Childhood onset steroid-sensitive nephrotic syndrome continues into adulthood

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.

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.

Is kidney biopsy necessary in children with idiopathic nephrotic syndrome?

AIM

To investigate the need, in the Northern European setting, to perform kidney biopsy in children with steroid-sensitive nephrotic syndrome.

METHODS

In this retrospective study 124 individuals aged 1-18 years with idiopathic nephrotic syndrome, followed in the paediatric hospitals in southern Sweden from 1999 to 2018, were included.

RESULTS

There was a median follow-up time of 6.5 (0.2-16.8) years. The majority (92%) of children were steroid-sensitive and of them, 60.5% were frequently relapsing or steroid-dependent. Microscopic haematuria was found at onset in 81.1% and hypertension in 8.7%. At least one kidney biopsy was performed in 93 (75%). The most common indication was a steroid-dependent or relapsing course (58.4%). One of 79 steroid-sensitive children had another histological diagnosis than minimal change nephropathy 1.3%, 95% confidence interval (0.002, 0.068). Bleeding occurred after eight biopsies (6.6%). Twenty individuals (30.7%) were transferred to adult units, 18 still on immunosuppression.

CONCLUSION

We have in our cohort of unselected children with idiopathic nephrotic syndrome confirmed that a kidney biopsy rarely gives important medical information in steroid-sensitive children without any other complicating factor and that the liberal policy of kidney biopsy in the Nordic countries safely can be changed.

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.

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.

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.

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.

Lipoproteins and cholesterol homeostasis in paediatric nephrotic syndrome patients

Introduction

The aim of this study was to investigate lipoprotein particle distributions and the likelihood of achieving cholesterol homeostasis in the remission phase of nephrotic syndrome (NS) in paediatric patients. We hypothesized that lipoprotein particle distributions moved toward less atherogenic profile and that cholesterol homeostasis was achieved.

Materials and methods

Thirty-three children, 2 to 9 years old with NS were recruited. Blood sampling took place both in the acute phase and during remission. Serum low-density lipoprotein particles (LDL) and high-density lipoprotein particles (HDL) were separated using non-denaturing polyacrylamide gradient gel (3-31%) electrophoresis. Serum non-cholesterols sterols (NCSs), desmosterol, lathosterol, 7-dehydrocholesterol (7-DHC), campesterol and β-sitosterol were measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

Results

All patients had desirable serum HDL cholesterol concentrations during remission. The dominant lipoprotein diameters and LDL subclass distribution did not change significantly during follow-up. In contrast, HDL lipoprotein particle distribution shifted towards larger particles. The absolute concentration of desmosterol was significantly lower during remission (P = 0.023). β-sitosterol concentration markedly increased during remission (P = 0.005). Desmosterol/β-sitosterol (P < 0.001) and 7-DHC/β-sitosterol (P = 0.005) ratios significantly declined during disease remission.

Conclusions

Favourable changes in the serum lipid profiles, HDL particle subclass distribution and cholesterol metabolism in paediatric patients with NS during remission took place. For the first time, we found that cholesterol homeostasis changed in favour of increased cholesterol absorption during disease remission. Nevertheless, complete cholesterol homeostasis was not achieved during disease remission.

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.

Serum immunoglobulin E level in children with nephrotic syndrome

Background and objective: The most supported theory for Nephrotic Syndrome (NS) etiology is that it is immune-mediated. This study aims to assess the level of serum IgE in children with Steroid Sensitive NS (SSNS) at relapse and remission, and its correlation with the presence of atopy. Methods: This cross-sectional study was approved by the Department of Pediatrics, College of Medicine, Al-Nahrain University (Baghdad, Iraq) and conducted at Al-Imamain Al-Kadhimain Medical City (Baghdad, Iraq), and Child Central Teaching Hospital (Baghdad, Iraq), and included 31 children SSNS. The data collected was: age, sex, residency, onset of NS, response to steroid, frequency of relapses, and the history of atopy of the patient and his relatives. Serum IgE level was measured during relapse for all patients and for 9 patients while in remission. Results: Atopy was present in 18 (58.06%) of patients. The median serum IgE level was 295.5 IU/mL (range 54-2864 IU/mL) in relapse, which is significantly higher (P-value =0.006) than in remission 228.5 IU/mL (range 62-2069 IU/mL). Median serum level of IgE in patients with atopy was 290.5 IU/mL (range 24-2864 IU/mL) which was higher than that of patients without atopy (median 231 IU/mL, range 23-1314 IU/m) (P-value = 0.029). Patients required longer period to respond to steroid therapy (>10 days) had a significantly higher median of IgE (341 IU/mL) than those who required <10 days to respond (161 IU/mL) (P-value =0.045). Conclusions: Increased IgE level is documented during relapse and in atopic children with SSNS. Longer duration to respond to steroid therapy is associated significantly with higher serum IgE during relapse.

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.