Treatment of membranous nephropathy: time for a paradigm shift

How to Choose Treatment Regimens for Idiopathic Membranous Nephropathy Patients with PLA2R-Negative: A Single-Center Retrospective Cohort Study

Background

Cyclophosphamide, tacrolimus, and rituximab (RTX) are first-line treatments for idiopathic membranous nephropathy (IMN), regardless of PLA2R status. While the efficacy of RTX in IMN patients with PLA2R-positive has been well-documented, its effectiveness in IMN patients with PLA2R-negative remains understudied. This study aimed to evaluate the efficacy and adverse events of these three treatment regimens in IMN patients with PLA2R-negative.

Methods

This study included 46 PLA2R-negative IMN patients confirmed by renal biopsy and immunofluorescence from the Department of Nephrology, the Second Affiliated Hospital of Nanchang University between September 2021 and October 2023. We compared clinical remission rates, and side effects at 3, 6, and 12 months follow-up in 14 patients who received prednisolone combined with cyclophosphamide (cyclophosphamide group), in 11 patients who treated with prednisolone combined with tacrolimus (tacrolimus group), and 21 patients who treated with rituximab (RTX group).

Results

Baseline characteristics were similar among the three groups. At the 12-month follow-up, the complete response rate was significantly higher in the cyclophosphamide and tacrolimus groups compared to the RTX group (p = 0.029). However, there were no significant differences in cumulative complete remission rates or cumulative composite remission rates among the three groups during the follow-up period (p = 0.192, p = 0.212). Severe adverse events occurred in all groups, but the differences were not statistically significant (p > 0.05).

Conclusion

Cyclophosphamide and tacrolimus appear to offer long-term benefits for PLA2R-negative IMN patients, with tacrolimus demonstrating superior efficacy among the treatment options evaluated. These insights offer important guidance for clinical decision-making in the management of PLA2R-negative IMN. However, further large-scale, multicenter studies with long-term follow-up are necessary to confirm these findings.

Prognostic Factors of Proteinuria Remission in Primary Membranous Nephropathy

Primary membranous nephropathy is a leading cause of nephrotic syndrome in adults, characterized by immune complex deposition in the glomerular basement membrane. Predicting proteinuria remission is essential for guiding treatment decisions, optimizing immunosuppressive therapy, and improving renal outcomes. Traditional prognostic markers, such as anti-PLA2R antibody status and baseline proteinuria levels, offer valuable insights into disease progression. However, recent research has identified additional biomarkers that may enhance risk stratification and refine individualized treatment strategies. Serum-based markers, such as uric acid and inflammatory indices, may indicate systemic changes that impact disease progression. Urinary biomarkers, including microhematuria, α1-microglobulin, and CXCL13, have been proposed as potential predictors of disease activity and remission likelihood. Furthermore, histopathological features, such as glomerular basement membrane thickness, tubulointerstitial injury, and acute kidney injury, provide structural correlates that may inform prognosis. This review explores both established and emerging prognostic indicators across various biological domains. Understanding these predictors can aid in developing personalized therapeutic strategies, optimizing disease management, and improving patient outcomes in primary membranous nephropathy.

A multicenter retrospective study on comparing the efficacy and safety of the therapy of intermittent cyclophosphamide and corticosteroids versus rituximab for primary membranous nephropathy

BACKGROUND

Few clinical studies compare the long-term remission, relapse, and safety of rituximab (RTX) or a combination of intermittent intravenous infusion of cyclophosphamide (CTX) and oral corticosteroid for primary membranous nephropathy (PMN) patients.

METHODS

We collected multicenter retrospective data on PMN patients with nephrotic syndrome who received RTX or intermittent intravenous CTX with oral corticosteroids between 1 January 2019 and 31 January 2024. Patients were followed up until two years after receiving immunotherapy. The primary outcomes were a composite of complete or partial remission rates at 6, 12, and 24 months. The secondary outcomes were the relapse and safety evaluation.

RESULTS

Forty patients treated with RTX and 27 with the CTX regime were available for analysis. No significant difference in the remission rate at 6, 12, or 24 months was observed between the two groups (p > .05). Kaplan-Meier's survival analysis showed that the relapse-free cumulative survival rate of the RTX group was superior to that of the CTX group (p = .023). Compared with baseline, both the media of urine protein and serum albumin levels in the two groups showed a significant improvement at 6 months and maintained through to the second year. No significant difference in the occurrence of total side effects between the two groups (p = .160).

CONCLUSIONS

There was no difference in remission rates and safety between RTX versus intermittent intravenous CTX combined with oral corticosteroid treatment for patients with PMN within 2 years. RTX appeared to have benefits in terms of prolonging relapse-free survival.

Overview of Immunological Response in Urological Membranous Nephropathy: Focus on Cytokine and Treatment Options

Membranous nephropathy (MN) is an autoimmune disease that is caused by the production of autoantibody against glomerular podocyte antigens by immune cells due to the lack of self-tolerance mechanisms. Similar to many autoimmune diseases, the pathogenesis of MN is still vague and many experiments are being conducted to detect the antigens and genetic reasons for MN illness. Recently, new antigens, such as exotosin 1/exotosin 2, neural EGF-like-1, semaphorin 3B, and protocadherin 7 have been identified in MN patients who did not have presence of antiphospholipase A2 receptor antigen. What is more, cytokines, which are molecules that regulate immune responses, have been found to have harmful effects in various autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and MN. The role of cytokines and treatment strategies in MN patients is discussed in this article. As the understanding of the disease improves, targeted therapies that focus on specific antigens or cytokines may be developed to effectively manage MN.

The association between serum complement 4 and relapse of primary membranous nephropathy: a multicenter retrospective cohort study

Background

Relapse after initial remission reduces renal survival in patients with primary membranous nephropathy (PMN). In this study, we aim to identify risk factors of relapse in PMN and construct a model to identify patients at high risk of relapse early.

Methods

We conducted a multi-center retrospective study using the China Renal Data System database, which includes data from 24 urban academic centers across China. A prediction model based on the Cox proportional hazards model was derived in the derivation group and validated in the validation group.

Result

515 patients with biopsy-proven PMN achieving initial remission were enrolled. 32.62% of patients subsequently relapsed during a median of 6.08 months. Lower serum albumin (Alb) (per 1 g/L decrease, hazard ratio [HR] =1.48, 95% confidence interval [CI] 1.29-1.78, p < 0.001), lower estimated glomerular filtration rate (eGFR) (per 10 mL/min/1.73m2 decrease, HR =1.14, 95% CI 0.97-1.49, p < 0.001), higher serum complement 4 (C4) (per 0.1 g/L increase, HR =1.89, 95% CI 1.32-3.22, p = 0.012), partial remission (PR) (HR =2.28, 95%CI 1.74-4.04, p < 0.001), and treatment with calcineurin inhibitors (CINs) (HR =1.33, 95%CI 1.04-1.64, p < 0.001) at the time of remission were risk factors for relapse. C-statistic, time-dependent areas under the receiver operating characteristic curve, and calibration plots confirmed that the model had excellent discrimination and calibration in predicting PMN relapse. The anti-phospholipase A2 receptor antibody (aPLA2Rab) titers and pathologic features did not substantially improve the model.

Conclusion

Our study confirms the well-known low Alb and eGFR, PR, and treatment of CNIs at the time of remission as risk factors for PMN relapse, but aPLA2Rab and pathologic features may not predict relapse. In addition, it is the first study to show serum C4 is associated with PMN relapse. We suggest that complement-targeted therapies may be a potential therapy to prevent PMN relapse.

Investigating potential drug targets for IgA nephropathy and membranous nephropathy through multi-queue plasma protein analysis: a Mendelian randomization study based on SMR and co-localization analysis

BACKGROUND

Membranous nephropathy (MN) and IgA nephropathy (IgAN) pose challenges in clinical treatment with existing therapies primarily focusing on symptom relief and often yielding unsatisfactory outcomes. The search for novel drug targets remains crucial to address the shortcomings in managing both kidney diseases.

METHODS

Utilizing GWAS data for MN (ncase = 2150, ncontrol = 5829) and IgAN (ncase = 15587, ncontrol = 462197), instrumental variables for plasma proteins were derived from recent GWAS. Sensitivity analysis involved bidirectional Mendelian randomization analysis, MR Steiger, Bayesian co-localization, and Phenotype scanning. The SMR analysis using eQTL data from the eQTLGen Consortium was conducted to assess the availability of selected protein targets. The PPI network was constructed to reveal potential associations with existing drug treatment targets.

RESULTS

The study, subjected to the stringent Bonferroni correction, revealed significant associations: four proteins with MN and three proteins with IgAN. In plasma protein cis-pQTL data from two cohorts, an increase in one standard deviation in PLA2R1 (OR = 2.01, 95%CI = 1.83-2.21), AIF1 (OR = 9.04, 95%CI = 4.69-17.41), MLN (OR = 3.79, 95%CI = 2.12-6.78), and NFKB1 (OR = 29.43, 95%CI = 7.73-112.0) was associated with an increased risk of MN. Additionally, in plasma protein cis-pQTL data, a standard deviation increase in FCGR3B (OR = 1.15, 95%CI = 1.09-1.22) and BTN3A1 (OR = 4.05, 95%CI = 2.65-6.19) correlated with elevated IgAN risk, while AIF1 (OR = 0.58, 95%CI = 0.46-0.73) exhibited IgAN protection. Bayesian co-localization indicated that PLA2R1 (coloc.abf-PPH4 = 0.695), NFKB1 (coloc.abf-PPH4 = 0.949), FCGR3B (coloc.abf-PPH4 = 0.909), and BTN3A1 (coloc.abf-PPH4 = 0.685) share the same variants associated with MN and IgAN. The SMR analysis indicated a causal link between NFKB1 and BTN3A1 plasma protein eQTL in both conditions, and BTN3A1 was validated externally.

CONCLUSION

Genetically influenced plasma levels of PLA2R1 and NFKB1 impact MN risk, while FCGR3B and BTN3A1 levels are causally linked to IgAN risk, suggesting potential drug targets for further clinical exploration, notably BTN3A1 for IgAN.

Novel approaches to primary membranous nephropathy: Beyond the KDIGO guidelines

Primary membranous nephropathy (PMN) is an immune-mediated glomerular disease. Rituximab (RTX) is recommended as a first-line immunosuppressive therapy and shows high clinical efficacy, but the optimal doses remain controversial. Approximately 20%-40% of PMN patients experience RTX resistance and failure. Reduced bioavailability, RTX internalization and attack, anti-RTX antibody production, autoreactive B-cell reservoirs and chronic and irreversible renal damage may contribute to this problem. Therefore, new treatment modalities are needed to compensate for this deficit. New interventions and new dose combinations are being proposed. Multiple drug combination therapies show comparable clinical efficacy to conventional treatments by blocking the production of disease-causing antibodies in multiple directions, and can reduce single-agent doses without increasing adverse effects. New therapies that directly target B cells, plasma cells, and antibody production have shown encouraging results. In addition, new techniques for sweeping antibodies and chimeric antigen receptor T-cell therapy also may be promising strategies for PMN. Immunoadsorption could be used as an auxiliary choice for severe cases. This article explores new treatments for PMN and highlights possible mechanisms for potential new technologies that offer new ideas for treatment.

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.

Effect of immunosuppressive agents on clinical outcomes in idiopathic membranous nephropathy

BACKGROUND

Few comparative studies on the effects of immunosuppressants in patients with idiopathic membranous nephropathy have been conducted.

METHODS

Data from 489 patients who received conservative treatment or immunosuppressants were retrospectively analyzed by propensity score matching. Primary outcomes were complete or partial remission (CR or PR) of proteinuria, and secondary outcomes were renal survival and infection.

RESULTS

Of the 489 patients, 357 (73.0%) received immunosuppressants. Propensity score matching identified 82 patients from the conservative group and 82 patients in the immunosuppressant group. CR or PR at 12 months was significantly higher in the immunosuppressant group compared with the conservative group for the total population (p = 0.002) and the propensity score-matched population (p = 0.02). The use of immunosuppressants was significantly more effective with respect to achieving a CR or PR at 12 months in patients who were aged <65 years or female, or who had a proteinuria level of ≥4.0 g/g or an estimated glomerular filtration rate of ≥60 mL/min/1.73 m2 (p < 0.05). Renal survival was similar between patients receiving immunosuppressants and conservative treatment in both the total and matched populations. The immunosuppressant group (21.8%) had a significantly higher incidence of infections compared with the conservative group (13.6%) for the total population (p = 0.03), but statistical significance disappeared in the matched population (p > 0.99).

CONCLUSION

The remission rate was significantly higher in the immunosuppressant group than in the conservative group, particularly in the subgroup of patients who were young or female, or those with heavy proteinuria loads or good renal function.

Current progress in CAR-based therapy for kidney disease

Despite significant breakthroughs in the understanding of immunological and pathophysiological features for immune-mediated kidney diseases, a proportion of patients exhibit poor responses to current therapies or have been categorized as refractory renal disease. Engineered T cells have emerged as a focal point of interest as a potential treatment strategy for kidney diseases. By genetically modifying T cells and arming them with chimeric antigen receptors (CARs), effectively targeting autoreactive immune cells, such as B cells or antibody-secreting plasma cells, has become feasible. The emergence of CAR T-cell therapy has shown promising potential in directing effector and regulatory T cells (Tregs) to the site of autoimmunity, paving the way for effective migration, proliferation, and execution of suppressive functions. Genetically modified T-cells equipped with artificial receptors have become a novel approach for alleviating autoimmune manifestations and reducing autoinflammatory events in the context of kidney diseases. Here, we review the latest developments in basic, translational, and clinical studies of CAR-based therapies for immune-mediated kidney diseases, highlighting their potential as promising avenues for therapeutic intervention.

The fate of immune complexes in membranous nephropathy

The most characteristic feature of membranous nephropathy (MN) is the presence of subepithelial electron dense deposits and the consequential thickening of the glomerular basement membrane. There have been great advances in the understanding of the destiny of immune complexes in MN by the benefit of experimental models represented by Heymann nephritis. Subepithelial immune complexes are formed in situ by autoantibodies targeting native autoantigens or exogenous planted antigens such as the phospholipase A2 receptor (PLA2R) and cationic BSA respectively. The nascent immune complexes would not be pathogenic until they develop into immune deposits. Podocytes are the major source of autoantigens in idiopathic membranous nephropathy. They also participate in the modulation and removal of the immune complexes to a large extent. The balance between deposition and clearance is regulated by a wide range of factors such as the composition and physicochemical properties of the immune complexes and the complement system. Complement components such as C3 and C1q have been reported to be precipitated with the deposits whereas a complement regulatory protein CR1 expressed by podocytes is involved in the phagocytosis of immune complexes by podocytes. Podocytes regulate the dynamic change of immune complexes which is disturbed in membranous nephropathy. To elucidate the precise fate of the immune complexes is essential for developing more rational and novel therapies for membranous nephropathy.

Role of histone deacetylase inhibitors in non-neoplastic diseases

Background

Epigenetic dysregulation has been implicated in the development and progression of a variety of human diseases, but epigenetic changes are reversible, and epigenetic enzymes and regulatory proteins can be targeted using small molecules. Histone deacetylase inhibitors (HDACis), as a class of epigenetic drugs, are widely used to treat various cancers and other diseases involving abnormal gene expression.

Results

Specially, HDACis have emerged as a promising strategy to enhance the therapeutic effect of non-neoplastic conditions, including neurological disorders, cardiovascular diseases, renal diseases, autoimmune diseases, inflammatory diseases, infectious diseases and rare diseases, along with their related mechanisms. However, their clinical efficacy has been limited by drug resistance and toxicity.

Conclusions

To date, most clinical trials of HDAC inhibitors have been related to the treatment of cancer rather than the treatment of non-cancer diseases, for which experimental studies are gradually underway. Discussions regarding non-neoplastic diseases often concentrate on specific disease types. Therefore, this review highlights the development of HDACis and their potential therapeutic applications in non-neoplastic diseases, either as monotherapy or in combination with other drugs or therapies.

Genetic association between membranous nephropathy and malignancies: a two-sample Mendelian randomisation study

BACKGROUND

Various studies have reported that individuals with membranous nephropathy (MN) exhibit an elevated susceptibility to cancers. However, a causal relationship has not been clearly established.

METHODS

We constructed a genetic score that predicts MN by utilizing genetic variants linked to this condition as instrumental variables. These genetic scores were then compared with lung, colon, breast, and prostate cancer risks by a two-sample Mendelian randomisation analysis involving the following methods: MR-Egger, weighted median, inverse variance weighted, simple mode, and weighted mode.

RESULTS

This study demonstrated a lack of empirical substantiation for a causal association between genetic variants in MN and the susceptibility to lung, colon, prostate, or breast cancer.

CONCLUSION

Overall, we did not detect a causal link between MN and lung, colon, breast, or prostate cancer. Hence, additional research is imperative to elucidate the underlying factors contributing to the heightened occurrence of tumour in patients with MN.

Anti-Phospholipase A2 Receptor 1 and Anti-Cysteine Rich Antibodies, Domain Recognition and Rituximab Efficacy in Membranous Nephropathy: A Prospective Cohort Study

RATIONALE & OBJECTIVE

Proteinuria and anti-phospholipase A2 receptor 1 (anti-PLA2R1) antibody titers are associated with primary membranous nephropathy (MN) outcomes. We evaluated the association of antibodies against the cysteine-rich (CysR) and C-type lectin 1, 7, and 8 (CTLD1, CTLD7, and CTLD8) domains of PLA2R1 with MN outcomes.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

One-hundred-thirteen consecutive, consenting patients referred to the Nephology Unit of the Azienda-Socio-Sanitaria-Territoriale (ASST) Papa Giovanni XXIII (Bergamo, Italy) with PLA2R1-related, biopsy-proven MN whose persistent nephrotic syndrome (NS) was managed conservatively for>6 months and were monitored with serial evaluations of proteinuria, autoantibodies (by enzyme-linked immunosorbent assay), and clinical outcomes.

EXPOSURE

Rituximab.

OUTCOME

Complete (proteinuria<0.3g/24h) or partial (proteinuria≥0.3g/24h and<3.0g/24h with>50% reduction vs basal) NS remission.

ANALYTICAL APPROACH

Univariable and multivariable Cox regression analyses.

RESULTS

All patients had anti-CysR antibodies; 62 (54.9%) were multidomain recognizers. Anti-PLA2R1 and anti-CysR antibody titers were strongly correlated at baseline (P<0.001, r=0.934), 6 months (P<0.001, r=0.964), and 12 months (P<0.001, r=0.944). During a median follow-up of 37.1 (IQR, 20.3-56.9) months, 71 patients (62.8%) achieved either complete or partial remission of their NS. Lower baseline anti-PLA2R1 (HR, 0.997 [95% CI, 0.996-0.999], P=0.002) and anti-CysR [HR, 0.996 [95% CI, 0.993-0.998], P=0.001) titers were associated with a higher probability of remission, along with female sex, lower proteinuria, and lower serum creatinine levels (P<0.05 for all comparisons). Anti-CTLD antibodies were not associated with outcomes. At 6 and 12 months, compared to baseline, anti-PLA2R1 and anti-CysR antibody titers decreased more in patients progressing to partial or complete remission than in those without remission (P<0.05 for all comparisons).

LIMITATIONS

Observational design.

CONCLUSIONS

In PLA2R1-related MN, anti-PLA2R1 and anti-CysR antibodies similarly predict rituximab efficacy independent of PLA2R1 domain recognition. The choice between these tests should be dictated by feasibility and costs. Evaluating anti-CTLD antibodies appears unnecessary.

PLAIN-LANGUAGE SUMMARY

Primary membranous nephropathy (MN), a leading cause of nephrotic syndrome (NS) in adults, is an autoimmune disease caused by autoantibodies binding to the podocyte antigen phospholipase A2 receptor 1 (PLA2R1). We assessed whether the effects of anti-CD20 cytolytic therapy with the monoclonal antibody rituximab are associated with detection rates and levels of anti-PLA2R1 antibodies and antibodies against PLA2R1 domains such as cysteine-rich (CysR), and C-type lectin 1, 7, and 8 (CTLD1, 7, and 8), in patients with PLA2R1-related MN and persistent NS. The probability of rituximab-induced complete or partial NS remission was associated with baseline anti-PLA2R1 and anti-CysR antibody titers, but not with anti-CTLD1, 7 and 8 antibodies or multidomain recognition. Integrated evaluation of anti-PLA2R1 or anti-CysR antibodies with proteinuria and kidney function may play a role in monitoring the effects of rituximab in patients with PLA2R1-related NS and MN.

Primary membranous nephropathy in the Italian region of Emilia Romagna: results of a multicenter study with extended follow-up

BACKGROUND

Since primary membranous nephropathy is a heterogeneous disease with variable outcomes and multiple possible therapeutic approaches, all 13 Nephrology Units of the Italian region Emilia Romagna decided to analyze their experience in the management of this challenging glomerular disease.

METHODS

We retrospectively studied 205 consecutive adult patients affected by biopsy-proven primary membranous nephropathy, recruited from January 2010 through December 2017. The primary outcome was patient and renal survival. The secondary outcome was the rate of complete remission and partial remission of proteinuria. Relapse incidence, treatment patterns and adverse events were also assessed.

RESULTS

Median (IQR) follow-up was 36 (24-60) months. Overall patient and renal survival were 87.4% after 5 years. At the end of follow-up, 83 patients (40%) had complete remission and 72 patients (35%) had partial remission. Among responders, less than a quarter (23%) relapsed. Most patients (83%) underwent immunosuppressive therapy within 6 months of biopsy. A cyclic regimen of corticosteroid and cytotoxic agents was the most commonly used treatment schedule (63%), followed by rituximab (28%). Multivariable analysis showed that the cyclic regimen significantly correlates with complete remission (odds ratio 0.26; 95% CI 0.08-0.79) when compared to rituximab (p < 0.05).

CONCLUSIONS

In our large study, both short- and long-term outcomes were positive and consistent with those published in the literature. Our data suggest that the use of immunosuppressive therapy within the first 6 months after biopsy appears to be a winning strategy, and that the cyclic regimen also warrants a prominent role in primary membranous nephropathy treatment, since definitive proof of rituximab superiority is lacking.

Ofatumumab in Rituximab-Resistant and Rituximab-Intolerant Patients With Primary Membranous Nephropathy: A Case Series

RATIONALE & OBJECTIVE

Rituximab is the first-choice therapy for patients with primary membranous nephropathy (MN) and nephrotic syndrome. However, approximately 30% of patients are treatment-resistant or become treatment-intolerant with hypersensitivity reactions upon repeated drug exposures. We aimed to assess whether ofatumumab, a fully human second-generation anti-CD20 antibody, could be a valuable alternative to rituximab in this population.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

7 rituximab-intolerant and 10 rituximab-resistant patients with MN who consented to receive ofatumumab (50-300mg, single intravenous infusion) and were followed at the nephrology unit of Azienda Socio-Sanitaria Territoriale Papa Giovanni XXIII (Bergamo, Italy) between September 2015 and January 2019.

FINDINGS

Over a median (IQR) follow-up of 5.0 (3.0-9.8) months, all 7 rituximab-intolerant and 3 of the 10 rituximab-resistant patients exhibited complete (proteinuria<0.3g/d) or partial (proteinuria<3.5g/d with≥50% reduction vs baseline) remission of nephrotic syndrome. Circulating B cells were similarly depleted in all patients by 1 week, and serum anti-phospholipase A2 receptor antibody concentrations decreased to<2.7 relative units/mL in 3 of 4 rituximab-intolerant and 4 of 8 rituximab-resistant patients with phospholipase A2 receptor-related disease. Ofatumumab significantly reduced 24-hour urinary protein and immunoglobulin G excretion and increased serum albumin and immunoglobulin G levels. These effects were greater in rituximab-intolerant than in rituximab-resistant patients. Measured glomerular filtration rate significantly increased by an average of 13.4% at 24 months compared with baseline (P=0.036) among all patients in the series. There were 14 nonserious infusion-related adverse events in 9 patients that recovered with temporary infusion interruption.

LIMITATIONS

Retrospective design, limited number of patients.

CONCLUSIONS

Ofatumumab may represent an effective and safe treatment for rituximab-intolerant cases of MN. Larger prospective studies will be needed to validate these preliminary findings and explore the effectiveness of other second-generation anti-CD20 antibodies in this clinical setting.

PLAIN-LANGUAGE SUMMARY

Primary membranous nephropathy (MN) is one of the most frequent causes of nephrotic syndrome (NS) in adults. In this case series, we explored the efficacy of ofatumumab, a fully human second-generation anti-CD20 antibody, in 17 patients with MN and NS who were intolerant or unresponsive to rituximab. All 7 rituximab-intolerant patients exhibited complete or partial clinical remission, compared with only 3 of the 10 rituximab-resistant patients. Autoantibody levels decreased in all patients with phospholipase A2 receptor-related disease. Ofatumumab achieved a significant reduction in urinary protein and immunoglobulin G excretion while increasing serum albumin and immunoglobulin G levels. Ofatumumab may be a promising option for patients with MN who are rituximab-intolerant. Further investigations are warranted to validate these preliminary findings.

Bi-specific autoantigen-T cell engagers as targeted immunotherapy for autoreactive B cell depletion in autoimmune diseases

Introduction

In autoimmune diseases, autoreactive B cells comprise only the 0.1-0.5% of total circulating B cells. However, current first-line treatments rely on non-specific and general suppression of the immune system, exposing patients to severe side effects. For this reason, identification of targeted therapies for autoimmune diseases is an unmet clinical need.

Methods

Here, we designed a novel class of immunotherapeutic molecules, Bi-specific AutoAntigen-T cell Engagers (BiAATEs), as a potential approach for targeting the small subset of autoreactive B cells. To test this approach, we focused on a prototype autoimmune disease of the kidney, membranous nephropathy (MN), in which phospholipase A2 receptor (PLA2R) serves as primary nephritogenic antigen. Specifically, we developed a BiAATE consisting of the immunodominant Cysteine-Rich (CysR) domain of PLA2R and the single-chain variable fragment (scFv) of an antibody against the T cell antigen CD3, connected by a small flexible linker.

Results

BiAATE creates an immunological synapse between autoreactive B cells bearing an CysR-specific surface Ig+ and T cells. Ex vivo, the BiAATE successfully induced T cell-dependent depletion of PLA2R-specific B cells isolated form MN patients, sparing normal B cells. Systemic administration of BiAATE to mice transgenic for human CD3 reduced anti-PLA2R antibody levels following active immunization with PLA2R.

Discussion

Should this approach be confirmed for other autoimmune diseases, BiAATEs could represent a promising off-the-shelf therapy for precision medicine in virtually all antibody-mediated autoimmune diseases for which the pathogenic autoantigen is known, leading to a paradigm shift in the treatment of these diseases.

Comparative pharmacoeconomic analysis of rituximab and traditional tacrolimus regimens in membranous nephropathy in China

Background: Rituximab (RTX) is a monoclonal antibody that selectively targets CD20 and is frequently used in the treatment of membranous nephropathy (MN). Analysis of the therapeutic efficacy and safety of RTX in treating MN in practice and a comparative pharmacoeconomic analysis of the RTX and traditional tacrolimus (TAC) regimens can provide valuable insights to aid decision-making by the government and relevant medical insurance departments. Methods: We conducted a statistical analysis of medical records from patients diagnosed with MN who underwent RTX treatment between 1 January 2019 and 1 January 2023. The TAC data were obtained from the clinical literature. The efficacy rates and incidence of adverse effects (AEs) were calculated to compare the efficacy and safety of RTX and TAC. Based on the patient's disease status, we developed a Markov model to compare the total cost, remission rate, and incremental cost-effectiveness ratio (ICER) of the two regimens. Both univariate and probability sensitivity analyses were performed to validate the stability of the developed model. Results: The RTX group enrolled 53 patients with MN, and the 12-month overall efficacy rate was not significantly different from that of the TAC group with 35 patients (86.79% vs. 71.4%, p = 0.0131); however, the relapse rate was significantly lower in the RTX group (3.77% vs. 22.8%, p = 0.016). The RTX group demonstrated no severe AEs (SAEs), while the TAC group demonstrated six cases of SAEs, including 4 cases of severe pneumonia, 1 case of lung abscess and 1 case of interstitial lung disease, accounting for 7.89% of traditional tacrolimus-treated patients. The baseline analysis results revealed that over a 5-year post-treatment period, RTX increased quality-adjusted life years (QALYs) by 0.058 and costs by ¥7,341. Assuming three times the 2022 domestic gross domestic product as the willingness-to-pay (WTP) threshold per QALY, the ICER of RTX compared to TAC was ¥124,631.14/QALY, which is less than the WTP threshold of ¥257,094/QALY, indicating that RTX treatment is approximately two times more cost-effective compared to TAC. Conclusion: The current analysis indicates that despite the expensive unit price of RTX, it remains a cost-effective treatment option for MN compared to TAC.

Expression and Clinical Significance of Non B Cell-Derived Immunoglobulins in the Urinary System and Male Reproductive System

The urinary system comprises kidneys, ureters, bladder, and urethra with its primary function being excretion, referring to the physiological process of transporting substances that are harmful or surplus out of the body. The male reproductive system consists of gonads (testis), vas deferens, and accessory glands such as the prostate. According to classical immunology theory, the tissues and organs mentioned above are not thought to produce immunoglobulins (Igs), and any Ig present in the relevant tissues under physiological and pathological conditions is believed to be derived from B cells. For instance, most renal diseases are associated with uncontrolled inflammation caused by pathogenic Ig deposited in the kidney. Generally, these pathological Igs are presumed to be produced by B cells. Recent studies have demonstrated that renal parenchymal cells can produce and secrete Igs, including IgA and IgG. Glomerular mesangial cells can express and secrete IgA, which is associated with cell survival and adhesion. Likewise, human podocytes demonstrate the ability to produce and secrete IgG, which is related to cell survival and adhesion. Furthermore, renal tubular epithelial cells also express IgG, potentially involved in the epithelial-mesenchymal transition (EMT). More significantly, renal cell carcinoma, bladder cancer, and prostate cancer have been revealed to express high levels of IgG, which promotes tumour progression. Given the widespread Ig expression in the urinary and male reproductive systems, continued efforts to elucidate the roles of Igs in renal physiological and pathological processes are necessary.

Cyclophosphamide ameliorates membranous nephropathy by upregulating miR-223 expression, promoting M2 macrophage polarization and inhibiting inflammation

BACKGROUND

Membranous nephropathy (MN), also known as membranous glomerulonephritis, is a leading cause of adult nephrotic syndrome. The main pathological features encompass the deposition of immune complexes within the glomerular basement membrane epithelial cells, thickening of the basement membrane, and fusion of the foot process.

OBJECTIVE

This study aims to investigate the role of the immune and inflammatory modulator miR-223 in the immunosuppressive and anti-inflammatory effects of cyclophosphamide (CTX) on membranous nephropathy (MN).

METHODS

miR-223 mimetics or inhibitors was used to regulate miR-223 levels. LPS induced inflammatory cell model and cell polarization. CTX was used to treat Lipopolysaccharides (LPS) induced inflammatory response and polarization. Cationic bovine serum albumin (c-BSA) induced BALB/c mouse MN model, while CTX was used to treat c-BSA induced MN.

RESULTS

The miR-223 level in LPS induced inflammatory model cells was lower than that in control cells. The levels of inflammatory factors in LPS+miR-223 mimetics and CTX+miR-223i cells were lower than those in LPS and miR-223i cells. The protein levels of LPS+miR-223 mimic, CTX+miR-223i macrophage M2 phenotype markers Arginase-1 (Arg1), transforming growth factor β1 (TGF-β1), anti-inflammatory factors interleukin-4 (IL4) and interleukin-13 (IL13) were significantly higher than those of LPS and miR-223i. The effect of CTX was confirmed in a BALB/c mouse MN model induced by cationic bovine serum albumin (c-BSA).

CONCLUSION

CTX upregulates the expression of miR-223, promotes polarization of M2 macrophages, alleviates the inflammatory response and renal injury of MN.

Combination of rituximab and short-term glucocorticoids in the treatment of anti-phospholipase A2 receptor antibody positive idiopathic membranous nephropathy

Rituximab (RTX) has been the first option in idiopathic membranous nephropathy (IMN). However, the clinical effect was not very satisfactory. This study aimed to explore the clinical efficacy and safety of the combination of RTX and glucocorticoids (GC) in anti-phospholipase A2 receptor (anti-PLA2R) antibody positive IMN. Sixty-six patients were randomly divided into RTX/GC group (RTX infusion plus short-term oral GC) and RTX group (RTX infusion alone) in this prospective cohort study. Complete remission (CR) and partial remission (PR) were the primary outcomes. Adverse events were the secondary outcomes. The laboratory index including serum albumin, 24 h urinary protein, serum creatinine, estimated glomerular filtration rate, and anti-PLA2R antibody titer were also monitored. All patients were followed for at least 12 months. During the 12-month follow-up, the composite remission rates in RTX/GC and RTX groups were 74.3% and 67.7%, and the CR rates were 34.3% and 19.4%, respectively. The median time of remission in RTX/GC group was shorter than the RTX group (P < 0.001). Compared with RTX monotherapy, the combination of RTX and GC significantly decreased the anti-PLA2R antibody titer (P = 0.028). No significant difference was observed in the incidence of adverse events. The results of the Kaplan-Meier survival analysis indicated that the cumulative CR rate and cumulative composite remission rate in RTX/GC group were all better than the RTX group (P = 0.043, P = 0.040, respectively). The combination of RTX and GC was better than RTX monotherapy without increasing the adverse events in the treatment of IMN.

Identification of biomarkers related to immune and inflammation in membranous nephropathy: comprehensive bioinformatic analysis and validation

Background

Membranous nephropathy (MN) is an autoimmune glomerular disease that is predominantly mediated by immune complex deposition and complement activation. The aim of this study was to identify key biomarkers of MN and investigate their association with immune-related mechanisms, inflammatory cytokines, chemokines and chemokine receptors (CCRs).

Methods

MN cohort microarray expression data were downloaded from the GEO database. Differentially expressed genes (DEGs) in MN were identified, and hub genes were determined using a protein-protein interaction (PPI) network. The relationships between immune-related hub genes, immune cells, CCRs, and inflammatory cytokines were examined using immune infiltration analysis, gene set enrichment analysis (GSEA), and weighted gene co-expression network analysis (WGCNA). Finally, the immune-related hub genes in MN were validated using ELISA.

Results

In total, 501 DEGs were identified. Enrichment analysis revealed the involvement of immune- and cytokine-related pathways in MN progression. Using WGCNA and immune infiltration analysis, 2 immune-related hub genes (CYBB and CSF1R) were identified. These genes exhibited significant correlations with a wide range of immune cells and were found to participate in B cell/T cell receptor and chemokine signaling pathways. In addition, the expressions of 2 immune-related hub genes were positively correlated with the expression of CCR1, CX3CR1, IL1B, CCL4, TNF, and CCR2.

Conclusion

Our study identified CSF1 and CYBB as immune-related hub genes that potentially influence the expression of CCRs and pro-inflammatory cytokines (CCR1, CX3CR1, IL1B, CCL4, TNF, and CCR2). CSF1 and CYBB may be potential biomarkers for MN progression, providing a perspective for diagnostic and immunotherapeutic targets of MN.

Cyclophosphamide induced early remission and was superior to rituximab in idiopathic membranous nephropathy patients with high anti-PLA2R antibody levels

Rituximab (RTX) and cyclophosphamide (CYC) based treatments are both recommended as first-line therapies in idiopathic membranous nephropathy (IMN) by KDIGO 2021 guideline. However, the efficacy of RTX vs. CYC-based treatments in IMN is still controversial. We performed this systemic review and meta-analysis registered in PROSPERO (CRD 42,022,355,717) by pooling data from randomized controlled trials or cohort studies in IMN patients using the EMBASE, PubMed, and Cochrane libraries (till Orc 1, 2022). The primary outcomes were the complete remission (CR) rate + partial remission (PR) rate. CR rate, immunologic response rate, relapse rate, and the risk of serious adverse events (SAE) were secondary outcomes. Eight studies involving 600 adult patients with IMN were included with a median follow-up duration of 12 to 60 months. RTX induced a similar overall remission rate compared with CYC (RR 0.88, 95% CI: 0.71, 1.09, P = 0.23). At the follow-up time of 6 months, RTX was associated with a lower CR + PR rate compared with CYC (RR 0.67, 95% CI: 0.52, 0.88, P = 0.003). Moreover, RTX might be less effective in inducing CR + PR than CYC treatment in IMN patients with high antiPLA2R antibody levels (RR 0.67, 95% CI: 0.48, 0.94, P = 0.02). The occurrences of CRs, relapse rates, immunologic response rates, and SAE were not significantly different between RTX and CYC, respectively. In conclusion, although the long-term efficacy and safety of CYC compared to RTX were comparable, CYC might respond faster and be more advantageous in IMN patients with high antiPLA2R antibody titers.

Future landscape for the management of membranous nephropathy

Among all glomerular diseases, membranous nephropathy (MN) is perhaps the one in which major progress has been made in recent decades, in both the understanding of the pathogenesis and treatment. Despite the overall significant response rates to these therapies-particularly rituximab and cyclical regimen based on corticosteroids and cyclophosphamide-cumulative experience over the years has shown, however, that 20%-30% of cases may confront resistant disease. Thus, these unmet challenges in the treatment of resistant forms of MN require newer approaches. Several emerging new agents-developed primarily for the treatment of hematological malignancies or rheumatoid diseases-are currently being evaluated in MN. Herein we conducted a narrative review on future therapeutic strategies in the disease. Among the different novel therapies, newer anti-CD20 agents (e.g. obinutuzumab), anti-CD38 (e.g. daratumumab, felzartamab), immunoadsorption or anti-complement therapies (e.g. iptacopan) have gained special attention. In addition, several technologies and innovations developed primarily for cancer (e.g. chimeric antigen receptor T-cell therapy, sweeping antibodies) seem particularly promising. In summary, the future therapeutic landscape in MN seems encouraging and will definitely move the management of this disease towards a more precision-based approach.

Membranous nephropathy: Mechanistic insights and therapeutic perspectives

Membranous nephropathy (MN) is one of the most common causes of non-diabetic nephrotic syndrome in adults. About 80% of cases are renal limited (primary MN) and 20% are associated with other systemic diseases or exposures (secondary MN). Autoimmune reaction is the main pathogenic factor of MN, and the discovery of autoantigens including the phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A has led to new insights into the pathogenesis, they can induce humoral immune responses led by IgG4 makes them suitable for the diagnosis and monitoring of MN. In addition, complement activation, genetic susceptibility genes and environmental pollution are also involved in MN immune response. In clinical practice, due to the spontaneous remission of MN, the combination of supportive therapy and pharmacological treatment is widely used. Immunosuppressive drugs are the cornerstone of MN treatment, and the dangers and benefits of this approach vary from person to person. In summary, this review provides a more comprehensive review of the immune pathogenesis, interventions and unresolved issues of MN in the hope of providing some new ideas for clinical and scientific researchers in the treatment of MN.

Evaluation of the immune checkpoint factors in idiopathic membranous nephropathy

Idiopathic membranous nephropathy (IMN), a single-organ autoimmune disease, is recognized by autoantibodies to podocyte proteins and identified as the most frequent cause of nephrotic syndrome in adults. T cells are important contributors in autoimmunity since they promote B-cell development, antibody production, direct inflammation, and organ tissue cytotoxicity. This study investigated the inhibitory immune checkpoint (ICP) receptors expressed on T lymphocytes and other immune cells. Thus, PBMCs from IMN patients were obtained before treatment, and the levels of ICPs such as programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), lymphocyte activation gene-3 (LAG-3), and T cell immunoglobulin-3 (TIM-3) were examined at both gene and protein expression using real time PCR and Western blot tests respectively. The results illustrated that gene expression levels of ICPs reduced significantly in comparison to the control which were verified by related fold changes of protein expression sequentially. Our study revealed that CTLA-4, PD-1, TIM-3, and LAG-3 expression is impaired in IMN patients before treatment which could be a potential target for therapy.

Immunosuppressive therapy for progressive idiopathic membranous nephropathy: a cost-effectiveness analysis in China

BACKGROUND

This study aims to evaluate the cost-effectiveness of immunosuppressive therapy for patients with progressive idiopathic membranous nephropathy (IMN) from the Chinese healthcare system perspective.

METHODS

To estimate the cost-effectiveness of four regimens namely cyclophosphamide, cyclosporine, rituximab and tacrolimus-rituximab in treatment of IMN recommended by the updated Kidney Disease: Improving Global Outcomes (KDIGO) guideline 2021, a Markov model with five discrete states (active disease, remission, dialysis, kidney transplant and death) based on IMN patients aged 50 or above over a 30-years time horizon was constructed. Total costs were imputed from the Chinese healthcare system perspective, and health outcomes were converted into quality-adjusted life years (QALYs). The incremental cost-effectiveness ratio (ICER) was used to describe the results. The willingness-to-pay (WTP) threshold was set at $12,044 (China's 2021 Gross Domestic Product per capita). Sensitivity analyses were performed to test the uncertainties of the results.

RESULT

Compared with cyclophosphamide, both cyclosporine (incremental cost $28,337.09, incremental QALY-1.63) and tacrolimus-rituximab (incremental cost $28,324.13, incremental QALY -0.46) were considered at strictly dominated for their negative values in QALYs, and the ICER value of rituximab was positive (incremental cost $9,162.19, incremental QALY 0.44). Since the ICER of rituximab exceeds the pre-determined threshold, cyclophosphamide was likely to be the best choice for the treatment of IMN within the acceptable threshold range. The results of the sensitivity analysis revealed that the model outcome was mostly affected by the probability of remission in rituximab. In a probabilistic sensitivity analysis, cyclophosphamide had 62.4% probability of being cost-effective compared with other regimens when the WTP was $12,044 per QALY. When WTP exceeded $18,300, rituximab was more cost-effective than cyclophosphamide.

CONCLUSION

Compared with cyclosporine, rituximab and tacrolimus-rituximab, our model results indicated that cyclophosphamide represented the most cost-effective regimen for patients with progressive IMN in China.

Update on the Application of Monoclonal Antibody Therapy in Primary Membranous Nephropathy

When first introduced, rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, brought about an alternative therapeutic paradigm for primary membranous nephropathy (PMN). Rituximab was shown to be effective and safe in PMN patients with kidney dysfunction, with. patients receiving second-line rituximab therapy achieving remission as effectively as those patients who had not previously received immunotherapy. No safety issues were reported. The B cell-driven protocol seems to be as efficient as the 375 mg/m² × 4 regimen or 1 g × 2 regimen in achieving B cell depletion and remission, but patients with high M-type phospholipase A2 receptor (PLA2R) antibody levels may benefit from a higher dose of rituximab. While rituximab added another therapeutic option to the treatment regimen, it does have limitations as 20 to 40% of patients do not respond. Not all patients respond to RTX therapy for lymphoproliferative disorders either, therefore further novel anti-CD20 monoclonal antibodies have been developed and these may provide alternative therapeutic options for PMN. Ofatumumab, a fully human monoclonal antibody, specifically recognizes an epitope encompassing both the small and large extracellular loops of the CD20 molecule, resulting in increased complement-dependent cytotoxic activity. Ocrelizumab binds an alternative but overlapping epitope region to rituximab and displays enhanced antibody-dependent cellular cytotoxic (ADCC) activities. Obinutuzumab is designed to have a modified elbow-hinge amino acid sequence, leading to increased direct cell death induction and ADCC activities. In PMN clinical studies, ocrelizumab and obinutuzumab showed promising results, while ofatumumab displayed mixed results. However, there is a lack of randomized controlled trials with large samples, especially direct head-to-head comparisons. Alternative molecular mechanisms have been suggested in this context to explore novel therapeutic strategies. B cell activator-targeted, plasma cell-targeted and complement-directed treatments may lead to novel therapy paradigms for PMN. Exploratory strategies for the use of drugs with different mechanisms, such as a combination of rituximab and cyclophosphamide and a steroid, a combination of rituximab and a calcineurin inhibitor, may provide more rapid and efficient remission, but the combination of standard immunosuppression with rituximab could increase infection risk.

The characters of antibodies against PLA2R in healthy individuals and in the patient with PLA2R associated membranous nephropathy

BACKGROUND

Most primary membranous nephropathy (MN) is mediated by anti-phospholipase A2 receptor (PLA2R) antibodies. Recently, these antibodies have been revealed months to years before the disease's onset. Their production and pathogenicity need further investigation.

METHODS

Anti-PLA2R antibodies were purified from plasma of eight healthy individuals, 12 patients with PLA2R-related MN and negative circulating antibody (Ab-), and 18 patients with positive anti-PLA2R antibodies (Ab +), using affinity column coupled with recombinant human PLA2R. The antigen specificity, antibody amount, titer, IgG subclass, and affinity were assessed by Western blot, immunofluorescence, ELISA, and surface plasmon resonance.

RESULTS

The natural anti-PLA2R antibodies recognized the conformational structure of PLA2R which locates on the cell membrane of podocytes. The amount of natural IgG was 0.12 ± 0.04 g/L, which accounted for 0.80% of total IgG and was lower than that of patients (2.36%, P < 0.001). The titer of natural antibodies was lower than that of patients in Ab- and Ab + groups (1:16 vs. 1:43 vs. 1:274, P < 0.001). IgG2(45.1%) was predominant in natural antibodies, while IgG4 was predominant in Ab + group (45.7 vs. 25.0%, P < 0.001). IgG1 was increasing from natural antibodies to Ab- and Ab + groups. The affinity of natural antibodies was lower than that of patients (K_D: 641.0 vs. 269.0 vs. 99.6 nM, P = 0.002). The antibody titer, affinity, and IgG4 percentage were associated with the severity of proteinuria and the stages of membranous lesion.

CONCLUSIONS

The natural anti-PLA2R antibodies exist in healthy plasma. The antibody titer, IgG subclass, and affinity may participate in the pathogenesis of anti-PLA2R antibodies.

Immunosuppressive Agent Options for Primary Nephrotic Syndrome: A Review of Network Meta-Analyses and Cost-Effectiveness Analysis

Therapeutic options with immunosuppressive agents for glomerular diseases have widened with refinements to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines from 2012 to 2021. However, international guidelines do not necessarily match the reality in each country. Expensive therapies such as rituximab and calcineurin inhibitors are sometimes inaccessible to patients with refractory nephrotic syndrome due to cost or regulations. Under the Japanese medical insurance system, rituximab is accessible but still limited to steroid-dependent patients who developed idiopathic nephrotic syndrome in childhood. Based on international KDIGO guidelines and other national guidelines, possible applications of immunosuppressive agents for nephrotic syndrome are comprehensively examined in this review. While rituximab has become the mainstay of immunosuppressive therapy for nephrotic syndrome, clinical trials have indicated that options such as cyclophosphamide, calcineurin inhibitors, and mycophenolate mofetil would be preferable. Given the rising number of patients with nephrotic syndrome worldwide, KDIGO guidelines mention the need for further consideration of cost-effectiveness. If the new option of rituximab is to be the first choice in combination with steroids for nephrotic syndrome, its cost-effectiveness should also be verified. Among the few studies examining the cost-effectiveness of treatments for nephrotic syndrome, administration of rituximab to young adults has been shown to be cost-beneficial, at least in Japan. However, further large-scale studies involving multiple facilities are needed to verify such findings. Network meta-analyses have concluded that the efficacy of rituximab remains controversial and confirmation through high-quality studies of large cohorts is needed. To this end, the mechanisms of action underlying immunosuppressive agents, both old and new, need to be understood and experience must be accumulated to evaluate possible effects and side effects.

Mapping the T cell epitopes of the M-type transmembrane phospholipase A2 receptor in primary membranous nephropathy

The M-type phospholipase A2 receptor (PLA2R) is the major autoantigen of primary membranous nephropathy (MN). Despite many studies on B-cell epitopes recognized by antibodies, little is known about T-cell epitopes. Herein, we synthesized 123 linear peptides, each consisting of 15-22 amino acids with 8-12 amino acid overlaps, across ten domains of PLA2R. Their binding capacity to risk (DRB1∗1501, DRB1∗0301) and protective (DRB1∗0901, DRB1∗0701) HLA molecules was then assessed by flow cytometry. Proliferation of CD4+ T cells from patients with anti-PLA2R positive MN was analyzed after peptide stimulation. Cytokines produced by activated peripheral blood mononuclear cells were measured by cytometric bead arrays. We identified 17 PLA2R peptides that bound to both DRB1∗1501 and DRB1∗0301 molecules with high capacity. Some of these peptides showed decreased binding to heterozygous DRB1∗1501/0901 and DRB1∗0301/0701. Ten of the 17 peptides (CysR1, CysR10, CysR12, FnII-3, CTLD3-9, CTLD3-10, CTLD3-11, CTLD5-2-1, CTLD7-1 and CTLD7-2) induced significant proliferation of CD4+ T cells from patients with MN than cells from healthy individuals. Upon activation by these peptides, peripheral blood mononuclear cells from patients with MN produced higher levels of pro-inflammatory cytokines, predominantly IL-6, TNF-α, IL-10, IL-9 and IL-17. Thus, we mapped and identified ten peptides in the CysR, FnII, CTLD3, CTLD5, and CTLD7 domains of PLA2R as potential T-cell epitopes of MN. These findings are a first step towards developing peptide-specific immunotherapies.

Efficacy and safety of rituximab for primary membranous nephropathy with different clinical presentations: a retrospective study

Background

Rituximab (RTX) is gaining increasing clinical acceptance in the treatment of primary membranous nephropathy (PMN), with demonstrated efficacy and safety. However, there are few clinical studies on RTX for PMN in Asian populations, especially in China.

Methods

To observe and analyse the efficacy and safety of RTX treatment, 81 patients with PMN suffering from nephrotic syndrome (NS) were enrolled and divided into an initial therapy group, a conventional immunosuppressive therapy relapse group, and a conventional immunosuppressive therapy ineffective group according to their pre-RTX treatment background. Patients in each group were followed up for 12 months. The primary outcome was clinical remission at 12 months, and the secondary outcomes were safety and the occurrence of adverse events.

Results

At 12 months, 65 of 81 (80.2%) patients achieved complete (n=21, 25.9%) or partial (n=44, 54.3%) remission after rituximab treatment. Thirty-two of 36 (88.9%) patients in the initial therapy group, 11 of 12 (91.7%) patients in the relapse group and 22 of 33 (66.7%) patients in the ineffective group achieved clinical remission. All 59 patients with positive anti-PLA2R antibodies showed a decreasing trend in antibody levels after RTX treatment, and 55 (93.2%) of them achieved antibody clearance (<20 U/mL). Logistic regression analysis showed that a high anti-PLA2R antibody titer (OR=0.993, P=0.032) was an independent risk factor for nonremission. Adverse events occurred in 18 (22.2%) patients, of which 5 (6.2%) were serious adverse events, and none were malignant or otherwise fatal.

Conclusion

RTX alone can effectively induce remission PMN and maintain stable renal function. It is recommended as the first choice of treatment and is also effective in patients who relapse and have poor responses to conventional immunosuppressive therapy. Anti-PLA2R antibodies can be used as a marker for RTX treatment monitoring, and antibody clearance is necessary to achieve and improve the rates of clinical remission.

Review of the Role of Rituximab in the Management of Adult Minimal Change Disease and Immune-Mediated Focal and Segmental Glomerulosclerosis

Background

Minimal change disease and primary FSGS are podocytopathies but are also immune-mediated diseases. Rituximab acts via multiple mechanisms by tilting the balance between autoreactive B and T cells in favor of regulatory B and T cells. The consequences are decreased production of cytokines, chemokines, and permeability factors by these cells. In the past decade, we have seen the discovery of autoantibodies mediating nephrotic syndrome (anti-annexin A2 antibody, anti-UCHL1 antibody, and anti-nephrin antibody), and rituximab decreases their production. Rituximab also binds to podocyte SMPDL3b and has direct podocyte actions.

Summary

Rituximab's role in managing these primary podocytopathies has been discussed in this brief review. Rituximab has been used extensively in children and adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, rituximab is not very promising in adult steroid-resistant nephrotic syndrome. Although ofatumumab would cause prolonged B-cell depletion and is fully humanized, it is unclear if it is superior to rituximab in preventing relapse of nephrotic syndrome.

Key Messages

Rituximab therapy can induce prolonged remission in adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, no good data exist on using rituximab in steroid-resistant nephrotic syndrome.

Membranous nephropathy: Clearer pathology and mechanisms identify potential strategies for treatment

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.

A Novel Mouse Model of Idiopathic Nephrotic Syndrome Induced by Immunization with the Podocyte Protein Crb2

BACKGROUND

The cause of podocyte injury in idiopathic nephrotic syndrome (INS) remains unknown. Although recent evidence points to the role of B cells and autoimmunity, the lack of animal models mediated by autoimmunity limits further research. We aimed to establish a mouse model mimicking human INS by immunizing mice with Crb2, a transmembrane protein expressed at the podocyte foot process.

METHODS

C3H/HeN mice were immunized with the recombinant extracellular domain of mouse Crb2. Serum anti-Crb2 antibody, urine protein-to-creatinine ratio, and kidney histology were studied. For signaling studies, a Crb2-expressing mouse podocyte line was incubated with anti-Crb2 antibody.

RESULTS

Serum anti-Crb2 autoantibodies and significant proteinuria were detected 4 weeks after the first immunization. The proteinuria reached nephrotic range at 9-13 weeks and persisted up to 29 weeks. Initial kidney histology resembled minimal change disease in humans, and immunofluorescence staining showed delicate punctate IgG staining in the glomerulus, which colocalized with Crb2 at the podocyte foot process. A subset of mice developed features resembling FSGS after 18 weeks. In glomeruli of immunized mice and in Crb2-expressing podocytes incubated with anti-Crb2 antibody, phosphorylation of ezrin, which connects Crb2 to the cytoskeleton, increased, accompanied by altered Crb2 localization and actin distribution.

CONCLUSION

The results highlight the causative role of anti-Crb2 autoantibody in podocyte injury in mice. Crb2 immunization could be a useful model to study the immunologic pathogenesis of human INS, and may support the role of autoimmunity against podocyte proteins in INS.

Idiopathic membranous nephropathy with renal amyloidosis: A case report

Background

Immunoglobulin light chain amyloidosis is a clonal, non-proliferative plasma cell disorder, in which fragments of immunoglobulin light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma. Membranous nephropathy (MN) is a group of diseases characterized by deposition of immune complexes under the epithelial cells of glomerular basement and diffuse thickening of the basement membrane. Most patients with idiopathic MN (IMN) have been exposed to phospholipase A2 receptor (PLA2R) antigen, and anti-PLA2R antibodies that attack podocytes can be detected in their blood. IMN combined with amyloidosis nephropathy without secondary factors is rare. The present study describes a patient with IMN combined with immunoglobulin light chain amyloidosis nephropathy.

Case report

A 39-year-old man was admitted to our hospital because of weight loss and edema. His clinical manifestation was nephrotic syndrome. Renal pathology revealed MN. A positive Congo red staining and the pathognomonic apple-green birefringence under cross-polarized light were considered to be associated with amyloid nephropathy. Immunofluorescence showed that λ light chain was positive. Heavy chain deposition disease and amyloid-associated protein amyloidosis were excluded by immunofluorescence and immunohistochemistry, respectively. Subsequent examinations showed that his serum was negative for antibodies against the PLA2R, but PLA2R was present in renal tissue. The final diagnosis was IMN with light chain amyloid nephropathy.

Conclusion

Renal amyloidosis accompanied by IMN is uncommon. Attention should be paid to the subtype of the disease and the exclusion of secondary factors. Perfect clinical and pathological examination are helpful for the classification and staging of the disease. Congo red staining, light microscopy, immunofluorescence, immunohistochemistry, electron microscopic examination, pathological tissue staining for PLA2R antigen and testing for anti-PLA2R antibody in serum are helpful.

Sexual dimorphic response to rituximab treatment: A longitudinal observational study in a large cohort of patients with primary membranous nephropathy and persistent nephrotic syndrome

Rituximab is one of the first-line therapies for patients with membranous nephropathy (MN) at high risk of progression towards kidney failure. We investigated whether the response to Rituximab was affected by sex and anti-PLA2R antibody levels in 204 consecutive patients (148 males and 56 females) with biopsy-proven MN who were referred to the Nephrology Unit of the Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII from March 2001 to October 2016 and managed conservatively for at least 6 months. The primary outcome was a combined endpoint of complete (proteinuria <0.3 g/24 h) or partial (proteinuria <3.0 g/24 h and >50% reduction vs. baseline) remission. Patients gave written informed consent to Rituximab treatment. The study was internally funded. No pharmaceutical company was involved. Anti-PLA2R antibodies were detectable in 125 patients (61.3%). At multivariable analyses, female gender (p = 0.0198) and lower serum creatinine levels (p = 0.0108) emerged as independent predictors of better outcome (p = 0.0198). The predictive value of proteinuria (p = 0.054) and anti-PLA2R titer (p = 0.0766) was borderline significant. Over a median (IQR) of 24.8 (12.0-36.0) months, 40 females (71.4%) progressed to the combined endpoint compared with 73 males (49.3%). Anti-PLA2R titers at baseline [127.6 (35.7-310.8) vs. 110.1 (39.9-226.7) RU/ml] and after Rituximab treatment were similar between the sexes. However, the event rate was significantly higher in females than in males [HR (95%): 2.12 (1.44-3.12), p = 0.0001]. Forty-five of the 62 patients (72.3%) with anti-PLA2R titer below the median progressed to the combined endpoint versus 35 of the 63 (55.6%) with higher titer [HR (95%): 1.97 (1.26-3.07), p < 0.0029]. The highest probability of progressing to the combined endpoint was observed in females with anti-PLA2R antibody titer below the median (86.7%), followed by females with anti-PLA2R antibody titer above the median (83.3%), males with titer below the median (68.1%), and males with titer above the median (44.4%). This trend was statistically significant (p = 0.0023). Similar findings were observed for complete remission (proteinuria <0.3 g/24 h) and after analysis adjustments for baseline serum creatinine. Thus, despite similar immunological features, females were more resilient to renal injury following Rituximab therapy. These findings will hopefully open new avenues to identify the molecular pathways underlying sex-related nephroprotective effects.

Effect and safety profile of belimumab and tacrolimus combination therapy in thirty-three patients with systemic lupus erythematosus

INTRODUCTION/OBJECTIVES

Belimumab combined with mycophenolate mofetil has been proven to be effective for treating systemic lupus erythematosus (SLE) in several randomized controlled trials. Calcineurin inhibitors are also useful in controlling the activity of SLE. However, the safety and effectiveness of belimumab-calcineurin inhibitor combination therapy have not been addressed. Therefore, the current single-center retrospective study aimed to analyze the safety/efficacy profile of belimumab-tacrolimus (B-T) combination therapy in patients with SLE.

METHOD

Patients with SLE administered tacrolimus and belimumab during treatment were included in the study. Samples were analyzed for the drug retention rate, SLE flare rate, infection incidence rate, and glucocorticoid-sparing effect of the B-T combination therapy.

RESULTS

Thirty-three patients with SLE were treated with B-T combination therapy at our institution. Four patients discontinued treatment due to insufficient response or adverse events. The drug retention rate was over 90% at week 52 and approximately 80% at day 1000. Only one patient developed serious infection. The lupus low disease activity state (LLDAS) achievement ratio was 9.1% on the day of initiation and improved to 64.0% at 52 weeks after initiation. SLE flares were observed in three patients (9.1%) in the first 52 weeks after initiation, and in five patients (15.2%) throughout the study period. A glucocorticoid-reducing effect was also observed in patients treated with B-T combination therapy.

CONCLUSIONS

In most patients with SLE, B-T combination therapy is well tolerated with a good efficacy profile and glucocorticoid-reducing effect. Thus, B-T combination therapy represents a feasible option for patients with refractory lupus. Key Points • The safety and effectiveness of belimumab-calcineurin inhibitor combination therapy have not been addressed. • The drug retention rate of belimumab-tacrolimus combination therapy was over 90% at week 52 and around 80% on day 1000 • Almost none of the patients suffered from severe infection after the initiation of belimumab-tacrolimus combination therapy. • Belimumab-tacrolimus combination therapy is efficacious in suppressing lupus activity and achieving LLDAS.

Case Report: Successful treatment of late-onset immune checkpoint inhibitor-associated membranous nephropathy in a patient with advanced renal cell carcinoma

Background

Diagnosing immune checkpoint inhibitor (ICI)-associated nephritis can be challenging since it is a rare complication of therapy, associated with a spectrum of immune-mediated pathologies, and can present months after ICI therapy discontinuation (i.e., late-onset). ICIs are increasingly administered in combination with other cancer therapies with associated nephrotoxicity, further obfuscating the diagnosis of ICI-associated nephritis. In this report, we describe the first suspected case of late-onset ICI-associated membranous nephropathy (MN) in a patient with metastatic clear cell renal cell carcinoma (RCC) who had discontinued ICI therapy 6 months prior to presentation. Prompt recognition of the suspected late-onset immune-related adverse event (irAE) resulted in the successful treatment of MN and continuation of RCC therapy.

Case presentation

A 57-year-old man with metastatic clear cell RCC was responsive to third-line RCC therapy with lenvatinib (oral TKI) and everolimus (oral mTOR inhibitor) when he presented with nephrotic range proteinuria and acute kidney injury (AKI). His kidney biopsy revealed probable secondary MN with subendothelial and mesangial immune complex deposits and negative staining for both phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A). While a diagnosis of paraneoplastic MN could not be excluded, the patient was responding to cancer therapy and had tumor regression. However, 6 months prior to presentation, the patient had received pembrolizumab, an ICI, with his first-line RCC treatment. Due to concern that the patient may be presenting with late-onset ICI-associated MN, he was effectively treated with rituximab, which allowed for his continued RCC therapy.

Conclusion

This report highlights the first case of suspected late-onset ICI-associated MN and the increasing complexity of recognizing renal irAEs. With the growing indications for the use of ICIs in combination with other cancer therapies, recognizing the various presentations of ICI-immune nephritis can help guide patient management and treatment.

Pathogenic Role of MicroRNA Dysregulation in Podocytopathies

MicroRNAs (miRNAs) participate in the regulation of various important biological processes by regulating the expression of various genes at the post-transcriptional level. Podocytopathies are a series of renal diseases in which direct or indirect damage of podocytes results in proteinuria or nephrotic syndrome. Despite decades of research, the exact pathogenesis of podocytopathies remains incompletely understood and effective therapies are still lacking. An increasing body of evidence has revealed a critical role of miRNAs dysregulation in the onset and progression of podocytopathies. Moreover, several lines of research aimed at improving common podocytopathies diagnostic tools and avoiding invasive kidney biopsies have also identified circulating and urine miRNAs as possible diagnostic and prognostic biomarkers for podocytopathies. The present review mainly aims to provide an updated overview of the recent achievements in research on the potential applicability of miRNAs involved in renal disorders related to podocyte dysfunction by laying particular emphasis on focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous nephropathy (MN), diabetic kidney disease (DKD) and IgA nephropathy (IgAN). Further investigation into these dysregulated miRNAs will not only generate novel insights into the mechanisms of podocytopathies, but also might yield novel strategies for the diagnosis and therapy of this disease.

Steroids as treatment for glomerulonephritis: time for a rethink

Glucocorticoids have been a cornerstone of treatment for inflammatory and autoimmune kidney diseases for almost 70 years, yet it is fair to say, we still do not know how ‘best’ to use them. Significant adverse events are associated with their continued use, which contribute to premature patient mortality. Steroid avoidance or minimization is possible and has been tested in various glomerular diseases, as a result of novel agents or innovative regimens using established therapeutics. It is now time to seriously address our use of steroids and educate physicians on better ways of managing inflammatory kidney diseases.

Comprehensively characterizing cellular changes and the expression of THSD7A and PLA2R1 under multiple in vitro models of podocyte injury

The unique morphology and gene expression of podocytes are critical for kidney function, and their abnormalities lead to nephropathies such as diabetic nephropathy and membranous nephropathy. Podocytes cultured in vitro are valuable tools to dissect the molecular mechanism of podocyte injury relative to nephropathy, however, these models have never been comprehensively compared. Here, we comprehensively compared the morphology, cytoskeleton, cell adhesion, cell spreading, cell migration, and lipid metabolism under five commonly used in vitro models including lipopolysaccharide (LPS), puromycin aminonucleoside (PAN), doxorubicin (Dox), high glucose, and glucose deprivation. Our results indicate that all stimulations significantly downregulate the expression of synaptopodin both in human and mouse podocytes. All stimulations affect podocyte morphology but show different intensity and phenotypes. In general, the five stimulations reduce cell adhesion, cell spreading, and cell migration, but the effect in human and mouse podocytes is slightly different. Human podocytes show high expression of genes enriched in the pentose phosphate pathway. Dox and PAN treatment show a strong effect on gene expression in lipid metabolism, while the other three stimulations show minimal effect. The expression of phospholipase A2 receptor (PLA2R1) and type-1 domain-containing protein 7 A (THSD7A) show opposite trends in given cells. Stimulations can dramatically affect the expression of PLA2R1 and THSD7A. Inhibition of super-enhancers reduces PLA2R1 and THSD7A expression, but ERK inhibition enhances their expression. Our results demonstrate distinctive responses in five commonly used in vitro podocyte injury models and the dynamic expression of PLA2R1 and THSD7A, which supply novel information to select suitable podocyte injury models.

Advances in the Management of Primary Membranous Nephropathy and Rituximab-Refractory Membranous Nephropathy

Primary membranous nephropathy (pMN) is an auto-immune disease characterized by auto-antibodies targeting podocyte antigens resulting in activation of complement and damage to the glomerular basement membrane. pMN is the most common cause of nephrotic syndrome in adults without diabetes. Despite a very heterogeneous course of the disease, the treatment of pMN has for many years been based on uniform management of all patients regardless of the severity of the disease. The identification of prognostic markers has radically changed the vision of pMN and allowed KDIGO guidelines to evolve in 2021 towards a more personalized management based on the assessment of the risk of progressive loss of kidney function. The recognition of pMN as an antibody-mediated autoimmune disease has rationalized the use immunosuppressive drugs such as rituximab. Rituximab is now a first line immunosuppressive therapy for patients with pMN with proven safety and efficacy achieving remission in 60-80% of patients. For the remaining 20-40% of patients, several mechanisms may explain rituximab resistance: (i) decreased rituximab bioavailability; (ii) immunization against rituximab; and (iii) chronic glomerular damage. The treatment of patients with rituximab-refractory pMN remains controversial and challenging. In this review, we provide an overview of recent advances in the management of pMN (according to the KDIGO 2021 guidelines), in the understanding of the pathophysiology of rituximab resistance, and in the management of rituximab-refractory pMN. We propose a treatment decision aid based on immunomonitoring to identify failures related to underdosing or immunization against rituximab to overcome treatment resistance.

The Role of Anti-PLA2R and Anti-THSD7A Antibodies in the Pathogenesis and Diagnostics of Primary Membranous Nephropathy: A Review of Current Knowledge for Clinical Practice

Primary membranous nephropathy (PMN) is considered a major cause of nephrotic syndrome. The discovery of circulating autoantibodies directed against glomerular podocytes helped to classify them as autoimmune diseases. Over the past years, there has been an increasing significance of anti-Phospholipase A2 Receptor (anti-PLA₂R), which has been detected in 70–80% of PMN cases, and relevance of anti-Thrombospondin type I domain-containing 7A (anti-THSD7A) even though they are present in 2–5% of patients. The results of clinical and experimental studies indicate that these antibodies are pathogenic. It radically changed the diagnostic and therapeutic approach. Measurement of antibody titers in the serum seems to be a valuable tool for identifying PMN and for the assessment of disease activity. By monitoring pathogenic antibodies levels rather than proteinuria or reduced glomerular filtration rate (GFR) as an indicator of glomerular disease, physicians would easier divide patients into those with active and inactive PMN disease and decide about their therapy. The aim of this review is to evaluate scientific evidence about the role of autoantibodies, namely anti-PLA₂R and anti-THSD7A, as PMN biomarkers. The present manuscript focuses on PMN pathogenesis and key data of diagnosis, monitoring of the disease, and treatment strategies that are currently being used in clinical practice.

Revisiting immunological and clinical aspects of membranous nephropathy

Idiopathic or primary membranous nephropathy (IMN) is one of the most frequent causes of nephrotic syndrome in adults and the elderly. It is characterized by a thickening of the wall of the glomerular capillaries due to the presence of immune complex deposits. 85% of membranous nephropathy cases are classified as primary or idiopathic (IMN). The rest are of secondary origin (SMN), caused by autoimmune conditions or malignant tumors as lung cancer, colon and melanomas. It is an organ-specific autoimmune disease in which the complement system plays an important role with the formation of the membrane attack complex (MAC; C5b-9), which produces an alteration of the podocyte structure. The antigen responsible for 70-80% of IMN is a podocyte protein called M-type phospholipase A2 receptor (PLA2R). More recently, another podocyte antigen has been identified, the "Thrombospondin type-1 domain-containing 7A" (THSD7A), which is responsible for 10% of the cases of negative IMN for anti- PLA2R.

Detecting Autoantibodies by Multiparametric Assays: Impact on Prevention, Diagnosis, Monitoring, and Personalized Therapy in Autoimmune Diseases

BACKGROUND

The introduction of multiparametric autoantibody tests has been proposed to improve the accuracy of the immunological diagnosis of autoimmune diseases (AID) and to accelerate time for completing the diagnostic process. Multiplex tests are capable of detecting many autoantibodies in a single run whereas a traditional immunoassay uses a single antigen to detect only a single specificity of autoantibodies. The reasons why multiplex tests could replace conventional immunoassays lie in the evidence that they allow for more efficient handling of large numbers of samples by the laboratory, while ensuring greater diagnostic sensitivity in AID screening.

CONTENT

This review aims to highlight the important role that multiparametric tests could assume when designed for defined profiles they are used not only for diagnostic purposes but also to predict the onset of AID to identify clinical phenotypes and to define prognosis. Furthermore, differences in the antibody profile could identify which subjects will be responsive or not to a specific pharmacological treatment.

SUMMARY

The use of autoantibody profiles, when specifically requested and performed with clinically validated technologies, can represent a significant step toward personalized medicine in autoimmunology.

Retrospective analysis of Tripterygium wilfordii polyglycoside combined with angiotensin receptor blockers for the treatment of primary membranous nephropathy with sub-nephrotic proteinuria

INTRODUCTION

Primary membranous nephropathy (PMN) is one common cause of end-stage kidney disease. There is no optimal treatment for PMN patients with sub-nephrotic proteinuria currently. Tripterygium wilfordii polyglycoside (TWG) is a widely used traditional medicine in China and has been used to treat nephropathy for decades.

OBJECTIVE

To investigate the effect of TWG combined with angiotensin receptor blocker (ARB) on the treatment of PMN with sub-nephrotic proteinuria.

METHODS

Biopsy-proven sub-nephrotic PMN patients with normal kidney function and treated with TWG combined with ARB or ARB alone were retrospectively analyzed. The primary outcome was remission rate (complete or partial remission), and the secondary outcomes included proteinuria, serum albumin levels, estimated glomerular filtration rate (eGFR), relapse rate, and adverse events.

RESULTS

The clinical trial included 55 patients. The overall remission rates for the TWG + ARB and ARB groups after 9 months of treatment were 74.3% and 35%, respectively (p = 0.004). Moreover, the complete remission (CR) rate for the TWG + ARB and ARB groups in the 9th month were 45.7% and 15%, respectively (p = 0.044). Treatment with TWG + ARB was the independent predictor of complete remission of proteinuria (p = 0.048). Besides, the remission rate was higher in the TWG + ARB group than in the ARB group among patients who were positive for anti-phospholipase A2 receptor (PLA2R) antibodies (65.4% vs. 21.4%, p = 0.02).

CONCLUSIONS

These data demonstrate that TWG may be a promising treatment for PMN patients with sub-nephrotic proteinuria, whether anti-PLA2R antibody is positive or negative.

Effect of Mahuang Fuzi and Shenzhuo Decoction on Idiopathic Membranous Nephropathy: A Multicenter, Nonrandomized, Single-Arm Clinical Trial

Objective: To explore the clinical effect of Mahuang Fuzi and Shenzhuo Decoction on idiopathic membranous nephropathy.

Methods: This study is a multicenter, nonrandomized, single-arm clinical trial carried out as per the objective performance criteria, with the target being set at 35.0%. 184 cases of patients suffering from idiopathic membranous nephropathy with Shaoyin Taiyin syndrome were collected. These patients were treated with Mahuang Fuzi and Shenzhuo Decoction with a follow-up period of 3 years. The 24-hour urine protein and blood albumin were observed, and the remission rates of the patients were compared with the target.

Results: The mean follow-up time was 18 (12.5, 30) months, and the remission rate was 61.4%, which is a statistically significant difference from the target group of 35%. The remission rates for patients who had and had not used immunosuppressive therapy were 59.6 and 65.5%, respectively, but the difference was not statistically significant (p = 0.254). However, the albumin before the treatment and the course of treatment of the patients was significantly correlated with the disease remission (p < 0.05). However, the albumin before the treatment and the course of treatment of the patients was significantly correlated with the disease remission (p < 0.05). There were no significant changes in renal function before and after treatment, and no severe adverse events occurred during treatment.

Conclusion: Mahuang Fuzi and Shenzhuo Decoction have significant effects on idiopathic membranous nephropathy, and has the same effect on patients with membranous nephropathy who are newly treated as well as those who have been treated with immunosuppressive therapy without remission. In addition, the efficacy of this regimen is related to the albumin and the duration of the therapy, but not to 24-hour urine protein or other factors.