Treatment of idiopathic membranous nephropathy

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.

Defining the threshold: triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio's non-linear impact on tubular atrophy in primary membranous nephropathy

Background

Hyperlipidemia is common in primary membranous nephropathy (PMN) patients, and tubular atrophy (TA) is an unfavorable prognostic factor. However, the correlation between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and TA is controversial. Therefore, our study aimed to investigate the association between the TG/HDL-C ratio and TA in PMN patients.

Methods

We conducted a cross-sectional study and collected data from 363 PMN patients at Shenzhen Second People's Hospital from January 2008 to April 2023. The primary objective was to evaluate the independent correlation between the TG/HDL-C ratio and TA using binary logistic regression model. We used a generalized additive model along with smooth curve fitting and multiple sensitivity analyses to explore the relationship between these variables. Additionally, subgroup analyses were conducted to delve deeper into the results.

Results

Of the 363 PMN patients, 75 had TA (20.66%). The study population had a mean age of 46.598 ± 14.462 years, with 217 (59.78%) being male. After adjusting for sex, age, BMI, hypertension, history of diabetes, smoking, alcohol consumption, UPRO, eGFR, HB, FPG, and ALB, we found that the TG/HDL-C ratio was an independent risk factor for TA in PMN patients (OR=1.29, 95% CI: 1.04, 1.61, P=0.0213). A non-linear correlation was observed between the TG/HDL-C ratio and TA, with an inflection point at 4.25. The odds ratios (OR) on the left and right sides of this inflection point were 1.56 (95% CI: 1.17, 2.07) and 0.25 (95% CI: 0.04, 1.54), respectively. Sensitivity analysis confirmed these results. Subgroup analysis showed a consistent association between the TG/HDL-C ratio and TA, implying that factors such as gender, BMI, age, UPRO, ALB, hypertension and severe nephrotic syndrome had negligible effects on the link between the TG/HDL-C ratio and TA.

Conclusion

Our study demonstrates a non-linear positive correlation between the TG/HDL-C ratio and the risk of TA in PMN patients, independent of other factors. Specifically, the association is more pronounced when the ratio falls below 4.25. Based on our findings, it would be advisable to decrease the TG/HDL-C ratio below the inflection point in PMN patients as part of treatment strategies.

Anti-phospholipase A2 receptor positive membranous nephropathy: investigating the link between electron microscopy stages and clinical outcome

This retrospective, observational study sought to examine the relationship between Ehrenreich-Churg electron microscopy (EM) stages and long-term outcomes in anti-PLA2R membranous nephropathy (MN). Seventy-one patients with anti-PLA2R MN (median titer 185.7RU/mL) were followed for a median of 46 months, with end-stage kidney disease (ESKD) as the primary endpoint, and response to treatment as a secondary endpoint. Patients were grouped into stages I-II (41 patients) and stages III-IV (30 patients) for analytical purposes. Notably, the III-IV group demonstrated a lower eGFR, lower anti-PLA2R titer, but a higher chronicity score. Kaplan-Meier analysis showed shorter mean kidney survival time in stages III-IV compared to I-II (p 0.03). However, multivariate analysis using Cox regression indicated that Ehrenreich-Churg stages did not significantly influence kidney survival, but lower eGFR at diagnosis and higher histopathological chronicity score did. Remission was achieved by 64% of patients and no relationship between Ehrenreich-Churg stages and treatment response was found. The only identified risk factor for not achieving remission was the severity of hyposerinemia at diagnosis. In conclusion, while EM stages III-IV are associated with more chronic lesions and stages I-II with more active immunologic disease, the histological chronicity score seems to be a stronger predictor of long-term outcomes.

Correlation Analysis between Intrarenal Small Artery Intimal Thickening and Clinicopathological Features and Prognosis in Primary Membranous Nephropathy Patients

BACKGROUND

Primary membranous nephropathy (PMN) is the most common pathological type of nephrotic syndrome in adults. Intrarenal small artery intimal thickening can be observed in most renal biopsies. The purpose of this study was to investigate the association between intrarenal small artery intimal thickening and clinicopathological features and prognosis in PMN patients.

METHODS

Data were continuously collected from patients who were diagnosed with PMN in Shenzhen Second People's Hospital (The First Affiliated Hospital of Shenzhen University) from 2008 to 2021 for a retrospective cohort study. Regression analysis and survival analysis were used to analyze the relationship between intrarenal small artery intimal thickening and renal prognosis in PMN patients.

RESULTS

300 PMN patients were enrolled in this study, including 165 patients (55%) with intrarenal small artery intimal thickening. Patients with intimal thickening were older, with higher BMI, systolic blood pressure and diastolic blood pressure, serum uric acid, a higher proportion of hypertension, acute kidney injury, nephrotic syndrome, more urine protein, and lower eGFR. Multivariate Cox regression analysis showed that after adjusting for age, gender, hypertension, BMI, urine protein, eGFR, and the use of ACEI/ARB and hormone immunosuppressants, intimal thickening was a risk factor for renal prognosis in PMN patients (HR = 3.68, 95% CI 1.36-9.96, p < 0.05). Kaplan-Meier survival curve analysis showed that the incidence of reaching the renal composite outcome was higher in the intimal thickening group (p < 0.05).

CONCLUSION

The prognosis of PMN patients with intrarenal small artery intimal thickening is worse, so early intervention is very important for these patients.

Non-Full House Membranous Lupus Nephritis Represents a Clinically Distinct Subset

Key Points

Non-full house (NFH) membranous lupus nephritis (MLN) is a minor subset of all MLN cases. Patients with NFH MLN tend to be older when diagnosed with systemic lupus erythematosus, undergo first renal biopsy at an older age, and have fewer extrarenal systemic manifestations. Lower load of C3 glomerular deposits seen in NFH MLN biopsies suggests attenuation of complement-mediated injury, which may have wider systemic implications.

Background

Renal involvement in systemic lupus erythematosus (SLE) is a key predictor of morbidity and mortality. Immunofluorescence (IF) staining of glomeruli is typically positive for IgG, IgA, IgM, C3, and C1q—the full house (FH) pattern. However, a subset of patients with membranous lupus nephritis (MLN) have a Non-FH (NFH) IF pattern more typical of idiopathic membranous nephropathy.

Methods

From a multi-institutional cohort of 113 MLN cases, we identified 29 NFH MLN biopsies. NFH MLN was defined by IF criteria: ≥1+ glomerular capillary loop IgG staining and<1+ IgA, IgM, and C1q. FH MLN was defined as ≥1+ staining for all five antibodies. Intermediate (Int) cases did not meet criteria for FH or NFH. We compared the pathological and clinical characteristics and outcomes among patients with FH, NFH, and Int IF patterns on kidney biopsy.

Results

NFH MLN represents a subset of MLN biopsies (13.4%). Compared with patients with FH MLN, patients with NFH MLN were older at SLE diagnosis (29 versus 22.5 years), had a longer time to initial kidney biopsy (8 versus 3.16 years), and had fewer SLE manifestations (2.5 versus 3.36 involved systems). NFH MLN biopsies showed lower C3 IF intensity (1.16+ versus 2.38+). Int biopsies had findings intermediate between those of NFH and FH groups.

Conclusions

NFH IF pattern defines a small subset of MLN biopsies and appears to be associated with milder clinical manifestations and slower disease progression. Less robust C3 deposition in NFH MLN may suggest a pathophysiology distinct from that of FH MLN.

Recoverability of Diabetic Nephropathy of Donor Kidney After Kidney Transplantation

Some kidney donors have diabetes, and little of their natural course of diabetic nephropathy (DN) is known. The aim of this study was to analyze the changes in pathologic lesions in the diabetic donor kidney after KT by performing protocol biopsy two weeks and one year after KT. This retrospective study included 103 patients who underwent KT, with kidneys from donors with a history of diabetes mellitus (DM). Among them, data of 34 patients who underwent biopsy two weeks and one year after KT were reviewed. Biopsy specimens were reviewed using light microscopy and electron microscopy. Glomerular basement membrane (GBM) thickness at 2 weeks and 1 year was compared. Biopsy showed that DN occurred in 29 of the 34 patients. Only trivial histological changes were observed in 22 patients (64.7%), including 5 patients who did not show DN. At one year after transplantation, there was no change in the DN histologic class in 26 patients (76.5%), and there was no statistically significant difference in the change in GBM thickness. This pattern was observed regardless of the recipient’s DM or glycemic control. With this understanding, clinicians can use kidneys from DM donors with more comfort, thereby reducing the kidney discard rate.

A novel FOXP3 mutation in a Chinese child with IPEX-associated membranous nephropathy

BACKGROUND

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic immunodeficiency disease caused by forkhead box protein3 (FOXP3) mutation. The kidney is commonly involved in IPEX syndrome, but there were few studies focusing on renal involvement.

METHODS

Whole-exome sequencing was used to identify the novel FOXP3 mutation. We collected clinical manifestations, kidney pathology, and gene function of the proband. All the previously published studies with IPEX-associated renal involvement were reviewed.

RESULTS

We report a late-onset Chinese child with IPEX-associated membranous nephropathy (MN). Type 1 diabetes mellitus and nephrotic-range proteinuria are the main clinical manifestations. Whole-exome sequencing shows a novel c.766A > G mutation in the FOXP3 gene. The literature review indicates that renal manifestations include proteinuria, microscopic hematuria, and renal insufficiency. MN is the most common pathological type in children with IPEX, followed by tubulointerstitial nephritis, interstitial nephritis, minimal change nephrotic syndrome, and membranoproliferative glomerulonephritis.

CONCLUSION

In summary, we report a novel FOXP3 mutation (c.766A > G) with MN stage II in IPEX. In a literature review, MN is the most common pathological type in children with IPEX and proteinuria is the most prevalent clinical feature. IPEX should be considered in the differential diagnosis of MN patients with related endocrine diseases and immune disorders.

Therapies for Membranous Nephropathy: A Tale From the Old and New Millennia

Primary Membranous Nephropathy (PMN) is the most frequent cause of nephrotic syndrome in adults. If untreated, PMN can lead to end-stage renal disease; moreover, affected patients are at increased risk of complications typical of nephrotic syndrome such as fluid overload, deep vein thrombosis and infection. The association of PMN with HLA-DQA1 and the identification in around 70% of cases of circulating autoantibodies, mainly directed towards the phospholipase A2 receptor, supports the autoimmune nature of the disease. In patients not achieving spontaneous remission or in the ones with deteriorating kidney function and severe nephrotic syndrome, immunosuppression is required to increase the chances of achieving remission. The aim of this review is to discuss the evidence base for the different immunosuppressive regimens used for PMN in studies published so far; the manuscript also includes a section where the authors propose, based upon current evidence, their recommendations regarding immunosuppression in the disease, while highlighting the still significant knowledge gaps and uncertainties.

Immunosuppressive treatment for primary membranous nephropathy in adults with nephrotic syndrome

BACKGROUND

Primary membranous nephropathy (PMN) is a common cause of nephrotic syndrome in adults. Without treatment, approximately 30% of patients will experience spontaneous remission and one third will have persistent proteinuria. Approximately one-third of patients progress toward end-stage kidney disease (ESKD) within 10 years. Immunosuppressive treatment aims to protect kidney function and is recommended for patients who do not show improvement of proteinuria by supportive therapy, and for patients with severe nephrotic syndrome at presentation due to the high risk of developing ESKD. The efficacy and safety of different immunosuppressive regimens are unclear. This is an update of a Cochrane review, first published in 2004 and updated in 2013.

OBJECTIVES

The aim was to evaluate the safety and efficacy of different immunosuppressive treatments for adult patients with PMN and nephrotic syndrome.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 1 April 2021 with support from the Cochrane Kidney and Transplant Information Specialist using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) investigating effects of immunosuppression in adults with PMN and nephrotic syndrome were included.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, quality assessment, and data synthesis were performed using Cochrane-recommended methods. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Sixty-five studies (3807 patients) were included. Most studies exhibited a high risk of bias for the domains, blinding of study personnel, participants and outcome assessors, and most studies were judged unclear for randomisation sequence generation and allocation concealment. Immunosuppressive treatment versus placebo/no treatment/non-immunosuppressive treatment In moderate certainty evidence, immunosuppressive treatment probably makes little or no difference to death, probably reduces the overall risk of ESKD (16 studies, 944 participants: RR 0.59, 95% CI 0.35 to 0.99; I² = 22%), probably increases total remission (complete and partial) (6 studies, 879 participants: RR 1.44, 95% CI 1.05 to 1.97; I² = 73%) and complete remission (16 studies, 879 participants: RR 1.70, 95% CI 1.05 to 2.75; I² = 43%), and probably decreases the number with doubling of serum creatinine (SCr) (9 studies, 447 participants: RR 0.46, 95% CI 0.26 to 0.80; I² = 21%). However, immunosuppressive treatment may increase the number of patients relapsing after complete or partial remission (3 studies, 148 participants): RR 1.73, 95% CI 1.05 to 2.86; I² = 0%) and may lead to a greater number experiencing temporary or permanent discontinuation/hospitalisation due to adverse events (18 studies, 927 participants: RR 5.33, 95% CI 2.19 to 12.98; I² = 0%). Immunosuppressive treatment has uncertain effects on infection and malignancy. Oral alkylating agents with or without steroids versus placebo/no treatment/steroids Oral alkylating agents with or without steroids had uncertain effects on death but may reduce the overall risk of ESKD (9 studies, 537 participants: RR 0.42, 95% CI 0.24 to 0.74; I² = 0%; low certainty evidence). Total (9 studies, 468 participants: RR 1.37, 95% CI 1.04 to 1.82; I² = 70%) and complete remission (8 studies, 432 participants: RR 2.12, 95% CI 1.33 to 3.38; I² = 37%) may increase, but had uncertain effects on the number of patients relapsing, and decreasing the number with doubling of SCr. Alkylating agents may be associated with a higher rate of adverse events leading to discontinuation or hospitalisation (8 studies 439 participants: RR 6.82, 95% CI 2.24 to 20.71; I² = 0%). Oral alkylating agents with or without steroids had uncertain effects on infection and malignancy. Calcineurin inhibitors (CNI) with or without steroids versus placebo/no treatment/supportive therapy/steroids We are uncertain whether CNI with or without steroids increased or decreased the risk of death or ESKD, increased or decreased total or complete remission, or reduced relapse after complete or partial remission (low to very low certainty evidence). CNI also had uncertain effects on decreasing the number with a doubling of SCr, temporary or permanent discontinuation or hospitalisation due to adverse events, infection, or malignancy. Calcineurin inhibitors (CNI) with or without steroids versus alkylating agents with or without steroids We are uncertain whether CNI with or without steroids increases or decreases the risk of death or ESKD. CNI with or without steroids may make little or no difference to total remission (10 studies, 538 participants: RR 1.01, 95% CI 0.89 to 1.15; I² = 53%; moderate certainty evidence) or complete remission (10 studies, 538 participants: RR 1.15, 95% CI 0.84 to 1.56; I² = 56%; low certainty evidence). CNI with or without steroids may increase relapse after complete or partial remission. CNI with or without steroids had uncertain effects on SCr increase, adverse events, infection, and malignancy. Other immunosuppressive treatments Other interventions included azathioprine, mizoribine, adrenocorticotropic hormone, traditional Chinese medicines, and monoclonal antibodies such as rituximab. There were insufficient data to draw conclusions on these treatments.

AUTHORS' CONCLUSIONS

This updated review strengthened the evidence that immunosuppressive therapy is probably superior to non-immunosuppressive therapy in inducing remission and reducing the number of patients that progress to ESKD. However, these benefits need to be balanced against the side effects of immunosuppressive drugs. The number of included studies with high-quality design was relatively small and most studies did not have adequate follow-up. Clinicians should inform their patients of the lack of high-quality evidence. An alkylating agent (cyclophosphamide or chlorambucil) combined with a corticosteroid regimen had short- and long-term benefits, but this was associated with a higher rate of adverse events. CNI (tacrolimus and cyclosporin) showed equivalency with alkylating agents however, the certainty of this evidence remains low. Novel immunosuppressive treatments with the biologic rituximab or use of adrenocorticotropic hormone require further investigation and validation in large and high-quality RCTs.

Membranous nephropathy in a patient with pulmonary tuberculosis infection and lung adenocarcinoma: a case report

We report a case of membranous nephropathy (MN) in a patient with tuberculosis infection and lung adenocarcinoma. A 50-year-old Filipino woman underwent a renal biopsy for the evaluation of proteinuria and hematuria. Immunofluorescence analysis revealed positive staining of IgG in the glomerular basement membrane and mesangial matrices, while electron microscopy demonstrated the presence of sub-epithelial deposits, suggesting MN. To screen for secondary causes of MN, we conducted a computed tomography (CT) scan of the chest and abdomen, which revealed a ground-glass opacity in the middle lobe of the right lung and an enlarged paraaortic lymph node. A T-SPOT test was positive, suggesting the possibility of a latent tuberculosis infection, as she was asymptomatic. A follow-up chest CT scan showed persistent presence of the ground-glass opacities, suggesting a non-infectious cause. Video-assisted thoracoscopic resection of the middle right lobe and partial resection of the lower right lobe were performed because the possibility of lung cancer could not be excluded. Notably, pathological analysis of the lung revealed adenocarcinoma in the middle lobe and epithelioid granuloma in the lower lobe, suggesting an active tuberculosis infection. One month after surgery, anti-tuberculosis treatment was initiated. Thereafter, her proteinuria, which had increased to 6 g/gCre preoperatively, began to decrease. Five months after surgery, the patient achieved complete remission. The speed of remission suggests that tuberculosis likely played a primary role in the etiology of MN. Our case underscores the importance of screening tests for infections and malignancies in patients with MN, even if suggestive symptoms are absent.

Outcomes of primary membranous nephropathy based on serum anti-phospholipase A2 receptor antibodies and glomerular phospholipase A2 receptor antigen status: a retrospective cohort study

Introduction

Primary membranous nephropathy (PMN) is associated with the anti-phospholipase A2 receptor (anti-PLA2R) antibody in 70% of cases. Some anti-PLA2R-negative patients have the PLA2R antigen in renal tissue. This study examined the prognosis of patients with PMN according to their serum anti-PLA2R antibody (SAb) and glomerular PLA2R antigen (GAg) status.

Methods

Patients diagnosed with PMN were included retrospectively. Patients were grouped according to their PLA2R status into the SAb−/GAg−, SAb−/GAg+, and SAb+/GAg + groups. Baseline data, renal biopsy results, treatment, and clinical data were compared among the groups. Cox univariable and multivariable analyses examined the factors related to complete remission (CR).

Results

A total of 114 patients were enrolled; 10 (9%) in the SAb−/GAg−, 23 (20%) in the SAb−/GAg+, and 81 (71%) in the SAb+/GAg+ groups. Cumulative CR rate showed a significant difference between the SAb−/GAg − and SAb+/GAg+ groups (log-rank p = 0.003). The multivariable Cox proportional hazard analysis showed that age (HR = 0.968; 95%CI = 0.946–0.990; p = 0.005), SAb+/GAg+ versus SAb−/GAg− (HR = 0.387; 95%CI = 0.190–0.788; p = 0.009), SAb−/GAg+ versus SAb−/GAg− (HR = 0.398; 95%CI = 0.169, 0.939; p = 0.035), total renal chronicity score ≥2 (HR = 0.461, 95%CI: 0.277–0.766, p = 0.003), and IgA deposition (HR = 2.596; 95%CI = 1.227–5.492; p = 0.013) were all independently related (p < 0.05) to CR.

Conclusions

The SAb and GAg status was an indicator of PMN prognosis. The patients with SAb−/GAg − had an increased likelihood of achieving CR than those with SAb−/GAg+ and SAb+/GAg+.

Electron-Dense Deposition Patterns and the Outcomes of Nephrotic Idiopathic Membranous Nephropathy Treated with Tacrolimus in Chinese Adults

Background

Tacrolimus may be effective in the short-term treatment of idiopathic membranous nephropathy (IMN). However, it is not clear whether an electron microscopic classification of the homogeneous and heterogeneous types of nephrotic IMN is related to the efficacy of tacrolimus in patients with IMN. This study aimed to explore this question and to provide evidence for individualized patient treatment.

Material/Methods

This 6-month retrospective study included 61 Chinese patients previously diagnosed with IMN. Patients received treatment was tacrolimus plus glucocorticoid. The patients were divided into a homogeneous group and a heterogeneous group based on the evaluation of electron-dense deposits. The initial clinicopathologic factors in the 2 groups were analyzed, and the difference in efficacy of tacrolimus in the 2 groups was assessed. The factors predicting remission were also studied.

Results

No significant alteration in the initial clinicopathologic status was found between the 2 groups, except for proteinuria, serum albumin levels, systolic blood pressure, and renal biopsy results (stages I/II/III/IV). After 3 months of treatment, the difference in remission was not significant between the 2 groups. However, after 6 months of treatment, a significant difference in remission rates was observed between the 2 groups. The binary logistic model showed that the homogeneous nephrotic IMN was independently associated with total remission (partial plus complete remission), and was also related to complete remission.

Conclusions

The results of our study revealed that the homogeneous type of nephrotic IMN had a higher short-term remission rate and a predictive value for partial or complete remission, and it might be a meaningful marker of the short-term response to tacrolimus.

Clinical significance of glomerular C3 deposition in primary membranous nephropathy

BACKGROUND

We aimed to investigate the effects of glomerular C3 deposition on clinical, histopathological features, and outcomes of patients with primary membranous nephropathy (MN).

METHODS

A total of 261 patients with biopsy-proven primary MN, who were on follow up for at least 6 months, were included in the study. The patients were grouped according to their C3 immunostaining in kidney biopsy samples at the time of diagnosis: Low intensity [LI; (C3 1 +)] and high intensity [HI; (C3 2 + or C3 3 +)]. The primary outcome was the development of kidney failure. Complete (CR) or partial remission (PR) was defined as secondary outcome.

RESULTS

Sixteen patients reached the primary outcome after a median follow-up of 33.8 months. Patients in the high intensity group (119 cases) had lower eGFR and higher proteinuria at admission and last follow-up compared to patients in the low intensity group (142 cases). Also, more patients in the high intensity group reached the primary outcome compared to patients in the low intensity group: twelve patients (10.1%) in the high intensity group and four patients (2.8%) in the low intensity group reached the primary outcome (p = 0.015). Kaplan-Meier analysis demonstrated that patients in the high intensity group had a higher risk for kidney failure (p = 0.02). In multivariate logistic regression analysis, high intensity C3 deposition and initial estimated glomerular filtration rate (eGFR) indepenently predicted primary outcome.

CONCLUSION

Extensive glomerular C3 deposition is a predictor of kidney failure in patients with MN.

A nomogram for the prediction of renal outcomes among patients with idiopathic membranous nephropathy

The early prediction of renal outcomes in patients with idiopathic membranous nephropathy (iMN) remains challenging. The present retrospective study evaluated patients with iMN confirmed by renal biopsy. An optimized Cox regression model and a nomogram were constructed for the early prediction of renal outcomes. A total of 141 patients who met the inclusion criteria were evaluated in the present study. In total 18 (12.8%) patients eventually progressed to the endpoint, 6 of whom developed end-stage renal disease, and one patient died during follow-up. The optimized model demonstrated that 24-h proteinuria [hazard ratio (HR) 1.24; 95% CI, 1.10-1.40; P-value <0.001] and chronic tubulointerstitial injury [referred to as grade 0, grade 1 (HR), 5.12; 95% CI, 1.33-19.75; P-value=0.02] or grade 2 (HR, 6.43; 95% CI, 1.35-30.59; P-value=0.02) were independent risk factors for a poor renal outcome. Patients with an estimated three-year renal survival rate (ETR) less than 0.87 had a high risk of a poor renal outcome. In addition, patients with an ETR of 0.87 to 0.98 more quickly developed a decreased estimated glomerular filtration rate after two years of follow-up. In the present study a nomogram for the early prediction of renal outcomes in patients with iMN was developed. This nonogram suggested that patients with an ETR of 0.87-0.98 should receive greater attention during follow-up.

Podocyte Antigen Staining to Identify Distinct Phenotypes and Outcomes in Membranous Nephropathy: A Retrospective Multicenter Cohort Study

RATIONALE & OBJECTIVE

Membranous nephropathy (MN) is characterized by the deposition of immune complexes along glomerular basement membranes. M-Type phospholipase A₂ receptor (PLA₂R), thrombospondin type 1 domain-containing 7A (THSD7A), exostosin 1 and 2 (EXT1/2), and neural epidermal growth factor-like 1 protein (NELL-1) have been identified as established or potential podocyte antigens in MN. We investigated the association of podocyte antigen staining with MN clinical phenotype and outcomes.

STUDY DESIGN

Multicenter retrospective cohort study.

SETTING & PARTICIPANTS

177 consecutive patients with MN unrelated to lupus erythematosus, identified after screening of 3,875 native kidney biopsies performed in the Belgian UCLouvain Kidney Disease Network from 2000 through 2018.

PREDICTOR

Positive immunostaining for podocyte antigens on archived kidney biopsy samples.

OUTCOMES

Association with different phenotypes (baseline characteristics of patients and pathologic findings on kidney biopsy), time to cancer and to kidney failure.

ANALYTICAL APPROACH

Kaplan-Meier estimates and Cox regression analyses to assess time to cancer and kidney failure.

RESULTS

177 patients were followed up for a median of 4.0 (IQR, 1.3-8.0) years. Diagnosis of PLA₂R-positive (PLA₂R⁺), THSD7A⁺, and double-negative (PLA₂R^-/THSD7A^-) MN was made in 117 (66.1%), 6 (3.4%), and 54 (30.5%) patients, respectively. Progression to kidney failure was similar in all groups. Although the number of patients with THSD7A⁺MN was small, they showed a higher incidence (50%) and increased risk for developing cancer during follow-up (adjusted HR, 5.0 [95% CI, 1.4-17.9]; P=0.01). 8% and 5% of patients with double-negative MN stained positively for EXT1/2 and NELL-1, respectively. Most patients with EXT1/2⁺MN were women, had features of systemic autoimmunity, and showed glomerular C1q deposits.

LIMITATIONS

Retrospective design; small number of patients in the THSD7A group; lack of evaluation of immunoglobulin G subclasses deposition.

CONCLUSIONS

Our real-world data describe the relative prevalence of subgroups of MN and support the hypothesis that a novel classification of MN based on podocyte antigen staining may be clinically relevant.

Validation of phospholipase A2 receptor direct immunofluorescence staining in the diagnosis of primary membranous glomerulonephritis

Distinguishing between primary and secondary subtypes of membranous glomerulonephritis (MGN) is critical for its clinical management. We prospectively compared direct immunofluorescence (DIF) staining for phospholipase A₂ receptor (PLA₂R) on frozen renal biopsy with the presence of detectable serum PLA₂R antibody assessed by enzyme linked immunosorbent assay (ELISA) in the diagnosis of primary MGN. Forty-six patients with biopsy-proven MGN were enrolled from April 2017 to June 2019 with 31/46 (67.4%) being primary and 15/46 (32.6%) being secondary as determined by comprehensive clinical assessment. This is currently deemed to be the gold standard for distinguishing primary from secondary MGN. Amongst the 31 primary MGN patients, 24/31 were positive on PLA₂R DIF staining compared to 18/31 being positive on the PLA₂R ELISA (p=0.03). Amongst the 15 secondary MGN patients, 1/15 was positive on PLA₂R DIF compared to 0/15 on PLA₂R ELISA (p=1.0). In conclusion, the presence of PLA₂R staining on DIF demonstrated superior sensitivity and similar specificity compared to the detection of circulating PLA₂R antibodies by ELISA in the diagnosis of primary MGN in a cohort of 46 patients with biopsy-proven MGN. We suggest that DIF should be considered as part of routine work-up in all newly diagnosed cases of MGN.

Membranous nephropathy associated with profound hypothyroidism

Membranous nephropathy can be primary or secondary. Although common causes of secondary MN are malignancy and lupus, hypothyroidism was rarely reported. Providers should check thyroid function tests in patients with unexplained nephrotic proteinuria.

Clinicopathological features in membranous nephropathy with cancer: A retrospective single-center study and literature review

BACKGROUND

Membranous nephropathy is the most common glomerular disease related to malignancy. However, it is difficult to distinguish between true malignancy-related membranous nephropathy and idiopathic membranous nephropathy coincident with cancer. It has been reported that phospholipase A2 receptor (PLA2R) is the first autoantigen involved in idiopathic membranous nephropathy and thrombospondin type-1 domain-containing 7A (THSD7A) may have a close relationship with malignancy-related membranous nephropathy. Therefore, the aim of this study was to compare the clinicopathological characteristics between membranous nephropathy patients with cancer and idiopathic membranous nephropathy patients without cancer to better detect malignancy-related membranous nephropathy, including glomerular PLA2R and THSD7A depositions and their circulating antibodies, together with glomerular IgG4 deposition.

METHODS

Twelve membranous nephropathy patients with cancer and 257 idiopathic membranous nephropathy patients without cancer were included in this study and had been followed up for more than 1 year. The glomerular expression of PLA2R, THSD7A, and IgG4 was analyzed by immunohistochemistry. Circulating anti-PLA2R and anti-THSD7A antibodies were assessed by enzyme-linked immunosorbent assay and indirect immunofluorescence testing, respectively.

RESULTS

Membranous nephropathy patients with cancer were significantly older and had higher serum creatinine and a lower estimated glomerular filtration rate than idiopathic membranous nephropathy patients (P<0.05). The positive rates of glomerular PLA2R and IgG4 depositions and circulating anti-PLA2R antibodies in membranous nephropathy patients with cancer were significantly lower than those in idiopathic membranous nephropathy patients without cancer (P<0.01).

CONCLUSION

The absence of glomerular PLA2R deposition and negative circulating anti-PLA2R antibodies, along with negative glomerular IgG4 staining, may be useful clues to more accurately screen underlying malignancies in membranous nephropathy patients.

[Membranous nephropathy in a Russian population]

AIM

To analyze the clinical and morphological manifestations of membranous nephropathy (MN) and to evaluate the efficiency of its therapy.

MATERIAL AND METHODS

MN cases in 2009 to 2016 were retrospectively detected with a subsequent analysis of patients with primary MN (PMN). The titer of IgG-autoantibodies to phospholipase A2 receptor (anti-PLA2R Ab) was determined by an indirect immunofluorescence assay. Treatment outcomes, such as the time course of changes in proteinuria, nephrotic syndrome (NS), and the development of complete and partial remissions (CR and PR), were assessed.

RESULTS

MN was detected in 201 cases; the secondary etiology of the disease was established in 24.9%. The prevalence of MN among morphologically confirmed glomerulopathies was 14%; that of PMN was 10.4%. The median period to diagnosis PMN was 8 (5; 19) months. 150 patients with PMN (66.7% were men; age was 50±15 years) were distributed according to the following morphological stages: Stages I (23.9%), II (48.5%), III (26.1%), and IV (1.5%). Elevated anti-PLA2R Ab levels were found in 51.6% of cases; NS in the presence of proteinuria was detected in 85.6% of patients. An estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m2 was seen in 25% of cases. Treatment outcomes were evaluated in 80 cases; the median follow-up period was 19 (8; 40) months. 68% of cases had CR (32%) or PR (36%) with a median follow-up of 26 (13; 44) months. Spontaneous CRs or PRs were observed in 7.5% of the patients. Multivariate analysis showed that the probability of CR or PR increased 3.2-fold in the use of cyclophosphamide and/or cyclosporine and decreased as eGFR dropped.

CONCLUSION

In Russia, PMN is a common type of glomerulopathy, the specific features of which should include the low rates of spontaneous remissions and detection of anti-PLA2R Abs. For renal protection, the majority of patients with PMN require timely diagnosis and treatment; individualization of the choice of treatment and its enhanced efficiency call for further investigations.

Out of Africa: Complete and partial remissions as a combined outcome in patients with idiopathic membranous glomerulonephritis in Cape Town

AIM

Remission outcomes among patients with idiopathic membranous glomerulonephritis is unknown in Africa. We sought to determine remission outcomes in a cohort of South African adult patients with IMGN.

METHODS

This was a retrospective review of patients with biopsy-proven IMGN over a 10 year period. Secondary causes of MN were excluded. Demographic, clinical, biochemical and histological records were retrieved for analysis. The trends in biochemical parameters from baseline were determined. The primary outcome was the attainment of a complete or partial remission (CR / PR) at the last follow-up.

RESULTS

Fifty-six patients met the criteria for inclusion and 43 had subsequent follow-up care with a median duration of follow-up of 23.0 (13.0-48.0) months. Sixteen patients (37.2%) were treated with immunosuppression (corticosteroids and cyclophosphamide) and 81.4% received anti-proteinuric agents. There were no significant differences in demographic and clinical features of patients categorized by immunosuppression (ISP) use. Changes in level of proteinuria and estimated glomerular filtration rate (eGFR) were also not significantly different between the two groups. Eighteen patients (41.9%) reached CR or PR at the last visit. The median times-to-remission of patients according to ISP status were similar at 48.6 and 48.7 months respectively (P = 0.104) while the proportions of patients not reaching CR/PR at 12 and 24 months were 94.6% and 80.8% respectively. Gender and race did not predict remission status (P > 0.05). Predictors of CR/PR at last visit were eGFR [OR 1.01 (95%CI: 1.00 - 1.02); P = 0.041], and systolic BP (OR 0.97 [95%CI: 0.95 - 0.99); P = 0.036].

CONCLUSION

Remission outcomes in this African IMGN cohort are delayed and poor.

Increasing frequency of idiopathic membranous nephropathy in primary glomerular disease: a 10-year renal biopsy study from a single Chinese nephrology centre

AIM

To investigate the changing of idiopathic membranous nephropathy (iMN) in China.

METHODS

This study retrospectively analyzed renal disease spectrum of 6049 patients who underwent renal biopsy at Peking University First Hospital from January 2003 to December 2012. The patients were grouped into two periods at a 5-year interval: 2003-2007 (period 1) and 2008-2012 (period 2).

RESULTS

Among 6049 renal biopsied patients, 3831 (63.3%) patients were diagnosed as primary glomerular disease (PGD). The proportion of nephrotic syndrome (NS) in PGD was significantly higher in period 2 than that in period 1 (1016/2214 [55.0%] vs 682/1617 [42.2%], P = 0.022). The proportion of iMN in PGD increased from 16.8% (217/1617) in period 1 to 29.35% (646/2214) in period 2 in all groups of age (P < 0.001). There was no significant difference of clinical characteristics including age, gender, hypertension, serum cholesterol and proteinuria between the two periods (P > 0.05). However, in young patients with iMN (14-44 years old), the percentage of renal histopathology stage I and stage II of iMN in PGDs was significantly higher in period 2 than that in period 1 (101/1240 [8.15%] vs 210/1340 [15.7%], P < 0.001).

CONCLUSION

Our study suggests that the frequency of iMN in PGD in our referral diagnostic centre has doubled over the past 10 years. The increase of adult iMN is mainly due to the increase of early stages of iMN in young patients.

Management of Membranous Nephropathy in Western Countries

BACKGROUND

Idiopathic membranous nephropathy (IMN) is a common cause of nephrotic syndrome (NS) in adults in Western countries. In 2012, the KDIGO (Kidney Disease: Improving Global Outcomes) working group published guidelines for the management of glomerulonephritis, thus providing a template for the treatment of this condition. While being aware of the impact of the clinicians' acumen and that patients may choose a different therapeutic option due to the risks of specific drugs and also of the evolving guidelines, this review details our approach to the management of patients with IMN in a Western center (Toronto).

SUMMARY

Based on studies published in Europe and North America, we included recent advances in the diagnosis and management of patients with membranous nephropathy similar to our practice population. We highlight the importance of establishing the idiopathic nature of this condition before initiating immunosuppressive therapy, which should include the screening for secondary causes, especially malignancy in the elderly population. The expected outcomes with and without treatment for patients with different risks of progression will be discussed to help guide clinicians in choosing the appropriate course of treatment. The role of conservative therapy as well as of established immunosuppressive treatment, such as the combination of cyclophosphamide and prednisone, and calcineurin inhibitors (CNIs), as well as of newer agents such as rituximab will be reviewed.

KEY MESSAGES

Appropriate assessment is required to exclude secondary conditions causing membranous glomerulonephritis. The role of antibodies to phospholipase A2 receptor (anti-PLA2R) in establishing the primary disease is growing, though more data are required. The increase in therapeutic options supports treatment individualization, taking into account the availability, benefits and risks, as well as patient preference.

FACTS FROM EAST AND WEST

(1) The prevalence of IMN is increasing worldwide, particularly in elderly patients, and has been reported in 20.0-36.8% of adult-onset NS cases. The presence of anti-PLA2R antibodies in serum or PLA2R on renal biopsy is the most predictive feature for the diagnosis of IMN and is used in both the East and West; however, appropriate screening to rule out secondary causes should still be performed. (2) Several observational (nonrandomized) Asian studies indicate a good response to corticosteroids alone in IMN patients, although no randomized controlled trials (RCTs) have been done in Asian membranous patients at high risk of progression. Corticosteroid monotherapy has failed in randomized controlled studies in Western countries and is therefore not recommended. (3) Cyclophosphamide is the most commonly prescribed alkylating agent in Europe and China. Also, chlorambucil is still used in some Western countries, particularly in Europe. In North America, CNIs are the more common first-line treatment. (4) Cyclosporine is predominantly used as monotherapy in North America, although KDIGO and Japanese guidelines still recommend a combination with low-dose corticosteroids. Clinical studies both in Asia and Europe showed no or little effects of monotherapy with mycophenolate mofetil compared to standard therapies. (5) There are encouraging data from nonrandomized Western studies for the use of rituximab and a few small studies using adrenocorticotropic hormone. Clinical trials are ongoing in North America to confirm these observations. These drugs are rarely used in Asia. (6) A Chinese study reported that 36% of IMN patients suffered from venous thromboembolism versus 7.3% in a North American study. Prophylactic anticoagulation therapy is usually added to IMN patients with a low risk of bleeding in both Eastern and Western countries. (7) The Chinese traditional medicine herb triptolide, which might have podocyte-protective properties, is used in China to treat IMN. An open-label, multicenter RCT showed that Shenqi, a mixture of 13 herbs, was superior to corticosteroids plus cyclophosphamide therapy to restore epidermal growth factor receptor in IMN patients, although proteinuria improvement was equal in the two groups. Importantly, Shenqi treatment induced no severe adverse events while standard therapy did.

Clinicopathological characteristics of M-type phospholipase A2 receptor (PLA2R)-related membranous nephropathy in Japanese

BACKGROUND

Recent studies have suggested that assessments of serum antibodies against M-type phospholipase A2 receptor (PLA2R) and the glomerular expression of PLA2R antigen in biopsy specimens are useful for the diagnosis of primary membranous nephropathy (MN). In this study, we assessed both of them and investigated the clinicopathological characteristics of PLA2R-related Japanese MN.

METHODS

We retrospectively enrolled 22 primary and 3 secondary Japanese patients whose serum samples and renal specimens were collected before treatment. According to the findings of serum antibodies and antigen in glomeruli, the primary MN patients were classified into PLA2R-related or -unrelated MN. We compared their clinicopathological findings, including IgG subclass staining, and electron microscopic findings, and evaluated the predictors of proteinuria remission.

RESULTS

In primary MN, 16 patients (73 %) were classified into the PLA2R-related group, and 6 patients into the PLA2R-unrelated group. There was no significant difference in baseline laboratory data and electron microscopic findings, except for eGFR and serum IgG levels. IgG4-dominant deposition was more common in the related group (63 vs. 0 %). The 10 PLA2R-related patients with dominant IgG4 deposition had a lower rate and prolonged time in remission compared with the 6 PLA2R-related patients with non-dominant IgG4 (log-rank, p = 0.032). Furthermore, dominant IgG4 deposition was an unfavorable predictor of remission by multivariable Cox proportional hazard analysis.

CONCLUSIONS

Assessments of both serum PLA2R antibodies and PLA2R antigen in glomeruli were more sensitive for the diagnosis of PLA2R-related MN, and among affected Japanese patients, those with dominant IgG4 deposition had worse clinical outcomes.

Circulating TNF receptors are significant prognostic biomarkers for idiopathic membranous nephropathy

Idiopathic membranous nephropathy (iMN) is a common cause of nephrotic syndrome in adults. A biomarker to accurately indicate the severity of iMN and predict long-term prognosis is insufficient. Here, we evaluated the clinical significance of circulating tumor necrosis factor receptors (cTNFRs) as prognostic biomarkers of iMN with nephrotic syndrome. A total of 113 patients with biopsy-proven iMN and 43 healthy volunteers were enrolled in this study. Ninety patients with iMN had nephrotic range proteinuria. Levels of cTNFRs were measured by using serum samples collected at the time of initial diagnosis. Levels of cTNFRs were higher in the patients with nephrotic syndrome than in those with subnephrotic range proteinuria or in the healthy volunteers (P for trend <0.001). Estimated glomerular filtration rate and proteinuria tended to worsen as the cTNFRs levels increased. Having a cTNFR1 level within the highest tertile was a significant risk factor for renal progression after adjustment, in comparison with the other tertiles (hazard ratio [HR], 3.39; 95% confidence interval [95% CI], 1.48-7.78; P = 0.004). The cTNFR2 level within the highest tertile also significantly increased the risk of renal progression (HR, 3.29; 95% CI, 1.43-7.54; P = 0.005). Renal tubular TNFRs expression was associated with cTNFRs level. However, the cTNFRs levels were not associated with autoantibody against phospholipase A2 receptor reactivity/levels or treatment response. This study demonstrated that cTNFRs levels at the time of initial diagnosis could predict renal progression in patients with iMN.

Lupus-like membranous nephropathy: Is it lupus or not?

BACKGROUND

Membranous glomerulonephritis is typically classified as idiopathic or secondary to systemic lupus erythematosus (SLE), hepatitis B, drugs, toxins, other infections, or malignancy. Not infrequently in some patients without a definite diagnosis of SLE, pathologic features of secondary membranous nephropathy are seen e.g., mesangial and/or subendothelial deposits, tubuloreticular inclusions, and full house immunofluorescence. In these patients, there is uncertainty about the etiology, response to therapy, and prognosis of membranous GN.

METHODS

We retrospectively reviewed the charts of 98 patients with membranous GN at San Francisco General Hospital and John Stroger Hospital of Cook County over a 10-year period. Data were collected and analyzed using SPSS.18.

RESULTS

Thirty-nine (40 %) had idiopathic membranous GN (Group 1), thirty-six (37 %) had lupus membranous GN (Group 2) and twenty-three (23 %) had some pathological features of secondary membranous GN, but no definite etiology of membranous GN (Group 3). At baseline (at time of renal biopsy) and after mean follow-up of 3.5 years, the average serum creatinine (in mg/dL) in Group 1 was (1.6 ± 1.0 versus 1.6 ± 1.7), Group 2 was (1.8 ± 2.5 versus 1.2 ± 0.9) and Group 3 was (1.1 ± 0.4 versus 1.27 ± 0.83), respectively. For the same time points, the average urine protein to creatinine ratio (g/g) in Group 1 was (9.8 ± 7.1 versus 5.7 ± 6.7), Group 2 was (4.2 ± 3.9 versus 1.7 ± 2.2), and Group 3 was (7.4 ± 5.7 versus 3.1 ± 3.8). In addition, during the follow-up period, eleven of 39 (28 %) in Group 1, two of 36 (6 %) in Group 2, and three of 23 (13 %) in Group 3 progressed to end-stage renal disease and were started on dialysis.

CONCLUSIONS

It appears that patients with lupus membranous GN have better renal prognosis than patients with idiopathic membranous GN. The renal prognosis for patients with pathological features of lupus membranous but no diagnosis of systemic lupus (lupus-like membranous GN) falls in between. Further studies are needed to determine if Group 3 patients can (a) definitively be classified as true idiopathic membranous GN or lupus membranous GN or (b) they have a separate disease from either M-type phospholipase A2 receptor membranous nephropathy or systemic lupus-induced membranous nephropathy.

Relapse and its remission in Japanese patients with idiopathic membranous nephropathy

BACKGROUND

The prognosis in patients with idiopathic membranous nephropathy (IMN) is diverse. However, the prognosis after relapse and factors affecting relapse remain unclear.

METHODS

A total of 146 Japanese patients with IMN who had been followed up for at least 3 years, or until end-stage renal failure or death were enrolled in this retrospective study. The initial clinicopathological factors were examined between the patients with and without relapse. The patients were assigned to two groups based on the electron microscopic findings: homogeneous type with synchronous electron-dense deposits and heterogeneous type with various phases of dense deposits.

RESULTS

A total of 105 of the 146 patients (72 %) achieved complete remission (CR) or incomplete remission (ICR) I after initial treatment. Twenty-six of the 105 patients relapsed after CR or ICR I (25 %). There were no differences in initial clinical findings or data between the patients with and without relapse, except for the higher degree of proteinuria at onset in patients with relapse. The relapse rate of the heterogeneous group (43 %) was higher than that in the homogeneous group (20 %). There were no significant associations between relapse rate and immunosuppressive therapy at onset. Eleven of 26 patients showing relapse (42 %) achieved CR or ICR I, which was lower than the rate for patients with initial remission.

CONCLUSION

Our results suggest that patients with relapse achieved CR or ICR I and that electron microscopic findings demonstrating heterogeneous type indicated susceptibility to relapse.

Depletion of B lymphocytes in idiopathic membranous glomerulopathy: results from patients with extended follow-up

Aims

To assess the long-term therapeutic benefit of temporary depletion of B lymphocytes in patients with idiopathic membranous glomerulopathy (MGN) and search for potential predictors of response.

Patients and Methods

The patients included had been diagnosed with biopsy-proven MGN in the absence of secondary causes. Estimated glomerular filtration rate should be above 30 ml/min/1.73 m² and 24-hour proteinuria 3 g/day or more. Patients who had been treated with cyclosporine or cytotoxic agents the year prior to study entry were excluded. Depletion of B cells was achieved with rituximab, which was administered intravenously for 4 consecutive weeks. Partial remission was defined as a >50% decrease in proteinuria with absolute proteinuria <3 g/day, while complete remission was defined as a >50% decrease in proteinuria and an absolute protein excretion <0.3 g/day.

Results

Twelve patients were studied (4 females/8 males) with a mean age of 51.3 years. No major adverse effects were observed. During a median follow-up time of 48 months, 11/12 (91.6%) patients achieved remission [7/12 (58.3%) complete remission and 4/12 (33.3%) partial remission], while 1 patient did not respond to therapy. Twelve months after therapy, 68.8% (p = 0.003) of cases had achieved partial and 28.4% complete remission. Measurements of lymphocyte subpopulations did not reveal any changes except for the B cell depletion. B cell infiltrates captured per mm³ of renal tissue in the diagnostic biopsy did not correlate with subsequent response.

Conclusion

Depletion of B cells in idiopathic MGN was well tolerated and resulted in significant and long-lasting response rates in a series of 12 patients.

Idiopathic membranous nephropathy: clinical and histologic prognostic features and treatment patterns over time at a tertiary referral center

BACKGROUND

Idiopathic membranous nephropathy (i-MN) is a leading cause of nephrotic syndrome in adults and results in end-stage renal disease in approximately one third of patients. There are few large, long-term US studies evaluating clinical and histologic prognostic factors in i-MN.

METHODS

We describe 132 patients with biopsy-proven i-MN who were followed for a mean period of 68 months at our tertiary referral center from 1977 to 2009, and we analyzed clinical and histologic features that predicted renal outcomes.

RESULTS

The presence of hypertension and treating physician's decision to institute immunosuppression were negative predictors of attaining complete or partial remission. Among clinical variables, impaired renal function (eGFR <60 ml/min/1.73 m(2)) at time of presentation was the only variable at presentation associated with an increased risk of reaching end-stage renal disease. The use of statins and RAAS blockers were protective. The choice of corticosteroids as the initial immunosuppressive agent by referring physicians decreased over time but even in the most recent era (2000-2008) was significant (33%).

CONCLUSION

Renal function at presentation and non-white race were the main predictors of a worse renal outcome. Corticosteroid therapy is still being adopted as first-line therapy in a significant number of patients in this era. The development of guidelines may help clarify the treatment strategies of i-MN.

Association of STAT4 polymorphisms with susceptibility to primary membranous glomerulonephritis and renal failure

BACKGROUND

Membranous glomerulonephritis (MGN) is one of common causes of idiopathic nephrotic syndrome in adults, and 25% of MGN patients proceed to end-stage renal disease. STAT4 gene polymorphisms have been reported to be associated with many inflammatory diseases. The objective of this study was to clarify the relationship between STAT4 gene polymorphisms and the pathogenesis of MGN.

METHODS

We investigated the association of three STAT4 gene polymorphisms (rs3024912, rs3024908, and rs3024877) with the susceptibility to MGN in 403 Taiwanese populations (138 MGN patients and 265 controls).

RESULTS

The results indicated that the statistically significant difference in genotype frequency distribution was found at rs3024908 SNP in MGN patients and control groups (p=0.014). In addition, the individuals with the GG genotype at rs3024912 SNP may have a higher risk in kidney failure of MGN patients (adjusted odds ratio [OR]=3.255; 95% confidence interval [CI]=1.155-9.176, p=0.026).

CONCLUSIONS

Our data provide a new information that the STAT4 (rs3024912 and rs3024908) polymorphisms may be the underlying cause of MGN, and these polymorphisms revealed by this study warrant further investigation.

Effect of IL-6 C-572G polymorphism on idiopathic membranous nephropathy risk in a Han Chinese population

Membranous glomerulonephritis (MGN) is viewed as an immune-mediated glomerular disease, with immunologic expression occurring in genetically susceptible persons. The cytokine interleukin-6 (IL-6) gene polymorphism is known to impair intracellular signaling pathways following adaptive immune response. Our study gauged the effects of IL-6 C-572G (rs1800796) single nucleotide polymorphism (SNP) on MGN among Taiwan's Han Chinese population, as analyzed in 265 controls and 106 MGN patients. Genotyping for IL-6 C-572G SNP was performed by restriction fragment length polymorphism assay. Data showed stark differences in genotype and allele frequency distributions at IL-6 C-572G SNP between MGN patients and controls (p = 1.6E-04 and 1.7E-04, respectively). People with C allele or with CC genotype at IL-6 C-572G SNP showed higher risk of MGN (odds ratio = 2.42 and 2.71, respectively; 95% confidence interval = 1.51-3.87 and 1.60-4.60, respectively). These point to IL-6 C-572G polymorphism as the underlying cause of MGN; polymorphism merits further investigation.

Lack of association between transient receptor potential cation channel 6 polymorphisms and primary membranous glomerulonephritis

Membranous glomerulonephritis (MGN) is one common cause of idiopathic nephrotic syndrome. Transient receptor potential cation channel 6 (TRPC6) has been identified as causing a familial form of progressive focal and segmental glomerulosclerosis. The objective was to clarify the relationship between TRPC6 polymorphisms and MGN. We recruited a cohort of 134 biopsy-diagnosed MGN patients and 265 healthy subjects. Genotyping of TRPC6 polymorphisms was performed using allele-specific polymerase chain reaction methods. We then analyzed associations between TRPC6 gene polymorphisms and clinical manifestations and pathogenesis of MGN. There was no statistically significant difference of TRPC6 gene rs3824935 C/T, rs17096918 C/T, and rs4326755 A/G polymorphisms between controls and patients with MGN. There was no statistical significance of allele frequencies in these two groups. The characteristics of clinical parameters in TRPC6 gene (rs3284935) C/T polymorphism revealed no difference except proteinuria (p < 0.0005) between CC and non-CC genotype in MGN patients. Besides, no apparent statistically significant differences of rs17096918 C/T (TT and non-TT) and rs4326755 A/G (AA and non-AA) polymorphisms between genotypes were found in the clinical parameters. There is no different genotype distribution between normal controls and patients with MGN of TRPC6 gene. The data also show that TRPC6 gene may not be associated with disease clinical course of MGN.

Etiology and clinical characteristics of membranous nephropathy in Chinese patients

BACKGROUND

Membranous nephropathy (MN) is a common cause of proteinuria and can be subdivided into idiopathic and secondary classifications. Most patients with MN present with associated systemic diseases that need to be identified before appropriately diagnosing idiopathic MN. However, the cause and clinical characteristics of MN in Chinese patients have not been investigated.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Patients with biopsy-proven MN at the Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.

OUTCOME

The diagnosis of idiopathic and secondary MN was based on clinical, initial laboratory, and histological findings.

RESULTS

390 patients with MN were identified from 1985 to 2005. Of 390 patients with MN, 124 (31.8%) had idiopathic MN and 266 had secondary MN (68.2%). Of patients with idiopathic MN, 75 (60.5%) were men and 49 (39.5%) were women. Mean age was 43.9 +/- 13.2 years (range, 14 to 78 years). Common presentations of idiopathic MN were 60.5% with proteinuria (39.5% of whom presented with nephrotic syndrome), 29.8% with hypertension, 17.7% with hematuria, and 0.8% with decreased kidney function. In patients with secondary MN, causes were autoimmune diseases (73.3%), infections (17.7%), tumors (4.5%), and drugs or toxins (4.5%). Systemic lupus erythematosus was the most common autoimmune disease (predominately in younger women). Hepatitis B predominated in younger men. Greater levels of proteinuria were found in patients who presented with drugs or toxins compared with patients with other secondary MNs (P < 0.05).

LIMITATIONS

Not all patients underwent all tests, particularly serum tumor markers, hepatitis C virus antibody, and hepatitis C virus RNA tests.

CONCLUSION

Proteinuria was a common presentation in patients with idiopathic MN, which was predominately found in middle-aged to elderly men. Secondary MN was more common than idiopathic MN, and most secondary MN diagnoses were secondary to systemic lupus erythematosus and hepatitis B infection.

Glomerular clusterin is associated with PKC-alpha/beta regulation and good outcome of membranous glomerulonephritis in humans

Mechanisms for human membranous glomerulonephritis (MGN) remain elusive. Most up-to-date concepts still rely on the rat model of Passive Heymann Nephritis that derives from an autoimmune response to glomerular megalin, with complement activation and membrane attack complex assembly. Clusterin has been reported as a megalin ligand in immunodeposits, although its role has not been clarified. We studied renal biopsies of 60 MGN patients by immunohistochemistry utilizing antibodies against clusterin, C5b-9, and phosphorylated-protien kinase C (PKC) isoforms (pPKC). In vitro experiments were performed to investigate the role of clusterin during podocyte damage by MGN serum and define clusterin binding to human podocytes, where megalin is known to be absent. Clusterin, C5b-9, and pPKC-alpha/beta showed highly variable glomerular staining, where high clusterin profiles were inversely correlated to C5b-9 and PKC-alpha/beta expression (P=0.029), and co-localized with the low-density lipoprotein receptor (LDL-R). Glomerular clusterin emerged as the single factor influencing proteinuria at multivariate analysis and was associated with a reduction of proteinuria after a follow-up of 1.5 years (-88.1%, P=0.027). Incubation of podocytes with MGN sera determined strong upregulation of pPKC-alpha/beta that was reverted by pre-incubation with clusterin, serum de-complementation, or protein-A treatment. Preliminary in vitro experiments showed podocyte binding of biotinilated clusterin, co-localization with LDL-R and specific binding inhibition with anti-LDL-R antibodies and with specific ligands. These data suggest a central role for glomerular clusterin in MGN as a modulator of inflammation that potentially influences the clinical outcome. Binding of clusterin to the LDL-R might offer an interpretative key for the pathogenesis of MGN in humans.

Lamivudine in hepatitis B-associated membranous nephropathy

BACKGROUND

Although lamivudine is effective for treatment of chronic hepatitis B (HBV) infection, its potential therapeutic impact on HBV-related membranous nephropathy (MN) in adults has not been characterized.

METHODS

We treated 10 HBsAg-positive patients with biopsy-proven MN, elevated serum alanine aminotransferase (ALT), and HBV-DNAemia (group 1), and compared their clinical course with 12 patients diagnosed to have HBV infection, elevated serum ALT, and MN in the pre-lamivudine era (group 2).

RESULTS

Baseline demographic and clinical parameters were not different between the 2 groups. In group 1, lamivudine treatment was associated with significant reduction in proteinuria, increase in serum albumin, normalization of ALT levels, and disappearance of circulating HBV-DNA during the first year. Four (40%) and 6 (60%) patients went into complete remission (proteinuria <0.3 g/d) at 6 and 12 months, respectively. In group 2, significant proteinuria persisted during the first year. One (8.3%) and 3 (25%) patients went into remission. Cumulative 3-year renal survival [using end-stage renal disease (ESRD) as primary end point] was 100% in group 1 and 58% in group 2 (P= 0.024, log rank test). Blood pressure control reached the target of below 130/85 mm Hg in both groups. Lamivudine was well tolerated and not associated with any adverse events. Hepatic decompensation or malignancy was not observed during follow-up in both groups.

CONCLUSION

HBV-related MN leads to ESRD in a significant proportion of patients before the advent of antiviral therapy. Lamivudine treatment improves renal outcome in HBV carriers with MN and evidence of liver disease.

Idiopathic Membranous Nephropathy: Outline and Rationale of a Treatment Strategy

Idiopathic membranous nephropathy is a common cause of nephrotic syndrome. The treatment of patients with idiopathic membranous nephropathy is heavily debated. Based on literature data and our own experience, we propose a rational treatment strategy. Patients with renal insufficiency (serum creatinine level > 1.5 mg/dL [> 135 micromol/L]) are at greatest risk for the development of end-stage renal disease and should receive immunosuppressive therapy. In patients with normal renal function (serum creatinine level < 1.5 mg/dL [< 135 micromol/L]), risk for developing end-stage renal disease can be estimated by measuring urinary excretion of beta2-microglobulin or alpha1-microglobulin and immunoglobulin G. For low-risk patients, a wait-and-see policy is advised. High-risk patients likely benefit from immunosuppressive therapy. Currently, combinations of steroids with chlorambucil or cyclophosphamide are the best studied. We prefer cyclophosphamide in view of its fewer side effects. Cyclosporine may be an alternative option in patients with well-preserved renal function, although long-term data are lacking. Other immunosuppressive agents, such as mycophenolate mofetil or rituximab, currently are under study; however, data are insufficient to support their routine use.

Membranous nephropathy associated with acute myeloid leukemia

Membranous nephropathy is the most common cause of adult-onset idiopathic nephrotic syndrome. Glomerular disease has been reported to occur in association with a wide variety of malignancies, particularly carcinomas and lymphomas. With the case reported here, we relate acute myeloid leukemia with membranous glomerulonephritis, depending on the previous literature reports about the association of malignancies and glomerulopathies.

Recent developments in the management of membranous nephropathy

Idiopathic membranous nephropathy is one of the most commonly encountered forms of nephrotic syndrome in adults. The natural history of the disease, observed in a small sample of untreated patients, reveals that a large proportion of patients experience spontaneous remission, whereas approximately one third of them progress towards renal insufficiency, and thus require dialysis. Hence, several attempts to treat this condition have been investigated and several protocols, based on different combinations of corticosteroids and/or immunosuppressive agents, have been proposed. However, none of these protocols has been uniformly adopted by renal physicians, either because of no or limited efficacy of most of them, or due to the potential of short- and long-term untoward effects. In this review, we examine the available data on the natural course of the disease and the possibility of identifying clinical and laboratory characteristics that could help to predict the course of membranous nephropathy. We also summarise the results of the most relevant clinical trials, and offer an updated meta-analysis of treatment studies, including the latest data on cyclosporin.

Pathologic findings of initial biopsies reflect the outcomes of membranous nephropathy

BACKGROUND

A considerable diversity of prognosis is seen with idiopathic membranous nephropathy (IMN). The initial factors affecting long-term outcome remain unclear.

METHODS

We studied retrospectively 105 patients with IMN who had been followed up for at least 5 years, or until end-stage renal failure (ESRF) (primary outcome), or death (secondary outcome). We analyzed the initial clinicopathologic factors affecting primary and secondary outcomes. We assigned the patients to two groups and one subgroup, based on the electron microscopic findings. The groupings were: homogeneous type with synchronous electron dense deposits; homogeneous type with large dense deposits (deep subgroup); and heterogeneous type with various phases of dense deposits.

RESULTS

No differences in the initial clinicopathologic states were seen between the homogeneous (N= 60) and heterogeneous types (N= 45), apart from hypertension and disease history before biopsy. In the homogeneous type, only one patient developed ESRF, which was drug-induced, and remission occurred earlier than in the heterogeneous type. With regard to secondary outcomes, increased age, male gender, heterogeneous type, and deep subgroup were independent risk factors. There were no significant differences attributable to therapeutic regime with respect to primary or secondary outcome in either group.

CONCLUSION

Our results indicate that an electron microscopic classification, at initial biopsy, as heterogeneous type or deep subgroup type with dense deposits are independent indicators of poor prognosis in IMN.

Depletion of clusterin in renal diseases causing nephrotic syndrome

BACKGROUND

Clusterin is a lipoprotein that has anti-complement effects in membranous nephropathy (MN). In focal segmental glomerulosclerosis (FSGS), it inhibits permeability plasma factor activity and could influence proteinuria. Moreover, with aging, knockout mice for clusterin develop a progressive glomerulopathy with sclerosis.

METHODS

Since little is known about clusterin metabolism in humans, we determined clusterin levels and composition in the sera and urine of 23 patients with MN, 25 with FSGS and 23 with steroid-responsive nephrotic syndrome (NS). Renal localization was evaluated by immunofluorescence and morphometry.

RESULTS

Serum clusterin was markedly reduced in active MN, in FSGS and in children with NS compared to controls; after stable remission of proteinuria, nearly normal levels were restored. Among various biochemical variables, serum clusterin was inversely correlated with hypercholesterolemia. Urinary clusterin, representing a 0.01 fraction of serum, was higher in the urine from normal subjects and FSGS patients in remission with proteinuric MN, FSGS and idiopathic NS; clusterin was inversely correlated with proteinuria. In all cases, urinary and serum clusterin was composed of the same 80 kD isoforms. Finally, a decrease in focal segmental or global clusterin staining was found in FSGS glomeruli, especially in areas of sclerosis. Instead, in MN an overall increment of staining was observed that ranged from mild/focal to very intense/diffuse.

CONCLUSIONS

The overall pool of clusterin is reduced in glomerular diseases causing nephrotic syndrome, with hypercholesterolemia appearing as the unifying feature. Depletion of clusterin should negatively affect the clinical outcome in nephrotic patients and efforts should be aimed at normalizing clusterin overall pool.

Treatment of idiopathic membranous nephropathy (IMN)

The best treatment of idiopathic membranous nephropathy remains an area of clinical controversy. At the moment only patients with nephrotic syndrome and/or declining renal function should be treated. Despite the negative trials, prolonged oral administration of corticosteroids alone may be a safe and an effective first-line treatment in nephrotic patients. If corticosteroids are ineffective, prolonged use of cyclosporine in low-doses can be recommended as an alternative treatment, that diminishes rapidly proteinuria in the majority of patients. Both treatments (intravenous high doses of corticosteroids and cyclosporine) may also be effective in patients with declining renal function. Because of their toxicity, the routine use of alkylating agents for patients with nephrotic syndrome is not justified. They may be retained for patients, in whom other treatment modalities have failed. Chlorambucil may be preferred over cyclophosphamide since it carries less toxicity. A lower dose of chlorambucil, than that usually suggested, for a short period of time seems to be prudent in an effort to avoid serious side-effects.