Steroid-resistant Nephrotic Syndrome Patients Research Articles

#369 Anti-nephrin antibodies identify patients with steroid-resistant nephrotic syndrome responsive to immunosuppressants

Abstract Background and Aims The presence of circulating anti-nephrin antibodies has been recently reported in some patients with nephrotic syndrome (NS) and minimal change lesions, implying an autoimmune podocytopathy subset. We hypothesized that the presence of anti-nephrin antibodies would identify a subset of patients with steroid resistant NS (SRNS) and explain their response to second-line immunosuppressant therapy before and after kidney transplantation. Method We evaluated 31 patients with available kidney biopsy samples of our previously described prospective cohort of SRNS patients, genetically tested with whole exome sequencing at Meyer University Hospital IRCCS. By using high-resolution confocal microscopy, we assessed the co-localization between IgG and nephrin staining on kidney biopsy. To unequivocally establish anti-nephrin specificity of the deposited IgG, we performed super-resolution STimulated Emission Depletion (STED) microscopy. Results We observed anti-nephrin antibodies in 35.5% of patients with SRNS irrespective of podocytopathy lesion pattern. Antibody-positive (Antibody+) patients had a more severe NS at onset and better response to immunosuppression therapy compared to antibody-negative (Antibody-) patients. Only 1/11 Antibody+ patient developed chronic kidney disease compared to 9/20 Antibody- patients over a 10-year period. The single multidrug-resistant Antibody+ patient reached kidney failure had a pathogenic variant in the autosomal dominant-transmitted LMX1B. The patient experienced recurrence of NS after kidney transplantation with a positive response to plasmapheresis and rituximab. The allograft biopsy confirmed the presence of anti-nephrin antibodies. Conclusion The observed variability in patients with SRNS, influenced by a combination of genetic factors and nephrin autoimmunity, likely contributes to the diverse long-term outcomes and variations in responses to second-line immunosuppressant therapy.

Clinical Profile of Pediatric Patients with Steroid-resistant Nephrotic Syndrome Treated by Cyclophosphamide, Cyclosporin A, Mycophenolate Mofetile and Tacrolimus in Hasan Sadikin General Hospital

BackgroundSteroid-resistant nephrotic syndrome is a major cause of chronic kidney disease in children and adolescents. These diseases require appropriate management, while in some developing countries, the availability of agents recommended by international guidelines is very limited.Research objectivesTo determine and describe the patient profiles of pediatric Steroid Resistant Nephrotic Syndrome (SRNS) that use Cyclophosphamide(CPA), Cyclosporine(CyA), Tacrolimus, and Mycofenolat Mofetil (MMF) in Dr. Hasan Sadikin Hospital (RSHS), Bandung as a tertiary hospital in West Java, Indonesia.Methods and materialsThis research used a retrospective study with cross-sectional study design, total sampling method and medical record of pediatric (1-18 years old) patients from January 1st 2017–September 31st 2019 who were diagnosed as SRNS .Results : From 99 subjects that belonged to inclusion criteria, 35.4% pediatric SRNS patients were in the age group 6-10 years and 60.6% were males. Laboratorium profiles showed among all population, ureum <100 mg/dL were found as high as 97%, creatinine 0.3-1.0 mg/dL (71.7%) albumin >2,5 gr/dL (51.5%), negative hematuria (68.7%) , protein dipstick < 3 (50.5%), and LFG > 90 mL/min/1.73 m2 (79.8%).. The patients generally had use CPA (87.9%) and remission <6 month (51.5%).Conclusion: Profiles of pediatric patients are important to diagnose and prognose SRNS. By using these approaches, it is feasible to access and detect the most effective treatment for SRNS.

Mutation of NPHS1, NPHS2, WT1, LAMB2, COL4A5 and other genes in children with idiopathic steroid resistant nephrotic syndrome

Background: Many children with idiopathic steroid resistant nephrotic syndrome have been reported worldwide due to mutation of NPHS1, NPHS2, WT1 and LAMB2 genes. This study aimed to determine the frequency of mutation of NPHS1, NPHS2, WT1, LAMB2, COL4A5 and other genes and their association with renal histopathological patterns of idiopathic steroid resistant nephrotic syndrome patients. Methods: This cross-sectional study was conducted on 25 patients with idiopathic steroid resistant nephrotic aged 1-17 years in the Department of Paediatric Nephrology, Bangabandhu Sheikh Mujib Medical University, Bangladesh, from July 2017 to June 2018. Next Generation Sequencing and mutation analysis were performed after DNA extraction from patients' venous blood lymphocytes. Histopathological study of renal tissue was done among 17 patients. Results: A little more than half (56%) of the patients were male. The mean age at the initial attack of nephrotic syndrome was 94.2 months. They mostly had minimal change disease (41%) and IgA nephropathy (12%). One subject had the NPHS2 gene mutation, histopathologically diffuse mesangial proliferative glomerulonephritis, and clinically stage-4 chronic kidney disease. Another subject had the COL4A5 gene mutation and focal segmental glomerulosclerosis. Both were male and had no familial renal disease, consanguinity, or hematuria. Conclusion: Children with idiopathic steroid resistant nephrotic syndrome showed NPHS2 and COL4A5 gene mutations. Histopathologically, they showed diffuse mesangial proliferative glomerulonephritis and focal segmental glomerulosclerosis.

Tumor necrosis factor alpha gene polymorphism affects the pattern of idiopathic nephrotic syndrome in Kuwaiti Arab children.

TNF-α is a pro-inflammatory cytokine that has been implicated in many inflammatory diseases, but its association with idiopathic nephrotic syndrome (INS) is poorly understood. This study looked for an association of TNF-α gene polymorphisms with INS, as well as its effect on steroid responsiveness among Kuwaiti Arab children. Genotypes of the TNF-a gene polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism in 151 INS Kuwaiti Arab patients and 64 age and sex-matched controls. Clinical data of all subjects were reviewed. The heterozygous AG genotype was detected in 8.6% of INS patients compared 23.4% of the controls (p < 0.01). Comparing steroid responsiveness, AA genotype was significantly more common in steroid-sensitive nephrotic syndrome (SSNS) cases than steroid-resistant nephrotic syndrome (SRNS) patients (p = 0.001). However, AG genotype was significantly more common in SRNS patients compared to the SSNS cases (p = 0.001). No difference was found between these two subgroups in the GG genotype frequency. AG genotype of TNF-a gene polymorphisms may be considered a suitable marker for INS disease among Kuwaiti children. Both AA and AG genotypes may be useful in predicting steroid responsiveness among these cases of Arab ethnicity. The findings might open the era for the use of genetic markers in the early treatment of NS.

Monogenic Causes Identified in 23.68% of Children with Steroid-Resistant Nephrotic Syndrome: A Single-Centre Study

Introduction: Steroid-resistant nephrotic syndrome (SRNS) is the second most common cause of end-stage kidney disease in children, mostly associated with focal segmental glomerulosclerosis (FSGS). Advances in genomic science have enabled the identification of causative variants in 20–30% of SRNS patients. Methods: We used whole exome sequencing to explore the genetic causes of SRNS in children. Totally, 101 patients with SRNS and 13 patients with nephrotic proteinuria and FSGS were retrospectively enrolled in our hospital between 2018 and 2022. For the known monogenic causes analysis, we generated a known SRNS gene list of 71 genes through reviewing the OMIM database and literature. Results: Causative variants were identified in 23.68% of our cohort, and the most frequently mutated genes in our cohort were WT1 (7/27), NPHS1 (3/27), ADCK4 (3/27), and ANLN (2/27). Five patients carried variants in phenocopy genes, including MYH9, MAFB, TTC21B, AGRN, and FAT4. The variant detection rate was the highest in the two subtype groups with congenital nephrotic syndrome and syndromic SRNS. In total, 68.75% of variants we identified were novel and have not been previously reported in the literature. Conclusion: Comprehensive genetic analysis is key to realizing the clinical benefits of a genetic diagnosis. We suggest that all children with SRNS undergo genetic testing, especially those with early-onset and extrarenal phenotypes.

Doppler Evaluation of Renal Vessels in Pediatric Patients with Relapse and Remission in Different Categories of Nephrotic Syndrome

Aim: To study resistivity &amp; pulsatility indices in the interlobar arteries of kidneys in patients with idiopathic nephrotic syndrome and evaluate their response to steroids Method: The prospective case-control study was carried out in 100 patients, aged 2 years - 15 years of nephrotic syndrome and divided into 5 groups depending upon their response to steroids. Twenty-five age-matched controls were included for comparison. The abdominal ultrasonography and Doppler examinations were performed for patients of each group and for the controls. Result: The mean Resistivity Index (RI) and Pulsatility Index (PI) of the interlobar arteries were calculated for the five subgroups of nephrotic syndrome patients and for the controls. There was a significant difference in mean RI in all the evaluated arteries between the 6 groups. No significant difference was noted in the pulsatality indices of the kidney of the cases of nephrotic syndrome when compared to controls. Conclusion: Steroid-resistant nephrotic syndrome patients show a statistically significant difference in RI and not a statistically significant difference in PI Doppler parameters when groups of patients compared to controls. These parameters may be used to predict the response to steroids.

Comparison of Urinary Beta-2 Microglobulin Levels in Children with SSNS and Calcineurin Inhibitor-Treated SRNS.

While the utility of beta-2 microglobulin (β2M) has been explored in various renal conditions to identify tubulointerstitial damage, it has not been adequately studied in nephrotic syndrome. The primary objective of the study was to compare urinary β2M levels in children with steroid-sensitive nephrotic syndrome (SSNS) and steroid-resistant nephrotic syndrome (SRNS) in disease remission. This cross-sectional study was done at a tertiary care hospital between April 2019 and March 2020. Sixty children (2-18 years) with SSNS and SRNS (30 in each group) in remission were enrolled. SRNS patients were included after ≥1 year of treatment with calcineurin inhibitors (CNIs). Biochemical investigations were done to confirm remission; spot samples for urinary β2M were collected and estimation was done by an enzyme-linked immunosorbent assay (ELISA)-based kit. Of the 60 children, 63% were boys. The median (interquartile range [IQR]) age at enrollment for SSNS and SRNS patients was 7 (4.1-9) and 11 (8.3-12) years, respectively. Urinary β2M levels were significantly higher in SRNS patients compared to SSNS patients (2.6 vs. 0.75 mg/ml, P < 0.0001). Patients who received cyclosporine for >2 years had higher median urinary β2M levels compared to those who received it for a shorter period (2.63 vs. 1.83 mg/ml, P = 0.03). Median β2M levels were higher in focal segmental glomerulosclerosis than minimal change disease (3.5 vs. 2.5 mg/ml). Urinary β2M levels were higher in SRNS compared to SSNS disease in remission, and β2M levels correlated well with CNI use of >2 years. It appears to be a promising noninvasive tool to identify early tubular damage and progression in patients with nephrotic syndrome, especially SRNS.

Long-term outcomes in children with idiopathic nephrotic syndrome: a single center experience

Purpose: Idiopathic nephrotic syndrome (INS) is a common glomerular disease observed in children. Depending on their response to steroids, patients can be classified either as having steroid-sensitive nephrotic syndrome (SSNS) or steroid-resistant nephrotic syndrome (SRNS). Whereas SSNS patients respond favorably to steroid treatment and achieve a complete remission with normal renal functions, SRNS patients do not, and are at high risk of developing end-stage renal diseases (ESRD). The aim of this study was to analyze the long-term outcomes of patients with INS.&#x0D; Materials and Methods: In our medical center, records of children diagnosed with INS were evaluated. Demographic information, laboratory results, response to treatment, and clinical progression were analyzed.&#x0D; Result: Ninety-one children (64% male) with a mean age of 11.1±4.1 years (3.5-18) were included in the patient cohort, with a mean age of diagnosis of 5.2±3.8 years (1-16.2) and a mean follow-up period of 5.7±2.8 years (2-12). Sixty-eight (75%) patients had SSNS, and 23 (25%) patients had SRNS. Among the SSNS patients, 18 (31%) were steroid-dependent, 12 (20%) were frequently relapsing, and 29 (49%) were infrequently relapsing. Renal biopsy was performed on 29 (32%) patients, 59% had focal segmental glomerulosclerosis. The complete remission rate was 94% for all patients, with 100% for SSNS and 74% for SRNS. ESRD was developed for 9% of patients with SRNS.&#x0D; Conclusion: The response to steroid treatment serves as a valuable prognostic indicator for INS as it plays a pivotal role in mitigating the risk of progression toward end-stage renal failure.

Genetic analysis and outcomes of Omani children with steroid-resistant nephrotic syndrome.

Nephrotic syndrome (NS) is one of the most common kidney disorders seen by pediatric nephrologists and is defined by the presence of heavy proteinuria (>3.5 g/24 h), hypoalbuminemia (<3.5 g/dL), edema, and hyperlipidemia. Most children with NS are steroid-responsive and have a good prognosis following treatment with prednisolone. However, 10%-20% of them have steroid-resistant nephrotic syndrome (SRNS) and fail to respond to treatment. A significant proportion of these children progress to kidney failure. This retrospective study aimed to determine the underlying genetic causes of SRNS among Omani children below 13 years old, over a 15-year period and included 77 children from 50 different families. We used targeted Sanger sequencing combined with next-generation sequencing approaches to perform molecular diagnostics. We found a high rate of underlying genetic causes of SRNS in 61 (79.2%) children with pathogenic variants in the associated genes. Most of these genetically solved SRNS patients were born to consanguineous parents and variants were in the homozygous state. Pathogenic variants in NPHS2 were the most common cause of SRNS in our study seen in 37 (48.05%) cases. Pathogenic variants in NPHS1 were also seen in 16 cases, especially in infants with congenital nephrotic syndrome (CNS). Other genetic causes identified included pathogenic variants in LAMB2, PLCE1, MYO1E, and NUP93. NPHS2 and NPHS1 genetic variants were the most common inherited causes of SRNS in Omani children. However, patients with variants in several other SRNS causative genes were also identified. We recommend screening for all genes responsible for SRNS in all children who present with this phenotype, which will assist in clinical management decisions and genetic counseling for the affected families.

Urinary Apolipoprotein A1 and Neutrophil Gelatinase-associated Lipocalin in Children with Idiopathic Nephrotic Syndrome

Urinary biomarkers are a promising diagnostic modality whose role was explored in nephrotic syndrome (NS). We estimated urinary apolipoprotein A1 (Apo A1) and neutrophil gelatinase-associated lipocalin (NGAL) in children with first-episode NS (FENS) and controls with a longitudinal follow-up to see the serial changes during remission. The study groups comprised 35 children with FENS and an equal number of age- and sex-matched controls. Patients were followed up at regular intervals, and 32 patients were classified as having steroid-sensitive NS (SSNS) and 3 as having steroid-resistant NS (SRNS). The mean follow-up period was 8.7 ± 4.2 months. Three patients in the SSNS group were labeled as having frequent relapses or steroid-dependent disease during follow-up. Of the three children with SRNS, two had minimal changes in the disease and one had idiopathic membranous nephropathy. The levels of Apo A1:creatinine, NGAL:creatinine, and spot urinary protein:urinary creatinine ratios were significantly higher in children with FENS compared with controls. The levels of the urine biomarkers decreased significantly at subsequent follow-up with remission. The Apo A1 and NGAL levels in SSNS patients were significantly high compared with both the controls and FENS patients. Urinary Apo A1 levels in SRNS patients were lower at initial presentation. This longitudinal study revealed changes in the urinary Apo A1 and NGAL in NS over the course of the disease.

Rituximab treatment in children with difficult-to-treat nephrotic syndrome

Purpose: Rituximab (RTX) has been offered as rescue therapy for patients with difficult-to-treat nephrotic syndrome (frequent relapsing, steroid-dependent and steroid resistant). We aimed to assess the efficacy and long-term outcomes of RTX treatment in children with difficult nephrotic syndrome and shared our experiences&#x0D; Materials and Methods: Medical records of children with difficult nephrotic syndrome who were treated with RTX were retrospectively evaluated. The relapse-free survival rate at 12 month and monitoring of B-cell depletion were assessed.&#x0D; Results: In the study included 20 children of which 8 had steroid-dependent (SDNS), 6 had frequent relapsing (FRNS), and 6 had steroid-resistant nephrotic syndrome (SRNS). The median number of relapses at 1 year before and after treatment in FRNS/SDNS patients receiving RTX treatment were compared. The median number of relapses decreased from 2 (1-4) to 0 (0-1) times/year. The mean duration of the follow-up period after RTX treatment was 23 (12-59) months, and 8 patients developed relapse. Repeated doses of RTX were administered to 5 patients who relapsed after RTX treatment. In these patients, CD19+B cells re-emerged during remission, while depletion of memory B-cells remained. &#x0D; Conclusion: The RTX treatment prolonged the remission time in FRNS/SDNS patients, but it was ineffective in SRNS patients. It was determined that the RTX doses can be repeated to maintain remission in these patients, and the best memory B-cell counts can help in timing the repeat doses.

Proteinuria in Asymptomatic Siblings of Children with Steroid Resistant Nephrotic Syndrome: A Screening Using Urinary Dipstick.

To screen asymptomatic siblings of steroid-resistant nephrotic syndrome patients for proteinuria using the urinary dipstick method to determine the involvement of siblings in the familial and likely genetic cause of the steroid-resistant nephrotic syndrome. This cross-sectional study was performed at the outpatient department of Sindh Institute of Urology and Transplantation (SIUT) from May to July 2021. Out of 104 patients with steroid-resistant nephrotic syndrome, siblings of 66 patients were enrolled. Mean age of primary patients with steroid resistant nephrotic syndrome was 8.7±4.3 years. Most common histopathological diagnosis was focal segmental glomerulosclerosis in 25 (37.9%) children followed by minimal change disease in 17(25.8%) of them. The majority, 48 (72.7%) patients were on immunosuppressive treatment, while 4 (6.1%) had progressed to chronic kidney disease (CKD). A total of 178 siblings were recruited in the study. There were 99(55.6%) boys and 79(44.4%) girls. Their mean age was 10.67±6.2 years. Consanguinity was high in our study population i.e. 56(84%) families. Positive proteinuria on dipstick was detected in only 5(7.5%) enrolled SRNS families. One family refused further testing. Two of the five affected siblings had nephrotic range proteinuria. Renal biopsy of one of them showed membranous nephropathy while the second showed mesangiocapillary glomerulonephritis. Both had normal renal functions. The frequency of proteinuria in asymptomatic siblings of children with steroid-resistant syndrome is low in our population despite a high prevalence of consanguineous marriages. Hence, familial involvement of nephrotic syndrome is low and further genetic testing for monogenic causes is required in steroid-resistant nephrotic syndrome cases.

Whole-exome sequencing of a multicenter cohort identifies genetic changes associated with clinical phenotypes in pediatric nephrotic syndrome

Understanding the association between the genetic and clinical phenotypes in children with nephrotic syndrome (NS) of different etiologies is critical for early clinical guidance. We employed whole-exome sequencing (WES) to detect monogenic causes of NS in a multicenter cohort of 637 patients. In this study, a genetic cause was identified in 30.0% of the idiopathic steroid-resistant nephrotic syndrome (SRNS) patients. Other than congenital nephrotic syndrome (CNS), there were no significant differences in the incidence of monogenic diseases based on the age at manifestation. Causative mutations were detected in 39.5% of patients with focal segmental glomerulosclerosis (FSGS) and 9.2% of those with minimal change disease (MCD). In terms of the patterns in patients with different types of steroid resistance, a single gene mutation was identified in 34.8% of patients with primary resistance, 2.9% with secondary resistance, and 71.4% of children with multidrug resistance. Among the various intensified immunosuppressive therapies, tacrolimus (TAC) showed the highest response rate, with 49.7% of idiopathic SRNS patients achieving complete remission. Idiopathic SRNS patients with monogenic disease showed a similar multidrug resistance pattern, and only 31.4% of patients with monogenic disease achieved a partial remission on TAC. During an average 4.1-year follow-up, 21.4% of idiopathic SRNS patients with monogenic disease progressed to end-stage renal disease (ESRD). Collectively, this study provides evidence that genetic testing is necessary for presumed steroid-resistant and idiopathic SRNS patients, especially those with primary and/or multidrug resistance.

Long-Term Effects of Cyclophosphamide in Sustained Remission in Childhood Steroid-resistant Nephrotic Syndrome.

Nephrotic syndrome (NS) is a chronic renal disease that can progress into end-stage renal disease within 5 years if no remission occurs. Achieving optimal remission is important to obtain better outcomes of treating childhood steroid-resistant NS (SRNS). This study aimed to determine the survival, long-term outcomes, and factors associated with the sustained remission of SRNS patients after cyclophosphamide therapy. We retrospectively studied 33 children (24 boys) with SRNS treated with cyclophosphamide therapy over 2 years. Relapse-free survival was estimated using the Kaplan-Meier method. The determinants of long-term remission were assessed by univariate and multivariate analyses using Cox's proportional hazard models. The median age at the onset of NS was 3.0 years (range: 7 months to 14.0 years). The median age at the initiation of cyclophosphamide therapy was 5.0 years (range: 1.0-15.0 years). The mean cumulative cyclophosphamide dose was 155.61 ± 16.31 mg/kg body weight. In total, 18 of 33 (54.5%) children remained in remission for 2 years after cyclophosphamide therapy, and 10 of 15 patients who relapsed (66.67%) became steroid sensitive. Relapse-free survival after cyclophosphamide therapy was 78.8%, 69.7%, and 54.5% after 6, 12, and 24 months, respectively. Cox's proportional hazard regression identified no association between remission 2 years after cyclophosphamide therapy and other factors, such as age at the onset of SRNS, type of resistance, hypertension, hematuria, administration route of cyclophosphamide, and cumulative dose (all P >0.05). Cyclophosphamide therapy appeared to be beneficial for children with SRNS for sustaining 2-year remission with a 54.5% relapse-free survival rate.

Exploring the relevance of NUP93 variants in steroid-resistant nephrotic syndrome using next generation sequencing and a fly kidney model

BackgroundVariants in genes encoding nuclear pore complex (NPC) proteins are a newly identified cause of paediatric steroid-resistant nephrotic syndrome (SRNS). Recent reports describing NUP93 variants suggest these could be a significant cause of paediatric onset SRNS. We report NUP93 cases in the UK and demonstrate in vivo functional effects of Nup93 depletion in a fly (Drosophila melanogaster) nephrocyte model.MethodsThree hundred thirty-seven paediatric SRNS patients from the National cohort of patients with Nephrotic Syndrome (NephroS) were whole exome and/or whole genome sequenced. Patients were screened for over 70 genes known to be associated with Nephrotic Syndrome (NS). D. melanogaster Nup93 knockdown was achieved by RNA interference using nephrocyte-restricted drivers.ResultsSix novel homozygous and compound heterozygous NUP93 variants were detected in 3 sporadic and 2 familial paediatric onset SRNS characterised histologically by focal segmental glomerulosclerosis (FSGS) and progressing to kidney failure by 12 months from clinical diagnosis.Silencing of the two orthologs of human NUP93 expressed in D. melanogaster, Nup93-1, and Nup93-2 resulted in significant signal reduction of up to 82% in adult pericardial nephrocytes with concomitant disruption of NPC protein expression. Additionally, nephrocyte morphology was highly abnormal in Nup93-1 and Nup93-2 silenced flies surviving to adulthood.ConclusionWe expand the spectrum of NUP93 variants detected in paediatric onset SRNS and demonstrate its incidence within a national cohort. Silencing of either D. melanogaster Nup93 ortholog caused a severe nephrocyte phenotype, signaling an important role for the nucleoporin complex in podocyte biology.Graphical A higher resolution version of the Graphical abstract is available as Supplementary information

Identification of Nephrin gene variants in Indian children associated with Steroid sensitive and Steroid resistant nephrotic syndrome

Nephrotic syndrome (NS) remains the most frequent indication of glomerular disease in childhood. The NPHS1 gene encoding nephrin protein is one of the common mutant genes in SRNS (Steroid Resistant Nephrotic syndrome) patients. These gene mutations are more likely to progress into ESKD (end-stage kidney disease). In the present study, we investigated the pathogenesis of the NPHS1 gene in Indian patients with SSNS and SRNS. Ninety-six children have been involved in the present study in which 37 belong to Steroid Sensitive Nephrotic syndrome (SSNS), 27 belong to Steroid Resistant Nephrotic syndrome (SRNS) 32 are healthy individuals. We designed a panel of NPHS1 gene (CDS- Coding sequence) and performed Illumina sequencing (MiSeq). We found a total of 45 variants in the NPHS1 gene. In addition, we found novel pathogenic c.2441A > G and two likely pathogenic missense variants, p.Gly395Ser, p.Ser400Pro in SSNS and SRNS patients by ACMG criteria. Therefore, early diagnosis of steroid resistant nephrotic syndrome in the Indian population can be made by identifying genetic variants using a customized gene panel.

Management of Steroid-Resistant Nephrotic Syndrome in Children

Nephrotic syndrome (NS) affects 115-169 children per 100,000, with rates varying by ethnicity and location. Immune dysregulation, systemic circulating substances, or hereditary structural abnormalities of the podocyte are considered to have a role in the etiology of idiopathic NS. Following daily therapy with corticosteroids, more than 85% of children and adolescents (often aged 1 to 12 years) with idiopathic nephrotic syndrome have full proteinuria remission. Patients with steroid-resistant nephrotic syndrome (SRNS) do not demonstrate remission after four weeks of daily prednisolone therapy. The incidence of steroid-resistant nephrotic syndrome in children varies between 35 and 92 percent. A third of SRNS patients have mutations in one of the important podocyte genes. An unidentified circulating factor is most likely to blame for the remaining instances of SRNS.The aim of this article is to explore and review the genetic factors and management of steroid-resistant nephrotic syndrome. An all language literature search was conducted on MEDLINE, COCHRANE, EMBASE, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Steroid resistance”, “nephrotic syndrome”, “nephrosis” and “hypoalbuminemia”. We comprehensively reviewed the literature on the epidemiology, genetics, current treatment protocols, and management of steroid-resistant nephrotic syndrome.We found that for individuals with non-genetic SRNS, calcineurin inhibitors (cyclosporine and tacrolimus) constitute the current mainstay of treatment, with around 70% of patients achieving full or partial remission and an acceptable long-term prognosis. Patients with SRNS who do not react to calcineurin inhibitors or other immunosuppressive medications may have deterioration in kidney function and may develop end-stage renal failure. Nonspecific renal protective medicines, such as angiotensin-converting enzyme inhibitors, angiotensin 2 receptor blockers, and anti-lipid medications, slow the course of the illness. Recurrent focal segmental glomerulosclerosis in the allograft affects around a third of individuals who get a kidney transplant, and it frequently responds to a combination of plasma exchange, rituximab, and increased immunosuppression. Despite the fact that these results show a considerable improvement in outcome, further multicenter controlled studies are required to determine the optimum drugs and regimens to be used.

Limited Role of Antithrombin Deficiency in Hypercoagulopathy Associated with Nephrotic Syndrome

Background: Nephrotic syndrome (NS) is associated with an acquired hypercoagulopathy that drives venous thromboembolic comorbidities. The molecular mechanisms underlying NS-associated hypercoagulopathy are incompletely understood, however previous studies proposed marked urinary loss of antithrombin (AT) as a primary etiology. We have previously demonstrated, in rodent NS models, that there is no correlation between AT antigen and thrombin generation, which we have previously used to characterize the hypercoagulopathy. The objective of this study is to examine the association between AT antigen, AT activity, and hypercoagulopathy along with NS disease severity markers (proteinuria and plasma albumin) in 2 cohorts that include both pediatric and adult NS patients.Methods: Plasma samples were obtained from both cohorts as follows: (1) Samples were obtained on presentation from 147 adult and pediatric patients participating in the NEPTUNE prospective observational cohort study (2) Samples were obtained on presentation and after 7 weeks of glucocorticoid therapy (GC) in steroid sensitive and steroid resistant pediatric patients participating in the PNRC study. AT antigen and activity assays were performed using ELISA and chromogenic assays, respectively. Thrombin generation assay, plasma albumin, and urine protein-to-creatinine ratio were determined as previously described.Results: There was no significant relationship between AT antigen or AT activity and thrombin generation parameters. AT antigen and activity also did not correlate with NS severity markers (plasma albumin and proteinuria) in the NEPTUNE cohort (Figure1). In PNRC pediatric cohort, no significant correlation was found between AT antigen and thrombin generation or other disease severity markers. However, AT activity was significantly associated with both plasma albumin and endogenous thrombin potential at presentation (Figure 2) and at follow-up. Interestingly, GC therapy significantly improved AT activity in steroid-sensitive but not steroid-resistant NS patients (Figure 3). A comprehensive literature review and meta-analysis was also performed which revealed that clinically significant AT deficiency (<0.7 IU/mL) is uncommon in both pediatric and adult NS patients.Conclusion: AT antigen does not correlate with thrombin generation-defined hypercoagulopathy in adult or pediatric NS patients. AT activity does correlate with hypercoagulopathy in pediatric NS patients and improves significantly with successful remission inducing therapy. These data suggest that pediatric NS patients may have a qualitative, but not quantitative, AT deficiency that is responsive to therapy. The mechanism underlying this qualitative deficiency should be characterized in future studies. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Liposorber® LA-15 system for LDL apheresis in resistant nephrotic syndrome patients.

Steroid-resistant nephrotic syndrome (SRNS) is a major cause of stage 5 chronic kidney disease (CKD 5) in children. LDL apheresis (LDL-A) is now FDA approved for the treatment of pediatric focal segmental glomerulosclerosis (FSGS). Effective management of hyperlipidemia with LDL-A in SRNS patients may prevent progression of kidney disease and lead to remission. We report a case series of patients who received LDL-A for treatment of SRNS METHODS: We describe five children with SRNS who were treated with 12 sessions of LDL-A. Partial remission (PR) is defined as urine protein to creatinine ratio (UPC) of 0.2-2 (g/g) or decrease in UPC ≥ 50%, and complete remission (CR) is defined asUPC < 0.2 (g/g). One patient achieved CR and three achieved PR. One patient did not respond to therapy. The earliest that a patient achieved PR was at treatment #10 and some did not respond until after LDL-A was completed. Those who responded stayed in either CR or PR for extended periods of time. LDL-A was successful at significantly reducing LDL (p < 0.001), total cholesterol (p < 0.001), and triglyceride (p < 0.001). LDL-A was able to significantly decrease the lipid levels in these patients and induce CR and PR in the majority. The current study confirms previous studies showing those with a higher glomerular sclerosis burden were less likely to respond. LDL-A should be considered in patients with treatment-resistant SRNS and should be considered before there is a high burden of glomerular sclerosis to provide the best chance of success.

The immune cell landscape of peripheral blood mononuclear cells from PNS patients

Existing research suggests that the human immune system and immune cells are involved in the pathogenesis of nephrotic syndrome, but there is still a lack of direct evidence. This study tried to analyze the profiling of immune cells in the peripheral blood of steroid-sensitive nephrotic syndrome (SSNS) patients and steroid-resistant nephrotic syndrome (SRNS) patients before and after standard steroid treatment to clarify the immunological mechanism of nephrotic syndrome patients. The number and proportion of CD4 + T cells in patients with nephrotic syndrome remained unchanged. However, there is an imbalance of Th1 and Th2 and an excessive increase of Th17 cells. The number of CD8 + T cells and the number of effector CD8 + T cells in them increased significantly, but only in SSNS, the number of activated CD8 + T cells increased, and the number of activated Treg cells decreased significantly. Nephrotic syndrome patients also have B cell disorder, and it is more prominent in SSNS patients. Compared with the normal control, only the number of B cells and plasmablast in SSNS patients increased significantly (Z = − 2.20, P = 0.028). This study also observed that transitional B cells decreased in both SSNS and SRNS patients, but SSNS patients' decrease was lower than in SRNS patients. Compared with normal controls, monocytes in patients with nephrotic syndrome decreased significantly. The main reason was that Non-classical Monocyte decreased, while Classical Monocyte increased slightly. The total number of NK cells did not change, but the internal cell subgroups' composition occurred. Changes, realized as CD56hi NK cells increased, CD56low NK cells decreased; and the above trend is more evident in SSNS patients. Patients with nephrotic syndrome have immune disorders, including T cells, B cells, Monocytes, and NK cells. It can be confirmed that immune factors are involved in the pathogenesis of the nephrotic syndrome.