Controversies in the treatment of idiopathic membranous nephropathy

Clinical efficacy and safety of beraprost sodium in the treatment of nephrotic syndrome: A meta-analysis

BACKGROUND

Beraprost sodium has been shown to have positive effects in the kidney; however, its efficacy and safety in the treatment of nephrotic syndrome (NS) are currently unknown. Therefore, the aim of this meta-analysis was to evaluate the clinical efficacy and safety of beraprost sodium in the treatment of NS.

METHODS

We systematically searched EMBASE, PubMed, MEDLINE, China National Knowledge Internet (CNKI), Chinese Biomedical Database (CBM), and Wanfang database for articles from their inception to August 2022.

RESULTS

A total of 12 randomized controlled trials (RCTs) involving 1200 subjects were collected for careful evaluation. The meta-analysis indicated that compared with the controls, combination therapy with berprost sodium could remarkably improve the total effective rate (odds ratio 4.21, 95% confidence interval [CI]: 2.87 to 7.25) and reduce 24 hours proteinuria (mean difference [MD] -1.03, 95% CI: -1.26 to -0.8), serum creatinine (MD -18.39; 95% CI: -27.81 to -8.98), blood urea nitrogen (MD -1.43,95% CI: -1.94 to -0.92), serum total cholesterol (MD -1.24; 95% CI: -1.36 to -1.11), and triglyceride (MD -0.69; 95% CI: -1.03 to -0.35), and increase serum albumin (MD 4.96, 95% CI: 2.98 to 6.93). But the adverse effects of dizziness and headache were higher (RD = 0.05. 95% CI: 0.02 to 0.08).

CONCLUSION

For NS patients, combination therapy with beraprost sodium can achieve higher clinical efficacy and significant improvement in renal function than conventional therapy.

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.

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.

Tetrandrine may treat membranous glomerulopathy via P13K/Akt signaling pathway regulation: therapeutic mechanism validation using Heymann nephritis rat model

Membranous glomerulopathy (MGN) is an autoimmune kidney disease that is the primary cause of nephrotic syndrome (NS) in adults. Tetrandrine, a bisbenzylisoquinoline alkaloid, is known to have numerous pharmacological effects. In this study, network pharmacology analysis and experimental validation were conducted to analyze the mechanisms by which tetrandrine functions as a therapeutic intervention for MGN. A systematic network pharmacology method was applied to identify potential targets and determine the therapeutic mechanism of tetrandrine in MGN treatment. A Heymann nephritis (HN) rat model was developed to assess the therapeutic effects of tetrandrine on NS and validate the predicted molecular mechanisms. We obtained 86 potential targets of tetrandrine for the treatment of NS. In vivo experiments showed that tetrandrine could reduce the 24-h urine protein content, decrease glomerular basement membrane proliferation, and significantly decrease thylakoid stroma and cell proliferation in the HN rat kidney tissue. Moreover, tetrandrine suppressed kidney cell apoptosis and upregulated the expression of nephrin and podocin in HN model rats. qRT-PCR results revealed that tetrandrine inhibited IL-1β, TNFα, and MCP-1 levels in HN model rats. Western blot results indicated that tetrandrine can protect against MGN via the PI3K/Akt signaling pathway. Thus, by using a combination of network and experimental pharmacology methods, we demonstrate that tetrandrine can treat MGN via the PI3K/Akt signaling pathway and provide novel insights into the mechanisms underlying tetrandrine-mediated management of MGN.

Seropositive PLA2R-associated membranous nephropathy but biopsy-negative PLA2R staining

BACKGROUND

Serum phospholipase A2 receptor (PLA2R) antibody (SAb) and glomerular deposits of PLA2R antigen (GAg) have been tested widely in idiopathic membranous nephropathy (MN). Recently, we noticed a special form of PLA2R-associated MN with positive circulating PLA2R antibody but negative PLA2R deposits in the glomeruli by immunofluorescence on frozen tissue (IF-F). The significance of this form of PLA2R-associated MN is yet to be elucidated. This study aimed to explore the clinicopathological features of these PLA2R-associated MN patients.

METHODS

This study enrolled 229 biopsy-proven PLA2R-associated MN patients with SAb+. SAb was measured by enzyme-linked immunosorbent assay, and GAg was detected by IF-F. These patients were divided into SAb+/GAg+ and SAb+/GAg- groups. Clinicopathological characteristics of SAb+/GAg+ and SAb+/GAg- PLA2R-associated MN patients were compared. PLA2R antigens of 19 SAb+/GAg- PLA2R-associated MN patients were verified by immunohistochemistry on paraffin tissue (IHC-P).

RESULTS

Among 229 SAb+ PLA2R-associated MN patients, 210 (91.70%) were GAg+ and 19 (8.3%) were GAg-. These 19 SAb+/GAg- PLA2R-associated MN patients presented positive PLA2R deposits by IHC-P. Compared with SAb+/GAg+ PLA2R-associated MN patients, SAb+/GAg- PLA2R-associated MN patients had higher levels of serum PLA2R antibody (P = 0.004), increased proteinuria (P = 0.008), lower serum albumin (P = 0.019), more prominent chronic pathological lesions in terms of glomerulosclerosis score (P = 0.025), interstitial fibrosis score (P = 0.016), tubular atrophy score (P = 0.010) and total renal chronicity score (P = 0.010), and were more likely to be accompanied by focal segmental glomerulosclerosis (P = 0.014). Higher SAb level was associated with the total renal chronicity score (odds ratio per 100 RU/mL, 1.16; 95% confidence interval 1.01-1.33; P = 0.033).

CONCLUSIONS

PLA2R-associated MN patients with seropositive PLA2R antibody but negative PLA2R deposits in the glomeruli by IF-F have higher levels of SAb and worse clinicopathological manifestations compared with their double-positive counterparts. IHC-P can be an alternative technique to reveal PLA2R glomerular deposits.

A Point-of-Care Immunosensor Based on a Quartz Crystal Microbalance with Graphene Biointerface for Antibody Assay

We present a sensitive and low-cost immunoassay, based on a customized open-source quartz crystal microbalance coupled with graphene biointerface sensors (G-QCM), to quantify antibodies in undiluted patient serum. We demonstrate its efficacy for a specific antibody against the phospholipase A2 receptor (anti-PLA2R), which is a biomarker in primary membranous nephropathy. A novel graphene-protein biointerface was constructed by adsorbing a low concentration of denatured bovine serum albumin (dBSA) on the reduced graphene oxide (rGO) sensor surface. The dBSA film prevents the denaturation of the protein receptor on the rGO surface and serves as the cross-linker for immobilization of the receptor for anti-PLA2R antibodies on the surface. The detection limit and selectivity of this G-QCM biosensor was compared with a commercial QCM system. The G-QCM immunoassay exhibited good specificity and high sensitivity toward the target, with an order of magnitude better detection limit (of 100 ng/mL) compared to the commercial system, at a fraction of the cost and with considerable time saving. The results obtained from patient sera compared favorably with those from enzyme-linked immunosorbent assay, validating the feasibility of use in clinical applications. The multifunctional dBSA-rGO platform provides a promising biofunctionalization method for universal immunoassay and biosensors. With the advantages of inexpensive, rapid, and sensitive detection, the G-QCM sensor and instrument form an effective autoimmune disease screening tool.

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.

Efficacy and safety of rituximab in the treatment of membranous nephropathy: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Rituximab (RTX) is considered to be a promising drug for curing membranous nephropathy. However, the efficacy and safety of RTX in treating membranous nephropathy remain uncertain. This meta-analysis aimed to investigate the efficacy and safety of RTX in patients with membranous nephropathy.

METHODS

A literature search was performed using Pubmed, Embase, OVID, and Cochrane Library and randomized controlled trials (RCTs) case-controls and cohort studies published till 30 July 2019 were assessed. The studies assessing the efficacy and safety of RTX in patients with membranous nephropathy were included.

RESULTS

Eight relevant trials involving 542 patients were included in the meta-analysis. It was found that RTX did not significantly improve serum albumin levels and e-GFR when compared with the control group (including cyclosporine and cyclophosphamide, chlorambucil, prednisone, non-immunosuppressive anti-proteinuria treatment), serum albumin levels (OR = 0.31, 95%CI-0.12-0.74, P = .15), e-GFR (OR = -1.49, 95%CI-17.14-14.17, P = .85). However, RTX did reduce the serum creatinine (OR = -0.01, 95%CI-0.36-0.34, P = .95) and urinary protein (OR = -2.39, 95%CI -7.30 -2.53, P = .34) levels. Also, in comparison to the control group, RTX did improve the total remission rate (OR = 1.63, 95%CI 0.48-5.54, P = .43), achieve a higher rate of complete remission (OR = 2.54, 95%CI 1.65-3.90, P < .01) and also reduced the amount of M-type phospholipase A2 receptor-Antibody depletion in patients (OR = 5.59, 95%CI 1.81-17.2, P = .003). RTX-related adverse events were mostly mild (most infusion-related reactions) in nature and serious adverse events were rare.

CONCLUSION

RTX proved to be efficient, well-tolerated and a safe drug in the treatment of membranous nephropathy. Most patients reach complete remission during the follow-up period, and relapse is rare. RTX may turn out to be promising in membranous nephropathy patients.

Clinical observation and analysis of thyroid hormone levels in patients with idiopathic membranous nephropathy

We sought to investigate the effect of total triiodothyronine (TT3) reduction in the follow-up of patients with idiopathic membranous nephropathy (IMN). A total of 121 patients were enrolled and classified into a low TT3 group or a normal group. Clinical indicators were compared between the groups, and changes in estimated glomerular filtration rate (eGFR), albumin (ALB), thyroid-stimulating hormone, serum creatinine, total protein, total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) during follow-up were analysed. In the analysis by TT3 level, ALB was significantly lower in the low TT3 group (P < .05), while TC, TG, LDL-C, fibrinogen, and renal pathological staging were significantly higher in the low TT3 group (P < .05). Analysis of variance for repeated measurement during follow-up showed that there were no significant differences in eGFR and ALB between the groups. TC, TG, and LDL-C levels were significantly higher in the low TT3 group (P < .05). Approximately 37% of patients with IMN showed a decrease in TT3, which was accompanied by significantly decreased ALB level, higher pathological stage, and increased serum lipid level compared with patients having a normal TT3 level. The management of TT3, and appropriate intervention, may therefore help to prevent the kidney damage progress in patients with IMN.

Phospholipase A2 Receptor Antibody IgG4 Subclass Improves Sensitivity and Specificity in the Diagnosis of Idiopathic Membranous Nephropathy

AIMS

The aim of this study was to develop a new method for detecting anti-phospholipase A2 receptor-IgG4 to improve the sensitivity and specificity in the diagnosis of idiopathic membranous nephropathy (IMN).

METHODS

A highly sensitive quantitative assay was developed for the detection of serum anti-phospholipase A2 receptor-IgG4 with europium chelation by time-resolved fluoroimmunoassay (TRFIA), and a mouse anti-human IgG4 tracer was prepared using europium chelation for detection. The specificity and sensitivity of anti-phospholipase A2 receptor-IgG4 in the diagnosis of IMN were further assessed in patients with different kidney diseases.

RESULTS

The detection limit of anti-PLA2R-IgG4 was 0.69 ng/mL. The measurement range of anti-PLA2R-IgG4 TRFIA was 0.69-2,500 ng/mL. Mean serum anti-PLA2R-IgG4 was 21.27 ± 15.15 ng/mL in 45 healthy volunteers, 31.08 ± 18.17 ng/mL in 29 IgA nephropathy patients, 49.10 ± 34.32 ng/mL in 8 lupus nephropathy patients, and 10,324.11 ± 17,030.40 ng/mL in 30 IMN patients. The anti-PLA2R-IgG4 cutoff concentration was >161.2 ng/mL with the sensitivity of 90.0% and specificity of 100% in the diagnosis of IMN. However, the cutoff for other kidney diseases was lower than 161.2 ng/mL.

CONCLUSION

The serum anti-phospholipase A2 receptor IgG4 detected with the method developed in this study has higher sensitivity and higher specificity than total IgG in the diagnosis of IMN.

A novel Time-resolved Fluoroimmunoassay for the quantitative detection of Antibodies against the Phospholipase A2 Receptor

A highly sensitive time-resolved fluoroimmunoassay (TRFIA) was developed to quantify serum antibodies against the phospholipase A2 receptor (anti-PLA2R-IgG) for differential diagnosis of membranous nephropathy. Recombinant PLA2R (rPLA2R) was coated onto 96-well plates as a capture. A goat-anti-human IgG tracer was prepared with europium-chelate for detection. After bound/free separation by washing, the fluorescence counts of bound tracer were measured for quantifying serum anti-PLA2R-IgG concentration. A purified anti-PLA2R-IgG calibrator was first prepared for ensuring that consistent quantitative results could be obtained. The assay detection limit was 0.03 mg/L with linear measurement range of 0.03-340 mg/L. The intra- and inter-assay coefficients of variation (CVs) were 3.8% and 6.2%, respectively. The average serum anti-PLA2R-IgG concentration in 45 healthy volunteers, 31 IgA nephropathy, 9 lupus nephropathy, and 52 idiopathic membranous nephropathy patients was 0.53 ± 0.18 mg/L, 0.70 ± 0.41 mg/L, 1.08 ± 0.65 mg/L, and 9.00 ± 11.82 mg/L, respectively. The cut-off point for an abnormal anti-PLA2R-IgG concentration was defined as >0.89 mg/L. The positive rates in serum from patients with IgA nephropathy, lupus nephropathy, and idiopathic membranous nephropathy were 29.0%, 44.4%, and 88.5%, respectively. The availability of this quantitation method will facilitate the use of serum anti-PLA2R-IgG for diagnosing idiopathic membranous nephropathy.

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.

Treatment pattern in patients with idiopathic membranous nephropathy-practices in Sweden at the start of the millennium

Background

Idiopathic membranous nephropathy (MN) is one of the leading causes of nephrotic syndrome in adults and may result in end-stage renal disease (ESRD). In this retrospective study, we describe the outcomes and treatment patterns of patients with idiopathic MN in six nephrology clinics in the western part of Sweden.

Methods

Seventy-three consecutive patients with biopsy-proven MN in the years 2000–12 were classified as idiopathic, i.e. secondary forms were excluded. The patients were followed retrospectively for a mean period of 83 months and clinical data were collected through the medical files.

Results

A high proportion (88%) of the patients received supportive treatment with angiotensin-converting enzyme inhibition, angiotensin receptor blockade and/or statins. At the end of follow-up, 43 patients were in complete remission, 12 in partial remission, 10 patients had developed ESRD and 8 patients had on-going proteinuria. Fifty-one per cent of the patients received immunosuppressive therapy and the choice of therapy varied between and within the clinics. There was a tendency to initiate specific treatment at an early point instead of awaiting a possible spontaneous remission (21% of the patients), and non-recommended therapy such as corticosteroids only was used in a high proportion of these cases (47%).

Conclusions

Even though the treatment recommendations in idiopathic MN have not changed the last decade, the question of whom and when to treat seems to lead to uncertainty. Recent studies have presented promising results supporting the PLA₂R antibody the predictive marker needed for this patient group. The diverse treatment approach presented in this study might have resulted in a worse outcome than expected. Hopefully, unnecessary exposure to immunosuppressive therapy or delayed treatment can be avoided through better support, education and treatment forums, and thus result in an improved outcome.

A European multicentre and open-label controlled randomized trial to evaluate the efficacy of Sequential treatment with TAcrolimus-Rituximab versus steroids plus cyclophosphamide in patients with primary MEmbranous Nephropathy: the STARMEN study

BACKGROUND

Patients with primary membranous nephropathy (MN) and persistent nephrotic syndrome have a high risk of progression to end-stage renal disease. The Ponticelli protocol (steroids with alkylating agents) is the most effective immunosuppressive therapy for this condition, but it has severe adverse effects. Tacrolimus and rituximab have demonstrated efficacy for remission of nephrotic syndrome in MN with a safer profile. However, the published evidence is largely based on small or short-term observational studies, historical cohorts, comparisons with conservative therapy or clinical trials without appropriate control groups, and there is no head-to-head comparison with the Ponticelli protocol.

METHODS

The STARMEN randomized clinical trial will compare the efficacy of sequential tacrolimus-rituximab therapy with a modified Ponticelli protocol (steroids plus cyclophosphamide). The trial will also evaluate the role of antibodies against the M-type phospholipase A2 receptor (anti-PLA2R) and other antibodies as markers of response to treatment and long-term prognosis.

RESULTS

The trial has already started with 23 patients having been enrolled as of 1 April 2015, an estimated 21.7% of the estimated sample.

Immunosuppressive treatment for idiopathic membranous nephropathy in adults with nephrotic syndrome

BACKGROUND

Idiopathic membranous nephropathy (IMN) is the most common form of nephrotic syndrome in adults. The disease shows a benign or indolent course in the majority of patients, with a rate of spontaneous complete or partial remission of nephrotic syndrome as high as 30% or more. Despite this, 30% to 40% of patients progress toward end-stage kidney disease (ESKD) within five to 15 years. The efficacy and safety of immunosuppression for IMN with nephrotic syndrome are still controversial. This is an update of a Cochrane review first published in 2004.

OBJECTIVES

The aim of this review was to evaluate the safety and efficacy of immunosuppressive treatments for adult patients with IMN and nephrotic syndrome. Moreover it was attempted to identify the best therapeutic regimen, when to start immunosuppression and whether the above therapies should be given to all adult patients at high risk of progression to ESKD or only restricted to those with impaired kidney function.

SEARCH METHODS

We searched Cochrane Renal Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese databases, reference lists of articles, and clinical trial registries to June 2014. We also contacted principal investigators of some of the studies for additional information.

SELECTION CRITERIA

Randomised controlled trials (RCTs) investigating the effects of immunosuppression in adults with IMN and nephrotic syndrome.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, quality assessment, and data synthesis were performed using the 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.

MAIN RESULTS

Thirty nine studies with 1825 patients were included, 36 of these could be included in our meta-analyses. The data from two studies could not be extracted and one study was terminated due to poor accrual. Immunosuppression significantly reduced all-cause mortality or risk of ESKD ((15 studies, 791 patients): RR 0.58 (95% CI 0.36 to 0.95, P = 0.03) and risk of ESKD ((15 studies, 791 patients): RR 0.55, 95% CI 0.31 to 0.95, P = 0.03), increased complete or partial remission ((16 studies, 864 patients): RR 1.31, 95% CI 1.01 to 1.70, P = 0.04), and decreased proteinuria ((9 studies,(393 patients): MD -0.95 g/24 h, 95% CI -1.81 to -0.09, P = 0.03) at the end of follow-up (range 6 to 120 months). However this regimen was associated with more discontinuations or hospitalisations ((16 studies, 880 studies): RR 5.35, 95% CI 2.19 to 13.02), P = 0.0002). Combined corticosteroids and alkylating agents significantly reduced death or risk of ESKD ((8 studies, 448 patients): RR 0.44, 95% CI 0.26 to 0.75, P = 0.002) and ESKD ((8 studies, 448 patients): RR 0.45, 95% CI 0.25 to 0.81, P = 0.008), increased complete or partial remission ((7 studies, 422 patients): RR 1.46, 95% CI 1.13 to 1.89, P = 0.004) and complete remission ((7 studies, 422 patients): RR 2.32, 95% CI 1.61 to 3.32, P < 0.00001), and decreased proteinuria ((6 studies, 279 patients): MD -1.25 g/24 h, 95% CI -1.93 to -0.57, P = 0.0003) at the end of follow-up (range 9 to 120 months). In a population with an assumed risk of death or ESKD of 181/1000 patients, this regimen would be expected to reduce the number of patients experiencing death or ESKD to 80/1000 patients (range 47 to 136). In a population with an assumed complete or partial remission of 408/1000 patients, this regimen would be expected to increase the number of patients experiencing complete or partial remission to 596/1000 patients (range 462 to 772). However this combined regimen was associated with a significantly higher risk of discontinuation or hospitalisation due to adverse effects ((4 studies, 303 patients): RR 4.20, 95% CI 1.15 to 15.32, P = 0.03). Whether this combined therapy should be indicated in all adult patients at high risk of progression to ESKD or only restricted to those with deteriorating kidney function still remained unclear. Cyclophosphamide was safer than chlorambucil ((3 studies, 147 patients): RR 0.48, 95% CI 0.26 to 0.90, P = 0.02). There was no clear evidence to support the use of either corticosteroid or alkylating agent monotherapy. Cyclosporine and mycophenolate mofetil failed to show superiority over alkylating agents. Tacrolimus and adrenocorticotropic hormone significantly reduced proteinuria. The numbers of corresponding studies related to tacrolimus, mycophenolate mofetil, adrenocorticotropic hormone, azathioprine, mizoribine, and Tripterygium wilfordii are still too sparse to draw final conclusions.

AUTHORS' CONCLUSIONS

In this update, a combined alkylating agent and corticosteroid regimen had short- and long-term benefits on adult IMN with nephrotic syndrome. Among alkylating agents, cyclophosphamide was safer than chlorambucil. This regimen was significantly associated with more withdrawals or hospitalisations. It should be emphasised that the number of included studies with high-quality design was relatively small and most of included studies did not have adequate follow-up and enough power to assess the prespecified definite endpoints. Although a six-month course of alternating monthly cycles of corticosteroids and cyclophosphamide was recommended by the KDIGO Clinical Practice Guideline 2012 as the initial therapy for adult IMN with nephrotic syndrome, clinicians should inform their patients of the lack of high-quality evidence for these benefits as well as the well-recognised adverse effects of this therapy. Cyclosporine or tacrolimus was recommended by the KDIGO Clinical Practice Guideline 2012 as the alternative regimen for adult IMN with nephrotic syndrome; however, there was no evidence that calcineurin inhibitors could alter the combined outcome of death or ESKD.

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.

Immunopathogenesis of membranous nephropathy: an update

Membranous nephropathy (MN) is a non-inflammatory organ-specific autoimmune disease which affects the kidney glomerulus, resulting in the formation of immune deposits on the outer aspect of the glomerular basement membrane, complement-mediated proteinuria, and severe renal failure in 30% of patients. In the last 10 years, substantial advances have been made in the understanding of the molecular bases of MN, with the identification of several antigens and predisposing genes in children and adults. These ground-breaking findings already have a major impact on diagnosis and monitoring and to some extent on therapies. However, there is evidence that the disease is more complex and involves a variety of antigen-antibody systems and genes involved in immune response, progression, recovery, and protective mechanisms. We herein review these recent findings which open new perspectives of research. Understanding the complex pathogenesis of MN will offer many opportunities for future therapeutic interventions and will hopefully have a major impact on patient care. New insights into the molecular mechanisms of MN may also enlighten the pathogenesis of organ-specific autoimmune diseases.

Diagnostic value of phospholipase A2 receptor in idiopathic membranous nephropathy: a systematic review and meta-analysis

BACKGROUND

Detection of M-type phospholipase A2 receptor (PLA2R) can be used in serologic diagnosis of idiopathic membranous nephropathy (IMN), but there are limited data about the sensitivity and specificity of its diagnostic values.

METHODS AND RESULTS

Meta-analysis of diagnostic test studies assessing the values of PLA2R in diagnosis of IMN. MEDLINE, EMBASE, and CENTRAL databases and congress abstracts were searched for studies reporting the value of PLA2R to predict IMN. The quality of the studies was evaluated using the guidelines of the updated Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The results are summarized as sensitivity, specificity, and diagnostic odds ratio (OR). Data from 10 studies involving 1,550 participants were analyzed. Across all settings, the diagnostic OR for serum anti-PLA2R level to predict IMN at different stages was 247.41, with sensitivity of 0.69 and specificity of 0.99. The estimated sensitivity and specificity of serum anti-PLA2R level for diagnosis of IMN in the active stage were 74.0 and 95.0%, respectively, with diagnostic OR of 54.22. The estimated sensitivity and specificity of biopsy anti-PLA2R for diagnosis of IMN at different stages was 73.0 and 83.0%, respectively, with diagnostic OR of 13.75.

CONCLUSIONS

This meta-analysis shows that serum anti-PLA2R level is of diagnostic value for IMN in the active stage. Future large-cohort prospective studies are required to reveal the diagnostic value of circulating anti-PLA2R antibodies versus PLA2R antigens in kidney biopsy for IMN at different stages.

Phospholipase A2 receptor staining in pediatric idiopathic membranous glomerulopathy

BACKGROUND

Membranous glomerulopathy, though typically a disease of adults, does occur in children. Antiphospholipase A2 receptor (PLA2R) autoantibodies have recently been implicated as a causative agent in most cases of adult primary (idiopathic) membranous glomerulopathy. PLA2R staining of renal biopsies in two recent large case series of adults with primary membranous glomerulopathy showed a sensitivity of approximately 75 % for detecting primary membranous glomerulopathy. To our knowledge, this is the largest study of its kind to assess PLA2R staining in a pediatric population.

METHODS

Forty-one consecutive cases of pediatric membranous glomerulopathy were identified from our database, and clinical follow-up was performed to confirm primary membranous glomerulopathy. Twenty-two patients met inclusion criteria and are the subject of this report.

RESULTS

Granular, capillary loop immunofluorescence staining for immunoglobulin G (IgG) was present in 100 % of patients, and C3 staining was present in 77 %. PLA2R staining was identified in ten patients, providing a sensitivity of 45 % [confidence interval (CI) 25-67 %]. Bovine serum albumin staining was performed in all PLA2R-negative cases and showed no positivity. Morphologic findings associated with negative PLA2R staining included segmental membranous lesions, mesangial and subendothelial deposits, C1q and "full-house" staining, and lower-stage lesions by electron microscopy. At 38 months' average follow-up, all patients were still considered as having primary membranous glomerulopathy, with none developing a clinically detectable secondary etiology.

CONCLUSIONS

PLA2R staining sensitivity is much lower in the pediatric than the adult primary membranous glomerulopathy population. This finding suggests a more diverse and currently incompletely described set of etiologies for this disease in this group.

Mouse models of membranous nephropathy: the road less travelled by

Membranous nephropathy (MN) is a major cause of idiopathic nephrotic syndrome in adults, often progressing to end-stage kidney disease. The disease is mediated by IgG antibodies that form subepithelial immune complexes upon binding to antigens expressed by podocytes or planted in the subepithelial space. Subsequent activation of the complement cascade, podocyte injury by the membrane attack complex and the expansion of the glomerular basement membrane cause proteinuria and nephrotic syndrome. The blueprint for our current understanding of the pathogenic mechanisms of MN has largely been provided by studies in rat Heymann nephritis, an excellent animal model that closely replicates human disease. However, further progress in this area has been hindered by the lack of robust mouse models of MN that can leverage the power of genetic approaches for mechanistic studies. This critical barrier has recently been overcome by the development of new mouse models that faithfully recapitulate the clinical and morphologic hallmarks of human MN. In these mouse models, subepithelial ICs mediating proteinuria and nephrotic syndrome are induced by injection of cationized bovine serum albumin, by passive transfer of heterologous anti-podocyte antibodies, or by active immunization with the NC1 domain of α3(IV) collagen. These mouse models of MN will be instrumental for addressing unsolved questions about the basic pathomechanisms of MN and also for preclinical studies of novel therapeutics. We anticipate that the new knowledge to be gained from these studies will eventually translate into much needed novel mechanism-based therapies for MN, more effective, more specific, and less toxic.

Immunosuppression for membranous nephropathy: a systematic review and meta-analysis of 36 clinical trials

BACKGROUND AND OBJECTIVES

The efficacy and safety of immunosuppression for idiopathic membranous nephropathy (IMN) with nephrotic syndrome are still controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was performed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Cochrane Library, PUBMED, EMBASE, Chinese Database, and Clinical Trial Registries (June 2012) were searched to identify RCTs investigating the effect of immunosuppression on adults with IMN and nephrotic syndrome.

RESULTS

This review was an update (36 RCTs, 1762 participants) of the 2004 version (18 RCTs, 1025 participants). Immunosuppression significantly reduced all-cause mortality or ESRD (15 RCTs, 791 participants; risk ratio, 0.58 [95% confidence interval, 0.36-0.95]; P=0.03). However, the result was not consistent when prespecified subgroup analyses were undertaken. Immunosuppression increased complete or partial remission (CR + PR) (16 RCTs, 864 participants; 1.31 [1.01-1.70]; P=0.04) but resulted in more withdrawals or hospitalizations (16 RCTs, 880 participants; 5.35 [2.19-13.02]; P=0.002). Corticosteroids combined with alkylating agents significantly reduced all-cause mortality or ESRD (8 RCTs, 448 participants; 0.44 [0.26-0.75]; P=0.002) and increased CR + PR (7 RCTs, 422 participants; 1.46 [1.13-1.89]; P=0.004) but led to more adverse events (4 RCTs, 303 participants; 4.20 [1.15-15.32]; P=0.03). Cyclophosphamide was safer than chlorambucil (3 RCTs, 147 participants; 0.48 [0.26-0.90]; P=0.02). Cyclosporine and mycophenolate mofetil failed to show superiority over alkylating agents. Tacrolimus and adrenocorticotropic hormone significantly reduced proteinuria.

CONCLUSIONS

Alkylating agents plus corticosteroids had long-term and short-term benefits for adult IMN, but resulted in more withdrawals or hospitalizations.

[Pathophysiology of extramembranous glomerulopathies. Fifty years of progress, from laboratory to patient]

Membranous nephropathy (MN) is a kidney disease characterized by deposition of immune complexes and complement on the outer aspect of the glomerular capillary wall. It is responsible for a loss of serum proteins in the urine and kidney failure. During the last ten years, considerable progress has occurred in the understanding of the molecular bases of the disease with the description of three distinct mechanisms in humans. In the neonatal allo-immune form, antibodies are directed against neutral endopeptidase (NEP), a podocyte antigen absent in the mothers who become immunized against this antigen expressed by placenta cells during pregnancy. NEP was the first podocyte antigen to be identified in MN. Most adult forms of MN are autoimmune diseases without identified etiology (primary MN), linked to the production of antibodies raised against another podocyte antigen, the type-M phospholipase A2 receptor (PLA2R1). Anti-PLA2R1 antibodies are detected in 70 to 80% of patients before any immunosuppressive treatment, and only occasionally in secondary forms of MN, variants of PLAR1 and HLA-DQA1 genes are very significantly associated with occurrence of primary MN in Caucasians. The third mechanism is characterized by immunization against a foreign protein, cationic bovine serum albumin (BSA), which is involved in rare forms of MN during early childhood. This finding points to a possible role of food and environmental antigens in membranous nephropathy.

Kidney biopsy is a sensitive tool for retrospective diagnosis of PLA2R-related membranous nephropathy

BACKGROUND

Antibodies against M-type phospholipase A2 receptor (PLA2R) are serological markers of disease activity in patients with idiopathic membranous nephropathy (iMN). To determine the most sensitive test for the diagnosis of PLA2R-related membranous nephropathy (MN) irrespective of sampling time, we investigated the presence of PLA2R in glomerular immune deposits and assessed circulating anti-PLA2R antibodies in a retrospective cohort of Czech patients with idiopathic, lupus and other few secondary MN.

METHODS

We tested archival paraffin-embedded kidney biopsies of 84 consecutive patients with biopsy-proven MN, for the presence of PLA2R in glomerular immune deposits and we measured circulating anti-PLA2R antibodies using the indirect immunofluorescence test, all reagents being commercially available.

RESULTS

In 45 of 65 (69%) patients with iMN, PLA2R was detected in a finely granular pattern in sub-epithelial deposits along glomerular capillary loops. Circulating anti-PLA2R antibodies were detected in 20 of 31 (65%) sera from patients sampled during active disease. Six patients with active disease were negative for circulating anti-PLA2R antibodies despite PLA2R antigen positivity in the kidney biopsies. Only 8 of 37 (22%) sera sampled at the time of remission were PLA2R positive while PLA2R antigen was found in 22 of the 37 (59%) corresponding biopsies. PLA2R was found in immune deposits in 3 patients with secondary MN (2 with hepatitis B, and 1 with sarcoidosis) but in none of the 16 patients with lupus.

CONCLUSIONS

In case of delayed serum sampling, assessment of PLA2R antigen in biopsy specimens is more sensitive than the serological test for the diagnosis of PLA2R-related MN which can be established retrospectively.

Antioxidants in kidney diseases: the impact of bardoxolone methyl

Drugs targeting the renin-angiotensin-aldosterone system (RAAS) are the mainstay of therapy to retard the progression of proteinuric chronic kidney disease (CKD) such as diabetic nephropathy. However, diabetic nephropathy is still the first cause of end-stage renal disease. New drugs targeted to the pathogenesis and mechanisms of progression of these diseases beyond RAAS inhibition are needed. There is solid experimental evidence of a key role of oxidative stress and its interrelation with inflammation on renal damage. However, randomized and well-powered trials on these agents in CKD are scarce. We now review the biological bases of oxidative stress and its role in kidney diseases, with focus on diabetic nephropathy, as well as the role of the Keap1-Nrf2 pathway and recent clinical trials targeting this pathway with bardoxolone methyl.

Murine membranous nephropathy: immunization with α3(IV) collagen fragment induces subepithelial immune complexes and FcγR-independent nephrotic syndrome

Membranous nephropathy (MN) is a leading cause of nephrotic syndrome in adults and a significant cause of end-stage renal disease, yet current therapies are nonspecific, toxic, and often ineffective. The development of novel targeted therapies requires a detailed understanding of the pathogenic mechanisms, but progress is hampered by the lack of a robust mouse model of disease. We report that DBA/1 mice as well as congenic FcγRIII(-/-) and FcRγ(-/-) mice immunized with a fragment of α3(IV) collagen developed massive albuminuria and nephrotic syndrome, because of subepithelial deposits of mouse IgG and C3 with corresponding basement membrane reaction and podocyte foot process effacement. The clinical presentation and histopathologic findings were characteristic of MN. Although immunized mice produced genuine anti-α3NC1 autoantibodies that bound to kidney and lung basement membranes, neither crescentic glomerulonephritis nor alveolitis ensued, likely because of the predominance of mouse IgG1 over IgG2a and IgG2b autoantibodies. The ablation of activating IgG Fc receptors did not ameliorate injury, implicating subepithelial deposition of immune complexes and consequent complement activation as a major effector pathway. We have thus established an active model of murine MN. This model, leveraged by the availability of genetically engineered mice and mouse-specific reagents, will be instrumental in studying the pathogenesis of MN and evaluating the efficacy of novel experimental therapies.

[Idiopathic and secondary membranous nephropathies]

Antibodies to neutral endopeptidase, a podocyte protein, are responsible for rare alloimmune neonatal membranous nephropathy that develops in children from neutral endopeptidase-deficient mothers. Neutral endopeptidase was the first podocyte antigen described in human membranous nephropathy. PLA2R1, the type-M receptor of soluble phospholipase A2, is a major target antigen in so-called idiopathic membranous nephropathy in adults. Antibodies to PLA2R1 are detected in 60 to 80% of patients before immunosuppressive treatment, and are only occasionally found in secondary membranous nephropathy. To date, they have not been detected in other pathological conditions and in healthy individuals. PLA2R1 and HLA-DQA1 gene variants defined by single nucleotide polymorphisms are strongly associated with idiopathic membranous nephropathy in patients of white ancestry, and can thus be considered as predisposing genes. In addition to their diagnostic value, anti-PLA2R1 antibodies can be used to monitor treatment. Immunization against cationic bovine serum albumin is a cause of early childhood membranous nephropathy. This finding points to a possible role of food and environmental antigens in membranous nephropathy. The newly identified antigen-antibody systems should be considered as molecular signatures challenging the uniform histological definition and having a major impact on patient care in a near future.

Idiopathic membranous nephropathy and nephrotic syndrome: outcome in the era of evidence-based therapy

BACKGROUND

Contemporary studies analysing the long-term outcomes of patients with idiopathic membranous nephropathy and nephrotic syndrome in the era of evidence-based antiproteinuric and immunosuppressive therapies are sparse. Controversy also persists regarding which immunosuppression (IS) regimen to use. In this retrospective cohort study, we aimed to characterize time to partial remission (PR), complete remission (CR), requirement for renal replacement therapy (RRT) or death. We aimed to assess which factors predicted RRT or death and determine the impact of IS on outcome.

METHODS

Ninety-five consecutive adult patients attending two centres between 1997 and 2008 were identified. Baseline demographics and subsequent treatment and outcome were recorded.

RESULTS

Ninety-five percent of patients were prescribed angiotensin-converting enzyme inhibitors and/or angiotensin-receptor blocker (ACEI/ARB) therapy, 78% statin therapy, 70% antiplatelets and 38% IS. The 5-year actuarial rates for PR, CR, RRT and death were 76.4, 24.4, 11.9 and 16.8%, respectively. In patients achieving at least one PR, the 5-year actuarial risk of relapse was 32.8%. Using multivariate survival analysis, achievement of remission was the factor most strongly associated with reduced risk of RRT or death. There was no significant difference in outcomes between patients who did or did not receive IS, although patients receiving IS had more severe disease. Contrary to published findings, 81.8% of patients treated with the Ponticelli regimen (6 months of alternating prednisolone and cyclophosphamide or chlorambucil) suffered significant treatment-related complications compared with 19% of patients prescribed the Cattran regimen (prolonged combined low-dose prednisolone and cyclosporine).

CONCLUSIONS

Using an approach of widespread ACEI/ARB treatment and targeted IS, 76% of patients can expect to have achieved at least one PR by 5 years. Achievement of remission is the factor most strongly associated with reduced risk of RRT and death. Treatment with IS is associated with significant treatment complications.

Proteomics in chronic kidney disease: The issues clinical nephrologists need an answer for

A growing number of patients are recognised to have chronic kidney disease (CKD). However, only a minority will progress to end-stage renal disease requiring dialysis or transplantation. Currently available diagnostic and staging tools frequently fail to identify those at higher risk of progression or death. Furthermore within specific disease entities there are shortcomings in the prediction of the need for therapeutic interventions or the response to different forms of therapy. Kidney and urine proteomic biomarkers are considered as promising diagnostic tools to predict CKD progression early in diabetic nephropathy, facilitating timely and selective intervention that may reduce the related health-care expenditures. However, independent groups have not validated these findings and the technique is not currently available for routine clinical care. Furthermore, there are gaps in our understanding of predictors of progression or need for therapy in non-diabetic CKD. Presumably, a combination of tissue and urine biomarkers will be more informative than individual markers. This review identifies clinical questions in need of an answer, summarises current information on proteomic biomarkers and CKD, and describes the European Kidney and Urine Proteomics initiative that has been launched to carry out a clinical study aimed at identifying urinary proteomic biomarkers distinguishing between fast and slow progressors among patients with biopsy-proven primary glomerulopathies.

Risk HLA-DQA1 and PLA(2)R1 alleles in idiopathic membranous nephropathy

BACKGROUND

Idiopathic membranous nephropathy is a major cause of the nephrotic syndrome in adults, but its etiologic basis is not fully understood. We investigated the genetic basis of biopsy-proven cases of idiopathic membranous nephropathy in a white population.

METHODS

We performed independent genomewide association studies of single-nucleotide polymorphisms (SNPs) in patients with idiopathic membranous nephropathy from three populations of white ancestry (75 French, 146 Dutch, and 335 British patients). The patients were compared with racially matched control subjects; population stratification and quality controls were carried out according to standard criteria. Associations were calculated by means of a chi-square basic allele test; the threshold for significance was adjusted for multiple comparisons (with the Bonferroni method).

RESULTS

In a joint analysis of data from the 556 patients studied (398 men), we identified significant alleles at two genomic loci associated with idiopathic membranous nephropathy. Chromosome 2q24 contains the gene encoding M-type phospholipase A(2) receptor (PLA(2)R1) (SNP rs4664308, P=8.6×10(-29)), previously shown to be the target of an autoimmune response. Chromosome 6p21 contains the gene encoding HLA complex class II HLA-DQ alpha chain 1 (HLA-DQA1) (SNP rs2187668, P=8.0×10(-93)). The association with HLA-DQA1 was significant in all three populations (P=1.8×10(-9), P=5.6×10(-27), and P=5.2×10(-36) in the French, Dutch, and British groups, respectively). The odds ratio for idiopathic membranous nephropathy with homozygosity for both risk alleles was 78.5 (95% confidence interval, 34.6 to 178.2).

CONCLUSIONS

An HLA-DQA1 allele on chromosome 6p21 is most closely associated with idiopathic membranous nephropathy in persons of white ancestry. This allele may facilitate an autoimmune response against targets such as variants of PLA2R1. Our findings suggest a basis for understanding this disease and illuminate how adaptive immunity is regulated by HLA.