The Evidence-Based Approach to Adult-Onset Idiopathic Nephrotic Syndrome

Immunosuppression for adult steroid-dependent or frequently relapsing nephrotic syndrome: A systematic review and meta-analysis

OBJECTIVE

There is limited evidence on which immunosuppressive agents produce the best outcomes for adult patients with steroid-dependent or frequently relapsing nephrotic syndrome (SDNS/FRNS). This review compares the remission rate and adverse effects of various immunosuppressants used.

METHODS

Studies of adult patients with biopsy-proven SDNS/FRNS, administered any immunosuppressive agents and reported complete remission results as one of the clinical outcomes were included. Articles were independently screened by two researchers. ROBINS-I was used for risk of bias assessment. Random-effects model was used for statistical analysis and corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

574 patients across 28 studies were included in the analysis. Patients receiving rituximab have a complete remission rate of 89% (95% CI = 83% to 94%; τ2 = 0.0070; I2 = 62%; overall p < 0.01, low certainty) and adverse event rate of 0.26, cyclosporine (CR 40%; 95% CI = 21% to 59%; τ2 = 0.0205; I2 = 55%; overall p = 0.08, low certainty), tacrolimus (CR 84%; 95% CI = 70% to 98%; τ2 = 0.0060; I2 = 33%; overall p = 0.21, moderate certainty), mycophenolate mofetil (CR 82%; 95% CI = 74% to 90%; τ2 < 0.0001; I2 = 15%; overall p = 0.32, moderate certainty) and cyclophosphamide (CR 79%; 95% CI = 69% to 89%; τ2 = 0; I2 = 0%; overall p = 0.52, moderate certainty).

CONCLUSION

Among the commonly used immunosuppressive agents, only rituximab has a statistically significant effect in achieving complete remission among patients with SDNS/FRNS and has a relatively good safety profile, but this is limited by low quality of evidence with high degree of heterogeneity causing a lack of statistical power.

Use of mycophenolate mofetil in patients with pediatric and adult primary nephrotic syndrome: information from a Japanese hospital claims database

Background

Current treatment for frequently relapsing, steroid-dependent, or steroid-resistant nephrotic syndrome focuses on immunosuppressive therapies. Although the clinical guideline suggests the use of mycophenolate mofetil (MMF), limited information is available on patients with primary nephrotic syndrome who receive off-label treatment with MMF in Japan.

Method

The dose, treatment duration, previous treatment, and characteristics of primary nephrotic syndrome patients receiving MMF were investigated using data from a Japanese hospital claims database (April 2008–September 2021).

Results

Data on 424 primary nephrotic syndrome patients receiving MMF (146 patients < 18 years old; 278 patients ≥ 18 years old) were captured. The most common initial daily doses of MMF capsules (% of patients < 18 and ≥ 18 years old) were 1000 mg (31.9%, 36.8%), 1500 mg (16.0%, 23.8%), and 500 mg (23.6%, 17.3%), and the most common maximum daily doses were 1000 mg (43.8%, 32.9%), 1500 mg (23.6%, 28.9%), and 2000 mg (6.3%, 16.2%). Most patients (97.9%, 99.3%) were treated with a daily dose of 2000 mg or less. Among patients < 18 years old, the younger the patient, the lower the dose. MMF was used for more than 1 year in 30.8% of patients < 18 years old and in 28.8% of patients ≥ 18 years old.

Conclusions

Our study suggested that off-label use of MMF for primary nephrotic syndrome has increased since 2012 in Japan. The dose of MMF used in patients with primary nephrotic syndrome was generally within the approved dose range for lupus nephritis and transplant-related diseases in Japan.

Selective modulator of nuclear receptor PPARγ with reduced adipogenic potential ameliorates experimental nephrotic syndrome

Glomerular disease manifests as nephrotic syndrome (NS) with high proteinuria and comorbidities, and is frequently refractory to standard treatments. We hypothesized that a selective modulator of PPARγ, GQ-16, will provide therapeutic advantage over traditional PPARγ agonists for NS treatment. We demonstrate in a pre-clinical NS model that proteinuria is reduced with pioglitazone to 64%, and robustly with GQ-16 to 81% of nephrosis, comparable to controls. Although both GQ-16 and pioglitazone restore glomerular-Nphs1, hepatic-Pcsk9 and serum-cholesterol, only GQ-16 restores glomerular-Nrf2, and reduces hypoalbuminemia and hypercoagulopathy. GQ-16 and pioglitazone restore common and distinct glomerular gene expression analyzed by RNA-seq and induce insulin sensitizing adipokines to various degrees. Pioglitazone but not GQ-16 induces more lipid accumulation and aP2 in adipocytes and white adipose tissue. We conclude that selective modulation of PPARγ by a partial agonist, GQ-16, is more advantageous than pioglitazone in reducing proteinuria, NS associated comorbidities, and adipogenic side effects of full PPARγ agonists.

Interventions for minimal change disease in adults with nephrotic syndrome

BACKGROUND

Steroids have been used widely since the early 1970s for the treatment of adult-onset minimal change disease (MCD). Recently, newer agents have been used in adult MCD aiming to reduce the risk of adverse effects. The response rates to immunosuppressive agents in adult MCD are more variable than in children. The optimal agent, dose, and duration of treatment for the first episode of nephrotic syndrome, or for disease relapse(s) have not been determined. This is an update of a review first published in 2008.

OBJECTIVES

We aimed to 1) evaluate the benefits and harms of different agents, including both immunosuppressive and non-immunosuppressive agents, in adults with MCD causing the nephrotic syndrome; and 2) evaluate the efficacy of interventions on 'time-to-remission' of nephrotic syndrome, in adults with MCD causing the nephrotic syndrome.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 21 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are 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) and quasi-RCTs of any intervention for MCD with nephrotic syndrome in adults over 18 years were included. Studies comparing different types, routes, frequencies, and duration of immunosuppressive agents and non-immunosuppressive agents were assessed.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model and results were expressed as a risk ratio (RR) for dichotomous outcomes, or mean difference (MD) for continuous data with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Fifteen RCTs (769 randomised participants) were identified; four studies evaluated different prednisolone regimens, eight studies evaluated the calcineurin inhibitors (CNIs) (tacrolimus or cyclosporin), two studies evaluated enteric-coated mycophenolate sodium (EC-MPS) and one study evaluated levamisole. In all but two studies of non-corticosteroid agents, reduced-dose prednisolone was given with the treatment agent and the comparator was high-dose prednisolone. In the risk of bias assessment, 11 and seven studies were at low risk of bias for sequence generation and allocation concealment, respectively. No studies were at low risk of performance bias and eight studies were at low risk of detection bias. Thirteen, 10 and six studies were at low risk of attrition bias, reporting bias and other bias, respectively. Compared with no specific treatment, it is uncertain whether prednisolone increases the number with complete remission (1 study, 28 participants: RR 1.44, 95% CI 0.95 to 2.19), complete or partial remission (1 study, 28 participants: RR 1.38, 95% CI 0.98 to 1.95), subsequent relapse (1 study, 28 participants: RR 0.75, 95% CI 0.48 to 1.17), or reduces the adverse effects because the certainty of the evidence is very low. Compared with oral prednisolone alone, it is uncertain whether intravenous methylprednisolone and prednisolone increase the number with complete remission (2 studies, 35 participants: RR 1.76, 95% CI 0.17 to 18.32; I² = 90%), relapse (two studies, 19 participants. RR 1.18, 95% CI 0.65 to 2.15; I² = 0%) or adverse events because the certainty of the evidence is very low. Compared with prednisolone alone, CNIs with reduced-dose prednisolone or without prednisolone probably make little or no difference to the number achieving complete remission (8 studies; 492 participants: RR 0.99, 95% CI 0.93 to 1.05; I² = 0%), complete or partial remission (4 studies, 269 participants: RR 1.01, 95% CI 0.96 to 1.05; I² = 0%), or relapse (7 studies; 422 participants: RR 0.73, 95% CI 0.51 to 1.03; I² = 0%) (moderate certainty evidence), may reduce the risk of obesity or Cushing's Syndrome (5 studies; 388 participants: RR 0.11, 95% CI 0.02 to 0.59; I² = 45%) and the risk of acne (4 studies; 270 participants: RR 0.15, 95% CI 0.03 to 0.67; I² = 0%) (low certainty evidence); and had uncertain effects on diabetes or hyperglycaemia, hypertension, and acute kidney injury (AKI) (low certainty evidence). Compared with prednisolone alone, EC-MPS with reduced-dose prednisolone probably make little or no difference to the number undergoing complete remission at 4 weeks (1 study, 114 participants: RR 1.12, 95% CI 0.84 to 1.50), and at 24 weeks probably make little or no difference to the number undergoing complete remission (2 studies, 134 participants: RR 1.12, 95% CI 0.84 to 1.38; I² = 0%) (moderate certainty evidence), complete or partial remission (2 studies 134 participants: RR 0.92, 95% CI 0.75 to 1.12; I² = 0%), relapse (2 studies, 83 participants: RR 0.50, 95% CI 0.07 to 3.74; I² = 56%) (low certainty evidence); or to the adverse events of new-onset glucose intolerance, death, or AKI (low certainty evidence). One study (24 participants) compared levamisole and prednisolone with prednisolone in patients with relapsing disease. The authors identified no differences in mean relapse rate or adverse effects but no standard deviations were provided.

AUTHORS' CONCLUSIONS

This updated review has identified evidence for the efficacy and adverse effects of CNIs and EC-MPS with or without reduced-dose prednisolone compared with prednisolone alone for the induction of remission in adults with MCD and nephrotic syndrome with some reductions in steroid-associated adverse events. RCT data on the efficacy and adverse effects of rituximab in adults with MCD are awaited. Further, adequately powered RCTs are required to determine the relative efficacies of CNIs and EC-MPS and to evaluate these medications in patients with relapsing or steroid-resistant disease.

Minimal Change Disease After Elective Surgical Abortion: A Case Report

Patient: Female, 21-year-old

Final Diagnosis: Minimal change disease

Symptoms: Anasarca • proteinuria

Medication: —

Clinical Procedure: Abortion

Specialty: Nephrology

Hypomethylation of NLRP3 gene promoter discriminates glucocorticoid-resistant from glucocorticoid-sensitive idiopathic nephrotic syndrome patients

Abstract

To assess whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid (GC)‐resistant from GC‐sensitive idiopathic nephrotic syndrome (INS), patients with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), we measured the methylation level of NLRP3 promoter in DNA from peripheral blood cells of 10 adult patients with GC‐resistant FSGS already in hemodialysis and 18 patients with GC‐sensitive INS (13 MCD/5 FSGS) and in 21 pediatric patients with INS with MCD/FSGS before starting any treatment. Association of NLRP3 inflammasome with GC resistance was recapitulated in vitro in monocytic cell lines (THP‐1 and U937). In both adults and pediatric patients, NLRP3 promoter methylation was significantly reduced in GC‐resistant compared with GC‐sensitive patients. Indeed, NLRP3 methylation distinguished GC‐resistant and GC‐sensitive patients (area under the receiver operating characteristic curve [AUROC] 86.7% in adults, p = 0.00019, and 73.5% in children, p = 0.00097). NLRP3 knock‐down augmented sensitivity to GCs in THP‐1 cells, whereas NLRP3 inflammasome activation lowered GC receptor concentration, increasing GC resistance in U937 cells. Our results uncovered a new biological mechanism by which patients with INS may acquire GC resistance, that could be used in future as a novel noninvasive diagnostic tool.

Plasma Cytokine Profiling to Predict Steroid Resistance in Pediatric Nephrotic Syndrome

Introduction

Glucocorticoids (GCs) are the primary treatment for nephrotic syndrome (NS), although ∼10% to 20% of children develop steroid-resistant NS (SRNS). Unfortunately, there are no validated biomarkers able to predict SRNS at initial disease presentation. We hypothesized that a plasma cytokine panel could predict SRNS at disease presentation, and identify potential pathways regulating SRNS pathogenesis.

Methods

Paired plasma samples were collected from 26 children with steroid-sensitive NS (SSNS) and 14 with SRNS at NS presentation and after ∼7 weeks of GC therapy, when SSNS versus SRNS was clinically determined. Plasma cytokine profiling was performed with a panel of 27 cytokines.

Results

We identified 13 cytokines significantly different in Pretreatment SSNS versus SRNS samples. Statistical modeling identified a cytokine panel (interleukin [IL]-7, IL-9, monocyte chemoattractant protein–1 [MCP-1]) able to discriminate between SSNS and SRNS at disease presentation (receiver operating characteristic [ROC] value = 0.846; sensitivity = 0.643; specificity = 0.846). Furthermore, GC treatment resulted in significant decreases in plasma interferon-γ (IFN-γ), tumor necrosis factor–α (TNF-α), IL-7, IL-13, and IL-5 in both SSNS and SRNS patients.

Conclusions

These studies suggest that initial GC treatment of NS reduces the plasma cytokines secreted by both CD4⁺ T_H1 cells and T_H2 cells, as well as CD8⁺ T cells. Importantly, a panel of 3 cytokines (IL-7, IL-9, and MCP-1) was able to predict SRNS prior to GC treatment at disease presentation. Although these findings will benefit from validation in a larger cohort, the ability to identify SRNS at disease presentation could greatly benefit patients by enabling both avoidance of unnecessary GC-induced toxicity and earlier transition to more effective alternative treatments.

Comparison of the Efficacy and Safety of Tacrolimus and Low-Dose Corticosteroid with High-Dose Corticosteroid for Minimal Change Nephrotic Syndrome in Adults

BACKGROUND

Tacrolimus is used as a steroid-sparing immunosuppressant in adults with minimal change nephrotic syndrome. However, combined treatment with tacrolimus and low-dose steroid has not been compared with high-dose steroid for induction of clinical remission in a large-scale randomized study.

METHODS

In this 24-week open-label noninferiority study, we randomized 144 adults with minimal change nephrotic syndrome to receive 0.05 mg/kg twice-daily tacrolimus plus once-daily 0.5 mg/kg prednisolone, or once-daily 1 mg/kg prednisolone alone, for up to 8 weeks or until achieving complete remission. Two weeks after complete remission, we tapered the steroid to a maintenance dose of 5-7.5 mg/d in both groups until 24 weeks after study drug initiation. The primary end point was complete remission within 8 weeks (urine protein: creatinine ratio <0.2 g/g). Secondary end points included time until remission and relapse rates (proteinuria and urine protein: creatinine ratio >3.0 g/g) after complete remission to within 24 weeks of study drug initiation.

RESULTS

Complete remission within 8 weeks occurred in 53 of 67 patients (79.1%) receiving tacrolimus and low-dose steroid and 53 of 69 patients (76.8%) receiving high-dose steroid; this difference demonstrated noninferiority, with an upper confidence limit below the predefined threshold (20%) in both intent-to-treat (11.6%) and per-protocol (17.0%) analyses. Groups did not significantly differ in time until remission. Significantly fewer patients relapsed on maintenance tacrolimus (3-8 ng/ml) plus tapered steroid versus tapered steroid alone (5.7% versus 22.6%, respectively; P=0.01). There were no clinically relevant safety differences.

CONCLUSIONS

Combined tacrolimus and low-dose steroid was noninferior to high-dose steroid for complete remission induction in adults with minimal change nephrotic syndrome. Relapse rates were significantly lower with maintenance tacrolimus and steroid compared with steroid alone. No clinically-relevant differences in safety findings were observed.

Nuclear receptors in podocyte biology and glomerular disease

Nuclear receptors have a broad spectrum of biological functions in normal physiology and in the pathology of various diseases, including glomerular disease. The primary therapies for many glomerular diseases are glucocorticoids, which exert their immunosuppressive and direct podocyte protective effects via the glucocorticoid receptor (GR). As glucocorticoids are associated with important adverse effects and a substantial proportion of patients show resistance to these therapies, the beneficial effects of selective GR modulators are now being explored. Peroxisome proliferator-activated receptor-γ (PPARγ) agonism using thiazolidinediones has potent podocyte cytoprotective and nephroprotective effects. Repurposing of thiazolidinediones or identification of novel PPARγ modulators are potential strategies to treat non-diabetic glomerular disease. Retinoic acid receptor-α is the key mediator of the renal protective effects of retinoic acid, and repair of the endogenous retinoic acid pathway offers another potential therapeutic strategy for glomerular disease. Vitamin D receptor, oestrogen receptor and mineralocorticoid receptor modulators regulate podocyte injury in experimental models. Further studies are needed to better understand the mechanisms of these nuclear receptors, evaluate their synergistic pathways and identify their novel modulators. Here, we focus on the role of nuclear receptors in podocyte biology and non-diabetic glomerular disease.

Predicting and Defining Steroid Resistance in Pediatric Nephrotic Syndrome Using Plasma Proteomics

INTRODUCTION

Nephrotic syndrome (NS) is a characterized by massive proteinuria, edema, hypoalbuminemia, and dyslipidemia. Glucocorticoids (GCs), the primary therapy for >60 years, are ineffective in approximately 50% of adults and approximately 20% of children. Unfortunately, there are no validated biomarkers able to predict steroid-resistant NS (SRNS) or to define the pathways regulating SRNS.

METHODS

We performed proteomic analyses on paired pediatric NS patient plasma samples obtained both at disease presentation before glucocorticoid initiation and after approximately 7 weeks of GC therapy to identify candidate biomarkers able to either predict steroid resistance before treatment or define critical molecular pathways/targets regulating steroid resistance.

RESULTS

Proteomic analyses of 15 paired NS patient samples identified 215 prevalent proteins, including 13 candidate biomarkers that predicted SRNS before GC treatment, and 66 candidate biomarkers that mechanistically differentiated steroid-sensitive NS (SSNS) from SRNS. Ingenuity Pathway Analyses and protein networking pathways approaches further identified proteins and pathways associated with SRNS. Validation using 37 NS patient samples (24 SSNS/13 SRNS) confirmed vitamin D binding protein (VDB) and APOL1 as strong predictive candidate biomarkers for SRNS, and VDB, hemopexin (HPX), adiponectin (ADIPOQ), sex hormone-binding globulin (SHBG), and APOL1 as strong candidate biomarkers to mechanistically distinguish SRNS from SSNS. Logistic regression analysis identified a candidate biomarker panel (VDB, ADIPOQ, and matrix metalloproteinase 2 [MMP-2]) with significant ability to predict SRNS at disease presentation (P = 0.003; area under the receiver operating characteristic curve = 0.78).

CONCLUSION

Plasma proteomic analyses and immunoblotting of serial samples in childhood NS identified a candidate biomarker panel able to predict SRNS at disease presentation, as well as candidate molecular targets/pathways associated with clinical steroid resistance.

Diagnostic Utility of Exome Sequencing for Kidney Disease

BACKGROUND

Exome sequencing is emerging as a first-line diagnostic method in some clinical disciplines, but its usefulness has yet to be examined for most constitutional disorders in adults, including chronic kidney disease, which affects more than 1 in 10 persons globally.

METHODS

We conducted exome sequencing and diagnostic analysis in two cohorts totaling 3315 patients with chronic kidney disease. We assessed the diagnostic yield and, among the patients for whom detailed clinical data were available, the clinical implications of diagnostic and other medically relevant findings.

RESULTS

In all, 3037 patients (91.6%) were over 21 years of age, and 1179 (35.6%) were of self-identified non-European ancestry. We detected diagnostic variants in 307 of the 3315 patients (9.3%), encompassing 66 different monogenic disorders. Of the disorders detected, 39 (59%) were found in only a single patient. Diagnostic variants were detected across all clinically defined categories, including congenital or cystic renal disease (127 of 531 patients [23.9%]) and nephropathy of unknown origin (48 of 281 patients [17.1%]). Of the 2187 patients assessed, 34 (1.6%) had genetic findings for medically actionable disorders that, although unrelated to their nephropathy, would also lead to subspecialty referral and inform renal management.

CONCLUSIONS

Exome sequencing in a combined cohort of more than 3000 patients with chronic kidney disease yielded a genetic diagnosis in just under 10% of cases. (Funded by the National Institutes of Health and others.).

Association of Exposure to Fine-Particulate Air Pollution and Acidic Gases with Incidence of Nephrotic Syndrome

Background: Air pollution has been associated with autoimmune diseases. Nephrotic syndrome is a clinical manifestation of immune-mediated glomerulopathy. However, the association between nephrotic syndrome and air pollution constituents remains unknown. We conducted this nationwide retrospective study to investigate the association between PM_2.5 and nephrotic syndrome. Methods: We used the Longitudinal Health Insurance Database (LHID) and the Taiwan Air Quality-Monitoring Database (TAQMD). We combined and stratified the LHID and the TAQMD data by residential areas of insurants linked to nearby air quality-monitoring stations. Air pollutant concentrations were grouped into four levels based on quartile. Univariable and multivariable Cox proportional hazard regression models were applied. Findings: Relative to Q1-level SO₂, subjects exposed to the Q4 level were associated with a 2.00-fold higher risk of nephrotic syndrome (adjusted HR = 2.00, 95% CI = 1.66⁻2.41). In NOx, relative to Q1 NOx concentrations, the adjusted HRs of nephrotic syndrome risk were 1.53 (95% CI = 1.23⁻1.91), 1.30 (95% CI = 1.03⁻1.65), and 2.08 (95% CI = 1.69⁻2.56) for Q2, Q3, and Q4 levels, respectively. The results revealed an increasing trend for nephrotic syndrome risk correlating with increasing levels of NO, NO₂, and PM_2.5 concentrations. Interpretation: High concentrations of PM_2.5, NO, NO₂, and SO₂ are associated with increased risk of nephrotic syndrome.

Spontaneous remission of adult-onset minimal change nephrotic syndrome associated with influenza B infection: a case report

Background

While the majority of adult-onset minimal change nephrotic syndrome (MCNS) is a primary or an idiopathic form of disease, it can also occur as a secondary form. Reports on the spontaneous remission of MCNS are rare since the condition is typically treated with corticosteroids. We herein describe the spontaneous remission of adult-onset MCNS in a patient who developed nephrotic syndrome after type B influenza infection.

Case presentation

A 50-year-old woman experienced fever, cough, malaise, and low back pain, which had persisted for 6 days before she presented to our hospital, and edema of the face and limbs, which had persisted for 5 days before her presentation. She was diagnosed with type B influenza infection and later exhibited an exacerbation of facial edema, decreased urine output, and a high level of proteinuria. She was referred to our department after the diagnosis of nephrotic syndrome. On admission, her proteinuria level was 20.88 g/gCr and her selectivity index value was 0.13. The examination of a kidney biopsy specimen obtained on the fourth day of hospitalization under a light microscope revealed minor abnormalities. An immunofluorescence showed only nonspecific granular IgM deposits in the mesangium. Electron microscopy showed extensive foot process effacement without any immune complex deposits. Based on these findings, the patient was diagnosed with MCNS. After admission, the proteinuria decreased to 0.06 g/gCr with rest and sodium restriction (6 g/day) alone; a complete remission from nephrotic syndrome was observed at approximately 2 weeks after the onset of symptoms. There have been no signs of recurrence of nephrotic syndrome in the one years since.

Conclusion

We experienced a rare case in which spontaneous remission of MCNS occurred within a short period of 2 weeks after influenza B infection. When patients present with nephrotic syndrome after an infection, it is necessary to consider MCNS in the differential diagnosis, which also includes post-infectious glomerulonephritis and the acute exacerbation of IgA nephropathy.

Regional variations in immunosuppressive therapy in patients with primary nephrotic syndrome: the Japan nephrotic syndrome cohort study

BACKGROUND

The lack of high-quality clinical evidences hindered broad consensus on optimal therapies for primary nephrotic syndromes. The aim of the present study was to compare prevalence of immunosuppressive drug use in patients with primary nephrotic syndrome across 6 regions in Japan.

METHODS

Between 2009 and 2010, 380 patients with primary nephrotic syndrome in 56 hospitals were enrolled in a prospective cohort study [Japan Nephrotic Syndrome Cohort Study (JNSCS)], including 141, 151, and 38 adult patients with minimal change disease (MCD), membranous nephropathy (MN), and focal segmental glomerulosclerosis (FSGS), respectively. Their clinical characteristics were compared with those of patients registered in a large nationwide registry of kidney biopsies [Japan Renal Biopsy Registry (J-RBR)]. The regional prevalence of use of each immunosuppressive drug was assessed among adult MCD, MN, and FSGS patients who underwent immunosuppressive therapy in the JNSCS (n = 139, 127, and 34, respectively). Predictors of its use were identified using multivariable-adjusted logistic regression models.

RESULTS

The clinical characteristics of JNSCS patients were comparable to those of J-RBR patients, suggesting that the JNSCS included the representatives in the J-RBR. The secondary major immunosuppressive drugs were intravenous methylprednisolone [n = 33 (24.6%), 24 (19.7%), and 9 (28.1%) in MCD, MN, and FSGS, respectively] and cyclosporine [n = 25 (18.7%), 62 (50.8%), and 16 (50.0%), respectively]. The region was identified as a significant predictor of use of intravenous methylprednisolone in MCD and MN patients.

CONCLUSION

Use of intravenous methylprednisolone for MCD and MN differed geographically in Japan. Its efficacy should be further evaluated in a well-designed trial.

Efficacy of mycophenolate treatment in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome

BACKGROUND

This study assessed the efficacy of therapy with mycophenolate (MF) and reduced doses of steroids in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome (SD/FR-INS).

METHODS

Twenty-nine nephrotic patients (including 16 males and 13 females; mean age: 40 years, range: 18-74) were treated. Starting doses of MF were 2000 mg/day for mofetil MF (1500 mg/day in one patient) or 1440 mg/day for sodium MF. The initial prednisone (PDN) dose was 10 mg/day in 14 patients, 5 mg/day in two patients and no steroids in one patient. In the remaining 12 patients, moderate initial doses of PDN were administered (mean: 23.7 mg/day, range: 15-40), tapering to 10 mg/day after 1 month.

RESULTS

Nephrotic syndrome remission was achieved in 27/29 cases (93.1%) (25 complete, 2 partial). Two patients showed resistance to the prescribed schedule. The first cycle of MF therapy was concluded in 20 patients after a mean (range) of 16.9 months (12-49). Maintenance of remission was observed in 11 of these 20 cases (55%) after a mean follow-up of 32.8 months (12-108). In nine patients with nephrotic syndrome relapse after tapering of MF (MF dependency), the same MF-PDN schedule was restarted, leading again to remission in all nine. The remaining seven MF-sensitive patients are still receiving their first therapeutic cycle. To date, the mean time under therapy in the 27 MF-sensitive patients is 38 months (4-216). Regarding complications, only minor digestive disorders and a slight decrease in blood haemoglobin levels were observed in a few patients.

CONCLUSIONS

MF plus reduced doses of PDN is an effective and well-tolerated therapy for adult SD/FR-INS. Though MF dependence is observed, its low toxicity could allow long periods of therapy if it is required to maintain nephrotic syndrome remission.

Minimal Change Disease

Minimal change disease (MCD) is a major cause of idiopathic nephrotic syndrome (NS), characterized by intense proteinuria leading to edema and intravascular volume depletion. In adults, it accounts for approximately 15% of patients with idiopathic NS, reaching a much higher percentage at younger ages, up to 70%-90% in children >1 year of age. In the pediatric setting, a renal biopsy is usually not performed if presentation is typical and the patient responds to therapy with oral prednisone at conventional doses. Therefore, in this setting steroid-sensitive NS can be considered synonymous with MCD. The pathologic hallmark of disease is absence of visible alterations by light microscopy and effacement of foot processes by electron microscopy. Although the cause is unknown and it is likely that different subgroups of disease recognize a different pathogenesis, immunologic dysregulation and modifications of the podocyte are thought to synergize in altering the integrity of the glomerular basement membrane and therefore determining proteinuria. The mainstay of therapy is prednisone, but steroid-sensitive forms frequently relapse and this leads to a percentage of patients requiring second-line steroid-sparing immunosuppression. The outcome is variable, but forms of MCD that respond to steroids usually do not lead to chronic renal damage, whereas forms that are unresponsive to steroids may subsequently reveal themselves as FSGS. However, in a substantial number of patients the disease is recurrent and requires long-term immunosuppression, with significant morbidity because of side effects. Recent therapeutic advances, such as the use of anti-CD20 antibodies, have provided long-term remission off-therapy and suggest new hypotheses for disease pathogenesis.