Retrospective Cross-Sectional Study Reviewing the Effectiveness of Mycophenolate Mofetil on Saudi Children With Nephrotic Syndrome

Background Idiopathic nephrotic syndrome (INS) is the most common form of nephrotic syndrome (NS) in children. It is often associated with minimal change disease (MCD). Corticosteroid therapy is the initial treatment, but many patients experience relapses, leading to steroid-dependent nephrotic syndrome (SDNS) or frequently relapsing steroid-sensitive nephrotic syndrome (FR-SSNS). To avoid prolonged steroid use, mycophenolate mofetil (MMF) is used as an immunosuppressive alternative. MMF is safe and effective for treating SDNS and FR-SSNS in children, with studies showing reduced relapse rates. The current study aims to evaluate MMF's effectiveness and safety in Saudi children with NS and identify factors that affect its efficacy. Methods A retrospective cross-sectional study was conducted at King Abdullah Specialized Children's Hospital (KASCH) in Riyadh, Saudi Arabia. The study included children aged one to 14 years diagnosed with NS who received MMF therapy. Data were collected from medical records from 2000 to 2020. Ethical considerations were followed, and statistical analysis was performed using IBM SPSS Statistics for Windows, version 25 (released 2017; IBM Corp., Armonk, New York, United States). Baseline characteristics and responsiveness to MMF were examined. Results In our study, 45 participants (25 males, 20 females) with NS were treated with MMF. Most participants were steroid-dependent (84.44%) and had frequent relapses. MMF was effective in 84.4% of cases, with a significant reduction in relapse; the mean number of relapses decreased from 3.5 before MMF to 1.6 after MMF (p-value = 0.00002). Moreover, 40% of the participants were completely free of relapse after the introduction of MMF. The average duration of the MMF therapy was 45 months. Post-MMF side effects were rare but documented. Gastrointestinal symptoms were extremely rare. Elevated liver enzyme levels were reported in 8.88% (four cases) of the participants. Leukopenia, a more common adverse effect, was reported in 26.66% of cases during the MMF therapy. The average daily dose of steroid was reduced from 12.5 mg/day pre MMF to 2 mg/day post MMF with a p-value of 0.00229. Conclusion Our study evaluated the use of MMF in 45 participants with NS. We found that MMF was effective in 84.4% of cases, leading to a significant reduction in the number of relapses. Post-MMF side effects were relatively rare, except for leukopenia that was reported in 26.66%. In addition, the average rate of reduction of steroid exposure before and after MMF was significant. These findings suggest that MMF is a promising treatment option for children with NS and an alternative therapy to long-term steroid use, due to its safety and effectiveness, although close monitoring for potential side effects is essential.

Incidence of relapse and frequently relapsing/steroid-dependent nephrotic syndrome in Chinese children with steroid-sensitive nephrotic syndrome: A cohort study

AIM

This study aimed to investigate the incidence of relapse and FR/SDNS in Chinese children with SSNS and to develop clinical prediction models for relapse and FR/SDNS.

METHODS

This retrospective cohort study involved 339 newly onset SSNS patients between 2006 and 2016. The incidence of relapse and FR/SDNS were estimated using the Kaplan-Meier method. Prediction models were constructed based on Cox proportional-hazards regression.

RESULTS

The median follow-up time was 8.7 years. The cumulative incidence of relapse at 1-, 2-, and 5-year was 51.0%, 62.5%, and 66.6%. The cumulative incidence of FR/SDNS at 1-, 2-, and 5-year was 18.4%, 29.0%, and 32.9%. The final prediction model for first relapse included four variables (serum albumin, triglycerides, IgM, and time to first remission). The model's discriminative ability was low (Harrell's C index = 0.62). The final prediction model for FR/SDNS included four variables (serum albumin, lipoprotein(a), time to first remission, and time to first relapse). The discrimination and calibration of the prediction model for FR/SDNS were acceptable (Harrell's C index = 0.73, Brier score at 1- and 2-year were 0.11 and 0.17).

CONCLUSION

The first relapse and FR/SDNS mainly occurred in the first 2 years after initial SSNS onset. The prediction model for relapse developed using common clinical parameters performed poorly, while the prediction model for FR/SDNS might be useful.

Effectiveness of a Low Dose Prednisolone Regimen for Treatment of Relapses in Children with Steroid Sensitive Nephrotic Syndrome

Introduction

There may be a role of reducing the total steroid doses for the treatment of relapses of nephrotic syndrome in children with milder and more stable disease. The primary objective of this study was to compare the effectiveness of a low-dose prednisolone regimen with standard therapy for the treatment of relapses in steroid-sensitive nephrotic syndrome (SSNS) at the end of treatment, the secondary objectives being time to remission and sustained remission after 3 months.

Methods

This randomized controlled trial included a total of 40 children (20 in each group) with SSNS (presently infrequently relapsing course) and with a relapse. Both groups received prednisolone at a dose of 2 mg/kg/day until remission; subsequently, the patients in the study group received 1 mg/kg, and the control group participants received 1.5 mg/kg prednisolone on alternate days for 4 weeks. The patients were followed up till 3 months after stopping the therapy.

Results

The median (IQR) age of children enrolled was 7.5 (range: 5-9.65) years, and the age at onset of nephrotic syndrome was 4 (range: 2.3-5.5) years. The median time to achieve remission was 9 days (comparable in low dose vs. standard therapy group; P = 0.14). All patients were in remission at the end of therapy; 85% of patients were in the low-dose group and 90% in the standard therapy group after 1 month (P = 0.32). At the end of 3 months, 60% continued to be in remission in the low-dose group and 65% with standard therapy (P = 0.37). Hazard ratios for relapse at the end of 1, 2, and 3 months were 1.05, 1.08, and 1.13, respectively. Patients who were infrequently relapsing (79%) from the onset of nephrotic syndrome had higher remission rates at the end of 3 months (80% in the low-dose group vs. 76.9% in the standard therapy group). Hazard ratios for relapse in these patients at the end of 1, 2, and 3 months were 1.01, 1.03, and 1.08, respectively.

Conclusions

Lower doses of prednisolone can be used for the treatment of relapse of steroid sensitive nephrotic syndrome, with an infrequently relapsing course.

Evaluation of Immune and Vaccine Competence in Steroid-Sensitive Nephrotic Syndrome Pediatric Patients

Idiopathic nephrotic syndrome is a childhood renal disease characterized by a damage of the glomerular filtration barrier leading to an intense leakage of proteins into the urine. This severe proteinuria causes a transient but strong reduction of serum IgG. Therefore, evaluation of vaccine competence by measuring serum levels of protective antibodies can be misleading in nephrotic syndrome, especially during the active phase of disease. To overcome this issue, in parallel to measuring serum antigen-specific IgG, we quantified by ELISPOT the number of antigen-specific memory B cells induced by previous immunization with tetanus and hepatitis B virus (HBV) in 11 steroid-sensitive nephrotic syndrome (SSNS) pediatric patients at onset before any immunosuppressive treatment (mean age 5.1±0.9 years). Five age-matched children with non-immunomediated nephro-urologic disorders were also enrolled as controls (mean age 6.9±2.3 years). Low total serum IgG levels (<520 mg/dl) were found in all the analyzed SSNS patients. In parallel, median levels of anti-tetanus and anti-HBV IgG were significantly reduced compared to controls [0.05 (0.03–0.16) vs. 0.45 (0.29–3.10) IU/ml and 0.0 (0.0–0.5) vs. 30.3 (5.5–400.8) mIU/ml, respectively; p = 0.02 for both], with serum IgG titers below protective threshold in 7/11 SSNS patients for tetanus and in 9/11 SSNS patients for HBV. In contrast, all SSNS patients had a competent B-cell response, showing an amount of total IgG-secreting B cells >1,000 counts/10⁶ stimulated cells. The amount of anti-tetanus and anti-HBV IgG-secreting B cells was also comparable to that of controls (p = 0.24, p = 0.32, respectively), with a frequency of memory anti-tetanus and anti-HBV IgG secreting B cells >0.1% of total IgG secreting B cells. In conclusion, SSNS children at disease onset pre-immunosuppressive therapy showed a competent immune and vaccine response against tetanus and HBV, which can be correctly evaluated by quantification of antigen-specific memory B cells rather than by measuring serum IgG levels. This approach allows early identification of the impairment of immune and vaccine competence, which may derive from protracted use of different immunosuppressive drugs during disease course.

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.

B Lymphocyte Subsets in Children With Steroid-Sensitive Nephrotic Syndrome: A Longitudinal Study

Background: B-cell subsets may be involved in the pathogenesis of childhood steroid-sensitive nephrotic syndrome (SSNS). Horizontal control studies have shown that homeostasis of B-cell subsets changes at different stages of the SSNS. However, there is a lack of longitudinal studies that have investigated dynamic changes in B cell subpopulations. Methods: Blood samples were collected at the following time points from 15 children with SSNS treated at our hospital: before administration of steroid and after 3 days, 1 week, and 3, 6, 9, and 12 months. The proportions of circulating total B cells (CD19⁺), transitional B cells (CD19⁺CD24^highCD38^high), mature B cells (CD19⁺CD24^lowCD38^intermediate), and memory B cells (CD19⁺CD24^highCD38^-) were monitored by flow cytometry. Results: The proportion of CD19+ B cells before steroid administration was significantly higher than that observed at any other time point or in the healthy control (HC) group (p < 0.001). However, this proportion was significantly lower than that in the HC group at 12 months (p = 0.031). Transitional B cells before (%BL 9.5 ± 4.4) and 3 days after steroid administration (%BL 10.6 ± 5.1) were significantly higher than at any other time point or in the HC group (p < 0.001). Although these cells declined after the 3rd day the percentage was still significantly lower than that of the HC group at 12 months (p = 0.029). Memory B cells increased gradually after steroid administration and decreased to the normal range after 9 months. Conclusions: B cell subpopulations show dynamic changes in children with SSNS, suggesting that they are involved in the pathogenesis of the disorder. Further studies are required to determine whether this change can guide individualized treatment.

Novel TBC1D8B Variant in a 6-Month-Old Boy With Steroid-Sensitive Nephrotic Syndrome: A Case Report

A structural abnormality or dysfunction of podocytes is the major cause of nephrotic syndrome (NS). The TBC1D8B protein interacts with nephrin, a podocyte slit diaphragm protein, regulates vesicle transport, and functions in the pathogenesis of NS. We report a novel potentially pathogenic variant in the TBC1D8B gene in a 6-month-old boy with NS. A 6-month-old boy was admitted to the hospital because of edema and fever. Our systematic examination led to a diagnosis of NS. Because of the early age of onset, we performed trio whole-exome sequencing of him and his parents. The results showed a new potentially pathogenic variant in the TBC1D8B gene on the X chromosome, c.2717A>G (p.His906Arg). After routine glucocorticoid therapy, his urine protein turned negative, indicating steroid-sensitive NS. The new TBC1D8B variant identified here, c.2717A>G (p.His906Arg), may be associated with early-onset NS in children. Although NS due to pathogenic variants in this gene is more commonly steroid-resistant, our patient had steroid-sensitive NS.

Initial treatment of steroid-sensitive idiopathic nephrotic syndrome in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial (INTENT study)

INTRODUCTION

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood with an incidence of 1.8 cases per 100 000 children in Germany. The treatment of the first episode implies two aspects: induction of remission and sustainment of remission. The recent Kidney Disease Improving Global Outcomes, American Academy of Pediatrics and German guidelines for the initial treatment of the first episode of a nephrotic syndrome recommend a 12-week course of prednisone. Despite being effective, this treatment is associated with pronounced glucocorticoid-associated toxicity due to high-dose prednisone administration over a prolonged period of time. The aim of the INTENT study (Initial treatment of steroid-sensitive idiopathic nephrotic syndrom in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial) is to show that an alternative treatment regimen with mycophenolic acid is not inferior regarding sustainment of remission, but with lower toxicity compared with treatment with glucocorticoids only.

METHODS AND DESIGN

The study is designed as an open, randomised, controlled, multicentre trial. 340 children with a first episode of steroid-sensitive nephrotic syndrome and who achieved remission by a standard prednisone regimen will be enrolled in the trial and randomised to one of two treatment arms. The standard care group will be treated with prednisone for a total of 12 weeks; in the experimental group the treatment is switched to mycophenolate mofetil, also for a total of 12 weeks in treatment duration. The primary endpoint is the occurrence of a treated relapse within 24 months after completion of initial treatment.

ETHICS AND DISSEMINATION

Ethics approval for this trial was granted by the ethics committee of the Medical Faculty of the University of Heidelberg (AFmu-554/2014). The study results will be published in accordance with the Consolidated Standards of Reporting Trials statement and the Standard Protocol Items: Recommendations for Interventional Trials guidelines. Our findings will be submitted to major international paediatric nephrology and general paediatric conferences and submitted for publication in a peer-reviewed, open-access journal.

TRIAL REGISTRATION NUMBER

DRKS0006547; EudraCT2014-001991-76; Pre-result.

DATE OF REGISTRATION

30 October 2014; 24 February 2017.

Acute kidney injury in children with nephrotic syndrome: a single-center study

Background

Children with nephrotic syndrome (NS) are at risk for the development of acute kidney injury (AKI) through a variety of mechanisms.The frequency of NS hospitalizations complicated by AKI has almost doubled in the last decade. Children with AKI have longer hospital length of stay and increased need for intensive care unit admission. The main objectives of this study were to determine the incidence, clinical characteristics, risk factors and short-term outcome of AKI in children hospitalized with NS.

Methods

In this retrospective study, 355 children ≤18 years of age with a clinical diagnosis of NS admitted in the Department of Nephrology, Gauhati Medical College and Hospital from January 2012 to December 2015 were reviewed.

Results

The incidence of AKI in children with NS was found to be 23.66%, 11.24%, 7.95% and 4.48% of children entered Pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease (pRIFLE) Stages R, I and F, respectively. Infection {odds ratio [OR] 2.53 [95% confidence interval (CI) 1.52–4.22]} and nephrotoxic medication exposure [OR 7.8 (95% CI 4.06–15.01)] were common factors associated with AKI. Children with steroid-dependent NS (SDNS) and steroid-resistant NS (SRNS) were more likely to develop AKI compared with children with steroid-sensitive NS (SSNS). The mean time to recovery for groups pRIFLE Stages R, I and F were 15 ± 2 , 22 ± 3 and 28 ± 5 days, respectively. Children with NS who were hypertensive, had higher urinary protein excretion and low serum albumin were more prone to develop AKI.

Conclusions

AKI is not uncommon in children with NS. Infection and exposure to nephrotoxic drugs are common factors associated with AKI. AKI is more frequent in SDNS and SRNS compared with SSNS. The mean time to recovery is prolonged with more severe AKI.

Glomerular Filtration Rate Trends During Follow-up in Children With Steroid-Sensitive Nephrotic Syndrome

BACKGROUND

Overall prognosis of children with steroid-sensitive nephrotic syndrome (SSNS) is regarded as generally favorable. However, only a few recent studies have evaluated changes in kidney function and blood pressure over time in children with SSNS.

OBJECTIVES

We describe clinical features of SSNS patients and characterize changes in calculated estimated glomerular filtration rate (eGFR) and use of antihypertensive medications during follow-up.

DESIGN

This is a retrospective cohort study.

SETTING

This study was conducted in a Canadian pediatric nephrology center.

PATIENTS

This study included patients aged 1 to 18 years with SSNS.

MEASUREMENTS

eGFR was calculated from recorded serum creatinine and height measurements using the modified Schwartz equation.

METHODS

eGFR was calculated at yearly intervals, and the trend of eGFR was assessed using linear mixed effects model. Patients were also evaluated for use of antihypertensive medications during follow-up.

RESULTS

Seventy-eight patients-median age, 3.2 years (interquartile range [IQR], 2.65) and median follow-up of 4.37 (IQR, 5.6)-were evaluated. Sixty-three (80.8%) had at least 1 relapse. Twenty-two (28.2%) and 20 (25.6%) were steroid dependent and frequently relapsing, respectively. Forty-three patients (55.1%) received at least 1 steroid-sparing agent, and of these, 18 (41.8%) received a calcineurin inhibitor. One patient had eGFR ≤90 mL/min/1.73 m² during observation. eGFR remained unchanged over the follow-up period in this cohort of patients. Four patients (5.1%) were on antihypertensive medications at the end of follow-up.

LIMITATIONS

Patients who had frequent relapses had more measurements available for serum creatinine and height, creating a sampling bias. The number of eGFR measurements was overall small, making it difficult to ascertain eGFR trend.

CONCLUSION

eGFR remained unchanged over time in this cohort, and a small proportion of patients required antihypertensive therapy at the end of follow-up. Our study highlights the needs for carefully constructed long-term observational studies of children with nephrotic syndrome.

Cell biology and genetics of minimal change disease

Minimal change disease (MCD) is an important cause of nephrotic syndrome and is characterized by massive proteinuria and hypoalbuminemia, resulting in edema and hypercholesterolemia. The podocyte plays a key role in filtration and its disruption results in a dramatic loss of function leading to proteinuria. Immunologic disturbance has been suggested in the pathogenesis of MCD. Because of its clinical features, such as recurrent relapse/remission course, steroid response in most patients, and rare familial cases, a genetic defect has been thought to be less likely in MCD. Recent progress in whole-exome sequencing reveals pathogenic mutations in familial cases in steroid-sensitive nephrotic syndrome (SSNS) and sheds light on possible mechanisms and key molecules in podocytes in MCD. On the other hand, in the majority of cases, the existence of circulating permeability factors has been implicated along with T lymphocyte dysfunction. Observations of benefit with rituximab added B cell involvement to the disease. Animal models are unsatisfactory, and the humanized mouse may be a good model that well reflects MCD pathophysiology to investigate suggested “T cell dysfunction” directly related to podocytes in vivo. Several candidate circulating factors and their effects on podocytes have been proposed but are still not sufficient to explain whole mechanisms and clinical features in MCD. Another circulating factor disease is focal segmental glomerulosclerosis (FSGS), and it is not clear if this is a distinct entity, or on the same spectrum, implicating the same circulating factor(s). These patients are mostly steroid resistant and often have a rapid relapse after transplantation. In clinical practice, predicting relapse or disease activity and response to steroids is important and is an area where novel biomarkers can be developed based on our growing knowledge of podocyte signaling pathways. In this review, we discuss recent findings in genetics and podocyte biology in MCD.

Toll-like receptor 3 expression and function in childhood idiopathic nephrotic syndrome

The efficacy of steroids and immunosuppressive treatments in idiopathic nephrotic syndrome (INS) hints at the implication of immune cells in the pathophysiology of the disease. Toll-like receptor (TLR) dysfunctions are involved in many kidney diseases of immune origin, but remain little described in INS. We investigated the expression and function of TLRs in peripheral blood mononuclear cells (PBMC) of INS children, including 28 in relapse, 23 in remission and 40 controls. No child had any sign of infection, but a higher Epstein-Barr virus viral load was measured in the PBMC of relapsing patients. TLR-3 expression was increased in B cells only during INS remission. There was a negative correlation between proteinuria and TLR-3 expression in total and the main subsets of PBMC from INS patients. The expression of TLR-8 was also increased in both CD4(+) T cells and B cells in INS remission. There was a negative correlation between proteinuria and TLR-8 expression in total PBMC, CD4(+) T cells and B cells of INS patients. Nevertheless, TLR-3 and TLR-8 expression was normalized in all PBMC subsets in an additional group of 15 INS patients in remission with B cell repletion after rituximab therapy. Paradoxically, interferon (IFN) regulatory factor 3 transactivation was increased in PBMC of all INS patients. In-vitro secretion of IFN-α and interleukin 6 were increased spontaneously in PBMC of INS remission patients, whereas PBMC from all INS patients displayed an impaired IFN-α secretion after TLR-3 stimulation. Thus, TLR-3 pathway dysfunctions may be closely involved in INS pathogenesis.

Steroid-sensitive nephrotic syndrome in children: triggers of relapse and evolving hypotheses on pathogenesis

Nephrotic syndrome remains the most common manifestation of glomerular disease in childhood. Minimal change nephropathy is the most common cause of the syndrome in children. Despite its initial high response rate to corticosteroids and its favorable prognosis, relapses are common leading to increased morbidity and cost of treatment.This review seeks to appraise the common triggers of relapse and to highlight the evolving hypotheses about the pathogenesis of the syndrome. Literature search was conducted through PubMed, Google web search and Cochrane Database of Systematic reviews using relevant search terms.Acute respiratory infections and urinary tract infections are the most frequent infectious triggers of relapse. Targeted interventions like initiating corticosteroid or its dose-adjustment during episodes of acute respiratory infection and zinc supplementation are reportedly effective in reducing relapse rates. Hypotheses on pathogenesis of the syndrome have evolved from the concepts of 'immune dysregulation', 'increased glomerular permeability' to 'podocytopathy'.Although development of drugs which can regulate the pathways for podocyte injury offers future hope for effective and targeted treatment, the relapse-specific interventions currently contribute to significant reduction in disease morbidity.