Serum immunoglobulins in the nephrotic syndrome. A possible cause of minimal-change nephrotic syndrome

The autoimmune architecture of childhood idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome, the most common glomerular disorder in children, has long been considered an immune-mediated disease based on the efficacy of glucocorticoids at inducing remission. Nevertheless, the immune processes leading to podocytopathy have largely remained elusive. The success of B-cell depletion with rituximab, descriptions of B-cell dysregulation during active disease, and the most recent discovery of autoantibodies targeting the major podocyte antigen nephrin point to an autoimmune humoral etiology for idiopathic nephrotic syndrome. Investigations of the immune factors involved in idiopathic nephrotic syndrome pathogenesis have uncovered common features with other autoimmune disorders that will aid in prognostication and in guiding the expansion of our glucocorticoid-sparing therapeutic arsenal. In this review, we discuss the emerging autoimmune architecture of idiopathic nephrotic syndrome, with a specific focus on pediatric steroid-sensitive disease, including the podocyte-reactive B-cell response that causes anti-podocyte antibodies, the predisposing genetic factors that shape the podocyte-reactive immune landscape, and the immune triggers driving active disease.

Changes in Serum Immunoglobulin Levels Play as Predictors of Treatment Response and Prognosis in Pediatric Idiopathic Nephrotic Syndrome During the Remission Phase

BACKGROUND

Nephrotic syndrome is an immune-mediated renal disorder characterized by T-cell and B-cell dysfunctions with changes in immunoglobulin (Ig) levels and the IgG:IgM ratio. Therefore, this study aimed to determine whether the serum level of Igs can be considered as an index to predict the response to treatment and the prognosis of idiopathic nephrotic syndrome (INS) in children in the remission phase.

METHODS

The study population consisted of 38 children with INS in the remission phase and 38 age- and sex-matched healthy children. Blood samples were collected from participants and serum values of IgG, IgM, IgE, and IgA were measured using EISA KITS from Aptech Services. The IgG:IgM ratio was studied in the participants.

RESULTS

Patients significantly increased IgM and IgE levels compared with healthy subjects, unlike IgG and IgA values (p < 0.001-0.05). Patients with steroid-resistant nephrotic syndrome (SRNS) had a significant increase in IgM levels compared with those with steroid-sensitive nephrotic syndrome (SSNS) (p < 0.05). While, subjects with SRNS showed significant reductions in IgG and IgA values (p < 0.01). There were significant differences in the levels of IgG and IgM between steroid-sensitive patients with and without a history of relapse (p < 0.01). Furthermore, patients with steroid-independent and frequently relapsing NS showed a significant increase in IgE value compared with that of subjects with steroid-dependent and relapse (p < 0.05). The ratio of IgG/IgM was significantly reduced in patients compared with healthy individuals (p < 0.05). Other results indicated that there was a significant difference between patients with steroid-independent and steroid-dependent who had a history of relapse (p < 0.01).

CONCLUSION

Alterations in serum Ig values can be considered as predictors of treatment response and prognosis in pediatric idiopathic nephrotic syndrome during the remission phase.

Proteomic Analysis of Idiopathic Nephrotic Syndrome Triggered by Primary Podocytopathies in Adults: Regulatory Mechanisms and Diagnostic Implications

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

Nephrotic-range proteinuria: a potential risk factor for failure of tixagevimab-cilgavimab prophylaxis

BACKGROUND

Pre-exposure prophylaxis with tixagevimab-cilgavimab has been shown to reduce the incidence of SARS-CoV-2 infection in immunocompromised individuals. Individuals with nephrotic-range proteinuria can lose immunoglobulins such as tixagevimab-cilgavimab in the urine and, therefore, may derive less benefit from tixagevimab-cilgavimab. There are no published studies evaluating the association of nephrotic-range proteinuria with failure of tixagevimab-cilgavimab prophylaxis.

METHODS

We conducted a retrospective observational cohort study of all individuals at our center who received tixagevimab-cilgavimab while they had nephrotic-range proteinuria. Each individual in the nephrotic group was matched 1:3 with controls who were matched for B cell depletion therapy in addition to the total dose and date of first tixagevimab-cilgavimab administration. The primary outcome was the development of breakthrough SARS-CoV-2 infection after receiving tixagevimab-cilgavimab.

RESULTS

Sixteen patients received tixagevimab-cilgavimab between January 1st, 2022, and June 30th, 2022, at a time when they had nephrotic-range proteinuria. Proteinuria levels and serum creatinine levels were higher while serum albumin levels were lower in the nephrotic group compared to the control group. At a median follow-up of 251 days, 38% of individuals in the nephrotic group had developed breakthrough SARS-CoV-2 infections, compared to only 13% in the control group at a median follow-up of 238 days. Nephrotic-range proteinuria was associated with a higher incidence of breakthrough infection (log-rank P = 0.04).

CONCLUSIONS

Nephrotic-range proteinuria may increase the risk of failure of tixagevimab-cilgavimab pre-exposure prophylaxis. Prospective studies to validate these findings and to evaluate the optimal dosing strategy of antibody-based prophylaxis in this group of patients are needed.

High Albumin Clearance Predicts the Minimal Change Nephrotic Syndrome Relapse

Key Points

Albumin kinetics not only reflected the pathophysiology of minimal change nephrotic syndrome but was also a predictor of relapse. The high estimated 24-hour albumin clearance predicts the minimal change nephrotic syndrome relapse. The 24-hour albumin clearance can easily be calculated from only serum albumin and urinary protein excretion, which are routine laboratory measurements.

Background

Although albuminuria leakage that occurs in minimal change nephrotic syndrome (MCNS) may be related to the disease state, albumin kinetics in MCNS has never been evaluated. In this study, we investigated albumin kinetics in adult Japanese patients with MCNS by the estimated 24-hour albumin clearance (eCALB) and examined the association between eCALB and relapse.

Methods

We retrospectively identified 103 adult patients with a histological diagnosis of MCNS from four hospitals in Japan (2010–2020). The primary outcome is the first relapse in 2 years after complete remission after corticosteroid therapy. The eCALB [µ l/min] was defined as (2.71828(0.0445+0.9488×log(urinary protein) [g/24 hours])/(serum albumin [g/dl]×1440 [min/24 hours]) for women and (2.71828(-0.1522+0.9742×log(urinary protein) [g/24 hours])/(serum albumin [g/dl]×1440 [min/24 hours]) for men.

Results

Relapse was observed in 44 patients (103 kidney biopsy samples; 42.7%). The mean patient age was 41.0 years. Patients had an eGFR of 71.0 ml/min per 1.73 m2, urinary protein excretion of 6.8 g/d, serum albumin of 1.4 g/dl, and eCALB of 2.27 μ l/min. eCALB was strongly associated with hypoalbuminemia, severe proteinuria, lipid abnormalities, and coagulopathy. In the multivariable analysis, a high eCALB was significantly associated with relapse after adjusting for age, eGFR, time to complete remission, and urinary protein excretion (adjusted hazard ratio, 5.027; 95% confidence interval, 1.88 to 13.47; P = 0.001).

Conclusions

This study revealed that eCALB, which could substitute albumin kinetics, reflected the severity of MCNS, and a high eCALB was associated with recurrence.

Increased cerebrospinal fluid pressure and nephrotic syndrome: A case report and literature review

OBJECTIVE

To analyze how nephrotic syndrome (NS) correlates to increased intracranial pressure (ICP), and to present a case of an adult patient whose initial manifestation of NS was cephalalgia, with the later identification of raised ICP.

METHODS

Data were retrospectively retrieved from the patient's record, and a literature search with the keywords "nephrotic syndrome", "intracranial hypertension" and "headache" was conducted in PubMed and Embase.

RESULTS

This is a rare description of co-occurrence of NS and raised ICP in a 48-year-old man, in which ICP normalizes after NS remits. There is no known cause for the raised ICP of our patient. Ten reports (n = 13) of concomitant occurrence of increased ICP and NS were described in the literature, both in children and adults. Cerebral venous thrombosis (CVT) was the most likely underlying cause for the majority of them. For one patient, the underlying cause was meningoencephalitis. Finally, in one case, the cause is unknown, but CVT was not discarded.

CONCLUSION

The early suspicion of elevated ICP is warranted in patients with new-onset headache and NS. It is possible that NS could both directly and indirectly lead to increased ICP through yet unknown mechanisms, although this direct causal relationship cannot be currently established.

Immunosuppression Exposure and Risk of Infection-Related Acute Care Events in Patients With Glomerular Disease: An Observational Cohort Study

Rationale & Objective

Infections cause morbidity and mortality in patients with glomerular disease. The relative contributions from immunosuppression exposure and glomerular disease activity to infection risk are not well characterized. To address this unmet need, we characterized the relationship between time-varying combinations of immunosuppressant exposure and infection-related acute care events while controlling for disease activity, among individuals with glomerular disease.

Study Design

Prospective, multicenter, observational cohort study.

Setting & Participants

Adults and children with biopsy-proven minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or immunoglobulin A nephropathy/vasculitis were enrolled at 71 clinical sites in North America and Europe. A total of 2,388 Cure Glomerulonephropathy Network participants (36% aged <18 years) had at least 1 follow-up visit and were included in the analysis.

Exposures

Immunosuppression exposure modeled on a weekly basis.

Outcome

Infections leading to an emergency department visit or hospitalization.

Analytical Approach

Marginal structural models were used to estimate the effect of time-varying immunosuppression exposure on hazard of first infection-related acute care event while accounting for baseline sociodemographic and clinical factors, and time-varying disease activity.

Results

A total of 2,388 participants were followed for a median of 3.2 years (interquartile range, 1.6-4.6), and 15% experienced at least 1 infection-related emergency department visit or hospitalization. Compared to no immunosuppression exposure, steroid exposure, steroid with any other immunosuppressant, and nonsteroid immunosuppressant exposure were associated with a 2.65-fold (95% CI, 1.83-3.86), 2.68-fold (95% CI, 1.95-3.68), and 1.7-fold (95% CI, 1.29-2.24) higher risk of first infection, respectively.

Limitations

Absence of medication dosing data, lack of a control group, and potential bias in ascertainment of outcome events secondary to the coronavirus 2 pandemic.

Conclusions

Corticosteroids with or without concomitant additional immunosuppression significantly increased risk of infection leading to acute care utilization in adults and children with glomerular disease.

Antioxidant Status, Blood Constituents and Immune Response of Broiler Chickens Fed Two Types of Diets with or without Different Concentrations of Active Yeast

Simple Summary

Rations for broilers can be safely supplemented with probiotics such as active Saccharomyces cerevisiae (SC) yeast to stimulate oxidative reactions and immune response against stress and infectious agents. The current study suggested that SC yeast enhanced antioxidant capacity, growth rate, immune organ weights, immune response and the survival rate of broilers after Avian Influenza virus challenge at 38 days of age.

Abstract

Probiotics, such as active yeasts, are widely used to enhance poultry production and reduce feeding costs. This study aimed to investigate the antioxidant and immune responses of broilers to different concentrations of active Saccharomyces cerevisiae (SC) when supplemented to two types of diets. A total of 216 1-day-old Arbor Acres unsexed chicks were used in a factorial design, involving two feeds (regular- versus low-density diet) and three concentrations of SC (0%, 0.02% and 0.04%). The results revealed that the low-density diet reduced the body weight and production index of broilers. The addition of SC improved the production index more than the control diet. Total antioxidant capacity (TAC), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and eosinophils were significantly higher in response to the regular-density diet than the low-density diet; however, phagocytic activity (PA), lymphocyte and lysozyme activity (LYS) were lower. Saccharomyces cerevisiae reduced ALT, AST, malondialdehyde (MAD) and TAC more than the standard set, but improved packed cell volume (PCV), hemoglobin (Hgb), red blood cells (RBCs), lymphocytes, monocytes, heterophils, phagocytic index (PI) and the immune response to Newcastle disease virus (NDV) and avian influenza (AI). In conclusion, supplementation of a regular- or low-density diet with SC at a concentration of 0.02% or 0.04% improved the antioxidant parameters, immune status and production index of broilers against stress and infectious agents.

B-Cell Dysregulation in Idiopathic Nephrotic Syndrome: What We Know and What We Need to Discover

The therapeutic efficacy of B-cell depletion by anti-CD20 treatment in pediatric and, more recently, in adult idiopathic nephrotic syndrome patients suggests a key role of B cells in the pathogenesis of the disease. However, their exact role is still unclear. B cells are able to secrete a large variety of antibodies that can protect against infections. However, B-cell dysregulation is well-established in a variety of autoimmune diseases. In parallel with their ability to produce antibodies, pathogenic B cells display altered effector functions by expressing activating surface molecules, which can strongly modify the immune homeostasis, or by producing specific cytokines, which can directly affect either podocyte structure and functions or modulate T-cell homeostasis. Herein, we report the most relevant clinical and experimental evidences of a pathogenic role of B cells in idiopathic nephrotic syndrome. We further highlight similarities and differences between children and adults affected by non-genetic forms of the disease and discuss what needs to be investigated in order to define the exact mechanisms underlying the pathogenic role of B cells and to identify more tailored therapeutic approaches.

Analysis and Study on Epidemiological Features and Prognosis of Nephrotic Syndrome in Xinjiang and Heilongjiang

Backgrounds

The pathogenesis of nephrotic syndrome (NS) is complex, and there are differences between regions. This study attempted to collect clinicopathological data of patients diagnosed with NS in Xinjiang and Heilongjiang in the past 2 years, so as to explore the onset features of NS and treatment and prognosis of patients in the two regions.

Methods

Clinical data of 375 patients diagnosed with NS using renal biopsy in Xinjiang and Heilongjiang from March 2019 to March 2021 were collected. Clinical data of patients before treatment were collected, and the chi-square test was utilized to compare the differences in the sex distribution of two groups. The U test was utilized to compare abnormal distribution continuous data between two groups, such as age, hemoglobin, plasma albumin, proteinuria, and triglycerides. Independent sample t-test was utilized to compare normal distribution continuous data between two groups, such as serum total protein, serum creatinine, blood urea nitrogen, glomerular filtration rate, and total cholesterol. The independent sample t-test was also used to compare the immunoglobulin levels and complement levels between the two groups after treatment, including IgA, IgG, IgM, C3, and C4. Kaplan-Meier method was used to analyze and plot the cumulative curves of complete remission rate and partial remission rate.

Results

For 275 NS patients from Xinjiang, the male-to-female ratio was 0.81 : 1. For 84 patients from Heilongjiang, the male-to-female ratio was 1.05 : 1. The onset ages of patients in Xinjiang and Heilongjiang were 22-45 years old and 22-47 years old, respectively. Respectively, there were 221 cases (80.36%) and 66 cases (78.57%) of primary NS in Xinjiang and Heilongjiang. There were 54 cases (19.64%) and 18 cases (21.43%) of secondary NS in Xinjiang and Heilongjiang, respectively. There was no statistically significant difference in cause distribution between the two regions (p = 0.756). After treatment, immunoglobulin levels (IgA (p = 0.009), IgG (p = 0.002), IgM (p < 0.001)) and complement C3 (p < 0.001) and C4 (p < 0.001) levels in Xinjiang and Heilongjiang were statistically significant. 129 cases in Xinjiang (46.91%) and 55 cases in Heilongjiang (65.48%) were treated with glucocorticoid (GC) combined with immunosuppressive therapy, respectively. After receiving treatment, 67 (24.36%) of 275 patients in Xinjiang achieved complete remission, 166 (60.36%) achieved partial remission, 22 (26.19%) of 84 patients in Heilongjiang achieved complete remission, and 56 (66.67%) achieved partial remission, and there was no statistically significant difference in remission rate between the two regions (p = 0.159). Patients in Xinjiang and Heilongjiang achieved complete remission at an average of 10.34 weeks (9.98-10.70) and 9.95 weeks (9.26-10.65), respectively. There was no significant difference in complete remission rates between the two regions (p = 0.663). Patients in Xinjiang and Heilongjiang achieved partial remission at an average of 8.76 weeks (8.38-9.14) and 7.99 weeks (7.33-8.65), respectively. There was no significant difference in the partial remission rate between the two regions (p = 0.065).

Conclusion

The causes of NS in Xinjiang and Heilongjiang were similar. After treatment, there were differences in immunoglobulin levels (IgA, IgG, IgM) and complement levels (C3, C4) in the two regions. The main treatment methods used in the two regions were GC combined with immunosuppressive therapy. The prognosis of patients in the two regions was similar. The complete remission rate and partial remission rate after treatment in the two regions were similar, and the average time required to achieve complete remission and partial remission was also similar.

Natural antibody and complement activation characterize patients with idiopathic nephrotic syndrome

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

Evaluation of Immune and Vaccine Competence in Steroid-Sensitive Nephrotic Syndrome Pediatric Patients

Idiopathic nephrotic syndrome is a childhood renal disease characterized by a damage of the glomerular filtration barrier leading to an intense leakage of proteins into the urine. This severe proteinuria causes a transient but strong reduction of serum IgG. Therefore, evaluation of vaccine competence by measuring serum levels of protective antibodies can be misleading in nephrotic syndrome, especially during the active phase of disease. To overcome this issue, in parallel to measuring serum antigen-specific IgG, we quantified by ELISPOT the number of antigen-specific memory B cells induced by previous immunization with tetanus and hepatitis B virus (HBV) in 11 steroid-sensitive nephrotic syndrome (SSNS) pediatric patients at onset before any immunosuppressive treatment (mean age 5.1±0.9 years). Five age-matched children with non-immunomediated nephro-urologic disorders were also enrolled as controls (mean age 6.9±2.3 years). Low total serum IgG levels (<520 mg/dl) were found in all the analyzed SSNS patients. In parallel, median levels of anti-tetanus and anti-HBV IgG were significantly reduced compared to controls [0.05 (0.03–0.16) vs. 0.45 (0.29–3.10) IU/ml and 0.0 (0.0–0.5) vs. 30.3 (5.5–400.8) mIU/ml, respectively; p = 0.02 for both], with serum IgG titers below protective threshold in 7/11 SSNS patients for tetanus and in 9/11 SSNS patients for HBV. In contrast, all SSNS patients had a competent B-cell response, showing an amount of total IgG-secreting B cells >1,000 counts/10⁶ stimulated cells. The amount of anti-tetanus and anti-HBV IgG-secreting B cells was also comparable to that of controls (p = 0.24, p = 0.32, respectively), with a frequency of memory anti-tetanus and anti-HBV IgG secreting B cells >0.1% of total IgG secreting B cells. In conclusion, SSNS children at disease onset pre-immunosuppressive therapy showed a competent immune and vaccine response against tetanus and HBV, which can be correctly evaluated by quantification of antigen-specific memory B cells rather than by measuring serum IgG levels. This approach allows early identification of the impairment of immune and vaccine competence, which may derive from protracted use of different immunosuppressive drugs during disease course.

Association between Immunoglobulin M and Steroid Resistance in Children with Nephrotic Syndrome: A Retrospective Multicenter Study in Japan

Background

The prognosis of steroid-resistant nephrotic syndrome (SRNS) in children is poorer than steroid-sensitive cases. Diagnosis of SRNS is made after observing the response to the initial 4-week corticosteroid therapy, which might be accompanied by side effects. However, predictive indicators at initial diagnosis remain unknown. We aimed to investigate whether selectivity index (SI) and other indicators at initial diagnosis-for example, serum IgM and total serum protein-albumin ratio (TA ratio, total serum protein level over albumin level)-can predict SRNS.

Methods

A total of 80 children were enrolled from seven hospitals in Japan between January 2008 and December 2019 (mean age, 4.7 years; 65% male). Of the children enrolled, 13 (16%, M/F=5:8) had been diagnosed as steroid resistant after initial treatment with steroids. The association between serum IgM (tertile categories: low, 24-133; middle, 134-169; and high, 169.1-510 mg/dl), SI (<0.2 or ≥0.2), and TA ratio (tertile categories: low, 1.8-2.6; middle, 2.62-3.75; and high, 3.8-15.3) at initial diagnosis and steroid resistance was evaluated with logistic regression, adjusting for age and sex.

Results

Low levels of serum IgM were significantly associated with steroid resistance (adjusted odds ratio, 6.94; 95% CI, 1.12 to 43.11). TA ratio and SI were not significantly associated with steroid resistance.

Conclusions

Low levels of serum IgM at initial diagnosis might predict steroid resistance among Japanese children with idiopathic nephrotic syndrome.

Risk Factors for Poor Prognosis of Severe Infection in Children With Idiopathic Nephrotic Syndrome: A Double-Center, Retrospective Study

Background: Infection is the most common complication of Idiopathic Nephrotic Syndrome (INS) and the main cause of INS recurrence, severe infection and even leading to mortality. The purpose of this study was to investigate the risk factors of severe infection in INS children and the clinical parameters influencing prognosis. Methods: Totally 147 children with INS and concomitant infections were enrolled and classified into the severe infection group (SIG) and Non-severe infection group (Non-SIG). The clinical characteristics and auxiliary examination results were compared between the two groups, and the early-warning parameters for severe infection and risk factors for poor prognosis were evaluated. Results: There were 49 patients in the SIG, 98 patients in the Non-SIG. In the SIG, the most common severe infections disease included severe pneumonia (63.6%), severe sepsis (30.6%), septic shock (4.1%). In SIG, Gram-positive bacteria (GPB) were more common, as was respiratory syncytial virus (RSV), and the three most common strains were Pseudomonas aeruginosa, Staphylococcus aureus (SA) and Staphylococcus epidermidis. There were more steroid-resistant nephrotic syndrome and combination of steroids and immunosuppressants in SIG, compared with the Non-SIG (P = 0.000). Patients in the SIG has lower complement 3 (C3, ≤ 0.55 g/L,) and absolute lymphocyte count (ALC, ≤ 1.5 × 10⁹/L) (P = 0.004). Logistic regression analysis revealed that the independent risk factors for severe infections were the combined use of immunosuppressants [95% confidence interval (CI):1.569-463.541, P = 0.023], steroid resistance (95% CI: 4.845-2,071.880, P = 0.003), C-reactive protein (CRP) ≥8 mg/L (95% CI: 43.581-959, 935.668, P = 0.001), and infections caused by GPB (95% CI: 27.126-2,118, 452.938, P = 0.002), influenza (95% CI: 2.494-1, 932.221, P = 0.012) and RSV (95% CI: 5.011-24 963.819, P = 0.007). The patients in the SIG were classified into the survival group (N = 39) and the mortality group (N = 5). Logistic regression analysis showed that white blood cell count (WBC) >15 × 10⁹/L (95% CI: 1.046-2.844, P = 0.033) was an independent risk factor of poor prognosis for these patients. Conclusions: Resistance to steroids, combined with steroids and IS agents, and GPB infections (especially SA) are high-risk factors for severe infection in children with INS. We should monitor CRP ≥ 8 mg/L, C3 ≤ 0.55 g/L and ALC ≤ 1.5 × 10⁹/L to avoid developing severe infection. Accompanied by an increase in ANC, WBC significantly increased, suggesting a fatal infection.

First case of minimal change nephrotic syndrome resolving with antifungal therapy for isolated pleural cryptococcal infection

We report the case of a 71-year-old male with poorly controlled diabetes mellitus who presented with lower extremity edema and acute renal failure. He was diagnosed with nephrotic syndrome secondary to minimal change disease (MCD). Treatment with steroids was withheld due to concern for hyperglycemia in the context of his poorly controlled diabetes mellitus. A week after discharge, he was subsequently re-hospitalized four times within a month with pleural effusions, dyspnea, and fever. Work up revealed isolated pleural cryptococcosis, demonstrated on two separate admissions. There was neither evidence of disseminated disease nor immunocompromising condition. Immunosuppression was not initiated for the treatment of MCD in the setting of poorly controlled diabetes and active infection. After six months of treatment with fluconazole 400 mg/day, the nephrotic syndrome, renal failure, and cryptococcal pleuritis resolved. This case is the first to our knowledge of isolated pleural cryptococcosis associated with nephrotic syndrome. The patient’s course lends further support to the hypothesis that there may be causal relationship between cryptococcosis and nephrotic syndrome.

Igg Subclasses in Capd Patients

Objective

To make a comparison of serum levels of immunoglobulin G (lgG) subclasses in adult continuous ambulatory peritoneal dialysis (CAPD) patients with those in age-and sex-matched hemodialysis patients and healthy volunteers, and to analyze the contribution of removal of these proteins in peritoneal effluent to their plasma values.

Design

A cross-sectional study.

Setting

A renal unit of a university hospital.

Patients

Twenty-three CAPD patients, 21 hemodialysis patients, and 21 healthy volunteers. Peritoneal transport studies were done in 8 of the 23 CAPD patients.

Methods

IgG subclasses were measured in serum by nephelometry. For the peritoneal transport studies an ELISA method on ethylenediamine tetracetic acid plasma was used. The same method was used in seven-to ten-fold concentrated peritoneal dialysate.

Results

CAPD patients had lower IgG2 and IgG4 1evels than hemodialysis patients and healthy volunteers (p < 0.01). lgG2 values below 1.5 glL were present in 43% of the CAPD patients (p < 0.001 compared to healthy volunteers). Peritonitis incidence was not different between CAPD patients with low or normal IgG2 plasma levels. Peritoneal clearance of IgG3 was lower than that of the other subclasses. Evidence was obtained for a depressed synthesis of IgG2 and IgG4 in CAPD patients. The hypothesis that interleukin-2 may be involved in the low synthesis rate of IgG2 is discussed.

Conclusion

Low serum IgG2 and IgG4 1evels are present in stable, adult CAPD patients. These were not caused by increased peritonealloss, but by decreased synthesis.

Pediatric Immunization Practices in Nephrotic Syndrome: An Assessment of Provider and Parental Knowledge

Background: Children with nephrotic syndrome (NS) are at high risk for vaccine-preventable infections due to the immunological effects from the disease and concurrent treatment with immunosuppressive medications. Immunizations in these patients may be deferred due to their immunosuppressive treatment which may increase the risk for vaccine-preventable infections. Immunization practices in children with NS continue to vary among pediatric nephrologists. This raises the question of whether children with NS are receiving the recommended vaccinations at appropriate times. Therefore, it is critical to understand the practices and patient education provided by physicians to patients on the topic of vaccinations. Methods: After informed consent, parents/guardians of 153 pediatric patients (<18 years old) diagnosed with NS from 2005 to 2018 and 50 pediatric nephrologists from 11 participating centers completed anonymous surveys to evaluate immunization practices among pediatric nephrologists, assess the vaccine education provided to families of children with NS, assess the parental knowledge of immunization recommendations, and assess predictors of polysaccharide pneumococcal vaccine adherence. The Advisory Committee on Immunization Practices (ACIP) Immunization 2019 Guideline for those with altered immunocompetence was used to determine accuracy of vaccine knowledge and practices. Results: Forty-four percent of providers self-reported adherence to the ACIP guidelines for inactive vaccines and 22% to the guidelines for live vaccines. Thirty-two percent of parents/guardians reported knowledge that aligned with the ACIP guidelines for inactive vaccines and 1% for live vaccines. Subjects residing in the Midwest and provider recommendations for vaccines were positive predictors of vaccine adherence (p < 0.001 and p 0.02, respectively). Conclusions: Vaccine recommendation by medical providers is paramount in vaccine adherence among pediatric patients with NS. This study identifies potential educational opportunities for medical subspecialty providers and family caregivers about immunization recommendations for immunosuppressed patients.

Circulating follicular T helper cells are possibly associated with low levels of serum immunoglobulin G due to impaired immunoglobulin class-switch recombination of B cells in children with primary nephrotic syndrome

Clinically, most patients with primary nephrotic syndrome (PNS) have low serum IgG levels, which is an important factor in infection and in PNS relapse.To some extent, the mechanisms involved remain largely unknown. Here, we aimed to investigate the pathogenesis of the decreased IgG levels in PNS. Peripheral blood was collected from patients with PNS and closely age- and sex-matched healthy individuals. The frequency, phenotype and molecular function of different circulating B cell and T follicular helper cell (TFH) subsets were examined by flow cytometry. The function of the CD40/CD40 L interaction in immunoglobulin class-switch recombination (CSR) was evaluated by assessing the induction of activation-induced deaminase (AID) expression with CD40 L stimulation. We revealed an increase in the levels of circulating total plasmablasts, plasma cells and mature-naive B cells and a decrease in the levels of germinal centre-like B cells and CD19⁺IgG⁺ B cells in PNS. In addition, although the expression of CD86 on the surface of B cells and the expression of the inducible costimulator (ICOS) on the surface of TFH cells both were increased, the expression of CD40 L on the surface of TFH cells was decreased. Moreover, upon stimulation with CD40 L in vitro, the mRNA expression of AID in peripheral blood mononuclear cells (PBMCs) was decreased in patients with PNS compared with that in healthy controls. Our results indicate that the immunoglobulin CSR of B cells was partly dysfunctional and provide insights into the potential involvement of impaired TFH cell-dependent B cell responses in the pathogenesis of low IgG levels through downregulating CD40 L expression on TFH cells in PNS.

Prolonged Impairment of Immunological Memory After Anti-CD20 Treatment in Pediatric Idiopathic Nephrotic Syndrome

Anti-CD20 therapy is effective in idiopathic nephrotic syndrome (INS). However, transient or sustained hypogammaglobulinemia predisposing to an increased risk of infectious diseases can follow treatment in some patients. We analyzed the long-term effects of anti-CD20 therapy on immunological memory in 27 frequently-relapsing/steroid-dependent INS pediatric patients after more than 4 years from the first and at least 2 years from the last anti-CD20 infusion. Twenty-one INS children, never treated with anti-CD20 and under an intense oral immunosuppression with prednisone, mycophenolate mofetil, and calcineurin inhibitors were also included as control group. Levels of circulating B-cell subpopulations, total serum immunoglobulins and IgG and memory B cells directed against hepatitis B virus (HBV) and tetanus were determined and correlated with clinical characteristics. Nine patients never relapsed after more than 2 years from the last anti-CD20 administration (5 after the first, 3 after the second, and 1 after the fifth infusion). At last follow-up, most patients showed a complete recovery and normalization of total (27/27), transitional (27/27), and mature-naïve B cells (25/27). However, a sustained and significant reduction of total memory (20/27) and switched memory (21/27) B cells was found in most patients. 11/27 patients showed hypogammaglobulinemia at last follow-up and, among these, four presented with a severe hypogammaglobulinemia (IgG < 160 mg/dl). In contrast, no patient in the control group developed a severe hypogammaglobulinemia. Age at the time of first anti-CD20 administration was positively associated with IgG levels at last follow-up (p = 0.008); accordingly, younger patients had an increased risk of hypogammaglobulinemia (p = 0.006). Furthermore, severe hypogammaglobulinemia and delayed switched memory B-cell reconstitution were more frequent in non-relapsing patients. Reduced IgG levels against HBV and tetanus were observed at baseline and further declined at last follow-up. Antigen-specific memory B-cells were induced by re-immunization, but specific IgG titers remained low. In conclusion, anti-CD20 therapy can be disease-modifying in some INS patients. However, a prolonged impairment of immunological memory occurs frequently, independently from the number of anti-CD20 infusions, particularly in younger patients. Re-immunization may be necessary in these patients.

Immunoglobulin E and G Levels in Predicting Minimal Change Disease before Renal Biopsy

Purpose

The diagnosis of minimal change disease in adults relies mainly on renal biopsy, but this procedure is not without complications. Despite the advancements in technique of percutaneous renal biopsy, biopsy-related complications still occur. Bleeding is one of the major complications, which may lead to hemodynamic instability and, sometimes, even death. Thus, we developed a model to predict MCD for high-risk patients unsuitable for renal biopsy.

Methods

We enrolled 142 patients with nephrotic syndrome who received renal biopsy between October 2007 and April 2011 at one tertiary medical center in this study. Demographic, clinical, and prebiopsy laboratory variables were retrospectively recorded and analyzed.

Results

The overall prevalence of MCD was 26.8%. Age, hemoglobin levels, 24-hour urine protein, immunoglobulin (Ig) G, and IgE differed significantly between the MCD and non-MCD groups. Logistic regression analysis showed a significant increase in the risk of developing MCD as the number of Ig risk factors, namely, IgG < 450 mg/dl and IgE > 110 mg/dl, increased. Having both risk factors significantly increased the chances of receiving a diagnosis of MCD (by 31.84-fold, P =.007) compared with having neither. Combining the aforementioned clinical model and the 2 Ig risk factors was the best in predicting the diagnosis of MCD, with the area under a receiver-operating characteristic curve of 0.91.

Conclusions

Combining clinical model and this 2 Ig risk factors provides physicians simple and valuable clinical markers to diagnose MCD.

Infections in hospitalized lupus nephritis patients: characteristics, risk factors, and outcomes

Background There are limited studies documenting infection epidemiology in lupus nephritis (LN) patients. We aimed to study infection incidences and risk characteristics and ascertain possible predictors of infective outcomes in a multiethnic Asian population. Methods This retrospective study from 2006 to 2012 included newly diagnosed LN patients. We collected admissions, immunosuppression, and infection data until end-stage renal failure, death, last follow-up, or the year 2015. The infection incidence rates were evaluated and a generalized linear latent and mixed models (GLLAMM) analysis was carried out to evaluate potential predictors of infection. Results Our cohort of 101 patients consisted of mainly Chinese (75.2%), females (78.2%), and a median age of 38 years (IQR 26-49). The median time of follow-up was 72.8 months (IQR 49.5-94.0). Six out of 14 patient deaths were infection related. Seventy-eight out of 200 admissions, with a total of 102 episodes of infection, occurred in 46 patients. The incidence of infection rates leading to admissions was 10.3 per 100 person-years and the incidence of infection episodes rates was 17.6 per 100 person-years. Cytomegalovirus (CMV) was the most common organism identified. Univariate GLLAMM analysis showed Malay compared to Chinese ethnicity (HR 2.833 (95% CI 1.088-7.373)), use of oral cyclophosphamide (HR 6.618 (95% CI 1.015-43.154)) and rituximab (HR 3.967 (95% CI 1.157-13.603)) as predictors of infection-related admissions. Malay ethnicity and rituximab remained significant in the multivariate GLLAMM analysis. Conclusions Our study highlights substantial infection incidences in patients with LN and its contribution to deaths.

Distribution of glomerular diseases in Taiwan: preliminary report of National Renal Biopsy Registry-publication on behalf of Taiwan Society of Nephrology

Background

Despite the development of biomarkers and noninvasive imaging tools, biopsy remains the only method for correctly diagnosing patients with unexplained hematuria, proteinuria and renal failure. Renal biopsy has been performed for several decades in Taiwan; however, a national data registry is still lacking until 2013.

Methods

The Renal Biopsy Registry Committee was established within the Taiwan Society of Nephrology in January 2013. A biopsy registry format, including basic demographic data, baseline clinical features, laboratory data, and clinical and pathological diagnosis was developed. Approval from the local institutional review board was obtained in each participating medical center.

Results

From January 2014 to September 2016, 1445 renal biopsies were identified from 17 medical centers. 53.8% cases were reported in men. After excluding renal transplantation, renal biopsies were commonly performed in patients with primary glomerulonephritis (48.1%), secondary glomerulonephritis (36.2%), followed by tubulointerstitial diseases (12.3%) and vascular nephropathy (3.4%). Among primary glomerulonephritis, IgA nephropathy (26.0%), focal segmental glomerulosclerosis (21.6%), and membranous nephropathy (20.6%) were most frequently diagnosed. Diabetic nephropathy (22.4%) and lupus nephritis (21.8%) were the most common among secondary glomerulonephritis. Patients with minimal change disease and membranous nephropathy had heavier proteinuria than those with focal segmental glomerulosclerosis and IgA nephropathy (P < 0.001). Patients with minimal change disease had higher serum IgM and IgE levels. The most common cause of nephrotic syndrome in primary glomerular disease was membranous nephropathy (28.8%), followed by minimal change disease (28.2%). IgA nephropathy was the leading cause of chronic nephritic syndrome, acute nephritic syndrome, and persistent hematuria. The incidence of primary glomerulonephritis was approximately 2.19 in 100,000/year.

Conclusions

This is the first report of the National Renal Biopsy Registry in Taiwan. IgA nephropathy is the most common primary glomerulonephritis, while membranous nephropathy is the most common cause of nephrotic syndrome. Primary glomerulonephritis distribution in Taiwan is slightly different from that in other Asian countries.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0810-4) contains supplementary material, which is available to authorized users.

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.

A unified pathogenesis for kidney diseases, including genetic diseases and cancers, by the protein-homeostasis-system hypothesis

Every cell of an organism is separated and protected by a cell membrane. It is proposed that harmony between intercellular communication and the health of an organism is controlled by a system, designated the protein-homeostasis-system (PHS). Kidneys consist of a variety of types of renal cells, each with its own characteristic cell-receptor interactions and producing characteristic proteins. A functional union of these renal cells can be determined by various renal function tests, and harmonious intercellular communication is essential for the healthy state of the host. Injury to a kind of renal cells can impair renal function and induce an imbalance in total body health. Every acute or chronic renal disease has unknown etiologic substances that are responsible for renal cell injury at the molecular level. The immune/repair system of the host should control the etiologic substances acting against renal cells; if this system fails, the disease progresses to end stage renal disease. Each renal disease has its characteristic pathologic lesions where immune cells and immune proteins, such as immunoglobulins and complements, are infiltrated. These immune cells and immune proteins may control the etiologic substances involved in renal pathologic lesions. Also, genetic renal diseases and cancers may originate from a protein deficiency or malfunctioning protein under the PHS. A unified pathogenesis for renal diseases, including acute glomerulonephritis, idiopathic nephrotic syndrome, immunoglobulin A nephropathy, genetic renal diseases such as Alport syndrome, and malignancies such as Wilms tumor and renal cell carcinoma, is proposed using the PHS hypothesis.

The effect of systemic corticosteroids on the innate and adaptive immune system in children with steroid responsive nephrotic syndrome

The severity and duration of immunosuppression caused by corticosteroids (CSs) usage have not been extensively studied. We aimed to investigate the effects of CSs on the various compartments of immune system in relation to timing of initiation and persistence of therapy. Pediatric patients with idiopathic nephrotic syndrome (NS) treated with 2 mg/kg/day prednisolone and healthy control (HC) were enrolled. Blood samples were drawn for immunologic analyses at baseline and at the first and second weeks and first, second, and third months of CS therapy in addition to first and second weeks and first, second, and third months of discontinuation. Fourteen patients (M/F, 7/7) between 1 and 8 years old were evaluated. Untreated NS exhibited high absolute lymphocyte count (ALC)(p = 0.010), absolute CD3(+) T cells (p = 0.020) and absolute CD8(+) T cells (p = 0.006) compared to HC. Suppression in ALC was observed and nadir value was noted at first month of therapy compared to baseline (p = 0.002). The CD4(+) (p = 0.036) and CD8(+) T cell (p = 0.013) counts decreased significantly at the first week of treatment compared to baseline. While baseline B cell counts was indifferent from HC, gradually increased in 2 weeks of CS initiation and decreased during the treatment with a statistical significance compared to HC (p = 0.010). However, after cessation of CS, B cell counts continued to decline and found to be significantly different than baseline at first week (p = 0.008) and at third month (p = 0.040).

CONCLUSION

Apart from baseline lymphocyte subset changing observed in untreated NS patients, our data implies that T cells were suppressed very early in the CS treatment. Interestingly, depressed B cell counts were detected later but persisted even after CS cessation. Due to early decrease in T cells, it would be beneficial to assume the patients as immunosuppressed at the very beginning of CS treatment to avoid infections.

WHAT IS KNOWN

• Corticosteroids (CSs) are widely used for a variety of diseases including nephrotic syndrome, which is related with complex immune disturbance including T and B cells dysfunctions. • CSs induce neutrophilic leukocytosis concomitant with lymphopenia and eosinopenia leading to immunosupression. What is New: • T cell subsets and proliferation are susceptible to CSs more than B cells; however, the reversibility is faster with dose reduction in CS. • The change of B cells and B cell subtypes (CD27 (+) memory) shows prolonged effect of CSs on B cells which may alter antibody production even after 3 months of CSs cessation.

Fatal Strongyloides Hyperinfection Syndrome in an Immunocompromised Patient

BACKGROUND

Currently, it is normal to screen for Strongyloides as part of the workup in pre-transplant patients who have eosinophilia. Given the high mortality rates in Strongyloides hyperinfection, this article illustrates the need to screen all patients with eosinophilia who will be started on immunosuppression.

CASE REPORT

We present here an interesting case of a 76-year-old man with membranous glomerulopathy who developed a severe Strongyloides hyperinfection that required an ICU stay and ultimately led to his death a few weeks after initiation of cyclophosphamide and steroids.

CONCLUSIONS

We recommend that a detailed workup to detect or rule out this parasitic infection be conducted prior to the initiation of immunosuppression in any patient with eosinophilia.

Serum immunoglobulin E and interleukin-13 levels in children with idiopathic nephrotic syndrome

Serum IgE and IL-13 levels were estimated in 40 idiopathic nephrotic syndrome and 16 controls. There were 15 first episode nephrotic syndrome (FENS), 15 infrequent relapsing nephrotic syndrome (IRNS) and 10 patients belonged to frequent relapsing nephrotic syndrome (FRNS). Serum IgE and IL-13 levels were significantly increased in active nephrotic syndrome and its sub-groups as compared to controls and remission (p < 0.001). IgE levels did not differ significantly among different subgroups, while Il-13 was significantly higher in FRNS in comparison with FENS (p = 0.041). Both IgE and IL-13 levels were comparable in nephrotic patients with and without bronchial asthma. Serum IL-13 had significant positive correlation with IgE (r = 0.605, p < 0.001). Thus, raised levels of IgE and IL-13 are found in nephrotic syndrome and could have a role in the pathogenesis of disease.

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.

Serum immunoglobulin G level in patients with lupus nephritis and the effect of treatment with corticosteroids and mycophenolate mofetil

BACKGROUND

Reduced serum IgG level is associated with increased risk of infection. We investigated the circulating IgG level and its determining factors in active lupus nephritis patients treated with corticosteroids and mycophenolate mofetil (MMF).

METHODS

This was a retrospective study on the longitudinal IgG profile in Class III/IV ± V lupus nephritis patients treated with prednisolone and MMF.

RESULTS

46 patients were included. At baseline, 34 (73.9%) patients (Group I) had normal or elevated IgG (1444.0 ± 600.5 mg/dL) while 12 (26.1%) (Group II) had IgG levels (567.8 ± 160.9 mg/dL) below the lower limit of normal. IgG levels at baseline, three, six and 12 months after treatment were 1215.4 ± 649.7 mg/dL, 843.9 ± 347.6 mg/dL, 914.5 ± 362.4 mg/dL and 1034.6 ± 452.5 mg/dL respectively. Treatment with prednisolone and MMF led to a significant drop in IgG after two weeks, reaching a nadir at eight weeks, followed by gradual normalization. Similar changes in IgG were observed in Group I patients but there was non-significant change in Group II within the first 24 weeks. Eighteen (39.1%) patients had low IgG by six months, and only one patient had IgG <300 mg/dL, at both three and six months. IgG level was negatively associated with proteinuria at six months (r = -0.711, p = 0.010). Five of 18 patients with low IgG had infections within the first year, while IgG levels below the lower limit of normal did not increase infection risk (relative risk 1.863; 95% confidence interval 0.466 to 6.818, p = 0.280).

CONCLUSION

Reduced IgG occurred in 26% of active lupus nephritis patients and the IgG levels are significantly influenced by the severity of proteinuria. Treatment with prednisolone and MMF does not result in clinically important suppression of IgG.

Non-O1, non-O139 Vibrio cholerae sepsis in a patient with nephrotic syndrome

Non-O1, non-O139 Vibrio cholerae is an encapsulated bacterium, ubiquitous in the marine environment and generally considered to be non-pathogenic. However, it is known to cause diarrheal illness, wound infection, and bacteremia in immunocompromised hosts. Here we have describe non-O1, non-O139 V. cholerae sepsis in a patient with nephrotic syndrome following exposure to sea-water. Interestingly, the exposure occurred remotely 4 months prior to the onset of nephrotic syndrome. The occurrence of florid sepsis after a prolonged interval from the time of exposure is peculiar and raises the possibility of an association between occult Vibrio sepsis and nephrotic syndrome.

Differential diagnosis of glomerular disease: a systematic and inclusive approach

BACKGROUND

Glomerular disease is a complex and evolving topic. In evaluating a specific case it is not unusual for the clinician to ask: 'Am I missing something? Should I biopsy? When? Should I treat first, then biopsy?' This work, which is both evidence and experience based, is intended to address each of these concerns and many other issues relevant to the differential diagnosis of glomerular disease.

SUMMARY

The central approach is the use of diagnostic algorithms that are based on quantitative measures routinely obtained early in the course of the diagnostic evaluation. The algorithms are designed to be easy to navigate, systematic, and inclusive. Also provided is a detailed and prioritized list of recommended diagnostic testing, and the rationale for each test.

KEY MESSAGE

This work is intended to facilitate accurate diagnosis in the individual patient presenting with evidence of glomerular disease.

Astragalus in the prevention of upper respiratory tract infection in children with nephrotic syndrome: evidence-based clinical practice

Aims. To explore whether Astragalus or its formulations could prevent upper respiratory infection in children with nephrotic syndrome and how best to use it. Methods. We transformed a common clinical question in practice to an answerable question according to the PICO principle. Databases, including the Cochrane Library (Issue 5, 2012), PUBMED (1966-2012.8), CBM (1978-2012.8), VIP (1989-2012.8), and CNKI (1979-2012.8), were searched to identify Cochrane systematic reviews and clinical trials. Then, the quality of and recommendations from the clinical evidence were evaluated using the GRADEpro software. Results. The search yielded 537 papers. Only two studies with high validity were included for synthesis calculations. The results showed that Astragalus granules could effectively reduce URTI in children with nephrotic syndrome compared with prednisone treatment alone (23.9% versus 42.9%; RR = 0.56 and 95% CI = 0.33-0.93). The dose of Astragalus granules was 2.25 gram (equivalent to 15 gram crude Astragalus) twice per day, at least for 3-6 months. The level of evidence quality was low, but we still recommended the evidence to the patient according to GRADEpro with the opinion of the expert. Followup showed the incidence of URTI in this child decreased significantly. Conclusions. Astragalus granules may reduce the incidence of URTI in children with nephrotic syndrome.

Antibody status in children with steroid-sensitive nephrotic syndrome

PURPOSE

The pathophysiology of hypogammaglobulinemia in nephrotic syndrome (NS) remains unknown. We evaluated the differences in the distribution of anti-bacterial antibodies and anti-viral antibodies, and those of immune antibodies and natural antibodies in steroid-sensitive NS.

MATERIALS AND METHODS

We examined the antibody status of 18 children who had routine vaccinations. The levels of immnunoglobulin G (IgG), the IgG subclasses, and the antibodies induced by vaccinations such as diphtheria-pertussis-tetanus and measles-mumpsrubella were analyzed in children with steroid-sensitive NS.

RESULTS

There was a positive correlation between the albumin and IgG values (r = 0.6, p < 0.01), and the four IgG subclasses were all evenly depressed in the nephrotic children during the acute stage of the disease. The antibodies induced by bacterial antigens were depressed and the seropositivity of anti-viral antibodies tended to be lower than those of age-matched control children during the acute stage. The depressed immune antibody status recovered rapidly in the remission stage of NS, despite corticosteroid treatment.

CONCLUSIONS

IgG levels correlated positively with albumin levels, and all antibodies, including immune and natural antibodies, were depressed in the acute stage of NS. Our results suggest that hypogammaglobulinaemia in NS may be associated with intravascular homeostasis of oncotic pressure.

New insights into the pathophysiology of idiopathic nephrotic syndrome

Corticoresistant idiopathic nephrotic syndrome (INS) is a glomerulopathy of unknown etiology whose original aspect is its recurrence after kidney transplantation in 30 to 50% of patients with end-stage renal disease. This suggests the involvement of circulating factors that would alter the glomerular filtration barrier, but whose nature remains elusive. Although a T cell immune origin has been suggested, the actual role of these cells in INS recurrence is still unclear. Here we present an 8-year-old patient with corticoresistant INS who developed a recurrence of her initial disease after kidney transplantation. Rituximab therapy was proposed 11 months after transplantation; although no immediate effect was induced, a slow but persistent decrease in proteinuria began a few months after Rituximab infusions despite cessation of plasma exchanges and steroid therapy. The pathophysiology of INS and the putative mechanisms of action of Rituximab are discussed.

Serum immunoglobulin G, M and IgG:IgM ratio as predictors for outcome of childhood nephrotic syndrome

BACKGROUND

Nephrotic syndrome is an immune mediated disorder of the kidney associated with T cell dysfunction and secondary disturbance of B cell with changes in levels of immunoglobulin and IgG:IgM ratio. These changes in immunoglobulin levels can be used as a proxy marker to understand the clinical variety and prognosis of nephrotic syndrome.

METHODS

We studied 43 children with nephrotic syndrome during January 2003 to January 2005 in the Pediatric Nephrology Unit, Department of Pediatrics, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. Blood samples were collected from the 43 patients, and serum levels of IgG, IgM and IgG:IgM were measured by liquid phase immunoprecipitation assay. Another 20 healthy children attending the laboratory for blood grouping and hepatitis B screening test were enrolled as controls.

RESULTS

In the 43 children with nephrotic syndrome, 24 had steroid sensitive nephrotic syndrome (SSNS) and 19 steroid resistant nephrotic syndrome (SRNS). Compared with healthy children, the IgG level was low, IgM level was high, and IgG:IgM ratio was low (P<0.05). The serum IgG level and IgG:IgM ratio were significantly lower in children with SRNS and in children with frequent relapse (FRNS) combined with steroid dependent nephrotic syndrome (SDNS) than in those with infrequent relapse nephrotic syndrome (IFRNS) (P<0.05, respectively).

CONCLUSIONS

Management of different nephrotic syndromes is based on the levels of immunoglobulins along with clinical and biochemical parameters. The decrease of IgG level as a predictive marker for unfavorable prognosis of nephrotic syndrome in children needs further evaluation in larger scale studies.

Serum immunoglobulins and risk of infection: how low can you go?

OBJECTIVES

To determine the relationship between the levels of serum immunoglobulin (Ig) levels and risk of infection. The following 2 main questions are addressed: (1) At what level do reduced serum concentrations of the different Ig species (focusing on IgA, IgG, and IgM) significantly increase the risk of infection above background and (2) For how long can Ig depletion be tolerated before an increased risk of infection becomes apparent.

METHODS

Information was gathered from a search of PubMed and relevant congress abstracts up to and including November 2007.

RESULTS

Sustained, very low levels of IgA, IgG, or IgM, as occur in primary immunodeficiency syndromes, are associated with significantly increased risks of infections, primarily respiratory tract infections of bacterial origin. Patients with IgG levels <100 mg/dL or IgM levels <20 mg/dL for prolonged periods have an increased risk of recurrent and sometimes life-threatening infectious episodes. Generally, IgA deficiency appears better tolerated. Replenishment of IgG in patients with hypogammaglobulinemia reduces the infection risk to background if IgG levels are maintained at approximately 500 mg/dL, although higher levels may be necessary in the presence of certain comorbidities. Transient depletion of IgG and/or IgM (or, less commonly, IgA) can occur in some patients following the administration of certain drugs, including anticonvulsants, corticosteroids, and rituximab. Available evidence suggests that such changes are not generally associated with an increased risk of infections.

CONCLUSIONS

While prolonged, very low levels of IgG and/or IgM are associated with a heightened risk of infections, transient or less severe immunodeficiency appears to be tolerated in most subjects.

Adult nephrotic syndrome: non-specific strategies for treatment

Irrespective of aetiology, the nephrotic syndrome presents a range of potentially serious complications. These include thrombo-embolism, infection and hyperlipidaemia. Despite the prevalence of the nephrotic state among renal patients, there has been little prospective analysis of the therapeutic approach to these potentially life-threatening events even though their pathogenesis has been examined in some detail. Most of these complications are more prevalent once the albumin concentration falls below 20 g/L and it is recognized that restoration of serum albumin significantly diminishes their frequency. However, this may be difficult to achieve, especially in adults. The problems of thrombo-embolism and infection are of immediate concern but, in persistent cases, the additional issues of hyperlipidaemia and loss of bone density also require consideration for therapy. Thus, in addition to specific attempts to reduce proteinuria, it is recommended that high-risk nephrotic patients receive anticoagulation, pneumococcal vaccination and lipid lowering therapy. Strategies for the preservation of bone density should also be considered, particularly in patients who receive high-dose corticosteroids. Among a range of non-specific treatments for proteinuria, angiotensin-converting enzyme inhibitors appear best in terms of efficacy and safety. Prospective trials are required to clarify the longitudinal impact of these generic strategies on the protection of the persistently nephrotic patient.

Adult minimal-change disease: clinical characteristics, treatment, and outcomes

Minimal-change disease (MCD) counts for 10 to 15% of cases of primary nephrotic syndrome in adults. Few series have examined this disease in adults. A retrospective review was performed of 95 adults who had MCD and were seen at a single referral center. Examined were presenting features, response to daily versus alternate-day steroids, response to second-line agents, relapse patterns, complications of the disease and therapy, presence of acute renal failure (ARF), and outcome data. Sixty-five patients received daily and 23 received alternate-day steroids initially. There were no differences in remissions, time to remission, relapse rate, or time to relapse between daily- and alternate-day-treated patients. More than one quarter of patients were steroid resistant. At least one relapse occurred in 73% of patients; 28% were frequently relapsing. A significant proportion of frequently relapsing patients became steroid dependent. Second-line agents were used for steroid dependence, steroid resistance, or frequent relapses. No single agent proved superior. There were more remissions with second-line agents in steroid-dependent patients compared with steroid-resistant patients, and remissions were more likely to be complete in steroid-dependent patients. ARF occurred in 24 patients; they tended to be older and hypertensive with lower serum albumin and more proteinuria than those without ARF. At follow up, patients with an episode of ARF had higher serum creatinine than those without ARF. Four patients progressed to ESRD. These patients were less likely to have responded to steroids and more likely to have FSGS on repeat renal biopsy. In this referral MCD population, response to daily and alternate-day steroids is similar. Second-line agents give greater response in patients who are steroid dependent. ARF occurs in a significant number of adult MCD patients and may leave residual renal dysfunction. Few patients progress to ESRD.

Minimal change disease: a review

Minimal change disease (MCD) is a histopathological lesion in the kidney that is most commonly associated with nephrotic syndrome. The majority of the cases are idiopathic. Pathogenesis is not well understood, although T-cell-related mechanisms are implicated. Massive proteinuria leads to hypoalbuminemia, salt retention, disorder of hemostasis, hyperlipidemia and increased susceptibility to infections. Renal biopsy remains the gold standard for diagnosis. MCD is highly responsive to corticosteroids. Other immunosuppressive agents such as cyclophosphamide, cyclosporin, azathioprine and mycophenolate mofetil have been used to treat cases which are resistant to steroids.

Immunoglobulin G has a role for systemic protein modulation in vivo: a new concept of protein homeostasis

The constant level of various proteins including albumin and cellular components in intravascular pool in vivo is strictly controlled by an unknown homeostatic mechanism, although there are fluctuations seen in pathologic conditions. Because the majority of the IgG in the serum is regarded as self-reactive natural autoantibodies, IgG may have a role to react with all proteins in vivo. It is hypothesized that like an immune system, a homeostatic mechanism for the protein pool also has a sensitive role to identify and memorize the extent and repertoire of both normal and pathogenic proteins on an individual basis, and IgG may be one of the major players in performing these functions. This hypothesis may explain the unresolved clinical observations as followed: (1) the marked increased IgG levels observed in self-limiting diseases presumed to come from immunological insults such as acute poststreptococcal glomerulonephritis and Kikuchi-Fujimoto disease, (2) an immediate reduction of all protein levels except immunoglobulins after intravenous immunoglobulin (IVIG) treatment in Kawasaki disease, (3) a unified explanation for the variety of immunomodulating effects exerted by IVIG, (4) the IgG-enzyme complexes observed in benign conditions such as macroamylasemia and hyperphosphatasemia, and (5) the marked decreased IgG level, which is correlated with the albumin level in minimal change nephrotic syndrome. IgG may be a 'watch-dog' for the disturbances of protein homeostasis in vivo. IgG may control the pathogenic proteins that appeared in disordered states, and it may help prevent the loss of proteins in case of nephrotic syndrome.

Changes of lymphocyte populations in pediatric steroid-sensitive nephrotic syndrome are more pronounced in remission than in relapse

BACKGROUND/AIM

Although clinical and immunological findings in steroid-sensitive nephrotic syndrome (SSNS) favor an immunopathogenesis, many issues remain unsolved. Comprehensive studies analyzing cellular and humoral immunity in SSNS are scarce, and few studies addressed the effect of steroids on immunological factors.

METHODS

We therefore performed a cross-sectional study of T and B lymphocyte populations in 89 children during the different stages of the disease and related the findings to parameters of humoral immunity and treatment with steroids.

RESULTS

In untreated relapse, an increase in the proportion of activated CD3+ lymphocytes with a concomitant reduction of CD19+ B cells was noted compared to healthy controls. Conversely, patients with steroid dependency, relapsing on alternate-day steroids, showed a decline of the absolute numbers as well as proportion of CD4+ lymphocytes but a relative increase in CD19+ B cells, compared to healthy controls. Also untreated remission was characterized by an absolute and relative decrease in CD4+ lymphocytes compared to healthy controls which was accompanied by a significant increase in the proportion of CD8+ and also activated CD3+ lymphocytes. Steroid-induced remission resulted in suppression of absolute and relative CD4+, while absolute and relative B cells were upregulated in this group compared to untreated remission.

SUMMARY AND CONCLUSION

Alterations of lymphocyte populations in SSNS are not limited to relapse but seem to be more pronounced in remission and show a different profile with steroid treatment. Changes of lymphocyte populations do not only affect T but also B lymphocytes, which may be of relevance in the pathogenesis of this disorder.

Atopy, serum IgE, and interleukin-13 in steroid-responsive nephrotic syndrome

Earlier studies have demonstrated a strong association of steroid-responsive nephrotic syndrome (SRNS), atopy, and elevated serum IgE levels. Interleukin (IL-13) gene expression is significantly increased in children with SRNS in relapse. As interferon (IFN)-gamma, IL-13, and IL-4 have regulatory effects on IgE synthesis, we examined the relationship between intracellular cytokine production and serum IgE levels in children with SRNS, in order to further define the reported association with atopy. The median serum IgE levels in nephrotic patients in relapse with (492 U/ml) or without atopy (561 U/ml) were significantly higher than those in remission (221 U/ml, P<0.002 or 90 U/ml, P<0.001, respectively) and non-atopic controls (177 U/ml) (P<0.001). The percentage of CD3+ IL-13-producing cells was significantly higher in nephrotic children in relapse, and correlated with the serum IgE levels during the active phase of the disease (r=0.90, P<0.001). These data suggest that the elevated serum IgE levels during relapses of SRNS were the result of upregulation of IL-13. This probably reflects some common immune activation following various stimuli, rather than a direct association with atopy.

Childhood nephrotic syndrome in relapse is associated with down-regulation of monocyte CD14 expression and lipopolysaccharide-induced tumour necrosis factor-alpha production

Interleukin-13 (IL-13) is a known modulator of monocyte function, down-regulating monocyte surface markers such as CD14 and proinflammatory cytokines. We have shown previously that lymphocyte IL-13 gene expression was up-regulated during relapses in children with steroid-responsive nephrotic syndrome (SRNS). In this study, we examined the monocyte mRNA expression and lipopolysaccharide (LPS)-stimulated intracellular production of tumour necrosis factor-alpha (TNF-alpha) and IL-8 in children with SRNS during relapse and remission. Additionally, we investigated CD14 mRNA levels, CD14 surface expression and its soluble component (sCD14) in serum. Our results showed that the percentages of TNF-alpha positive monocytes following LPS stimulation were significantly lower in nephrotic children in relapse (64.4 +/- 13.7%) compared to remission (81.6 +/- 9.0%, P < 0.005). This was associated with down-regulation of CD14 mRNA, as well as both membrane and sCD14 in patients with nephrotic relapse (82.9 +/- 10.1% and 1.23 +/- 0.30 micro g/ml, respectively) compared to remission (93.9 +/- 3.2% and 1.77 +/- 0.82 micro g/ml, respectively) (P < 0.003). Although we demonstrated a decrease in LPS-stimulated intracellular production of TNF-alpha in monocytes from patients with nephrotic relapse, we were unable to show a concomitant decrease in mRNA expression during relapses. This could be explained by down-regulation of gene expression at the translational rather than transcriptional level. In conclusion, it is conceivable that up-regulation of T-cell IL-13 production in children with active nephrotic relapse was associated with suppression of monocyte CD14 expression, down-regulating pro-inflammatory cytokine production, and could account for the increased susceptibility to bacterial sepsis seen in nephrotic children in active relapse.

Successful treatment of necrotizing fasciitis associated with diabetic nephropathy

A 50-year-old woman with a 15-year history of type 2 diabetes mellitus was admitted to our hospital due to high fever and a skin lesion with severe pain, swelling and a sensation of heat in the right thigh. Laboratory examination showed elevated C-reactive protein (CRP), thrombocytopenia, nephrotic syndrome and renal dysfunction. Her blood glucose level had been well controlled. Streptococcus agalactiae was detected in both the skin lesion and blood culture, and pathological examination revealed neutrophil infiltration in the fascia and muscle layer. The patient was diagnosed with necrotizing fasciitis, septic shock and disseminated intravascular coagulation. A combination therapy of antibiotics and surgical debridement resulted in the improvement of symptoms as supported by laboratory findings, and the skin lesion also showed improvement. Although group A streptococcus is well known to be implicated in the pathogenesis of necrotizing fasciitis, only S. agalactiae, belonging to group B streptococcus, was isolated from the tissue and blood cultures in this case. Although this organism is not virulent and rarely causes a necrotizing fasciitis, both the superficial fascial layer and underlying muscle were affected in this case. There have been only a few reports of necrotizing fasciitis due to S. agalactiae in patients with diabetes mellitus. Although the blood glucose level was well controlled in our patient, this disease might be caused by other factors, including diminished sense of touch and pain, abnormality of microcirculation and hypogammaglobulinemia due to nephrotic syndrome.