Minimal Change Disease

Hyperuricemia is a risk factor for the progression to end-stage renal disease in minimal change disease

BACKGROUND

Minimal change disease (MCD) is one of the most common causes of nephrotic syndrome worldwide. Hyperuricemia increases the end-stage renal disease (ESRD) risk in glomerulonephritis. In this study, we aimed to determine the effect of high serum uric acid levels on the progression to ESRD in MCD.

METHODS

A total of 800 patients diagnosed with MCD by kidney biopsy were retrospectively analyzed. We determined the relationship of hyperuricemia with the progression to ESRD in MCD using the Cox proportional hazard model and Kaplan-Meier survival analysis. The primary outcome was defined as the initiation of dialysis or kidney transplantation.

RESULTS

A total of 42 patients (5.3%) progressed to ESRD during the follow-up period. In the restricted cubic spline curve, serum uric acid levels exhibited a positive correlation with ESRD progression in patients with MCD. In the fully adjusted model, the risk of MCD progression increased by 29% for every 1 mg/dL increase in the baseline serum uric acid level (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.09-1.54; p = 0.004). Falling into the high uric acid group (serum uric acid level > 7 mg/dL in men and > 6 mg/dL in women) was also a risk factor for progression of MCD to ESRD (HR, 3.40; 95% CI, 1.59-7.31; p < 0.001).

CONCLUSION

Our study shows that hyperuricemia is an independent risk factor for the progression to ESRD in patients with MCD.

Biomarkers in pediatric glomerulonephritis and nephrotic syndrome

Glomerular diseases are often chronic or recurring and thus associated with a tremendous physical, psychological, and economic burden. Their etiologies are often unknown, and their pathogeneses are frequently poorly understood. The diagnoses and management of these diseases are therefore based on clinical features, traditional laboratory markers, and, often, kidney pathology. However, the clinical presentation can be highly variable, the kidney pathology may not establish a definitive diagnosis, and the therapeutic responses and resulting clinical outcomes are often unpredictable. To try to address these challenges, significant research efforts have been made over the last decade to identify potential biomarkers that can help clinicians optimize the diagnosis and prognosis at clinical presentation, as well as help predict long-term outcomes. Unfortunately, these efforts have to date only identified a single biomarker for glomerular disease that has been fully validated and developed for widespread clinical use (anti-PLA2R antibodies to diagnose membranous nephropathy). In this manuscript, we review the definitions and development of biomarkers, as well as the current knowledge on both historical and novel candidate biomarkers of glomerular disease, with an emphasis on those associated with idiopathic nephrotic syndrome.

The important roles and molecular mechanisms of annexin A2 autoantibody in children with nephrotic syndrome

BACKGROUND

In recent years, B-cell dysfunction has been found to play an important role in the pathogenesis of primary nephrotic syndrome (PNS). B cells play a pathogenic role by secreting antibodies against their target antigens after transforming into plasma cells. Therefore, this study aimed to screen the autoantibodies that cause PNS and explore their pathogenic mechanisms.

METHODS

Western blotting and mass spectrometry were employed to screen and identify autoantibodies against podocytes in children with PNS. Both in vivo and in vitro experiments were used to study the pathogenic mechanism of PNS. The results were confirmed in a large multicenter clinical study in children.

RESULTS

Annexin A2 autoantibody was highly expressed in children with PNS with a pathological type of minimal change disease (MCD) or focal segmental glomerulosclerosis without genetic factors. The mouse model showed that anti-Annexin A2 antibody could induce proteinuria in vivo. Mechanistically, the effect of Annexin A2 antibody on the Rho signaling pathway was realized through promoting the phosphorylation of Annexin A2 at Tyr24 on podocytes by reducing its binding to PTP1B, which led to the cytoskeletal rearrangement and damage of podocytes, eventually causing proteinuria and PNS.

CONCLUSIONS

Annexin A2 autoantibody may be responsible for some cases of PNS with MCD/FSGS in children.

Urinary and plasma proteomics to discover biomarkers for diagnosing between diabetic nephropathy and minimal change nephrotic syndrome or membranous nephropathy

The choice of treatment for primary nephrotic syndrome depends on the pathologic type of the disorder. Renal biopsy is necessary for a definitive diagnosis, but it is burdensome for the patients, and can be avoided if tests could be performed using urine or plasma. In this study, we analyzed 100 urinary proteins, 141 plasma proteins, and 57 urine/plasma ratios in cases of diabetic nephropathy (DN; n = 11), minimal change nephrotic syndrome (MCNS; n = 14), and membranous nephropathy (MN; n = 23). We found that the combination of urinary retinol-binding protein 4 and SH3 domain-binding glutamic acid-rich-like protein 3 could distinguish between MCNS and DN, with an area under the curve (AUC) of 0.9740. On the other hand, a selectivity index (SI) based on serotransferrin and immunoglobulin G, which is often used in clinical practice, distinguished them with an AUC of 0.9091. Similarly, the combination of urinary afamin and complement C3 urine/plasma ratio could distinguish between MN and DN with an AUC of 0.9842, while SI distinguished them with an AUC of 0.8538. Evidently, the candidates identified in this study were superior to the SI method. Thus, the aim was to test these biomarkers for accurate diagnosis and to greatly reduce the burden on patients.

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Renal biopsy is necessary for a definitive diagnosis of primary nephrotic syndrome.

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Renal biopsy is a heavy burden for patients, and a less burdensome test is desired.

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We discovered at least 6 diagnostic biomarkers using urinary and plasma proteomics.

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Combination allowed to judge the disease more accurately than selectivity index.

Minimal change disease soon after Pfizer-BioNTech COVID-19 vaccination

We report on the onset of minimal change disease (MCD) presenting with anasarca after a second dose of the messenger RNA (mRNA)-based Pfizer-BioNTech vaccine against coronavirus disease 2019 (COVID-19). A 75-year-old previously healthy male was admitted with rapidly progressive anasarca and proteinuria of 7.7 g/day following the second dose. A kidney biopsy revealed MCD with nephrotic syndrome. He was treated with intravenous methylprednisolone followed by prednisolone, leading to complete remission after 35 days in the hospital. Since definite causality between the vaccine and MCD remains unclear, awareness of this potential adverse effect of mRNA vaccines is important to determine its true incidence and frequency.

A case report of congenital nephrotic syndrome caused by new mutations of NPHS1

Congenital nephrotic syndrome (CNS) is a rare autosomal recessive disorder that occurs in the first 0 to 3 months of life. The course of CNS is progressive, often leading to end-stage renal disease within 2 to 3 years. Most patients with CNS are resistant to glucocorticoids and immunosuppressive drugs. We report a girl aged 1 month and 20 days who was admitted to hospital with a history of abdominal distension and palpebral edema. She was diagnosed with CNS and administered a glucocorticoid (methylprednisolone) for 2 years. Targeted high-throughput next-generation sequencing showed mutations in the NPHS1 gene. She had a favorable outcome after 2 years of treatment. She has remained in complete remission for the last 6 months. From a clinical point of view, the outcome of CNS may be associated with end-stage renal disease or even death. Appropriate pharmacotherapy is beneficial to maintain a normal function and integrity of the glomerular barrier. An aggressive treatment plan is required to save the life of patients with CNS, even if a heterozygous mutation is detected by genetic analysis.

Clinical Characteristics and Outcomes of Adults with Nephrotic Syndrome Due to Minimal Change Disease

PURPOSE

Minimal change disease (MCD) is considered a relatively benign glomerulopathy, as it rarely progresses to end-stage kidney disease. The aim of this study was to describe the characteristics and outcomes of adults with MCD and identify potential risk factors for relapse.

PATIENTS & METHODS

We retrospectively studied a cohort of adults with biopsy-proven MCD in terms of clinical features and treatment outcomes. Baseline characteristics and outcomes were recorded and predictors of relapse were analyzed using logistic regression multivariate analysis.

RESULTS

59 patients with adult-onset primary MCD with nephrotic syndrome were included. Mean serum creatinine at diagnosis was 0.8 mg/dL (±2.5) and estimated GFR (eGFR) was 87 mL/min/1.73 m² (±29.5). Mean serum albumin was 2.5 g/dL (±0.8) and 24 h proteinuria 6.8 g (±3.7). Microscopic hematuria was detected in 35 (58.5%) patients. 42 patients received prednisone alone, six patients received prednisone plus cyclophosphamide, five patients received prednisone plus cyclosporine, one patient received prednisone plus rituximab and five patients did not receive immunosuppression at all since they achieved spontaneous remission. During a mean follow up time of 34.7(22.1) months, 46.1% of patients experienced at least one episode of relapse. The mean age of patients who did not experience a relapse was significantly higher than that of patients who relapsed while relapsers had a significantly longer duration of 24 h proteinuria prior to biopsy compared to non-relapsers. Overall, 10% of patients experienced acute kidney injury while the mean eGFR at the end was 82 mL/min/1.73 m² (±29.1) and one patient ended up in chronic dialysis. Overall, the proportion of non-relapsers, who experienced acute kidney injury (17%) was significantly higher than the one recorded among relapsers (0%).

CONCLUSION

In this series of patients, almost 46% of adult-onset nephrotic MCD patients experienced a relapse, although their renal progression was rare. Younger onset age was an independent risk factor for relapse in adult-onset MCD patients.

Association of initial prednisolone dose with remission, relapse, and infectious complications in adult-onset minimal change disease

BACKGROUND

A dose of 0.5-1 mg/kg/day of prednisolone (PSL) is administered for the initial treatment of minimal change disease (MCD). However, little is known about the optimal PSL dose for the initial treatment of MCD.

METHODS

We conducted a retrospective multicenter cohort study of treatment-naive adult patients with MCD diagnosed by renal biopsy from 1981 to 2015 in whom PSL monotherapy was performed as the initial treatment. The exposure of interest was an initial median PSL dose of < 0.63 mg/kg/day (Group L) compared to ≥ 0.63 mg/kg/day (Group H). Cumulative remission and relapse after remission were compared between these groups using Cox regression adjusted for baseline characteristics.

RESULTS

Ninety-one patients met the inclusion criteria. During a median follow-up of 2.98 years, 87 (95.6%) patients achieved complete remission, and 47.1% relapsed after remission. There was no significant difference in the remission rate between the groups at 4 weeks of follow-up (66.7 vs. 82.6%). The median time to remission in Group L was comparable to that in Group H (17.0 vs. 14.0 days). A multivariable Cox hazard model revealed that the initial PSL dose was not a significant predictor of remission. The cumulative steroid doses at 6 months, 1 year, and 2 years after treatment initiation were significantly lower in Group L than in Group H.

CONCLUSION

The initial PSL dose was not associated with time to remission, remission rate, time to relapse, or relapse rate. Therefore, a low initial steroid dose may be sufficient to achieve remission.

New-onset Nephrotic Syndrome after Janssen COVID-19 Vaccination: a Case Report and Literature Review

Various coronavirus disease 2019 (COVID-19) vaccines are being developed, which show practical preventive effects. Here, we report a 51-year-old healthy man with nephrotic syndrome secondary to minimal change disease (MCD) after Ad26.COV.2 (Janssen) vaccination. He had no comorbid disease and received Ad26.COV.2 on April 13, 2021. Seven days after vaccination, he developed edema and foamy urine. Edema rapidly aggravated with decreased urine volume. He was admitted to the hospital 28 days after vaccination, and his body weight increased by 21 kg after vaccination. His serum creatinine level was 1.54 mg/dL, and 24-h urinary protein excretion was 8.6 g/day. Kidney biopsy revealed no abnormality in the glomeruli and interstitium of the cortex and medulla under the light microscope. Electron microscopy revealed diffuse effacement of the podocyte foot processes, thus, he was diagnosed with MCD. High-dose steroid therapy was applied, and his kidney function improved three days after steroid therapy. Three weeks after steroid use, his serum creatinine decreased to 0.95 mg/dL, and spot urine protein-to-creatine decreased to 0.2 g/g. This case highlights the risk of new-onset nephrotic syndrome secondary to MCD after vectored COVID-19 vaccination. Although the pathogenesis is uncertain, clinicians need to be careful about adverse renal effects of COVID-19 vaccines.

Minimal change disease and subacute interstitial nephritis in association with Edwardsiella tarda gastroenteritis following oyster consumption

Edwardsiella tarda (E. tarda) is a gram-negative, facultatively anaerobic bacillus that is associated with gastroenteritis and a host of other extra-intestinal manifestations in humans. However, its impact on the kidneys is unclear. Most literature that has explored this association involves fish, marine life in which E. tarda inhabits. We report a rare case of a 72-year-old female who presented with an acute kidney injury (AKI) associated with newfound minimal change disease, subacute interstitial nephritis, and a severe E. tarda infection. Her clinical course resolved with antibiotics and glucocorticoids.

The disturbance and clinical significance of B cell and circulating follicular helper T cell subsets in children with primary nephrotic syndrome

The immunopathogenesis of primary nephrotic syndrome is unclear. Here, we examined the frequency, subsets and molecular function of circulating B cells and follicular helper T cells by flow cytometry and explored the correlation between certain subsets and clinical disease indices in new-onset patients, relapsing patients and healthy controls. We found an increase in the proportions of CD86⁺ activated cells and CD19⁺CD138⁺ plasma cells in the patients at onset and patients in relapse. However, the increased percentage of CD27⁺ memory cells was observed in only the relapse group. Furthermore, the ICOS MFI was elevated in TFH cells and their three subsets in new-onset patients, whereas the expression of OX40 was increased in TFH cells, TFH17 cells and TFH2 cells in the relapse group. Additionally, the increased frequency of CD19⁺CD138⁺ plasma cells was positively associated with urea nitrogen in the new-onset groups. Notably, the positive correlation between CD86⁺ activated B cells and CD19⁺CD138⁺ plasma cells was obtained in only the new-onset group and HC group; however, the increased CD27⁺ memory cell percentage was positively correlated with 24-h urinary protein in only the relapse group. Our results indicate that CD19⁺CD138⁺ plasma cells may be a key factor for the onset of PNS, whereas CD27⁺ memory cells may play a more important role in the relapse of this disease. Furthermore, the functions of TFH cells are also diverse because the expression of vital molecules changes during the different disease phases.

CD73 Overexpression in Podocytes: A Novel Marker of Podocyte Injury in Human Kidney Disease

The CD73 pathway is an important anti-inflammatory mechanism in various disease settings. Observations in mouse models suggested that CD73 might have a protective role in kidney damage; however, no direct evidence of its role in human kidney disease has been described to date. Here, we hypothesized that podocyte injury in human kidney diseases alters CD73 expression that may facilitate the diagnosis of podocytopathies. We assessed the expression of CD73 and one of its functionally important targets, the C-C chemokine receptor type 2 (CCR2), in podocytes from kidney biopsies of 39 patients with podocytopathy (including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous glomerulonephritis (MGN) and amyloidosis) and a control group. Podocyte CD73 expression in each of the disease groups was significantly increased in comparison to controls (p < 0.001–p < 0.0001). Moreover, there was a marked negative correlation between CD73 and CCR2 expression, as confirmed by immunohistochemistry and immunofluorescence (Pearson r = −0.5068, p = 0.0031; Pearson r = −0.4705, p = 0.0313, respectively), thus suggesting a protective role of CD73 in kidney injury. Finally, we identify CD73 as a novel potential diagnostic marker of human podocytopathies, particularly of MCD that has been notorious for the lack of pathological features recognizable by light microscopy and immunohistochemistry.

A randomised controlled unblinded multicentre non-inferiority trial with activated vitamin D and prednisolone treatment in patients with minimal change nephropathy (ADAPTinMCN)

BACKGROUND

Minimal change nephropathy (MCN) is a common cause of nephrotic syndrome in both adults and children. International guidelines recommend treatment with prednisolone 1 mg/kg/day to adults. This dose is derived from an empirically established dose in children, although children generally attain remission faster and relapse more rapidly than adults. Prednisolone is associated with multiple and serious adverse events. Activated vitamin D has been shown to reduce albuminuria in other glomerular renal diseases with a minimum of adverse events. This study tests the hypothesis that a new treatment regimen in MCN combining reduced dose prednisolone and active vitamin D is as efficient in inducing remission and has fewer and less severe adverse events than standard prednisolone. Furthermore, we aim to establish models allowing for more personalized medicine based on assessment of the individual's prednisolone metabolism.

METHODS

A randomised controlled multicentre non-inferior unblinded trial including 96 adult, incident patients with biopsy-proven MCN, albuminuria > 3 g/day, and an estimated glomerular filtration rate (eGFR) > 30 ml/min from renal departments in Denmark. Patients are randomised to standard prednisolone (1 mg/kg/day) or reduced prednisolone (0.5 mg/kg/day) and alfacalcidol (0.5 μg/day). The primary outcome is the rate of remissions after 16 weeks and the time from diagnosis to remission. The study will include a saliva test to characterise prednisolone pharmacokinetics and compare them to genetic variations in specific liver enzymes responsible for prednisolone metabolism.

DISCUSSION

Reducing the prednisolone dose is expected to reduce the number of severe adverse events. This study will examine if reduced prednisolone dose with active vitamin D but without additional immunosuppression is feasible in the treatment of MCN and will reduce the number of adverse events. The findings can potentially change current guidelines for treatment of MCN in adults. Additional outcomes on inter-individual pharmacokinetic and metabolic variations may allow for a more personalised treatment strategy.

TRIAL REGISTRATION

EudraCT 2017-001206-16, ClinicalTrials.gov NCT03210688 . Registered on June 3, 2017.

Long-term health-related quality of life outcomes of adults with pediatric onset of frequently relapsing or steroid-dependent nephrotic syndrome

BACKGROUND

Long-term psychosocial outcomes and health-related quality of life (HRQOL) in adults with pediatric onset of frequently relapsing or steroid-dependent idiopathic nephrotic syndrome (FRNS or SDNS) remain to be determined.

METHODS

In this prospective cohort study, 59 adults with pediatric onset of FRNS/SDNS and persistent active glomerular disease in adulthood completed the GEDEPAC-2 questionnaire exploring 11 well-being domains. Data were compared to the French general population (FGP) with standardized incidence ratio ([SIR]; adjusted for period, age, gender). Regression models were performed to identify predictive factors of psychosocial well-being.

RESULTS

In 82% of cases, the questionnaire was completed while the participants (n = 59; 47 men; median age = 32 years; median number of relapses = 13) were in complete remission (under specific therapy in 76% of cases). Participants had higher educational degree than in the FGP (SIR = 6.3; p < 0.01) and more frequently a managerial occupation (SIR = 3.1; p < 0.01). Social integration was acceptable with regard to marital status and experience of sexual intercourse, but experiences of discrimination were far more frequent (SIR = 12.5; p < 0.01). The SF-12 mental component summary (MCS) score was altered (Z-score = - 0.6; p < 0.01) and mean multidimensional fatigue inventory (MFI-20) global fatigue score appeared high (12). Transfer from pediatric to adult healthcare was followed by a period of discontinued care for 33% of participants. Multivariate analysis revealed a close relationship between MFI-20, physical health, and MCS.

CONCLUSIONS

This study shows that pediatric onset FRNS and SDNS may have a long-term negative impact on mental HRQOL and highlights the impact of fatigue, which is often not adequately considered in routine care.

Extended infusion of rituximab combined with steroids is effective in inducing remission and reducing relapse in adult minimal change disease

Background

Minimal change disease is a common cause of nephrotic syndrome in adults. Higher relapse rate put patients at risk of steroids toxicity due to long-term exposure. Rituximab has been suggested to maintain long time remission and withdraw steroids and other immunosuppressants with fewer adverse events. However, optimal dose and dosing interval have not been explored.

Methods

Twenty-five patients were enrolled from 2017-10 to 2020-03 in Nanfang Hospital in China. Clinical and biological data were extracted from medical records and laboratory databases. Therapy composed of 375mg/m² rituximab once three weeks for 3 dose and corticosteroid was applied. Complete remission was defined as reduction of proteinuria to 0.3g/d. Remission rate, relapse rate, steroids used before and after rituximab therapy and adverse effects were documented at a mean time of 14.71 months.

Results

Twenty-two patients achieved complete remission for an average of 3.26 months and only 3 patients experienced one relapse respectively during the follow-up period. The mean remission maintenance time was 11.6 months, and was 5 months after steroids withdrawal. Steroids dose at last follow-up was 6.09mg/d, which was significantly reduced compared to 28.15mg/d before rituximab. Relapse rate before and after rituximab was 1.43 and 0.1, respectively. Only four minor adverse events were recorded.

Conclusions

Therapy consisted of 375mg/m² rituximab once three weeks for 3 dose combined with corticosteroid is effective in inducing remission in adult patients with minimal change disease. Both of the relapse rate and dose of steroids used are significantly decreased with fewer side effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02437-4.

Incidence and Relapse of Idiopathic Nephrotic Syndrome: Meta-analysis

CONTEXT

Idiopathic nephrotic syndrome (INS) in children is a disease with considerable morbidity, yet the incidence and risk for relapse have not been systematically reviewed.

OBJECTIVE

To estimate the overall pooled weighted incidence and risk for relapse of INS in children.

DATA SOURCES

Medline and Embase (until December 2020).

STUDY SELECTION

All studies reporting incidence (per 100 000 children per year) and/or risk for relapse (the proportion of patients who experience ≥1 relapse) of INS in children (age: <18 years) were eligible.

DATA EXTRACTION

After quality assessment, data were extracted: study (design, localization, and sample size) and patient (age, sex, steroid response, and ethnicity) characteristics, incidence, and risk for relapse.

RESULTS

After screening, 73 studies were included for analysis (27 incidence, 54 relapse). The overall pooled weighted estimate and corresponding prediction interval (PI) of the incidence was 2.92 (95% PI: 0.00-6.51) per 100 000 children per year. Higher incidences were found in non-Western countries (P < .001). Incidence tended to be lower in white children, but this was not significant. The overall pooled weighted estimate of the risk for relapse was 71.9% (95% PI: 38.8-95.5). Between 1945 and 2011, incidence did not change (P = .39), yet the risk for relapse decreased significantly (P = .024), from 87.4% to 66.2%.

LIMITATIONS

There was no full-text availability (n = 33), considerable heterogeneity, and limited studies from Africa, Latin America, and Asia.

CONCLUSIONS

INS has a low incidence with ethnic variation but high risk for relapse. Although corticosteroids have significantly reduced the risk for relapse, it remains unacceptably high, underscoring the need for alternative treatment strategies.

Starting off on the right foot: A 22-year-old woman with leg swelling

A previously healthy 22-year-old woman was in the second trimester of her first pregnancy when she developed new lower extremity edema. Her pregnancy course had been unremarkable, and she was receiving routine obstetric care from her family physician. One week prior to admission she developed progressive swelling in her legs.

The immune cell landscape of peripheral blood mononuclear cells from PNS patients

Existing research suggests that the human immune system and immune cells are involved in the pathogenesis of nephrotic syndrome, but there is still a lack of direct evidence. This study tried to analyze the profiling of immune cells in the peripheral blood of steroid-sensitive nephrotic syndrome (SSNS) patients and steroid-resistant nephrotic syndrome (SRNS) patients before and after standard steroid treatment to clarify the immunological mechanism of nephrotic syndrome patients. The number and proportion of CD4 + T cells in patients with nephrotic syndrome remained unchanged. However, there is an imbalance of Th1 and Th2 and an excessive increase of Th17 cells. The number of CD8 + T cells and the number of effector CD8 + T cells in them increased significantly, but only in SSNS, the number of activated CD8 + T cells increased, and the number of activated T_reg cells decreased significantly. Nephrotic syndrome patients also have B cell disorder, and it is more prominent in SSNS patients. Compared with the normal control, only the number of B cells and plasmablast in SSNS patients increased significantly (Z = − 2.20, P = 0.028). This study also observed that transitional B cells decreased in both SSNS and SRNS patients, but SSNS patients' decrease was lower than in SRNS patients. Compared with normal controls, monocytes in patients with nephrotic syndrome decreased significantly. The main reason was that Non-classical Monocyte decreased, while Classical Monocyte increased slightly. The total number of NK cells did not change, but the internal cell subgroups' composition occurred. Changes, realized as CD56hi NK cells increased, CD56low NK cells decreased; and the above trend is more evident in SSNS patients. Patients with nephrotic syndrome have immune disorders, including T cells, B cells, Monocytes, and NK cells. It can be confirmed that immune factors are involved in the pathogenesis of the nephrotic syndrome.

Circulating plasmablasts and high level of BAFF are hallmarks of minimal change nephrotic syndrome in adults

BACKGROUND

The recent success achieved with the use of B cell-depleting agents in some patients with minimal change nephrotic syndrome (MCNS) suggests an unexpected role for B lymphocytes in the pathogenesis of this immune-mediated glomerular disease. Nevertheless, no extensive B-cell phenotyping analysis has ever been performed in untreated adult patients soon after MCNS diagnosis.

METHODS

We investigated the distribution of the different B-cell subpopulations in 22 untreated adult patients with biopsy-proven MCNS [MCNS relapse (MCNS-Rel)]. We compared these data with those for 24 healthy controls, 13 MCNS patients in remission (with no specific treatment) and 19 patients with idiopathic membranous nephropathy (IMN).

RESULTS

Patients with MCNS-Rel or IMN had higher proteinuria and lower serum albumin and gammaglobulin levels (P < 0.0001 for all comparisons) than MCNS patients in remission. Plasmablasts were the only B-cell subsets present at significantly higher levels in MCNS-Rel patients than in the patients of the other three groups (P < 0.05 for all comparisons). The lower albumin levels and higher proteinuria levels were positively correlated with the percentage of circulating plasmablasts (Spearman test's ρ = -0.54, P = 0.01 and ρ = 0.65, P = 0.002, respectively). Similarly, the increase of immunoglobulin M (IgM) and the decrease of IgG levels were significantly associated with the percentage of plasmablasts in MCNS-Rel patients (Spearman's ρ = 0.36, P = 0.01 and Spearman's ρ = -0.60, P = 0.01, respectively). Increased production of interleukin (IL)-21, IL-6 and B-cell activating factor (BAFF) in the serum of MCNS-Rel patients was found significantly correlated with the percentage of plasmablasts (ρ = 0.72, P = 0.0002, ρ = 0.49, P = 0.04 and ρ = 0.62, P = 0.009, respectively).

CONCLUSIONS

An increase in the proportion of circulating plasmablasts seems to be a hallmark of untreated MCNS in adult patients. Further studies are required to more precisely determine the phenotype and functions of these cells.

The Continuing Need for Electron Microscopy in Examination of Medical Renal Biopsies: Examples in Practice

Background

For the better part of the past 6 decades, transmission electron microscopy (EM), together with routine light microscopy and immunofluorescence and/or immunohistochemistry (IHC), has been an essential component of the diagnostic workup of medical renal biopsies, particularly native renal biopsies, with increasing frequency in renal allograft biopsies as well. Studies performed prior to the year 2000 have indeed shown that a substantial fraction of renal biopsies cannot be accurately diagnosed without EM. Still, EM remains costly and labor-intensive, and with increasing pressure to reduce healthcare costs, some centers are de-emphasizing diagnostic EM. This trend has been coupled with advances in IHC and other methods in renal biopsy diagnosis over the past 2-3 decades.

Summary

Nonetheless, it has been our experience that the diagnostic value of EM in the comprehensive evaluation of renal biopsies remains similar to what it was 20-30 years ago. In this review, we provide several key examples from our practice where EM was essential in making the correct renal biopsy diagnosis, ranging from relatively common glomerular lesions to rare diseases.

Key Messages

EM remains an important component of the diagnostic evaluation of medical renal biopsies. Failure to perform EM in certain cases will result in an incorrect diagnosis, with possible clinical consequences. We strongly recommend that tissue for EM be taken and stored in an appropriate fixative and ultrastructural studies be performed for all native renal biopsies, as well as appropriate renal allograft biopsies as recommended by the Banff consortium.

Gene Expression as a Guide to the Development of Novel Therapies in Primary Glomerular Diseases

Despite improvements in understanding the pathogenic mechanisms of primary glomerular diseases, therapy still remains nonspecific. We sought to identify novel therapies targeting kidney-intrinsic injury of distinct primary glomerulonephritides through computational systems biology approaches. We defined the unique transcriptional landscape within kidneys from patients with focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), immunoglobulin A nephropathy (IgAN), membranous nephropathy (MN) and thin basement membrane nephropathy (TBMN). Differentially expressed genes were functionally annotated with enrichment analysis, and distinct biological processes and pathways implicated in each primary glomerular disease were uncovered. Finally, we identified novel drugs and small-molecule compounds that may reverse each glomerulonephritis phenotype, suggesting they should be further tested as precise therapy in primary glomerular diseases.

Role of Arachidonic Acid and Its Metabolites in the Biological and Clinical Manifestations of Idiopathic Nephrotic Syndrome

Studies concerning the role of arachidonic acid (AA) and its metabolites in kidney disease are scarce, and this applies in particular to idiopathic nephrotic syndrome (INS). INS is one of the most frequent glomerular diseases in childhood; it is characterized by T-lymphocyte dysfunction, alterations of pro- and anti-coagulant factor levels, and increased platelet count and aggregation, leading to thrombophilia. AA and its metabolites are involved in several biological processes. Herein, we describe the main fields where they may play a significant role, particularly as it pertains to their effects on the kidney and the mechanisms underlying INS. AA and its metabolites influence cell membrane fluidity and permeability, modulate platelet activity and coagulation, regulate lymphocyte activity and inflammation, preserve the permeability of the glomerular barrier, influence podocyte physiology, and play a role in renal fibrosis. We also provide suggestions regarding dietary measures that are able to prevent an imbalance between arachidonic acid and its parental compound linoleic acid, in order to counteract the inflammatory state which characterizes numerous kidney diseases. On this basis, studies of AA in kidney disease appear as an important field to explore, with possible relevant results at the biological, dietary, and pharmacological level, in the final perspective for AA to modulate INS clinical manifestations.

Association between diuretic administration before diagnosis and incidence of acute kidney injury in patients with minimal change disease: A single-center observational study

We examined the association between diuretic administration before the diagnosis of minimal change disease and the incidence of acute kidney injury. Moreover, we examined whether the use of diuretics affected the time to complete remission in adults with such disease.The present study was a single-center, retrospective, observational cohort study. We included 107 patients with biopsy-proven minimal change disease who were treated at a tertiary referral center in Japan between January 1, 2000 and March 31, 2019. All biopsy specimens were examined by a board-certified renal pathologist. The patients were considered to have minimal change disease when the kidney biopsy specimen had no glomerular lesions or only mild focal mesangial prominence (not exceeding 3 or 4 cells per segment) by light microscopy and/or foot process effacement by electron microscopy. Logistic regression and Kaplan-Meier curve analyses were performed, comparing the data of patients who received diuretics or not.The median age was 47 (28-66) years, 52% of patients were women, and the median proteinuria dosage was 8.3 (5.3-11.2) g/d. When minimal change disease was diagnosed, 27% of patients were taking diuretics. Within 30 days after the diagnosis, acute kidney injury occurred in 27% of patients. On multivariable logistic regression analysis, the use of diuretics was significantly associated with a higher risk of acute kidney injury. The use of diuretics was also associated with a longer time to complete remission.Diuretic administration can be associated with an elevated acute kidney injury risk and longer remission time in adult patients with newly diagnosed minimal change disease.

Apheresis in Adult With Refractory Idiopathic Nephrotic Syndrome on Native Kidneys

Background

Apheresis is the gold standard for idiopathic nephrotic syndrome (INS) relapse after transplantation, but it remains unknown whether such treatment is useful for adults with refractory INS on native kidneys.

Methods

This retrospective study included patients older than 16 years with biopsy-proven refractory (persistent nephrotic syndrome on corticosteroids plus at least 1 immunosuppressive drug) INS treated by apheresis and followed for at least 3 months.

Results

Between September 1997 and January 2020, 21 patients (focal segmental glomerulosclerosis: 12, minimal change nephrotic syndrome: 9, men: 67%, median age: 34 years) were identified. At last follow-up (12 months), 7 of 21 patients were in complete or partial remission. Remission was associated with older age (51 vs. 30 years, P = 0.05), lower proteinuria (3.9 vs. 7.3 g/d, P = 0.03), and lower estimated glomerular filtration rate (eGFR) (28.0 vs. 48.5 ml/min per 1.73 m², P = 0.05) at apheresis. The need for dialysis before apheresis (odds ratio [OR] 22.0 [1.00–524], P = 0.026), age ≥50 years (OR: 22.6 [1.00–524], P = 0.006), a marked (>4.5 g/d) decrease in proteinuria (OR: 9.17 [1.15–73.2], P = 0.041), and a short (<12 months) time between diagnosis and apheresis (OR: 10.8 [1–117], P = 0.043) were significantly associated with remission. Three of 7 patients in remission who were initially on dialysis became dialysis-free; by contrast, none of the 14 patients without remission was initially on dialysis, but 5 of 14 had become dialysis-dependent (P = 0.01).

Conclusion

Apheresis may result in remission in adult patients with refractory INS, particularly in those at risk of renal failure, with limited sensitivity to medical treatments, if apheresis is initiated within a year of diagnosis.

Roles of microRNAs in renal disorders related to primary podocyte dysfunction

Through the regulation of gene expression, microRNAs (miRNAs) are capable of modulating vital biological processes, such as proliferation, differentiation, and apoptosis. Several mechanisms control the function of miRNAs, including translational inhibition and targeted miRNA degradation. Through utilizing high-throughput screening methods, such as small RNA sequencing and microarray, alterations in miRNA expression of kidneys have recently been observed both in rodent models and humans throughout the development of chronic kidney disease (CKD) and acute kidney injury (AKI). The levels of miRNAs in urine supernatant, sediment, and exosomal fraction could predict novel biomarker candidates in different diseases of kidneys, including IgA nephropathy, lupus nephritis, and diabetic nephropathy. The therapeutic potential of administrating anti-miRNAs and miRNAs has also been reported recently. The present study is aimed at reviewing the state-of-the-art research with regards to miRNAs involved in renal disorders related to primary podocyte dysfunction by laying particular emphasis on Focal Segmental Glomerulosclerosis (FSGS), Minimal Change Disease (MCD) and Membranous Nephropathy (MN).

Spontaneous Bacterial Peritonitis in an Adult Patient with Minimal Change Disease

Patient: Male, 60-year-old

Final Diagnosis: Peritonitis

Symptoms: Abdominal pain • edema of lower extermities

Medication: —

Clinical Procedure: —

Specialty: Nephrology

Minimal Change Disease Following the Pfizer-BioNTech COVID-19 Vaccine

We report on the development of minimal change disease (MCD) with nephrotic syndrome and acute kidney injury (AKI), shortly after first injection of the BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). A 50-year-old previously healthy man was admitted to our hospital following the appearance of peripheral edema. Ten days earlier, he had received the first injection of the vaccine. Four days after injection, he developed lower leg edema, which rapidly progressed to anasarca. On admission, serum creatinine was 2.31 mg/dL and 24-hour urinary protein excretion was 6.9 grams. As kidney function continued to decline over the next days, empirical treatment was initiated with prednisone 80 mg/d. A kidney biopsy was performed and the findings were consistent with MCD. Ten days later, kidney function began to improve, gradually returning to normal. The clinical triad of MCD, nephrotic syndrome, and AKI has been previously described under a variety of circumstances, but not following the Pfizer-BioNTech COVID-19 vaccine. The association between the vaccination and MCD is at this time temporal and by exclusion, and by no means firmly established. We await further reports of similar cases to evaluate the true incidence of this possible vaccine side effect.

Parallel disease activity of Behçet's disease with renal and entero involvements: a case report

Background

Behçet’s disease (BD) is a systemic inflammatory vasculitis with both autoimmune and autoinflammatory properties. Renal involvement in BD and its spontaneous remission have been rare. We herein describe a case of parallel disease activity of BD with entero and renal involvements, followed by a spontaneous remission without corticosteroid treatment.

Case presentation

A 54-year-old woman who had a 4-year history of BD, maintained with colchicine treatment, suffered abdominal pain, hemorrhagic stool and diarrhea. Physical examination revealed strong tenderness in the entire abdomen. Laboratory test results showed increased levels of inflammation, and a computed tomography scan revealed edematous intestinal wall thickening with ascites. Blood and stool cultures showed no specific findings. Since she was suspected to have developed panperitonitis with acute enterocolitis, she started treatment with an antibacterial agent under bowel rest. Her abdominal symptoms gradually improved, while diarrhea and high levels of inflammatory reaction persisted. Colonoscopy revealed discontinuous abnormal mucosal vascular patterns and ulcerations in the whole colon except for the rectum, and histological analyses of the intestine demonstrated transmural mucosal infiltration of inflammatory cells without epithelioid granuloma or amyloid deposition. Based on these findings, she was diagnosed with entero BD. Meanwhile, pedal edema appeared during her hospitalization. Urinalysis results were consistent with nephrotic syndrome, thus a renal biopsy was performed. Light microscopy showed no obvious glomerular and interstitial abnormalities, whereas electron microscopy revealed foot process effacement without immune complex deposition or fibrillary structure, compatible with minimal change disease (MCD). Only with conservative therapy, her proteinuria decreased, followed by a complete remission in 3 weeks from the onset of edema. The coincident episode of MCD was finally diagnosed as renal BD that paralleled disease activity to entero BD. She started adalimumab administration, resulting in the further improvement of diarrhea and inflammatory levels.

Conclusions

This is the first report to demonstrate MCD as renal involvement of BD along with the disease activity of entero BD.

Toceranib phosphate-associated nephrotic syndrome in a dog: a case report

Background

Nephrotic syndrome (NS) is rare in dogs and is characterized by concurrent clinical findings of proteinuria, hyperlipidemia, hypoalbuminemia, and edema. NS has been reported in humans receiving tyrosine kinase inhibitors (TKI) and in dogs receiving masitinib. This is the first report of NS in a dog receiving toceranib phosphate.

Case presentation

An 8-year-old, female, spayed Labrador retriever was diagnosed with a 10 cm mast cell tumor on the left lateral abdomen. After completion of a 12-week vinblastine and prednisone protocol, she began treatment with toceranib phosphate (2.6 mg/kg by mouth, every other day). Proteinuria was documented prior to starting toceranib. On day 426 after diagnosis (day 328 of toceranib phosphate treatment), the dog was evaluated for diarrhea, lethargy and anorexia. On physical examination, dependent edema was noted on the ventral chest and abdomen, and sterile neutrophilic inflammation was aspirated from a 2.3 cm splenic nodule. The following laboratory values were reported: albumin < 1.5 g/dL; cholesterol 378 mg/dl and urine protein to creatinine ratio of 3.79. The patient was diagnosed with NS, and treatment with toceranib phosphate was discontinued. Low-dose aspirin was started in addition to an increased dosage of enalapril (0.47 mg/kg q12hr). No other therapy was instituted. The dog improved clinically, and laboratory values returned to near normal over the 8-week follow-up. She was euthanized 1399 days after discontinuing toceranib phosphate with progressive disease.

Conclusions

Nephrotic syndrome is a potential adverse event associated with the drug toceranib phosphate which may be reversible with discontinuation of treatment. Careful monitoring of urine protein, serum biochemistry, blood pressure and patient weight is advisable during treatment with toceranib phosphate.

MicroRNAs in childhood nephrotic syndrome

The discovery of microRNAs (miRNAs) has opened up new avenues of research to understand the molecular basis of a number of diseases. Because of their conservative feature in evolution and important role in the physiological function, microRNAs could be treated as predictors for disease classification and clinical process based on the specific expression. The identification of novel miRNAs and their target genes can be considered as potential targets for novel drugs. Furthermore, currently, the circulatory and urinary exosomal miRNAs are gaining increasing attention as their expression profiles are often associated with specific diseases, and they exhibit great potential as noninvasive or minimally invasive biomarkers for the diagnosis of various diseases. The remarkable stability of these extracellular miRNAs circulating in the blood or excreted in the urine underscored their key importance as biomarkers of certain diseases. There is voluminous literature concerning the role of microRNAs in other diseases, such as cardiovascular diseases, diabetic nephropathy, and so forth. However, little is known about their diagnostic ability for the pediatric nephrotic syndrome (NS). The present review article highlights the recent advances in the role of miRNAs in the pathogenesis and molecular basis of NS with an aim to bring new insights into further research applications for the development of new therapeutic agents for NS.

Metformin ameliorates the severity of experimental Alport syndrome

Metformin is widely used for the treatment of type 2 diabetes, and increasing numbers of studies have shown that metformin also ameliorates tumor progression, inflammatory disease, and fibrosis. However, the ability of metformin to improve non-diabetic glomerular disease and chronic kidney disease (CKD) has not been explored. To investigate the effect of metformin on non-diabetic glomerular disease, we used a mouse model of Alport syndrome (Col4a5 G5X) which were treated with metformin or losartan, used as a control treatment. We also investigated the effect of metformin on adriamycin-induced glomerulosclerosis model. Pathological and biochemical analysis showed that metformin or losartan suppressed proteinuria, renal inflammation, fibrosis, and glomerular injury and extended the lifespan in Alport syndrome mice. Transcriptome analysis showed that metformin and losartan influenced molecular pathways-related to metabolism and inflammation. Metformin altered multiple genes including metabolic genes not affected by losartan. Metformin also suppressed proteinuria and glomerular injury in the adriamycin-induced glomerulosclerosis mouse model. Our results showed that metformin ameliorates the glomerular sclerosis and CKD phenotype in non-diabetic chronic glomerular diseases. Metformin may have therapeutic potential for not only diabetic nephropathy but also non-diabetic glomerular disease including Alport syndrome.

Minimal Change Disease After Elective Surgical Abortion: A Case Report

Patient: Female, 21-year-old

Final Diagnosis: Minimal change disease

Symptoms: Anasarca • proteinuria

Medication: —

Clinical Procedure: Abortion

Specialty: Nephrology

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.

PD-1 immunobiology in glomerulonephritis and renal cell carcinoma

BACKGROUND

Programmed cell death protein (PD)-1 receptors and ligands on immune cells and kidney parenchymal cells help maintain immunological homeostasis in the kidney. Dysregulated PD-1:PD-L1 binding interactions occur during the pathogenesis of glomerulopathies and renal cell carcinoma (RCC). The regulation of these molecules in the kidney is important to PD-1/PD-L1 immunotherapies that treat RCC and may induce glomerulopathies as an adverse event.

METHODS

The expression and function of PD-1 molecules on immune and kidney parenchymal cells were reviewed in the healthy kidney, PD-1 immunotherapy-induced nephrotoxicity, glomerulopathies and RCC.

RESULTS

PD-1 and/or its ligands are expressed on kidney macrophages, dendritic cells, lymphocytes, and renal proximal tubule epithelial cells. Vitamin D3, glutathione and AMP-activated protein kinase (AMPK) regulate hypoxic cell signals involved in the expression and function of PD-1 molecules. These pathways are altered in kidney disease and are linked to the production of vascular endothelial growth factor, erythropoietin, adiponectin, interleukin (IL)-18, IL-23, and chemokines that bind CXCR3, CXCR4, and/or CXCR7. These factors are differentially produced in glomerulonephritis and RCC and may be important biomarkers in patients that receive PD-1 therapies and/or develop glomerulonephritis as an adverse event CONCLUSION: By comparing the functions of the PD-1 axis in glomerulopathies and RCC, we identified similar chemokines involved in the recruitment of immune cells and distinct mediators in T cell differentiation. The expression and function of PD-1 and PD-1 ligands in diseased tissue and particularly on double-negative T cells and parenchymal kidney cells needs continued exploration. The possible regulation of the PD-1 axis by vitamin D3, glutathione and/or AMPK cell signals may be important to kidney disease and the PD-1 immunotherapeutic response.

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

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

Hypomethylation of NLRP3 gene promoter discriminates glucocorticoid-resistant from glucocorticoid-sensitive idiopathic nephrotic syndrome patients

Abstract

To assess whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid (GC)‐resistant from GC‐sensitive idiopathic nephrotic syndrome (INS), patients with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), we measured the methylation level of NLRP3 promoter in DNA from peripheral blood cells of 10 adult patients with GC‐resistant FSGS already in hemodialysis and 18 patients with GC‐sensitive INS (13 MCD/5 FSGS) and in 21 pediatric patients with INS with MCD/FSGS before starting any treatment. Association of NLRP3 inflammasome with GC resistance was recapitulated in vitro in monocytic cell lines (THP‐1 and U937). In both adults and pediatric patients, NLRP3 promoter methylation was significantly reduced in GC‐resistant compared with GC‐sensitive patients. Indeed, NLRP3 methylation distinguished GC‐resistant and GC‐sensitive patients (area under the receiver operating characteristic curve [AUROC] 86.7% in adults, p = 0.00019, and 73.5% in children, p = 0.00097). NLRP3 knock‐down augmented sensitivity to GCs in THP‐1 cells, whereas NLRP3 inflammasome activation lowered GC receptor concentration, increasing GC resistance in U937 cells. Our results uncovered a new biological mechanism by which patients with INS may acquire GC resistance, that could be used in future as a novel noninvasive diagnostic tool.

Pediatric Nephrotic Syndrome: Pharmacologic and Nutrition Management

Nephrotic syndrome is a common kidney disease during childhood that is characterized by alterations in glomerular filtration and leads to protein, fluid, and nutrient loss in the urine. Most patients experience peripheral, gravity-dependent edema; however, serious cases exhibit anasarca and ascites. Many long-term complications of the disease exist due to the underlying pathology and the therapies used for treatment, including metabolic bone disease, micronutrient deficiencies, and hyperlipidemia. Pharmacologic and nutrition interventions are key to appropriate management. Fluid and sodium restriction in combination with corticosteroids, albumin, and diuretics are used to manage edema. Steroid-sparing therapies like alkylating agents and calcineurin inhibitors and dietary modification to eliminate dairy and gluten may be warranted in patients with frequent relapses or steroid-refractory disease. Nutrition clinicians should familiarize themselves with the nuances of treating this disease to optimize care for children with nephrotic syndrome.

Secondary Minimal Change Disease Due to Pancreatic Cancer Improved by Chemotherapy

We herein describe an 82-year-old patient who presented with proteinuria and systemic edema. He was diagnosed with minimal change disease (MCD) and was found to have stage III pancreatic cancer. He could not undergo surgical resection due to invasion to the celiac artery and he was thus treated with chemotherapy. After a month of chemotherapy, his proteinuria improved to a normal level. After two months of chemotherapy, computed tomography indicated a partial response to the therapy. MCD can occur as paraneoplastic syndrome in patients with malignant disease, and chemotherapy can be effective for MCD associated with paraneoplastic syndrome.

The histopathological spectrum of kidney biopsies in patients with thymoma and myasthenia gravis: a report of 24 biopsies from a single institution

Background

Nephropathy in patients with thymic diseases such as thymoma and myasthenia gravis (MG) is rare and has been described mostly as isolated case reports. Here we evaluate a series of kidney biopsies from patients with thymoma and/or MG from a single institution in order to better define the spectrum and relative frequencies of thymic disease–associated nephropathies.

Methods

We conducted a retrospective case series study of 32 462 native kidney biopsies from January 2005 through December 2019 at Cedars-Sinai Medical Center, Los Angeles, CA, USA.

Results

Twenty-four biopsy specimens (0.07%) from patients with a history of thymoma and/or MG were identified. Two patients had repeat biopsies. The most common pathologic diagnosis that could be immunologically attributed to thymic disease was minimal change disease (MCD; 45%), followed by tubulointerstitial nephritis (TIN; 14%), immune complex (IC)-mediated glomerulonephritis (9%), membranous nephropathy (5%) and immunoglobulin A (IgA) nephropathy (5%). Interestingly, 50% of the MCD and 67% of TIN cases concomitantly showed mild IgG-dominant IC deposition in mesangial areas and/or in tubular basement membranes. In the two patients with repeat biopsies, mild mesangial IC deposition developed in the MCD patient but disappeared in the TIN patient with the second biopsy. Pathologic diagnoses unlikely related to the underlying thymic disease were diabetic glomerulosclerosis (9%), acute tubular necrosis (9%) and monoclonal Ig deposition disease (5%).

Conclusions

Thymic disease is associated with a wide spectrum of kidney diseases affecting the glomerular and tubulointerstitial compartments, often with low-grade IC deposition. These findings suggest a role of immunologic dysregulation in the pathogenesis of thymic disease–associated nephropathy.

A case of minimal change nephrotic syndrome with pregnancy

A 32-year-old Japanese woman at 8 weeks of gestation was admitted to our hospital for systemic edema, hypoalbuminemia, and severe proteinuria. The patient had a history of generalized alopecia and migraine. We diagnosed nephrotic syndrome, and renal biopsy revealed minimal change nephrotic syndrome (MCNS). We administered 1000 mg/day of methylprednisolone for 3 days. Oral corticosteroid therapy was followed by 40 mg of prednisolone daily. We carefully selected concomitant medication after considering organogenesis. Before and after renal biopsy, we administered heparin, antithrombin III, and immunoglobulin agents as appropriate. The patient achieved complete remission on day 8 of treatment and gave birth to a boy at 37 weeks of gestation without recurrence. MCNS during pregnancy is rare, and there is no established treatment. In conclusion, we present a case of a pregnant woman with MCNS during organogenesis. Early treatment initiation can provide a good prognosis for both mother and child.

Spontaneous remission of minimal change nephrotic syndrome in an elderly man

Minimal change nephrotic syndrome (MCNS) cases achieving spontaneous remission without external factors are rarely reported. We report a case of MCNS that achieved spontaneous remission without external factors that triggered its onset. An 82-year-old male patient was admitted to the hospital for close examination of nephrotic syndrome. Renal biopsy was performed and MCNS was diagnosed. Owing to the patient's age and history of foot and microvascular arteriovenous thrombosis, we did not start immunosuppressive drugs, including steroids, and opted for conservative management. After conservative treatment, proteinuria gradually decreased, and the patient achieved complete remission. Given that the patient had a history of urinary protein and thrombosis, recurrence of MCNS was considered again this time. In addition, the involvement of external factors that trigger the onset of MCNS was not found. In conclusion, in elderly-onset MCNS, clinicians generally hesitate to initiate treatment with an immunosuppressive drug, containing steroids, because of its many complications. Thus, our data provide valuable insight into MCNS.

B Lymphocyte Subsets in Children With Steroid-Sensitive Nephrotic Syndrome: A Longitudinal Study

Background: B-cell subsets may be involved in the pathogenesis of childhood steroid-sensitive nephrotic syndrome (SSNS). Horizontal control studies have shown that homeostasis of B-cell subsets changes at different stages of the SSNS. However, there is a lack of longitudinal studies that have investigated dynamic changes in B cell subpopulations. Methods: Blood samples were collected at the following time points from 15 children with SSNS treated at our hospital: before administration of steroid and after 3 days, 1 week, and 3, 6, 9, and 12 months. The proportions of circulating total B cells (CD19⁺), transitional B cells (CD19⁺CD24^highCD38^high), mature B cells (CD19⁺CD24^lowCD38^intermediate), and memory B cells (CD19⁺CD24^highCD38^-) were monitored by flow cytometry. Results: The proportion of CD19+ B cells before steroid administration was significantly higher than that observed at any other time point or in the healthy control (HC) group (p < 0.001). However, this proportion was significantly lower than that in the HC group at 12 months (p = 0.031). Transitional B cells before (%BL 9.5 ± 4.4) and 3 days after steroid administration (%BL 10.6 ± 5.1) were significantly higher than at any other time point or in the HC group (p < 0.001). Although these cells declined after the 3rd day the percentage was still significantly lower than that of the HC group at 12 months (p = 0.029). Memory B cells increased gradually after steroid administration and decreased to the normal range after 9 months. Conclusions: B cell subpopulations show dynamic changes in children with SSNS, suggesting that they are involved in the pathogenesis of the disorder. Further studies are required to determine whether this change can guide individualized treatment.

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

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

A global antiB cell strategy combining obinutuzumab and daratumumab in severe pediatric nephrotic syndrome

BACKGROUND

Steroid-sensitive nephrotic syndrome (SSNS) is, in most patients, a chronic disease with 80% experiencing at least one relapse after first flare. B cell depletion using rituximab is effective in preventing relapse in steroid-dependent (SDNS) patients but fails to maintain long-term remission following B cell recovery, possibly due to development of autoreactive long-lived plasma cells. We investigated sequential combination of antiCD20 antibody targeting all B cell subsets, and antiCD38 antibody with high plasma cell cytotoxicity in patients with uncontrolled SDNS after failure of one or several attempts at B cell depletion.

METHODS

Fourteen patients with median disease duration 7.8 years received 1000 mg/1.73 m² obinutuzumab followed by 1000 mg/1.73 m² daratumumab 2 weeks later. Oral immunosuppression was discontinued within 6 weeks, and biological monitoring performed monthly until B cell recovery.

RESULTS

Median age at treatment was 11.0 [IQR 10.4-14.4] years. B cell depletion was achieved in all patients, and B cell reconstitution occurred in all at median 9.5 months after obinutuzumab injection. After median follow-up 20.3 months (IQR 11.5-22.6), 5/14 patients relapsed including 4 within 100 days following B cell repletion. Relapse-free survival was 60% at 24 months from obinutuzumab infusion. Mild infusion reactions were reported in 3/14 patients during obinutuzumab and 4/14 during daratumumab infusions. Mild transient neutropenia (500-1000/mm³) occurred in 2/14 patients. Intravenous immunoglobulins were given to 12/14 patients due to hypogammaglobulinemia. Low IgA and IgM levels were noted in 8 and 14 patients, respectively. No severe infection was reported.

CONCLUSION

Global antiB cell strategy combining obinutuzumab and daratumumab induces prolonged peripheral B cell depletion and remission in children with difficult-to-treat SDNS.

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

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