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.

Comparative outcomes of anticoagulation alone versus anticoagulation plus endovascular intervention in adults with isolated renal vein thrombosis

BACKGROUND

Limited therapeutic strategies are available for adults with isolated renal vein thrombosis (RVT). In the present study, we explore and compare the efficacy of anticoagulation therapy alone vs anticoagulation plus endovascular intervention in the treatment of this rare disease.

METHODS

In the present study, we analyzed the clinical data of RVT patients treated in a tertiary referral center in urban China from April 2012 to April 2022. These patients were classified into anticoagulation therapy (best medical treatment [BMT]) and endovascular intervention (endovascular-based treatment [EBT]) groups. The primary end points, including thrombus clearance and renal function changes, were evaluated by measuring the serum creatinine levels and glomerular filtration rates (GFRs).

RESULTS

A total of 40 consecutive patients with RVT (25 men and 15 women) were included in the present study, with a median age of 37 years (range, 18-72 years). Some patients developed symptoms, including 12 with low back pain (30%), 11 with lower extremity edema (28%), and 10 with abdominal pain (30%). Nephrotic syndrome was the underlying etiology for most patients (30 of 40; 75%). Additionally, 28 patients (70%) developed unilateral RVT, including 18 cases of left RVT (45%). Of the 40 patients, 17 had received BMT (42%) and 23 had received EBT (58%). In the acute phase of RVT, defined as <14 days from symptom onset, the EBT group had higher thrombus clearance and better improvement of creatinine and GFR after treatment compared with the BMT group (P < .05). In the subacute phase, defined as 14 to 30 days after symptom onset, thrombus clearance was higher in the EBT group than in the BMT group (P < .05). However, the improvement in creatinine and GFR were insignificantly different between the two groups (P > .05).

CONCLUSIONS

The etiologies of RVT can and should be investigated. In the present study, RVT was primarily caused by nephrotic syndrome in young patients and also was attributed to malignancy and lupus nephritis. In addition to anticoagulation therapy, endovascular intervention, including catheter-directed thrombolysis and mechanical thrombectomy, contributed to the improvement of renal function in patients with acute RVT. Endovascular intervention markedly promoted thrombus clearance in patients in the subacute phase but did not improve renal function. Therefore, endovascular intervention should be considered if RVT is diagnosed in the acute phase.

The pattern of steroid sensitivity and steroid resistance in childhood idiopathic nephrotic syndrome: A 5-year retrospective observational descriptive study in a South-East Nigerian tertiary hospital

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.

[Efficacy and safety of low-dose rituximab in treatment of pediatric nephrotic syndrome: a prospective randomized controlled trial]

OBJECTIVES

To study the efficacy and safety of repeated application of rituximab (RTX) at a low dose (200 mg/m2) versus the recommended dose (375 mg/m2) for remission maintenance in frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS).

METHODS

A randomized controlled trial was conducted for 29 children with FRNS/SDNS who received systemic treatment in the Department of Nephrology, Anhui Provincial Children's Hospital, from September 2020 to December 2021. These children were divided into a recommended dose group (n=14) and a low dose group (n=15) using a random number table. The two groups were compared in terms of general characteristics, changes in CD19 expression after RTX treatment, number of relapses, glucocorticoid dose, adverse reactions of RTX, and hospital costs.

RESULTS

After RTX treatment, both the low dose group and the recommended dose group achieved B-lymphocyte depletion and had significant reductions in the number of relapses and glucocorticoid dose (P<0.05). The low dose group had a comparable clinical effect to the recommended dose group after RTX treatment (P>0.05), and the low dose group had a significant reduction in hospital costs for the second, third, and fourth times of hospitalization (P<0.05). There were no serious adverse reactions in either group during RTX treatment and late follow-up, and there was no significant difference in adverse reactions between the two groups (P>0.05).

CONCLUSIONS

Repeated RTX treatment at a low dose has comparable clinical efficacy and safety to that at the recommended dose and can significantly reduce the number of FRNS/SDNS relapses and the amount of glucocorticoids used, with little adverse effect throughout the treatment cycle. Therefore, it holds promise for clinical application.

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.

Pulmonary hypertension, nephrotic syndrome, and polymyositis due to hepatitis C virus infection: A case report

BACKGROUND

Hepatitis C infection not only damages the liver but also often accompanies many extrahepatic manifestations. Incidences of pulmonary hypertension (PH) caused by hepatitis C are rare, and incidences of concurrent nephrotic syndrome and polymyositis are even rarer.

CASE SUMMARY

Herein we describe the case of a 57-year-old woman who was admitted to our department for intermittent chest tightness upon exertion for 5 years, aggravated with dyspnea for 10 d. After relevant examinations she was diagnosed with PH, nephrotic syndrome, and polymyositis due to chronic hepatitis C infection. A multi-disciplinary recommendation was that the patient should be treated with sildenafil and macitentan in combination and methylprednisolone. During treatment autoimmune symptoms, liver function, hepatitis C RNA levels, and cardiac parameters of right heart catheterization were monitored closely. The patient showed significant improvement in 6-min walking distance from 100 to 300 m at 3-mo follow-up and pulmonary artery pressure drops to 50 mmHg. Long-term follow-up is needed to confirm further efficacy and safety.

CONCLUSION

Increasing evidence supports a relationship between hepatitis C infection and diverse extrahepatic manifestations, but it is very rare to have PH, nephrotic syndrome, and polymyositis in a single patient. We conducted a literature review on the management of several specific extrahepatic manifestations of hepatitis C.

Focal Segmental Glomerulosclerosis Complicating Therapy With Inotersen, an Antisense Oligonucleotide Inhibitor: A Case Report

Inotersen is an antisense oligonucleotide inhibitor licensed for the treatment of polyneuropathy complicating hereditary transthyretin amyloidosis (ATTRv). Nephrotoxicity has been reported with inotersen, including progression to kidney failure. We describe what is to our knowledge the first reported case of inotersen-associated nephrotic syndrome secondary to focal segmental glomerulosclerosis (FSGS) and review the literature concerning inotersen-induced nephrotoxicity. We report a woman in her early 30s with ATTRv associated with the V50M transthyretin (TTR) variant, who presented with nephrotic syndrome 7 months after commencement of inotersen. Renal histology demonstrated FSGS and scanty glomerular amyloid deposition. Discontinuation of inotersen alone resulted in complete clinical and biochemical resolution of nephrotic syndrome. Inotersen is associated with significant nephrotoxicity. In the phase 3 NEURO-TTR clinical trial, 3% of patients in the treatment arm developed a crescentic glomerulonephritis. All affected patients carried the V50M TTR variant, which is known to be associated with renal amyloid deposition. This case adds to the spectrum of kidney disease associated with inotersen and indicates that discontinuation of the drug alone may result in resolution of renal complications without additional immunosuppression. Monitoring of kidney function is essential in patients with ATTRv receiving inotersen, particularly if there is evidence of existing renal amyloid.

The case for treatment of monogenic SRNS with calcineurin inhibitors

Currently, no evidence-based guidelines exist for treatment of children with monogenic steroid-resistant nephrotic syndrome. A retrospective study on 141 patients from Malakasioti et al. revealed that 27.6% responded to calcineurin inhibitor (CNI) treatment, and 75% of responders maintained stable kidney function. Virtually all CNI nonresponders developed progressive loss of kidney function. This study emphasized roles for CNIs in patients with monogenic steroid-resistant nephrotic syndrome, and the need for future studies to identify CNI response biomarkers.

A multicenter retrospective study of calcineurin inhibitors in nephrotic syndrome secondary to podocyte gene variants

While 44-83% of children with steroid-resistant nephrotic syndrome (SRNS) without a proven genetic cause respond to treatment with a calcineurin inhibitor (CNI), current guidelines recommend against the use of immunosuppression in monogenic SRNS. This is despite existing evidence suggesting that remission with CNI treatment is possible and can improve prognosis in some cases of monogenic SRNS. Herein, our retrospective study assessed response frequency, predictors of response and kidney function outcomes among children with monogenic SRNS treated with a CNI for at least three months. Data from 203 cases (age 0-18 years) were collected from 37 pediatric nephrology centers. Variant pathogenicity was reviewed by a geneticist, and 122 patients with a pathogenic and 19 with a possible pathogenic genotype were included in the analysis. After six months of treatment and at last visit, 27.6% and 22.5% of all patients respectively, demonstrated partial or full response. Achievement of at least partial response at six months of treatment conferred a significant reduction in kidney failure risk at last follow-up compared to no response (hazard ratio [95% confidence interval] 0.25, [0.10-0.62]). Moreover, risk of kidney failure was significantly lower when only those with a follow-up longer than two years were considered (hazard ratio 0.35, [0.14-0.91]). Higher serum albumin level at CNI initiation was the only factor related to increased likelihood of significant remission at six months (odds ratio [95% confidence interval] 1.16, [1.08-1.24]). Thus, our findings justify a treatment trial with a CNI also in children with monogenic SRNS.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A case of membranous nephropathy with microspherular deposits progressing to collapsing nephropathy and dialysis dependency, but with full recovery following immunosuppression

Membranous nephropathy with microspherular deposits is a rare renal condition associated with sub-nephrotic or nephrotic-range proteinuria. We report a case presenting with severe nephrotic syndrome and pathological features of collapsing glomerulopathy. This is the first case we are aware of that progressed to requiring dialysis. The patient received rituximab and corticosteroids. She has now been off dialysis for over a year with both serum creatinine and urine protein-creatinine ratio returning to baseline.

Successful Discontinuation of Glucocorticoid Treatment after Administration of a Calcineurin Inhibitor for Nephrotic Syndrome in a Patient with Lupus Nephritis

Systemic lupus erythematosus was diagnosed in a patient at 43 years old. When proteinuria recurred at 57 years old, the first kidney biopsy was performed, and class IV-G (A) +V lupus nephritis was diagnosed. The prednisolone dose was increased to 40 mg/day, and cyclosporine A was introduced. After 1 year, proteinuria had decreased to 0.1 g/day. Prednisolone was discontinued three years later, and cyclosporine A was continued. Thereafter, proteinuria did not reoccur. At 67 years old, a second kidney biopsy showed complete remission of lupus nephritis. Cyclosporine A enabled permanent discontinuation of glucocorticoids in a patient with lupus nephritis.

Pioglitazone enhances proteinuria reduction in complicated pediatric nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is a common pediatric kidney disease, yet current treatments for complicated NS are only partially effective and have significant toxicity. There is no Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved safe and effective treatment for NS. Thiazolidinediones (TZDs) have been shown to reduce proteinuria in both diabetic and non-diabetic kidney disease and in preclinical studies to directly protect podocytes from injury and reduce proteinuria. Here, we report on the potential utility of the addition of the TZD pioglitazone (PIO) to enhance proteinuria reduction in 8 children and young adults with steroid dependent NS and steroid resistant NS.

METHODS

Clinical data were analyzed in comparable time periods before and after the addition of PIO to their medical regimens. Eight NS patients with minimal change NS (n = 2), focal segmental glomerulosclerosis (FSGS) (n = 4), or collapsing FSGS (n = 2) were evaluated.

RESULTS

Prior to PIO initiation, all children and young adults had already received multiple immunosuppressive medications (mean = 3.75). Five of eight patients (63%; "Responders") had notable proteinuria reduction within 1 month of PIO initiation (62% reduction; P = 0.04) and normalization within 6 months (97% reduction; P = 0.04). PIO-related benefits among the responders included notable increases in serum albumin (2.5 to 3.7 g/dl; P = 0.08), dramatic reductions in hospitalizations for IV albumin infusions and diuresis (11 to 0; P < 0.01), and considerable reduction in total immunosuppression (43% reduction; P > 0.1). Importantly, no patients experienced any adverse events attributable to PIO during a total of 136 patient-months of treatment.

CONCLUSIONS

While confirmatory safety and efficacy studies are needed, these findings suggest pioglitazone (a non-immunosuppressive drug) may be useful to enhance proteinuria reduction in some children and young adults with complicated NS. 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.

Immunosuppressive Agent Options for Primary Nephrotic Syndrome: A Review of Network Meta-Analyses and Cost-Effectiveness Analysis

Therapeutic options with immunosuppressive agents for glomerular diseases have widened with refinements to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines from 2012 to 2021. However, international guidelines do not necessarily match the reality in each country. Expensive therapies such as rituximab and calcineurin inhibitors are sometimes inaccessible to patients with refractory nephrotic syndrome due to cost or regulations. Under the Japanese medical insurance system, rituximab is accessible but still limited to steroid-dependent patients who developed idiopathic nephrotic syndrome in childhood. Based on international KDIGO guidelines and other national guidelines, possible applications of immunosuppressive agents for nephrotic syndrome are comprehensively examined in this review. While rituximab has become the mainstay of immunosuppressive therapy for nephrotic syndrome, clinical trials have indicated that options such as cyclophosphamide, calcineurin inhibitors, and mycophenolate mofetil would be preferable. Given the rising number of patients with nephrotic syndrome worldwide, KDIGO guidelines mention the need for further consideration of cost-effectiveness. If the new option of rituximab is to be the first choice in combination with steroids for nephrotic syndrome, its cost-effectiveness should also be verified. Among the few studies examining the cost-effectiveness of treatments for nephrotic syndrome, administration of rituximab to young adults has been shown to be cost-beneficial, at least in Japan. However, further large-scale studies involving multiple facilities are needed to verify such findings. Network meta-analyses have concluded that the efficacy of rituximab remains controversial and confirmation through high-quality studies of large cohorts is needed. To this end, the mechanisms of action underlying immunosuppressive agents, both old and new, need to be understood and experience must be accumulated to evaluate possible effects and side effects.

Nephrotic Syndrome and Statin Therapy: An Outcome Analysis

Background and Objectives: Hypercholesterolemia in patients with nephrotic syndrome (NS) may predispose to cardiovascular events and alter kidney function. We aimed to evaluate statins efficiency in NS patients under immunosuppression using four endpoints: remission rate (RR), end-stage kidney disease (ESKD), major cardiovascular events (MACE), and thrombotic complications (VTE). Materials and Methods: We retrospectively examined the outcome at 24 months after diagnosis of 154 NS patients (age 53 (39–64) years, 64% male, estimated glomerular filtration rate (eGFR) 61.9 (45.2–81.0) mL/min). During the follow-up, the lipid profile was evaluated at 6 months and at 1 and 2 years. Results: The median cholesterol level was 319 mg/dL, and 83% of the patients received statins. Patients without statins (17%) had similar age, body mass index, comorbidities, blood lipids levels, NS severity, and kidney function. The most used statin was simvastatin (41%), followed by rosuvastatin (32%) and atorvastatin (27%). Overall, 79% of the patients reached a form of remission, 5% reached ESKD, 8% suffered MACE, and 11% had VTE. The mean time to VTE was longer in the statin group (22.6 (95%CI 21.7, 23.6) versus 20.0 (95%CI 16.5, 23.5) months, p 0.02). In multivariate analysis, statin therapy was not associated with better RR, kidney survival, or fewer MACE; however, the rate of VTE was lower in patients on statins (HR 2.83 (95%CI 1.02, 7.84)). Conclusions: Statins did not improve the remission rate and did not reduce the risk of MACE or ESKD in non-diabetic nephrotic patients. However, statins seemed to reduce the risk of VTE. Further randomized controlled studies are needed to establish statins’ role in NS management.

Genetic Studies in Infants with Congenital Nephrotic Syndrome: A Case Series

Information on the genetic profile of congenital nephrotic syndrome (CNS) from India is scarce. The management of CNS is largely supportive of the setting of developing countries, mainly via the administration of intravenous albumin infusions, angiotensin-converting enzyme inhibitors, and levothyroxine. Inadequate infrastructure and management facilities, including genetic analyses, further hamper the outcome. These infants may progress to end-stage renal disease, and mortality is high in infancy. Here, we report a case series of four infants (aged 14-60 days) with CNS from our center with genetic mutations (including mutations in the NPHS1 and LAMB2 genes) that were not described in previous reports from India. Although responsiveness to enalapril has been documented in anecdotal reports of NPHS1 mutations, our case series of four infants did not exhibit any response to enalapril. Our case series adds to the existing literature regarding the genetic profile of CNS in India.

Primary membranous nephropathy: an endless story

Primary membranous nephropathy (PMN) is an autoimmune disease caused by the attack of autoantibodies against podocyte antigens leading to the in situ production of immune complexes. However, the etiology is unknown and the pathogenesis is still far from being completely elucidated. MN is prevalently idiopathic or primary, but in about 20-30% of cases it is secondary to chronic infections, systemic diseases, exposure to drugs, or malignancy. The differentiation between primary and secondary MN may be difficult, particularly when MN precedes signs and symptoms of the original disease, as in some cases of cancer or systemic lupus erythematosus. The natural course of PMN is variable, but in the long term 40-60% of patients with nephrotic syndrome progress to end-stage renal disease (ESRD) or die from thrombotic or cardiovascular events. PMN is a treatable disease. Patients with asymptomatic proteinuria should receive supportive care. Immunosuppressive treatments should be given to patients with nephrotic syndrome or risk of progression. The most frequently adopted treatments rely on cyclical therapy alternating steroids with a cytotoxic agent every other month, i.e., rituximab at different doses, or calcineurin inhibitors plus low-dose steroids. A good rate of response may be obtained but relapses can occur. Randomized controlled trials, with adequate size, long-term follow-up, and fair definition of endpoints are needed to identify treatment with the best therapeutic index.

[Distribution of memory B cell subsets in peripheral blood of children with frequently relapsing nephrotic syndrome]

OBJECTIVES

To investigate the change in the distribution of memory B cell subsets in children with frequently relapsing nephrotic syndrome (FRNS) during the course of the disease.

METHODS

A total of 35 children with primary nephrotic syndrome (PNS) who attended the Department of Pediatrics of the Affiliated Hospital of Xuzhou Medical University from October 2020 to October 2021 were enrolled as subjects in this prospective study. According to the response to glucocorticoid (GC) therapy and frequency of recurrence, the children were divided into two groups: FRNS (n=20) and non-FRNS (NFRNS; n=15). Fifteen children who underwent physical examination were enrolled as the control group. The change in memory B cells after GC therapy was compared between groups, and its correlation with clinical indicators was analyzed.

RESULTS

Before treatment, the FRNS and NFRNS groups had significantly increased percentages of total B cells, total memory B cells, IgD+ memory B cells, and IgE+ memory B cells compared with the control group, and the FRNS group had significantly greater increases than the NFRNS group (P<0.05); the FRNS group had a significantly lower percentage of class-switched memory B cells than the NFRNS and control groups (P<0.05). After treatment, the FRNS and NFRNS groups had significant reductions in the percentages of total B cells, total memory B cells, IgM+IgD+ memory B cells, IgM+ memory B cells, IgE+ memory B cells, IgD+ memory B cells, and IgG+ memory B cells (P<0.05) and a significant increase in the percentage of class-switched memory B cells (P<0.05). The FRNS group had a significantly higher urinary protein quantification than the NFRNS and control groups (P<0.05) and a significantly lower level of albumin than the control group (P<0.05). In the FRNS group, urinary protein quantification was negatively correlated with the percentage of class-switched memory B cells and was positively correlated with the percentage of IgE+ memory B cells (P<0.05).

CONCLUSIONS

Abnormal distribution of memory B cell subsets may be observed in children with FRNS, and the percentages of IgE+ memory B cells and class-switched memory B cells can be used as positive and negative correlation factors for predicting recurrence after GC therapy in these children.

EditorialAssignment

INTRODUCTION

Primary membranous nephropathy (PMN) is a major cause of nephrotic syndrome in adults. Rituximab has been recommended in the treatment of PMN by the updated Kidney Disease Improved Outcome guideline. However, the optimal dosing regimen of rituximab for the initial treatment of patients with PMN is unclear.

METHODS AND ANALYSIS

A comprehensive screening will be performed by searching PubMed, Embase and the CENTRAL (Cochrane Central Register of Controlled Trials) without language restriction. Studies evaluating the efficacy of rituximab monotherapy using the following types of dosing regimens will be included: high-dose regimen; standard regimen and low-dose regimen. Studies with less than 10 participants will be excluded. The primary outcome is the remission rate at 12 months. The secondary outcomes are remission rate at 6 and 24 months, complete remission rate at 6, 12 and 24 months, relapse at 6, 12 and 24 months, and side effects. Risk of Bias In Non-randomised Studies of Interventions tool will be used to assess the risk of bias for non-randomised studies and the Cochrane risk of bias assessment tool will be used for randomised controlled trials. The pooled remission rate, complete remission rate, relapse rate and side effects will be estimated using the metaprop command. All analyses will be calculated using Stata software (V.15.0; StataCorp).

ETHICS AND DISSEMINATION

Ethics approval is not required. The results of our study will be submitted to a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42022319401.