Steroid-sensitive nephrotic syndrome: from childhood to adulthood

Impact of childhood nephrotic syndrome on obesity and growth: a prospective cohort study

BACKGROUND

Children with nephrotic syndrome are at risk of obesity and growth impairment from repeated steroid treatment. However, incidence and risk factors for obesity and short stature remain uncertain, which is a barrier to preventative care. Our aim was to determine risk, timing, and predictors of obesity and short stature among children with nephrotic syndrome.

METHODS

We evaluated obesity and longitudinal growth among children (1-18 years) enrolled in Insight into Nephrotic Syndrome: Investigating Genes, Health, and Therapeutics. We included children with nephrotic syndrome diagnosed between 1996-2019 from the Greater Toronto Area, Canada, excluding congenital or secondary nephrotic syndrome. Primary outcomes were obesity (body mass index Z-score ≥  + 2) and short stature (height Z-score ≤ -2). We evaluated prevalence of obesity and short stature at enrolment (< 1-year from diagnosis) and incidence during follow-up. Cox proportional hazards models determined the association between nephrotic syndrome classification and new-onset obesity and short stature.

RESULTS

We included 531 children with nephrotic syndrome (30% frequently relapsing by 1-year). At enrolment, obesity prevalence was 23.5%, 51.8% were overweight, and 4.9% had short stature. Cumulative incidence of new-onset obesity and short stature over median 4.1-year follow-up was 17.7% and 3.3% respectively. Children with frequently relapsing or steroid dependent nephrotic syndrome within 1-year of diagnosis were at increased risk of new-onset short stature (unadjusted hazard ratio 3.99, 95%CI 1.26-12.62) but not obesity (adjusted hazard ratio 1.56, 95%CI 0.95-2.56). Children with ≥ 7 and ≥ 15 total relapses were more likely to develop obesity and short stature, respectively.

CONCLUSIONS

Obesity is common among children with nephrotic syndrome early after diagnosis. Although short stature was uncommon overall, children with frequently relapsing or steroid dependent disease are at increased risk of developing short stature. Effective relapse prevention may reduce steroid toxicity and the risk of developing obesity or short stature.

Feasibility of discontinuing immunosuppression in children with idiopathic nephrotic syndrome

BACKGROUND

Despite adverse events associated with the long-term use of immunosuppressants, their long-term discontinuation remains challenging in children with idiopathic nephrotic syndrome. Relapse and resumption of immunosuppressants after discontinuation and associated risk factors were analyzed.

METHODS

This single-center retrospective cohort study included children with frequently relapsing/steroid-dependent nephrotic syndrome (FRNS/SDNS) or steroid-resistant nephrotic syndrome (SRNS) who initiated immunosuppressant treatment between 2010 and 2020. Patients treated with immunosuppressants for less than two years, those with genetic SRNS, and those with continuation of immunosuppressants were excluded.

RESULTS

Sixty-eight patients with FRNS/SDNS or SRNS discontinued immunosuppressants. Discontinuation of immunosuppressants was more frequently tried in patients with less relapse on initial immunosuppressants and less rituximab administration. Of 68 patients who discontinued immunosuppressants, 45 (66%) relapsed and 31 (46%) resumed immunosuppressants with a median follow-up of 39.8 months (IQR 24.6-71.2 months) after discontinuation. The relapse-free survival rates were 40.0%, 35.3%, and 35.3% in 1, 2, and 3 years from discontinuation of immunosuppressants, respectively. Relapse on initial immunosuppressants (HR 2.038, 95%CI 1.006-4.128, P = 0.048) and the relapse-free interval before discontinuation of immunosuppressants (HR 0.971, 95%CI 0.944-0.998, P = 0.037) were significant risk factors associated with relapse after the discontinuation of immunosuppressants, adjusting for sex, age at immunosuppressant treatment initiation, SRNS, and rituximab use.

CONCLUSIONS

Long-term discontinuation of immunosuppressants can be feasible in patients without a relapse on initial immunosuppressants, those with longer relapse-free interval before discontinuation of immunosuppressants, and those without a relapse for one year after discontinuation of immunosuppressants.

TRIAL REGISTRATION

Not applicable.

Early Rituximab as an Add-On Therapy in Children With the Initial Episode of Nephrotic Syndrome

Introduction

The approximately 70% 12-month relapse in children experiencing the initial episode of steroid-sensitive nephrotic syndrome (SSNS) is a significant concern, with over 50% developing frequent relapses or steroid-dependent nephrotic syndrome (FRNS/SDNS). There is a lack of strategies to reduce relapse after the onset. Whether early administration of rituximab, which effectively reduces relapses in FRNS/SDNS, may be a solution has not been evaluated.

Methods

A prospective, multicenter, open-label, single-arm trial was conducted in China, with a 12-month follow-up. Children aged 1 to 18 years with the first episode of nephrotic syndrome (NS) were screened for eligibility. Proteinuria was evaluated daily using dipsticks. A dose of 375 mg/m2 of rituximab was intravenously infused within 1 week after achieving corticosteroid-induced remission. The main outcome was 12-month relapse-free survival.

Results

Out of the initially 66 children screened, 44 were enrolled and received rituximab, with all but 1 participant completing the 12-month follow-up. The median age at diagnosis was 4.3 years (interquartile range [IQR]: 3.4-5.9), and 33 (77%) of the participants were male. In the rituximab group, the 12-month relapse-free survival was significantly higher compared to historical controls (32 of 43 [74.4%] vs. 10 of 33 [30.3%]; P < 0.001; hazard ratio [HR], 3.76; 95% confidence interval [CI], 1.80-7.81). The post hoc analysis revealed a higher 24-month relapse-free survival and a lower incidence of FRNS/SDNS at the 12-month follow-up. Treatment with rituximab was well-tolerated.

Conclusion

Our findings support that early administration of rituximab may be associated with a higher 12-month relapse-free survival and a reduced incidence of FRNS/SDNS in children experiencing the initial episode of SSNS.

Podocyte number and glomerulosclerosis indices are associated with the response to therapy for primary focal segmental glomerulosclerosis

Corticosteroid therapy, often in combination with inhibition of the renin-angiotensin system, is first-line therapy for primary focal and segmental glomerulosclerosis (FSGS) with nephrotic-range proteinuria. However, the response to treatment is variable, and therefore new approaches to indicate the response to therapy are required. Podocyte depletion is a hallmark of early FSGS, and here we investigated whether podocyte number, density and/or size in diagnostic biopsies and/or the degree of glomerulosclerosis could indicate the clinical response to first-line therapy. In this retrospective single center cohort study, 19 participants (13 responders, 6 non-responders) were included. Biopsies obtained at diagnosis were prepared for analysis of podocyte number, density and size using design-based stereology. Renal function and proteinuria were assessed 6 months after therapy commenced. Responders and non-responders had similar levels of proteinuria at the time of biopsy and similar kidney function. Patients who did not respond to treatment at 6 months had a significantly higher percentage of glomeruli with global sclerosis than responders (p < 0.05) and glomerulosclerotic index (p < 0.05). Podocyte number per glomerulus in responders was 279 (203-507; median, IQR), 50% greater than that of non-responders (186, 118-310; p < 0.05). These findings suggest that primary FSGS patients with higher podocyte number per glomerulus and less advanced glomerulosclerosis are more likely to respond to first-line therapy at 6 months. A podocyte number less than approximately 216 per glomerulus, a GSI greater than 1 and percentage global sclerosis greater than approximately 20% are associated with a lack of response to therapy. Larger, prospective studies are warranted to confirm whether these parameters may help inform therapeutic decision making at the time of diagnosis of primary FSGS.

Adult survivors of childhood-onset steroid-dependent and steroid-resistant nephrotic syndrome treated with cyclosporine: a long-term single-center experience

BACKGROUND

Although evidence has confirmed that cyclosporine (CS) is efficacious against childhood-onset steroid-dependent and steroid-resistant nephrotic syndrome (SD/SRNS), some patients may continue to relapse during adulthood. However, predictive factors for adult active disease and kidney complications, such as chronic kidney disease (CKD) and hypertension, in this cohort remain unknown.

METHODS

We conducted a retrospective study on the long-term outcomes of 81 young adults with childhood-onset SD/SRNS treated with CS. The primary endpoint was the probability of active disease into adulthood. The secondary endpoint was the probability of developing kidney complications.

RESULTS

At the last follow-up (median age, 23.2 years; median disease duration, 15.8 years), 44 adult patients (54%) continued to have active disease, whereas 16 patients developed CKD or hypertension, respectively. The proportion of patients developing kidney complications was similar between the active disease and long-term remission groups. Young age at NS onset and history of relapse during the initial CS (median, 31 months) were independent predictive factors for active disease. Acute kidney injury at NS onset, focal segmental glomerulosclerosis, and irreversible CS nephrotoxicity were identified as risk factors for the development of CKD, whereas older age was identified as a risk factor for the development of CKD and hypertension.

CONCLUSIONS

More than 50% of adult survivors treated with CS continued to have active disease, and each 20% developed CKD or hypertension. A long-term follow-up is necessary for patients with SD/SRNS to identify the development of kidney complications later in adulthood that can be attributed to prior disease and CS treatment in childhood, irrespective of disease activity. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical Predictors of Steroid Resistance in Childhood Nephrotic Syndrome

We aimed to evaluate the clinical parameters, histopathological findings of nephrotic syndrome (NS) patients, and independent factors predicting steroid resistance in a single tertiary center. One hundred and sixty-two children (57 girls and 105 boys) with NS who were followed between 1998 and 2018 were analyzed in this retrospective cohort. The median (interquartile range; range) age and follow-up time were 4.9 (5.7; 0.1-16.8) and 5.5 (5.4; 0.1-20.3) years. A total of 82.7% of the patients were steroid-sensitive nephrotic syndrome (SSNS) and 17.3% were steroid-resistant nephrotic syndrome (SRNS). The median age at first presentation was lower in the SSNS group (P = .002). The most common histopathological findings were focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD). Hypertension and macroscopic and microscopic hematuria were higher in the SRNS group (P < .001). The age and microscopic hematuria were independent risk factors for steroid resistance (P = .019 and P = .002, respectively). Complement 3 (C3) was evaluated in 148 patients and found low in 7 patients who were subsequently diagnosed as membranoproliferative glomerulonephritis. There is still no better clinical predictor for steroid response than late age of onset and microscopic hematuria. Hypertension may also give a hint for potential steroid resistance.

Obinutuzumab in Frequently Relapsing and Steroid-Dependent Nephrotic Syndrome in Children

BACKGROUND

B-cell depletion with rituximab induces sustained remission in children with steroid-dependent or frequently relapsing nephrotic syndrome. However, most patients relapse after B-cell recovery, and some patients do not achieve B-cell depletion. Obinutuzumab is a second-generation anti-CD20 antibody designed to overcome such situations in B-cell malignancies and was recently reported to be safe and effective in other autoimmune diseases affecting the kidneys.

METHODS

We retrospectively report 41 children with steroid-dependent or frequently relapsing nephrotic syndrome treated with a single low-dose infusion of obinutuzumab at Robert-Debre Hospital between April 2018 and December 2020. Participants were treated because of rituximab resistance or relapse after rituximab and received a single infusion of 300 mg/1.73 m 2 obinutuzumab with cessation of oral immunosuppressors within 2 months.

RESULTS

B-cell depletion was achieved in all participants and lasted a median of 8.3 months (interquartile range, 6.4-11.1), a duration exceeding that for last rituximab treatment. At 12 and 24 months, 92% (38/41) and 68% (28/41) of patients, respectively, were in sustained remission. Mild infusion reactions occurred in five participants (12%) and neutropenia in nine (21%). No significant decrease in IgG level was reported during treatment, and whereas IgM levels decreased in 34 patients (83%), they were normal at last follow-up in 32 (78%).

CONCLUSIONS

These results identified low-dose obinituzumab as a promising treatment option in children with steroid-dependent or frequently relapsing nephrotic syndrome, including those resistant to rituximab. The tolerance profile of obinutuzumab was similar to that of rituximab, but hemogram and immunoglobulin levels should be monitored.

Predictive factors of long-term disease remission after rituximab administration in patients with childhood-onset complicated steroid-dependent nephrotic syndrome: a single-center retrospective study

BACKGROUND

Despite the fact that rituximab (RTX)-associated adverse events may be relatively frequent in younger patients, recent studies have reported RTX as a suitable first-line steroid-sparing agent for maintaining remission in children with steroid-dependent nephrotic syndrome (SDNS). However, the impact of age at RTX initiation on the long-term outcome remains unknown in this cohort.

METHODS

We retrospectively reviewed the clinical course of 61 patients with complicated SDNS who received a single dose of RTX (375 mg/m2) followed by maintenance immunosuppressive agents (IS) from January 2008 to March 2021. In patients who achieved > 12 months of prednisolone-free remission, IS tapering within 6 months was tried to achieve. The primary endpoint was the probability of achieving long-term treatment-free remission at the last follow-up.

RESULTS

After RTX initiation, 52 patients (85.2%) relapsed after a median of 665 days, and 44 patients (72.1%) received additional RTX doses (total, 226 infusions). At the last follow-up (median observation period, 8.3 years; median age, 18.3 years), 16 patients (26.2%) achieved long-term remission. Multivariate analysis showed that older age at RTX initiation was the independent predictive factor for achieving long-term remission (odds ratio, 1.25; p < 0.05). The proportion of those who achieved long-term remission was significantly higher in patients aged ≥ 13.5 years than in those aged < 13.5 years at RTX initiation (52.6 vs 14.3%, p < 0.05). Persistent severe hypogammaglobulinemia did not develop in older children (≥ 13.5 years) at RTX initiation.

CONCLUSION

For older children with complicated SDNS, RTX appeared to be a suitable disease-modifying therapy without persistent adverse events.

A phase I study of autologous mesenchymal stromal cells for severe steroid-dependent nephrotic syndrome

BACKGROUNDSevere forms of idiopathic nephrotic syndrome (INS) require prolonged immunosuppressive therapies and repeated courses of high-dose glucocorticoids. Mesenchymal stromal cells (MSCs) have promising immunomodulatory properties that may be employed therapeutically to reduce patient exposure to medications and their side effects.METHODSWe performed a phase I open-label trial assessing safety and feasibility of autologous bone marrow-derived MSCs (BM-MSCs) in children and young adults with severe forms of steroid-dependent nephrotic syndrome. Following autologous BM-MSC preparation and infusion, oral immunosuppression was tapered. Safety, efficacy, and immunomodulatory effects in vivo were monitored for 12 months.RESULTSSixteen patients (10 children, 6 adults) were treated. Adverse events were limited and not related to BM-MSC infusions. All patients relapsed during follow-up, but in the 10 treated children, time to first relapse was delayed (P = 0.02) and number of relapses was reduced (P = 0.002) after BM-MSC infusion, compared with the previous 12 months. Cumulative prednisone dose was also reduced at 12 months compared with baseline (P < 0.05). No treatment benefit was observed in adults.In children, despite tapering of immunosuppression, clinical benefit was mirrored by a significant reduction in total CD19+, mature, and memory B cells and an increase in regulatory T cells in vivo up to 3-6 months following BM-MSC infusionCONCLUSIONTreatment with autologous BM-MSCs is feasible and safely reduces relapses and immunosuppression at 12 months in children with severe steroid-dependent INS. Immunomodulatory studies suggest that repeating MSC infusions at 3-6 months may sustain benefit.TRIAL REGISTRATIONEudraCT 2016-004804-77.FUNDINGAIFA Ricerca Indipendente 2016-02364623.

Childhood nephrotic syndrome

Idiopathic nephrotic syndrome is the most common glomerular disease in children. Corticosteroids are the cornerstone of its treatment, and steroid response is the main prognostic factor. Most children respond to a cycle of oral steroids, and are defined as having steroid-sensitive nephrotic syndrome. Among the children who do not respond, defined as having steroid-resistant nephrotic syndrome, most respond to second-line immunosuppression, mainly with calcineurin inhibitors, and children in whom a response is not observed are described as multidrug resistant. The pathophysiology of nephrotic syndrome remains elusive. In cases of immune-mediated origin, dysregulation of immune cells and production of circulating factors that damage the glomerular filtration barrier have been described. Conversely, up to a third of cases of steroid-resistant nephrotic syndrome have a monogenic origin. Multidrug resistant nephrotic syndrome often leads to kidney failure and can cause relapse after kidney transplant. Although steroid-sensitive nephrotic syndrome does not affect renal function, most children with steroid-sensitive nephrotic syndrome have a relapsing course that requires repeated steroid cycles with significant side-effects. To minimise morbidity, some patients require steroid-sparing immunosuppressive agents, including levamisole, mycophenolate mofetil, calcineurin inhibitors, anti-CD20 monoclonal antibodies, and cyclophosphamide. Close monitoring and preventive measures are warranted at onset and during relapse to prevent acute complications (eg, hypovolaemia, acute kidney injury, infections, and thrombosis), whereas long-term management requires minimising treatment-related side-effects. A subset of patients have active disease into adulthood.

Multi-population genome-wide association study implicates immune and non-immune factors in pediatric steroid-sensitive nephrotic syndrome

Pediatric steroid-sensitive nephrotic syndrome (pSSNS) is the most common childhood glomerular disease. Previous genome-wide association studies (GWAS) identified a risk locus in the HLA Class II region and three additional independent risk loci. But the genetic architecture of pSSNS, and its genetically driven pathobiology, is largely unknown. Here, we conduct a multi-population GWAS meta-analysis in 38,463 participants (2440 cases). We then conduct conditional analyses and population specific GWAS. We discover twelve significant associations-eight from the multi-population meta-analysis (four novel), two from the multi-population conditional analysis (one novel), and two additional novel loci from the European meta-analysis. Fine-mapping implicates specific amino acid haplotypes in HLA-DQA1 and HLA-DQB1 driving the HLA Class II risk locus. Non-HLA loci colocalize with eQTLs of monocytes and numerous T-cell subsets in independent datasets. Colocalization with kidney eQTLs is lacking but overlap with kidney cell open chromatin suggests an uncharacterized disease mechanism in kidney cells. A polygenic risk score (PRS) associates with earlier disease onset. Altogether, these discoveries expand our knowledge of pSSNS genetic architecture across populations and provide cell-specific insights into its molecular drivers. Evaluating these associations in additional cohorts will refine our understanding of population specificity, heterogeneity, and clinical and molecular associations.

T-cell receptor diversity in minimal change disease in the NEPTUNE study

BACKGROUND

Minimal change disease (MCD) is the major cause of childhood idiopathic nephrotic syndrome, which is characterized by massive proteinuria and debilitating edema. Proteinuria in MCD is typically rapidly reversible with corticosteroid therapy, but relapses are common, and children often have many adverse events from the repeated courses of immunosuppressive therapy. The pathobiology of MCD remains poorly understood. Prior clinical observations suggest that abnormal T-cell function may play a central role in MCD pathogenesis. Based on these observations, we hypothesized that T-cell responses to specific exposures or antigens lead to a clonal expansion of T-cell subsets, a restriction in the T-cell repertoire, and an elaboration of specific circulating factors that trigger disease onset and relapses.

METHODS

To test these hypotheses, we sequenced T-cell receptors in fourteen MCD, four focal segmental glomerulosclerosis (FSGS), and four membranous nephropathy (MN) patients with clinical data and blood samples drawn during active disease and during remission collected by the Nephrotic Syndrome Study Network (NEPTUNE). We calculated several T-cell receptor diversity metrics to assess possible differences between active disease and remission states in paired samples.

RESULTS

Median productive clonality did not differ between MCD active disease (0.0083; range: 0.0042, 0.0397) and remission (0.0088; range: 0.0038, 0.0369). We did not identify dominant clonotypes in MCD active disease, and few clonotypes were shared with FSGS and MN patients.

CONCLUSIONS

While these data do not support an obvious role of the adaptive immune system T-cells in MCD pathogenesis, further study is warranted given the limited sample size. A higher resolution version of the Graphical abstract is available as Supplementary information.

Long-term complications in patients with childhood-onset nephrotic syndrome

BACKGROUND

Reports on long-term complications of childhood-onset nephrotic syndrome (NS), such as obesity, osteoporosis, growth failure, and hypertension, are mostly from developed countries not representing South Asian ethnicities. Furthermore, data on cardiovascular health among patients with childhood-onset NS are limited.

METHODS

This was an observational study involving patients attending a tertiary care center. Patients aged 15 years and older were examined for long-term complications and remission of NS at their visit in December 2021. Childhood-onset NS meant onset of NS before 10 years of age. Long-term complications included obesity, growth failure, low bone mineral density (BMD) Z score, hypertension, and increased carotid intima-media thickness (cIMT). Long-term remission was defined as no relapse for the last [Formula: see text] 3 consecutive years without immunosuppressive medication to maintain remission.

RESULTS

Of 101 patients studied (~ 80% with frequent relapsing (FR)/steroid-dependent (SD) NS), the mean age was 17.6 (± 2.4) years at the time of study. Long-term complications were noted in 89.1% of patients which included one or more of the following: obesity (22.7%), growth failure (31.7%), low BMD Z score (53.5%), hypertension (31.7%), and high cIMT (50.5%). Thirty-nine patients (38.6%) were in long-term remission at the time of the study. Growth failure and low BMD Z scores were less frequent in patients with long-term remission compared to those without long-term remission.

CONCLUSIONS

In patients with childhood-onset NS (predominantly FR/SDNS) who were studied at [Formula: see text] 15 years of age, ~ 90% had long-term complications which included high cIMT in 50%. Only ~ 40% were in long-term remission. A higher resolution version of the Graphical abstract is available as Supplementary information.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome

Rituximab is an established therapy in children with idiopathic nephrotic syndrome to sustain short- to medium-term disease remission and avoid steroid toxicities. Recent trials focus on its use as a first-line agent among those with milder disease severity. Rituximab is used in multidrug refractory nephrotic syndrome and post-transplant disease recurrence, although the evidence is much less substantial. Available data suggest that the treatment response to rituximab depends on various patient factors, dosing regimen, and the concomitant use of maintenance immunosuppression. After repeated treatments, patients are found to have an improving response overall with a longer relapse-free period. The drug effect, however, is not permanent, and 80% of patients eventually relapse and many will require an additional course of rituximab. This underpins the importance of understanding the long-term safety profile on repeated treatments. Although rituximab appears to be generally safe, there are concerns about long-term hypogammaglobulinemia, especially in young children. Reliable immunophenotyping and biomarkers are yet to be discovered to predict treatment success, risk of both rare and severe side effects, e.g. , persistent hypogammaglobulinemia, and guiding of redosing strategy. In this review, we highlight recent advances in the use of rituximab for childhood nephrotic syndrome and how the therapeutic landscape is evolving.

Therapeutic trials in difficult to treat steroid sensitive nephrotic syndrome: challenges and future directions

Steroid sensitive nephrotic syndrome is a common condition in pediatric nephrology, and most children have excellent outcomes. Yet, 50% of children will require steroid-sparing agents due to frequently relapsing disease and may suffer consequences from steroid dependence or use of steroid-sparing agents. Several steroid-sparing therapeutic agents are available with few high quality randomized controlled trials to compare efficacy leading to reliance on observational data for clinical guidance. Reported trials focus on short-term outcomes such as time to first relapse, relapse rates up to 1-2 years of follow-up, and few have studied long-term remission. Trial designs often do not consider inter-individual variability, and differing response to treatments may occur due to heterogeneity in pathogenic mechanisms, and genetic and environmental influences. Strategies are proposed to improve the quantity and quality of trials in steroid sensitive nephrotic syndrome with integration of biomarkers, novel trial designs, and standardized outcomes, especially for long-term remission. Collaborative efforts among international trial networks will help move us toward a shared goal of finding a cure for children with nephrotic syndrome.

Nephrotic Syndrome and Renin-angiotensin System: Pathophysiological Role and Therapeutic Potential

Idiopathic Nephrotic Syndrome (INS) is the most frequent etiology of glomerulopathy in pediatric patients and one of the most common causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in this population. In this review, we aimed to summarize evidence on the pathophysiological role and therapeutic potential of the Renin-Angiotensin System (RAS) molecules for the control of proteinuria and for delaying the onset of CKD in patients with INS. This is a narrative review in which the databases PubMed, Web of Science, and Sci- ELO were searched for articles about INS and RAS. We selected articles that evaluated the pathophysiological role of RAS and the effects of the alternative RAS axis as a potential therapy for INS. Several studies using rodent models of nephropathies showed that the treatment with activators of the Angiotensin-Converting Enzyme 2 (ACE2) and with Mas receptor agonists reduces proteinuria and improves kidney tissue damage. Another recent paper showed that the reduction of urinary ACE2 levels in children with INS correlates with proteinuria and higher concentrations of inflammatory cytokines, although data with pediatric patients are still limited. The molecules of the alternative RAS axis comprise a wide spectrum, not yet fully explored, of potential pharmacological targets for kidney diseases. The effects of ACE2 activators and receptor Mas agonists show promising results that can be useful for nephropathies including INS.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-sensitive nephrotic syndrome

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given.

Current Understanding of Nephrotic Syndrome in Children

Nephrotic syndrome in children is mostly idiopathic in origin. About 90% of patients respond to corticosteroids; 80-90% have at least one relapse and 3-10% become corticosteroid resistant after the initial response. A kidney biopsy is seldom indicated for diagnosis except in patients with atypical presentation or corticosteroid resistance. For those in remission, the risk of relapse is reduced by the administration of daily low dose corticosteroids for 5-7 days at the onset of an upper respiratory infection. Some patients may continue having relapses through adult life. Many country-specific practice guidelines have been published, which are very similar with clinically insignificant differences.

Treatment of idiopathic nephrotic syndrome at onset: a comparison between 8- and 12-week regimens in everyday clinical practice

BACKGROUND

Optimal steroid treatment at onset of idiopathic nephrotic syndrome is still debated. The aim of this study was to analyze the clinical outcome at 24 months of follow-up in patients admitted to our unit for the first episode of steroid-sensitive nephrotic syndrome comparing two different steroid regimens.

METHODS

We collected data on patients treated from 1992 to 2007 with prednisone according to the International Study on Kidney Diseases in Children 8-week regimen and since 2008 according to the Arbeitsgemeinschaft fur Padiatrische Nephrologie 12-week regimen. The primary outcome was to evaluate cumulative prednisone dosage at 12 and 24 months of follow-up in the two groups. As secondary outcomes, we considered mean relapse rate per patient; number of children without relapses at 6, 12, and 24 months; and number of patients who developed frequent relapses and steroid-dependent disease.

RESULTS

Data were collected on 127 patients. Sixty-one subjects received the 8-week regimen and 66 the 12-week regimen. The mean cumulative prednisone dose at 12 and 24 months was not different, and the rate of patients without relapses was lower at 6 and 12 months in patients treated with the 8-week course, while no difference was observed at 24 months.

CONCLUSIONS

Despite the limitations of a retrospective study with limited follow-up, our data indicate that switching treatment from a shorter to a longer scheme did not improve the clinical outcome at 24 months of observation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Rates of idiopathic childhood nephrotic syndrome relapse are lower during the COVID-19 pandemic

BACKGROUND

Infections are thought to be primarily responsible for triggering relapse in children with steroid-sensitive nephrotic syndrome (NS). The COVID-19 pandemic promoted physical distancing, facial mask wearing, and greater attention to infection-prevention measures resulting in decreased transmission of infections. We hypothesized there would also be a decreased rate of NS relapse during this period.

METHODS

We conducted a single-center retrospective chart review of children with steroid-sensitive NS. Demographics, rate of relapses, and rate of hospitalizations were collected for a baseline pre-pandemic period (BPP) and for the social distancing period during the pandemic (SDP).

RESULTS

One hundred twenty-two children with primary steroid-sensitive NS were identified and 109 were followed for the duration of the study period. The paired rate of relapse per subject per year was significantly lower during the SDP (0.6 relapses per subject per year ± 1 SD) compared to the BPP (1.0 relapses per subject per year ± 0.9 SD), P &lt; 0.01. A subgroup of 32 subjects who were newly diagnosed with NS during the BPP similarly had significantly fewer relapses during the SDP (0.8 ± 1 SD) than during the BPP (1.4 ± 1 SD), P = 0.01.

CONCLUSIONS

Our results support the hypothesis of lower rates of NS relapse and hospitalizations during social distancing for all subjects in our cohort and a subgroup of those newly diagnosed. Lower relapse rates were likely attributable to decreased transmission of infections and greater attention to infection prevention. A higher resolution version of the Graphical abstract is available as Supplementary information.

Assessment of Brain-Derived Neurotrophic Factor (BDNF) Concentration in Children with Idiopathic Nephrotic Syndrome

Idiopathic nephrotic syndrome (INS) is a chronic disease affecting children in early childhood. It is characterized by proteinuria, hypoalbuminemia, edema and hyperlipidemia. To date, the diagnosis is usually established at an advanced stage of proteinuria. Therefore, new methods of early INS detection are desired. This study was designed to assess brain-derived neurotrophic factor (BDNF) as a potential marker in the early diagnosis of INS. The study group included patients with a diagnosis of idiopathic nephrotic syndrome (n = 30) hospitalized in Clinical Hospital No. 1 in Zabrze, from December 2019 to December 2021. Our study shows that serum BDNF concentration decreased and urine BDNF concentration increased in a group of patients with INS, compared with healthy controls. Such outcomes might be related to loss of the BDNF contribution in podocyte structure maintenance. Moreover, we anticipate the role of BDNF in urine protein concentration increase, which could be used as a direct predictor of urine protein fluctuations in clinical practice. Moreover, the ROC curve has also shown that serum BDNF and urine BDNF levels might be useful as an INS marker.

Haemostatic profile of children with nephrotic syndrome attending University of Nigeria Teaching Hospital Ituku-Ozalla, Nigeria

Background

Haemostatic derangements are thought to be due to an imbalance between hepatic synthesis of pro-coagulants and urinary losses of anticoagulants.

Objectives

This study evaluated the coagulation profile of Nigerian children with nephrotic syndrome and examined the relationship between coagulation variables, disease state and steroid responsiveness.

Methods

A cross- sectional hospital based study on evaluation of coagulation profile of children with nephrotic syndrome compared with their age- and gender- matched controls.

Results

The median fibrinogen level in subjects and controls was the same (2.9 g/L). Sixteen of 46 (35%) children with nephrotic syndrome had hyperfibrinogenaemia. The median fibrinogen level of children in remission was 2.3 g/L and differed significantly when compared with those of children in relapse (p = 0.001). The median APTT of children with nephrotic syndrome was 45.0 s and differed significantly compared with those of controls (42.0 s) (p value = 0.02). The median prothrombin time in children with and without nephrotic syndrome were 12.0 and 13.0 s respectively, (p = 0.004). About 90% of children with nephrotic syndrome had INR within reference range. Thrombocytosis was found in 15% of children with nephrotic syndrome. The median platelet count in children with new disease was 432 × 10³cells/mm³ and differed significantly when compared with those of controls (p = 0.01).

INR was significantly shorter in children with steroid resistant nephrotic syndrome (SRNS) (median 0.8 s; IQR 0.8 -0.9 s) compared with controls (median 1.0 s; IQR 1.0 -1.1 s) (p = 0.01). Steroid sensitivity was the strongest predictor of remission in children with nephrotic syndrome; steroid sensitive patients were 30 times more likely to be in remission than in relapse (OR 30.03; CI 2.01 – 448.04).

Conclusion

This study shows that the haemostatic derangements in childhood nephrotic involve mostly fibrinogen, APTT, PT, INR and platelet counts. Antithrombin levels are largely unaffected. Variations in fibrinogen, APTT, PT and INR values may be due to the heterogeneous nature of the disease.

Long-term obesity prevalence and linear growth in children with idiopathic nephrotic syndrome: is normal growth and weight control possible with steroid-sparing drugs and low-dose steroids for relapses?

BACKGROUND

Long-term steroid treatment in children is known to cause obesity and negatively affect growth. The objective of this study was to determine the prevalence of obesity and overweight and analyze linear growth in children with nephrotic syndrome.

METHODS

The study involved 265 children treated with glucocorticoids for nephrotic syndrome for a mean duration of 43 months (range: 6-167, IQR: 17, 63.3). Height, weight, and BMI SDS were recorded at each visit. Rate of change between the final and initial height, weight, and BMI was calculated (Δ score). The cumulative steroid dose (mg/kg/day) during follow-up was calculated. Relapses without significant edema were treated with low-dose steroids and steroid-sparing drugs were used in children with steroid dependency/frequent relapses.

RESULTS

Mean first BMI SDS was + 1.40 ± 1.30 and final + 0.79 ± 1.30. At initial assessment, 41.4% of the patients were obese (BMI ≥ 95^th percentile) and 19.5% were overweight (BMI 85^th-95^th percentile). At the last clinical visit, 24% were obese and 17% overweight. The children had lower BMI SDS at last clinical visit compared to initial assessment. Mean first height SDS of the cohort was - 0.11 ± 1.22 and final score 0.078 ± 1.14 (p < 0.0001). Almost 85% of patients were treated with steroid-sparing drugs.

CONCLUSIONS

Our results indicate that children with nephrotic syndrome, despite a need for steroid treatment for active disease, can improve their obesity and overweight and also improve their linear growth from their first to last visit with us.

The causes and consequences of paediatric kidney disease on adult nephrology care

Adult nephrologists often look after patients who have been diagnosed with kidney disease in childhood. This does present unique challenges to the adult nephrologist, who may be unfamiliar with the underlying cause of kidney disease as well as the complications of chronic kidney disease (CKD) that may have accumulated during childhood. This review discusses common causes of childhood CKD, in particular congenital anomalies of the kidney and urinary tract (CAKUT), autosomal dominant tubulointerstitial kidney disease (ADTKD), polycystic kidney disease, hereditary stone disease, nephrotic syndrome and atypical haemolytic uraemic syndrome. The long-term consequences of childhood CKD, such as the cardiovascular consequences, cognition and education as well as bone health, nutrition and growth are also discussed.

Idiopathic Nephrotic Syndrome in Pediatrics: An Up-to-date

BACKGROUND

Idiopathic or Primary Nephrotic Syndrome (INS) is a common glomerular disease in pediatric population, characterized by proteinuria, edema and hypoalbuminemia with variable findings in renal histopathology.

OBJECTIVE

This review aims to summarize current data on the etiopathogenesis diagnosis, protocols of treatment and potential therapeutic advances in INS.

METHODS

This narrative review searched for articles on histopathology, physiopathology, genetic causes, diagnosis and treatment of INS in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

INS is caused by an alteration in the permeability of the glomerular filtration barrier with unknown etiology. There are several gaps in the etiopathogenesis, response to treatment and clinical course of INS that justify further investigation. Novel advances include the recent understanding of the role of podocytes in INS and the identification of genes associated with the disease. The role of immune system cells and molecules has also been investigated. The diagnosis relies on clinical findings, laboratory exams and renal histology for selected cases. The treatment is primarily based on steroids administration. In case of failure, other medications should be tried. Recent studies have also searched for novel biomarkers for diagnosis and alternative therapeutic approaches.

CONCLUSION

The therapeutic response to corticosteroids still remains the main predictive factor for the prognosis of the disease. Genetic and pharmacogenomics tools may allow the identification of cases not responsive to immunosuppressive medications.

The Diagnostic Journey of Childhood Idiopathic Nephrotic Syndrome: Perspectives of Children and Their Caregivers

Background:

Childhood nephrotic syndrome is a rare kidney disease characterized by sudden onset of edema, massive proteinuria, and hypoalbuminemia. Rare diseases can have a long and difficult trajectory to diagnosis.

Objective:

We aimed to explore the experiences of children with nephrotic syndrome and their caregivers in their search of a nephrotic syndrome diagnosis.

Design:

An exploratory, qualitative descriptive study design.

Setting:

The Alberta Children’s Hospital outpatient nephrology program in Calgary, Alberta, Canada.

Sample:

Children aged 9 to 18 years with steroid-sensitive nephrotic syndrome and their caregivers.

Methods:

We undertook semi-structured interviews with children (alone or with a caregiver present) and their caregivers using a question guide suitable to their age and role. We used a thematic analysis approach to inductively code the data and characterize themes related to our research question.

Results:

Participants included 10 children aged 9 to 18 years (6 boys and 4 girls) and 18 caregivers (8 men and 10 women). We characterized 3 themes related to participants’ experiences in search of a diagnosis of nephrotic syndrome: (1) unexpected and distressing symptom onset, (2) elusiveness of a diagnosis, and (3) encountering a diagnosis. Children with nephrotic syndrome and their caregivers described experiencing initial anxiety due to their unusual and unexpected symptom onset and lack of awareness about the disease. Perceived diagnostic delays and incorrect diagnosis early in the course of the disease contributed to multiple consultations with a variety of care providers. Overall, participants expressed a desire to move past their diagnosis, learn about nephrotic syndrome, and engage in their treatment plans.

Limitations:

The views expressed by participants may not reflect those of individuals from other settings. The time elapsed since participants’ nephrotic syndrome diagnosis may have influenced their recall of events and reactions to this diagnosis.

Conclusions:

In characterizing the diagnostic experiences of children and their caregivers, our study provides insight into how patients with nephrotic syndrome and their caregivers can be supported by the healthcare team along this journey. Focused strategies to increase awareness and understanding of nephrotic syndrome among healthcare providers are needed to improve patients’ and families’ diagnostic experiences.

Low regulatory T-cells: A distinct immunological subgroup in minimal change nephrotic syndrome with early relapse following rituximab therapy

Rituximab is an important second line therapy in difficult nephrotic syndrome (NS), especially given toxicity of long-term glucocorticoid or calcineurin inhibitor (CNI) use. However, clinical response to rituximab is heterogenous. We hypothesized that this was underpinned by immunological differences amongst patients with NS. We recruited a cohort of 18 subjects with glucocorticoid-dependent or glucocorticoid-resistant childhood-onset minimal change NS who received rituximab either due to CNI nephrotoxicity, or due to persistent glucocorticoid toxicity with inadequate response to cyclophosphamide or CNIs. Immunological subsets, T-cell activation assays and plasma cytokines were measured at baseline and 6-months post-rituximab. Time to relapse was bifurcated: 56% relapsed within one year ("early relapse"), while the other 44% entered remission mainly lasting ≥3 years ("sustained remission"). At baseline, early relapse compared to sustained remission group had lower regulatory T-cells (Tregs) [2.94 (2.25, 3.33)% vs 6.48 (5.08, 7.24)%, P<0.001], PMA-stimulated IL-2 [0.03 (0, 1.85)% vs 4.78 (0.90, 9.18)%, P=0.014] and IFNγ [2.22 (0.18, 6.89)% vs 9.47 (2.72, 17.0)%, P=0.035] levels. Lower baseline Treg strongly predicted early relapse (ROC-AUC 0.99, 95% CI 0.97-1.00, P<0.001). There were no differences in baseline plasma cytokine levels. Following rituximab, there was significant downregulation of Th2 cytokines in sustained remission group (P=0.038). In particular, IL-13 showed a significant decrease in sustained remission group [-0.56 (-0.64, -0.35)pg/ml, P=0.007)], but not in the early relapse group. In conclusion, early relapse following rituximab is associated with baseline reductions in Treg and T-cell hyporesponsiveness, which suggest chronic T-cell activation and may be useful predictive biomarkers. Sustained remission, on the other hand, is associated with downregulation of Th2 cytokines following rituximab.

Clinical Characteristics and Outcomes of Adults with Nephrotic Syndrome Due to Minimal Change Disease

PURPOSE

Minimal change disease (MCD) is considered a relatively benign glomerulopathy, as it rarely progresses to end-stage kidney disease. The aim of this study was to describe the characteristics and outcomes of adults with MCD and identify potential risk factors for relapse.

PATIENTS & METHODS

We retrospectively studied a cohort of adults with biopsy-proven MCD in terms of clinical features and treatment outcomes. Baseline characteristics and outcomes were recorded and predictors of relapse were analyzed using logistic regression multivariate analysis.

RESULTS

59 patients with adult-onset primary MCD with nephrotic syndrome were included. Mean serum creatinine at diagnosis was 0.8 mg/dL (±2.5) and estimated GFR (eGFR) was 87 mL/min/1.73 m² (±29.5). Mean serum albumin was 2.5 g/dL (±0.8) and 24 h proteinuria 6.8 g (±3.7). Microscopic hematuria was detected in 35 (58.5%) patients. 42 patients received prednisone alone, six patients received prednisone plus cyclophosphamide, five patients received prednisone plus cyclosporine, one patient received prednisone plus rituximab and five patients did not receive immunosuppression at all since they achieved spontaneous remission. During a mean follow up time of 34.7(22.1) months, 46.1% of patients experienced at least one episode of relapse. The mean age of patients who did not experience a relapse was significantly higher than that of patients who relapsed while relapsers had a significantly longer duration of 24 h proteinuria prior to biopsy compared to non-relapsers. Overall, 10% of patients experienced acute kidney injury while the mean eGFR at the end was 82 mL/min/1.73 m² (±29.1) and one patient ended up in chronic dialysis. Overall, the proportion of non-relapsers, who experienced acute kidney injury (17%) was significantly higher than the one recorded among relapsers (0%).

CONCLUSION

In this series of patients, almost 46% of adult-onset nephrotic MCD patients experienced a relapse, although their renal progression was rare. Younger onset age was an independent risk factor for relapse in adult-onset MCD patients.

Long-term health-related quality of life outcomes of adults with pediatric onset of frequently relapsing or steroid-dependent nephrotic syndrome

BACKGROUND

Long-term psychosocial outcomes and health-related quality of life (HRQOL) in adults with pediatric onset of frequently relapsing or steroid-dependent idiopathic nephrotic syndrome (FRNS or SDNS) remain to be determined.

METHODS

In this prospective cohort study, 59 adults with pediatric onset of FRNS/SDNS and persistent active glomerular disease in adulthood completed the GEDEPAC-2 questionnaire exploring 11 well-being domains. Data were compared to the French general population (FGP) with standardized incidence ratio ([SIR]; adjusted for period, age, gender). Regression models were performed to identify predictive factors of psychosocial well-being.

RESULTS

In 82% of cases, the questionnaire was completed while the participants (n = 59; 47 men; median age = 32 years; median number of relapses = 13) were in complete remission (under specific therapy in 76% of cases). Participants had higher educational degree than in the FGP (SIR = 6.3; p < 0.01) and more frequently a managerial occupation (SIR = 3.1; p < 0.01). Social integration was acceptable with regard to marital status and experience of sexual intercourse, but experiences of discrimination were far more frequent (SIR = 12.5; p < 0.01). The SF-12 mental component summary (MCS) score was altered (Z-score = - 0.6; p < 0.01) and mean multidimensional fatigue inventory (MFI-20) global fatigue score appeared high (12). Transfer from pediatric to adult healthcare was followed by a period of discontinued care for 33% of participants. Multivariate analysis revealed a close relationship between MFI-20, physical health, and MCS.

CONCLUSIONS

This study shows that pediatric onset FRNS and SDNS may have a long-term negative impact on mental HRQOL and highlights the impact of fatigue, which is often not adequately considered in routine care.

Calcium, Vitamin D, and Bone Derangement in Nephrotic Syndrome

Introduction

Derangement in calcium homeostasis is common in nephrotic syndrome (NS). It is postulated that low serum total calcium and vitamin D levels are due to loss of protein-bound calcium and vitamin D. It is unclear if free calcium and free vitamin D levels are truly low. The guideline is lacking with regards to calcium and vitamin D supplementation in NS. This study aims to examine calcium and vitamin D homeostasis and bone turnover in NS to guide practice in calcium and vitamin D levels supplementation.

Methodology

This is a prospective pilot study of ten patients diagnosed with NS, and eight healthy controls. Calcium, vitamin D, and bone turnover-related analytes were assessed at baseline, partial and complete remission in NS patients and in healthy controls.

Results

NS patients had low free and total serum calcium, low total 25(OH)D, normal total 1,25(OH)D levels and lack of parathyroid hormone response. With remission of disease, serum calcium and vitamin D metabolites improved. However, nephrotic patients who do not attain complete disease remission continue to have low 25(OH)D level.

Conclusion

In this study, the vitamin D and calcium derangement observed at nephrotic syndrome presentation trended towards normalisation in remission. This suggested calcium and vitamin D replacement may not be indicated in early-phase nephrotic syndrome but may be considered in prolonged nephrotic syndrome.

A global antiB cell strategy combining obinutuzumab and daratumumab in severe pediatric nephrotic syndrome

BACKGROUND

Steroid-sensitive nephrotic syndrome (SSNS) is, in most patients, a chronic disease with 80% experiencing at least one relapse after first flare. B cell depletion using rituximab is effective in preventing relapse in steroid-dependent (SDNS) patients but fails to maintain long-term remission following B cell recovery, possibly due to development of autoreactive long-lived plasma cells. We investigated sequential combination of antiCD20 antibody targeting all B cell subsets, and antiCD38 antibody with high plasma cell cytotoxicity in patients with uncontrolled SDNS after failure of one or several attempts at B cell depletion.

METHODS

Fourteen patients with median disease duration 7.8 years received 1000 mg/1.73 m² obinutuzumab followed by 1000 mg/1.73 m² daratumumab 2 weeks later. Oral immunosuppression was discontinued within 6 weeks, and biological monitoring performed monthly until B cell recovery.

RESULTS

Median age at treatment was 11.0 [IQR 10.4-14.4] years. B cell depletion was achieved in all patients, and B cell reconstitution occurred in all at median 9.5 months after obinutuzumab injection. After median follow-up 20.3 months (IQR 11.5-22.6), 5/14 patients relapsed including 4 within 100 days following B cell repletion. Relapse-free survival was 60% at 24 months from obinutuzumab infusion. Mild infusion reactions were reported in 3/14 patients during obinutuzumab and 4/14 during daratumumab infusions. Mild transient neutropenia (500-1000/mm³) occurred in 2/14 patients. Intravenous immunoglobulins were given to 12/14 patients due to hypogammaglobulinemia. Low IgA and IgM levels were noted in 8 and 14 patients, respectively. No severe infection was reported.

CONCLUSION

Global antiB cell strategy combining obinutuzumab and daratumumab induces prolonged peripheral B cell depletion and remission in children with difficult-to-treat SDNS.

Pediatric idiopathic steroid-sensitive nephrotic syndrome: diagnosis and therapy -short version of the updated German best practice guideline (S2e) - AWMF register no. 166-001, 6/2020

Idiopathic nephrotic syndrome is the most frequent glomerular disease in children in most parts of the world. Children with steroid-sensitive nephrotic syndrome (SSNS) generally have a good prognosis regarding the maintenance of normal kidney function even in the case of frequent relapses. The course of SSNS is often complicated by a high rate of relapses and the associated side effects of repeated glucocorticoid (steroid) therapy. The following recommendations for the treatment of SSNS are based on the comprehensive consideration of published evidence by a working group of the German Society for Pediatric Nephrology (GPN) based on the systematic Cochrane reviews on SSNS and the guidelines of the KDIGO working group (Kidney Disease - Improving Global Outcomes).

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

Hypokalemia After Rituximab Administration in Steroid-Dependent Nephrotic Syndrome: A Case Report

The monoclonal antibody rituximab is a commonly used steroid sparing agent for steroid-dependent idiopathic nephrotic syndrome of childhood. With this brief report, we describe the first case of symptomatic hypokalemia after intravenous rituximab administration in a young woman. The sudden onset of dizziness and palpitation prompted acute life-threatening hypokalemia recognition by blood gas analysis and electrocardiography. Her symptoms were rapidly controlled by intravenous potassium administration. Such adverse drug reactions, when mild and self-limiting, can easily be overlooked if not expected or investigated. Health professionals should take into account the possibility of acute hypokalemia after rituximab administration in order to promptly setup the appropriate treatment and limit potentially severe complications.

Glucose metabolism disorders in children with refractory nephrotic syndrome

BACKGROUND

Patients with refractory nephrotic syndrome (NS) are at high risk of medication-induced glucose metabolism disorders, because of their long-term use of diabetogenic medications, particularly glucocorticoids and calcineurin inhibitors (CNIs). However, there have been no comprehensive evaluations of glucose metabolism disorders in pediatric patients with refractory NS. Moreover, glucocorticoids and CNIs could not be discontinued in these patients until the effectiveness of rituximab on refractory NS was shown, and therefore, there has been limited opportunity to evaluate glucose metabolism disorders after discontinuation of these medications.

METHODS

Consecutive pediatric patients who started rituximab treatment for refractory NS were enrolled. Their glucose metabolism conditions were evaluated using the oral glucose tolerance tests (OGTT) and HbA1c levels at the initiation of rituximab treatment. Patients with glucose metabolism disorders at the first evaluation were reevaluated after approximately 2 years.

RESULTS

Overall, 57% (20/35) of study patients had glucose metabolism disorders, and 40% (8/20) of these patients were detected only by their 2-h OGTT blood glucose levels and not by their fasting blood glucose or HbA1c levels. Non-obese/non-overweight patients had significantly more glucose metabolism disorders than obese/overweight patients (p = 0.019). In addition, glucose metabolism disorders in 71% (10/14) of patients persisted after the discontinuation of glucocorticoids and CNIs.

CONCLUSIONS

Whether the patient is obese/overweight or not, patients with refractory NS are at high risk of developing glucose metabolism disorders, even in childhood. Non-obese/non-overweight patients who are at high risk of diabetes need extra vigilance.

Treatment of nephrotic syndrome: going beyond immunosuppressive therapy

It is indisputable that immunosuppressive therapy and pathological diagnosis of renal biopsy have greatly improved the prognosis of childhood nephrotic syndrome. Unfortunately, there is no "one-size-fits-all" approach for precise patient stratification and treatment when facing the huge challenges posed by steroid-resistant nephrotic syndrome (SRNS). But genomic medicine has brought a glimmer of light, and the cognition of SRNS has entered a new stage. Based on this, identification of single genetic variants of SRNS has recognized the key role of podocyte injury in its pathogenesis. Targeted treatment of podocyte injury is paramount, and immunosuppressant with podocyte-targeted therapy seems to be more suitable as the first choice for SRNS, that is, we need to pay attention to their additional non-immunosuppressive effects. In the same way, other effect factors of nephrotic syndrome and the related causes of immunosuppressive therapy resistance require us to select reasonable and targeted non-immunosuppressive therapies, instead of only blindly using steroids and immunosuppressants, which may be ineffective and bring significant side effects. This article provides a summary of the clinical value of identification of genetic variants in podocytes and non-immunosuppressive therapy for nephrotic syndrome in children.

Review on long-term non-renal complications of childhood nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is the most common glomerular childhood disease. A body of literature has described the long-term renal prognosis of childhood-onset idiopathic NS. However, the nonrenal outcomes have not been studied as much.

AIM

We aimed to discuss the long-term non-renal outcomes of childhood NS, highlighting studies with a follow-up period of more than 10 years.

RESULTS

We reviewed the literature and found that a number of immunosuppressive agents have stopped inflammation, stabilised the podocyte cytoskeleton and reduce proteinuria. However, prolonged treatment has frequently been associated with a high risk of renal and non-renal complications in patients with a complicated disease course, defined as frequent relapses or steroid dependency. Non-renal complications may include impaired longitudinal growth and pubertal development, undesirable fertility outcomes, ocular complications, bone mineral diseases and potential malignancies.

CONCLUSION

This review discusses and summarises the non-renal outcomes of idiopathic childhood NS.

Therapeutic Response to Corticosteroids Remains a Valid Approach to Initial Management of Children With Idiopathic Nephrotic Syndrome

Complete remission of idiopathic nephrotic syndrome (INS) in response to corticosteroids has been widely adopted as an indicator of satisfactory long-term outcomes in pediatric patients. The approach was based on the results of studies conducted in the 1960s and 1970s. The studies found that corticosteroid-responsive minimal change disease (MCD) was the most frequent diagnosis in INS patients. In more recent years, studies have reported increased frequency of focal segmental glomerulosclerosis (FSGS) and primary corticosteroid resistance without a corresponding increase of FSGS. It became unclear whether withholding kidney biopsy before treatment with corticosteroids is still the best management practice. We performed a retrospective chart review at the UPMC Children's Hospital of Pittsburgh and identified patients who were referred for evaluation of edema or proteinuria between 2002 and 2014. We identified 114 pediatric patients with INS who were treated initially with a corticosteroid (prednisone or prednisolone) 2 mg/kg (max 60 mg)/day for 4-6 weeks followed by 2 mg/kg (max 60 mg) every other day for 4-6 weeks and had not received a corticosteroid-sparing agent before completing at least 8 weeks of the initial therapy. Corticosteroid resistance in pediatric INS patients was independently associated with the black race, older age at presentation (>8 years), and female sex. The majority of blacks who were resistant to corticosteroids had a tissue diagnosis of MCD. Among the whites who were steroid-resistant, MCD and FSGS were diagnosed in similar proportions of cases. Thus, the tissue diagnosis in could not predict the response to corticosteroids. Nineteen percent of whites with FSGS were steroid-sensitive and none of the blacks with FSGS responded to corticosteroids. These data suggest that the histologic diagnosis of FSGS could not rule out response to corticosteroids, at least, in the white patient population. In summary, our data demonstrate that at this time, the therapeutic response to corticosteroids continues to be a valid approach for the initial evaluation and therapy of children diagnosed with INS at our center. Future studies should evaluate the mechanisms of changing characteristics of pediatric INS. The specific role of patient demographics, ethnicity, as well as genetic and environmental factors could be evaluated by a prospective, multicenter study.

Prediction of Short- and Long-Term Outcomes in Childhood Nephrotic Syndrome

Introduction

It is unknown whether steroid sensitivity and other putative risk factors collected at baseline can predict the disease course of idiopathic nephrotic syndrome in childhood. We determined whether demographic, clinical, and family reported factors at presentation can predict outcomes in idiopathic nephrotic syndrome.

Methods

An observational cohort of 631 children aged 1 to 18 years diagnosed with idiopathic nephrotic syndrome between 1993 and 2016 were followed up until clinic discharge, 18 years of age, end-stage kidney disease (ESKD), or the last clinic visit. Baseline characteristics were age, sex, ethnicity, and initial steroid sensitivity. Of these, 287 (38%) children also reported any family history of kidney disease, preceding infection, microscopic hematuria, and history of asthma/allergies. The outcomes were complete remission after initial steroid course, need for a second-line agent, frequently relapsing disease, and long-term remission. The discriminatory power of the models was described using the c-statistic.

Results

Overall, 25.7% of children had no further disease after their initial steroid course. In addition, 31.2% developed frequently relapsing disease; however, 77.7% were disease-free at 18 years of age. Furthermore, 1% of children progressed to ESKD. Logistic regression modeling using the different baseline exposures did not significantly improve the prediction of outcomes relative to the observed frequencies (maximum c-statistic, 0.63; 95% confidence interval [CI], 0.59–0.67). The addition of steroid sensitivity did not improve outcome prediction of long-term outcomes (c-statistic, 0.63; 95% CI, 0.54–0.70).

Conclusions

Demographic, clinical, and family reported characteristics, specifically steroid sensitivity, are not useful in predicting relapse rates or long-term remission in idiopathic nephrotic syndrome. Further studies are needed to address factors that contribute to long-term health.

Long-term outcome of Japanese children with complicated minimal change nephrotic syndrome treated with mycophenolate mofetil after cyclosporine

BACKGROUND

Although recent studies have shown that more than half of children with steroid-dependent nephrotic syndrome (SDNS) may continue to have active disease beyond childhood, the long-term outcome in this cohort treated with mycophenolate mofetil (MMF) after cyclosporine remains unknown, particularly in adulthood.

METHODS

We conducted a retrospective study of 44 adult patients (median age, 22.3 years) who received MMF for complicated SDNS (median age at MMF initiation, 13.3 years) at a single center. Complicated SDNS was defined as the case continuing to relapse after cyclosporine (CsA) treatment. When patients experienced relapses despite MMF initiation, they additionally received a rituximab infusion. The primary endpoint was the probability of achieving treatment-free remission for > 2 years.

RESULTS

Prior to MMF initiation, all patients received CsA for a median of 46 months and 19 received the 12-week cyclophosphamide. After switching from CsA to MMF, only four patients did not relapse during a median follow-up period of 9.6 years. At the last visit, only 15 of the 44 patients achieved treatment-free sustained remission. Multivariate analysis revealed that young age (< 6 years) at onset of nephrotic syndrome (odds ratio, 11.3) and the experience of steroid dependency during initial CsA treatment (odds ratio, 29.8) were the independent risk factors of active disease into adulthood after MMF initiation.

CONCLUSIONS

Although none developed renal insufficiency and severe adverse effects of therapy, the introduction of MMF after CsA treatment may not be necessarily associated with improved long-term outcome of children with complicated SDNS.

Sixteen-week versus standard eight-week prednisolone therapy for childhood nephrotic syndrome: the PREDNOS RCT

BACKGROUND

The optimal corticosteroid regimen for treating the presenting episode of steroid-sensitive nephrotic syndrome (SSNS) remains uncertain. Most UK centres use an 8-week regimen, despite previous systematic reviews indicating that longer regimens reduce the risk of relapse and frequently relapsing nephrotic syndrome (FRNS).

OBJECTIVES

The primary objective was to determine whether or not an extended 16-week course of prednisolone increases the time to first relapse. The secondary objectives were to compare the relapse rate, FRNS and steroid-dependent nephrotic syndrome (SDNS) rates, requirement for alternative immunosuppressive agents and corticosteroid-related adverse events (AEs), including adverse behaviour and costs.

DESIGN

Randomised double-blind parallel-group placebo-controlled trial, including a cost-effectiveness analysis.

SETTING

One hundred and twenty-five UK paediatric departments.

PARTICIPANTS

Two hundred and thirty-seven children presenting with a first episode of SSNS. Participants aged between 1 and 15 years were randomised (1 : 1) according to a minimisation algorithm to ensure balance of ethnicity (South Asian, white or other) and age (≤ 5 or ≥ 6 years).

INTERVENTIONS

The control group (n = 118) received standard course (SC) prednisolone therapy: 60 mg/m²/day of prednisolone in weeks 1-4, 40 mg/m² of prednisolone on alternate days in weeks 5-8 and matching placebo on alternate days in weeks 9-18 (total 2240 mg/m²). The intervention group (n = 119) received extended course (EC) prednisolone therapy: 60 mg/m²/day of prednisolone in weeks 1-4; started at 60 mg/m² of prednisolone on alternate days in weeks 5-16, tapering by 10 mg/m² every 2 weeks (total 3150 mg/m²).

MAIN OUTCOME MEASURES

The primary outcome measure was time to first relapse [Albustix^® (Siemens Healthcare Limited, Frimley, UK)-positive proteinuria +++ or greater for 3 consecutive days or the presence of generalised oedema plus +++ proteinuria]. The secondary outcome measures were relapse rate, incidence of FRNS and SDNS, other immunosuppressive therapy use, rates of serious adverse events (SAEs) and AEs and the incidence of behavioural change [using Achenbach Child Behaviour Checklist (ACBC)]. A comprehensive cost-effectiveness analysis was performed. The analysis was by intention to treat. Participants were followed for a minimum of 24 months.

RESULTS

There was no significant difference in time to first relapse between the SC and EC groups (hazard ratio 0.87, 95% confidence interval 0.65 to 1.17; log-rank p = 0.3). There were also no differences in the incidence of FRNS (SC 50% vs. EC 53%; p = 0.7), SDNS (44% vs. 42%; p = 0.8) or requirement for other immunosuppressive therapy (56% vs. 54%; p = 0.8). The total prednisolone dose received following completion of study medication was 5475 mg vs. 6674 mg (p = 0.07). SAE rates were not significantly different (25% vs. 17%; p = 0.1) and neither were AEs, except poor behaviour (yes/no), which was less frequent with EC treatment. There were no differences in ACBC scores. EC therapy was associated with a mean increase in generic health benefit [0.0162 additional quality-adjusted life-years (QALYs)] and cost savings (£4369 vs. £2696).

LIMITATIONS

Study drug formulation may have prevented some younger children who were unable to swallow whole or crushed tablets from participating.

CONCLUSIONS

This trial has not shown any clinical benefit for EC prednisolone therapy in UK children. The cost-effectiveness analysis suggested that EC therapy may be cheaper, with the possibility of a small QALY benefit.

FUTURE WORK

Studies investigating EC versus SC therapy in younger children and further cost-effectiveness analyses are warranted.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16645249 and EudraCT 2010-022489-29.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 26. See the NIHR Journals Library website for further project information.

Five-year outcome of children with idiopathic nephrotic syndrome: the NEPHROVIR population-based cohort study

BACKGROUND

The optimal therapeutic regimen for children at onset of idiopathic nephrotic syndrome (INS) is still under debate. A better knowledge of the disease's course is necessary to design more appropriate and/or personalized treatment protocols.

METHODS

We report the 5-year outcome of patients included from December 2007 to May 2010 in the prospective multicentric and multiethnic population-based NEPHROVIR study. Patients were treated at onset according to the French steroid protocol (3990 mg/m², 18 weeks). Data were collected at 5 years or last follow-up.

RESULTS

Out of the 188 children with nephrotic syndrome (121 boys, 67 girls; median age 4.1 years), 174 (93%) were steroid-sensitive. Six percent of steroid-sensitive patients required intravenous steroid pulses to get into remission. Relapse-free rate for steroid-sensitive patients was 21% (36/174) at last follow-up (median 72 months). A first relapse occurred in138 steroid sensitive patients (79%) with a median time of 8.3 months (IQ 3.4-11.3). Out of the 138 relapsers, 43 were frequent relapsers. Age at onset below 4 years was the only predictive factor of relapse, while gender, ethnicity, and delay to first remission were not. At 96 months of follow-up, 83% of frequent relapsers were still under steroids and/or immunosuppressive drugs.

CONCLUSIONS

The treatment of the first flare deserves major improvements in order to reduce the prevalence of relapsers and the subsequent long-lasting exposure to steroids and immunosuppression.

Childhood onset steroid-sensitive nephrotic syndrome continues into adulthood

BACKGROUND

Childhood steroid-sensitive nephrotic syndrome (SSNS) has previously been assumed to be a disease of childhood. This has been challenged by few studies reporting that some patients with childhood SSNS may continue to relapse into adulthood. The aim of this study was to investigate the long-term outcome of childhood SSNS presenting data from an unselected well-defined cohort of Danish patients.

METHODS

We conducted a retrospective study of the clinical outcome from a population of patients consecutively admitted to the pediatric departments in the central and northern region of Denmark from 1998 to 2015. Patients were followed until August 2017. Data were collected from the patient's medical records.

RESULTS

Long-term outcome was studied in 39 adult patients with childhood onset SSNS. A total of 31% (12/39) had active disease in adulthood. Univariate analysis showed that more severe forms of SSNS (e.g., steroid dependent/frequent relapsing (SD/FR) nephrotic syndrome) in childhood were associated with active disease in adulthood. Comparing adult patients with SD/FR showed a significantly higher number of relapses/patient/year from late childhood and adolescence in the group with active disease vs. non-active disease (1.06 (95%CI: 0.32-1.81) vs. 0.19 (95%CI: 0.06-0.31, p = 0.005).

CONCLUSION

In general, one third of all patients with SSNS during childhood continue to have active disease during early adulthood, in particular patients with SD/FR continue to suffer from active disease. The present data illustrates that SSNS is not just a disease of childhood but persists in adulthood in a significant number of patients.

Clinical course & management of childhood nephrotic syndrome in Germany: a large epidemiological ESPED study

Background

Nephrotic syndrome (NS) is one of the most frequent occurring chronic kidney diseases in childhood, despite its rarely occurrence in the general population. Detailed information about clinical data of NS (e.g. average length of stay, complications) as well as of secondary nephrotic syndrome (SNS) is not well known.

Methods

A nationwide ESPED follow-up study presenting the clinical course and management of children with NS in Germany.

Results

In course of 2 years, 347 children developed the first onset of NS, hereof 326 patients (93.9%) had a primary NS, and 19 patients had a SNS (missing data in 2 cases), the majority due to a Henoch-Schönlein Purpura. Patients with steroid-resistant NS (SRNS) stayed significantly longer in hospital than children with steroid-sensitive NS (25.2 vs. 13.3 d, p <  0.001). Patients with bacterial/viral infections stayed longer in hospital (24.9 d/19.5d) than children without an infection (14.2 d/14.9 d; p <  0.001; p = 0.016). Additionally, children with urinary tract infections (UTI) (p < 0,001), arterial hypertension (AH) (p < 0.001) and acute renal failure (ARF) (p < 0,001) stayed significantly longer in hospital.

Patients with SRNS had frequent complications (p = 0.004), such as bacterial infections (p = 0.013), AH (p < 0.001), UTI (p < 0.001) and ARF (p = 0.007). Children with a focal segmental glomerulosclerosis (FSGS) had significantly more complications (p = 0.04); specifically bacterial infections (p = 0.01), UTI (p = 0.003) and AH (p < 0,001). Steroid-resistance was more common in patients with UTI (p < 0.001) and in patients with ARF (p = 0.007). Furthermore, steroid-resistance (p < 0.001) and FSGS (p < 0.001) were more common in patients with AH.

Conclusions

This nationwide, largest German study presents results on the clinical course of children with NS considering a diverse range of complications that can occur with NS. The establishment of a region-wide and international pediatric NS register would be useful to conduct further diagnostic and therapy studies with the aim to reduce the complication rate and to improve the prognosis of NS, and to compare the data with international cohorts.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1233-1) contains supplementary material, which is available to authorized users.

The long-term outcome of childhood nephrotic syndrome in Germany: a cross-sectional study

BACKGROUND

Long-term outcomes of children with nephrotic syndrome have not been well described in the literature.

METHODS

Cross-sectional study data analysis of n = 43 patients with steroid-sensitive (SSNS) and n = 7 patients with steroid-resistant (SRNS) nephrotic syndrome were retrospectively collected; patients were clinically examined at a follow-up visit (FUV), on average 30 years after onset, there was the longest follow-up period to date.

RESULTS

The mean age at FUV was 33.6 years (14.4-50.8 years, n = 41). The mean age of patients with SSNS at onset was 4.7 years (median 3.8 years (1.2-14.5 years), the mean number of relapses was 5.8 (0 to 29 relapses). Seven patients (16.3%) had no relapses. Eleven patients were "frequent relapsers" (25.6%) and four patients still had relapses beyond the age of 18 years. Except of cataracts and arterial hypertension, there were no negative long-term outcomes and only one patient was using immunosuppressant therapy at FUV. 55% of patients suffered from allergies and 47.5% had hypercholesterolemia. Two patients suffered a heart attack in adulthood. A younger age at onset (< 4 years) was a risk factor for frequent relapses. An early relapse (within 6 months after onset) was a risk factor and a low birth weight was not a significant risk factor for a complicated NS course. The mean age of patients with SRNS at onset was 4.6 ± 4.4 years and 27.5 ± 9.9 years at FUV. Three patients received kidney transplantations.

CONCLUSIONS

The positive long-term prognosis of SSNS can reduce the concern of parents about the probability of the child developing a chronic renal disease during the clinical course after onset.

Bayesian treatment comparison using parametric mixture priors computed from elicited histograms

A Bayesian methodology is proposed for constructing a parametric prior on two treatment effect parameters, based on graphical information elicited from a group of expert physicians. The motivating application is a 70-patient randomized trial to compare two treatments for idiopathic nephrotic syndrome in children. The methodology relies on histograms of the treatment parameters constructed manually by each physician, applying the method of Johnson et al. (2010). For each physician, a marginal prior for each treatment parameter characterized by location and precision hyperparameters is fit to the elicited histogram. A bivariate prior is obtained by averaging the marginals over a latent physician effect distribution. An overall prior is constructed as a mixture of the individual physicians' priors. A simulation study evaluating several versions of the methodology is presented. A framework is given for performing a sensitivity analysis of posterior inferences to prior location and precision and illustrated based on the idiopathic nephrotic syndrome trial.

Qualitative Analysis of the Psychosocial Adaptation Process in Children with Chronic Kidney Disease: Toward Effective Support During Transition from Childhood to Adulthood

Background

Pediatric chronic renal disease only shows abnormal values in a urinalysis in the initial stage, and subjective signs and symptoms are rare. If adolescents with chronic renal disease face a disease crisis combined with the usual developmental crisis, this may cause psychosocial maladaptation. We analyzed psychosocial adaptation in Japanese children with chronic renal disease in order to identify factors influencing healthy adaptation.

Methods

Ten children and adult patients with chronic kidney disease attending Tottori University Hospital, Japan in 2016 participated in a semi-structured interview (a modified version of the grounded theory approach) comprising questions about episodes since disease onset and thoughts/feelings at onset.

Results

Twenty-four concepts extracted from the data were sorted into 5 categories. These concepts and categories were expanded on an orthogonal axis with time and self-esteem in order to establish an adaptation model for children with chronic kidney disease. Category names are as follows. (Cat. 1: Emotional impact on being informed of disease, Cat. 2: Social challenges of treatment and resulting identity diffusion, Cat. 3: Emotional conflict on school return, Cat. 4: Resilience and related factors, Cat. 5: Re-establishment of identity).

Conclusion

Since pediatric chronic renal disease has few manifestations, it is difficult for patients to accept. Children facing a chronic disease crisis plus adolescent developmental crisis may show identity diffusion. In order for children to re-establish their identity and adapt to society, factors supporting resilience are important. Key factors include school life, interactions with friends, counseling by adult mentors and family acceptance. Healthcare professionals need to provide age-appropriate information on renal disease and support patients.