T regulatory cell function in idiopathic minimal lesion nephrotic syndrome

Characterizing Glomerular Barrier Dysfunction with Patient-Derived Serum in Glomerulus-on-a-Chip Models: Unveiling New Insights into Glomerulonephritis

Glomerulonephritis (GN) is characterized by podocyte injury or glomerular filtration dysfunction, which results in proteinuria and eventual loss of kidney function. Progress in studying the mechanism of GN, and developing an effective therapy, has been limited by the absence of suitable in vitro models that can closely recapitulate human physiological responses. We developed a microfluidic glomerulus-on-a-chip device that can recapitulate the physiological environment to construct a functional filtration barrier, with which we investigated biological changes in podocytes and dynamic alterations in the permeability of the glomerular filtration barrier (GFB) on a chip. We also evaluated the potential of GN-mimicking devices as a model for predicting responses to human GN. Glomerular endothelial cells and podocytes successfully formed intact monolayers on opposite sides of the membrane in our chip device. Permselectivity analysis confirmed that the chip was constituted by a functional GFB that could accurately perform differential clearance of albumin and dextran. Reduction in cell viability resulting from damage was observed in all serum-induced GN models. The expression of podocyte-specific marker WT1 was also decreased. Albumin permeability was increased in most models of serum-induced IgA nephropathy (IgAN) and membranous nephropathy (MN). However, sera from patients with minimal change disease (MCD) or lupus nephritis (LN) did not induce a loss of permeability. This glomerulus-on-a-chip system may provide a platform of glomerular cell culture for in vitro GFB in formation of a functional three-dimensional glomerular structure. Establishing a disease model of GN on a chip could accelerate our understanding of pathophysiological mechanisms of glomerulopathy.

Current understanding of the molecular mechanisms of circulating permeability factor in focal segmental glomerulosclerosis

The pathogenetic mechanisms underlying the onset and the post-transplant recurrence of primary focal segmental glomerulosclerosis (FSGS) are complex and remain yet to be fully elucidated. However, a growing body of evidence emphasizes the pivotal role of the immune system in both initiating and perpetuating the disease. Extensive investigations, encompassing both experimental models and patient studies, have implicated T cells, B cells, and complement as crucial actors in the pathogenesis of primary FSGS, with various molecules being proposed as potential "circulating factors" contributing to the disease and its recurrence post kidney-transplantation. In this review, we critically assessed the existing literature to identify essential pathways for a comprehensive characterization of the pathogenesis of FSGS. Recent discoveries have shed further light on the intricate interplay between these mechanisms. We present an overview of the current understanding of the engagement of distinct molecules and immune cells in FSGS pathogenesis while highlighting critical knowledge gaps that require attention. A thorough characterization of these intricate immune mechanisms holds the potential to identify noninvasive biomarkers that can accurately identify patients at high risk of post-transplant recurrence. Such knowledge can pave the way for the development of targeted and personalized therapeutic approaches in the management of FSGS.

New-onset minimal change disease following the Moderna COVID-19 vaccine

We report the case of nephrotic syndrome after COVID-19 vaccination. The patient was a man in his 30s with no comorbidities other than atopic dermatitis. Over the course of 2 weeks after the first COVID-19 vaccination, systemic oedema gradually appeared. He was referred to the nephrology department for investigation of the systemic oedema. On admission, he presented with pitting oedema in his lower extremities. Initial examinations revealed massive urinary protein and decreased serum albumin, at 13.9 g/g Cr and 1.5 g/dL, respectively. Renal biopsy was performed, and minimal change disease was diagnosed. Prednisolone 60 mg/day was promptly started on the 5th day of hospitalisation, and complete remission was achieved on the 12th day. Prednisolone was once tapered off in 1.5 years successfully though minimal change disease was relapsed in 1 month after the steroid withdrawal.

The kinetics of mTORC1 activation associates with FOXP3 expression pattern of CD4+ T cells and outcome of steroid-sensitive minimal change disease

Minimal change disease (MCD) usually responds to glucocorticoids (GCs) but relapses in most cases. Relapse pathogenesis after complete remission (CR) remains unclear. We hypothesized that FOXP3+ T regulatory cell (Treg) dysregulation may drive early relapses (ER). In this study, a cohort of 23 MCD patients were treated with a conventional GC regimen for the initial onset of nephrotic syndrome. Upon GC withdrawal, seven patients suffered from ER, while 16 patients sustained remission (SR) during the 12-month follow-up. Patients with ER had reduced FOXP3+ Treg proportions compared with healthy controls. Treg reduction, accompanied by IL-10 impairment, was ascribed to a proportional decline of FOXP3medium rather than FOXP3high cells. GC-induced CR was marked by a rise in the proportions of FOXP3+ and FOXP3medium cells compared to baseline levels. These increases declined in patients with ER. The expression level of phosphorylated ribosomal protein S6 was used to track the dynamic shifts in mTORC1 activity within CD4+ T cells of MCD patients at various stages of treatment. Baseline mTORC1 activity was inversely correlated with FOXP3+ and FOXP3medium Treg proportion. The mTORC1 activity in CD4+ T cells served as a reliable indicator for ER and demonstrated improved performance when paired with FOXP3 expression. Mechanically, targeting mTORC1 intervention by siRNAs sufficiently altered the conversion pattern of CD4+ T cell to FOXP3+ Treg. Taken together, the activity of mTORC1 in CD4+ T cells can act as a credible predictor for ER in MCD, especially when combined with FOXP3 expression, and may offer a potential therapeutic avenue for the treatment of podocytopathies.

Proteomics of Plasma and Plasma-Treated Podocytes: Application to Focal and Segmental Glomerulosclerosis

Focal and segmental glomerulosclerosis (FSGS) is a severe form of idiopathic nephrotic syndrome (INS), a glomerulopathy of presumably immune origin that is attributed to extrarenal pathogenic circulating factors. The recurrence of FSGS (rFSGS) after transplant occurs in 30% to 50% of cases. The direct analysis of patient plasma proteome has scarcely been addressed to date, mainly due to the methodological difficulties associated with plasma complexity and dynamic range. In this study, first, we compared different methods of plasma preparation, second, we compared the plasma proteomes of rFSGS and controls using two preparation methods, and third, we analyzed the early proximal signaling events in podocytes subjected to patient plasma, through a combination of phosphoproteomics and lipid-raft proteomics (raftomics). By combining immunodepletion and high pH fractionation, we performed a differential proteomic analysis of soluble plasma proteins and of extracellular vesicles (EV) obtained from healthy controls, non-INS patient controls, and rFSGS patients (n = 4). In both the soluble- and the EV-protein sets from the rFSGS patients, we found a statistically significant increase in a cluster of proteins involved in neutrophil degranulation. A group of lipid-binding proteins, generally associated with lipoproteins, was found to be decreased in the soluble set from the rFSGS patients. In addition, three amino acid transporters involved in mTORC1 activation were found to be significantly increased in the EV from the rFSGS. Next, we incubated human podocytes for 30 min with 10% plasma from both groups of patients. The phosphoproteomics and raftomics of the podocytes revealed profound differences in the proteins involved in the mTOR pathway, in autophagy, and in cytoskeleton organization. We analyzed the correlation between the abundance of plasma and plasma-regulated podocyte proteins. The observed changes highlight some of the mechanisms involved in FSGS recurrence and could be used as specific early markers of circulating-factor activity in podocytes.

Preliminary study of anti-CD40 and ubiquitin proteasome antibodies in primary podocytopaties

Background

Minimal change disease and focal segmental glomerulosclerosis are primary podocytopathies that are clinically presented in adults presenting with severe nephrotic syndrome. The pathogenesis of these diseases is not clear and many questions remain to be answered. A new concept about the role of changes in the antigenic determinant of podocytes and the production of anti-podocyte antibodies that cause podocyte damage is being developed. The aim of the study is to evaluate the levels of anti-CD40 and anti-ubiquitin carboxyl-terminal hydrolase L1 (anti-UCH-L1) antibodies in patients with podocytopathies in comparison with other glomerulopathies.

Methods

One hundred and six patients with glomerulopathy and 11 healthy subjects took part in the study. A histological study revealed primary FSGS in 35 patients (genetic cases of FSGS and secondary FSGS in the absence of NS were excluded), 15 had MCD, 21 - MN, 13 - MPGN, 22 patients - IgA nephropathy. The effect of steroid therapy was evaluated in patients with podocytopathies (FSGS and MCD). The serum levels of anti-UCH-L1 and anti-CD40 antibodies were measured by ELISA before steroid treatment.

Results

The levels of anti-UCH-L1 antibodies were significantly higher in MCD patients and anti-CD40 antibodies were higher in MCD and FSGS than in the control group and other groups of glomerulopathies. In addition, the level of anti-UCH-L1 antibodies was higher in patients with steroid-sensitive FSGS and MCD, and anti-CD40 antibodies were lower than in patients with steroid-resistant FSGS. An increase in anti-UCH-L1 antibody levels above 6.44 ng/mL may be a prognostic factor of steroid-sensitivity. The ROC curve (AUC = 0.875 [95% CI 0.718-0.999]) for response to therapy showed a sensitivity of 75% and specificity of 87.5%.

Conclusion

An increase in the level of anti-UCH-L1 antibodies is specific for steroid-sensitive FSGS and MCD, while an increase in anti-CD40 antibodies - for steroid-resistant FSGS, compared with other glomerulopathies. It suggests that these antibodies could be a potential factor for differential diagnosis and treatment prognosis.

Immunophenotypic Alterations in Adult Patients with Steroid-Dependent and Frequently Relapsing Nephrotic Syndrome

Immune dysregulation plays a key role in the pathogenesis of steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS). However, in contrast with evidence from the pediatric series, no major B- or T-cell alterations have been described for adults. In these patients, treatment with rituximab allows safe discontinuation of steroids, but long-term efficacy is variable, and some patients experience NS relapses after B cell reconstitution. In this study, we aimed to determine disease-associated changes in the B and T cell phenotype of adult patients with SDND/FRNS after steroid-induced remission. We also investigated whether any of these changes in immune cell subsets could discriminate between patients who developed NS relapses after steroid-sparing treatment with rituximab from those who did not. Lymphocyte subsets in SDNS/FRNS patients (n = 18) were compared to those from patients with steroid-resistant NS (SRNS, n = 7) and healthy volunteers (HV, n = 15). Before rituximab, SDND/FRNS patients showed increased frequencies of total and memory B cells, mainly with a CD38-negative phenotype. Within the T-cell compartment, significantly lower levels of FOXP3⁺ regulatory T cells (Tregs) were found, mostly due to a reduction in CD45RO⁺ memory Tregs compared to both SRNS and HV. The levels of CD45RO⁺ Tregs were significantly lower at baseline in patients who relapsed after rituximab (n = 9) compared to patients who did not (n = 9). In conclusion, patients with SDND/FRNS displayed expansion of memory B cells and reduced memory Tregs. Treg levels at baseline may help identify patients who will achieve sustained remission following rituximab infusion from those who will experience NS relapses.

Effects of the mTOR Pathway on the Balance of Th2/Treg Cells in Children with Idiopathic Nephrotic Syndrome

Introduction

Immune dysfunction contributes to the progression of idiopathic nephrotic syndrome (INS), but the details of the pathogenesis of progression remain unknown. This study of children with INS investigated the relationship of activation of the mechanistic target of rapamycin (mTOR) pathway (PI3K/AKT/mTOR/p70S6K) with the levels of T helper 2/regulatory T (Th2/Treg) cells.

Materials and Methods

Twenty children with active INS (before steroid treatment), 20 children with remitting INS (INS-R, after steroid treatment), and 20 healthy control children (Ctrl) were enrolled. The levels of Th2/Treg cells in their peripheral circulatory systems were measured using flow cytometry, and the concentration of interleukin (IL)-4 was determined using a cytometric bead array (CBA). The levels of PI3K, AKT, mTOR, p70S6K, and transcription factors associated with Th2/Treg cells were measured using real-time polymerase chain reaction.

Results

The INS group had a greater proportion of circulating Th2 cells; level of IL-4 protein; and levels of GATA, PI3K, AKT, mTOR, and p70S6K mRNAs than the Ctrl group (all P < 0.05), but a lower proportion of circulating Tregs and expression of Foxp3 (both P < 0.05). Patients in the INS-R group had normalization of these markers (all P < 0.05). Patients in the INS group had negative correlation in the percentage of Treg cells with Th2 cells and with IL-4 level and a negative correlation in the levels of GATA3 and Foxp3 mRNAs.

Conclusions

Patients with active INS had an imbalance of Th2/Treg cells, which might result from the aberrant signaling of the mTOR pathway (PI3K/AKT/mTOR/p70S6K).

Epigenetic Mechanisms and Nephrotic Syndrome: A Systematic Review

A small subset of people with nephrotic syndrome (NS) have genetically driven disease. However, the disease mechanisms for the remaining majority are unknown. Epigenetic marks are reversible but stable regulators of gene expression with utility as biomarkers and therapeutic targets. We aimed to identify and assess all published human studies of epigenetic mechanisms in NS. PubMed (MEDLINE) and Embase were searched for original research articles examining any epigenetic mechanism in samples collected from people with steroid resistant NS, steroid sensitive NS, focal segmental glomerulosclerosis or minimal change disease. Study quality was assessed by using the Joanna Briggs Institute critical appraisal tools. Forty-nine studies met our inclusion criteria. The majority of these examined micro-RNAs (n = 35, 71%). Study quality was low, with only 23 deemed higher quality, and most of these included fewer than 100 patients and failed to validate findings in a second cohort. However, there were some promising concordant results between the studies; higher levels of serum miR-191 and miR-30c, and urinary miR-23b-3p and miR-30a-5p were observed in NS compared to controls. We have identified that the epigenome, particularly DNA methylation and histone modifications, has been understudied in NS. Large clinical studies, which utilise the latest high-throughput technologies and analytical pipelines, should focus on addressing this critical gap in the literature.

Review of the Role of Rituximab in the Management of Adult Minimal Change Disease and Immune-Mediated Focal and Segmental Glomerulosclerosis

Background

Minimal change disease and primary FSGS are podocytopathies but are also immune-mediated diseases. Rituximab acts via multiple mechanisms by tilting the balance between autoreactive B and T cells in favor of regulatory B and T cells. The consequences are decreased production of cytokines, chemokines, and permeability factors by these cells. In the past decade, we have seen the discovery of autoantibodies mediating nephrotic syndrome (anti-annexin A2 antibody, anti-UCHL1 antibody, and anti-nephrin antibody), and rituximab decreases their production. Rituximab also binds to podocyte SMPDL3b and has direct podocyte actions.

Summary

Rituximab's role in managing these primary podocytopathies has been discussed in this brief review. Rituximab has been used extensively in children and adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, rituximab is not very promising in adult steroid-resistant nephrotic syndrome. Although ofatumumab would cause prolonged B-cell depletion and is fully humanized, it is unclear if it is superior to rituximab in preventing relapse of nephrotic syndrome.

Key Messages

Rituximab therapy can induce prolonged remission in adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, no good data exist on using rituximab in steroid-resistant nephrotic syndrome.

Change of circulating lymphocyte subsets is related to disease activity and secondary infection in children with primary nephrotic syndrome-a retrospective study

BACKGROUND

Primary nephrotic syndrome (PNS) is an immune-mediated glomerular disease that often reoccurs. However, the characteristics of circulating lymphocyte subsets in PNS children remain unclear. Immunosuppressive therapy can lead to temporary or persistent remissions, but also increases the risk of infection, and whether the circulating lymphocyte subsets can be used to predict the secondary infection also remains unclear. Here, we explored the distribution of lymphocyte subpopulations in the different stages of PNS, and its predictive value of secondary infection in pediatric patients.

METHODS

We included 89 children who were first PNS episodes or diagnosed with PNS admitted to Nanfang Hospital from September 2019 to April 2021, and 19 healthy children were recruited as controls (C). PNS patients were divided into three groups according to their serum biochemical tests: active group (A), partial remission (PR) group, and complete remission (CR) group. PNS patients with infection symptoms were divided into a co-infection group, others were divided into the non-infection group. The peripheral lymphocyte subsets were analyzed by flow cytometry. The relationship between the peripheral lymphocyte subsets and PNS activity or infection was analyzed.

RESULTS

Compared to the healthy controls, the PNS patients' CD8⁺CD28⁺ T cell (T_C) (C: 16.6%, 450.8/µL; 
A: 29.1%, P=0.000, 886.1/µL, P=0.012; PR: 25.7%, P=0.000, 817.3/µL, P=0.012; CR: 24.9%, P=0.001, 747.9/µL, P=0.020), and CD4⁺CD45RO⁺ ("memory" helper) T cells (C: 13.2%, 358.9/µL; A: 15.7%, P=0.036, 578.7/µL, P=0.001; PR: 17.6%, P=0.002, 610.0/µL, P=0.000; CR: 13.7%, P=0.676, 398.1/µL, P=0.525) were elevated. In addition, the regulatory T cells counts (non-infection: 117.9/µL; Co-infection: 73.3/µL, P=0.001) were significantly lower in patients with infection. We found that the predictive value measured by the area under the curve (AUC) showed that the AUC (t) T_reg cell counts (61.5-84.5%) were almost always higher than the AUC for the (t) CD4⁺ T cell counts (55.1-77.1%).

CONCLUSIONS

In this study, we found that T cell subpopulations had different characteristics in PNS during different disease phases. The CD8⁺CD28⁺ T cells, and CD4⁺CD45RO⁺ T cells increased at the disease quiescence of PNS. Moreover, CD4⁺ T cell subsets (regulatory T cell <82.5/µL) had higher predictive value than CD4⁺ T cell counts for PNS infection.

Alternatively Spliced Landscape of PPARγ mRNA in Podocytes Is Distinct from Adipose Tissue

Podocytes are highly differentiated epithelial cells, and their structural and functional integrity is compromised in a majority of glomerular and renal diseases, leading to proteinuria, chronic kidney disease, and kidney failure. Traditional agonists (e.g., pioglitazone) and selective modulators (e.g., GQ-16) of peroxisome-proliferator-activated-receptor-γ (PPARγ) reduce proteinuria in animal models of glomerular disease and protect podocytes from injury via PPARγ activation. This indicates a pivotal role for PPARγ in maintaining glomerular function through preservation of podocytes distinct from its well-understood role in driving insulin sensitivity and adipogenesis. While its transcriptional role in activating adipokines and adipogenic genes is well-established in adipose tissue, liver and muscle, understanding of podocyte PPARγ signaling remains limited. We performed a comprehensive analysis of PPARγ mRNA variants due to alternative splicing, in human podocytes and compared with adipose tissue. We found that podocytes express the ubiquitous PPARγ Var 1 (encoding γ1) and not Var2 (encoding γ2), which is mostly restricted to adipose tissue and liver. Additionally, we detected expression at very low level of Var4, and barely detectable levels of other variants, Var3, Var11, VartORF4 and Var9, in podocytes. Furthermore, a distinct podocyte vs. adipocyte PPAR-promoter-response-element containing gene expression, enrichment and pathway signature was observed, suggesting differential regulation by podocyte specific PPARγ1 variant, distinct from the adipocyte-specific γ2 variant. In summary, podocytes and glomeruli express several PPARγ variants, including Var1 (γ1) and excluding adipocyte-specific Var2 (γ2), which may have implications in podocyte specific signaling and pathophysiology. This suggests that that new selective PPARγ modulators can be potentially developed that will be able to distinguish between the two forms, γ1 and γ2, thus forming a basis of novel targeted therapeutic avenues.

Selective modulator of nuclear receptor PPARγ with reduced adipogenic potential ameliorates experimental nephrotic syndrome

Glomerular disease manifests as nephrotic syndrome (NS) with high proteinuria and comorbidities, and is frequently refractory to standard treatments. We hypothesized that a selective modulator of PPARγ, GQ-16, will provide therapeutic advantage over traditional PPARγ agonists for NS treatment. We demonstrate in a pre-clinical NS model that proteinuria is reduced with pioglitazone to 64%, and robustly with GQ-16 to 81% of nephrosis, comparable to controls. Although both GQ-16 and pioglitazone restore glomerular-Nphs1, hepatic-Pcsk9 and serum-cholesterol, only GQ-16 restores glomerular-Nrf2, and reduces hypoalbuminemia and hypercoagulopathy. GQ-16 and pioglitazone restore common and distinct glomerular gene expression analyzed by RNA-seq and induce insulin sensitizing adipokines to various degrees. Pioglitazone but not GQ-16 induces more lipid accumulation and aP2 in adipocytes and white adipose tissue. We conclude that selective modulation of PPARγ by a partial agonist, GQ-16, is more advantageous than pioglitazone in reducing proteinuria, NS associated comorbidities, and adipogenic side effects of full PPARγ agonists.

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.

Trends in pediatric nephrotic syndrome

Nephrotic syndrome (NS) is relatively common in children, with most of its histological types being minimal changed disease. Its etiology has long been attributed to lymphocyte (especially T-cell) dysfunction, while T-cell-mediated vascular hyperpermeability increases protein permeability in glomerular capillaries, leading to proteinuria and hypoproteinemia. Based on this etiology, steroids and immunosuppressive drugs that are effective against this disease have also been considered to correct T-cell dysfunction. However, in recent years, this has been questioned. The primary cause of NS has been considered damage to glomerular epithelial cells and podocyte-related proteins. Therefore, we first describe the changes in expression of molecules involved in NS etiology, and then describe the mechanism by which abnormal expression of these molecules induces proteinuria. Finally, we consider the mechanism by which infection causes the recurrence of NS.

Low regulatory T-cells: A distinct immunological subgroup in minimal change nephrotic syndrome with early relapse following rituximab therapy

Rituximab is an important second line therapy in difficult nephrotic syndrome (NS), especially given toxicity of long-term glucocorticoid or calcineurin inhibitor (CNI) use. However, clinical response to rituximab is heterogenous. We hypothesized that this was underpinned by immunological differences amongst patients with NS. We recruited a cohort of 18 subjects with glucocorticoid-dependent or glucocorticoid-resistant childhood-onset minimal change NS who received rituximab either due to CNI nephrotoxicity, or due to persistent glucocorticoid toxicity with inadequate response to cyclophosphamide or CNIs. Immunological subsets, T-cell activation assays and plasma cytokines were measured at baseline and 6-months post-rituximab. Time to relapse was bifurcated: 56% relapsed within one year ("early relapse"), while the other 44% entered remission mainly lasting ≥3 years ("sustained remission"). At baseline, early relapse compared to sustained remission group had lower regulatory T-cells (Tregs) [2.94 (2.25, 3.33)% vs 6.48 (5.08, 7.24)%, P<0.001], PMA-stimulated IL-2 [0.03 (0, 1.85)% vs 4.78 (0.90, 9.18)%, P=0.014] and IFNγ [2.22 (0.18, 6.89)% vs 9.47 (2.72, 17.0)%, P=0.035] levels. Lower baseline Treg strongly predicted early relapse (ROC-AUC 0.99, 95% CI 0.97-1.00, P<0.001). There were no differences in baseline plasma cytokine levels. Following rituximab, there was significant downregulation of Th2 cytokines in sustained remission group (P=0.038). In particular, IL-13 showed a significant decrease in sustained remission group [-0.56 (-0.64, -0.35)pg/ml, P=0.007)], but not in the early relapse group. In conclusion, early relapse following rituximab is associated with baseline reductions in Treg and T-cell hyporesponsiveness, which suggest chronic T-cell activation and may be useful predictive biomarkers. Sustained remission, on the other hand, is associated with downregulation of Th2 cytokines following rituximab.

The long and winding road to the etiology of idiopathic nephrotic syndrome in children: Focusing on abnormalities in the gut microbiota

Childhood nephrotic syndrome is idiopathic in 90% of cases. Despite its relatively high prevalence (30-35 per 100 000 individuals under 15 years old), the etiology of the disease remains elusive. It has become clear that oxidants are elevated, and antioxidants are decreased, at onset of idiopathic nephrotic syndrome (INS). It was suggested that overexpression of podocyte CD80 induced by abnormalities of Tregs was involved in the pathogenesis of INS. Subsequently, it became clear that quantitative or qualitative reduction of Tregs has a profound impact on the development of INS. To address why Tregs are decreased at onset of INS, it was hypothesized that a decrease in Tregs may be associated with dysbiosis. Given the critical role of butyrate-producing bacteria in the differentiation of Tregs, the gut microbiota was analyzed with a particular focus on the abundance of butyrate-producing bacteria, and it was found that pediatric patients with INS had low levels of butyrate in their stool and a low percentage of butyrate-producing bacteria. Interestingly, it was recently reported that gut dysbiosis increases oxidative stress in the intestinal tract. Taken together, we currently hypothesize that gut dysbiosis is associated with a predisposition to INS because of immunological abnormalities characterized by abnormal Tregs with increased oxidative stress.

Steroid Minimization in Adults with Minimal Change Disease

Background

Minimal change disease (MCD) causes approximately 10% of nephrotic syndrome in adults. While glucocorticoids (GCs) effectively induce remission in MCD, the disease has a high relapse rate (50-75%), and repeated exposure to GCs is often required. The adverse effects of GCs are well recognized and commonly encountered with the high doses and recurrent courses used in MCD.

Summary

In this review, we will discuss the standard therapy of MCD in adults and then describe new therapeutic options in induction therapy and treatment of relapses in MCD, minimizing the exposure to GCs.

Key Messages

Steroid minimization strategies may decrease adverse effects in the treatment of MCD.

Efficacy and safety of Huaiqihuang granule as adjuvant treatment for primary nephrotic syndrome in children: a meta-analysis and systematic review

BACKGROUND

Huaiqihuang (HQH) granule is a traditional Chinese herbal complex that has been used as an adjuvant treatment in clinics for the primary nephrotic syndrome (PNS) for many years. However, the effectiveness and safety of HQH have not been systematically discussed. This review aimed to evaluate the effectiveness and safety of HQH in paediatric patients with PNS.

METHODS

The following databases were searched from inception to Mar 2019: MEDLINE, Cochrane Library, EMBASE, CNKI, Wanfang Database, the Chinese Scientific Journal Database and the Chinese biomedical literature service system. All the randomized controlled trials (RCTs) eligible for inclusion were included. The primary outcomes were relapse, infection, remission and adverse events. The secondary outcomes included serum immunoglobulin levels (IgA, IgG or IgM), T-lymphocyte subtype (CD3+ , CD4+ , CD8+ , CD4+ /CD8+), IL-10, TNF-α, TNF-γ, total cholesterol and time of proteinuria turning negative.

RESULTS

Fourteen RCTs (885 patients) were identified. Treatment with HQH reduced the chance of relapse [relative risk (RR): 0.47; 95% CI: 0.34, 0.66; P < 0.001] and infections (RR: 0.47; 95% CI: 0.35, 0.62; P < 0.001). No significant difference was found in adverse events. HQH also increased the serum levels of IgA [weighted mean difference (WMD): 0.40; 95% CI: 0.20, 0.60; P < 0.001] and IgG (WMD: 1.58; 95% CI: 1.38-1.78; P < 0.001), as well as CD4+ [standard mean difference (SMD): 0.90; 95% CI: 0.12-1.68; P = 0.02], CD3+ (WMD: 4.04; 95% CI: 3.27-4.82; P < 0.001), and the CD4+/CD8+ratio (WMD: 0.31; 95% CI: 0.21-0.41; P < 0.001), but decreased the level of CD8+ cells (WMD: -3.39; 95% CI: -5.73-1.05; P = 0.004). No statistically significant difference was found in IgM (WMD: 0.05; 95% CI: -0.13, 0.24; P = 0.57).

CONCLUSIONS

HQH could reduce the rate of relapse and the frequency of infection in children with PNS. No apparent adverse effects were found. Moreover, the beneficial influence of HQH may act through immunomodulation. Additional multi-center, large-sample, high-quality studies are needed to confirm the effectiveness and safety of HQH.

Idiopathic nephrotic syndrome in children: role of regulatory T cells and gut microbiota

BACKGROUND

We investigated whether an association exists between regulatory T cells (Tregs) during initial presentation in children with idiopathic nephrotic syndrome (INS) and later development of frequently relapsing INS.

METHODS

Blood samples were obtained at onset and at remission from 25 patients (median age, 4.0 years) with INS; eight did not show relapse after initial response (non-relapsing [NR]), whereas 17 showed frequent relapses (frequently relapsing [FR]). Tregs were measured by flow cytometry; increases were compared between groups. Fecal samples were obtained at onset from 20 patients with INS, as well as from 20 age-matched healthy children. Gut microbiota composition was assessed using 16S ribosomal RNA (rRNA) sequencing (ion PGM).

RESULTS

The rate of increase in Tregs from onset to remission was significantly lower in the FR group (124.78%) than in the NR group (879.16%; P < 0.001). Additionally, 16S rRNA sequencing of gut microbiota showed that the proportion of butyric acid-producing bacteria was significantly lower in the FR group (7.08%) than in the healthy children (17.45%; P < 0.001).

CONCLUSIONS

In children with INS, small increases in Tregs in response to steroid treatment were associated with subsequent increased risk of frequent relapses. In addition, the FR group had a greater degree of dysbiosis at onset.

IMPACT

A low rate of Tregs increase is associated with subsequent frequent relapses of INS. The increase in Tregs in response to steroid treatment was small when dysbiosis was present in patients with INS, particularly when the proportion of butyrate-producing bacteria was considerably reduced We presume that improvement of dysbiosis by administration of probiotics and prebiotics may enhance the rate of Tregs' increase, thus preventing frequent relapse.

Rituximab Induces Complete Remission of Proteinuria in a Patient With Minimal Change Disease and No Detectable B Cells

Minimal change disease (MCD) is a common cause of nephrotic syndrome. Treatment with steroids is usually effective, but frequent relapses are therapeutic challenges. The anti-CD20 antibody rituximab has shown promising results for treatment of steroid-sensitive nephrotic syndrome. Since predictive biomarkers for treatment efficacy and the accurate rituximab dosage for effective induction of remission are unknown, measurement of CD19⁺ B cells in blood is often used as marker of successful B cell depletion and treatment efficacy. A male patient with relapsing MCD was successfully treated with rituximab, but developed relapse of proteinuria 1 year later, although no B cells were detectable in his blood. B and T cell populations in the patient’s blood were analyzed before and after treatment with rituximab using FACS analysis. Rituximab binding to B and T cells were measured using Alexa Fluor 647 conjugated rituximab. We identified a population of CD20⁺ CD19⁻ cells in the patient’s blood, which consisted mostly of CD20⁺ CD3⁺ T cells. Despite the absence of B cells in the blood, the patient was again treated with rituximab. He developed complete remission of proteinuria and depletion of CD20⁺ T cells. In a control patient with relapsing MCD initial treatment with rituximab led to depletion of both CD20⁺ B and T cells. Rituximab induces remission of proteinuria in patients with MCD even if circulating B cells are absent. CD20⁺ T cells may play a role in the pathogenesis of MCD and might be a promising treatment target in patients with MCD.

Clinical Significance of Probiotics for Children with Idiopathic Nephrotic Syndrome

We previously reported that a decrease in butyrate-producing bacteria in the gut is a potential cause of regulatory T cell (Treg) abnormalities in children with idiopathic nephrotic syndrome (INS). Therefore, we hypothesized that administration of butyrate-producing bacteria might reduce INS relapse and the need for immunosuppressants in these patients. Twenty patients in remission from INS (median age 5.3 years, 15 boys) were enrolled in the study and assigned to receive either daily oral treatment with a preparation of 3 g Clostridium butyricum or no probiotic treatment. The number of relapses and requirement for immunosuppressive agents were compared between the two groups. In the probiotic treatment group, analyses of the gut microbiota and Treg measurements were also performed. Probiotic-treated patients experienced fewer INS relapses per year compared with non-probiotic-treated patients (p = 0.016). Further, administration of rituximab in the probiotic treatment group was significantly less frequent compared with the non-probiotic-treated group (p = 0.025). In the probiotic treatment group, analyses before and after probiotic treatment revealed the significant increases in the relative abundance of butyrate-producing bacteria (p = 0.017) and blood Treg counts (p = 0.0065). Thus, oral administration of butyrate-producing bacteria during INS remission may reduce the frequency of relapse and the need for immunosuppressive agents.

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.

Plasma Cytokine Profiling to Predict Steroid Resistance in Pediatric Nephrotic Syndrome

Introduction

Glucocorticoids (GCs) are the primary treatment for nephrotic syndrome (NS), although ∼10% to 20% of children develop steroid-resistant NS (SRNS). Unfortunately, there are no validated biomarkers able to predict SRNS at initial disease presentation. We hypothesized that a plasma cytokine panel could predict SRNS at disease presentation, and identify potential pathways regulating SRNS pathogenesis.

Methods

Paired plasma samples were collected from 26 children with steroid-sensitive NS (SSNS) and 14 with SRNS at NS presentation and after ∼7 weeks of GC therapy, when SSNS versus SRNS was clinically determined. Plasma cytokine profiling was performed with a panel of 27 cytokines.

Results

We identified 13 cytokines significantly different in Pretreatment SSNS versus SRNS samples. Statistical modeling identified a cytokine panel (interleukin [IL]-7, IL-9, monocyte chemoattractant protein–1 [MCP-1]) able to discriminate between SSNS and SRNS at disease presentation (receiver operating characteristic [ROC] value = 0.846; sensitivity = 0.643; specificity = 0.846). Furthermore, GC treatment resulted in significant decreases in plasma interferon-γ (IFN-γ), tumor necrosis factor–α (TNF-α), IL-7, IL-13, and IL-5 in both SSNS and SRNS patients.

Conclusions

These studies suggest that initial GC treatment of NS reduces the plasma cytokines secreted by both CD4⁺ T_H1 cells and T_H2 cells, as well as CD8⁺ T cells. Importantly, a panel of 3 cytokines (IL-7, IL-9, and MCP-1) was able to predict SRNS prior to GC treatment at disease presentation. Although these findings will benefit from validation in a larger cohort, the ability to identify SRNS at disease presentation could greatly benefit patients by enabling both avoidance of unnecessary GC-induced toxicity and earlier transition to more effective alternative treatments.

Function of miR-24 and miR-27 in Pediatric Patients With Idiopathic Nephrotic Syndrome

Purpose: We investigated the pathogenesis of idiopathic nephrotic syndrome (INS) by measuring the effects two specific miRNAs on Th2 cells in children with this disease. Methods: After informed consent, we enrolled 20 children with active INS before steroid initiation, 20 children with INS in remission after steroid therapy, and 20 age-matched healthy controls. Flow cytometry was used to measure the levels of Th2 cells and a cytometric bead array was used to measure the levels of IgE, interleukin (IL)-4, and IL-13. RT-PCR was used to measure the levels of miR-24 and miR-27 in CD4⁺TCD25^- cells. PBMCs were isolated using Ficoll density gradient centrifugation, and transfected with different mimic or inhibitor miRNAs. RT-PCR was used to measure the expression of different RNAs, and flow cytometry was used to determine the percentage of Th2 cells. Results: Relative to healthy controls, children with active INS had higher percentages of Th2 cells (P < 0.05), but there was no significant difference in controls and children in remission. The plasma levels of IgE, IL-4, and IL-13 were significantly increased in children with active INS (P < 0.05). There were lower levels of miR-24 and miR-27 in children with active non-atopic INS (P < 0.05). Transfection experiments indicated that upregulation of each miRNA decreased the percentage of Th2 cells and the level of IL-4 (P < 0.05), and down-regulation of each miRNA had the opposite effects (P < 0.05). Conclusion: Children with active INS, with or without atopy, had higher levels of IgE, possibly related to their higher levels of IL-13 and IL-4 due to a drift toward Th2 cells. miR-24 and miR-27 suppressed the expression of Th2 cells and have a critical function regulating Th2 cell expression in INS.

A review of nephrotic syndrome and atopic diseases in children

Pediatric nephrotic syndrome (NS) is a common and recurrent glomerular disease in childhood. Furthermore, 50–70% of children with NS have increased total IgE in peripheral blood and a variety of clinical manifestations of atopic diseases. Hence, NS has many similarities with atopic diseases. However, no study has revealed a clear link between these two diseases. The present review discusses the correlation between pediatric NS and atopic diseases in children from three aspects: pathogenesis, cytokine change, and treatment. There are similar changes in T cells in terms of pathogenesis, with Th1/Th2 dysfunction and Treg cell function downregulation. Cytokine changes are similar and manifest as an increase in Th2 cytokines, TNF-α and TGF-β1, and a decrease in IL-10. Glucocorticoids, immunosuppressants and biological agents are used for the treatment of these two diseases. Therefore, it was speculated that NS and atopic diseases may be the same kind of disease, have a similar pathogenesis, and only exhibit different clinical manifestations due to different affected parts of the disease.

Case Report: Novel Dietary Supplementation Associated With Kidney Recovery and Reduction in Proteinuria in a Dialysis Dependent Patient Secondary to Steroid Resistant Minimal Change Disease

Minimal change disease (MCD) is the most common cause of nephrotic syndrome worldwide. For decades, the foundation of the treatment has been corticosteroids. However, relapse rate is high and up to 40% of patients develop frequent relapsing/steroid dependent course and one third become steroid resistant. This requires treatment with repeated courses of corticosteroids, and second and third line immunomodulators increasing the incidence of drug related adverse effects. More recently, there have been reports of a very small subset of Nephrotic Syndrome (NS) patients who are initially steroid sensitive and later become secondarily steroid resistant. The disease course in this small subset is often protracted leading ultimately to end stage kidney disease requiring dialysis or kidney transplantation. Unfortunately, patients with this disease course do not do well post transplantation because 80% of them will develop disease recurrence that will ultimately lead to graft failure. Few approaches have been tried over many years to reduce the frequency of relapses, and steroid dependence and there is absolutely no therapeutic intervention for patients who develop secondary steroid resistance. Nonetheless, their therapeutic index is low, evidencing the need of a safer complementary treatment. Several hypotheses, including an oxidative stress-mediated mechanism, and immune dysregulation have been proposed to date to explain the underlying mechanism of Minimal Change Disease (MCD) but its specific etiology remains elusive. Here, we report a case of a 54-year-old man with steroid and cyclosporine resistant MCD. The patient rapidly progressed to end stage kidney disease requiring initiation of chronic dialysis. Intradialytic parenteral nutrition (IDPN), albumin infusion along with a proprietary dietary supplement, as part of the supportive therapy, led to kidney function recovery and complete remission of MCD without relapses.

Multidimensional inflammatory and immunological endotypes of idiopathic focal segmental glomerulosclerosis and their association with treatment outcomes

Objectives

Idiopathic focal segmental glomerulosclerosis (FSGS) has been linked to immunological and inflammatory response dysregulations. The aim of this study was to find endotypes of FSGS patients using a cluster (CL) analysis based on inflammatory and immunological variables, and to analyse whether a certain endotype is associated with response to treatment with corticosteroids.

Methods

This prospective observational study included patients with idiopathic FSGS diagnosed by kidney biopsy. Serum levels of soluble interleukin (IL)-1 receptor, tumoural necrosis factor alpha, Interferon gamma (IFNγ), IL-6, IL-17, IL-12, IL-23, IL-13, IL-4, IL-5, IL-6, haemopexin (Hx), haptoglobin (Hgl), soluble urokinase-type plasminogen activator receptor (suPAR) and urinary CD80 (uCD80) were measured with enzyme-linked immunosorbent assay or nephelometry. T-helper lymphocyte populations and T-regulatory lymphocytes were analysed by flow cytometry. A factorial analysis followed by a k-means CL analysis was performed.

Results

A total of 79 FSGS patients were included. Three CLs were identified. CL1 (27.8%) included IL-12, IL-17, IL-23 and a T helper 17 (Th17) pattern. CL2 (20.2%) included IL-4, IL-5, IL-13, immunoglobulin E and Th2 pattern. CL3 (51.8%) included IL-6, Hx, Hgl, suPAR and uCD80. There were no differences in age, gender, kidney function, albumin or proteinuria among CLs. About 42/79 patients (53.1%) showed cortico-resistance. The prevalence of cortico-resistance was significantly lower in CL2 (4/16, 25%) than in CL1 (16/26, 72.7%) and CL3 (22/41, 53.7%) (P = 0.018), with no significant differences between CLs 1 and 3 (P = 0.14).

Conclusions

Patients with FSGS and indistinguishable clinical presentation at diagnosis were classified in three distinct CLs according to predominant Th17, Th2 and acute inflammatory responses that display differences in clinical response to treatment with corticosteroids.

The potentially therapeutic role of tonsillectomy in the alleviation of several renal diseases apart from IgA nephropathy

Tonsils are located mainly at the gateway of the respiratory tract, and are reportedly one of the secondary lymphatic organs of the immune system. The development of several diseases including IgA nephropathy (IgAN) is associated with inflammatory stimulation and an aberrant immune response of the tonsils. Several studies have reported an improvement in and/or an increase in the stability of the clinicopathological findings of patients with IgAN post tonsillectomy. However, the efficacy in and precise mechanism of the alleviation of symptoms of other renal diseases by tonsillectomy remain unknown. We hypothesize that tonsillectomy may play a potentially therapeutic role in renal diseases apart from IgAN, which are thought to be caused by an impaired regulation of the immune system.

Urinary CD80 Discriminates Among Glomerular Disease Types and Reflects Disease Activity

Introduction

Heterogeneity of nephrotic diseases and a lack of validated biomarkers limits interventions and reduces the ability to examine outcomes. Urinary CD80 is a potential biomarker for minimal change disease (MCD) steroid-sensitive nephrotic syndrome (NS). We investigated and validated a CD80 enzyme-linked immunosorbent assay (ELISA) in urine in a large cohort with a variety of nephrotic diseases.

Methods

A commercial CD80 ELISA was enhanced and analytically validated for urine. Patients were from Mayo Clinic (307) and Nephrotic Syndrome Study Network Consortium (NEPTUNE; 104) as follows: minimal change disease (MCD, 56), focal segmental glomerulosclerosis (FSGS, 92), lupus nephritis (LN, 25), IgA nephropathy (IgAN, 20), membranous nephropathy (MN, 49), autosomal dominant polycystic kidney disease (ADPKD, 10), diabetic nephropathy (DN; 106), pyuria (19), and controls (34). Analysis was by Kruskal−Wallis test, generalized estimating equation (GEE) models, and receiver operating characteristic (AUC) curve.

Results

Urinary CD80/creatinine values were highest in MCD compared to other glomerular diseases and were increased in DN with proteinuria >2 compared to controls (control = 36 ng/g; MCD = 139 ng/g, P < 0.01; LN = 90 ng/g, P < 0.12; FSGS = 66 ng/g, P = 0.18; DN = 63, P = 0.03; MN = 69 ng/g, P = 0.33; ng/g, P = 0.07; IgA = 19 ng/g, P = 0.09; ADPKD = 42, P = 0.36; and pyuria 31, P = 0.20; GEE, median, P vs. control). In proteinuric patients, CD80 concentration appears to be independent of proteinuria levels, suggesting that it is unrelated to nonspecific passage across the glomeruli. CD80/creatinine values were higher in paired relapse versus remission cases of MCD and FSGS (P < 0.0001, GEE).

Conclusion

Using a validated ELISA, urinary CD80 levels discriminate MCD from other forms of NS (FSGS, DN, IgA, MN) and primary from secondary FSGS.

[The balance of proinflammatory cytokines and Treg cells in chronic glomerulonephritis]

Chronic glomerulonephritis (CGN) is a disease with a steadily progressing course, which is based on inflammation with the activation of immune cells. The severity of the inflammatory reaction in the kidney tissue is determined by the balance of locally pro-inflammatory factors and protective mechanisms, which include anti-inflammatory cytokines and T-regulatory lymphocytes (Treg). The study of processes that can modulate the severity of inflammation in the kidney is of particular interest for understanding the basic patterns of CGN progression.

AIM

To determine the clinical significance of the Th17, Th1, and Treg cytokines in urine to assess the activity and progression of chronic glomerulonephritis with nephrotic syndrome (NS).

MATERIALS AND METHODS

The study included 98 patients with CGN 37 women and 61 men. Patients were divided into two groups according to the degree of CGN activity. Group I consisted of 51 patients with NS. In 21 subjects, a decrease in GFR60 ml/min was revealed. Group II included 47 patients with proteinuria from 1 to 3 g/day without NS. GFR60 ml/min/1.73 m2 was observed in 26 patients. A kidney biopsy was performed in 65 patients and the hystological diagnosis was verified: 20 had mesangioproliferative GN, 16 had membranous nephropathy, 18 had focal segmental glomerulosclerosis, and 11 had membranoproliferative GN. The control group consisted of 15 healthy people. The levels of IL-6, IL-10, IL-17, tumor necrosis factor a (TNF-a) in the urine were determined using enzyme-linked immunosorbent assay. The number of FoxP3-positive cells in the inflammatory interstitial infiltrate of the cortical layer was determined in 39 patients (in a biopsy sample in a 1.5 mm2 area).

RESULTS

In group of patients with CGN, there was an increase in the levels of Th17, Th1, and Treg cytokines in urine TNF-a and IL-10 compared with healthy individuals. An increase in the levels of IL-6 in the urine of patients with high clinical activity of CGN (with NS and renal dysfunction) was more pronounced than in patients with NS and normal renal function. There was a decrease in the number of Treg cells in the interstitium of the kidney and a decrease in the production of anti-inflammatory IL-10 in CGN patients with NS, compared with patients without NS. The most pronounced changes in the cytokine profile were observed in patients with FSGS with an increase in pro-inflammatory cytokines and a decrease in Treg in the kidney tissue/anti-inflammatory IL-10 in the urine.

CONCLUSION

An imbalance of cytokines characterized by an increased levels of pro-inflammatory IL-17, IL-6, TNF-a, and a reduced levels of anti-inflammatory IL-10 and T-regulatory cells in the kidney tissue is noted in patients with NS, especially with FSGS. Imbalance of cytokines reflects the high activity of CGN and the risk of the progression of the disease.

Long-term Successful Treatment of Rituximab for Steroid-resistant Minimal Change Nephrotic Syndrome and Idiopathic Thrombocytopenic Purpura

A 22-year-old woman had been diagnosed with idiopathic thrombocytopenic purpura (ITP) 5 years earlier. After undergoing splenectomy, she relapsed frequently following prednisolone tapering. She was complicated with minimal change nephrotic syndrome (MCNS) while taking 20 mg of prednisolone. Despite treatment with prednisolone, cyclosporin and low-density lipoprotein-apheresis, MCNS and ITP did not improve. We added rituximab in 4 weekly infusions of 375 mg/m². MCNS and ITP were in complete remission. After administering rituximab once, all medicines were discontinued. No relapse had occurred by 50 months following the first rituximab administration. Rituximab affects steroid-resistant MCNS and ITP for a long time without complications.

Corticosteroid reduction by addition of cetirizine and montelukast in biopsy-proven minimal-change nephrotic syndrome concomitant with allergic disorders

Recent reports suggest helper T-cell abnormalities in minimal-change nephrotic syndrome (MCNS), which often complicate allergic disorders that show a similar helper T-cell profile with Th2/Th17 predominance. However, the effect of anti-allergy therapy on MCNS remains unknown. This retrospective study included 51 patients with biopsy-proven MCNS recruited between November 2012 and October 2015, with follow-up through November 2017. We analyzed relapse and temporal daily corticosteroid dose with and without co-administration of histamine H1 receptor antagonist, cetirizine, and cysteinyl-leukotriene receptor antagonist, montelukast, as well as between baseline and after follow-up. Thirteen patients were treated with cetirizine and montelukast in addition to conventional therapy, whereas 38 patients were treated by conventional therapy only, consisting of corticosteroids and immunosuppressants. To adjust for baseline clinical characteristics, a 1:1 propensity score–matched model was applied. The clinical characteristics of the two groups after matching were similar at baseline. The treatment group showed a significant reduction in the lowest daily dose of oral prednisolone throughout the entire treatment course after the study compared to that of baseline (p < 0.025), which was not observed in the control group (p = 0.37), and showed significantly higher percentage of patients establishing corticosteroid-free state for the first time throughout the entire treatment course by addition of cetirizine and montelukast compared to the control group (p < 0.025). The study shows, for the first time, the steroid sparing effect of cetirizine and montelukast in addition to conventional treatment in MCNS patients with concomitant allergies.

Pathologic tonsillar findings similar to IgA nephropathy and the role of tonsillectomy in a patient with nephrotic syndrome

BACKGROUND

The pathological findings of tonsils in IgA nephropathy include the expansion of T-cell nodules around lymphoid follicles and abnormal reticulation of the crypt epithelium in contrast to chronic tonsillitis. Recently, several studies have reported that regulatory T cells play an important role in the maintenance of self-tolerance, an abnormality that is involved in the onset of nephrotic syndrome (NS). We encountered a patient of 28-year-old male with frequently relapsing nephrotic syndrome (FRNS) and chronic tonsillitis whose tonsils demonstrated pathological findings similar to those of IgA nephropathy.

CASE PRESENTATION

A patient had developed NS at the age of 5 years, and was pathologically diagnosed with minimal change disease (MCD), for which he received various immunosuppressive agents as treatment for recurrence. Because tonsillitis often triggers the recurrence of NS, a tonsillectomy was performed for chronic tonsillitis at the age of 25 years. Immunohistochemical staining of his tonsils showed the expansion of CD4 positive lymphocytes around the lymphoid follicles and abnormal reticulation of the crypt epithelium. The number of peripheral blood CD4+CD25+ regulatory T cells increased, and the frequency of relapses decreased after tonsillectomy.

CONCLUSION

A similar self-tolerance abnormality exists in NS and IgA nephropathy; therefore, tonsillectomy might become a novel therapeutic approach for FRNS to redress the unbalanced self-tolerance and to remove the tonsillar focal infection. Further studies are necessary to verify the clinical efficiency of tonsillectomy for FRNS with recurrent episodes triggered by tonsillitis.

Pediatric Patients With Steroid-Sensitive Nephrotic Syndrome Have Higher Expression of T Regulatory Lymphocytes in Comparison to Steroid-Resistant Disease

Background and Aim: Idiopathic nephrotic syndrome (INS) is classified according to the response to drug therapy in steroid-sensitive (SS), steroid-dependent (SD), and steroid-resistant (SR) categories. Previous studies showed changes in inflammatory activity of subpopulations of lymphocytes in INS. This study aimed to compare SS and SR patients in regard to subpopulations of leukocytes, profile of regulatory lymphocytes, and migratory activity of lymphocyte subpopulations. Results obtained in INS patients were also compared to age and sex-matched healthy controls. Methods: This is a cross-sectional study including SS patients (n = 30), SR patients (n = 14), and controls (n = 10). Peripheral blood samples were withdrawn for ex-vivo leukocyte flow cytometry analysis. Results: Percentage of B-lymphocytes and natural killer (NK) cells were significantly reduced in SR patients when compared to controls, while the percentage of NKT cells were decreased in SS patients in comparison to controls. Percentages of CD4⁺ expressing FoxP3 and CTLA4 were significantly higher in SS patients in comparison to SR patients and controls. The expression of integrin CD18 on the surface of T lymphocytes (CD3⁺) was reduced in SS patients if compared to controls. Conclusion: This study found that SS INS patients have higher levels of regulatory T-lymphocytes and lower expression of adhesion molecules than SR patients.

Efficacy and safety of mycophenolate mofetil versus levamisole in frequently relapsing nephrotic syndrome: an open-label randomized controlled trial

Both levamisole and mycophenolate mofetil (MMF) prevent relapses in patients with frequently relapsing nephrotic syndrome; however, their efficacy has not been compared prospectively. This single-center, randomized, open-label trial enrolled 149 children ages 6-18 years with frequently relapsing or steroid-dependent nephrotic syndrome. Participants were randomized in a 1:1 ratio to receive therapy with MMF (750-1000 mg/m² daily) or levamisole (2-2.5 mg/kg on alternate days) for 1 year; prednisolone was discontinued by 2-3 months. In intention-to-treat analyses, the frequency of relapse was similar between participants treated with MMF and levamisole (mean difference -0.29 relapses/patient-year; 95% confidence interval -0.65, 0.08). Relapse rates declined to almost one-third of baseline for both treatment groups. Therapy with MMF was not superior to levamisole in terms of the proportions of participants with sustained remission (40.8% vs. 34.2%), frequent relapses (14.5% vs. 16.4%), or treatment failure, a composite outcome of frequent relapses, steroid resistance, or significant steroid toxicity (15.8% vs. 20.6%). These outcomes were also similar in time to event analyses. Changes in anthropometry and blood pressure were similar between the groups, and the rates of adverse effects were low in both groups. Flow cytometry in 32 participants demonstrated similar proportions of B cells and CD4+, CD8+, T helper (Th)1, Th2, Th17, and T regulatory (Treg) cells during follow-up. Therapy with MMF was not superior to levamisole in the frequency of relapses, likelihood of sustained remission or corticosteroid sparing in children with frequently relapsing or steroid-dependent nephrotic syndrome. Registration CTRI/2012/02/002394.

Rituximab modulates T- and B-lymphocyte subsets and urinary CD80 excretion in patients with steroid-dependent nephrotic syndrome

BACKGROUND

Rituximab, a monoclonal antibody targeting B lymphocytes, effectively sustains remission in steroid-dependent nephrotic syndrome (SDNS). We studied its effects on lymphocyte subsets and urinary CD80 excretion (uCD80) in patients with SDNS.

METHODS

Blood and urine samples were collected from 18 SDNS patients before rituximab, and after 1 month and 1 year or at first relapse. T and B lymphocytes and uCD80 were determined by flow cytometry and ELISA, respectively.

RESULTS

Treatment was associated with reduction in counts of Th17, Th2, and memory T cells, and increased T-regulatory (Treg) cells. The Th17/Treg ratio declined from baseline (median 0.6) to 1 month (0.2, P = 0.006) and increased during relapse (0.3, P = 0.016). Ratios of Th1/Th2 cells at baseline, 1 month after rituximab, and during relapse were 7.7, 14.0 (P = 0.0102), and 8.7, respectively. uCD80 decreased 1 month following rituximab (45.5 vs. 23.0 ng/g creatinine; P = 0.0039). B lymphocytes recovered earlier in relapsers (60.0 vs.183.0 days; P < 0.001). Memory B cells were higher during relapse than remission (29.7 vs.18.0 cells/µL; P = 0.029).

CONCLUSION

Rituximab-induced sustained remission and B-cell depletion was associated with reduced numbers of Th17 and Th2 lymphocytes, and increased Treg cells; these changes reversed during relapses. Recovery of B cells and memory B cells predicted the occurrence of a relapse.

T-lymphocyte-expressing inflammatory cytokines underlie persistence of proteinuria in children with idiopathic nephrotic syndrome

OBJECTIVE

There is evidence of an important role of immune system changes in the triggering and maintenance of idiopathic nephrotic syndrome (INS). The aim of this study was to investigate the expression of cytokines in lymphocyte populations of patients with INS in comparison to healthy individuals, according to proteinuria.

METHODS

This cross-sectional study included 44 patients with INS and eight healthy children, matched for age and sex (controls). Patients were subdivided according to proteinuria: persistent proteinuria or partial remission (PP≥300mg/24h, n=17) and low proteinuria or complete remission (LP<300mg/24h, n=27). Ex vivo analysis of peripheral blood leukocytes by flow cytometry was performed using surface markers for T-lymphocytes, TCD4, TCD8, natural killer (NK) cells, NKT, and B-lymphocytes. Frequencies of intracellular cytokines were analyzed in these cells.

RESULTS

The frequencies of B-lymphocytes, NK cells, and NKT cells were lower in INS than in controls, whereas INS patients had a higher frequency of CD4⁺tumor necrosis factor (TNF)-α⁺ cells than controls. Cytotoxic-T-lymphocytes expressing IFN-γ were lower in INS than in controls. Patients with PP showed higher frequencies of CD4-T-lymphocytes expressing IFN-γ and TNF-α than controls. CD8-lymphocytes expressing TNF-α were increased in PP group when compared with LP and controls, while CD8⁺interferon (IFN)-γ⁺ cells were lower than in LP and in controls.

CONCLUSION

Regardless the level of proteinuria, INS patients had increased expression of TNF-α in CD4-lymphocytes and reduced expression of IFN-γ in CD8-lymphocytes. Persistence of proteinuria was associated with higher levels of inflammatory markers.

Molecular and Cellular Mechanisms for Proteinuria in Minimal Change Disease

Minimal Change Disease (MCD) is a clinical condition characterized by acute nephrotic syndrome, no evident renal lesions at histology and good response to steroids. However, frequent recurrence of the disease requires additional therapies associated with steroids. Such multi-drug dependence and frequent relapses may cause disease evolution to focal and segmental glomerulosclerosis (FSGS) over time. The differences between the two conditions are not well defined, since molecular mechanisms may be shared by the two diseases. In some cases, genetic analysis can make it possible to distinguish MCD from FSGS; however, there are cases of overlap. Several hypotheses on mechanisms underlying MCD and potential molecular triggers have been proposed. Most studies were conducted on animal models of proteinuria that partially mimic MCD and may be useful to study glomerulosclerosis evolution; however, they do not demonstrate a clear-cut separation between MCD and FSGS. Puromycin Aminonucleoside and Adriamycin nephrosis are models of glomerular oxidative damage, characterized by loss of glomerular basement membrane polyanions resembling MCD at the onset and, at more advanced stages, by glomerulosclerosis resembling FSGS. Also Buffalo/Mna rats present initial lesions of MCD, subsequently evolving to FSGS; this mechanism of renal damage is clearer since this rat strain inherits the unique characteristic of overexpressing Th2 cytokines. In Lipopolysaccharide nephropathy, an immunological condition of renal toxicity linked to B7-1(CD80), mice develop transient proteinuria that lasts a few days. Overall, animal models are useful and necessary considering that they reproduce the evolution from MCD to FSGS that is, in part, due to persistence of proteinuria. The role of T/Treg/Bcells on human MCD has been discussed. Many cytokines, immunomodulatory mechanisms, and several molecules have been defined as a specific cause of proteinuria. However, the hypothesis of a single cell subset or molecule as cause of MCD is not supported by research and an interactive process seems more logical. The implication or interactive role of oxidants, Th2 cytokines, Th17, Tregs, B7-1(CD80), CD40/CD40L, c-Mip, TNF, uPA/suPAR, Angiopoietin-like 4 still awaits a definitive confirmation. Whole genome sequencing studies could help to define specific genetic features that justify a definition of MCD as a “clinical-pathology-genetic entity.”

Leptin, hs-CRP, IL-18 and urinary protein before and after treatment of children with nephrotic syndrome

We aimed to analyze the changes in plasma leptin, serum inflammatory factors and urinary protein in children with nephrotic syndrome before and after treatment and their clinical significance. A total of 28 children treated and diagnosed with nephrotic syndrome between November 2015 and October 2016 were selected as treatment group, while 25 healthy children were selected as control group. There were no statistically significant differences in age, sex, body mass index (BMI), serum albumin and other general data between treatment group and control group (P>0.05). There was a positive correlation between serum high-sensitivity C-reactive protein (hs-CRP) level and 24 h urinary protein level in children with nephrotic syndrome before treatment (r=0.408, P=0.005). Twenty-four hours urinary protein, urea nitrogen (BUN) and serum creatinine (SCr) levels in children with nephrotic syndrome before treatment were significantly higher than those in normal children, and these indexes were significantly decreased after treatment. The levels of plasma leptin and serum inflammatory factors (hs-CRP and IL-18) in children with nephrotic syndrome before treatment were obviously higher than those in normal children, and these indexes were obviously decreased after treatment. In conclusion, the detection of changes in plasma leptin, serum inflammatory factors (hs-CRP and IL-18) and urinary protein in children with nephrotic syndrome before and after treatment has important reference value for reflecting the severity of disease and evaluating the prognosis of children with nephrotic syndrome.

NEPHRUTIX: A randomized, double-blind, placebo vs Rituximab-controlled trial assessing T-cell subset changes in Minimal Change Nephrotic Syndrome

Minimal-change nephrotic syndrome (MCNS) is an immune-mediated glomerular disease. We have analyzed the modifications on T-cell subsets in twenty-three patients who were highly steroid/calcineurin inhibitor and/or mycophenolate mofetil-dependent for frequently relapsing nephrotic syndrome (FRNS) and who were enrolled in a multicenter, double-blind, randomized, placebo vs Rituximab-controlled trial. Patients with FRNS entered the trial at remission and were randomly assigned to receive either Rituximab or placebo. In both groups, patient blood samples were analyzed at inclusion and then monthly until six months post-perfusion. Disclosure of patient's allocation code occurred in relapse or at the end of the trial. All patients under placebo displaying relapse were subsequently treated with Rituximab. Despite the significant decrease of immunosuppressive drugs, remission was maintained in all patients included in the Rituximab group, except one (n = 9/10). On the other hand, relapses occurred within a few weeks (means ≈ 7.3 weeks) in all patients receiving placebo (n = 13). At inclusion, before rituximab therapy, the frequency of different T-cell subsets were highly similar in both groups, except for CD8⁺ and invariant TCRVα24 T-cell subsets, which were significantly increased in patients of the Placebo group ((p = 0,0414 and p = 0.0428, respectively). Despite the significant decrease of immunosuppressive drugs, remission was maintained in all patients included in the Rituximab group (n = 10), except one. Relapses were associated with a significant decrease in CD4⁺CD25^highFoxP3^high Tregulatory cells (p = 0.0005) and IL2 expression (p = 0.0032), while CMIP abundance was significantly increased (p = 0.03). Remissions after Rituximab therapy were associated in both groups with significant decrease in the frequency of CD4⁺CD45RO⁺CXCR5⁺, invariant natural killer T-cells (INKT) and CD4^-CD8^- (double-negative, DN) T-cells expressing the invariant Vα24 chain (DN-TCR Vα24) T-cells, suggesting that MCNS involves a disorder of innate and adaptive immune response, which can be stabilized by Rituximab treatment.

Analysis of T Cell Subsets in Adult Primary/Idiopathic Minimal Change Disease: A Pilot Study

AIM

To characterise infiltrating T cells in kidneys and circulating lymphocyte subsets of adult patients with primary/idiopathic minimal change disease.

METHODS

In a cohort of 9 adult patients with primary/idiopathic minimal change recruited consecutively at disease onset, we characterized (1) infiltrating immune cells in the kidneys using immunohistochemistry and (2) circulating lymphocyte subsets using flow cytometry. As an exploratory analysis, association of the numbers and percentages of both kidney-infiltrating immune cells and the circulating lymphocyte subsets with kidney outcomes including deterioration of kidney function and proteinuria, as well as time to complete clinical remission up to 48 months of follow-up, was investigated.

RESULTS

In the recruited patients with primary/idiopathic minimal change disease, we observed (a) a dominance of infiltrating T helper 17 cells and cytotoxic cells, comprising cytotoxic T cells and natural killer cells, over Foxp3+ Treg cells in the renal interstitium; (b) an increase in the circulating total CD8+ T cells in peripheral blood; and (c) an association of some of these parameters with kidney function and proteinuria.

CONCLUSIONS

In primary/idiopathic minimal change disease, a relative numerical dominance of effector over regulatory T cells can be observed in kidney tissue and peripheral blood. However, larger confirmatory studies are necessary.

Rituximab for Recurrence of Primary Focal Segmental Glomerulosclerosis After Kidney Transplantation: Clinical Outcomes

BACKGROUND

Rituximab has shown encouraging results for the treatment of kidney transplantation recipients with focal segmental glomerulosclerosis (FSGS) recurrence. However, the correct, opportune, and safe use of rituximab for this indication remains to be determined.

METHODS

This multicenter retrospective study reports on 19 new cases aged 35 (15-66) years who developed FSGS recurrence at 12 (1.5-27) days posttransplantation. Initial treatment consisted of plasma exchanges (PE), high doses of calcineurin inhibitors, and steroids. Rituximab was introduced either immediately (N = 6) or after failure of the initial treatment (N = 10) or failed attempted weaning from PE (N = 3).

RESULTS

Overall, we observed 9 of 19 complete remissions and 3 of 19 partial remissions. Estimated glomerular filtration rates (Modification of Diet in Renal Disease 4) were significantly higher in the responding patients than in nonresponding patients at month (M)12, M36, and M60. Overall, kidney survival at 5 years was 77.4% (95% range, 41.9-92.7). The 5-year graft survival rates in the responding patients and the nonresponding patients were 100% and 36.5%, respectively (P = 0.01). A further course of rituximab was required for 4 patients as a result of FSGS relapse, with good results. During the first year after renal transplantation, 14 patients developed severe infections (16 bacterial, 4 viral, 1 parasitic).

CONCLUSIONS

In kidney transplantation recipients with recurrent FSGS, rituximab therapy may be a recommended treatment for cases that have failed either the initial treatment or weaning from PE.

Regulatory T cells and CTLA-4 in idiopathic nephrotic syndrome

The pathogenesis of idiopathic nephrotic syndrome (INS) remains unknown. Recently, it was postulated that suppression of regulatory T cells (Treg) leads to massive proteinuria in INS, although there is some controversy. Considering the important role of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) in Treg-mediated immune suppression, the aim of this study was therefore to clarify the involvement of Treg and CTLA-4 in the pathogenesis of INS. Fifteen patients with INS were enrolled. Their blood was sampled twice, once at onset and once at remission induced by glucocorticoid. Although median Treg number was significantly lower at onset than in healthy children, it increased at remission. Similarly, serum CTLA-4 concentration significantly increased at remission compared with onset. Furthermore, a positive significant correlation was observed between Treg number and serum CTLA-4 level. This suggests that Treg and CTLA-4 are involved in the induction of remission in INS.

Rituximab for nephrotic syndrome in children

Idiopathic nephrotic syndrome is the most common chronic glomerular disease in children. At least 20 % of children with this syndrome show frequent relapses and/or steroid dependence during or after immunosuppressive therapies, a condition defined as complicated frequently relapsing/steroid-dependent nephrotic syndrome (FRNS/SDNS). Approximately 1-3 % of children with idiopathic nephrotic syndrome are resistant to steroids and all immunosuppressive agents, a condition defined as refractory steroid-resistant nephrotic syndrome (SRNS); these SRNS children have a high risk of end-stage renal failure. Rituximab, a chimeric anti-CD20 monoclonal antibody, has been shown to be effective for patients with complicated FRNS/SDNS and refractory SRNS. This review describes the recent results of rituximab treatment applied to pediatric nephrotic syndrome, as well as those of our recent study, a multicenter, double-blind, randomized, placebo-controlled trial of rituximab for childhood-onset complicated FRNS/SDNS (RCRNS01). The overall efficacy and safety of rituximab for this disease are discussed.

Rituximab in Minimal Change Disease: Mechanisms of Action and Hypotheses for Future Studies

Treatment with rituximab, a monoclonal antibody against the B-lymphocyte surface protein CD20, leads to the depletion of B cells. Recently, rituximab was reported to effectively prevent relapses of glucocorticoid-dependent or frequently relapsing minimal change disease (MCD). MCD is thought to be T-cell mediated; how rituximab controls MCD is not understood. In this review, we summarize key clinical studies demonstrating the efficacy of rituximab in idiopathic nephrotic syndrome, mainly MCD. We then discuss immunological features of this disease and potential mechanisms of action of rituximab in its treatment based on what is known about the therapeutic action of rituximab in other immune-mediated disorders. We believe that studies aimed at understanding the mechanisms of action of rituximab in MCD will provide a novel approach to resolve the elusive immune pathophysiology of MCD.

Apolipoprotein C-I Levels Are Associated with the Urinary Protein/Urinary Creatinine Ratio in Pediatric Idiopathic Steroid-Sensitive Nephrotic Syndrome: A Case Control Study

Humoral factors may cause idiopathic steroid-sensitive nephrotic syndrome (ISSNS). In the present study, we analyzed serum proteins using mass spectrometry (MS) to identify proteins associated with the pathophysiology of pediatric ISSNS. We collected serial serum samples from 33 children during each ISSNS phase; Phase A1 is the acute phase prior to steroid treatment (STx), Phase A2 represents the remission period with STx, and Phase A3 represents the remission period after completion of STx. Children with normal urinalyses (Group B) and children with a nephrotic syndrome other than ISSNS (Group C) served as controls. No significant differences in urinary protein/urinary creatinine (UP/UCr) ratios were observed between the children with phase A1 ISSNS and Group C. We used surface-enhanced laser desorption/ionization time of flight MS for sample analysis. Four ion peaks with a mass-to-charge ratio (m/z) of 6,444, 6,626, 8,695, and 8,915 were significantly elevated during ISSNS Phase A1 compared to Phase A2, Phase A3, and Group C. The intensity of an m/z of 6,626 significantly correlated with the UP/UCr ratio and an m/z of 6,626 was identified as apolipoprotein C-I (Apo C-I). Apo C-I levels correlate with the UP/UCr ratio in pediatric ISSNS. Our findings provide new insights into the pathophysiology of ISSNS.