Rituximab therapy for refractory steroid-resistant nephrotic syndrome in children

Incidence and risk factors for acute kidney injury in children with nephrotic syndrome: a meta-analysis

Background

Nephrotic syndrome (NS) is a prevalent kidney disease in children. Acute kidney injury (AKI) is a severe complication of NS and has the potential to be life-threatening.

Objective

The aim of this study was to analyze the prevalence and risk factors of AKI in children with NS, and to provide an evidence-based medical basis for the early identification of high-risk children in the clinic.

Methods

A comprehensive search was conducted in publicly available databases, namely PubMed, Embase, Web of Science, Scopus, and the Cochrane Library, covering the period from the inception of each database until May 2024. The analysis involved examining basic characteristics (age, sex), the concomitant diseases (hypertension, infections), NS disease characteristics (steroid susceptibility classification, pathologic classification), laboratory test (e.g., serum albumin), and the use of nephrotoxic drugs. Traditional and network meta-analyses were performed for analysis.

Results

A total of 11 studies were included in the analysis, revealing an incidence of AKI of 29% (95% CI: 23%-37%). The analysis of factors indicated that the age of NS onset [standardized mean difference (SMD): 0.31; 95% confidence interval (CI): 0.08, 0.54; p = 0.009], sex [odds ratio (OR): 1.49; 95% CI: 1.03, 2.16; p = 0.035], serum albumin level (SMD: -0.43; 95% CI: -0.85, -0.02; p = 0.041), response to steroid treatment (OR: 0.52; 95% CI: 0.33, 0.80; p = 0.003), infection (OR: 3.60; 95% CI: 1.91, 6.78; p < 0.001), hypertension (OR: 4.02; 95% CI: 2.94, 5.51; p < 0.001), and nephrotoxic drug application (OR: 4.43; 95% CI: 1.86, 10.53; p = 0.001), were all significantly associated with the incidence of AKI. Furthermore, the results of the network meta-analysis suggested that the pathologic type of minor glomerular abnormalities (MGA)/diffuse mesangial proliferation (DMP), the type of infrequent relapses (IFRNS)/steroid-sensitive NS (SSNS), and the use of diuretic medications were associated with a relatively low risk of AKI occurrence.

Conclusion

Factors upon admission of children with NS are associated with the onset of AKI. Emphasis should be placed on populations with a heightened risk of AKI in clinical practice. Further research is warranted to confirm the findings due to the limitations of this study.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024571170, PROSPERO (CRD42024571170).

An international, multi-center study evaluated rituximab therapy in childhood steroid-resistant nephrotic syndrome

The efficacy and safety of rituximab in childhood steroid-resistant nephrotic syndrome (SRNS) remains unclear. Therefore, we conducted a retrospective cohort study at 28 pediatric nephrology centers from 19 countries in Asia, Europe, North America and Oceania to evaluate this. Children with SRNS treated with rituximab were analyzed according to the duration of calcineurin inhibitors (CNIs) treatment before rituximab [6 months or more (CNI-resistant) and under 6 months]. Primary outcome was complete/partial remission (CR/PR) as defined by IPNA/KDIGO guidelines. Secondary outcomes included kidney failure and adverse events. Two-hundred-forty-six children (mean age, 6.9 years; 136 boys; 57% focal segmental glomerulosclerosis, FSGS) were followed a median of 32.4 months after rituximab. All patients were in non-remission before rituximab. (146 and 100 children received CNIs for 6 month or more or under 6 months before rituximab, respectively). In patients with CNI-resistant SRNS, the remission rates (CR/PR) at 3-, 6-, 12- and 24-months were 26% (95% confidence interval 19.3-34.1), 35.6% (28.0-44.0), 35.1% (27.2-43.8) and 39.1% (29.2-49.9), respectively. Twenty-five patients were in PR at 12-months, of which 22 had over 50% reduction in proteinuria from baseline. The remission rates among children treated with CNIs under 6 months before rituximab were 42% (32.3-52.3), 52% (41.8-62.0), 54% (44.3-64.5) and 60% (47.6-71.3) at 3-, 6-, 12-, and 24-months. Upon Kaplan-Meier analysis, non-remission and PR at 12-months after rituximab, compared to CR, were associated with significantly worse kidney survival. Adverse events occurred in 30.5% and most were mild. Thus, rituximab enhances remission in a subset of children with SRNS, is generally safe and CR following rituximab is associated with favorable kidney outcome.

Kidney outcomes in children with primary focal segmental glomerulosclerosis from a low- and middle- income country

BACKGROUND

Limited data exists regarding the clinical course and outcomes of children with primary focal segmental glomerulosclerosis (FSGS) from low- and middle- income countries.

METHODS

Children aged 1-18 years with biopsy-proven primary FSGS followed from January 2010-June 2023 in a tertiary-care center were enrolled and their clinical profile, histological characteristics, kidney outcomes, and predictors of adverse outcomes were determined.

RESULTS

Over 13 years, 73 (54.8% boys) children with median (IQR) age at FSGS diagnosis 6.7 (3,10) years were recruited and followed up for median 4 (2.5,8) years. FSGS-not otherwise specified (NOS) was the most common histological subtype, in 64 (87.6%) children, followed by collapsing variant in 5 (6.8%) children. At last follow-up, 43 (58.9%), 2 (2.7%) and 28 (38.3%) children were in complete remission (CR), partial remission (PR), and no remission (NR) respectively. Calcineurin inhibitors led to CR or PR in 39 (62%) children. Overall, 21 (28.7%) children progressed to chronic kidney disease (CKD) stage 2-5 (19 from NR vs. 2 from PR group; p = 0.03); with 41% of those NR at 12 months progressing to CKD 4-5 by last follow-up. On multivariable analysis, collapsing variant [adjusted HR 2.5 (95%CI 1.5, 4.17), p = 0.001] and segmental sclerosis > 25% [aHR 9.9 (95%CI 2.2, 45.2), p = 0.003] predicted kidney disease progression.

CONCLUSIONS

In children with FSGS, response to immunosuppression predicts kidney survival as evidenced by nil to lower progression to CKD 2-5 by median follow-up of 4 (2.5,8) years in children with CR and PR, compared to those with no remission at 12 months from diagnosis. Segmental sclerosis > 25% and collapsing variant predicted progression to advanced CKD.

Combination of rituximab and low-dose glucocorticoids for idiopathic refractory nephrotic syndrome with MCD/FSGS: a single-center prospective cohort study

BACKGROUND

The treatment of idiopathic refractory nephrotic syndrome (IRNS) remains a difficult problem in clinical practice. This study aims to determine the efficacy and safety of combining low-dose glucocorticoids with rituximab in IRNS treatment.

METHODS

This prospective, single-center cohort study enrolled 60 patients who were diagnosed with refractory IRNS with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS) and treated at First Affiliated Hospital of Sun Yat-sen University. All patients received a treatment regimen consisting of rituximab (375 mg/m2/week × 4) and low-dose glucocorticoids.

RESULTS

46 complete remissions and 4 partial remissions were observed within 6 months of treatment. Within 12 months of treatment, 48 patients achieved complete remission, and 4 achieved partial remission. The complete remission rate for steroid-dependent/frequently relapsing nephrotic syndrome was significantly higher than that for steroid-resistant nephrotic syndrome (88.24% vs. 33.33%, p < .01). Following up for 12 months, 16 patients relapsed, accounting for 30.76% of the total, with a mean time to relapse of 10.97 months. Compared with baseline data, 24-hour urine protein quantification, total cholesterol and triglycerides significantly decreased, while serum albumin, globulin and IgG significantly increased at 12 months after treatment. All follow-ups were without serious adverse events. Twenty-four patients experienced infusion-related adverse reactions, which could be relieved by slowing down the infusion rate or suspending the infusion. Nine patients experienced infection-related adverse reactions; six of them were relieved with antibiotic treatment, and 3 patients were controlled by symptomatic treatment.

CONCLUSIONS

Rituximab combined low-dose glucocorticoids therapy is effective and safe in idiopathic refractory nephrotic syndrome.

Clinical characteristics and prognosis of steroid-resistant nephrotic syndrome in children: a multi-center retrospective study

BACKGROUND

This study investigated the factors influencing the prognosis of children with steroid-resistant nephrotic syndrome (SRNS) in patients from the Guangxi region.

METHODS

We retrospectively analyzed clinical and pathological data of 279 patients with SRNS from six tertiary hospitals in Guangxi. Clinical data were compared between initial (I-SRNS) and secondary (S-SRNS) steroid resistance subgroups and Cox regression analysis was used to determine risk factors for chronic kidney disease (CKD) and CKD stage 5 (CKD5) in patients with SRNS.

RESULTS

The median age of onset was 54 months. Thirty-three patients had extra-kidney manifestations. Fifty-two, 24, 57, 33, and 41 patients had hypertension, acute kidney injury, vitamin D deficiency, high intraocular pressure, and dwarfism, respectively. One hundred eighty-two and 92 patients had I-SRNS and S-SRNS, respectively. There were significant differences in sex, ethnicity, family history, incidence of hematuria, clinical classification, efficacy of immune agents, and prognosis between groups (P < 0.05). Among the 279 cases of SRNS, 239 had normal kidney function, 37 developed CKD, and 16 had CKD5. An increase in serum creatinine level (HR = 1.003) was significantly associated with CKD in children with SRNS, and effective immunosuppressant therapy decreased the CKD risk (HR = 0.168). Patients with increased serum creatinine levels (HR = 1.003) and acute kidney injury (HR = 4.829) were more likely to progress to CKD5.

CONCLUSIONS

Children with S-SRNS showed a higher response to immunosuppressants than those with I-SRNS. Effective immunosuppressant therapy was found to protect against CKD, whereas increased acute kidney injury was an independent risk factor for CKD5.

Efficacy of rituximab and risk factors for poor prognosis in patients with childhood-onset steroid-resistant nephrotic syndrome: a multicenter study

BACKGROUND

The efficacy of rituximab in steroid-resistant nephrotic syndrome (SRNS) is controversial. We previously reported that rituximab in combination with methylprednisolone pulse therapy (MPT) and immunosuppressants was associated with favorable outcomes. We determined risk factors for poor response following rituximab treatment, which remains unknown.

METHODS

This retrospective study included 45 patients with childhood-onset SRNS treated with rituximab across four pediatric kidney facilities. Treatment effects were categorized as complete remission (CR), partial remission (PR), and no remission (NR) at one year after rituximab treatment. The primary outcome was the rate of CR, PR, and NR. Risk factors for non-CR were calculated with multivariate logistic regression. Adverse events and the relationship between disease status at one year and long-term prognosis were also evaluated.

RESULTS

The rates of CR, PR, and NR at one year were 69%, 24%, and 7%, respectively. The median time from rituximab administration to CR was 90 days. The median follow-up period after rituximab administration was 7.4 years. In multivariate analysis, significant risk factors for poor response were the pathologic finding of focal segmental glomerular sclerosis and a long interval between SRNS diagnosis and rituximab administration. The rates of CR were 90.3% and 21.4% in patients receiving rituximab within and after 6 months following SRNS diagnosis, respectively (p < 0.001). Five patients developed chronic kidney disease stage G5, including 2 of the 11 patients with PR and all 3 patients with NR, whereas none of the 31 patients with CR developed chronic kidney disease stage G5.

CONCLUSION

Early administration of rituximab in combination with MPT and immunosuppressants might achieve favorable outcomes in patients with SRNS.

Intravenous cyclophosphamide therapy in children with calcineurin inhibitor-resistant steroid-resistant nephrotic syndrome in a resource-limited setting

BACKGROUND

In pediatric steroid-resistant nephrotic syndrome (SRNS), calcineurin inhibitors (CNIs) are recommended as first-line therapy, with efficacy ranging between 60 and 80%, implying a substantial proportion will exhibit CNI resistance. Which alternate immunosuppressive therapy should be used in non-genetic pediatric SRNS exhibiting CNI resistance is especially relevant in low- to middle-income countries (LMIC), where the prohibitive costs of certain drugs such as monoclonal antibodies often determine therapy choice.

METHODS

The primary objective was to assess the efficacy of intravenous cyclophosphamide in a proportion of children aged 1-18 years with CNI-resistant SRNS with a complete response (CR) or partial response (PR) at 6 months from commencement of pulse therapy. The secondary objectives were to assess the proportion and profile of infections and adverse effects.

RESULTS

Of 90 children with idiopathic SRNS presenting between January 2013 and December 2022, 29 (32.2%) had CNI resistance and were enrolled. They were administered monthly intravenous cyclophosphamide pulses (6 pulses). Median (IQR) duration of follow-up was 48 (29.5, 63.5) months. At the end of 6 months of cyclophosphamide therapy, 13 (44.8%) attained CR and 4 (13.8%) attained PR, with an overall cyclophosphamide success rate of 58.6%. The efficacy of intravenous cyclophosphamide was higher in secondary (9/10; 90%) versus primary CNI resistance (8/19; 42.1%) (p = 0.029). Three children (3/29; 10.3%) developed systemic infections within 12 months of initiation of cyclophosphamide therapy, similar to the rate of systemic infections among children receiving CNI for SRNS management (6/41; 14.6%) (p = 0.85).

CONCLUSIONS

It is prudent to try intravenous cyclophosphamide in CNI-resistant SRNS in LMIC, given the reasonable cost and good efficacy rates (58.6%).

Rituximab in combination with cyclosporine and steroid pulse therapy for childhood-onset multidrug-resistant nephrotic syndrome: a multicenter single-arm clinical trial (JSKDC11 trial)

BACKGROUND

Only 80% of children with idiopathic nephrotic syndrome respond well to glucocorticoid therapy. Multidrug-resistant nephrotic syndrome (MRNS) is associated with a poor kidney prognosis. Several retrospective studies have identified rituximab as an effective treatment for MRNS; however, prospective studies are required to assess its efficacy and safety.

METHODS

We conducted a multicenter, non-blinded, single-arm trial to investigate the efficacy and safety of rituximab in patients with childhood-onset MRNS who were resistant to cyclosporine and more than three courses of steroid pulse therapy. The enrolled patients received four 375 mg/m2 doses of rituximab in combination with baseline cyclosporine and steroid pulse therapy. The primary endpoint was a > 50% reduction in the urinary protein/creatinine ratio from baseline on day 169. Complete and partial remissions were also evaluated.

RESULTS

Six patients with childhood-onset MRNS were enrolled. All patients were negative for pathogenic variants of podocyte-related genes. On day 169, five patients (83.3%) showed a > 50% reduction in the urinary protein/creatinine ratio, two patients showed partial remission, and two patients showed complete remission. No deaths occurred and severe adverse events occurred in two patients (infection in one patient and acute kidney injury in one patient). Three patients needed treatment for moderate-to-severe infection.

CONCLUSIONS

The study treatment effectively reduced the urinary protein/creatinine ratio in patients with childhood-onset MRNS. The adverse events in this study were within the expected range; however, attention should be paid to the occurrence of infections.

Quercetin-targeted AKT1 regulates the Raf/MEK/ERK signaling pathway to protect against doxorubicin-induced nephropathy in mice

BACKGROUND

Doxorubicin is an anthracycline antitumor agent commonly used in clinical practice, which has some nephrotoxicity and is often used to establish mouse models of kidney injury for basic medical research. This study will investigate the protective effect of quercetin on renal function in doxorubicin-induced nephropathy mice.

METHODS

C57BL/6 mice were divided into control, model, and quercetin low-, and high-dose groups. Serum and urine were collected to analyze markers of kidney function. H&E staining was used to detect pathological changes in renal tissues. Transmission electron microscopy was performed to observe the ultrastructural changes in renal tissues. Immunohistochemistry was performed to detect the changes of Ang II. RT-qPCR was performed to detect the changes of cytokines. ELISA was used to detect changes in serum inflammatory factors. Molecular docking was performed to verify the targeting relationship between quercetin and AKT1. Western blot was performed to detect Bax, Bcl-2, Cyt-c, AKT1, Raf, MEK, and ERK proteins.

RESULTS

Quercetin could induce the recovery of kidney function in kidney-injured mice; H&E results showed that kidney tissue damage and tissue fibrosis were reduced in kidney-injured mice under quercetin. The mitochondrial swollen structure was destroyed by doxorubicin, while the mitochondrial structure was restored under quercetin. The levels of abnormal apoptotic proteins Bax and Bcl-2 were regulated to normal by quercetin. The high expression of Ang II caused by doxorubicin was down-regulated by quercetin. Abnormal inflammatory factors caused by doxorubicin were reversed by quercetin. Western blot experiments showed that quercetin regulated the protein levels of AKT1 and Raf/MEK/ERK and inhibited the detrimental effects of doxorubicin.

CONCLUSION

Quercetin may mitigate doxorubicin-induced kidney injury in mice by regulating renal cell inflammatory factors and Raf/MEK/ERK signaling pathway through AKT1 to promote recovery of renal function.

Rituximab therapy for childhood onset idiopathic nephrotic syndrome: experience of a Portuguese tertiary center

INTRODUCTION

Rituximab (RTX) is a therapeutic option in pediatric difficult-to-treat idiopathic nephrotic syndrome (NS). We aimed to assess the efficacy and safety of RTX use in these patients.

METHOD

A retrospective study of all patients with idiopathic NS treated with RTX was conducted in a pediatric nephrology division of a tertiary hospital. Demographic, anthropometric, clinical and analytical data were collected prior to treatment and at 6, 12, and 24 months.

RESULTS

Sixteen patients were included (11 males), with a median (25th-75th percentile, P25-P75) age at diagnosis of 2 (2.0-2.8) years. Fifteen were steroid-sensitive and 1 was steroid-resistant and sensitive to cyclosporine. The median age at administration of RTX was 10 (6.3-14.0) years. Throughout a median follow-up time of 2.5 (1.0-3.0) years, 6 (37.5%) patients achieved partial remission and 7 (43.8%) had no relapses and were not taking any immunosuppressants at the 24-month follow-up visit. Regarding complications, 1 patient presented persistent hypogammaglobulinemia. Compared with the 12-month period before RTX, there was a decrease in the median number of relapses at 6 and 12 months [3 (3.0-4.0) vs 0 (0-0.8) and 0.50 (0-1.0), respectively; p = 0.001] and in the daily steroids dose (mg/kg/day) at 6, 12, and 24 months [0.29 (0.15-0.67)vs [0.10 (0.07-0.13); p = 0.001], [0.12 (0.05-0.22); p = 0.005] and [0.07(0.04-0.18); p = 0.021]], respectively. There was also a reduction in the median BMI z score at 24 months [2.11 (0.45-3.70) vs. 2.93 (2.01-3.98); p = 0.049].

CONCLUSION

Our results confirm the efficacy and safety of RTX use in pediatric idiopathic NS and highlight its' potential cardiometabolic benefits.

Current Status Regarding Immunosuppressive Treatment in Patients after Renal Transplantation

Renal transplantation is now the best treatment for end-stage renal failure. To avoid rejection and prolong graft function, organ recipients need immunosuppressive therapy. The immunosuppressive drugs used depends on many factors, including time since transplantation (induction or maintenance), aetiology of the disease, and/or condition of the graft. Immunosuppressive treatment needs to be personalised, and hospitals and clinics have differing protocols and preparations depending on experience. Renal transplant recipient maintenance treatment is mostly based on triple-drug therapy containing calcineurin inhibitors, corticosteroids, and antiproliferative drugs. In addition to the desired effect, the use of immunosuppressive drugs carries risks of certain side effects. Therefore, new immunosuppressive drugs and immunosuppressive protocols are being sought that exert fewer side effects, which could maximise efficacy and reduce toxicity and, in this way, reduce both morbidity and mortality, as well as increase opportunities to modify individual immunosuppression for renal recipients of all ages. The aim of the current review is to describe the classes of immunosuppressive drugs and their mode of action, which are divided by induction and maintenance treatment. An additional aspect of the current review is a description of immune system activity modulation by the drugs used in renal transplant recipients. Complications associated with the use of immunosuppressive drugs and other immunosuppressive treatment options used in kidney transplant recipients have also been described.

Shared genetic risk across different presentations of gene test-negative idiopathic nephrotic syndrome

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.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome

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

T-cell and B-cell repertoire diversity are selectively skewed in children with idiopathic nephrotic syndrome revealed by high-throughput sequencing

BACKGROUND

Clinical studies suggest that the dysfunction of T cells and B cells may play an essential role in the pathogenesis of idiopathic nephrotic syndrome (INS), but laboratory evidence is lacking. Therefore, this study explored T-cell receptor (TCR) and B-cell receptor (BCR) profiling in children with idiopathic nephrotic syndrome.

METHODS

High-throughput sequencing technology was used to profile the TCR and BCR repertoires in children with INS. Peripheral blood was collected from ten INS patients, including five vinculin autoantibody-positive patients and five vinculin autoantibody-negative patients, before and after treatment. TCR and BCR libraries were constructed by 5'-RACE and sequenced by a DNBSEQ-T7 sequencer, and sequence analyses were performed using ReSeqTools, FastP, MiXCR, and VDJtools.

RESULTS

The TRA (T-cell receptor α), TRG (T-cell receptor γ), and IGH (immunoglobulin heavy chain) repertoires of the INS group were occupied by highly abundant clonotypes, whereas small clonotypes occupied the healthy group, especially TRA. A significant increase in the Shannon-Weaver index was observed for the TRA and TRG repertoires after treatment in vinculin autoantibody-negative patients, but a significant increase in the IGH repertoire after treatment was observed in vinculin autoantibody-positive patients. The frequency of some V-J pairs was significantly enriched in steroid-sensitive nephrotic syndrome patients. The usage frequency of the V and J genes was skewed in patients, which seemed not related to immunosuppressive therapy. However, after effective treatment, dynamic changes in the size of the individual clonotype were observed.

CONCLUSION

T-cell and B-cell immunity contribute to the pathogenesis of different INSs. Video: (MP4 99,786 KB).

Changes in Patterns of Infection Associated with Pediatric Idiopathic Nephrotic Syndrome: A Single-Center Experience in Japan

OBJECTIVE

We studied infection rates and risk factors for infection in current patients with idiopathic nephrotic syndrome (INS).

STUDY DESIGN

This retrospective cohort study included the clinical data for children with diagnosed INS in our center between January 2010 and December 2020. The infection rates and risk factors were analyzed.

RESULTS

We enrolled 187 patients, including 85 cases with steroid-dependent/frequently relapsing nephrotic syndrome and 45 with steroid-resistant nephrotic syndrome. Infection was observed a total of 84 times in 55 patients (95.5 per 1000 person-years). Pneumonia was the most common infection (21 cases, 23.9 per 1000 person-years), followed by febrile neutropenia (12 cases, 13.7 per 1000 person-years), whereas peritonitis and bacteremia were observed in only 3 and 2 cases, respectively. The multivariate analyses by logistic regression showed that rituximab treatment was significantly associated with infections in pediatric INS (P = .001). The infection rate during the B-cell-depleted state with immunosuppressants (318 per 1000 person-years) was greater than that with normal B-cell count with immunosuppressants (109 per 1000 person-years) or without immunosuppressants (76 per 1000 person-years).

CONCLUSION

Common infections, such as peritonitis and bacteremia, decreased, whereas infections associated with medication (eg, rituximab) increased. The rate of infection increases during B-cell depletion after treatments with rituximab and other immunosuppressants.

Case Report: Successful treatment of severe pneumocystis carinii pneumonia in a case series of primary nephrotic syndrome after receiving anti-CD20 monoclonal antibody therapy

Rituximab is emerging as a new steroid sparing agent in children with difficult-to-treat nephrotic syndrome due to its ability of depleting CD20-positive B cells. Life-threatening adverse events such as pneumocystis carinii pneumonia may occur even though it seems to be well tolerated. Since rituximab is wildly used in immune-mediated diseases, it is important to manage its severe adverse events. To explore the importance of early diagnosis and treatment of pneumocystis carinii pneumonia in children with primary nephrotic syndrome (PNS) after receiving rituximab therapy, we retrospectively analyzed the clinical data of PNS patients younger than 18 years old with pneumocystis carinii pneumonia who were hospitalized in our center. Clinical features and laboratory test results were retrieved from the electronic medical records. Severe pneumocystis carinii pneumonia occurred in one child with steroid resistant nephrotic syndrome and two with steroid dependent nephrotic syndrome patients after rituximab treatment. These patients were diagnosed in time by metagenomic next-generation sequencing (mNGS) for pathogen detection. Fortunately, all three patients survived after antifungal treatment and achieved complete remission eventually. In conclusion, early diagnosis by using mNGS and timely antifungal treatment is the key to successful management of pneumocystis carinii pneumonia in children with difficult-to-treat PNS.

Combined Methylprednisolone Pulse Therapy plus Rituximab for Treating a Rare Juvenile Steroid-Resistant Nephrotic Syndrome with Cerebral Venous Sinus Thrombosis: A Case Report

Background: Cerebral venous sinus thrombosis (CVST) secondary to nephrotic syndrome (NS) is rarely reported. Additionally, treating steroid-sensitive nephrotic syndrome (SSNS) that changes to steroid resistance (SRNS) is difficult, with many relapses and side effects. Case presentation: A 32-month-old SSNS male child turned into SRNS and developed cerebral venous sinus thrombosis (CVST), a rare complication of NS. As a result of the administration of combined pulse methylprednisolone and IV Rituximab (RTX) therapy, the patient showed marked improvement, the results of urine analysis were remarkably improved, and the child started to respond to treatment. Conclusion: Successful treatment of a rare case of juvenile SSNS behaving as SRNS with the development of CVST could be established using combined steroid pulse therapy, Enoxaparin, and the B lymphocytes monoclonal antibodies RTX.

Terapia com Rituximabe para síndrome nefrótica idiopática de início na infância: experiência de um centro terciário português

Resumo Introdução: Rituximabe (RTX) é uma opção terapêutica na síndrome nefrótica (SN) idiopática pediátrica de difícil tratamento. Visamos avaliar eficácia e segurança do uso de RTX nestes pacientes. Método: Realizou-se estudo retrospectivo de todos os pacientes com SN idiopática tratados com RTX, em uma unidade de nefrologia pediátrica de um hospital terciário. Dados demográficos, antropométricos, clínicos e analíticos foram coletados antes do tratamento e aos 6, 12 e 24 meses. Resultados: Incluímos 16 pacientes (11 do sexo masculino), com idade mediana (percentil 25–75, P25–P75) de 2 (2,0–2,8) anos ao diagnóstico. Quinze eram sensíveis a esteroides, e 1 resistente a esteroides e sensível à ciclosporina.A idade mediana na administração do RTX foi 10 (6,3–14,0) anos. Durante um tempo mediano de acompanhamento de 2,5(1,0–3,0) anos, 6 (37,5%) pacientes alcançaram remissão parcial e 7 (43,8%) não tiveram recidivas e não estavam tomando imunossupressor no acompanhamento aos 24 meses. Quanto às complicações,1 paciente apresentou hipogamaglobulinemia persistente. Comparado ao período de12 meses anterior ao RTX, houve diminuição no número mediano de recidivas em 6 e 12 meses [3 (3,0–4,0) vs 0 (0–0,8) e 0,50 (0–1,0), respectivamente; p = 0,001] e na dose diária de esteroides (mg/kg/dia) aos 6, 12 e 24 meses [0,29 (0,15–0,67) >vs [0,10 (0,07–0,13); p = 0,001], [0,12 (0,05–0,22); p = 0,005] e [0,07 (0,04–0,18); p = 0,021], respectivamente. Houve também redução na mediana do escore z do IMC aos 24 meses [2,11 (0,45–3,70) vs 2,93 (2,01–3,98);p = 0,049]. Conclusões: Nossos resultados confirmam a eficácia e segurança do uso de RTX em SN idiopática pediátrica, destacando seus potenciais benefícios cardiometabólicos.

Rituximab as induction therapy in pediatric kidney transplantation: A single-center experience in four patients

BACKGROUND

The anti-CD20 rituximab is often used in the treatment of children with steroid-resistant nephrotic syndrome or EBV-induced post-transplant lymphoproliferative disorder. This single-center series reports the use of rituximab as induction therapy in pediatric kidney transplantation.

METHODS

Four children who received rituximab as induction therapy for kidney transplantation since 2016 were retrospectively analyzed. Clinical and laboratory data were extracted from medical records.

RESULTS

The patients (2 boys and 2 girls) were aged from 6.1 to 11.9 years and were treated with rituximab on the day of the transplantation procedure; all the transplants came from deceased donors. In all patients, rituximab was used because of positive EBV viral loads before kidney transplantation. Viral loads remained undetectable for the first 6 months after the transplantation procedure and remained below the 4.5 log threshold thereafter. After a median follow-up of 2.3 years, none of the patients displayed rejection or de novo donor-specific antibodies; the glomerular filtration rate remained above 70 ml/min/1.73 m² . No post-transplant lymphoproliferative disorder was observed.

CONCLUSION

The results suggest that rituximab can be used as induction therapy to prevent EBV replication and its complications in case of positive viral load prior to kidney transplantation.

Tedavisi zor nefrotik sendromlu çocuklarda rituksimab tedavisi

Amaç: Rituksimab (RTX), tedavisi zor nefrotik sendromlu (sık tekrarlayan, steroide bağımlı ve steroide dirençli) hastalar için kurtarma tedavisi olarak önerilmektedir. Amacımız zor nefrotik sendromlu çocuklarda RTX tedavisinin etkinliğini ve uzun dönem sonuçlarını değerlendirmek ve deneyimlerimizi paylaşmaktır. Gereç ve Yöntem: RTX ile tedavi edilen zor nefrotik sendromlu çocukların tıbbi kayıtları geriye dönük olarak değerlendirildi. Oniki ayda nükssüz sağkalım oranı ve B hücre deplesyonun izlemi değerlendirildi. Bulgular: Çalışmaya 8'i steroide bağımlı (SBNS), 6'sı sık tekrarlayan (STNS) ve 6'sı steroide dirençli nefrotik sendromlu (SDNS) 20 çocuk dahil edildi. RTX tedavisi alan STNS/SBNS hastalarının tedavi öncesi ve sonrası 1 yıllık ortalama nüks sayısı karşılaştırıldı. Ortalama nüks sayısı 2 (1-4)’den 0 (0-1) kez/yıla geriledi. RTX tedavisi sonrası ortalama takip süresi 23 ay (12-59) ve 8 hastada nüks gelişti. RTX tedavisi sonrası nüks eden 5 hastaya, tekrarlayan dozlarda RTX uygulandı. Bu hastalarda, CD19+B hücreleri remisyon sırasında yeniden ortaya çıkarken, hafıza B hücrelerinin deplesyonu devam etti. Sonuç: RTX tedavisi, STNS/SBNS hastalarında remisyon süresini uzattı, ancak SDNS hastalarında etkisiz kaldı. Bu hastalarda remisyonun idamesi için RTX dozunun tekrarlanabileceği ve tekrarlama dozlarının zamanlamasında en iyi hafıza B hücre sayısının yardımcı olabileceği saptandı.

Rituximab Therapy for Adults with Nephrotic Syndromes: Standard Schedules or B Cell-Targeted Therapy?

Rituximab is a chimeric anti-CD20 monoclonal antibody. It acts mainly through complement-dependent cytotoxicity on B cells expressing the CD20 marker. In this review, we analyse the efficacy and possible pitfalls of rituximab to treat nephrotic syndromes by taking into account pharmacological considerations and CD19 marker testing utility. Despite the fact that the drug has been in use for years, efficacy and treatment schedules in adults with nephrotic syndrome are still a matter of debate. Clinical trials have proven the efficacy and safety of rituximab in idiopathic membranous nephropathy. Data from observational studies also showed the efficacy of rituximab in minimal change disease and focal segmental glomerulosclerosis. Rituximab use is now widely recommended by new Kidney Disease Improved Outcome (KDIGO) guidelines in membranous nephropathy and in frequent-relapsing, steroid-dependent minimal change disease or focal segmental glomerulosclerosis. However, rituximab response has a large interindividual variability. One reason could be that rituximab is lost in the urine at a higher extent in patients with nonselective nephrotic proteinuria, exposing patients to different rituximab plasma levels. Moreover, the association between CD19+ levels and clinical response or relapses is not always present, making the use of this marker in clinical practice complex. High resolution flow cytometry has increased the capability of detecting residual CD19+ B cells. Moreover, it can identify specific B-cell subsets (including IgG-switched memory B cells), which can repopulate at different rates. Its wider use could become a useful tool for better understanding reasons of rituximab failure or avoiding unnecessary retreatments.

The role of the immune system in idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (INS) in children is characterized by massive proteinuria and hypoalbuminemia and usually responds well to steroids. However, relapses are frequent, which can require multi-drug therapy with deleterious long-term side effects. In the last decades, different hypotheses on molecular mechanisms underlying INS have been proposed and several lines of evidences strongly indicate a crucial role of the immune system in the pathogenesis of non-genetic INS. INS is traditionally considered a T-cell-mediated disorder triggered by a circulating factor, which causes the impairment of the glomerular filtration barrier and subsequent proteinuria. Additionally, the imbalance between Th17/Tregs as well as Th2/Th1 has been implicated in the pathomechanism of INS. Interestingly, B-cells have gained attention, since rituximab, an anti-CD20 antibody demonstrated a good therapeutic response in the treatment of INS. Finally, recent findings indicate that even podocytes can act as antigen-presenting cells under inflammatory stimuli and play a direct role in activating cellular pathways that cause proteinuria. Even though our knowledge on the underlying mechanisms of INS is still incomplete, it became clear that instead of a traditionally implicated cell subset or one particular molecule as a causative factor for INS, a multi-step control system including soluble factors, immune cells, and podocytes is necessary to prevent the occurrence of INS. This present review aims to provide an overview of the current knowledge on this topic, since advances in our understanding of the immunopathogenesis of INS may help drive new tailored therapeutic approaches forward.

Use of rituximab in paediatric nephrology

Rituximab is a chimeric monoclonal antibody capable of depleting B cell populations by targeting the CD20 antigen expressed on the cell surface. Its use in oncology, initially in B cell lymphoma and post-transplant lymphoproliferative disorders, predates its current utility in various fields of medicine wherein it has become one of the safest and most effective antibody-based therapies. It was subsequently found to be effective for rheumatological conditions such as rheumatoid arthritis and antineutrophil cytoplasmic antibody-associated vasculitis. Over the past decade, rituximab has generated a lot of interest in nephrology and has become an emerging or accepted therapy for multiple renal conditions, including systemic lupus erythematosus, lupus nephritis, vasculitis, nephrotic syndrome and in different scenarios before and after kidney transplantation. This review outlines its current use in paediatric nephrology practice, focusing on the knowledge required for general paediatricians who may be caring for children prescribed this medication and reviewing them on a shared care basis.

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 T_reg 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.

Steroid-resistant Nephrotic Syndrome in Children: A Mini-review on Genetic Mechanisms, Predictive Biomarkers and Pharmacotherapy Strategies

Steroid-resistant nephrotic syndrome (SRNS) constitutes the second most frequent cause of chronic kidney disease in childhood. The etiology of SRNS remains largely unknown and no standardized treatment exists. Recent advances in genomics have helped to build understanding of the molecular mechanisms and pathogenesis of the disease. The genetic polymorphisms in genes encoding proteins which are involved in the pharmacokinetics and pharmacodynamics of glucocorticoids (GCs) partially account for the different responses between patients with nephrotic syndrome. More importantly, single-gene causation in podocytes-associated proteins was found in approximately 30% of SRNS patients. Some potential biomarkers have been tested for their abilities to discriminate against pediatric patients who are sensitive to GCs treatment and patients who are resistant to the same therapy. This article reviews the recent findings on genetic mechanisms, predictive biomarkers and current therapies for SRNS with the goal to improve the management of children with this syndrome.

Current understandings in treating children with steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatric nephrologists. SRNS is viewed as a heterogeneous disease entity including immune-based and monogenic aetiologies. Because SRNS is rare, treatment strategies are individualized and vary among centres of expertise. Calcineurin inhibitors (CNI) have been effectively used to induce remission in patients with immune-based SRNS; however, there is still no consensus on treating children who become either CNI-dependent or CNI-resistant. Rituximab is a steroid-sparing agent for patients with steroid-sensitive nephrotic syndrome, but its efficacy in SRNS is controversial. Recently, several novel monoclonal antibodies are emerging as treatment option, but their efficacy remains to be seen. Non-immune therapies, such as angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, have been proven efficacious in children with SRNS and are recommended as adjuvant agents. This review summarizes and discusses our current understandings in treating children with idiopathic SRNS.

Baseline characteristics and long-term outcomes of steroid-resistant nephrotic syndrome in children: impact of initial kidney histology

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.

Mild electrical stimulation with heat shock attenuates renal pathology in adriamycin-induced nephrotic syndrome mouse model

Nephrotic syndrome (NS) is a renal disorder that is characterized by massive proteinuria, hypoalbuminemia and edema. One of the main causes of NS is focal segmental glomerulosclerosis (FSGS), which has extremely poor prognosis. Although steroids and immunosuppressants are the first line of treatment, some FSGS cases are refractory, prompting the need to find new therapeutic strategies. We have previously demonstrated that an optimized combination treatment of mild electrical stimulation (MES) and heat shock (HS) has several biological benefits including the amelioration of the pathologies of the genetic renal disorder Alport syndrome. Here, we investigated the effect of MES + HS on adriamycin (ADR)-induced NS mouse model. MES + HS suppressed proteinuria and glomerulosclerosis induced by ADR. The expressions of pro-inflammatory cytokines and pro-fibrotic genes were also significantly downregulated by MES + HS. MES + HS decreased the expression level of cleaved caspase-3 and the number of TUNEL-positive cells, indicating that MES + HS exerted anti-apoptotic effect. Moreover, MES + HS activated the Akt signaling and induced the phosphorylation and inhibition of the apoptotic molecule BAD. In in vitro experiment, the Akt inhibitor abolished the MES + HS-induced Akt-BAD signaling and anti-apoptotic effect in ADR-treated cells. Collectively, our study suggested that MES + HS modulates ADR-induced pathologies and has renoprotective effect against ADR-induced NS via regulation of Akt-BAD axis.

Exploring protective effect of Glycine tabacina aqueous extract against nephrotic syndrome by network pharmacology and experimental verification

Background

Glycine tabacina (Labill.) Benth, one of the traditional Chinese herbal medicines, has been used for treatment of nephritis, osteoporosis, rheumatism, and menopausal syndrome. The aim of this study was to illuminate the therapeutic effect and mechanism of Glycine tabacina aqueous extract (GATE) in the treatment of nephrotic syndrome (NS).

Methods

UHPLC-DAD-MS/MS was used to analyze the chemical profile of GATE. Adriamycin (ADR)-induced NS mouse model and network pharmacology methods were conducted to explore the protective effect and mechanism of GATE on NS treatment.

Results

GATE administration significantly ameliorated symptoms of proteinuria and hyperlipidemia in NS mice, as evidenced by reduced excretion of urine protein and albumin, and decreased plasma levels of total cholesterol and triglyceride. Decreased blood urea nitrogen (BUN) and creatinine levels in NS mice suggested that GATE could prevent renal function decline caused by ADR. GATE treatment also inhibited ADR-induced pathological lesions of renal tissues as indicated by periodic acid Schiff staining. Six flavonoids of GATE were identified by using UHPLC-DAD-MS/MS. Network pharmacology analysis indicated that the protection of GATE in treating NS might be associated with the regulation of oxidative stress and inflammation. In addition, the in vivo experiment validated that treatment with GATE markedly decreased reactive oxygen species production, malonaldehyde level, and increased superoxide dismutase activity both in plasma and renal tissues. TNF-α level in plasma and protein expression in kidney were significantly decreased in GATE treatment groups.

Conclusions

Combination of network pharmacology analysis and experimental verification revealed that GATE exerts anti-NS effect possibly through modulating oxidative stress and inflammation, suggesting the potential application of GATE or its derivatives in the prevention and treatment of NS and other related kidney diseases.

Focal Segmental Glomerulosclerosis: State-of-the-Art and Clinical Perspective

Focal segmental glomerulosclerosis (FSGS) is a histological pattern of glomerular injury, rather than a single disease, that is caused by diverse clinicopathological entities with different mechanisms of injury with the podocyte as the principal target of lesion, leading to the characteristic sclerotic lesions in parts (i.e., focal) of some (i.e., segmental) glomeruli. The lesion of FSGS has shown an increasing prevalence over the past few decades and is considered the most common glomerular cause leading to ESKD. Primary FSGS, which usually presents with nephrotic syndrome, is thought to be caused by circulating permeability factors that have a main role in podocyte foot process effacement. Secondary forms of FSGS include maladaptive FSGS secondary to glomerular hyperfiltration such as in obesity or in cases of loss in nephron mass, virus-associated FSGS, and drug-associated FSGS that can result in direct podocyte injury. Genetic FSGS is increasingly been recognized and a careful evaluation of patients with atypical primary or secondary FSGS should be performed to exclude genetic causes. Unlike primary FSGS, secondary and genetic forms of FSGS do not respond to immunosuppression and tend not to recur after kidney transplantation. Distinguishing primary FSGS from secondary and genetic causes has a prognostic significance and is crucial for an appropriate management. In this review, we examine the pathogenesis, clinical approach to distinguish between the different causes, and current recommendations in the management of FSGS.