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Background: Recurrence of focal segmental glomerulosclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) after kidney transplant leads to significant morbidity and potentially earlier allograft loss. To date however, reported rates, risk factors and treatment outcomes have varied widely., Methods: We applied computational phenotypes to a multicenter aggregation of electronic health records data from 7 large pediatric health systems in the USA, to identify recurrence rates, risk factors, and treatment outcomes. We refined the data collection by chart review., Results: From > 7 million patients, we compared children with primary FSGS/SRNS who received a kidney transplant between 2009 and 2020 and who either developed recurrence (n = 67/165; 40.6%) or did not (n = 98/165). Serum albumin level at time of transplant was significantly lower and recipient HLA DR7 presence was significantly higher in the recurrence group. By 36 months post-transplant, complete remission occurred in 58.2% and partial remission in 17.9%. Through 6 years post-transplant, no remission after recurrence was associated with an increased risk of allograft loss over time (p < 0.0001), but any remission showed similar allograft survival and function decline to those with no recurrence. Since treatments were used in non-random fashion, using spline curves and multivariable non-linear analyses, complete + partial remission chance was significantly higher with greater plasmapheresis sessions, CTLA4-Ig doses or LDL-apheresis sessions. Only treatment with anti-CD20, CTLA4-Ig agents, or LDL-apheresis sessions were associated with complete remission. Excluding 25 patients with mutations did not significantly change our results., Conclusions: Our contemporary high-risk cohort had higher favorable response rates than most prior reports, from combinations of agents., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

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., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure StatementThe authors declare that the article was not published or under consideration, in part or whole, simultaneously in any other journal or proceedings. The authors state that each of the authors listed in the article has seen and approved the submission of this version of the article and takes full responsibility for the article.

Background: Minimal Change Disease (MCD) and Focal Segmental Glomerulosclerosis (FSGS) are a spectrum of disease causing the nephrotic syndrome (NS), characterised by proteinuria with debilitating oedema, as well as a high risk of venous thromboembolic disease and infection. Untreated, 50-60% patients with FSGS progress to end stage kidney disease after 5 years. These diseases respond to immunosuppression with high dose glucocorticoids, but 75% will relapse as the glucocorticoids are withdrawn, leading to significant morbidity associated with prolonged use. In children, the B cell depleting monoclonal antibody rituximab reduces relapse risk, but this drug has not been tested in randomised controlled trial in adults., Methods: 130-150 adults with new or relapsing MCD/FSGS, from UK Renal Units, are being randomised to receive either rituximab (two 1 g infusions two weeks apart) or placebo. Partipicipants are recruited when they present with nephrosis, and all are treated with glucocorticoids as per KDIGO guidelines. Once in remission, prednisolone is withdrawn according to a pre-specified regimen. If in remission at 6 months, participants receive a further dose of trial drug. If they relapse, they are unblinded, and if they have received placebo, they are offered open label rituximab with protocolised prednisolone as in the main phase of the trial. The primary end point is time from remission to relapse. A number of secondary endpoints will be assessed including the effect of rituximab on: (1) NHS and societal resource use and hence cost: (2) safety: (3) other measures of efficacy, such as achievement of partial and complete remission of NS and the preservation of renal function: (4) health status of participant., Trial Registration: TURING received ethical approval on 14 Jun 2019 - REC reference: 19/LO/0738. It is registered on EudraCT, with ID number: 2018-004611-50, with a start date of 2019-06-14., (© 2024. The Author(s).)

Idiopathic nephrotic syndrome (NS) is a heterogeneous group of glomerular disorders which includes two major phenotypes: minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). MCD and FSGS are classic types of primary podocytopathies. We aimed to explore the molecular mechanisms in NS triggered by primary podocytopathies and evaluate diagnostic value of the selected proteomic signatures by analyzing blood proteome profiling. Totally, we recruited 90 participants in two cohorts. The first cohort was analyzed using label-free quantitative (LFQ) proteomics to discover differential expressed proteins and identify enriched biological process in NS which were further studied in relation to clinical markers of kidney injury. The second cohort was analyzed using parallel reaction monitoring-based quantitative proteomics to verify the data of LFQ proteomics and assess the diagnostic performance of the selected proteins using receiver-operating characteristic curve analysis. Several biological processes (such as immune response, cell adhesion, and response to hypoxia) were found to be associated with kidney injury during MCD and FSGS. Moreover, three proteins (CSF1, APOC3, and LDLR) had over 90% sensitivity and specificity in detecting adult NS triggered by primary podocytopathies. The identified biological processes may play a crucial role in MCD and FSGS pathogenesis. The three blood protein markers are promising for diagnosing adult NS triggered by primary podocytopathies.

Focal segmental glomerulosclerosis (FSGS) is a complex disease which describes different kinds of kidney defects, not exclusively linked with podocyte defects. Since nephrin mutation was first described in association with early-onset nephrotic syndrome (NS), many advancements have been made in understanding genetic patterns associated with FSGS. New genetic causes of FSGS have been discovered, displaying unexpected genotypes, and recognizing possible site of damage. Many recent large-scale sequencing analyses on patients affected by idiopathic chronic kidney disease (CKD), kidney failure (KF) of unknown origin, or classified as FSGS, have revealed collagen alpha IV genes, as one of the most frequent sites of pathogenic mutations. Also, recent interest in complex and systemic lysosomal storage diseases, such as Fabry disease, has highlighted GLA mutations as possible causes of FSGS. Tubulointerstitial disease, recently classified by KDIGO based on genetic subtypes, when associated with UMOD variants, may phenotypically gain FSGS features, as well as ciliopathy genes or others, otherwise leading to completely different phenotypes, but found carrying pathogenic variants with associated FSGS phenotype. Thus, glomerulosclerosis may conceal different heterogeneous conditions. When a kidney biopsy is performed, the principal objective is to provide an accurate diagnosis. The broad spectrum of phenotypic expression and genetic complexity is demonstrating that a combined path of management needs to be applied. Genetic investigation should not be reserved only to selected cases, but rather part of medical management, integrating with clinical and renal pathology records. FSGS heterogeneity should be interpreted as an interesting opportunity to discover new pathways of CKD, requiring prompt genotype-phenotype correlation. In this review, we aim to highlight how FSGS represents a peculiar kidney condition, demanding multidisciplinary management, and in which genetic analysis may solve some otherwise unrevealed idiopathic cases. Unfortunately there is not a uniform correlation between specific mutations and FSGS morphological classes, as the same variants may be identified in familial cases or sporadic FSGS/NS or manifest a variable spectrum of the same disease. These non-specific features make diagnosis challenging. The complexity of FSGS genotypes requires new directions. Old morphological classification does not provide much information about the responsible cause of disease and misdiagnoses may expose patients to immunosuppressive therapy side effects, mistaken genetic counseling, and misguided kidney transplant programs., (© 2023. The Author(s).)

We herein report three cases of steroid-resistant nephrotic syndrome successfully treated with low-density lipoprotein apheresis (LDL-A). All patients were treated with a combination of steroids, cyclosporine, and LDL-A. In all cases, the serum concentrations of LDL, total and high-density lipoprotein cholesterol, and triglycerides were significantly lowered following LDL-A administration. Furthermore, the estimated LDL receptor activity increased, while both serum LDL and total cholesterol levels decreased, suggesting that LDL-A increases LDL receptor activity by driving changes in serum cholesterol concentration. This case series suggests that LDL-A increases LDL receptor activity, which may improve the intracellular uptake of cyclosporine.

Background: Systemic scleroderma (SSc) is an insidious autoimmune connective tissue disorder with multiorgan involvement. Renal involvement is one of the important causes of morbidity and mortality in scleroderma; however, nephrotic syndrome is reported rarely in association with SSc. We present a patient with SSc who developed focal segmental glomerulosclerosis (FSGS) as a complication of scleroderma., Case Presentation: A 59 year old Caucasian female patient, with a known history of diffuse systemic sclerosis from 8 years, presented to our clinic with symptoms of anasarca and weight gain. Her physical examination was unremarkable except for periorbital and extremity edema. Her biochemistry assessment revealed decreased serum albumin levels and elevated serum creatinine levels. A renal biopsy was performed, which showed histopathological patterns of FSGS type of nephrotic syndrome. After administration of high doses of steroid and rituximab in the course of her treatment for 6 months, her symptoms and proteinuria were improved without the occurrence of scleroderma renal crises., Conclusion: SSc is a complex multisystemic autoimmune disorder. SRC is the most prominent renal involvement in SSc, but other renal pathologies may also occur. Each patient should be precisely investigated since managing these renal conditions can differ significantly. Nephrotic syndrome is a rare complication of SSc, which could be managed with prompt diagnosis and steroid administration., (© 2024. The Author(s).)

Introduction: Rituximab has been proven effective and safe in pediatric patients with frequently relapsing or steroid-dependent nephrotic syndrome (FR/SDNS). We aimed to analyze the efficacy and safety of rituximab in adult FR/SDNS patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS)., Methods: A retrospective cohort study at three nephrology centers in China included adult FR/SDNS patients with biopsy-proven MCD or FSGS. Primary outcomes were relapse frequency and first relapse-free survival time. Adverse events were well recorded, and logistic regression analyses were used to investigate the risk factors of relapse., Results: Eighty-one patients (age, 25.0 years; interquartile range, 20.0-40.5; 67% males; 82.7% MCD) received an average rituximab dose of 1,393.8 ± 618.7 mg/2 years during the 2-year follow-up period. The relapse frequency, calculated as the ratio of relapse times to follow-up years, significantly decreased after rituximab treatment (0.04 [0.00, 0.08] vs. 1.71 [1.00, 2.45], p &lt; 0.001). The first relapse-free survival time was 16.7 ± 8.0 months. Fifty-seven patients (70.4%) achieved cessation of corticosteroids and immunosuppressants within 3 months after the first rituximab infusion. Adverse events were mostly mild, and no severe treatment-related adverse events were observed. Low serum albumin level before rituximab and high CD56+CD16+ natural killer cell count after rituximab were independent risk factors of relapse within 2 years after rituximab treatment., Conclusion: Rituximab was proven an effective and safe treatment option for adult FR/SDNS patients with MCD or FSGS in maintaining disease remission and minimizing corticosteroid exposure., (© 2023 S. Karger AG, Basel.)

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is known to play a crucial role in dyslipidemia, and an increase in serum PCSK9 levels has also been reported in patients with nephrotic syndrome (NS). However, the specific effects of PCSK9 in kidney disease and the therapeutic potential of targeting PCSK9 in NS remain elusive. We thus investigated the effects of evolocumab (EVO) in mice with adriamycin (ADR)-induced NS. Male BALB/c mice were divided into the following 4 groups: Control, N = 11; EVO (monoclonal antibody for PCSK9), N = 11; ADR, N = 11; and ADR+EVO, N = 11. We also performed in vitro experiments using immortalized murine podocyte cells to validate the direct effects of PCSK9 on podocytes. EVO decreased urinary albumin levels and ameliorated podocytopathy in mice with ADR nephropathy. Further, EVO suppressed the Nod-like receptor protein 3 (NLRP3) inflammasome pathway in podocytes. PCSK9 expression upregulated CD36, a scavenger receptor of oxidized low-density lipoprotein (Ox-LDL), which in turn stimulated the absorption of Ox-LDL in vitro. EVO downregulated CD36 expression in podocytes both in vitro and in vivo. Immunofluorescence staining analysis reveals that CD36 and PCSK9 colocalized in the glomerular tufts of mice with ADR nephropathy. In the patients with focal segmental glomerulosclerosis, the CD36 + area in glomerular tufts increased compared with those diagnosed with minor glomerular abnormalities. This study revealed that EVO ameliorated mouse ADR nephropathy through the regulation of CD36 and NLRP3 inflammasome signaling. EVO treatment represents a potential therapeutic strategy for human NS., (Copyright © 2023 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Nephrotic syndrome affects about 2-7 per 100,000 children yearly and accounts for less than 15% of end stage kidney disease. Steroids still represent the cornerstone of therapy achieving remission in 75-90% of the cases The remaining part result as steroid resistant nephrotic syndrome, characterized by the elevated risk of developing end stage kidney disease and frequently presenting disease recurrence in case of kidney transplant. The pathogenesis of nephrotic syndrome is still far to be elucidated, however, efficacy of immune treatments provided the basis to suggest the involvement of the immune system in the pathogenesis of the disease. Based on these substrates, more immune drugs, further than steroids, were administered in steroid resistant nephrotic syndrome, such as antiproliferative and alkylating agents or calcineurin inhibitors. However, such treatments failed in inducing a sustained remission. In last two decades, the developments of monoclonal antibodies, including the anti-CD20 rituximab and inhibitor of B7-1 abatacept, represented a valid opportunity of treatment. However, also the effectiveness of biologics resulted limited. We here propose a new hypothesis-driven treatment based on the combining administration of rituximab with the anti-CD38 monoclonal antibody daratumumab (NCT05704400), sustained by the hypothesis to target the entire B-cells subtypes pool, including the long-lived plasmacells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Angeletti, Bruschi, Kajana, La Porta, Spinelli, Caridi, Lugani, Verrina and Ghiggeri.)

Background: Focal segmental glomerulosclerosis (FSGS) is a primary podocytopathy characterized by primary podocyte detection and high proteinuria. The search for biomarkers and factors associated with the progression of this disease is an important task nowdays., Aim: To assess the proteomic profile of urine in patients with FSGS and to isolate urinary biomarkers of podocytopathies., Materials and Methods: The study included 41 patients diagnosed with chronic glomerulonephritis, 27 men and 14 women. According to the morphological study, 28 patients were diagnosed with FSGS, 9 with steroid-sensitive nephrotic syndrome and 14 with steroid-resistant nephrotic syndrome. The comparison group included 13 patients with membranous nephropathy. The study of the urinary proteome was carried out by targeted liquid chromatography-mass spectrometry using multiple reaction monitoring with synthetic stable isotope labelled peptide standards., Results: The main differences in the protein profile of urine were found in the subgroups of steroid-sensitive (SS) and steroid-resistant (SR) FSGS. In the FSGS SR group, at the onset of the disease, there was a high concentration of proteins reflecting damage to the glomerular filter (apo-lipoprotein A-IV, orosomucoid, cadherin, hemopexin, vitronectin), as well as proteins associated with tubulo-interstitial inflammation and accumulation of extracellular matrix (retinol- and vitamin D-binding proteins, kininogen-1, lumican and neurophilin-2). Compared with the membranous nephropathy group, FSGS patients had significantly higher urinary concentrations of carnosinase, orosomucoid, cadherin-13, tenascin X, osteopontin, and zinc-alpha-2-glycoprotein., Conclusion: Thus, in patients with SR FSGS, the proteomic profile of urine includes more proteins at elevated concentrations, which reflects severe damage to various parts of the nephron compared with patients with SS FSGS and membranous nephropathy.

Background/aim: Nephrotic syndrome is the most common glomerular disease of childhood. Majority of the idiopathic cases frequently respond to steroid therapy and are regarded as steroid-sensitive nephrotic syndrome. Several studies have reported a change in this usual pattern to steroid-resistant nephrotic syndrome in Nigerian children. This study aimed to determine the pattern of steroid sensitivity and steroid resistance in childhood idiopathic nephrotic syndrome seen at a tertiary hospital in Enugu, south-east Nigeria., Materials and Methods: A retrospective study conducted in children with idiopathic nephrotic syndrome seen at the University of Nigeria Teaching Hospital, Ituku-Ozalla Enugu, over 5 years (from 2016 to 2020). The demographic variables, clinical data, and histopathological pattern were documented. Renal biopsies were studied by light microscope only., Results: Of a total of 150 patients, 105 (70%) were males, while 45 (30%) were females. Ninety six (64%) were aged 1-10 years. Fifty four (36%) were aged 11-18 years. Forty eight (32%) were aged 1-5 years. Mean age was 8.67 ± 4.69 years. One hundred and six (71%) initially had steroid-sensitive nephrotic syndrome; 12 (11.3%) and seven (6.6%) later became frequent-relapsers and steroid-dependent, respectively. Forty four (29.3%) had steroid-resistant nephrotic syndrome. Sixty eight had renal biopsy; the most common indication being steroid-resistance. The most common histological pattern was focal segmental glomerulosclerosis seen in 63.2% of these patients. Only four (9%) had renal transplant., Conclusion: Although the prevalence of steroid-sensitive nephrotic syndrome is higher in this clime, there is a rising incidence of steroid-resistant pattern attributed to incident cases of focal segmental glomerulosclerosis., Competing Interests: None

Introduction: Minimal change nephrotic syndrome (MCNS) and focal segmental glomerulosclerosis (FSGS) are the two common causes of nephrotic syndrome (NS) in both children and adults with overlapping clinical features, but with distinct prognostic and therapeutic implications. The distinction between these relies entirely on histopathology, which can sometimes be difficult. CD44 is expressed by activated parietal epithelial cells, plays a role in matrix deposition and thus in the pathogenesis of FSGS., Aims: To assess the expression of CD44 in MCNS and FSGS and to evaluate its association with the known clinical and histopathological prognostic factors., Materials and Methods: Thirty cases each of MCNS and FSGS were studied. The clinical, laboratory, histopathological, and CD 44 immunohistochemical data were recorded. The findings were analyzed and correlated. A P value of < 0.05 was considered statistically significant., Results: Statistical association was noted between CD44 positivity and serum creatinine (p = 0.031), estimated glomerular filtration rate (p = 0.040), segmental sclerosis (p < 0.001), tubular atrophy (p = 0.027), interstitial fibrosis (p = 0.027), and histological diagnosis (p < 0.001). The sensitivity, specificity, positive predictive, and negative predictive values were 90%, 76.67%, 79.41% and 88.46%, respectively., Conclusions: CD44 immunostain can effectively distinguish MCNS from FSGS. The congruent results of CD44 positivity with known prognostic factors support the possibility of using the CD44 marker as a predictive tool in selecting high-risk patients and offering appropriate therapeutic measures., Competing Interests: None

Background: Idiop athic nephrotic syndrome (INS) is classified in children according to response to initial corticosteroid therapy into steroid-sensitive (SSNS) and steroid-resistant nephrotic syndrome (SRNS), and in adults according to histology into minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). However, there is well-recognised phenotypic overlap between these entities. Genome-wide association studies (GWAS) have shown a strong association between SSNS and variation at HLA, suggesting an underlying immunological basis. We sought to determine whether a risk score generated from genetic variants associated with SSNS could be used to gain insight into the pathophysiology of INS presenting in other ways., Methods: We developed an SSNS genetic risk score (SSNS-GRS) from the five variants independently associated with childhood SSNS in a previous European GWAS. We quantified SSNS-GRS in independent cohorts of European individuals with childhood SSNS, non-monogenic SRNS, MCD, and FSGS, and contrasted them with SSNS-GRS quantified in individuals with monogenic SRNS, membranous nephropathy (a different immune-mediated disease-causing nephrotic syndrome), and healthy controls., Results: The SSNS-GRS was significantly elevated in cohorts with SSNS, non-monogenic SRNS, MCD, and FSGS compared to healthy participants and those with membranous nephropathy. The SSNS-GRS in all cohorts with non-monogenic INS were also significantly elevated compared to those with monogenic SRNS., Conclusions: The shared genetic risk factors among patients with different presentations of INS strongly suggests a shared autoimmune pathogenesis when monogenic causes are excluded. Use of the SSNS-GRS, in addition to testing for monogenic causes, may help to classify patients presenting with INS. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2022. The Author(s).)

Background: Kidney biopsy remains the best standard for kidney tissue analysis. Although percutaneous kidney biopsy is an invasive procedure, it is an indispensable part of interventional nephrology for accurate diagnosis, selection of appropriate therapy protocol, and prognostication of kidney diseases in children. With improvement in expertise among pediatric nephrologists, data on procedure outcomes are now being documented. Aim: We aimed to describe the outcomes in a 5-year practice of kidney biopsy at the pediatric nephrology unit in a southeast Nigerian tertiary hospital., Patients and Methods: An observational descriptive study conducted on the kidney biopsy performed in our facility from 2017 to 2022. The focus was on the patients' clinical profile, indications for biopsy, the adopted procedure, and the histopathologic findings., Results: A total of 69 patients had kidney biopsy, 40 (58.0%) were males, while 29 (42.0%) were females. Sixty-four (92.7%) patients had the procedure at the age of >10 years, while five (7.2%) at the age of <7 years. The patients' prebiopsy mean systolic and diastolic blood pressures were 111.20 ± 16.93 and 74.64 ± 12.69 mmHg, respectively. Their estimated glomerular filtration rate (eGFR) was 119.27 ± 52.78 ml/min/1.73 m 2 . The most frequent indication was steroid resistance (39/69, 56.5%). Focal segmental glomerulosclerosis was the commonest histopathologic finding (38/69, 55.0%)., Conclusion: Outcomes of percutaneous kidney biopsy at a Nigerian tertiary hospital are adjudged successful. The histopathologic patterns highlight FSGS as the major cause of steroid resistance in childhood nephrotic syndrome in this clime., Competing Interests: None

Background: Sequential rituximab (RTX) administration has emerged as an important strategy to sustain remission of disease in patients with difficult-to-treat nephrotic syndrome., Methods: We report the efficacy and safety of sequential therapy with two or more courses of intravenous RTX in 250 patients with difficult-to-treat steroid dependence (n = 127) and calcineurin inhibitor (CNI)-dependent or CNI-refractory steroid resistance (n = 123) managed at one center during 2015-2021. Subsets of patients were cross-sectionally tested for hypogammaglobulinemia, seroprotection against and hyporesponsiveness to vaccines for hepatitis B and tetanus, BK/JC viruria and human antichimeric antibodies (HACAs)., Results: Sequential RTX therapy, initiated at a median of 10 years [interquartile range (IQR) 7.3-14.4], was administered for 1.8 courses/person-year [95% confidence interval (CI) 1.7-2.0] over 2.0 years (95% CI 1.2-3.0). Therapy was associated with postponement of relapses by a median of 3 years in patients with steroid-sensitive disease and 2 years in those with steroid resistance. Relapses were reduced by a mean of 2.0 relapses/person-year (95% CI 1.8-2.2), enabling a reduction in prednisolone dose to 0.04 mg/kg/day (95% CI 0.01-0.11) and withdrawal of additional immunosuppression in 154 (62%) patients. RTX-associated adverse events, occurring at 0.20 events/person-year (95% CI 0.17-0.23), were chiefly comprised of infusion reactions (n = 108) and infections (n = 46); serious adverse events were observed in 10.8% patients, at 0.03 events/person-year (95% CI 0.02-0.05). Hypogammaglobulinemia was observed in 35% of 177 patients and was moderate to severe in 8.5% of cases. Rates of seroprotection at baseline and response following vaccination were lower for hepatitis B [1.9% and 29.4% (n = 52)] than tetanus [65.5% and 34.5% (n = 58)]. BK/JC viruria, without viremia, was observed in 7.3% of 109 cases. A total of 19 of 107 patients (17.8%) had HACAs, which were associated with B cell nondepletion and serum sickness. Age at therapy of <9-10 years was associated with a risk of early relapse, treatment failure and hypogammaglobulinemia following RTX therapy., Conclusions: Sequential therapy with RTX effectively reduces relapses in patients with difficult-to-treat steroid- and/or CNI-dependent or CNI-refractory nephrotic syndrome. Therapy is associated with high rates of hypogammaglobulinemia and infusion reactions., (© The Author(s) 2022. Published by Oxford University Press on behalf of the ERA.)

Background: Galloway-Mowat syndrome (GAMOS) is a group of rare hereditary diseases by the combination of early onset steroid-resistant nephrotic syndrome (SRNS) and microcephaly with brain anomalies caused by WDR73, LAGE3, OSGEP, TP53RK, TPRKB, GON7, WDR4 or NUP133 mutations., Case Presentation: We present the clinical and genetic features of a two-year-old boy with early nephrotic syndrome, microcephaly, growth retardation hypotonia and hypothyroidism. Genetic testing showed the presence of a canonical-splice mutation in the LAGE3 gene (NM&#95;006014: c.188 + 1C > T). A total of nine female members of the family carried the variant. Seven male members died prematurely, and three of them suffered from nephrotic syndrome, which is consistent with the x-linked gene map of the disease. The overall symptoms of the disease due to the LAGE3 mutation were mild compared to other pathogenic genes., Conclusion: As far as we know, this is the largest family case of GAMOS2 caused by LAGE3 mutation found so far. We also compared other subtypes of GAMOS. Due to the heterogeneity of the renal phenotype, regular proteinuria screening is recommended for all patients diagnosed with GAMOS., (© 2023. The Author(s).)

Background: Establishing a molecular genetic diagnosis of focal segmental glomerulosclerosis (FSGS)/steroid-resistant nephrotic syndrome (SRNS) can be useful for predicting post-transplant recurrence. Monogenic causes are reportedly present in approximately 20-30% of patients with FSGS/SRNS. However, the characteristics of patients who are likely to have a monogenic cause remain to be determined., Methods: Pediatric recipients with SRNS and/or biopsy-proven FSGS who underwent their first kidney transplantation at our center between 1999 and 2019 were analyzed. Patients with secondary FSGS/SRNS were excluded. The recipients were divided into three groups: familial/syndromic, presumed primary, and undetermined FSGS/SRNS. Patients who met all of the following criteria were categorized as having presumed primary FSGS/SRNS: (i) nephrotic syndrome, (ii) complete or partial remission with initial steroid therapy and/or additional immunosuppressive therapies, and (iii) diffuse foot process effacement on electron microscopy in the native kidney biopsy. All patients underwent genetic testing using next-generation sequencing., Results: Twenty-four patients from 23 families were analyzed in this study. Pathogenic or likely pathogenic variants in FSGS/SRNS-related genes were identified in four of four families, zero of eight families, and 10 of 11 families with familial/syndromic, presumed primary, and undetermined FSGS/SRNS, respectively. Post-transplant recurrence only occurred in patients with presumed primary FSGS/SRNS., Conclusions: Our systematic approach based on precise clinicopathological findings including nephrotic syndrome, treatment responses, and diffuse foot process effacement might be useful to differentiate pediatric kidney transplant recipients with FSGS/SRNS who are likely to have a monogenic cause from patients who are not, and to predict post-transplant recurrence. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2022. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Background: In children, focal segmental glomerulosclerosis (FSGS) is the main cause of steroid resistant nephrotic syndrome (SRNS). To identify specific candidates and the mechanism of steroid resistance, we examined the formalin-fixed paraffin embedded (FFPE) renal tissue protein profiles via liquid chromatography tandem mass spectrometry (LC-MS/MS)., Methods: Renal biopsies from seven steroid-sensitive (SS) and eleven steroid-resistant (SR) children FSGS patients were obtained. We examined the formalin-fixed paraffin embedded (FFPE) renal tissue protein profiles via liquid chromatography tandem mass spectrometry (LC-MS/MS). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and Gene Ontology (GO) analysis, as well as the construction of protein-protein interaction (PPI) network were performed. Two proteins were further valiadated by immunohistochemistry staining in FSGS patients and mice models., Results: In total, we quantified more than 4000 proteins, of which 325 were found to be differentially expressed proteins (DEPs) between the SS and SR group (foldchange ≥2, P<0.05). The results of GO revealed that the most significant up-regulated proteins were primarily related to protein transportation, regulation of the complement activation process and cytolysis. Moreover, clustering analysis showed differences in the pathways (lysosome, terminal pathway of complement) between the two groups. Among these potential candidates, validation analyses for LAMP1 and ACSL4 were conducted. LAMP1 was observed to have a higher expression in glomerulus, while ACSL4 was expressed more in tubular epithelial cells., Conclusions: In this study, the potential mechanism and candidates related to steroid resistance in children FSGS patients were identified. It could be helpful in identifying potential therapeutic targets and predicting outcomes with these proteomic changes for children FSGS patients., (© 2022. The Author(s).)

Idiopathic nephrotic syndrome often responds to immunosuppressive treatment. Nevertheless, this syndrome-and the drugs used to treat it-remain important causes of patient morbidity. Idiopathic nephrotic syndrome is usually caused by minimal change disease or FSGS, diseases that primarily affect the podocytes. In spite of decades of research, the underlying causes of both diseases remain incompletely understood. There is, however, a large body of observational and experimental data linking the immune system with both minimal change disease and FSGS, including associations with systemic infections and hematologic malignancies. Perhaps most compellingly, many different immunomodulatory drugs are effective for treating idiopathic nephrotic syndrome, including biologic agents that have well-defined immune targets. In fact, the unexpected efficacy of targeted therapeutic agents has provided important new insights into the pathogenesis of these diseases. Given the large number of drugs that are available to deplete or block specific cells and molecules within the immune system, a better understanding of the immunologic causes of idiopathic nephrotic syndrome may lead to better diagnostic and therapeutic approaches., (Copyright © 2022 by the American Society of Nephrology.)

Background: Variants in TBC1D8B cause nephrotic syndrome. TBC1D8B is a GTPase-activating protein for Rab11 (RAB11-GAP) that interacts with nephrin, but how it controls nephrin trafficking or other podocyte functions remains unclear., Methods: We generated a stable deletion in Tbc1d8b and used microhomology-mediated end-joining for genome editing. Ex vivo functional assays utilized slit diaphragms in podocyte-like Drosophila nephrocytes. Manipulation of endocytic regulators and transgenesis of murine Tbc1d8b provided a comprehensive functional analysis of Tbc1d8b., Results: A null allele of Drosophila TBC1D8B exhibited a nephrocyte-restricted phenotype of nephrin mislocalization, similar to patients with isolated nephrotic syndrome who have variants in the gene. The protein was required for rapid nephrin turnover in nephrocytes and for endocytosis of nephrin induced by excessive Rab5 activity. The protein expressed from the Tbc1d8b locus bearing the edited tag predominantly localized to mature early and late endosomes. Tbc1d8b was required for endocytic cargo processing and degradation. Silencing Hrs , a regulator of endosomal maturation, phenocopied loss of Tbc1d8b . Low-level expression of murine TBC1D8B rescued loss of the Drosophila gene, indicating evolutionary conservation. Excessive murine TBC1D8B selectively disturbed nephrin dynamics. Finally, we discovered four novel TBC1D8B variants within a cohort of 363 patients with FSGS and validated a functional effect of two variants in Drosophila, suggesting a personalized platform for TBC1D8B -associated FSGS., Conclusions: Variants in TBC1D8B are not infrequent among patients with FSGS. TBC1D8B, functioning in endosomal maturation and degradation, is essential for nephrin trafficking., (Copyright © 2022 by the American Society of Nephrology.)

Background: The associations of focal segmental glomerulosclerosis (FSGS) histological variants with renal outcomes have rarely been investigated comprehensively by clinically relevant subgroups in this modern age., Methods: Data on 304 (173 nephrotic and 131 non-nephrotic) patients with biopsy-confirmed FSGS from 2010 to 2013 were analyzed using the Japanese nationwide renal biopsy registry. The primary outcome was a composite of a 30% decline in estimated glomerular filtration rate or progression to end-stage kidney disease 5 years from the biopsy. We compared outcomes of FSGS variants according to the Columbia classification using survival analyses. Subgroup analyses were performed based on nephrotic syndrome (NS), immunosuppression and proteinuria remission (PR; proteinuria <0.3 g/day) during follow-up. Additionally, associations of NS, immunosuppression and PR with outcomes were examined for each variant., Results: The distribution of variants was 48% (n = 145) FSGS not otherwise specified, 19% (n = 57) tip, 15% (n = 47) perihilar, 13% (n = 40) cellular and 5% (n = 15) collapsing. The outcome event occurred in 87 patients (29%). No significant differences in the outcome were found among the variants. Subgroup analyses yielded similar results. However, there was a trend toward improved outcome in patients with PR irrespective of variants [hazard ratio adjusted for histological variant and potential confounders (adjusted HR) 0.19 (95% confidence interval 0.10-0.34)]. NS was marginally associated with better outcome compared with non-NS [adjusted HR 0.50 (95% confidence interval 0.25-1.01)]., Conclusions: FSGS variants alone might not have significant impacts on the renal outcome after 5 years, while PR could be predictive of improved renal prognosis for any variant. Specific strategies and interventions to achieve PR for each variant should be implemented for better renal outcomes., (© The Author(s) 2021. Published by Oxford University Press on behalf of ERA. All rights reserved.)

Background: The phenotypic and genotypic spectrum and kidney outcome of PLCε1-related kidney disease are not well known. We attempted to study 25 genetically confirmed cases of PLCε1-related kidney disease from 11 centers to expand the clinical spectrum and to determine the relationship between phenotypic and genotypic features, kidney outcome, and the impact of treatment on outcome., Methods: Data regarding demographics, clinical and laboratory characteristics, histopathological and genetic test results, and treatments were evaluated retrospectively., Results: Of 25 patients, 36% presented with isolated proteinuria, 28% with nephrotic syndrome, and 36% with chronic kidney disease stage 5. Twenty patients underwent kidney biopsy, 13 (65%) showed focal segmental glomerulosclerosis (FSGS), and 7 (35%) showed diffuse mesangial sclerosis (DMS). Of the mutations identified, 80% had non-missense, and 20% had missense; ten were novel. No clear genotype-phenotype correlation was observed; however, significant intrafamilial variations were observed in three families. Patients with isolated proteinuria had significantly better kidney survival than patients with nephrotic syndrome at onset (p = 0.0004). Patients with FSGS had significantly better kidney survival than patients with DMS (p = 0.007). Patients who presented with nephrotic syndrome did not respond to any immunosuppressive therapy; however, 4/9 children who presented with isolated proteinuria showed a decrease in proteinuria with steroids and/or calcineurin inhibitors., Conclusion: PLCε1-related kidney disease may occur in a wide clinical spectrum, and genetic variations are not associated with clinical presentation or disease course. However, clinical presentation and histopathology appear to be important determinants for prognosis. Immunosuppressive medications in addition to angiotensin-converting enzyme inhibitors may be beneficial for selected patients. "A higher resolution version of the Graphical abstract is available as Supplementary information"., (© 2021. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Background: Approximately 30% of children with steroid-resistant nephrotic syndrome (SRNS) have causative monogenic variants. SRNS represents glomerular disease resulting from various etiologies, which lead to similar patterns of glomerular damage. Patients with SRNS mainly exhibit focal segmental glomerulosclerosis (FSGS). There is limited information regarding associations between histologic variants of FSGS (diagnosed using on the Columbia classification) and monogenic variant detection rates or clinical characteristics. Here, we report FSGS characteristics in a large population of affected patients., Methods: This retrospective study included 119 patients with FSGS, diagnosed using the Columbia classification; all had been referred to our hospital for genetic testing from 2016 to 2021. We conducted comprehensive gene screening of all patients using a targeted next-generation sequencing panel that included 62 podocyte-related genes. Data regarding patients' clinical characteristics and pathologic findings were obtained from referring clinicians. We analyzed the associations of histologic variants with clinical characteristics, kidney survival, and gene variant detection rates., Results: The distribution of histologic variants according to the Columbia classification was 45% ( n =53) FSGS not otherwise specified, 21% ( n =25) cellular, 15% ( n =18) perihilar, 13% ( n =16) collapsing, and 6% ( n =7) tip. The median age at end stage kidney disease onset was 37 years; there were no differences in onset age among variants. We detected monogenic disease-causing variants involving 12 of the screened podocyte-related genes in 34% (40 of 119) of patients. The most common genes were WT1 (23%), INF2 (20%), TRPC6 (20%), and ACTN4 (10%). The perihilar and tip variants had the strongest and weakest associations with detection of monogenic variants (83% and 0%, respectively; P <0.001)., Conclusions: We revealed the distributions of histologic variants of genetic FSGS and nongenetic FSGS in a large patient population. Detailed data concerning gene variants and pathologic findings are important for understanding the etiology of FSGS., Competing Interests: R. Hamada reports research funding from Chugai Pharmaceutical Co., Ltd., Kyowa Kirin Co., Ltd., Takeda Pharmaceutical Co., and Teijin Pharma Ltd.; and honoraria from Alexion Pharmaceuticals, Inc., Asahi Kasei Pharma Corporation, Chugai Pharmaceutical Co., Ltd., and Teijin Pharma Ltd. T. Horinouchi reports research funding from Otsuka Pharmaceutical Co., Ltd. K. Iijima reports consultancy for JCR Pharmaceuticals Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Takeda Pharmaceutical Co., Ltd., and Zenyaku Kogyo Co., Ltd.; research funding from Air Water Medical, Inc., Astellas Pharma, Inc., Eisai Co., Ltd., JCR Pharmaceutical Co., Ltd., Mochida Pharmaceutical Co., Ltd., Nihon Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Shionogi & Co., Ltd., and Zenyaku Kogyo Co., Ltd.; honoraria from Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., Integrated Development Associates Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Shionogi & Co., Ltd., and Zenyaku Kogyo Co., Ltd.; a patent application on the development of antisense nucleotides for exon skipping therapy in Alport syndrome; and an advisory or leadership role for CJASN and Pediatric Nephrology (Editorial Board). S. Ito reports consultancy for Alexion Pharma, Takeda Pharmaceutical Company, Teijin Pharma, and Zenyaku Kogyo Co Ltd.; research funding from Asahi Kasei Pharma, Chugai Pharmaceutical Co., Ltd., CSL Behring, Kyowa Hakko Kirin Co., Ltd., Maruho Pharma, Mitsubishi Tanabe Pharma, and Teijin Pharma Ltd.; honoraria from Alexion Pharma, Teijin Pharma Ltd., and Zenyaku Kogyo Co., Ltd.; an advisory or leadership role for Clinical Experimental Nephrology, JMA Journal, and the Korean Journal of Pediatrics; and participation in a speakers’ bureau for AbbVie LLC, Alexion Pharma, Asahi Kasei Pharma, Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., CSL Behring, Daiichi Sankyo Co., Ltd., Mitsubishi Tanabe Pharma, Novartis Pharma K.K., Pfizer Japan, Inc., Sanofi Co., Ltd., Teijin Pharma Ltd., and Zenyaku Kogyo Co., Ltd. K. Kamei reports research funding from Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., Public Foundation of Vaccination Research Center, Taiju Life Social Welfare Foundation, Terumo Foundation for Life Sciences and Arts, Ono Pharmaceutical Co; Otsuka Pharmaceutical Co., Ltd., Teijin Pharma Ltd; Shionogi Co., Ltd.; and honoraria from Baxter Ltd., Tanabe Mitsubishi Pharma, and Zenyaku Kogyo Co., Ltd. K. Matsuoka reports participating in a speakers’ bureau for Chugai Pharmaceutical Co., Ltd. K. Nozu reports research funding from Chugai Pharmaceutical Company, Dainippon Sumitomo Pharmaceutical Company, Kyowa Kirin Pharmaceutical Company, and Shionogi, Inc.; patents or royalties from Daiichi Sankyo Pharmaceutical Company; an advisory or leadership role for Kyowa Kirin Pharmaceutical Company and Toa Eiyo Ltd.; and receiving lecture fees from Chugai Pharmaceutical Company, Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo Company, Ltd., Kyowa Kirin Pharmaceutical Company, Novartis Pharma Co., Ltd., and Sumitomo Dainippon Pharma Co., Ltd. All remaining authors have nothing to disclose., (Copyright © 2022 by the American Society of Nephrology.)

Background: Cases with asymptomatic proteinuria (ASP) not manifesting nephrotic syndrome often pathologically show focal segmental glomerulosclerosis (FSGS). However, characteristics of those cases had not been intensively studied so far., Methods: We retrospectively reviewed clinical, pathological, and genetic characteristics of 37 children (median age, 9.3 years) who underwent renal biopsy for persistent isolated proteinuria (urine protein-to-creatinine ratio: UP/C, > 0.2 g/g) between 2003 and 2019. Targeted next-generation sequencing (NGS) was utilized for all patients with FSGS, excluding those with secondary FSGS., Results: At biopsy, all patients with FSGS (N = 14) had UP/C ≥ 0.5 g/g and the median UP/C was significantly higher in those with FSGS than those with minor glomerular abnormalities (MGA) (N = 23) (1.49 vs. 0.53 g/g, P < 0.001). Causative variants were found in seven patients with FSGS (TRPC6, WT1, ACTN4, and INF2 in 3, 2, 1, and 1 patient, respectively): all gene variants were in genes manifesting autosomal dominant inheritance mode. The proportion of the perihilar variant was significantly higher in the genetic FSGS patients than in the non-genetic FSGS patients (4/7 vs. 0/7, P < 0.05). Kaplan-Meier analysis showed that the renal survival rate after ASP diagnosis was significantly lower in the genetic FSGS patients than in the non-genetic FSGS and the MGA patients (P < 0.001)., Conclusions: UP/C was a simple and useful predictive parameter for the diagnosis of FSGS. APS without nephrotic syndrome at onset may be associated with autosomal dominant causes of FSGS, especially in those with the perihilar variant., (© 2022. Japanese Society of Nephrology.)

Background: Minimal change disease (MCD) is characterized by a nephrotic syndrome usually steroid-sensitive and a high incidence of relapse of proteinuria. Previous cohort studies have reported conflicting results regarding the association between the time to remission and incidence of relapse., Methods: This multicenter prospective cohort study included 102 adult patients with steroid-sensitive MCD or focal segmental glomerulosclerosis from a 5-year cohort study of primary nephrotic syndrome, the Japan Nephrotic Syndrome Cohort Study, who achieved remission of proteinuria within 2 months of immunosuppressive therapy (IST). The association between the time to remission of proteinuria after immunosuppressive therapy and incidence of relapse was assessed using Cox proportional hazards models adjusted for clinically relevant factors., Results: Remission was observed at 3-7, 8-14, 15-21, 22-28, and 30-56 days after initiation of immunosuppressive therapy in 17 (16.7%), 37 (36.3%), 21 (20.6%), 13 (12.7%), and 14 (13.7%) patients, respectively. During a median observation period of 2.3 years after the end of the 2nd month after initiation of immunosuppressive therapy, 46 (45.1%) patients relapsed. The time to remission was associated with the incidence of relapse in an inverse U-shaped pattern (multivariable-adjusted hazard ratios [95% confidence intervals] of the time to remission of 3-7, 8-14, 15-21, 22-28, 30-56 days: 1.00 [reference], 1.76 [0.56, 5.51], 6.06 [1.85, 19.80], 5.46 [1.44, 20.64], and 2.19 [0.52, 9.30], respectively)., Conclusion: The time to remission was identified as a significant predictor of relapse in steroid-sensitive patients., (© 2022. The Author(s) under exclusive licence to Italian Society of Nephrology.)

We herein report a 43-year-old woman with Buerger's disease who presented with nephrotic syndrome, renal dysfunction, and mild hypertension. A kidney biopsy revealed focal segmental glomerulosclerosis (FSGS), but there were no findings associated with frequent secondary FSGS or a history of long-term hypertension. A small focal renal infarction was seen on 99m Tc-dimercaptosuccinic acid renal scintigraphy, suggesting that FSGS was due to renal microinfarction associated with Buerger's disease. After the commencement of angiotensin-converting enzyme inhibitor therapy, the hypertension immediately improved, along with significant attenuation of proteinuria. Renal ischemia by vasoconstriction of the glomerular efferent arterioles in association with Buerger's disease may result in glomerular hyperfiltration followed by FSGS.

Although bisphosphonates are well known to cause kidney disease, there are very few published cases of focal segmental glomerulosclerosis (FSGS) following treatment with minodronate. Here we report the case of an 86-year-old woman who developed acute kidney injury and nephrotic syndrome after receiving monthly oral minodronate for 24 months. Kidney biopsy revealed cellular variant FSGS. Treatment was initiated with the discontinuation of minodronate followed by intravenous methylprednisolone pulse and prednisolone at 35 mg/day. Subsequently, the patient's renal function gradually worsened, requiring initiation of hemodialysis. However, renal function and proteinuria improved markedly and hemodialysis was withdrawn 1 month after the initiation of steroid therapy. This is, to our knowledge, the first published case of FSGS induced by long-term use of minodronate, and also the first case of cellular variant FSGS induced by bisphosphonates although collapsing variant of FSGS is commonly caused by bisphosphonates. Our study indicates that patients on bisphosphonates should be closely monitored for proteinuria and renal impairment, regardless of the type of bisphosphonate., (© 2021. Japanese Society of Nephrology.)

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., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Purpose: We aimed to evaluate therapeutic response and long-term renal outcomes of childhood idiopathic steroid-resistant nephrotic syndrome (iSRNS)., Methods: We retrospectively reviewed treatment regimens, especially calcineurin inhibitor (CNI), pathologic diagnoses, and long-term renal outcomes of iSRNS patients for 30 years., Results: Of 516 patients with idiopathic NS, 52 (10.1%) had iSRNS. Renal biopsies from 48 patients showed minimal change disease (MCD) in 23 (47.9%), focal segmental glomerulosclerosis in 24 (50.0%), and mesangioproliferative glomerulonephritis in 1 (2.1%). The median follow-up period was 66.5 (range, 4-275) months, and 90.4% of them were treated with a CNI. CNI induced remission in 70.2% within 50.4 ± 43.5 days. Of the patients with MCD and focal segmental glomerular sclerosis (FSGS), 86.4% (19/22) and 45.0% (9/20) (p = 0.005) responded to CNI, respectively. Mean time until remission after using CNI was longer with FSGS (90.4 ± 54.0 days) than with MCD (29.6 ± 26.3 days) (p = 0.010). CNI-responsive patients with FSGS or MCD showed preserved renal function, and CNI nonresponsive MCD patients also showed preserved renal function during follow-up. However, end-stage renal disease (ESRD) progressed in 8 out of 11 patients with FSGS nonresponsive to the CNI for an average of 44.9 ± 18.4 months after diagnosis., Conclusion: Different response rates and times for remission were achieved with the CNI according to the pathology of iSRNS. All MCD patients regardless of CNI response and all CNI-responsive patients with FSGS showed excellent renal outcomes, while almost all FSGS patients nonresponsive to CNI eventually progressed to ESRD., (© 2021 S. Karger AG, Basel.)

Despite the progress made in treating bipolar and unipolar affective disorders, lithium carbonate is still a common drug in psychiatric practice. Lithium-related renal side effects include nephrogenic diabetes insipidus, chronic tubulointerstitial nephropathy, and acute kidney injury (AKI). Nephrotic syndrome (NS) is an uncommon but severe complication of lithium treatment. We present a 49-year-old female treated with lithium carbonate due to a recurrent depressive disorder who developed NS during this therapy. NS spontaneously remitted after the drug withdrawal. Since her lithium serum levels were within the recommended values, we performed a retrospective analysis of lithium-induced NS cases trying to determine causes predisposing to the NS development, underlying histopathology, and preservation or irreversible loss of kidney function. This analysis revealed that in lithium-induced NS with AKI, lithium serum level was the key determinant of AKI development (the β coefficient = 0.8499 with a confidence interval ranging from 0.7452 to 0.9546 and p value < 0.0001). In these cases, the underlying pathology was mainly minimal change disease (MCD), which was quickly reversible upon the drug withdrawal. The development of chronic kidney disease (CKD) seemed to be associated with lithium therapy duration. However, the multiple regression analysis for CKD as the dependent variable showed that the decisive factor was focal segmental glomerulosclerosis (FSGS) as the underlying pathology (the β coefficient = 0.7866 with a confidence interval ranging from 0.600 to 0.9704 and the p value < 0.0001). Thus, we conclude that in lithium-induced NS/AKI, serum lithium levels contribute to these complications, while FSGS lesions are responsible for CKD's disease progression., (© 2021 John Wiley & Sons, Ltd.)

Focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) are common forms of idiopathic nephrotic syndrome. The causes of these diseases are incompletely understood, but the response of patients to immunosuppressive therapies suggests that their pathogenesis is at least in part immune mediated. Preclinical and clinical research indicates that activation of the classical pathway of complement contributes to glomerular injury in FSGS. Glomerular IgM deposits are also prominent in some patients, raising the possibility that IgM is a trigger of classical pathway activation. In the present study, we examined the pattern of complement activation in the glomeruli and plasma of patients with nephrotic syndrome. We also tested whether patients with FSGS and MCD have elevated levels of natural IgM reactive with epitopes on glomerular endothelial cells and cardiolipin. We found evidence of classical pathway activation in patients with idiopathic nephrotic syndrome compared with healthy control subjects. We also detected higher levels of self-reactive IgM to both targets. Based on these results, IgM and classical pathway activation may contribute to disease pathogenesis in some patients with FSGS and MCD. NEW & NOTEWORTHY IgM is detected in biopsies from some patients with nephrotic syndrome, although this has been attributed to passive trapping of the protein. We found, however, that IgM colocalizes with complement activation fragments in some glomeruli. We also found that affected patients had higher levels of IgM reactive to glomerular endothelial cell epitopes. Thus, IgM activates the complement system in the glomeruli of some patients with nephrotic syndrome and may contribute to injury.

There are an increasing number of reports on the safe use of rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, in pregnant women with hematological malignancies or refractory autoimmune diseases. In 2014, the use of RTX for patients with complicated steroid-dependent nephrotic syndrome (SDNS) was approved in Japan. We herein report a woman with childhood-onset complicated SDNS due to focal and segmental glomerulosclerosis, who had two successful pregnancies while receiving RTX maintenance therapy. No adverse complications were observed during the pregnancies, and she delivered healthy newborns. This case suggested that RTX may be used safely in pregnant women complicated with SDNS.

Background: APOL1 high-risk genotypes (HRG) are associated with increased risk of kidney disease in individuals of African ancestry. We analyzed the effects of APOL1 risk variants on an ethnically diverse Brazilian pediatric nephrotic syndrome (NS) cohort., Methods: Multicenter study including 318 NS patients, categorized as progressors to advanced CKD [estimated glomerular filtration rate (eGFR)] < 30 mL/min/1.73 m 2 ] and slow/non-progressors (eGFR > 30 mL/min/1.73 m 2 through the study). We employed Cox regression with progression time as the outcome and APOL1 genotype as the independent variable. We tested this association in the entire cohort and three subgroups; (1) focal segmental glomerulosclerosis (FSGS), (2) steroid-resistant NS (SRNS), and (3) those who underwent kidney biopsy., Results: Nineteen patients (6%) had an HRG. Of these, 47% were self-reported White. Patients with HRG manifested NS at older ages and presented higher frequencies of FSGS and SRNS. HRG patients progressed to advanced CKD more often than low-risk-genotype (LRG) children in the whole NS cohort (p = 0.001) and the three subgroups. In SRNS and biopsied patients, a single risk variant was associated with trends of higher CKD progression risk., Conclusions: Novel discoveries include a substantial prevalence of HRG among patients self-reported White, worse kidney outcomes in HRG versus LRG children in the FSGS subgroup, and a trend of higher CKD progression risk associated with a single risk variant in the SRNS cohort. These findings suggest APOL1-associated NS extends beyond patients self-reported non-White, the HRG effect is independent of FSGS, and a single risk variant may have a detrimental impact in children with NS.

Like many pediatric chronic health conditions, idiopathic childhood onset nephrotic syndrome (iCONS) and late effects of iCONS medical management may continue to impact the affected population in adulthood. Approximately 15% of adult survivors of steroid-sensitive iCONS continue to relapse. Long-term kidney health is associated with steroid response patterns as well as pathology findings of FSGS, tubulointerstitial fibrosis, tubular atrophy, and global glomerulosclerosis. Long-term cardiovascular disease burden is largely unknown in adult survivors, but risk factors starting in childhood, including hypertension, dyslipidemia, and obesity, are common in iCONS. Reproductive health concerns, including azo-/oligospermia and successful pregnancies, are largely related to prior exposure to cytotoxic therapies. Additional investigations are needed to complete the assessment and initiate the mitigation of the late effects of treatment-sensitive and treatment-resistant iCONS.

Glomerular kidney disease causing nephrotic syndrome is a complex systemic disorder and is associated with significant morbidity in affected patient populations. Despite its clinical relevance, well-established models are largely missing to further elucidate the implications of uncontrolled urinary protein loss. To overcome this limitation, we generated a novel, inducible, podocyte-specific transgenic mouse model ( Epb41l5 fl/fl *Nphs1-rtTA-3G*tetOCre ), developing nephrotic syndrome in adult mice. Animals were comprehensively characterized, including microbiome analysis and multiplexed immunofluorescence imaging. Induced knockout mice developed a phenotype consistent with focal segmental glomerular sclerosis (FSGS). Although these mice showed hallmark features of severe nephrotic syndrome (including proteinuria, hypoalbuminemia and dyslipidemia), they did not exhibit overt chronic kidney disease (CKD) phenotypes. Analysis of the gut microbiome demonstrated distinct dysbiosis and highly significant enrichment of the Alistipes genus. Moreover, Epb41l5 -deficient mice developed marked organ pathologies, including extramedullary hematopoiesis of the spleen. Multiplex immunofluorescence imaging demonstrated red pulp macrophage proliferation and mTOR activation as driving factors of hematopoietic niche expansion. Thus, this novel mouse model for adult-onset nephrotic syndrome reveals the significant impact of proteinuria on extra-renal manifestations, demonstrating the versatility of this model for nephrotic syndrome-related research.

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are prescribed as conservative or adjunctive therapies for adult idiopathic nephrotic syndrome. However, studies on real-world practice patterns are scarce. This study aimed to examine the prevalence and incidence of ACEI/ARB prescription and their associated factors. This nationwide cohort study included adult Japanese patients with idiopathic nephrotic syndrome including minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS), and others. The outcomes were the prevalence of ACEI/ARB prescription at baseline (date of renal biopsy or date of immunosuppressant initiation) and at 2 months after baseline. Of the 326 eligible patients, 122 (37.4%) had already been prescribed ACEIs/ARBs. Of the remaining 204 patients, 67 (32.7%) were newly prescribed within the 2-month period. MN/FSGS (vs. MCD, adjusted odds ratio [AOR]: 4.96 [95% confidence interval {CI} 2.53-9.72] and 3.95 [95% CI 1.61-9.66], respectively), higher age (per 1-yr increase, AOR: 1.02 [95% CI 1.00-1.04]), other hypertensive agents (AOR: 2.18 [95% CI 1.21-3.92]), antidiabetic drug (AOR: 6.57 [95% CI 1.77-24.4]) were associated with a higher prevalence of ACEI/ARB prescription. MN (vs. MCD, AOR: 6.00 [95% CI 2.57-14.0]) and higher baseline systolic blood pressure (SBP) (per 10-mmHg increase, AOR: 1.36 [95% CI 1.09-1.70]) were associated with a higher incidence of ACEI/ARB prescription. On average, incidence of ACEI/ARB prescription increased from 19.2% to 40.8% as baseline SBP increased from 100 to 140 mmHg. Thus, Japanese nephrologists are likely to prescribe ACEIs/ARBs for nephrotic patients with MN or high baseline SBP, even below the hypertensive range., (© 2021 The Authors. The Journal of Clinical Hypertension published by Wiley Periodicals LLC.)

Schimke immuno-osseous dysplasia (SIOD) is a rare autosomal recessive inherited disorder that is caused by the SMARCAL1 mutation. The phenotype can vary from mild to severe on the basis of the patient's age at onset. Herein, we report the case of a 14-year-old Chinese boy who presented with short stature, focal segmental glomerulosclerosis (FSGS), and facial dysmorphism. Genetic analysis revealed two compound heterozygous missense mutations, including a well-known mutation (c.1933C>T, p.R645C) and a novel mutation (c.2479G>A, p.V827M) in the SMARCAL1 gene, which were inherited from his parents. In silico analyses showed that the c.2479G>A (p.V827M) variant affects a highly conserved residue within the ATPase catalytic domain. Finally, we established the diagnosis of mild SIOD and treated the patient with diuretics and angiotensin receptor blockers. This report expands the mutational spectrum of SMARCAL1 and reinforces the importance of a detailed clinical evaluation, molecular detection, and appropriate genetic counseling.

Nephrotic syndrome represents the clinical situation characterized by presence of massive proteinuria and low serum protein caused by a variety of diseases, including minimal change nephrotic syndrome (MCNS), focal segmental glomerulosclerosis (FSGS) and membranous glomerulonephropathy. Differentiating between diagnoses requires invasive renal biopsies in general. Even with the biopsy, we encounter difficulties to differentiate MCNS and FSGS in some cases. There is no other better option currently available for the diagnosis other than renal biopsy. MicroRNAs (miRNAs) are no-coding RNAs of approximately 20 nucleotides in length, which regulate target genes in the post-transcriptional processes and have essential roles in many diseases. MiRNAs in serum and urine have been shown as non-invasive biomarkers in multiple diseases, including renal diseases. In this article, we summarize the current knowledge of miRNAs as the promising biomarkers for nephrotic syndrome.

Nephrotic syndrome is one cause of end-stage kidney disease. Because edema is a common presenting feature and hypertension and dyslipidemia are often present in nephrotic syndrome, it is important for the primary care physician to suspect this entity. Common causes in adults include diabetic nephropathy, focal segmental glomerulosclerosis, and membranous nephropathy. In adults, many primary causes are due to an underlying disease. A cause of the nephrotic syndrome should be established with serologic workup and renal consultation. Renal biopsy is necessary in those with an unknown cause to or classify disease. Treatment focuses on symptoms, complications, and the primary cause., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Although many pediatric nephrologists consider focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) as separate clinical entities, whether the initial histology could affect clinical courses in children with steroid-resistant nephrotic syndrome (SRNS) suspected of having an immune-based etiology remains unknown, especially for long-term outcomes., Methods: We retrospectively reviewed long-term outcomes (> 3 years; median follow-up, 9.1 years) of 21 children with initial SRNS (FSGS, N = 9; MCD, N = 12) who achieved complete remission with immunosuppressive agents, including cyclosporine., Results: At NS onset, incidence of acute kidney injury (67% vs. 8%, P < 0.05) and proportion of patients with non-selective proteinuria (56% vs. 0%, P < 0.01) were significantly higher in the FSGS group than the MCD group. Furthermore, median days until complete remission after treatment was significantly longer in the FSGS group than the MCD group (116 days vs. 45 days, P < 0.001). Although subsequent biopsy histology of the 12 patients in the MCD group was still identical in all MCD, three of nine patients in the FSGS group were reclassified from FSGS to MCD at second biopsy. At last visit, all patients maintained complete remission, and none developed chronic kidney disease., Conclusions: Initial presentation in the FSGS group was characterized by more severe clinical manifestations than the MCD group. If complete remission is achieved, FSGS and MCD in children with immune-mediated SRNS may constitute a single disease spectrum because the long-term outcomes are favorable, irrespective of initial histology.

Focal segmental glomerulosclerosis (FSGS) is a common cause of steroid-resistant nephrotic syndrome. Spontaneous remission of FSGS is rare and steroid-resistant FSGS frequently progresses to renal failure. Many inheritable forms of FSGS have been described, caused by mutations in proteins that are important for podocyte function. Here, we show that a basic leucine zipper transcription factor, MafB, protects against FSGS. MAFB expression was found to be decreased in the podocytes of patients with FSGS. Moreover, conditional podocyte-specific MafB-knockout mice developed FSGS with massive proteinuria accompanied by depletion of the slit diaphragm-related proteins (Nphs1 and Magi2), and the podocyte-specific transcription factor Tcf21. These findings indicate that MafB plays a crucial role in the pathogenesis of FSGS. Consistent with this, adriamycin-induced FSGS and attendant proteinuria were ameliorated by MafB overexpression in the podocytes of MafB podocyte-specific transgenic mice. Thus, MafB could be a new therapeutic target for FSGS., (Copyright © 2020 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

We present a case with a rare variant of glomerulonephritis, IgM nephropathy, which occurs mainly with nephrotic syndrome. The clinical features of this variant of kidney damage are characterized; the pathogenetic and the transformation of this form of nephritis into focal segmental glomerulosclerosis are discussed. The development of severe nephrotic syndrome at the beginning of the disease, the formation of secondary steroid resistance have confirmed this hypothesis and have justified the treatment with cyclosporin A aimed at the recovery of the function of the podocyte with remission of nephritis.