, 39 received ripertamab as initial therapy, while 13 were in the non-initial therapy group. The median follow-up duration was 8.7 (4.7, 11.3) months. At 6 months, 24/40 (60.0%) patients achieved clinical remission, with 2/40 (5.0%) achieving CR and 22/40 (55.0%) achieving PR. At 12 months, 22 patients completed follow-up: 2 (9.1%) achieved CR, and 15 (68.2%) achieved PR. The median time to remission for the entire cohort was 90.5 (32, 165) days and four of the 52 patients (7.7%) relapsed. The initial therapy group had a higher remission rate at 12 months than the non-initial therapy group [13/15 (86.7%) vs. 4/7 (57.1%)]. Additionally, the initial therapy group achieved remission more quickly than the non-initial therapy group [79.0 (36, 112) vs. 165.0 (30, 313) days]. Ripertamab was well tolerated, with 9.6% (5/52) of patients experiencing AEs; none of the AEs were severe.

Conclusion

Ripertamab demonstrated efficacy and good tolerability for the treatment of PMN in a Chinese real-world setting. These findings support the use of ripertamab as a therapeutic option for PMN patients and suggest the need for further investigation into its long-term safety and efficacy.

Comparison of B lymphocyte profile between membranous nephropathy and idiopathic nephrotic syndrome pediatric patients

BACKGROUND

Membranous nephropathy (MN) and idiopathic nephrotic syndrome (INS) are two B-cell mediated rare glomerular diseases that benefit from treatment with B-cell depleting anti-CD20 monoclonal antibody rituximab. Different B-cell dysregulations have been described in pediatric INS patients and in adults affected by MN. In adult MN patients, an increased level of mature-naïve cells and atypical memory B cells and a significant reduction in IgM memory and switched memory B cells have been previously described compared to healthy individuals. To date, there is no information available about B-cell immunophenotyping in pediatric MN.

METHODS

In this monocentric retrospective case-control study, we analyzed by flow cytometry the B-cell profile in rituximab-naïve (n = 15) children affected by MN, compared with pediatric INS patients (n = 15) selected by propensity score matching, and both evaluated during active disease. Age-matched controls (n = 15) with non-immune-mediated kidney diseases were also characterized. Demographical, clinical, laboratory, and immunosuppressive treatment data were registered.

RESULTS

We found that children with MN and INS had significantly higher circulating levels of total CD19+, mature-naïve, and atypical memory B cells and similar levels of transitional B cells when compared to age-matched controls. Circulating levels of total memory B cells, IgM memory B cells, and plasmablasts/plasmacells were significantly higher in INS patients compared to both MN patients and age-matched controls.

CONCLUSIONS

Our study indicated that children affected by MN had a specific B-cell profile and that high levels of memory B-cell subsets are specific to INS pediatric patients independently of proteinuria intensity.

Impact of immune cell metabolism on membranous nephropathy and prospective therapy

Membranous nephropathy (MN) is a primary glomerular disease commonly causing adult nephrotic syndrome. Characterized by thickened glomerular capillary walls due to immune complex deposition, MN is a complex autoimmune disorder. Its pathogenesis involves immune deposit formation, complement activation, and a heightened risk of renal failure. Central to MN is immune system dysfunction, particularly the dysregulation of B and T cell responses. B cells contribute to renal injury through the production of autoantibodies, particularly IgG targeting the phospholipase A2 receptor (PLA2R) on podocytes, while T cells modulate immune responses that influence disease progression. Metabolic reprogramming alters lymphocyte survival, differentiation, proliferation, and function, potentially triggering autoimmune processes. Although the link between immune cell metabolism and MN remains underexplored, this review highlights recent advances in understanding immune metabolism and its role in MN. These insights may provide novel biomarkers and therapeutic strategies for MN treatment.

Causal relationships between immune cell phenotypes and primary glomerular diseases: genetic evidence from bidirectional Mendelian randomization study

Background

Primary glomerular diseases (PGDs), including nephrotic syndrome (NS), membranous nephropathy (MN), and IgA nephropathy (IgAN), are complex renal conditions influenced by immune system dysregulation. Although associations between immune cell phenotypes and PGDs have been observed, the precise causal relationships have not been fully elucidated.

Methods

Utilizing genetic association data from genome-wide association studies (GWASs), we investigated 731 immunophenotypes in relation to PGDs. A bidirectional two-sample Mendelian randomization (MR) approach, primarily employing inverse variance weighting (IVW), was conducted to establish causality. MR-Egger, weighted median, simple mode, and weighted mode were used as complementary methods to reinforce the robustness and validity of the results. Sensitivity analyses further validated the sensitivity and stability of our results.

Results

We identified 38 immunophenotypes suggestively related to IgAN, with 20 as risk factors and 18 as protective effects. Six immunophenotypes remained significant after Bonferroni correction: The percentage of CD25hi among T cells; the percentage of CD25hi CD45RA- CD4 not T regulatory (Treg) among T cells; the percentage of CD25hi CD45RA- CD4 not Treg within the CD4+ T cell population; CX3CR1 expression on monocytes; CD40 expression on monocytes; and CD64 expression on CD14+ CD16- monocytes. In the validation analysis of IgAN, CD3 expression on effector memory CD4+ T cells further confirmed the predisposing risk role of effector memory T cells in the development of IgAN. Additionally, the MR analysis demonstrated suggestive associations between 25 immunophenotypes and MN (8 risk factors and 17 protective factors), as well as between 22 immunophenotypes and NS (10 risk factors and 12 protective factors). Last, by intersecting the immunophenotypes showing suggestive associations with PGDs, we identified two common immunophenotypes shared by IgAN and MN, three by IgAN and NS, and one by MN and NS.

Conclusions

This genetic-level investigation uncovers causal associations between immunophenotypes and PGDs, providing valuable insights into the immunological underpinnings of PGDs. Our findings suggest potential targets for treatment strategies, thereby facilitating more personalized and effective therapeutic approaches in PGDs management.

Analysis of survival among biopsy-determined categories of kidney disease in dogs

BACKGROUND

There are many causes of kidney disease in dogs. The association of the diagnostic category with survival is unknown.

OBJECTIVE

Determine survival outcomes for biopsy-determined diagnostic categories of kidney disease in dogs.

ANIMALS

Six hundred forty-nine dogs were biopsied for evaluation of kidney disease.

METHODS

Retrospective study. Survival information was obtained for dogs whose kidney biopsy was submitted to the International Veterinary Renal Pathology Service between 2008 and 2018. Signalment, serum creatinine (sCr), urine protein : creatinine ratio (UPCR), and serum albumin (sAlb) were reported at the time of biopsy. Cox proportional hazards analysis was performed for the 14 categories with >10 cases having follow-up to determine hazard ratios (HR), using focal segmental glomerulosclerosis (FSGS) as baseline.

RESULTS

The median survival time (MST) for all dogs with follow-up (n = 649) was 608 days (interquartile range [IQR]: 109-1475 days). The most follow-up was obtained for FSGS (n = 138, MST 536 days). Dogs with renal amyloidosis (n = 80) had the shortest survival (MST 76 days, IQR 8-299 days) and, in the multivariate analysis including age, sCr, sAlb, and UPCR, an increased risk of death (HR 1.79 [95% CI: 1.22-2.65], P < .01). Dogs with podocytopathy, membranous glomerulonephritis (MGN), mixed MGN, membranoproliferative GN (MPGN), and mixed MPGN had decreased risk of death. Regardless of category, increasing age, sCr, and UPCR and decreased sAlb were associated with a greater risk of death.

CONCLUSIONS

The diagnostic category is associated with survival in dogs with kidney disease. Survival of individual dogs within each category was highly variable.

Clinicopathological features and predictors of anti-GBM disease combined with membranous nephropathy

Background

Anti-glomerular basement membrane (anti-GBM) disease is a rare and life-threatening form of small vessel vasculitis that primarily affects the kidneys and lungs. In rare cases, it occurs with membranous nephropathy (MN). This study aimed to investigate the clinical manifestations, pathological features, prognosis and predictors of anti-GBM disease with MN.

Methods

We enrolled 24 patients with combined anti-GBM disease and MN, and 69 patients with classic anti-GBM disease (without MN). We compared the clinical and pathological differences, as well as the prognoses between the two groups and attempted to identify predictors of anti-GBM disease combined with MN.

Results

A greater proportion of patients with combined disease were male, had a history of smoking, and had nephrotic syndrome (NS). Compared with patients with classic anti-GBM disease, those with anti-GBM disease with MN presented improved renal function, higher hemoglobin and serum C3 levels, and significantly improved renal outcomes (P < .05). In 16 out of 24 double-positive patients, a lower proportion of glomerular crescents and a higher rate of immunoglobulin G4 positivity were observed compared with only 20 of the 69 patients with classic anti-GBM disease confirmed by renal biopsy (P < .05). Furthermore, smoking status, hemoglobin levels and low-density lipoprotein levels were identified as factors associated with the development of anti-GBM combined with MN, potentially serving as predictors.

Conclusions

This study provides insights into the distinct clinical and pathological characteristics of anti-GBM disease with MN. The identification of predictors may contribute to the early recognition and management of these patients.

Immune Imbalance in Primary Membranous Nephropathy at Single-cell Resolution

BACKGROUND

Primary membranous nephropathy (pMN) often progresses to end-stage renal disease (ESRD) in the absence of immunosuppressive therapy. The immunological mechanisms driving pMN progression remain insufficiently understood.

METHODS

We developed a single-cell transcriptomic profile of peripheral blood mononuclear cells (PBMCs) from 11 newly-diagnosed pMN patients and 5 healthy donors. Through correlation analysis, we identified potential biomarkers for disease stratification and poor prognosis.

RESULTS

Expression levels of several proinflammatory factors were significantly increased in patients compared to healthy donors, such as interleukins (IL1B, IL8, and IL15) and interferon G (IFNG). Multiple pattern recognition receptors involved in proinflammatory signaling were also upregulated in patients, including NOD-like receptors (NLRs) (NLRP1, NLRP3, and NLRC5), RNA helicases (DDX58, IFIH1, DHX9, and DHX36), cGAS (cyclic GMP-AMP synthase) and IFI16 (interferon gamma inducible protein 16). Additionally, human leukocyte antigen molecules HLA-DQA1 and HLA-DRB1 enriched in memory B cells were upregulated in patients. More importantly, we found that the genes for antiviral defense response were significantly elevated in high-risk patients relative to the low-risk group. More than twenty genes were negatively correlated with estimated glomerular filtration rate (eGFR), such as BST2 (bone marrow stromal cell antigen 2) and SLC35F1 (solute carrier family 35 member F1). Their predicted values were confirmed in a larger population with nephrotic syndrome or other chronic kidney diseases from a public database. Furthermore, we developed a series of scoring systems for distinguishing high-risk patients from low- and moderate-risk individuals.

CONCLUSIONS

Our study provides insight into the immunological mechanism of pMN and identifies numerous biomarkers and signaling pathways as potential therapeutic targets for managing the progression of high-risk pMN.

Membranous Nephropathy Target Antigens Display Podocyte-Specific and Non-Specific Expression in Healthy Kidneys

BACKGROUND/OBJECTIVES

Autoimmunity towards podocyte antigens causes membranous nephropathy (MN). Numerous MN target antigens (MNTAgs) have been reported, including PLA2R1, THSD7A, NTNG1, TGFBR3, HTRA1, NDNF, SEMA3B, FAT1, EXT1, CNTN1, NELL1, PCDH7, EXT2, PCSK6, and NCAM1, but their podocyte expression has not been thoroughly studied.

METHODS

We screened CZ CELLxGene single-cell RNA (scRNA) sequence datasets for those of adult, fetal, and mouse kidneys and analyzed the above MNTAgs' expression.

RESULTS

In adult kidneys, most MNTAgs are present in podocytes, except PCSK6 and NCAM1. PLA2R1 is expressed significantly more than other MNTAgs in podocytes and is a major podocyte marker, consistent with PLA2R1 as the dominant MNTAg. Additionally, PLA2R1 is a top-upregulated gene in the podocytes of chronic kidney disease, acute kidney injury, and diabetic nephropathy, indicating its general role in causing podocyte injury. PLA2R1, NTNG1, HTRA1, and NDNF display podocyte-enriched expression along with elevated chromatin accessibility in podocytes, suggesting transcription initiation contributing to their preference expression in podocytes. In the fetal kidney, most MNTAgs are expressed in podocytes. While PLA2R1 is weakly present in podocytes, SEMA3B is abundantly expressed in immature and mature podocytes, supporting SEMA3B as a childhood MNTAg. In mouse kidneys, Thsd7a is the only MNTAg with a prominent level and podocyte-specific expression. Conclusions: Most MNTAgs are present in podocytes in adults and during renal development. In adults, PLA2R1 expression is highly enriched in podocytes and significantly upregulated in multiple kidney diseases accompanied by proteinuria. In mouse kidneys, Thsd7a is specifically expressed in podocytes at an elevated level.

Is there a place for engineered immune cell therapies in autoimmune diseases?

The ability to engineer immune cells yielded a transformative era in oncology. Early clinical trials demonstrated the efficacy of chimeric antigen receptor (CAR) T cells in resetting the immune system, motivating the expansion of this treatment beyond cancer, including autoimmune conditions. In this review, we discuss the current state of CAR T cell research in autoimmune diseases, examining the main challenges that limit widespread adoption of this therapy, such as complex isolation protocols, stringent immunosuppression, risk of secondary malignancies, and variable efficacy. We also review the studies addressing these limitations by development of off-the-shelf allogeneic CAR T cells, tunable safety systems, and antigen-specific therapies, which hold the potential to improve safety and accessibility of this treatment in clinical practice.

Risk factors for relapse and aggravation in membranous nephropathy after COVID-19 infection

BACKGROUND

Relapse of membranous nephropathy (MN) and other glomerular diseases has been observed after COVID-19 infection. The risk factors contributing to disease progression in MN patients after contracting COVID-19 remain unclear.

METHODS

This retrospective study included 656 consecutive patients with biopsy-proven primary MN who received treatment and were regularly followed up for over six months. Logistic regression analyses were conducted to identify risk factors for disease progression.

RESULTS

Among the cohort, 555 patients (84.6%) contracted COVID-19 from November 11th, 2022, to February 22nd, 2023. Of them, 112 patients (20.2%) experienced a > 50% increase in proteinuria, including 30 patients (5.4%) who experienced nephrotic syndrome relapse. Sixteen patients (2.9%) showed immune aggravation with elevated anti-PLA2R antibody levels, and five patients (0.9%) had immune relapse characterized by antibody reoccurrence. Kidney dysfunction, defined as an eGFR reduction > 30% from baseline, occurred in 10 patients (1.8%), with two patients (0.4%) progressing to ESKD. Four patients (0.7%) died of respiratory failure. Overall, 132 patients (24.0%) experienced disease progression after COVID-19 infection. Multivariate logistic regression identified longer fever duration (OR 1.118, 95% CI 1.029-1.356, P = 0.018), withdrawal of immunosuppressants and/or steroids (OR 2.571, 95% CI 1.377-4.799, P = 0.003) and extended drug cessation (OR 1.113, 95% CI 1.045-1.186, P = 0.001) as independent risk factors for MN progression.

CONCLUSIONS

These findings suggest prompt antiviral treatment and minimizing the duration of immunosuppressant withdrawal to optimize kidney outcomes in MN patients with COVID-19.

Causality between diabetes and membranous nephropathy: Mendelian randomization

BACKGROUND

Membranous nephropathy (MN) has not yet been fully elucidated regarding its relationship with Type I and II Diabetes. This study aims to evaluate the causal effect of multiple types of diabetes and MN by summarizing the evidence from the Mendelian randomization (MR) study.

METHODS

The statistical data for MN was obtained from a GWAS study encompassing 7979 individuals. Regarding diabetes, fasting glucose, fasting insulin, and HbA1C data, we accessed the UK-Biobank, within family GWAS consortium, MAGIC, FinnGen database, MRC-IEU, and Neale Lab, which provided sample sizes ranging from 17,724 to 298,957. As a primary method in this MR analysis, we employed the Inverse Variance Weighted (IVW), Weighted Median, Weighted mode, MR-Egger, Mendelian randomization pleiotropy residual sum, and outlier (MR-PRESSO) and Leave-one-out sensitivity test. Reverse MR analysis was utilized to investigate whether MN affects Diabetes. Meta-analysis was applied to combine study-specific estimates.

RESULTS

It has been determined that type 2 diabetes, gestational diabetes, type 1 diabetes with or without complications, maternal diabetes, and insulin use pose a risk to MN. Based on the genetic prediction, fasting insulin, fasting blood glucose, and HbA1c levels were not associated with the risk of MN. No heterogeneity, horizontal pleiotropy, or reverse causal relationships were found. The meta-analysis results further validated the accuracy.

CONCLUSIONS

The MR analysis revealed the association between MN and various subtypes of diabetes. This study has provided a deeper understanding of the pathogenic mechanisms connecting MN and diabetes.

To biopsy or not to biopsy a teenager with typical idiopathic nephrotic syndrome? Start steroids first

It is well known that minimal change disease (MCD) and focal segmental glomerulosclerosis are the most common histopathology findings in children with idiopathic nephrotic syndrome. Moreover, several studies demonstrated that MCD is associated with high steroid-responsiveness and a low incidence of kidney failure, suggesting that routine kidney biopsy is not warranted. Over time, the indications for performing a kidney biopsy have become increasingly stringent, aiming to limit unnecessary invasive procedures in the paediatric population. The most recent guidelines state that a kidney biopsy is not usually necessary at disease onset. Still, it should be performed in case of atypical features suggestive of systemic diseases or glomerulonephritis and in case of steroid-resistance, to assess the different differential diagnoses, regardless of patient age. Moreover, it has been shown that the best prognostic marker in childhood nephrotic syndrome is response to treatment and that kidney histology is not accurate in predicting prognosis. Furthermore, a kidney biopsy is not necessary to predict the relapsing course. Notably, kidney biopsy is an invasive procedure and may lead to significant complications. Finally, novel non-invasive biomarkers have been validated or are in the process of being approved to guide differential diagnoses and thus limit the need for kidney biopsies in patients with typical nephrotic syndrome. In the following sections, we aim to explain why initiating steroid treatment as the initial approach in teenagers with typical nephrotic syndrome is a reasonable strategy. Additionally, we explore how kidney biopsy indications may be alleviated in this population.

[Acute kidney injury in cancer patients receiving immune checkpoint inhibitor therapy-shared guidelines of FITC/SFNDT]

Cancer treatments have been dramatically modified by the introduction and the development of immunological checkpoint inhibitors (ICI). These treatments have many side effects, including acute kidney injury (AKI). Their combination with other treatments makes the diagnosis complex. To provide guidance to physicians treating these patients, the FITC and the SFNDT have developed a set of management guidelines covering pre-treatment assessment, diagnosis of the different types of damage observed, and management of acute interstitial nephritis secondary to ICI. Collaboration between oncologists and nephrologists is mandatory. The development of onconephrology is helping to improve knowledge and identify treatment pathways. The key elements of the diagnostic process are presented. The role of renal biopsy is discussed, as it appears to be underused in relation to the expected benefits. Renal biopsy allows ICI to be continued if AKI is not related to AKI. Treatment based on glucocorticoid therapy is recommended, with regimens depending on the severity of the disease and the renal response to glucocorticoid therapy. Alternative treatments for patients resistant to corticosteroids are discussed, but strong data are lacking. Rechallenge should be discussed since it seems to be associated with a good renal prognosis.

Targeting endoplasmic reticulum stress: an innovative therapeutic strategy for podocyte-related kidney diseases

The endoplasmic reticulum (ER) is a vital organelle responsible for protein quality control, including the folding, modification, and transport of proteins. When misfolded or unfolded proteins accumulate in the ER, it triggers endoplasmic reticulum stress (ERS) and activates the unfolded protein response (UPR) to restore ER homeostasis. However, prolonged or excessive ERS can lead to apoptosis. The kidneys play a crucial role in maintaining physiological functions by excreting metabolic waste, regulating blood volume, balancing electrolytes and acid-base levels, and secreting various bioactive substances. Podocytes, epithelial cells situated outside the glomerular basement membrane, are essential for maintaining the structural integrity and permeability of the glomerular filtration barrier. Previous studies have shown that ERS in podocytes can contribute to the development of diseases such as glomerulonephritis, hereditary nephropathy, and diabetic kidney disease, potentially progressing to end-stage renal disease and causing patient mortality. As such, investigating ERS in podocytes has become a key area of focus in kidney disease research. This study examines recent advancements in understanding the effects of excessive ERS on podocytes across various kidney diseases, highlights the role of podocyte ERS in disease progression, and explores the potential therapeutic benefits of targeting the UPR to manage ERS in kidney diseases, thereby providing a scientific basis for clinical interventions.

Microparticle-assisted protein capture method facilitates proteomic and glycoproteomic analysis of urine samples

Serum tests have become a partial alternative to renal biopsy for diagnosing primary membranous nephropathy (pMN). However, urine tests, due to their non-invasive nature and ability to more accurately reflect glomerular diseases, hold great promise for the detection of pMN. However, the low protein concentration and the time-consuming sample preparation procedure of urine samples challenges the proteomic and glycoproteomic analysis to find urine-derived signatures associated with pMN. In this study, we presented a microparticle-assisted protein capture (MAPC) method to efficiently prepare urine samples. It was found that proteins and N-linked intact glycopeptides can be sensitively identified from urine samples of pMN patients and healthy controls by using this method. For comparison, proteins and N-linked intact glycopeptides from serum were also analyzed. Interestingly, discrepancy was found in the changing trends for proteins/intact glycopeptides between serum and urine. Moreover, urine derived proteins, N-linked intact glycopeptides, and glycans exhibited more pronounced changes between pMN and healthy control compared to serum sample. Notably, urine IgG4 not only up-regulated in pMN at global peptide level, its corresponding site-specific glycans were specifically identified in pMN urine with significantly up-regulations, suggested the potential of using glycosylated urine IgG4 for the non-invasive diagnosis of pMN.

Insights into Therapeutic Strategies and Longitudinal Outcomes: A Retrospective Analysis of NELL1 Positive Membranous Nephropathy Cohort

Membranous nephropathy (MN) is a rare autoimmune disease, in which the circulating autoantibodies against antigens attack podocytes. Neural Epidermal Growth Factor like 1 (NELL1) 1-associated MN is the second most common antigen, following phospholipase A2 receptor. Complementary and alternative medicine and malignancies play a pivotal role in the development of NELL1-MN. This retrospective study describes the clinical characteristics, therapeutic strategies, and longitudinal outcomes in patients with NELL1-MN at our center.

Obinutuzumab in Difficult to Treat Phospholipase A2 Receptor Positive Membranous Nephropathy: Our Experience at a Tertiary Care Center in North India

Obinutuzumab is a glycoengineered type II anti-CD20 monoclonal antibody with superior B cell cytotoxicity compared to rituximab. Various case reports suggest that in refractory phospholipase A2 receptor (PLA2R) positive membranous nephropathy (MN) patients, Obinutuzumab led to immunologic remission and improvement in proteinuria. In the present case series, we present six cases of difficult-to-treat PLA2R-associated MN refractory to prednisolone, calcineurin inhibitor (CNI), cyclophosphamide, and rituximab but subsequently responded to Obinutuzumab. Five out of six cases showed partial /complete clinical remission and immunological remission (IR) with normalization of serum albumin and stable renal function. Though this drug's long-term efficacy and impact remain unclear, it is being increasingly considered for PLA2R-associated MN resistant to standard therapy.

A bibliometric analysis from 2014 to 2024 reveals research hotspots and trends in the immunotherapy for glomerulonephritis

This study aimed to present an overview of the current status of research and important discoveries about immunotherapy for glomerulonephritis in general using bibliometric analysis. We collected the literature on immunotherapy for glomerulonephritis from the Web of Science (WOS) database for the last 10 years (2014-2024), and we assessed the mapping of knowledge using Citespace. The findings demonstrated that there were 258 articles concerning the immunotherapy for glomerulonephritis, with a faster growth after 2018. The USA, Charite Universitatsmedizin Berlin, and Anders, Hans-Joachim are the nation, organization, and writer with the highest number of publications. The most often cited reference is Rovin BH (2021) as well (5). The best partnerships are formed by prestigious universities and developed countries for glomerulonephritis research on immunotherapy. Three research hotspots in this area are rituximab, adjuvant, and antibody production erythematosus, respectively.

Crescents as Independent Risk Factor in the Progression of Primary Membranous Nephropathy

Objective

The role of crescent formation in primary membranous nephropathy (PMN) and its potential impact on prognosis remain an area of ongoing investigation. This study stratifies patients with PMN into two cohorts: one with crescents and one without. It then compares these groups to investigate the influence of crescents on the prognosis of PMN.

Methods

In this retrospective analysis, we included patients who had a confirmed diagnosis of PMN and exhibited crescents upon renal biopsy. The study population was sourced from the medical records at the Affiliated Hospital of Guangdong Medical University in Zhanjiang, China, spanning from January 2017 to June 2023. To enable a comparative analysis of clinical, pathological, and prognostic features, a control group was established, comprising 106 patients diagnosed with PMN who did not have crescent formation. These controls were randomly selected from the same time frame. Regular follow-up of the patients continued in the outpatient setting for at least six months.

Results

A total of 53 patients with PMN and crescent formation were included in this study, while 106 individuals without crescents served as a randomly selected control group. Patients with PMN and crescents exhibited higher systolic blood pressure (P = 0.015), 24-hour proteinuria (P = 0.006), serum creatinine (P = 0.029) levels, and lower glomerular filtration rate (P = 0.002), compared to those without crescents. Histological examination revealed a higher proportion of focal segmental sclerosis (P < 0.001), spherical sclerosis (P < 0.001), arteriosclerosis (P = 0.02), and interstitial fibrosis with tubular necrosis (P = 0.002) in patients with PMN and crescent formation. Immunofluorescence staining demonstrated a weaker IgG4 fluorescence intensity in patients with PMN and crescent formation. At the end of the follow-up period, patients with PMN and crescents had a lower remission rate (P = 0.022), poorer renal function (P = 0.007), and lower albumin (P = 0.039) levels. Kaplan-Meier (KM) analysis identified proteinuria and crescent formation as independent risk factors for adverse outcomes in patients with PMN (P < 0.001 and P < 0.05). Immunohistochemistry staining revealed positive expression of CD68 and CD20 in the renal interstitium of patients with PMN, regardless of the presence of crescents.

Conclusion

Crescent formation is associated with a risk of adverse outcomes in patients with PMN. Patients with crescents exhibit severe clinical and pathological features and have poorer prognoses.

A single-center retrospective study of ectopic lymphoid tissues in idiopathic membranous nephropathy: clinical pathological characteristics and prognostic value

Background

In recent years, ectopic lymphoid tissue (ELT) has been increasingly confirmed as a new biomarker for kidney injury or inflammation. However, there is insufficient research on the relationship between ELT grading and the progression of idiopathic membranous nephropathy (IMN).

Methods

A total of 147 patients with biopsy-proven IMN in our institution from March 2020 to June 2022 were classified into five grades based on the different distribution of lymphocyte subsets in renal tissue (G0: no B cells or T cells, G1: scattered B and T cells, G2: clustered B and T cells, G3: an aggregation region of B and T cells without a central network, G4: highly organized and formed zones of B and T cells with a central network of follicular dendritic cells and scattered macrophages), and were further divided into low-grade group (G0+G1), intermediate-grade group (G2) and high-grade group (G3+G4). The clinicopathological data, induction treatment response and prognosis among the three groups were analyzed and compared retrospectively.

Results

As the grading of ectopic lymphoid tissues increased, patients were older, with a higher prevalence of hypertension, a higher 24-h urinary protein level, lower baseline hemoglobin and estimated glomerular filtration rate (eGFR) levels, and more severe renal pathological damage. Logistic regression analysis showed that after 6 months of induction treatment, patients in the high-grade group were more likely to be in non-remission than those in the low-grade group (odds ratios [ORs] of the three adjusted models were 4.310, 4.239, and 5.088, respectively, P-values were 0.005, 0.006, and 0.001, respectively). Kaplan-Meier survival analysis indicated that patients in the intermediate- and high-grade groups had significantly lower renal cumulative survival rate than those in the low-grade group (P = 0.025). Univariate Cox analysis showed that the risk of adverse renal outcome was 3.662 times higher in the intermediate- and high-grade groups than in the low-grade group (95% confidence interval [CI] [1.078-12.435]; P = 0.037). Multivariate Cox analysis revealed that failure of remission at the first 6 months (hazard ratio [HR] = 5.769; 95% CI [1.854-17.950]; P = 0.002) remained an independent risk factor for poor renal outcome in patients with IMN.

Conclusions

Grading of renal ectopic lymphoid tissues correlates with disease activity and severity in IMN patients and can be used as an indicator to assess the risk of IMN progression.

Astragaloside IV relieves passive heymann nephritis and podocyte injury by suppressing the TRAF6/NF-κb axis

The pathogenesis of membranous nephropathy (MN) involves podocyte injury that is attributed to inflammatory responses induced by local immune deposits. Astragaloside IV (AS-IV) is known for its robust anti-inflammatory properties. Here, we investigated the effects of AS-IV on passive Heymann nephritis (PHN) rats and TNF-α-induced podocytes to determine the underlying molecular mechanisms of MN. Serum biochemical parameters, 24-h urine protein excretion and renal histopathology were evaluated in PHN and control rats. The expression of tumor necrosis factor receptor associated factor 6 (TRAF6), the phosphorylation of nuclear factor kappa B (p-NF-κB), the expression of associated proinflammatory cytokines (TNF-α, IL-6 and IL-1β) and the ubiquitination of TRAF6 were measured in PHN rats and TNF-α-induced podocytes. We detected a marked increase in mRNA expression of TNF-α, IL-6 and IL-1β and in the protein abundance of p-NF-κB and TRAF6 within the renal tissues of PHN rats and TNF-α-induced podocytes. Conversely, there was a reduction in the K48-linked ubiquitination of TRAF6. Additionally, AS-IV was effective in ameliorating serum creatinine, proteinuria, and renal histopathology in PHN rats. This effect was concomitant with the suppression of NF-κB pathway activation and decreased expression of TNF-α, IL-6, IL-1β and TRAF6. AS-IV decreased TRAF6 levels by promoting K48-linked ubiquitin conjugation to TRAF6, which triggered ubiquitin-mediated degradation. In summary, AS-IV averted renal impairment in PHN rats and TNF-α-induced podocytes, likely by modulating the inflammatory response through the TRAF6/NF-κB axis. Targeting TRAF6 holds therapeutic promise for managing MN.

Analysis of non-targeted serum metabolomics in patients with chronic kidney disease and hyperuricemia

Hyperuricemia (HUA) is a common complication of chronic kidney disease (CKD). Conversely, HUA can promote the disease progression of CKD. However, the molecular mechanism of HUA in CKD development remains unclear. In the present study, we applied ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to analyze the serum metabolite profiling of 47 HUA patients, 41 non-hyperuricemic CKD (NUA-CKD) patients, and 51 CKD and HUA (HUA-CKD) patients, and then subjected to multivariate statistical analysis, metabolic pathway analysis and diagnostic performance evaluation. Metabolic profiling of serums showed that 40 differential metabolites (fold-change threshold (FC) > 1.5 or<2/3, variable importance in projection (VIP) > 1, and p < 0.05) were screened in HUA-CKD and HUA patients, and 24 differential metabolites (FC > 1.2 or<0.83, VIP>1, and p < 0.05) were screened in HUA-CKD and NUA-CKD patients. According to the analysis of metabolic pathways, significant changes existed in three metabolic pathways (compared with the HUA group) and two metabolic pathways (compared with the HUA-CKD group) in HUA-CKD patients. Glycerophospholipid metabolism was a significant pathway in HUA-CKD. Our findings show that the metabolic disorder in HUA-CKD patients was more serious than that in NUA-CKD or HUA patients. A theoretical basis is provided for HUA to accelerate CKD progress.

Establishing a differential diagnosis model between primary membranous nephropathy and non-primary membranous nephropathy by machine learning algorithms

CONTEXT

Four algorithms with relatively balanced complexity and accuracy in deep learning classification algorithm were selected for differential diagnosis of primary membranous nephropathy (PMN).

OBJECTIVE

This study explored the most suitable classification algorithm for PMN identification, and to provide data reference for PMN diagnosis research.

METHODS

A total of 500 patients were referred to Luo-he Central Hospital from 2019 to 2021. All patients were diagnosed with primary glomerular disease confirmed by renal biopsy, contained 322 cases of PMN, the 178 cases of non-PMN. Using the decision tree, random forest, support vector machine, and extreme gradient boosting (Xgboost) to establish a differential diagnosis model for PMN and non-PMN. Based on the true positive rate, true negative rate, false-positive rate, false-negative rate, accuracy, feature work area under the curve (AUC) of subjects, the best performance of the model was chosen.

RESULTS

The efficiency of the Xgboost model based on the above evaluation indicators was the highest, which the diagnosis of PMN of the sensitivity and specificity, respectively 92% and 96%.

CONCLUSIONS

The differential diagnosis model for PMN was established successfully and the efficiency performance of the Xgboost model was the best. It could be used for the clinical diagnosis of PMN.

Combination Therapy With Rituximab and Low-Dose Cyclophosphamide and Prednisone in Membranous Nephropathy

Introduction

Standard treatment with cyclophosphamide (CP) or rituximab (RTX) is suboptimal. We adapted and used the low-dose regimen used in vasculitis (RTX 2 × 1000 mg, CP 1.5 mg/kg/d × 8 weeks, and prednisone [i.v. 2 × 1 g + 3 weeks oral starting at 1 mg/kg]).

Methods

High-risk, anti-PLA2R antibodies (PLA2Rab)-positive patients with membranous nephropathy (MN) were included in this single-arm prospective cohort study. PLA2Rab levels were regularly measured. We report the PLA2Rab kinetics and overall immunological and clinical remission (CR) rate.

Results

We analyzed 26 patients (15 males, aged 57 ± 14 years, PLA2Rab titer 176 [115-460] RU/ml, serum creatinine 128 [102-136] μmol/l, serum albumin 18 [14-21] g/l, and urinary protein-to-creatinine ratio [uPCR] 7.1 [5.7-10] g/10 mmol). Within 8 weeks immunological remission (IR) (enzyme-linked immunosorbent assay < 14 RU/ml) was 88 %. Proteinuria remission after initial therapy developed in 21 patients. Seven patients received renewed therapy, which resulted in proteinuria remission in all. IR and CR were associated with baseline PLA2Rab tertile. Five of 7 patients in need of additional therapy were identified at 4 weeks after start of therapy by PLA2Rab half-life (T1/2) > 7 days. Serious adverse events occurred in 4 patients. Adverse events were mild; leukopenia was most frequent.

Conclusion

Low-dose triple therapy induced a rapid IR and CR in most patients. Patients with insufficient clinical response were characterized by high baseline PLA2Rab levels and longer PLA2Rab T1/2. Assessment of PLA2Rab levels within 2 to 4 weeks after start of therapy may enable to identify patients who need more intensive therapy.

Evidence from mendelian randomization identifies several causal relationships between primary membranous nephropathy and gut microbiota

BACKGROUND

Research has showcased a correlation between disruptions in gut microbiota and primary membranous nephropathy (pMN), giving rise to the concept of the 'gut-kidney axis'. However, the precise relationship between gut microbiota and pMN remains elusive. Hence, this study endeavors to investigate whether a causal relationship exists between gut microbiota and pMN utilizing Mendelian randomization (MR) analysis.

METHODS

The primary method employed for MR analysis is the inverse variance weighting method, supplemented by MR-Egger and the weighted median method, to infer causality. This approach was validated within the pMN cohort across two distinct populations.

RESULTS

At the species level, the abundance of Bifidobacterium bifidum and Alistipes indistinctus was negatively correlated with the risk of pMN. Conversely, pMN was positively associated with Bacilli abundance at the class level, Lachnospiraceae abundance at the family level, and Dialister abundance at the genus level. Specifically, at the species level, pMN was positively correlated with the abundance of Ruminococcus lactaris, Dialister invisus, and Coprococcus_sp_ART55_1.

CONCLUSION

These findings lay the groundwork for future research exploring the interplay between pMN and the gut microbiota, with substantial implications for the prevention and treatment of pMN and its associated complications.

Anti Phospholipase A2 Receptor 1 Antibodies and Membranous Nephropathy Recurrence After Kidney Transplantation

Introduction

Membranous nephropathy can lead to end-stage kidney disease, for which kidney transplantation is the preferred therapy. However, the disease often relapses, which can impact allograft survival.

Methods

We conducted a prospective multicenter study in France involving 72 patients with membranous nephropathy who were awaiting and then underwent kidney transplantation. In addition, we established a retrospective validation cohort of 65 patients. The primary objective was to evaluate the prognostic significance of pretransplant anti phospholipase A2 receptor 1 (PLA2R1) antibodies on the recurrence of membranous nephropathy. The study also assessed the incidence rate, time to onset, and risk factors for recurrence, as well as allograft outcome.

Results

The prospective cohort showed a 26% cumulative incidence of membranous nephropathy recurrence after a median follow-up of 23.5 months. This was confirmed by a 28% cumulative incidence after a median follow-up of 67 months in the retrospective cohort. A strong association was found between the presence of anti-PLA2R1 antibodies prior to transplantation and the risk of disease recurrence (risk ratio = 5.9; 95% confidence interval [CI]: 2.3-15.7; P < 0.0001). These results were confirmed in the retrospective cohort. Monitoring of anti-PLA2R1 antibodies in the immediate posttransplant period is of limited value, because recurrence occurred early in the first 6 months (median delay of 5 [3-14] months) after transplantation despite decreasing antibody levels.

Conclusion

The presence of anti-PLA2R1 antibodies prior to transplantation was a strong predictor of recurrence of allograft membranous nephropathy. An individualized immunomonitoring and management strategy for kidney transplant candidates with anti-PLA2R1-associated membranous nephropathy should be considered.

Fibrinogen-albumin ratio predicts treatment response in phospholipase A2 receptor-associated membranous nephropathy with nephrotic syndrome

BACKGROUND

The M-type phospholipase A2 receptor (PLA2R)-associated primary membranous nephropathy (PMN) is an immune-related disease in adults with increasing morbidity and variable treatment response, in which inflammation may contribute to the multifactorial immunopathogenesis. The relationship between fibrinogen-albumin ratio (FAR), serving as a novel inflammatory biomarker, and PMN is still unclear. Therefore, this study aims to clarify the association between FAR and disease activity and therapy response of PMN.

METHODS

110 biopsy-proven phospholipase A2 receptor (PLA2R) -associated PMN participants with nephrotic syndrome from January 2017 to December 2021 were recruited in the First Affiliated Hospital of Nanjing Medical University. The independent risk factors of non-remission (NR) and the predictive ability of FAR were explored by Cox regression and receiver-operating characteristic (ROC) curve analysis. According to the optimal cutoff value, study patients were categorized into the low-FAR group (≤the cutoff value) and the high-FAR group (>the cutoff value). Spearman's correlations were used to examine the associations between FAR and baseline clinicopathological characteristics. Kaplan-Meier method was used to assess the effects of FAR on remission.

RESULTS

In the entire study cohort, 78 (70.9%) patients reached complete or partial remission (CR or PR). The optimal cutoff value of FAR for predicting the remission outcome (CR + PR) was 0.233. The Kaplan-Meier survival analysis demonstrated that the high-FAR group (>0.233) had a significantly lower probability to achieve CR or PR compared to the low-FAR group (≤0.233) (Log Rank test, p = 0.021). Higher levels of FAR were identified as an independent risk factor for NR, and the high-FAR group was associated with a 2.27 times higher likelihood of NR than the low-FAR group (HR 2.27, 95% CI 1.01, 5.13, p = 0.048). These relationships remained robust with further analysis among calcineurin inhibitors (CNIs)-receivers. In the multivariate Cox regression model, the incidence of NR was 4.00 times higher in the high-FAR group than in the low-FAR group (HR 4.00, 95% CI 1.41, 11.31, p = 0.009). Moreover, ROC analysis revealed the predictive value of FAR for CR or PR with a 0.738 area under curve (AUC), and the AUC of anti-PLA2R Ab was 0.675. When combining FAR and anti-PLA2R Ab, the AUC was boosted to 0.766.

CONCLUSIONS

FAR was significantly correlated with proteinuria and anti-PLA2R Ab in PMN. As an independent risk factor for NR, FAR might serve as a potential inflammation-based prognostic tool for identifying cases with poor treatment response, and the best predictive cutoff value for outcomes was 0.233.

Prognostic value of serum complement cleavage factor Bb in idiopathic membranous nephropathy and establishment of nomogram model

Complement activation is involved in idiopathic membranous nephropathy (IMN). We aimed to investigate the relationship of serum complement cleavage factor Bb with IMN progression, and to establish a model for early prediction of kidney outcomes. We measured serum factor Bb in a retrospective cohort of 449 IMN patients at the time of kidney biopsy. Cox regression analysis showed that higher levels of serum factor Bb were independently associated with IMN progression event defined as end-stage renal disease or ≥ 40% decline in estimated glomerular filtration rate. Patients in the middle and highest tertiles of serum factor Bb had respectively 2.1-, and 2.6-fold higher risk for disease progression compared with those in the lowest tertile. We developed an optimized prognostic nomogram model incorporating age, log serum anti-PLA2R antibody, log serum Bb, proteinuria and tubular atrophy/interstitial fibrosis. The model demonstrated good predictive ability with a concordance index of 0.77 (bootstrap-corrected of 0.76) for predicting 3-, and 5-year kidney survival. Calibration curves and decision curve analysis confirmed the model's good calibration and clinical utility. Our findings suggest that serum factor Bb may serve as an essential prognostic indicator of IMN. The novel nomogram model may offer important guidance on the management of this patient population.

Melatonin Alleviates Albumin-Induced Tubular Cell Injury by Activating Clock-Controlled Nuclear Enriched Abundant Transcript 1-Mediated Proliferation

The pleiotropic and protective effects of melatonin have been demonstrated in a variety of animal models of renal injury. While coding RNAs regulated by melatonin in renal tissues are well identified, the functional involvement of long noncoding RNAs (lncRNAs) in melatonin signaling remains undefined. This study identified nuclear enriched abundant transcript 1 (NEAT1), a clock-controlled lncRNA that was upregulated by melatonin through the BMAL1/CLOCK heterodimer in renal tubular epithelial cells (TECs). Mechanistic studies showed that melatonin enhanced NEAT1 expression via increasing BMAL1 stability and thereby the enrichment of BMAL1 on NEAT1's promoter. Further studies have revealed that NEAT1 promotes the proliferation of TECs by increasing levels of H3K27ac and H3K4me1 at the promoter regions of the proliferation gene MKI67. Treatment of albumin-injured TECs with melatonin promoted proliferation by transactivating NEAT1 and restoring the expression levels of core clock genes and MKI67. Moreover, melatonin treatment ameliorated proteinuria, hypoalbuminemia, and fibrotic lesions, which was correlated with increased levels of core clock genes, H3K27ac, Mki67, and Neat1 in experimental MN kidneys. Melatonin mediates a novel regulatory axis, BMAL1-NEAT1-MKI67, in TEC proliferation, establishing potential therapeutic targets for MN and other renal diseases.

Obinutuzumab in untreated primary membranous nephropathy: An observational case series

BACKGROUND

As an initial treatment for primary membranous nephropathy (PMN), there remains a significant proportion of patients for whom rituximab is not fully effective. Here, we aimed to assess the effectiveness and safety of obinutuzumab as initial treatment in patients with PMN.

METHODS

In this observational case series, patients diagnosed with PMN and treated with obinutuzumab as initial treatment were included. Treatment response was assessed by 24-h urine total protein (24 h UTP) and serum albumin, and immunologic remission was assessed by phospholipase A2 receptor (PLA2R) antibodies.

RESULTS

Twelve patients with PMN receiving obinutuzumab as initial treatment were included. Over 6 months, a statistically significant reduction in 24 h UTP levels (p = 0.003) and an increase in serum albumin levels were observed (p < 0.001). By the 6-month follow-up, two patients (16.7%) achieved complete remission, eight (66.6%) reached partial remission, and two (16.7%) showed no remission. Immunological remission was observed in 44.4% of evaluable patients (n = 9) after 3 months, increasing to 100% (6/6) at 6 months. Except for cases 1, 2, and 3, the total B cell counts in the remaining patients fell to less than 5 cells/μL before the administration of the second dose of obinutuzumab, including seven patients with counts as low as 0 cells/μL. Mild to moderate treatment-related adverse events (TRAEs) were reported in 58.3% (7/12) of the patients. No serious TRAEs were reported.

CONCLUSIONS

Obinutuzumab demonstrates promising potential as an initial treatment for PMN, with good effectiveness and a manageable safety profile. Further large-scale prospective studies are needed to confirm these findings.

Single-dose telitacicept therapy for refractory idiopathic membranous nephropathy: A case series

Key Clinical Message

We report three cases of IMN from our center, where patients received a single dose of telitacicept after showing no response to conventional treatments. Although one case did not respond, the other two cases achieved complete or partial remission of proteinuria. These cases illustrates the telitacicept may offer new hope for the treatment of IMN.

Abstract

Despite the variety of treatment options available, effective therapies for refractory membranous nephropathy remain lacking. Recently, some reports have suggested that telitacicept is a new therapeutic option. However, only a few published studies have documented the use of telitacicept for treating idiopathic membranous nephropathy (IMN). We present three cases of IMN from our center, where patients received a single dose of telitacicept after showing no response to conventional treatments, including glucocorticoids, tacrolimus, mycophenolate mofetil, cyclophosphamide, cyclosporine, and rituximab. Although one case did not respond, the other two cases achieved complete or partial remission of proteinuria. Thus, telitacicept may offer new hope for the treatment of refractory membranous nephropathy.

Obinutuzumab treatment for membranous nephropathy: effectiveness and safety concerns during the COVID-19 pandemic

Background

Obinutuzumab is a humanized and glycoengineered anti-CD20 monoclonal antibody that has been shown to induce more profound B-cell depletion than rituximab. The effectiveness and safety of obinutuzumab in the treatment of membranous nephropathy remain unclear.

Methods

This was a retrospective study conducted in Huashan Hospital, Fudan University between 1 December 2021 and 30 November 2023. Patients with membranous nephropathy were included to assess the effectiveness and safety of obinutuzumab and prevalence of severe pneumonia during the outbreak of COVID-19 in China.

Results

Eighteen patients were included in the study assessing the effectiveness of obinutuzumab. After a 12-month follow-up, 14 patients (78%) achieved remission, with six (33%) achieving complete remission and eight (44%) achieving partial remission. Among the 18 obinutuzumab-treated patients contracting COVID-19 for the first time, six (33%) developed severe pneumonia, and one died. By contrast, two of the 37 patients receiving glucocorticoids combined with cyclophosphamide, and none of the 44 patients on calcineurin inhibitors or the 46 patients on rituximab developed severe pneumonia. However, compared to patients receiving rituximab or glucocorticoids plus cyclophosphamide, the obinutuzumab-treated patients had a longer duration of membranous nephropathy and immunosuppressive therapy. Therefore, cardinal matching was employed to balance these baseline characteristics. Owing to small sample size for each regimen, patients receiving all the three non-obinutuzumab immunosuppressive regimens were grouped as a control cohort. After matching for age, gender, remission status, duration of membranous nephropathy, duration of immunosuppressive therapy, and ongoing immunosuppression, the obinutuzumab-treated patients still had a significantly higher incidence of severe pneumonia compared to those on other regimens (P = .019).

Conclusion

Obinutuzumab was an effective treatment option for patients with membranous nephropathy. On the other hand, it was associated with a higher incidence of severe pneumonia following COVID-19 infection compared to other immunosuppressive regimens.

Different Dosage Regimens of Rituximab in Primary Membranous Nephropathy Treatment: A Systematic Review

Primary membranous nephropathy (PMN) is one of the prevalent pathological types of adult primary nephrotic syndrome. Pathogenic autoantibodies targeting podocyte antigens such as phospholipase A2 receptor (PLA2R) lead to the disease. Patients frequently experience notable adverse effects when treated with conventional immunosuppressive therapies. Rituximab (RTX), a mouse/human monoclonal antibody, selectively depletes B cells and leads to a decrease in the antibody levels in the circulation, which helps to alleviate membranous nephropathy. Various RTX dosage regimens have been applied globally in the PMN treatment with satisfactory effects. Nevertheless, the optimal dosage of RTX has yet to be determined. This article reviews the application of different doses of RTX in the management of PMN so far.

Epitope Spreading in Immune-Mediated Glomerulonephritis: The Expanding Target

Epitope spreading is a critical mechanism driving the progression of autoimmune glomerulonephritis. This phenomenon, where immune responses broaden from a single epitope to encompass additional targets, contributes to the complexity and severity of diseases such as membranous nephropathy (MN), lupus nephritis (LN), and ANCA-associated vasculitis (AAV). In MN, intramolecular spreading within the phospholipase A2 receptor correlates with a worse prognosis, while LN exemplifies both intra- and intermolecular spreading, exacerbating renal involvement. Similarly, ANCA reactivity in AAV highlights the destructive potential of epitope diversification. Understanding these immunological cascades reveals therapeutic opportunities-targeting early epitope spreading could curb disease progression. Despite promising insights, the clinical utility of epitope spreading as a prognostic tool remains debated. This review provides a complete overview of the current evidence, exploring the dual-edged nature of epitope spreading, the intricate immune mechanisms behind it, and its therapeutic implications. By elucidating these dynamics, we aim to pave the way for more precise, targeted interventions in autoimmune glomerular diseases.

Exploring PLA2R and HLA in membranous nephropathy: A narrative review of pathogenic mechanisms and emerging therapeutic potentials

Membranous Nephropathy (MN), a non-inflammatory autoimmune glomerulopathy, is a prominent cause of nephrotic syndrome, predominantly affecting Caucasian adults. It is characterized by significant thickening of the glomerular basement membrane, a direct result of immune complex deposition. Fundamental to its pathogenesis are the Phospholipase A2 receptor (PLA2R) and Human Leukocyte Antigens (HLA), which play crucial and interconnected roles. Specifically, PLA2R serves as the primary antigen, while HLA molecules facilitate MN-specific immune responses, thereby providing key insights into the disease's etiology. This study critically examines the roles of PLA2R and HLA in MN, with a particular focus on the antigenic epitopes of PLA2R. Given MN's complex nature, personalized therapeutic interventions are essential. Accordingly, targeting immunogenic epitopes has emerged as a transformative approach, aimed at modulating specific immune responses without disrupting overall immune function. Numerous studies and clinical trials have been advancing the application of these epitopes in therapeutic strategies. Nevertheless, challenges such as identifying effective epitopes, enhancing epitope-specific responses, and optimizing therapeutic dosing remain. This narrative review addresses these challenges in depth, offering a comprehensive insight into the pathology and emerging treatment strategies for MN.

A Clinicopathological Analysis of Membranous Nephropathy and Its Correlation With the Immunohistochemical Expression of Phospholipase A2 Receptor (PLA2R) in Renal Biopsies in a Tertiary Care Center

Background  Membranous nephropathy (MN) is the second most common adult-onset nephrotic syndrome worldwide. Traditionally, these were classified as primary and secondary, with primary causes showing higher positivity for various antigens, including M-type phospholipase A2 receptor (PLA2R), a key antigen located in the podocyte against which antibodies are directed. Aim The aim of this study is to analyze the cases diagnosed as MN with clinicopathological parameters and PLA2R positivity by immunohistochemistry in renal biopsies. Methods A retrospective observational study of 65 cases of MN diagnosed in renal biopsies by light microscopy and confirmed by ancillary studies from the Department of Pathology, Sri Ramachandra Medical College and Research Institute over a period of three years (2021-2023). The demographic profile and patient details were obtained from the hospital information system and archival case files. The description of categorical variables was expressed as frequency and percentage. The Chi-squared test and Fisher's exact test were employed to compare the distribution of qualitative variables between the groups. Results This case study includes 65 membranous nephropathy cases, of which 47.7% were diagnosed as primary MN and 52.3% as secondary MN. Of these, serum antinuclear antibody (ANA) positivity was seen in 80.6% of cases of primary MN and 58.8% of cases of secondary MN. Elevated serum C3/C4 levels were noted in 51.6% of primary MN and 47.1% of secondary MN (Ref. C3 = 90-180mg/dl; C4 = 10-40mg/dl). Immunofluorescence for IgG showed a nonspecific association between primary and secondary MN. Immunohistochemistry (IHC) for PLA2R showed positivity in 72.3% of primary MN cases and 27.7% of secondary MN cases. The Chi-squared test and Fisher's exact test showed statistical significance for these parameters. Conclusion This study signifies that primary MN is more frequently associated with positive immunohistochemical expression of PLA2R. These findings help in characterizing these cases as antigen-specific and have helped in the ongoing validation of PLA2R IHC as a diagnostic marker, which aids in monitoring the disease progression, remission, and recurrence. Despite the availability of various modalities for estimating the levels of anti-PLA2R, diagnostic challenges persist. Hence, most renal laboratories continue to adopt renal biopsy staining for IHC PLA2R to identify and monitor the disease progression.

Lupus-like membranous nephropathy during the postpartum period expressing glomerular antigens exostosin 1/exostosin 2 and phospholipase A2 receptor: a case report

Recently, several target antigens of membranous nephropathy (MN), such as phospholipase A2 receptor (PLA2R) and exostosin 1/exostosin 2 (EXT1/2), have been discovered. A 30-year-old woman was referred to our hospital with nephrotic range proteinuria and microscopic hematuria. She was first noted to have proteinuria before pregnancy, and her proteinuria worsened in the postpartum period. A renal biopsy showed MN. Immunofluorescence microscopy showed IgG, IgA, IgM, C3, C4, and C1q depositions in the mesangial area and glomerular capillary walls (GCWs). Regarding the IgG subclass, IgG1 and IgG3 were detected on glomeruli. Electron microscopy showed subepithelial electron-dense deposits (EDDs). EDDs were also detected in paramesangial and subendothelial areas. The diagnosis of membranous lupus nephritis (MLN) was suspected, but she did not fulfill the criteria for systemic lupus erythematosus. Neither anti-nuclear antibody nor hypocomplementemia were detected. We further evaluated glomerular EXT1/2 expressions, which were evident on GCWs. In addition, PLA2R was also detected on GCWs, although serum antibody for PLA2R was negative. She responded to immunosuppressive therapy with decreased proteinuria. In the present case, glomerular PLA2R expression implied the possibility of primary MN. However, pathological findings with a full-house staining pattern and glomerular EXT1/2 expressions were very similar to those of lupus-associated MN. Glomerular PLA2R expression appeared not to reflect immunocomplexes of PLA2R and autoantibody when considering the results for glomerular IgG subclass and the absence of serum anti-PLA2R antibody. Collectively, it is plausible that this was a case of a relatively young postpartum female who developed latent MLN rather than primary MN.

Clinical characteristics of membranous nephropathy after allogeneic hematopoietic stem cell transplantation: A real-world multicenter study

Membranous nephropathy (MN) is a rare complication that can occur after allogeneic hematopoietic stem cell transplantation (allo-HSCT). MN patients may develop nephrotic syndrome or even kidney failure, which greatly affects their quality of life and prognosis. However, current knowledge regarding MN after allo-HSCT is limited. Thus, a multicenter nested case‒control study was conducted. Patients who had been diagnosed with MN after allo-HSCT were retrospectively identified at 8 HSCT centers. A total of 51 patients with MN after allo-HSCT were included. The median age of MN patients after allo-HSCT was 38 years, and the median duration from HSCT to MN was 18 months. The use of HLA-matched donors (P = 0.0102) and peripheral blood as the graft source (P = 0.0060) were identified as independent predisposing risk factors for the onset of MN after allo-HSCT. Compared to those in the control group, the incidence of extensive chronic graft-versus-host disease was greater in the MN patients (P = 0.0002). A total of 31 patients developed nephrotic syndrome. Patients receiving combination treatments of corticosteroids and immunosuppressants appeared to have better outcomes. In conclusion, MN is a rare but occasionally severe complication following HSCT and may require active treatment.

Bibliometric and visual analysis of membranous nephropathy literature from 2010 to 2023

Background

Membranous glomerulonephritis, also known as membranous nephropathy (MN), is a common cause of nephrotic syndrome in adults. Despite extensive research on MN, bibliometric studies on the subject are scarce. Therefore, this study aimed to provide a visual analysis of global trends in membranous nephropathy research over the past 13 years.

Methods

This study conducted a bibliometric and visual analysis of global trends in MN research from 2010 to 2023. Articles related to MN were retrieved from the Web of Science Core Collection (WoSCC) database. Tools such as CiteSpace and VOSviewer were utilized to analyze publications, countries, institutions, authors, publishing journals, co-cited references, and keywords to identify the current state and future trends in MN research.

Results

The analysis encompassed 1,624 publications, showing an annual increase from 2010 to 2023. The People's Republic of China emerged as the most active country in this field, while France's Sorbonne Universite and Institut National de la Sante et de la Recherche Medicale (Inserm) led in publication volume among academic institutions. Debiec Hanna stood out as the most prolific author. BMC Nephrology had the highest number of publications, making it the most favored journal in the field. The article with the greatest co-citation intensity was "Primary Membranous Nephropathy," a review published in 2017.

Conclusion

This study shows that there has been increasing interest in membranous nephropathy over the past 13 years. The most frequently encountered keywords were "membranous nephropathy" "nephrotic syndrome," and "glomerulonephritis." Analysis of emerging terms indicated that "a2 receptor antibody," "domain containing 7a," and "t cell" may remain prominent subjects of research in the forthcoming years. The findings highlight key research trends and areas of interest that can inform researchers, clinicians, and policymakers about the current state of MN research and help guide future research directions and clinical practice.