Increased IL-2, IL-4 and interferon-gamma (IFN-gamma) in steroid-sensitive nephrotic syndrome

Swollen Feet: Considering the Paradoxical Roles of Interleukins in Nephrotic Syndrome

Interleukins are a family of 40 bioactive peptides that act through cell surface receptors to induce a variety of intracellular responses. While interleukins are most commonly associated with destructive, pro-inflammatory signaling in cells, some also play a role in promoting cellular resilience and survival. This review will highlight recent evidence of the cytoprotective actions of the interleukin 1 receptor (IL-1R)- and common gamma chain receptor (IL-Rγc)-signaling cytokines in nephrotic syndrome (NS). NS results from the injury or loss of glomerular visceral epithelial cells (i.e., podocytes). Although the causes of podocyte dysfunction vary, it is clear that pro-inflammatory cytokines play a significant role in regulating the propagation, duration and severity of disease. Pro-inflammatory cytokines signaling through IL-1R and IL-Rγc have been shown to exert anti-apoptotic effects in podocytes through the phosphoinositol-3-kinase (PI-3K)/AKT pathway, highlighting the potential utility of IL-1R- and IL-Rγc-signaling interleukins for the treatment of podocytopathy in NS. The paradoxical role of interleukins as drivers and mitigators of podocyte injury is complex and ill-defined. Emerging evidence of the cytoprotective role of some interleukins in NS highlights the urgent need for a nuanced understanding of their pro-survival benefits and reveals their potential as podocyte-sparing therapeutics for NS.

Scaffold protein SH3BP2 signalosome is pivotal for immune activation in nephrotic syndrome

Despite clinical use of immunosuppressive agents, the immunopathogenesis of minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remains unclear. Src homology 3-binding protein 2 (SH3BP2), a scaffold protein, forms an immune signaling complex (signalosome) with 17 other proteins, including phospholipase Cγ2 (PLCγ2) and Rho-guanine nucleotide exchange factor VAV2 (VAV2). Bioinformatic analysis of human glomerular transcriptome (Nephrotic Syndrome Study Network cohort) revealed upregulated SH3BP2 in MCD and FSGS. The SH3BP2 signalosome score and downstream MyD88, TRIF, and NFATc1 were significantly upregulated in MCD and FSGS. Immune pathway activation scores for Toll-like receptors, cytokine-cytokine receptor, and NOD-like receptors were increased in FSGS. Lower SH3BP2 signalosome score was associated with MCD, higher estimated glomerular filtration rate, and remission. Further work using Sh3bp2KI/KI transgenic mice with a gain-in-function mutation showed ~6-fold and ~25-fold increases in albuminuria at 4 and 12 weeks, respectively. Decreased serum albumin and unchanged serum creatinine were observed at 12 weeks. Sh3bp2KI/KI kidney morphology appeared normal except for increased mesangial cellularity and patchy foot process fusion without electron-dense deposits. SH3BP2 co-immunoprecipitated with PLCγ2 and VAV2 in human podocytes, underscoring the importance of SH3BP2 in immune activation. SH3BP2 and its binding partners may determine the immune activation pathways resulting in podocyte injury leading to loss of the glomerular filtration barrier.

A Case of Minimal Change Disease after SARS-CoV-2 Vaccination under the Age of 18

This is a care report of a 16-year-old-male who developed de novo minimal change disease following the second dose of the Pfizer vaccine. The patient developed sudden onset edema and 10 kg weight gain. He had nephrotic range proteinuria with normal renal function. Kidney biopsy with adequate sample confirmed minimal change disease. The patient improved after 1 week of starting prednisone. This is the first case of minimal change disease after the Pfizer vaccine in the teenager population since expanding the age groups to allow younger subjects to receive the vaccine. Reporting cases at different age groups will help in trying to clarify whether the increasing reports of nephrotic syndrome following the vaccination are accidental or cause–effect relationship.

Genetic Variants of Interleukin-4 in Romanian Patients with Idiopathic Nephrotic Syndrome

Background and objectives: One of the most frequent glomerular diseases in the pediatric population is represented by the idiopathic nephrotic syndrome (INS). The exact mechanisms mediating the disease are still unknown, but several genetic factors have been studied for possible implications. Cytokines are considered to play a pivotal role in mediating INS disease progression, interleukin-4 (IL-4) exhibiting particular interest. The objective of this research project was to investigate the association between two IL-4 gene single-nucleotide polymorphisms (SNPs) and INS susceptibility as well as response to steroid therapy, in a group of Romanian children. Materials and Methods: In total, 75 patients with INS and 160 healthy controls of Romanian origin were genotyped for IL-4 rs2243250/−590C/T and rs2070874/−34C/T using real-time polymerase chain reaction. Association tests were performed using the DeFinetti program and Plink 1.07 software and p-values < 0.05 were considered statistically significant. Results: The analysis of INS patients and controls revealed a similar genotype distribution of the studied SNPs. The minor T alleles were less frequent in the INS group, but not statistically significant (p = 0.1, OR = 0.68 and p = 0.2, OR = 0.74). Regarding the response to steroids, a low frequency of 590*T allele in steroid-resistant patients (7.7%), compared with steroid-sensitive patients (14%) and controls (17.5%), was obtained, but the difference did not reach the statistical significance threshold. The same result was obtained for −34C/T SNP. Conclusions: This is the first study examining the relationship between the IL-4 gene and INS susceptibility conducted in a European population, and particularly in Romania. The investigated SNPs were found to not be associated with disease susceptibility or response to the steroid treatment of pediatric INS.

The Role of Cytokines in Nephrotic Syndrome

Idiopathic nephrotic syndrome (INS) is an important primary glomerular disease characterized by severe proteinuria. Evidence supports a role for T cell dysfunction in the pathogenesis of INS. Glucocorticoids are the primary therapy for INS; however, steroid-resistant NS (SRNS) patients are at a higher risk of drug-induced side effects and harbor poor prognosis. Although the exact mechanism of the resistance is unknown, the imbalances of T helper subtype 1 (Th1), Th2, and regulatory T cells (Tregs) and their cytokines may be involved in the pathogenesis of glucocorticoid responsiveness. Up to now, no confirmed biomarkers have been able to predict SRNS; however, a panel of cytokines may predict responsiveness and identify SRNS patients. Thus, the introduction of distinctive cytokines as novel biomarkers of SRNS enables both preventions of drug-related toxicity and earlier switch to more effective therapies. This review highlights the impacts of T cell population imbalances and their downstream cytokines on response to glucocorticoid responsiveness state in INS.

Effect of Huaiqihuang Granules Combined with Comprehensive Nursing on Children with Primary Nephrotic Syndrome

Background

To observe the effect of Huaiqihuang granules combined with comprehensive nursing intervention on children with primary nephrotic syndrome (PNS) and its effect on renal function index.

Methods

A total of 104 patients were included, and the patients were randomly divided into two groups, with 52 cases in each group. The control group was treated with glucocorticoid, and the study group was treated with Huaiqihuang granules. The clinical efficacy of the two groups was observed. The levels of TG, TC, EGFR, 24 h UTP, BUN, Scr, IgA, IgG, IgM, IFN-γ and TNF-α were compared between two groups before and after treatment. The incidence of adverse reactions and recurrence rate after treatment were compared between the two groups.

Results

The effective rate of the study group (94.23%) was significantly higher than that of the control group (78.85%). Before treatment, there was no significant difference in TG and TC levels between the two groups. After treatment, the levels of TG and TC in both groups were decreased, and the decrease was more obvious in the study group. Compared with before treatment, the levels of 24 h UTP, BUN, Scr, IFN-γ, and TNF-α in both groups were significantly decreased after treatment, while EGFR, IgA, IgG, and IgM levels were significantly increased. Compared with the control group, the changes of each index in the study group were more obvious after treatment. After treatment, the incidence of adverse reactions and recurrence rate in the study group were significantly lower than those in the control group.

Conclusions

Huaiqihuang granules combined with comprehensive nursing treatment in children with PNS can reduce the occurrence of recent recurrence and adverse reactions and improve the cellular immune function and renal function.

A Novel Model for Nephrotic Syndrome Reveals Associated Dysbiosis of the Gut Microbiome and Extramedullary Hematopoiesis

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

Activation of the acute inflammatory phase response in idiopathic nephrotic syndrome: association with clinicopathological phenotypes and with response to corticosteroids

BACKGROUND

Data on the activation of the acute inflammatory response and its clinicopathological associations in idiopathic nephrotic syndrome (INS) are scarce and discordant.

OBJECTIVE

To analyse the associations between the activation of the inflammatory response, the clinicopathological characteristics of disease and the response to treatment with steroids in patients with INS.

METHODS

A total of 101 patients with INS due to minimal change disease (MCD; n = 44), focal segmental glomerulosclerosis (FSGS; n = 33) and membranous nephropathy (MN; n = 24) and 50 healthy controls were included. At diagnosis, we measured the levels of haemopexin (Hx), haptoglobin (Hgl), interleukin-6 (IL-6), soluble urokinase-type plasminogen activator receptor (suPAR), tumour necrosis factor-α (TNF-α), soluble IL-1 receptor, interferon-γ and C-reactive protein. We analysed their clinicopathological associations. In MCD and FSGS patients, we determined the association between the levels of these variables and steroid resistance.

RESULTS

The levels of Hx, Hgl, TNF-α, suPAR and IL-6 were higher in patients with INS than in healthy controls, and were not associated with proteinuria, estimated glomerular filtration rate or serum albumin. In MCD and FSGS patients, Hx, Hgl, IL-6 and TNF-α levels were similar and significantly higher than in MN patients. In patients with MCD and FSGS, multivariate analyses identified FSGS and the levels of Hx, Hgl or IL-6 as independent predictors of steroid resistance.

CONCLUSIONS

The activation of the inflammatory response in patients with INS is heterogeneous and more prevalent in MCD or FSGS patients than in those with MN. In MCD and FSGS, elevated levels of Hx, Hgl or IL-6 are independently associated with steroid resistance.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.

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.

Atypical thymic carcinoid manifesting with nephrotic-range proteinuria in a 7-year-old boy

BACKGROUND

Nephrotic-range proteinuria as a paraneoplastic syndrome (PNS) is an exceptional presentation, especially in children. It is usually associated with hematologic malignancies. Solid tumors are very rare causes of proteinuria.

CASE-DIAGNOSIS/TREATMENT

We present the case of a 7-year-old boy with an extremely rare atypical thymic carcinoid accompanied by nephrotic-range proteinuria as PNS. The kidney biopsy was consistent with minimal change disease (MCD). Tests for a neuroendocrine tumor were performed due to symptoms of hypercortisolemia and an elevated concentration of chromogranin A in the serum. The chest computed tomography revealed a tumor in the anterior mediastinum, which was diagnosed as an atypical thymic carcinoid. A complete resolution of the nephrotic-range proteinuria was observed within 1 week after the first thoracoscopic surgery, with almost complete reduction of the tumor mass.

CONCLUSIONS

This extremely rare case shows that MCD can occur as a PNS even in children. Nephrotic-range proteinuria can be a symptom of malignant solid tumor. This case highlights the possibility of secondary causes of MCD in children.

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.

Urinary excretion of IL-1β, IL-6 and IL-8 cytokines during relapse and remission of idiopathic nephrotic syndrome

BACKGROUND/AIM

The role of pro-inflammatory cytokines in the immunopathogenesis of idiopathic nephrotic syndrome had been widely postulated. Reports on the release of cytokines, during idiopathic nephrotic syndrome (INS) activation, were conflicting in defining a specific interleukin pattern during relapse and remission of the disease. The aim of this study was to explore the role of IL-1β, IL-6 and IL-8 in the pathophysiology of INS during relapse and remission.

PATIENTS AND METHODS

A total of 37 INS patients were included. Their demographic and biochemical data were reviewed. Levels of IL-1β, IL-6 and IL-8 were measured in the urine of patients during relapse and remission of the disease. Urine samples from 30 age- and sex-matched controls were checked for the same 3 cytokines.

RESULTS

Mean age of patients at study was 6.4 ± 3.2 years (range: 14 months-12 years). Male:female ratio was 24:13. Mean serum creatinine was 47 ± 13 μmol/L, and mean serum albumin was 21 ± 7 g/L. Mean urinary IL-1β, IL6 and IL8 levels, corrected to urinary creatinine, in patients during relapse were 132.94 ± 654.97, 217.82 ± 1124.31 and 150.227 ± 523.97 pg/μmol compared to 9.11 ± 40.75, 0.146 ± 0.652, and 6.455 ± 24.53 pg/μmol in controls, respectively (P = 0.02, 0.03 and 0.014, respectively). No significant difference was reported in the mean level of the 3 cytokines compared to controls during remission (P = 0.94, 0.092 and 0.076).

CONCLUSION

Our results support the role of T-cell activation and the subsequent release of IL-1β, IL6 and IL8 in the pathogenesis of relapses in INS. The use of steroid-sparing cytokine blockers in managing relapses of INS remains a tempting challenge.

Correlation Between Idiopathic Nephrotic Syndrome and Atopy in Children - Short Review

The idiopathic nephrotic syndrome is a common chronic kidney diseases in children defined by the association of massive proteinuria and hypoalbuminemia in a relapsing/remission course, with histological aspect of minimal changes (also called minimal change disease) in the majority of the cases, but its pathogenesis remains not very well known. Clinical and immunological studies have consistently shown a relationship between atopic diathesis, immunoglobulin E and cytokines involved in immunoglobulin E synthesis and idiopathic nephrotic syndrome. Additional research is necessary to clarify this relationship and to explore the contribution of allergic disease to the development of nephrotic syndrome and to identify potential new strategies of diagnosis and treatment.

Elevation of plasma-soluble HLA-G in childhood nephrotic syndrome is associated with IgE

Background Nephrotic syndrome is related to immune system dysfunction. Soluble human leukocyte antigen-G has been suggested to have an immunomodulatory role. Additionally, human leukocyte antigen-G expression may be influenced by the 14-base pair insertion/deletion polymorphism. However, this molecule has not been investigated in nephrotic syndrome. Methods Fifty-five children with nephrotic syndrome were enrolled: 24 primary nephrotic syndrome patients and 31 recurrent nephrotic syndrome patients. A group of 120 healthy subjects were included as reference controls. Additionally, 22 patients in nephrotic syndrome remission after treatments were also included. Both nephrotic syndrome patients and healthy subjects were genotyped for the 14-base pair insertion/deletion polymorphism. Plasma soluble human leukocyte antigen-G concentrations and serum immunoglobulin concentrations were determined. Results Nephrotic syndrome patients showed significantly higher levels of both soluble human leukocyte antigen-G and immunoglobulin E compared to normal controls. Nephrotic syndrome patients presented a higher frequency of the -14-base pair allele than did normal controls. Soluble human leukocyte antigen-G concentrations in remission patients were dramatically lower compared to in nephrotic syndrome patients. Moreover, soluble human leukocyte antigen-G and immunoglobulin E were moderately correlated in nephrotic syndrome patients. Conclusions The present study demonstrated that plasma soluble human leukocyte antigen-G concentrations were significantly elevated and that a relationship between serum total immunoglobulin E in nephrotic syndrome patients and the human leukocyte antigen-G -14-base pair allele may be a risk factor for nephrotic syndrome. These findings suggest that soluble human leukocyte antigen-G may be used as a monitoring marker for nephrotic syndrome patients' condition.

T Lymphocyte Activation Markers as Predictors of Responsiveness to Rituximab among Patients with FSGS

BACKGROUND AND OBJECTIVES

Rituximab is used with variable success in difficult FSGS. Because B cell depletion significantly affects T cell function, we characterized T cell subsets in patients with FSGS to determine if an immunologic signature predictive of favorable response to rituximab could be identified.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty-two consecutive patients with FSGS (median age =14.4 years old; range =6.2-25.0 years old) and age of onset of nephrotic syndrome 1-18 years old receiving rituximab for clinical indications between October of 2009 and February of 2014 were studied. Indications for rituximab were lack of sustained remission despite calcineurin inhibitors (CNIs) and mycophenolate in steroid-resistant patients and lack of steroid-sparing effect with cyclophosphamide and CNI or CNI toxicity in steroid-dependent patients. Exclusion criteria were infantile onset, known genetic mutations, and secondary causes. Rituximab (375 mg/m(2)) was given fortnightly up to a maximum of four doses. Immunologic subset monitoring was performed at baseline and regular intervals until relapse. Median follow-up duration postrituximab was 26.7 months (range =6.5-66.5 months). Baseline immunologic subsets were examined for association with rituximab response defined as resolution of proteinuria with discontinuation of prednisolone and CNI 3 months postrituximab.

RESULTS

Twelve patients (54.5%) responded to rituximab. Mitogen-stimulated CD154(+)CD4(+)CD3(+) subset before rituximab was significantly lower in FSGS responders compared with nonresponders (54.9%±28.1% versus 78.9%±16.4%; P=0.03). IFN-γ(+)CD3(+) and IL-2(+)CD3(+) were similarly decreased in responders compared with nonresponders (0.6%±0.8% versus 7.5%±6.1%; P=0.003 and 0.2%±0.5% versus 4.0%±4.7%; P<0.01, respectively). Recovery of all three activation subsets occurred 6 months postrituximab treatment (CD154(+)CD4(+)CD3(+), 74.8%±17.2%; IFN-γ(+)CD3(+), 7.1%±7.7%; and IL-2(+)CD3(+), 7.9%±10.9%; P<0.01). Receiver-operating characteristic analysis using optimal cutoff values showed that activated CD154(+)CD4(+)CD3(+) <83.3% (area under the curve [AUC], 0.81; 95% confidence interval [95% CI], 0.61 to 1.00), IFN-γ(+)CD3(+)<2.5% (AUC, 0.90; 95% CI, 0.75 to 1.00), and IL-2(+)CD3(+)<0.3% (AUC, 0.78; 95% CI, 0.57 to 0.98) were good predictors of rituximab response.

CONCLUSIONS

We have identified prognostic markers that define a subset of patients with FSGS bearing an immunologic signature representing hyporesponsiveness to T cell stimulation and therefore, who respond better to rituximab.

Pathogenesis of minimal change nephrotic syndrome: an immunological concept

Idiopathic nephrotic syndrome (INS) in children is characterized by massive proteinuria and hypoalbuminemia. Minimal change nephrotic syndrome (MCNS) is the most common form of INS in children. The pathogenesis of MCNS still remains unclear, however, several hypotheses have been recently proposed. For several decades, MCNS has been considered a T-cell disorder, which causes the impairment of the glomerular filtration barrier with the release of different circulating factors. Increased levels of several cytokines are also suggested. Recently, a "two-hit" theory was proposed that included the induction of CD80 (B7-1) and regulatory T-cell (Treg) dysfunction, with or without impaired autoregulatory functions of the podocyte. In contrast to the well-established involvement of T cells, the role of B cells has not been clearly identified. However, B-cell biology has recently gained more attention, because rituximab (a monoclonal antibody directed against CD20-bearing cells) demonstrated a very good therapeutic response in the treatment of childhood and adult MCNS. Here, we discuss recent insights into the pathogenesis of MCNS in children.

Regulatory T cells and minimal change nephropathy: in the midst of a complex network

Minimal change nephrosis (MCN) is an important cause of morbidity in children. In spite of successful therapies having been developed in the last three decades, most aspects related to pathogenesis still remain poorly defined. Evolution in basic immunology and results deriving from animal models of the disease suggest a complex interaction of factors and cells starting from activation of innate immunity and continuing with antigen presentation. Oxidants, CD80 and CD40/CD40L have probably a relevant role at the start. Studies in animal models and in human beings also suggest the possibility that the same molecules (i.e. CD80, CD40) are expressed by podocytes under inflammatory stimuli, representing a direct potential mechanism for proteinuria. B and T cells could play a relevant role this contest. Implication of B cells is suggested indirectly by studies utilizing anti-CD20 monoclonal antibodies as the main therapy. The role of regulatory T cells (Tregs ) is supported mainly by results in animal models of nephrotic syndrome (i.e. adriamycin, puromycin, lipopolysaccharide), showing a protective effect of direct Treg infusion or stimulation by interleukin 2 (IL-2). Limited studies have also shown reduced amounts of circulating Tregs in patients with active MCN cells. The route from bench to bedside would be reduced if results from animal models were confirmed in human pathology. The expansion of Tregs with recombinant IL-2 and new anti-CD20 monoclonal antibodies is the beginning. Blocking antigen-presenting cells with cytotoxic T lymphocyte antigen (CTLA-4)-Ig fusion molecules inhibiting CD80 and/or with blockers of CD40-CD40 ligand interaction represent potential new approaches. The hope is that evolution in therapies of MCN could fill a gap lasting 30 years.

Glucocorticoid pharmacogenetics in pediatric idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome represents the most common type of primary glomerular disease in children: glucocorticoids (GCs) are the first-line therapy, even if considerable interindividual differences in their efficacy and side effects have been reported. Immunosuppressive and anti-inflammatory effects of these drugs are mainly due to the GC-mediated transcription regulation of pro- and anti-inflammatory genes. This mechanism of action is the result of a complex multistep pathway that involves the glucocorticoid receptor and several other proteins, encoded by polymorphic genes. Aim of this review is to highlight the current knowledge on genetic variants that could affect GC response, particularly focusing on children with idiopathic nephrotic syndrome.

Nonimmunologic targets of immunosuppressive agents in podocytes

Proteinuria is a characteristic finding in glomerular diseases and is closely associated with renal outcomes. In addition, therapeutic interventions that reduce proteinuria improve renal prognosis. Accumulating evidence has demonstrated that podocytes act as key modulators of glomerular injury and proteinuria. The podocyte, or glomerular visceral epithelial cell, is a highly specialized and differentiated cell that forms interdigitated foot processes with neighboring podocytes, which are bridged together by an extracellular structure known as the "slit diaphragm" (SD). The SD acts as a size- and charge-selective barrier to plasma protein. Derangement of SD structure or loss of SD-associated protein results in podocyte injury and proteinuria. During the past decades, several immune-modulating agents have been used for the treatment of glomerular diseases and for the reduction of proteinuria. Interestingly, recent studies have demonstrated that immunosuppressive agents can have a direct effect on the SD-associated proteins and stabilize actin cytoskeleton in podocyte and have therefore introduced the concept of nonimmunologic mechanism of renoprotection by immunomodulators. This review focuses on the evidence that immuno-modulating agents directly target podocytes.

Pathogenesis of childhood idiopathic nephrotic syndrome: a paradigm shift from T-cells to podocytes

BACKGROUND

Nephrotic syndrome is the most common cause of kidney disease in children, but its pathogenesis remains unclear. This article reviews the novel aspects of the mechanisms underlying massive proteinuria in minimal-change disease, which is the most common form of childhood nephrotic syndrome.

DATA SOURCES

This article integrates the findings of a PubMed database search for English language articles published in the past 40 years (from September 1974 to February 2014) using the key words "pathogenesis", "minimal change nephrotic syndrome" or "idiopathic nephrotic syndrome".

RESULTS

Unknown humoral factors associated with T-cell dysfunction have been thought to play an important role in the pathogenesis of minimal-change disease. However, recent findings are changing this paradigm, i.e., visceral glomerular epithelial cells (podocytes) may be involved via expression of molecules such as CD80 and angiopoietin-like 4.

CONCLUSIONS

Recent evidence suggests that minimal-change disease results from interactions between humoral factors and dysfunctional podocytes. In addition to immunosuppressant drugs that target lymphocytes, a biological agent such as an antibody against the abnormal molecule(s) expressed by podocytes may provide novel drug treatment for minimal-change disease.

Evaluation of children with steroid-sensitive nephrotic syndrome in terms of allergies

BACKGROUND

The etiology of minimal-change disease is not fully known, it is believed to be mediated by the immune system. Minimal-change disease also reported as having association with atopy. In this study, atopy history, the levels of serum IgE, and skin prick test in children with steroid-sensitive nephrotic syndrome were investigated.

METHODS

A group of 30 children (mean age 7.7 ± 2.2 years, 56.6% male) diagnosed with steroid-sensitive nephrotic syndrome were included in the study. Serum immunoglobulin E levels and eosinophil counts were evaluated in children with steroid-sensitive nephrotic syndrome both in relapse and remission. Skin prick test was performed in remission.

RESULTS

Of the 30 children investigated, 11 (36.7%) had a history of atopy. The median serum total IgE levels in nephrotic children in relapse, with (445 IU/mL) and without atopy (310 IU/mL) were significantly higher than those in remission (respectively, 200 IU/mL, p = 0.021, and 42 IU/mL, p = 0.001). The skin prick tests for all the allergens were evaluated as negative in all the patients.

CONCLUSION

It was thought that increased IgE may reflect the activation of immune mechanism following various stimuli rather than a direct association with atopy in children with steroid-sensitive nephrotic syndrome.

Nephrotic syndrome and Hodgkin lymphoma in children. Report of two cases

BACKGROUND

The association of nephrotic syndrome (NS) and Hodgkin's lymphoma (HL), although rare, is well recognised. In the majority of cases of HL, minimal change NS is detected.

DESCRIPTION OF CASES

This report presents the occurrence of NS in two children with HL. In the first case, NS preceded the diagnosis of lymphoma by 3 months, while in the other child, the two disorders occurred simultaneously. In both cases, clinical manifestations and laboratory parameters (proteinuria) of NS resolved after effective treatment for active HL.

CONCLUSION

Prolonged proteinuria may be a paraneoplastic syndrome and HL should be considered in the diagnosis as it is crucial for the management of both entities.

The role of the immune system in idiopathic nephrotic syndrome: a review of clinical and experimental studies

Idiopathic nephrotic syndrome (INS) is a multifactorial disease, characterized by proteinuria, hypoalbuminemia, edema and hyperlipidemia. Studies in humans and animal models have associated INS with changes in the immune response. The purpose of this article is to review clinical and experimental findings showing the involvement of the immune response in the pathogenesis of INS. The role of the immune system in INS has been shown by clinical and experimental studies. However, the pattern of immune response in patients with INS is still not clearly defined. Many studies show changes in the dynamics of T lymphocytes, especially the regulatory T cells. Alternatively, there are other reports regarding the involvement of the complement system and B lymphocytes in the pathophysiology of INS. Indeed, none of the immunological biomarkers evaluated were undeniably linked to changes in glomerular permeability and proteinuria. On the other hand, some studies suggest a link between urinary chemokines, such as IL-8/CXCL8 and MCP-1/CCL2, and changes in glomerular permeability and/or the deterioration of glomerulopathies. To understand the pathophysiology of INS, longitudinal studies are clearly needed. The characterization of the profile of the immune response might help the development of specific and individualized therapies, leading to clinical improvement and better prognosis.

Children with nephrotic syndrome have greater bone area but similar volumetric bone mineral density to healthy controls

BACKGROUND

Glucocorticoid use has been associated with an increased fracture risk and reduced bone mineral density (BMD), particularly in the trabecular compartment. However the contribution of the underlying inflammatory disease process to these outcomes is poorly understood. Childhood nephrotic syndrome (NS) typically follows a relapsing-remitting course often requiring recurrent courses of glucocorticoids, but with low systemic inflammation during remission. NS therefore represents a useful clinical model to investigate the effects of glucocorticoids on BMD and bone geometry in childhood.

METHODS

Children with NS were compared to age and sex matched healthy controls. Body composition and areal BMD (whole body, lumbar spine and hip) were assessed by DXA. Peripheral quantitative computed tomography (pQCT) scans were obtained at metaphyseal (4%) and diaphyseal (66%) sites of the tibia to determine volumetric BMD and bone cross-sectional geometry. Lifetime cumulative glucocorticoid exposure was calculated from medical records.

RESULTS

29 children with NS (55% male, age 10.7±3.1years) were compared to 29 healthy controls (55% male, age 11.0±3.0years). The children with NS were of similar height SDS to controls (p=0.28), but were heavier (0.65±1.28SDS vs -0.04±0.89SDS, p=0.022) and had greater body fat percentage SDS (0.31±1.01 vs -0.52±1.10, p=0.008). Tibial trabecular and cortical vBMD were similar between the two groups but bone cross-sectional area (CSA) was significantly greater in children with NS at both the metaphysis (954±234mm(2) vs 817±197mm(2), p=0.002) and diaphysis (534.9±162.7mm(2) vs 463.2±155.5mm(2), p=0.014). Endosteal and periosteal circumferences were greater in children with NS than controls (both p<0.01), resulting in reduced cortical thickness (2.4±0.7mm vs 2.8±0.7mm, p=0.018), but similar cortical CSA (p=0.22). The differences in cortical geometry were not statistically significant when weight was included as a confounding factor. There were no associations between cumulative steroid exposure, duration of NS or number of relapses and any bone parameter.

CONCLUSIONS

Tibial bone CSA is increased in children with NS. We speculate that this is a compensatory response to increased body weight. Defects in trabecular BMD were not identified in this cohort of children with NS.

CD19 + CD23+ B cells, CD4 + CD25+ T cells, E-selectin and interleukin-12 levels in children with steroid sensitive nephrotic syndrome

Background and methods

Soluble-lymphocyte subsets (sCD19 + CD23+ B cells and sCD4 + CD25+ T cells), soluble-adhesion molecules (sE-selectin) and interleukin-12 (sIL-12) were assayed to evaluate the pathogenesis of steroid sensitive nephrotic syndrome in 48 patients diagnosed with steroid sensitive nephrotic syndrome (SSNS) in active (AS) and remission stages (RS).

Results

The ratios of soluble CD19 and sCD19 + CD23 increased in patients with AS with respect to the patients with RS and controls (p < 0.05). Increased sCD19 + CD23 ratios were preserved in the patients with RS when compared with the controls (p < 0.05). Moreover, the ratios of sCD4 + CD25 lymphocyte subsets were not significantly different among the groups. Similarly, serum sIL-12 levels were not considerably disparate between the AS and RS. Serum sE-selectin levels were higher in the patients with AS relative to the controls (p < 0.01) and RS (p < 0.05). No significant correlations were noted between sE-selectin and lymphocyte subset ratios, serum sIL-12 and immunoglobulin levels. There was a positive correlation between sE-selectin, triglyceride (r = 0.757, p < 0.0001) and cholesterol (r = 0.824, p < 0.0001) levels in patients with the AS.

Conclusion

The present results indicate that the patients with SSNS appear to have abnormalities in sCD23 + CD19+ cells, defect in T regulatory cell activity, and injury in endothelial cells as indicated by the presence high sE-selectin. These abnormalities might play a role in the pathogenesis of nephrotic syndrome. sIL-12 seems to have no role in pathogenesis of nephrotic syndrome reflecting normal Th1 response.

Cyprinus carpio Decoction Improves Nutrition and Immunity and Reduces Proteinuria through Nephrin and CD2AP Expressions in Rats with Adriamycin-Induced Nephropathy

Cyprinus carpio decoction (CCD) is a well-known Chinese food medicine formula, accepted widely as a useful therapy in preventing edema and proteinuria caused by renal disease. However, the mechanism underlying this effect remains unclear. The current study investigated the potential mechanism of CCD in alleviating nephropathy induced by adriamycin (ADR) in rats. 70  eight-week-old Wistar rats were randomly divided into normal, model, fosinopril, YD, YG groups. All rats except for the normal group received 6.5 mg/kg·bw of ADR injection into the vena caudalis once. Different doses of CCD (11.3 and 22.5 g kg(-1)) were lavaged to rats in YD and YG groups, respectively. Then the serum biochemical values of the total protein (TP), albumin (ALB), blood urea nitrogen (BUN), creatinine (Cr), electrolyte levels, and the urinary protein (UP) content in 12 hr urine were measured. Interleukin-4 (IL-4) and interferon (INF-γ) were measured by enzyme-like immunosorbent assay (ELISA). The pathomorphological analysis was observed using light and electron microscopy, and the expressions of nephrin and CD2-associated protein (CD2AP) in renal tissues were determined by immunohistochemical assay. The results indicated that CCD can relieve ADR-induced nephropathy (ADN) by improving the nutrition status, regulating the immunity, and inhibiting proteinuria by increasing nephrin and CD2AP expressions.

Minimal change disease: a CD80 podocytopathy?

Minimal change disease is the most common nephrotic syndrome in children. Although the etiology of minimal change disease remains to be elucidated, it has been postulated that it is the result of a circulating T-cell factor that causes podocyte cytoskeleton disorganization leading to increased glomerular capillary permeability and/or changes in glomerular basement membrane heparan sulfate glycosaminoglycans resulting in proteinuria. Minimal change disease has been associated with allergies and Hodgkin disease. Consistent with these associations, a role for interleukin-13 with minimal change disease has been proposed. Furthermore, studies evaluating podocytes also have evolved. Recently, increased expression of CD80 (also termed B7-1) on podocytes was identified as a mechanism for proteinuria. CD80 is inhibited by binding to CTLA-4, which is expressed on regulatory T cells. Recently, we showed that urinary CD80 is increased in minimal change disease patients and limited studies have suggested that it is not commonly present in the urine of patients with other glomerular diseases. Interleukin-13 or microbial products via Toll-like receptors could be factors that induce CD80 expression on podocytes. CTLA-4 appears to regulate CD80 expression in podocytes, and to be altered in minimal change disease patients. These findings lead us to suggest that proteinuria in minimal change disease is caused by persistent CD80 expression in podocytes, possibly initiated by stimulation of these cells by antigens or cytokines.

Cytokine gene polymorphism in idiopathic nephrotic syndrome children

The pathogenesis of idiopathic nephrotic syndrome is not completely understood. We postulate that cytokine gene polymorphisms may influence susceptibility or clinical course in Idiopathic Nephrotic Syndrome. Polymorphisms of IL-4, IL-6, and TNF-α cytokines were investigated in 150 children with Idiopathic Nephrotic Syndrome and 569 healthy controls by using polymerase chain reaction and restriction fragment length polymorphism. On comparing patient with controls strong association were found for IL-6, TNF-α and IL-4 at allelic level (IL-6-G174C (G vs. C): P = <0.001; OR = 6.33, TNF-α-G308A (G vs. A): P = <0.001; OR = 1.99, IL-4-C590T (C vs. T): P = 0.048; OR = 1.38). Further when SR group was compared with SS group significant association was found at genotypic level in all the studied genetic polymorphisms. Studied cytokine gene polymorphisms may influence susceptibility to idiopathic nephrotic syndrome and might affect steroid response in INS patients.

T regulatory cell function in idiopathic minimal lesion nephrotic syndrome

The purpose of this study was to test the hypothesis that, in idiopathic minimal lesion nephrotic syndrome (IMLNS), the T regulatory (T reg) cell suppressor mechanism is deficient, thereby enhancing cytokine release by T effector cells. Twenty-one patients with IMLNS, eight healthy controls and two patients with nephrotic syndrome and membranoproliferative glomerulonephritis were studied. The percentage of T reg cells was similar in the healthy controls and in patients with IMLNS in relapse or in remission. Thymidine incorporation in autologous T effector cells, as well as expression of the regulatory cytokine interleukin (IL)-10, was significantly reduced in patients in relapse when compared with patients in remission and healthy subjects. IL-2 expression was also reduced in patients in relapse but did not achieve statistical significance. In a different set of experiments, T cells, from subjects with IMLNS in remission, when stimulated with antiCD3-antiCD28 antibodies, secreted increased levels of cytokines. No such increase in cytokines was observed when cells from healthy controls were stimulated with same mitogen. The impaired T reg cell function observed in these patients may have pathogenic and therapeutic implications, because it could explain the persistence of the proposed pathogenic cytokines observed in the patients with IMLNS.

Macrophage inflammatory protein-1beta and interleukin-8 associated with idiopathic steroid-sensitive nephrotic syndrome

BACKGROUND

The cytokines associated with idiopathic steroid-sensitive nephrotic syndrome (ISSNS) have not been identified definitively, because previous studies had variable sampling and population heterogeneity. To clarify the cytokines involved, serum cytokine levels were measured using uniform sampling in a homogeneous population.

METHODS

Five children meeting the following criteria were included: (i) ISSNS; (ii) selectivity index <0.1; (iii) paired sera obtained in the nephrotic phase before steroid treatment (STx; group A) and in the remission phase under STx (group B); (iv) no infection; and (v) no immunosuppressant. Control groups were as follows: group C, four children with ISSNS in the remission phase without STx; group D, five with normal urinalysis; group E, five with symptomatic secondary nephrotic syndrome before STx. Cytokine levels were measured using bead-based assay.

RESULTS

Serum macrophage inflammatory protein-1beta (MIP-1beta) levels were higher in group B compared to group A, and group C was lower than groups A and B. Serum interleukin-8 (IL-8) levels were higher in group A than in groups B and C, and groups B and C did not differ. With regard to both cytokine levels, there were no differences between groups C and D, and groups A and E.

CONCLUSION

Serum MIP-1beta and IL-8 are associated with the clinical status of ISSNS in children. A relationship between MIP-1beta and ISSNS has not been previously reported. The mechanism by which MIP-1beta and IL-8 affect ISSNS is unclear. Nevertheless, the present findings are an interesting starting point for further investigations into the pathophysiology of ISSNS in children.

Idiopathic nephrotic syndrome and atopy: is there a common link?

Numerous reports during the last 60 years have reported a strong association between idiopathic nephrotic syndrome and atopic disorders. Idiopathic nephrotic syndrome can be precipitated by allergic reactions and has been associated with both aeroallergens (pollens, mold, and dust) and food allergies. Patients with idiopathic nephrotic syndrome also may show increased serum immunoglobulin E (IgE) levels. A review of the literature suggests that although some idiopathic nephrotic syndrome cases may be associated with allergies, evidence that it is a type of allergic disorder or can be induced by a specific allergen is weak. Rather, it is likely that the proteinuria and increased IgE levels in patients with idiopathic nephrotic syndrome are caused by increased levels of interleukin 13 observed in these patients. Recent studies suggest that interleukin 13, a known stimulator of IgE response, may mediate proteinuria in patients with minimal change disease because of its ability to directly induce CD80 expression on the podocyte.

Focal and segmental glomerulosclerosis induced in mice lacking decay-accelerating factor in T cells

Heritable and acquired diseases of podocytes can result in focal and segmental glomerulosclerosis (FSGS). We modeled FSGS by passively transferring mouse podocyte-specific sheep Abs into BALB/c mice. BALB/c mice deficient in the key complement regulator, decay-accelerating factor (DAF), but not WT or CD59-deficient BALB/c mice developed histological and ultrastructural features of FSGS, marked albuminuria, periglomerular monocytic and T cell inflammation, and enhanced T cell reactivity to sheep IgG. All of these findings, which are characteristic of FSGS, were substantially reduced by depleting CD4+ T cells from Daf(-/-) mice. Furthermore, WT kidneys transplanted into Daf(-/-) recipients and kidneys of DAF-sufficient but T cell-deficient Balb/(cnu/nu) mice reconstituted with Daf(-/-) T cells developed FSGS. In contrast, DAF-deficient kidneys in WT hosts and Balb/(cnu/nu) mice reconstituted with DAF-sufficient T cells did not develop FSGS. Thus, we have described what we believe to be a novel mouse model of FSGS attributable to DAF-deficient T cell immune responses. These findings add to growing evidence that complement-derived signals shape T cell responses, since T cells that recognize sheep Abs bound to podocytes can lead to cellular injury and development of FSGS.

Immune mediators in idiopathic nephrotic syndrome: evidence for a relation between interleukin 8 and proteinuria

The pathogenesis of idiopathic nephrotic syndrome (INS) remains unknown. Several findings suggest a role for the immune system. This study aimed to evaluate immune mediators in INS by measuring plasma and urinary levels of transforming growth factor beta1 (TGF-beta1), monocyte chemoattractant protein-1 (MCP-1/CCL2), regulated on activation normal T-cell expressed and secreted (RANTES/CCL5) and IL-8 (IL-8/CXCL8) in pediatric patients with INS and in age-matched healthy controls. Patients were divided according to their response to corticosteroids: steroid-sensitive (SS, n = 8), or steroid-resistant (SR, n = 24). Immune mediators were also compared in regard with disease activity (relapse and remission). Immune mediators were measured by ELISA. Plasma TGF-beta1 levels in SR patients were approximately 2.8-fold higher than control values (p < 0.05). Urinary IL-8/CXCL8 was 2.9-fold higher in INS patients in relapse (proteinuria >100 mg/m2/24 h) when compared with patients in remission (p < 0.05), and levels had a positive correlation with individual proteinuria values (p < 0.05). Urinary IL-8/CXCL8 was significantly higher in relapsed SR than in SS patients in remission. No changes in MCP-1/CCL2 and RANTES/CCL5 levels were detected. Our findings suggest that IL-8/CXCL8 and TGF-beta1 are involved in the pathogenesis of INS: IL-8/CXCL8 associated with local changes in glomerular permeability and TGF-beta1 could be related to worse response to corticosteroids.

Urinary cytokines and steroid responsiveness in idiopathic nephrotic syndrome of childhood

BACKGROUND/AIM

Steroid-resistant nephrotic syndrome (SRNS) has been associated with activation of TGF-beta(1) and progression to chronic kidney disease. Steroid-sensitive nephrotic syndrome (SSNS) has been associated with activation of T-cells and favorable outcome. Our objective was to distinguish SRNS from SSNS and focal segmental glomerulosclerosis (FSGS) from minimal change disease (MCD) on the basis of urinary cytokine profile.

METHOD

We used a high-throughput cytokine array. ICAM-1 and TGF-beta(1) in urine and kidney tissue were evaluated by ELISA and immunohistochemistry (IHC), respectively.

RESULTS

Age, gender, race, body mass index, and glomerular filtration rate were similar among groups. There were no statistically significant differences between SRNS (n = 12) and SSNS (n = 12) in regard to the presence of hypertension, treatment with ACE inhibitors, and renal histology. Arrays detected a 1- to 5.5-fold increase in urinary cytokine expression in subjects with idiopathic nephrotic syndrome (INS) as compared to controls. Using ELISA, urinary excretion of ICAM-1 was significantly higher in INS subjects than in controls (control group, n = 12; p = 0.005), but it did not differentiate SRNS from SSNS, or FSGS from MCD. IHC failed to reveal differences in renal tissue expression of ICAM-1 among controls, SRNS and SSNS. There were no significant differences among controls, and patients with SRNS and SSNS in the urinary excretion of TGF-beta(1) (p = 0.21). However, urinary TGF-beta(1) levels were significantly higher in FSGS than in MCD (p = 0.03), and IHC showed increased immunoreactivity in FSGS.

CONCLUSION

Our data indicate that urinary TGF-beta(1) was able to differentiate between FSGS and MCD but was not a biomarker of steroid responsiveness.

Atopy in childhood idiopathic nephrotic syndrome

AIM

Aim of the study was to evaluate the immunoallergic pattern and their modulating serum cytokines in children with primary manifestation of nephrotic syndrome, in order to analyse the correlation with disease activity and the outcome of childhood NS.

MATERIALS AND METHODS

We have evaluated 72 children: 58 steroid-sensitive and 14 steroid-resistant; 42 subjects were the healthy controls. In all were measured serum: T cell-subset, cytokines by Th-1, Th-2, total IgE levels and specific IgE antibodies.

RESULTS

Of the 72 children investigated, 35 (48.6%) had either a history of atopy and/or elevated serum IgE; 14 of these children (40%) had clinical sign of an atopic disease (asthma, rhinitis, dermatitis) and 21 (60%) had elevated sIgE. The atopy was more frequent among SS than SRNS patients (52% versus 36%, p<0.05). The CD19 were significantly increased in nephrotic patients compared with controls. IL-4 levels were not different from those in normal control both in SS and SRNS patients, either in relapse than in remission. There was no correlation between the sIgE and IL-4 levels. Therefore, IL-5 and Il-13 levels were significantly higher in SSNS compared to controls, in both pre than posttreatment, and higher in atopic patients. Interestingly, IL-6 and IL-10 levels were significantly increased in SRNS pretreatment compared to posttreatment and controls and, only for IL-10, significantly higher in atopic patients.

CONCLUSION

In our study, only 40% of atopic children had a positive allergic history and 51.4% of the nephrotic children had normal sIgE levels, both pre and posttreatment, indicating different aetiologies, as immune mechanisms, in the pathogenesis of NS. Therefore, specific IgE antibodies were not related to disease activity, suggesting that IgE production might be co-incident in childhood NS. However, the increased production of IL-5 and IL-13 in atopic SSNS may indicate that these cytokines are involved in the enhanced production of sIgE while IL-4 have a role as controlling cytokine.

Decreased in vitro osteoblast proliferation and low turnover bone disease in nonuremic proteinuric patients

Patients with proteinuria, even those with normal glomerular filtration rate, often present abnormal bone histology. We evaluated bone histology and the in vitro proliferation of osteoblasts in samples obtained from 17 proteinuric patients with primary glomerulopathies. Histomorphometric analysis of bone biopsies was performed, and bone fragments were obtained for osteoblast culture, in which we evaluated cell proliferation. In comparison to controls, patients presented lower trabecular bone volume (20.9+/-14.5% vs 26.8+/-5.9%; P=0.0008); lower trabecular number (1.7+/-0.2/mm vs 2.0+/-0.3/mm; P=0.004); and greater trabecular separation (475.5+/-96.4 microm vs 368.3+/-86.2 microm, P=0.0002). We also found alterations in bone formation and resorption: lower osteoid volume (0.9+/-0.7% vs 2.0+/-1.4%; P=0.0022); lower osteoid thickness (6.4+/-2.8 microm vs 11.5+/-3.2 microm; P<0.0001); less mineralizing surface (4.6+/-3.1% vs 13.5+/-6.0%; P<0.0001); lower bone formation rate (0.03+/-0.04 microm(3)/microm(2)/day vs 0.09+/-0.05 microm(3)/microm(2)/day; P<0.0001); and greater osteoclast surface (0.35+/-0.6 vs 0.05+/-0.1%, P=0.0016). Mean in vitro osteoblast proliferation was lower in patients than in controls (910.2+/-437.1 vs 2261.0+/-1121.0 d.p.m./well, P=0.0016). Serum concentrations of 25-hydroxyvitamin-D(3) correlated negatively with proteinuria and positively with in vitro osteoblast proliferation. Our results demonstrate that nonuremic proteinuric glomerulonephritic patients present bone structure disorder, low bone formation and high bone resorption, as well as low osteoblast proliferation.

Blood T-cell repertoire in idiopathic nephrotic syndrome recurrence following kidney transplantation

Corticosteroid resistant idiopathic nephrotic syndrome (CR-INS) is a glomerulopathy that recurs after kidney transplantation in 30-50% of patients, suggesting the involvement of systemic albuminuric factors, probably produced by activated T cells. We investigated peripheral T-cell selection and expansion before and after transplantation to identify and characterize T-lymphocyte patterns potentially associated with INS recurrence. We used a combined qualitative and quantitative assessment of Vbeta mRNA alterations at the level of the complementary determining region 3-length distribution (CDR3-LD) of the T-cell receptor (TCR). Peripheral blood mononuclear cells (PBMC) were collected from 18 CR-INS patients (8 with recurrence and 10 without recurrence) on the day of transplantation as well as at 1 month, 1 year and 5 years after transplantation, and Vbeta transcriptomes were analyzed. Our data show that blood T cells from patients with INS recurrence display a TCR repertoire that is stable in time and has a similar level of CDR3-LD alterations as the T-cell repertoire of control patients, both before and after transplantation. These results suggest that the process of INS recurrence does not involve TCR activation or specific clonal expansion of T cells. However, these results do not exclude a role for T cells in the production of an albuminuric factor.

A case of unfulfilled expectations. Cytokines in idiopathic minimal lesion nephrotic syndrome

Idiopathic minimal lesion nephrotic syndrome (IMLNS) was proposed to be a disorder of T-cell dysfunction by Shalhoub in 1974. The mechanisms by which T-cells increase glomerular permeability have remained elusive (and unproven). There is evidence that IMLNS may be due to a circulating factor released from activated T-cells. In recent years, efforts have been made to identify this pathogenetic cytokine as well as to understand the mechanism(s) for the increased release of this factor. This review attempts to critically analyze the available published data. Using different methodologies, investigators have focused on the production of cytokines in patients with IMLNS during relapse and remission. This has resulted in a plethora of data without definitive conclusions. The pathogenetic cytokine has not been identified, and it is questionable whether there is a Th2 dominance in IMLNS. The review of the available data illustrates the difficulties encountered when one is studying the cytokine secretory pattern in patients with IMLNS. Differences in patient population, type of cells studies, sample preservation, and methodology used to measure cytokines are some of the factors that could account for the disparity of observed results.

Renal macrophage activation and Th2 polarization precedes the development of nephrotic syndrome in Buffalo/Mna rats

BACKGROUND

At 8 weeks, Buffalo/Mna rats spontaneously develop a nephrotic syndrome associated with focal segmental glomerulosclerosis (FSGS). We have previously demonstrated that this glomerulopathy recurs after renal transplantation, thus supporting the relevance of this rat model to human idiopathic nephrotic syndrome [1]. In this study, we describe renal immune abnormalities which appear in parallel to the initiation and progression of the spontaneous Buffalo/Mna nephropathy.

METHODS

Buffalo/Mna rat kidney samples were harvested before (4 weeks) and after the occurrence of proteinuria (at 10, 18, and 24 weeks, and at 12, 15, 18, and 24 months). Renal immune cell populations [total lymphocytes, macrophages, T, B, and natural killer (NK) cells] and the expression kinetics of various related cytokine [transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin (IL)-1, IL-2, IL-4, IL-6, IL-10, IL-12, and IL-13], chemokine [regulated upon activation, normal T cell expressed and secreted (RANTES) and monocyte chemoattractant protein-l (MCP-1)] and T-cell receptor beta (TCR beta) chain transcripts were studied serially during the course of the disease.

RESULTS

In the Buffalo/Mna kidneys, in parallel to the proteinuria, the focal and segmental glomerular lesions began to develop at 10 weeks (affecting 2.4 +/- 0.8% of glomeruli), increased in number, then in intensity (10.4 +/- 0.8% at 24 weeks, 14.6 +/- 2.3% at 12 months, and 28.9 +/- 7.4% at 18 months). Before the onset of the disease, at a nonproteinuric stage, the transcript expression analysis revealed a strong production of some macrophage-associated cytokines, particularly TNF-alpha (350-fold higher than control levels), which was corroborated by monocyte infiltration. A minor T-cell infiltrate (associated with an increase in Cbeta TCR transcripts), with a predominantly Th2 profile and the down-regulation of Th1 cytokines was also observed. These abnormal macrophage and T-cell patterns remained stable after the onset of the disease. No changes in chemokine and TGF-beta transcripts were observed during the initial stages of the disease.

CONCLUSION

Our data suggest that the Buffalo/Mna rat disease may be the result of an immunologic disorder, involving macrophages and Th2 lymphocytes. We hypothesize that this modified environment could result in the production of a factor deleterious to the glomeruli. Thus, this rat strain could provide a new model for the study of human nephrotic syndrome.

Proteinuria and Fusion of Podocyte Foot Processes in Rats after Infusion of Cytokine from Patients with Idiopathic Minimal Lesion Nephrotic Syndrome

BACKGROUND/AIMS

We report on the isolation of a factor secreted by peripheral blood mononuclear cells from patients with idiopathic minimal lesion nephrotic syndrome (IMLNS) in relapse and its effect on proteinuria and podocyte morphology in the rat.

METHODS

Peripheral blood mononuclear cells from patients with IMLNS (in relapse and in remission) and patients with focal segmental glomerulosclerosis were cultured for 72 h. Supernatants from 20 x 10(6) cultured cells were separated by liquid chromatography into three fractions according to markers (bovine serum albumin, beta-amylase, and apoferritin). Each supernatant fraction was infused into rats for 5 days using an osmotic pump. Proteinuria, 24-hour albumin excretion or albumin/creatinine ratio in a 24-hour urine collection, was measured daily starting 3 days prior to fraction infusion. Renal tissue was obtained for electron microscopy studies. The beta-amylase fraction underwent electrophoresis using isoelectric focusing gel.

RESULTS

When protein excretion was compared prior to and during supernatant fraction infusion, a significant increase in proteinuria was observed only when beta-amylase fraction from IMLNS patients in relapse was infused (p < 0.05). Protein electrophoresis of the beta-amylase fraction showed a single band at pH 6.0 only in samples from IMLNS patients in relapse. The band was composed of two proteins, beta-amylase and a 100-kDa glycoprotein. Fusion of foot processes was observed only when the beta-amylase fraction from IMLNS patients in relapse was infused.

CONCLUSIONS

The infusion of the beta-amylase fraction containing a 100-kDa glycoprotein from IMLNS patients in relapse induced proteinuria and effacement of foot processes in the rat. This protein may play a role in the pathogenesis of IMLNS.

Immune responses in advanced colorectal cancer following repeated intradermal vaccination with the anti-CEA murine monoclonal antibody, PR1A3: results of a phase I study

BACKGROUND AND AIMS

The aim was to determine the toxicity, clinical and immune responses to the murine monoclonal anti-carcinoembryonic antigen (CEA) antibody, PR1A3, in patients with advanced colorectal cancer.

MATERIALS AND METHODS

Fifteen patients with advanced colorectal cancer received either 0.5-, 1.0- or 5.0-mg doses of PR1A3 mixed with 10% w/v Alum adjuvant (Superfos Biosector, Denmark) intradermally at 4-week intervals for 3 months. Patient serum was assessed for anti-idiotypic (Ab2), anti-anti-idiotypic (Ab3) and human anti-mouse antibody (HAMA) reactivity. Peripheral blood mononuclear cell (PBMC) proliferation with phytohaemagglutinin (PHA), CEA and PR1A3, stimulated IL-2, IL-4 and IFN-gamma levels and PR1A3-stimulated IL-2 receptor expression during immunotherapy were determined. Comparisons were made with 16 age-matched controls without malignant disease.

RESULTS

Hyperimmune sera from 12 of the 15 patients showed Ab2 reactivity with no detectable Ab3 responses. Strong HAMA reactivity was recorded in 7 of the 15 cases with no adverse clinical effect. Delayed-type hypersensitivity (DTH) responses developed in 12 of the 15 patients. Pre-treatment PBMC proliferation with PHA was subnormal in each patient compared with controls, becoming normal (or supranormal) in all patients during immunisation (P<0.001). PBMC proliferation with CEA and PR1A3 increased during immunotherapy (P<0.001) along with stimulated production of IL-2, IFN-gamma and IL-2 receptor expression. Progressive disease was observed in 14 of the 15 patients with minimal toxicity.

CONCLUSION

PR1A3 generated limited idiotypic responses but robust DTH reactivity in most patients. In vitro PBMC proliferation with mitogens and recall antigens is greatly increased during the course of immunisation, with a shift in stimulated cytokine profile.