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Numerous cases of glomerulonephritis manifesting shortly after SARS-CoV-2 vaccination have been reported, but causality remains unproven. Here, we studied the association between mRNA-based SARS-CoV-2 vaccination and new-onset glomerulonephritis using a nationwide retrospective cohort and a case-cohort design. Data from all Swiss pathology institutes processing native kidney biopsies served to calculate incidence of IgA nephropathy, pauci-immune necrotizing glomerulonephritis, minimal change disease, and membranous nephropathy in the adult Swiss population. The observed incidence during the vaccination campaign (January to August 2021) was not different from the expected incidence calculated using a Bayesian model based on the years 2015 to 2019 (incidence rate ratio 0.86, 95% credible interval 0.73-1.02) and did not cross the upper boundary of the 95% credible interval for any month. Among 111 patients 18 years and older with newly diagnosed glomerulonephritis between January and August 2021, 38.7% had received at least one vaccine dose before biopsy, compared to 39.5% of the general Swiss population matched for age and calendar-time. The estimated risk ratio for the development of new-onset biopsy-proven glomerulonephritis was not significant at 0.97 (95% confidence interval 0.66-1.42) in vaccinated vs. unvaccinated individuals. Patients with glomerulonephritis manifesting within four weeks after vaccination did not differ clinically from those manifesting temporally unrelated to vaccination. Thus, vaccination against SARS-CoV-2 was not associated with new-onset glomerulonephritis in these two complementary studies with most temporal associations between SARS-CoV-2 vaccination and glomerulonephritis likely coincidental.

Tyrosine kinase inhibitors (TKI) are anticancer agents widely used for a variety of malignancies including gastrointestinal stromal tumours (GIST). Although generally well-tolerated, TKIs have been associated with a number of adverse events including hypertension, proteinuria and nephrotic syndrome. We present the case of a 70-year-old patient with metastatic GIST on long-standing sunitinib who developed hypertension, oedema and hypoalbuminemia with a rising serum creatinine and was found to have nephrotic syndrome. Workup revealed elevated antiphospholipase A2 receptor (PLA2R) antibody IgG titres and a kidney biopsy confirmed PLA2R-positive membranous nephropathy without findings of thrombotic microangiopathy. Cessation of sunitinib led to reduction in anti-PLA2R antibody IgG titres while resumption, due to concern for cancer progression, led to worsening symptoms. Treatment with rituximab led to undetectable anti-PLA2R IgG titres. We highlight the importance of maintaining a systematic approach for evaluating nephrotic syndrome and provide a case showing that TKIs can exacerbate underlying nephrotic syndrome.

Several novel antigens have recently been characterized in membranous nephropathy (MN), but those involved in the rare cases of MN associated with inflammatory neuropathies (IN) remain elusive. Although several antibody specificities were identified in the serum, there is no evidence so far for their deposition in glomeruli. We report the case of a 73 y/o woman who was referred because of subacute onset of proximal asymmetric lower limb weakness together with ataxic gait. She was diagnosed with IN. Blood tests showed an eGFR of 73 ml/min/1.73m2, hypoalbuminemia (2.89 g/dl) and proteinuria (3.6 g/24h). Autoantibodies (ANA, ENA, DNA, LAC, anti-cardiolipin, ANCA) were undetectable. Serum Ig and complement levels were normal. A kidney biopsy with electron microscopy examination showed a classical picture of MN. Anti-PLA2R antibody was negative in the serum and PLA2R and THSD7A antigens were not detected in kidney tissue. Anti-contactin1 (CNTN1) antibody was found by ELISA at 1:100 serum dilution and shown to be mostly of IgG4 subclass by Western blot. CNTN1 antigen was co-localized with IgG4 within immune deposits by confocal microscopy. This observation suggests a pathophysiological link between IN and MN. CNTN1 should be considered as a potential candidate antigen involved in MN and tested in PLA2R negative forms associated with IN.

Chylothorax is an uncommon and serious clinical condition, typically induced by trauma, either postsurgical or accidental injury, but the mechanism of chylothorax caused by nephrotic syndrome is still unclear. Here, we report a case of primary nephrotic syndrome with membranous nephropathy (MN) in a 66-year-old man who presented with severe chylothorax. The chylothorax was managed by intercostal chest tube drainage, subcutaneous injection of enoxaparin, and treatment with anti-inflammatory agents and diuretics. After treatment, the patient's pleural effusion decreased, and the chyle gradually became clear. We discuss the causes of MN with chylothorax. We considered that the hypoproteinemia changed the permeability of mucous membranes and lymphatic vessels, leading to leakage of chylous particles and chylous pleural effusion formation. Chylothorax may also have been caused by severe tissue edema, edema of the lymphatic walls, and increased pressure, resulting in increased permeability or rupture of the lymphatic wall, and leakage of chylous fluid into the thoracic cavity. Because of its rarity, we hope this case report will improve clinicians' understanding of MN complications in primary nephrotic syndrome and provide suitable treatment options for future clinical reference.

Tubular basement membrane (TBM) deposits are very uncommon in non-lupus membranous nephropathy. We report 5 patients with membranous nephropathy and extensive TBM deposits following allogeneic hematopoietic cell transplant. Patients presented with nephrotic syndrome (3 also had acute kidney injury) late post-transplant in association with chronic graft-versus-host disease (cGVHD). Kidney biopsies revealed global subepithelial and extensive TBM immune complex deposits, accompanied by acute tubular injury (n = 4) and tubulointerstitial inflammation (n = 4). Proteomic analysis of glomeruli in 4 cases identified PLA2R in 1, with no significant protein spectra for PLA2R, THSD7A, EX1/2, NELL-1, PCDH7, NCAM1, or SEMA3B detected in the remaining 3. On follow-up (for a mean 42 months), 4 patients had complete and 1 partial remission following prednisone and/or rituximab therapy. We propose that membranous nephropathy with extensive TBM deposits is a distinctive clinicopathologic lesion associated with allogeneic hematopoietic cell transplant. Pathogenesis likely involves cGVHD-driven antibodies against glomerular and TBM components, the identity of which remains to be elucidated.

BackgroundMembranous nephropathy is an uncommon cause of nephrotic syndrome in pediatrics.MethodsWe reviewed our kidney biopsy records for patients ≤ 20 years of age with membranous nephropathy without evidence of systemic lupus erythematosus within 6 months of biopsy (January 1995-September 2020). Staining for PLA2R, NELL1, THSD7A, SEMA3B, EXT2 (3 biopsies), and IgG-subclass were performed.ResultsSixteen children (≤ 12 years) and 25 adolescents (13-20 years) were identified. Four children and 15 adolescents showed autoantigen positivity: PLA2R+/SEMA3B- (13), SEMA3B+/PLA2R+ (2), SEMA3B+/PLA2R- (1), NELL1 (1),EXT2+ (2), and THSD7A (0). Co-morbidities associated with PLA2R positivity included IPEX syndrome, active hepatitis B, Von Hippel Lindau syndrome, solitary kidney, type 1 diabetes, hyperuricemia, pregnancy (1), obesity (3), type II diabetes, H. pylori, viral prodrome, and nephrolithiasis. The SEMA3B+/PLA2R- adolescent was pregnant, the NELL1+ adolescent was obese, and the two EXT2+ adolescents eventually met the clinical criteria for lupus (4, 9 years post-biopsy). Co-morbidities among the remaining 24 patients included remote hepatitis B (2), Down's syndrome, lysinuric protein intolerance, recurrent UTIs, hypothyroidism, pregnancy (3), and obesity (2). Follow-up data was available for 12 children and 16 adolescents. Of the 12 children, 6 achieved complete remission, 4 achieved partial remission, and 2 had no response to treatment (1 transplant). Of the 16 adolescents, 4 achieved complete remission, 4 achieved partial remission, and 8 had no response to treatment (3 transplants). A child with "full-house" immunofluorescence staining achieved spontaneous disease remission.ConclusionOur non-lupus membranous nephropathy cohort represents one of the largest pediatric studies to date. A higher resolution version of the Graphical abstract is available as Supplementary information.

Patients with chronic kidney disease (CKD) are commonly at high risk of tuberculosis (TB). Conversely, TB rarely causes tubulointerstitial nephritis. A 75-year-old Japanese man who was undergoing periodic follow-ups for CKD stage G3aA3 with membranous nephropathy was diagnosed with acute kidney injury (AKI) (estimated glomerular filtration rate [eGFR]: 15 mL/min/1.73 m2) without prerenal AKI. He reported developing recent-onset cough 3 weeks prior to presenting to us. Renal biopsy revealed acute tubulointerstitial nephritis along with known membranous nephropathy. CD4+ helper T cells comprised most lymphocytes in the tubulointerstitium. Results of the interferon-gamma release assay, sputum smear test, polymerase chain reaction (PCR), and culture test were positive for TB. Chest computed tomography revealed thickening of the left bronchial wall; therefore, a diagnosis of early bronchial TB was made; his urine culture and PCR were negative for TB. At four months after TB treatment with no immunosuppressive therapy, his eGFR improved to 50 mL/min/1.73 m2, and based on this progress, the AKI was diagnosed as tuberculosis-associated tubulointerstitial nephritis (TATIN). Although TATIN typically occurs with chronic or miliary tuberculosis, it is very rare in early bronchial TB. Identification of TATIN is important in kidney diseases of unknown etiology, and treatment with anti-TB drugs is necessary.

The pathogenesis of primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) remains unknown to date. Some circulating permeability factors are being discussed. This work assessed molecule candidates for permeability in serum samples of patients with nephrotic syndrome (NS). MATERIALS AND METHODS 41 patients with chronic glomerulonephritis (CGN) were included in our study. 17 patients had FSGS, 7 patients had MCD, 5 patients had membranoproliferative glomerulonephritis (MPGN), 6 patients had IgA nephropathy, and 6 patients had membranous nephropathy (MN). The laboratory data were compared with the clinical and histological features of nephritis. Serum levels of plasminogen activator urokinase receptor (uPAR) and cardiotrophin-like cytokine factor 1 (CLCF-1)were measured by ELISA. RESULTS The serum levels of uPAR were higher in FSGS patients before treatment than in patients with other morphological forms (MCD, IgA nephropathy, MN, and MPGN). The levels of uPAR in serum did not correlate with daily proteinuria, serum creatinine/eGFR, arterial hypertension, the number of sclerosed glomeruli, or tubulointerstitial fibrosis. No correlations were found between the levels of CLCF-1 in serum and creatinine levels/glomerular filtration rate, the percentage of sclerosed glomeruli, or the severity of tubulointerstitial fibrosis. There were no significant differences between the histological variants of nephritis. However, we found correlations between CLCF-1 levels and proteinuria and lipid levels. CONCLUSION The data indicate an increase in the serum uPAR levels of FSGS before treatment. CLCF-1 levels in serum do not depend on histological forms of CGN, kidney function, or immunosuppressive treatment, but they correlate with proteinuria and serum lipids in patients with NS.

Primary membranous nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults, due to a variety of autoantibodies, most frequently against phospholipase A2 receptor (PLA2R). In severe cases or when spontaneous remission is not achieved, immunosuppression is required. Cyclical therapy, based on glucocorticoids and cyclophosphamide on alternate months for 6 months, has proven effective to induce remission and reduce the risk of end-stage renal disease. Since the early 2000s, rituximab (RTX) has emerged as a key player in the management of MN, showing overall comparable effectiveness and likely better safety compared with the cyclical regimen, despite the lack of adequately powered trials comparing the two approaches head to head. For these reasons, RTX is now considered the agent of choice for most patients with MN. However, there are still uncertainties. Around 20–40% of patients are resistant to RTX, especially in the setting of high anti-PLA2R levels, and this drug remains relatively unexplored in patients with the most severe disease. In these scenarios, although the expanding therapeutic armamentarium is probably going to provide further options, the cyclical regimen still plays a key role as a safety net. The aim of this article is to illustrate the role of cyclical therapy in the RTX era.

We report a 64-year-old caucasian woman diagnosed with membranous nephropathy secondary to alpha-1 antitrypsin deficiency (AATD). AATD is a rare autosomal codominant genetic disorder. Its clinical manifestations are mostly observed in the lungs, with early-onset emphysema. Nephropathy due to AATD is still very rare and only a few cohort studies have been reported. It has been recognised that alpha-1 antitrypsin has a protective role in the kidneys which enhances the possibility of development of kidney failure, such as nephrotic syndrome, in cases of AATD. Further clinical investigation is needed to understand the relationship between the development of nephropathy, namely membranous nephropathy, and AATD.

The association between Takayasu’s arteritis and membranous nephropathy is uncommon. We present the case of a 46-year-old man with Takayasu’s arteritis treated over 10 years by a multidisciplinary medical team. He had an atrophic left kidney due to arterial stenosis, with a basal creatinine of 1.59 mg/dL (140.55 µmol/l). Three years ago, he presented with full nephrotic syndrome, uncontrolled blood pressure, creatinine increases to 4.5 mg/dL (basal: 1.59 mg/dL), severe hypoalbuminaemia (1.4 g/dL) and albuminuria of 24.6 g per day. He underwent percutaneous biopsy of the right kidney that showed membranous nephropathy with negative PLA2R1 and positive IgG 1, 3 and 4 subclasses. After therapy with oral prednisone and cyclophosphamide, the patient’s kidney function improved, without recurrence of disease after 3 years of follow-up. Here, we present this extremely uncommon association of Takayasu’s arteritis and membranous nephropathy.

BACKGROUND: Podocyte depletion causes glomerulosclerosis, and persistent podocyte loss drives progression to ESKD. Urinary sediment podocin (u-sed Pod) mRNA excretion and urinary supernatant podocalyxin (u-sup PCX) protein have been used to monitor disease activity in glomerular diseases. However, the differences in these markers among pathologies have not been investigated. We examined the roles of these markers in kidney diseases. METHODS: From January 2013 to March 2016, early morning urine samples were collected from 12 healthy controls and 172 patients with kidney disease (n=15 patients with minor glomerular abnormality with mild proteinuria and/or microscopic hematuria, n=15 with minimal change nephrotic syndrome [MCNS], n=15 with membranous nephropathy [MN], n=60 with IgA nephropathy [IgAN], n=19 with crescentic GN [Cres GN], n=10 with lupus nephritis [LN], and n=38 with other kidney diseases). We examined u-sed Pod mRNA excretion, u-sup PCX protein, and the urinary protein-creatinine ratio (u-PCR). RESULTS: u-sed Pod mRNA excretion was significantly correlated with u-sup PCX protein (r=0.37, P

Primary membranous nephropathy (PMN) is an autoimmune disease limited to the kidney that is characterized by the presence of circulating PLAR2 antibodies in 70% of the cases and usually positivity for PLA2R and IgG4 by immunohistochemistry (IHC) staining. We report the first documented case of PMN (PLA2R positive) in a deceased kidney donor, transplanted to two different recipients and their clinical and immunological evolution through serial biopsies. Recipient A's first allograft biopsy (Day 26) was compatible with a MN with both positive PLA2R and IgG4 subepithelial deposits in IHC. The donor's preimplantation kidney biopsies were retrieved and reexamined, revealing MN, with high intensity for PLA2R and IgG4 in IHC. Recipient B's protocol allograft biopsy, performed later at 3 months, also revealed histology compatible with MN but without the presence of PLA2R nor IgG4 in IHC. At 1-year follow-up, both recipients maintain graft function. Serial protocol biopsies were performed in both patients showing disappearance of IgG4 in recipient A but the persistence of PLA2R in IHC. We can conclude that, given the reversal of PMN changes in the grafts, it could be considered to transplant a patient from an asymptomatic deceased donor with PMN as long as he maintains unaltered renal function.

AIM This meta-analysis comprehensively investigated the ef?cacy and safety of rituximab (RTX) in patients with idiopathic membranous nephropathy (IMN). METHODS We searched the MEDLINE, EMBASE and Cochrane Registry of Controlled Trials databases from January 2000 to January 2020. Studies evaluating the efficacy and safety of RTX in the treatment of IMN with nephrotic syndrome (NS) were included. RESULTS Nine studies (total of 357 patients) were included in the meta-analysis. The pooled complete response and overall response (OR) rates at 12 months were 13.2% (95% confidence interval [CI], 0.09?0.18) and 60% (95% CI, 0.48?0.72), and those at 24 months were 27.8% (95% CI, 0.22?0.34) and 66% (95% CI, 0.6?0.72), respectively. The pooled OR rates for the low-, standard-, and high-dose groups were 39.3%, 64%, and 60%, respectively, and those for the first-line and second-line groups were 58% and 54%, respectively. CONCLUSIONS Treatment of IMN with RTX has comparable efficacy to other immunosuppressive treatments (ISTs). RTX has the advantages of no requirement for steroids and lower rates adverse event and relapse rates. Patients who relapse or are resistant to other IST agents also respond to RTX. RTX-based regimens and other B-cell-targeted therapies may represent the future of IMN therapy.

Background MRNA COVID-19 vaccine is more effective than traditional vaccines due to superior immune activation. However, the impact of mRNA COVID-19 vaccine on triggering de novo/relapsing glomerulonephritis (GN) is limited. We report a case series of patients who developed new or relapsing GN post vaccination. Method We evaluated baseline characteristics, vaccine type and clinical outcomes of 13 patients from our institution who had a new diagnosis or relapse of their GN post mRNA COVID-19 vaccination. Results Of 13 patients, 8 patients were newly diagnosed GNs and 5 patients had relapse. Median age was 62 years (range 19-83 years). Autoimmune disease (38%) was the most prevalent underlying disease followed by cancer (23%). Majority of patients were white male. IgA nephropathy (IgAN) was the most common GN in our series (5 patients, 38%) followed by membranous nephropathy (MN) (3 patients, 23%). One patient with IgAN had evidence of IgA deposits prior to vaccination suggesting that the immune activation following vaccination triggered a flare of the disease. Our case series also included the first case report of tip-variant focal segmental glomerulosclerosis, NELL-1 associated MN, and atypical anti-GBM nephritis. Seventy seven percent developed acute kidney injury with the majority being KDIGO stage 1 (67%). Outcome are favorable with 80% responding to therapy. Conclusions New cases and relapse of GN can present shortly after mRNA COVID-19 vaccination. New cases of IgAN may result from unmasking of undiagnosed IgAN due to robust immune activation rather than development of new deposits.

BACKGROUND Many patients with primary membranous nephropathy have severe proteinuria unresponsive to optimized renin-angiotensin-aldosterone system inhibitors (RAASi). We evaluated the efficacy and safety of hydroxychloroquine as an adjunctive agent in membranous nephropathy (MN) treatments. METHODS We prospectively recruited 126 patients with biopsy-proven primary membranous nephropathy and urinary protein 1-8 g/day while receiving optimized RAASi treatment for ≥ 3 months and well-controlled blood pressure. Forty-three patients received hydroxychloroquine and RAASi (hydroxychloroquine-RAASi group), and 83 patients received RAASi alone (RAASi group). Treatment responses, including proteinuria reduction, complete and partial remission rates, and autoantibody against phospholipase A2 receptor (anti-PLA2R) levels, were compared between the two groups at 6 months and over the long term. RESULTS At 6 months, the effective response rate (proteinuria reduction > 30%) (57.5% vs. 28.9%, P = 0.002), clinical remission rate (35.0% vs. 15.7%, P = 0.015), and percentage change in proteinuria (- 51.7% vs. - 21.9%, P

We sought to investigate the utility of anti-PLA2R antibody as a non-invasive screening method for the diagnosis of primary MN in patients with nephrotic syndrome (NS). All consecutive patients with NS admitted in our department, between 01.01.2015 and 31.12.2019 were screened for anti-PLA2R antibodies by an ELISA assay (EUROIMMUN, Lubeck, DE). A positive anti-PLA2R serology was defined as an ELISA value over 2 RU/ml. Subsequently, all patients underwent kidney biopsy to confirm the histological diagnosis. Of the 203 patients with NS, we identified 67 patients with “high” titer of anti-PLA2R antibodies (> 20 RU/ml) and 47 patients with “intermediate” titer (2–20 RU/ml). In the entire cohort, the area under the curve (AUC) was 0.83 (95% CI 0.78–0.89; p

Introduction: Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults and can be primary or secondary. The antigenic target of antibodies in 70% of primary cases is phospholipase A2 receptor (PLA2R). The presence or absence of mesangial electron-dense deposits has been used to distinguish between primary and secondary MN. Mesangial deposits suggest MN due to lupus, infection, or other causes, though they are reported to occur in approximately 10% of primary MN. Staining for PLA2R is now frequently used for confirming a diagnosis of primary MN. If mesangial deposits predict a secondary cause, they should be more frequent in PLA2R-negative biopsies. Methods: A review of institutional kidney biopsies between March 2017 and June 2020 identified all cases of MN. Cases with a diagnosis of lupus or near “full-house” staining by immunofluorescence microscopy (IF) were excluded. Light microscopy, IF, and electron microscopy (EM) were performed. PLA2R staining was performed by IF. EM for all cases was reviewed and electron-dense deposit location, distribution, and size were determined. Results: Ninety-three cases of MN were identified, of which 86 had both PLA2R staining and EM performed. Of these, 51 cases (59%) were positive for PLA2R and 35 (41%) were negative. Mesangial electron-dense deposits were present in 22 (25.6%) of the 86 cases, including 27.5% (14/51) of PLA2R-positive cases and 22.8% (8/35) of PLA2R-negative cases. No difference was seen in size or distribution of deposits, or other features considered suggestive of secondary MN. Conclusion: PLA2R-negative cases were not more likely to have mesangial deposits than PLA2R-positive cases. Mesangial deposits should not be used as an indicator of secondary MN.

Membranous nephropathy associated with anti-PLA2 R autoantibody is a significant cause of nephrotic syndrome worldwide. Treatment remains empiric with a significant side-effect burden despite an increase in our understanding of the disease. We studied the effect of selectively removing this pathogenic autoantibody using immunoadsorption in adult patients with biopsy proven anti-PLA2 R membranous nephropathy. This was a multicenter, single-arm prospective clinical trial carried out in the United Kingdom. Twelve patients underwent five consecutive sessions of peptide GAM immunoadsorption with 12 months follow-up. Primary outcome was anti-PLA2 R titer at week 2. Secondary outcomes were safety and tolerability of therapy, antibody profile, and change in proteinuria, renal excretory function, serum albumin, total immunoglobulin, and quality of life at weeks 12, 24, and 52. Patients were also stratified by the presence or absence of the high-risk allele (heterozygous or homozygous for HLA-DQA1*05). Median pretreatment anti-PLA2 R was 702.50 U/mL, 1045.00 U/mL at week 2 (P-value .023) and 165.00 U/mL at week 52 (P-value .017). The treatment was well tolerated and safe. Two patients required rescue immunosuppression during the follow-up period. There was a significant improvement in serum albumin with a median at baseline of 20.50 g/L rising to 25.00 g/L at week 52 (P-value

Introduction: Renal dysfunction at presentation is uncommon in primary membranous nephropathy (PMN). The data on the outcome of PMN patients with renal dysfunction at outset are scarce. The objective of the current study was to report the clinical outcomes of PMN patients with renal dysfunction. Material and Methods: This prospective longitudinal observational study included PMN patients (both incident and treatment resistant) with an estimated glomerular filtration rate of 2. Immunosuppressive treatment was as per the unit’s protocol. Patients were evaluated for proteinuria, creatinine, and serum albumin at monthly intervals for 6 months, then quarterly for a year, and then biannually. Both serum and tissue anti-PLA2R were performed at baseline. Outcome: Percentage of patients achieving clinical remission. Results: Sixty-four adults met study criteria and were analysed. The median (IQR) age of the patients was 48 (40, 56) years. PMN was PLA2R related in 52 (81.3%) patients. Twenty-eight (43.8%) and 30 (46.9%) patients were in remission at 12 months and at the end of the study [median (IQR) follow up: 24 months (12, 35)], respectively. Eight (12.5%) had progressed to end-stage renal disease at the last follow-up. Median (IQR) baseline anti-PLA2R titre was 150.1 RU/mL (38.5, 308). Nineteen (61.3%) and 18 (58.1%) patients with >90% reduction in anti-PLA2R titres at 12 months were in clinical remission at 12 months and at the end of the follow-up, respectively. Both cyclical cyclophosphamide/steroids (cCYC/GC) and rituximab were equally effective in inducing remission, but rituximab had a favourable adverse event profile compared to cCYC/GC. Conclusion: To conclude, both cCYC/GC and rituximab are equally effective in inducing remission of nephrotic state with compromised renal function due to PMN. Immunosuppression induces remission in up to 50% PMN patients with CKD-stage 3–4.

A 33-year-old Japanese man with no significant past medical history was admitted to our hospital for evaluation of weight gain and pitting edema. A laboratory test confirmed nephrotic-range proteinuria. Renal biopsy showed subepithelial deposits, and membranous nephropathy (MN) was diagnosed. Closer examination clarified an active syphilis infection. After renal biopsy, we prescribed amoxicillin for 8 weeks to treat the syphilis infection. Three weeks later, the patient's proteinuria dramatically decreased. This case is of interest because syphilis can become a cause of acute-onset MN in younger adults, and the incidence of syphilis is increasing in Japan. .

Background Autoantibodies binding to podocyte antigens cause idiopathic membranous glomerulonephritis (iMGN). However, it remains elusive how autoantibodies reach the subepithelial space because the glomerular filtration barrier (GFB) is size selective and almost impermeable for antibodies. Methods Kidney biopsies from patients with iMGN, cell culture, zebrafish, and mouse models were used to investigate the role of nephronectin (NPNT) regulating microRNAs (miRs) for the GFB. Results Glomerular endothelial cell (GEC)-derived miR-192-5p and podocyte-derived miR-378a-3p are upregulated in urine and glomeruli of patients with iMGN, whereas glomerular NPNT is reduced. Overexpression of miR-192-5p and morpholino-mediated npnt knockdown induced edema, proteinuria, and podocyte effacement similar to podocyte-derived miR-378a-3p in zebrafish. Structural changes of the glomerular basement membrane (GBM) with increased lucidity, splitting, and lamellation, especially of the lamina rara interna, similar to ultrastructural findings seen in advanced stages of iMGN, were found. IgG-size nanoparticles accumulated in lucidity areas of the lamina rara interna and lamina densa of the GBM in npnt-knockdown zebrafish models. Loss of slit diaphragm proteins and severe structural impairment of the GBM were further confirmed in podocyte-specific Npnt knockout mice. GECs downregulate podocyte NPNT by transfer of miR-192-5p-containing exosomes in a paracrine manner. Conclusions Podocyte NPNT is important for proper glomerular filter function and GBM structure and is regulated by GEC-derived miR-192-5p and podocyte-derived miR-378a-3p. We hypothesize that loss of NPNT in the GBM is an important part of the initial pathophysiology of iMGN and enables autoantigenicity of podocyte antigens and subepithelial immune complex deposition in iMGN.

Statistical Analysis Plan (SAP) for detailing methods on comparing rates of cancer between patients with Membranous Nephropathy (MN) and others of the same sex and age without MN. We will analyze data from Truven Health MarketScan Research Databases (MarketScan) and the MarketScan Medicare Supplemental Database (MS-Medicare). These databases capture commercial claims from inpatient and outpatient encounters from employees and their dependents from a selection of large employers, health plans, and governmental, and public organizations.

BackgroundLow-vacuum scanning electron microscopy (LV-SEM) is applied to diagnostic renal pathology.MethodsTo demonstrate the usefulness of LV-SEM and to clarify the optimal conditions of pathology samples, we investigated the alterations of glomerular basement membrane (GBM) and podocytes in control and experimental active Heymann nephritis (AHN) rats by LV-SEM.ResultsOn week 15 following induction of AHN, spike formation on GBM with diffuse deposition of IgG and C3 developed. Using LV-SEM, diffuse crater-like protrusions were clearly noted three-dimensionally (3D) on surface of GBM in the same specimens of light microscopy (LM) and immunofluorescence (IF) studies only after removal coverslips or further adding periodic acid-silver methenamine (PAM) staining. These 3D ultrastructural findings of GBM surface could be detected in PAM-stained specimens by LV-SEM, although true GBM surface findings could not be obtained in acellular glomeruli, because some subepithelial deposits remained on surface of GBM. Adequate thickness was 1.5–5 μm for 10% formalin-fixed paraffin-embedded (FFPE) and 5–10 μm for the unfixed frozen sections. The foot processes and their effacement of podocytes could be observed by LV-SEM using 10%FFPE specimens with platinum blue (Pt-blue) staining or double staining of PAM and Pt-blue. These findings were obtained more large areas in 2.5% glutaraldehyde-fixed paraffin-embedded (2.5%GFPE) specimens.ConclusionOur findings suggest that LV-SEM is a useful assessment tool for evaluating the alterations of GBM and podocytes in renal pathology using routine LM and IF specimens, as well as 2.5%GFPE specimens.

Background: Relapsing polychondritis is a rare systemic disease characterized by recurrent inflammation, and often destruction, of cartilaginous tissues. Renal manifestations are rare. Membranous nephropathy complicating relapsing polychondritis has been reported only once previously, and there is no standardized treatment for membranous nephropathy associated with relapsing polychondritis. Case presentation: A 67-year-old Caucasian man with a history of chronic renal disease presented with 9 months of progressive dyspnea on exertion and 5 months of erythema, pain, and collapse of auricular cartilage. Imaging studies confirmed active inflammation of laryngeal, auricular, and costal cartilage and he was diagnosed with relapsing polychondritis. Patient had longstanding proteinuria and renal biopsy demonstrated membranous nephropathy. Patient initially showed renal and respiratory improvement with etanercept, a tumor necrosis factor alpha inhibitor, treatment. However, subsequent disease and treatment-related complications led to a progressive overall clinical decline and patient died approximately 1 year following relapsing polychondritis diagnosis. Conclusion: Membranous nephropathy may rarely complicate relapsing polychondritis. In our case, both the cartilaginous inflammation and the renal disease improved after treatment with tumor necrosis factor alpha blockade, however complications of existing airway disease led to recurrent hospitalizations and eventually death.

Kidney international 100(4), 753-779 (2021). doi:10.1016/j.kint.2021.05.015, Published by Elsevier, New York, NY

Disseminated infection caused by Nocardia farcinica with primary nephrotic syndrome is exceedingly rare. A 66-year-old female visited the outpatient department due to fever and fatigue who had been diagnosed as membranous nephropathy and with a long-term prednisone and immunosuppressive therapy. After lung biopsy for many times, culture from space-occupying lesion of the right lung and species identification by mass spectrometry-based methods (MALDI-TOF) revealed Nocardia farcinica. By imaging examination, space-occupying lesions from the lungs, brain, abdominal cavity and kidney were found. After 2 weeks of meropenem intravenous and up to 6 months of trimethoprim-sulfamethoxazole (TMP-SMX) therapy, our patient has remained relapse-free at that time of writing. Disseminated infection caused by Nocardia farcinica is usually subacute with complex clinical manifestations. In addition, it can be easily confused with diseases such as tumor and mycobacterial infection, and lead to fatal consequences. Therefore, we hope that we can remind clinicians considering by discussing common features of disseminated Nocardia farcinica infection.

Introduction Kidney Disease: Improving Global Outcomes (KDIGO) 2012 recommends cyclical cyclophosphamide plus glucocorticoids (GC) (modified Ponticelli regimen) or calcineurin inhibitors (CNIs) such as tacrolimus (TAC) or cyclosporine as the first-line agents for the management of primary membranous nephropathy (PMN) that is resistant to antiproteinuric therapy with renin-angiotensin system blockers. However, the long-term outcome of patients treated with CNIs is not known. Methods We report the outcomes of 70 patients randomized 1:1 to receive modified Ponticelli regimen or TAC/GC for renin-angiotensin system–resistant PMN who were prospectively followed for 6 years. Patients were followed monthly for 12 months, then quarterly for 12 months, and then every 6 months through the end of 6 years. Results At the end of 6 years, 21 (61.76%) and 9 (28.12%) patients maintained relapse-free remission in modified Ponticelli regimen and TAC/GC groups, respectively (relative risk [RR]: 2.19, 95% confidence interval [CI]: 1.23 to 4.15), and 30 (88.23%) and 17 (53.12%) patients were in remission (including relapses) in modified Ponticelli regimen and TAC/GC groups (RR: 1.66; 95% CI: 1.21 to 2.45), respectively. There was no significant difference in the proportion of patients who had a 40% decline in the estimated glomerular filtration rate (eGFR), death, or end-stage kidney disease between the groups. None of the patients treated with modified Ponticelli regimen reported a solid organ or hematological malignancy. Conclusions To conclude, in the long-term, modified Ponticelli regimen is superior to TAC/GC as first-line therapy for the management of antiproteinuric-resistant PMN., Graphical abstract

Immune check point inhibitors (ICIs) are now increasingly used for cancer therapy. At the same time, by activating the immune system, ICIs induce unique side effects, termed immune-related adverse events (irAEs). Renal irAEs, although uncommon, result in acute tubulointerstitial nephritis. Recently, because of an increase in ICI administration, renal irAEs, including glomerulonephritis, are being increasingly reported. A 69-year-old man presented with nephrotic syndrome after use of the ICI nivolumab. He underwent renal biopsy and was diagnosed with membranous nephropathy (MN) without acute tubulointerstitial nephritis. Immunofluorescence staining was negative for IgG4 and phospholipase A2 receptor (PLA2R), suggesting a malignancy-associated pattern. Oral glucocorticoid therapy was started as the standard treatment for irAEs, which resulted in complete remission of the nephrotic syndrome in 20 months. We suggest his MN was induced or accelerated by immune activation due to nivolumab. It means that ICIs possibly induce not only acute tubulointerstitial nephritis but also nephrotic syndrome due to MN as renal irAEs which is treatable with glucocorticoid.

В статье приведены данные 10-летних наблюдений авторов по использованию ритуксимаба при хронической болезни почек, вызванной гломерулонефритом, системной красной волчанкой или васкулитом. 27 взрослых пациентов (34 ± 6 лет, 10 (37 %) мужчин, 17 (63 %) женщин; продолжительность почечного заболевания составила 3,2 ± 0,3 года), 2 — с трансплантированной почкой и 6 детей получали ритуксимаб в дозе 1 г дважды с перерывом 2 недели и потом через полгода. Средняя доза ритуксимаба составила 2,4 г на курс лечения на одного больного. 86 % (23) больных была проведена нефробиопсия, 17 % (4) — дважды, 4 % (1) — трижды, CD20-позитивные клетки в нефробиоптате определяли 17 пациентам (74 %). Перед вторым введением ритуксимаба (через 6 месяцев после первого введения) проводилось исследование CD20 в сыворотке крови, при наличии любого количества клеток или сохранении активного процесса доза ритуксимаба составляла повторно по 1 г дважды. У 3 пациентов (11 %) при введении препарата на 2,00 ± 0,25 часа была аллергическая реакция на ритуксимаб. Для контроля артериального давления у гипертензивных пациентов дополнительно назначали торасемид и моксонидин после введения метилпреднизолона. Сопроводительная терапия включала назначение ингибиторов ренин-ангиотензин-альдостероновой системы и мочегонные. Для оценки эффективности терапии ритуксимабом использовали 2 показателя: уровень протеинурии (до начала лечения составил 3,7 ± 1,0 г/сут) и расчетную скорость клубочковой фильтрации (EPI) (до начала лечения — 55,50 ± 3,33 мл/мин). Общая эффективность лечения ритуксимабом в достижении ремиссии составила 74 % среди нефрологических пациентов, однако существенно отличалась при разных нозологических формах: самая высокая наблюдалась при люпус-нефрите (до 80 %), у половины пациентов с фокально-сегментарным гломерулосклерозом и мембранозной нефропатией, и абсолютно неэффективным лечение было при гранулематозе с полиангиитом при синдроме Гудпасчера. Прогностическая значимость выявления CD20 в нефробиоптате для обоснования назначения ритуксимаба требует дальнейших исследований, однако большое количество CD20 является прогностически неблагоприятным фактором. Определение CD20 в крови может быть дополнительным инструментом для обоснования сроков второго/третьего введения ритуксимаба.

Background Little population-based data exist about adults with primary nephrotic syndrome. Methods To evaluate kidney, cardiovascular, and mortality outcomes in adults with primary nephrotic syndrome, we identified adults within an integrated health care delivery system (Kaiser Permanente Northern California) with nephrotic-range proteinuria or diagnosed nephrotic syndrome between 1996 and 2012. Nephrologists reviewed medical records for clinical presentation, laboratory findings, and biopsy results to confirm primary nephrotic syndrome and assigned etiology. We identified a 1:100 time-matched cohort of adults without diabetes, diagnosed nephrotic syndrome, or proteinuria as controls to compare rates of ESKD, cardiovascular outcomes, and death through 2014, using multivariable Cox regression. Results We confirmed 907 patients with primary nephrotic syndrome (655 definite and 252 presumed patients with FSGS [40%], membranous nephropathy [40%], and minimal change disease [20%]). Mean age was 49 years; 43% were women. Adults with primary nephrotic syndrome had higher adjusted rates of ESKD (adjusted hazard ratio [aHR], 19.63; 95% confidence interval [95% CI], 12.76 to 30.20), acute coronary syndrome (aHR, 2.58; 95% CI, 1.89 to 3.52), heart failure (aHR, 3.01; 95% CI, 2.16 to 4.19), ischemic stroke (aHR, 1.80; 95% CI, 1.06 to 3.05), venous thromboembolism (aHR, 2.56; 95% CI, 1.35 to 4.85), and death (aHR, 1.34; 95% CI, 1.09 to 1.64) versus controls. Excess ESKD risk was significantly higher for FSGS and membranous nephropathy than for presumed minimal change disease. The three etiologies of primary nephrotic syndrome did not differ significantly in terms of cardiovascular outcomes and death. Conclusions Adults with primary nephrotic syndrome experience higher adjusted rates of ESKD, cardiovascular outcomes, and death, with significant variation by underlying etiology in the risk for developing ESKD.

Primary membranous nephropathy (PMN) is the most common cause of nephrotic syndrome in adults worldwide. Recent evidence confirms an autoimmune pathogenesis highlighted by the discovery of the phospholipase A2 receptor (PLA2R) antigen. PLA2R serves as both a marker and a guide for treatment. Traditional treatments, including alkylating agents and calcineurin inhibitors, have been associated with adverse risk profiles. Consequently, alternative therapies have been developed. Rituximab is a promising addition to the therapeutic armamentarium of PMN. However, there are few head-to-head trials comparing rituximab with cyclophosphamide. In this clinical review, the results of the MENTOR, STARMEN, and RI-CYCLO trials are discussed and evaluated. Based on the results of these trials, a more personalized treatment approach is needed. World J Nephrol Urol. 2021;10(1):7-11 doi: https://doi.org/10.14740/wjnu426

Membranous nephropathy (MN) constitutes a major cause of nephrotic syndrome (NS) in adults. After kidney transplantation (KTx), both recurrent and de novo MN has been reported. In addition to PLA2R and THSD7A, recent identification of neural EGFL-like-1 protein, NELL1, as a potential disease antigen has enriched our understanding of MN pathogenesis. To date, NELL1-positive MN has only been described in native kidneys, but never been diagnosed in renal allografts. We here report on a 56-year-old male kidney transplant recipient suffering from amyotrophic lateral sclerosis (ALS), who developed NS 25 years after KTx. Allograft biopsy revealed NELL1-positive MN. Using specifically established immunoblotting techniques, we detected new-onset NELL1-IgG1, IgG3, and IgG4 antibodies in the patient´s serum correlating with the course of proteinuria. While primary renal disease was undetermined, MN recurrence seemed unlikely given the long-time span since KTx. By clinical investigation of de novo etiologies, we did not detect an underlying malignancy. However, previous self-medication with dimercaptopropane sulfonate (DMPS) and alpha lipoic acid (ALA) represented a potential trigger and cessation associated with partial remission of proteinuria. This report illustrates the first case of posttransplant NS due to NELL1-positive MN. Monitoring NELL1 antibodies in the serum promise to be a non-invasive diagnostic tool guiding disease management.

Objective To investigate the changes in Treg and Th17 cells and explore the significance of Treg/Th17 balance in adult primary membranous nephropathy (PMN) patients. Materials and methods A total of 60 PMN patients and 50 healthy adults from June 2013 to October 2016 were enrolled in this study. The levels of Treg, Th17, and related cytokines were assessed. Pearson correlation was used for conducting correlation analysis. Results There was a significant increase in Th17 frequencies and IL-17 (Th17-related cytokines) in the peripheral blood mononuclear cells (PBMCs), as well as a significant decrease in Treg frequencies and IL-10 (Treg-related cytokines). The IL-17 concentrations in the peripheral blood of PMN patients were positively correlated with urinary protein, while IL-10 levels were negatively correlated with urinary protein. Protein expression of Treg transcription factor (Foxp3) was significantly low in the renal tissues of PMN patients, while the expression of IL-17 was much higher. Th17/Treg imbalance was reversed to normal after effective treatment with tacrolimus in 15 PMN patients. Conclusion These results suggested the existence of Treg/Th17 imbalance in PMN patients, showing the importance of Treg/Th17 imbalance in PMN pathogenesis.

Introduction Immunoglobulin (Ig)A nephropathy (IgAN) is the most frequently diagnosed primary glomerulonephritis worldwide. Despite the common diagnostic feature of mesangial IgA-containing immune complex deposition, the clinical course of the disease is extremely variable, with 30% of patients developing end-stage kidney disease within 20 years of diagnosis. Therefore, identifying which patients are likely to progress is paramount. Results In this pilot study, we found that urinary exosomal miR-204 expression was significantly reduced in IgAN compared with healthy subjects. However, there was no difference in miR-204 expression between IgAN and non-IgAN chronic kidney disease controls. Analysis of miR-204 expression in kidney biopsy cores by next-generation sequencing followed by quantitative polymerase chain reaction validation in independent cohorts demonstrated that expression of miR-204 was significantly lower in IgAN compared with thin-membrane nephropathy but not compared with membranous nephropathy. Patients with IgAN at high risk of future progression had significantly lower expression of miR-204 than those at low risk of progression. Cortical localization indicated that miR-204 was preferentially expressed in the interstitium compared with glomeruli in IgAN nonprogressors and that this distribution was lost in IgAN progressors. Receiver operating characteristic curve analysis between the 2 IgAN cohorts revealed an area under the curve of 0.82. In addition, miR-204 expression correlated with known clinicopathological prognostic risk factors. Importantly, incorporating miR-204 into the International IgAN risk prediction tool improved the diagnostic power of the algorithm to predict risk of progression. Conclusion Additional large-scale studies are now needed to validate the additive value of miR-204 in improving risk prediction in IgAN and more broadly in chronic kidney disease., Graphical abstract

Primary membranous nephropathy is a leading cause of adult nephrotic syndrome. The field took a major step forward with the identification of phospholipase A2 receptor (PLA2R) as a target antigen in the majority of cases and with the ability to measure circulating autoantibodies to PLA2R. Since then, the existence of additional target antigens such as thrombospondin type-1 domain-containing 7A, exostosin 1 and 2, neural EGFL like 1, and semaphorin 3B has been demonstrated. The ability to detect and monitor levels of circulating autoantibodies has opened a new window onto the humoral aspect of primary membranous nephropathy. Clinicians now rely on clinical parameters such as proteinuria, as well as levels of circulating autoantibodies against PLA2R and the results of immunofluorescence staining for PLA2R within kidney biopsy tissue, to guide the management of this disease. The relationship between immunologic and clinical disease course is consistent, but not necessarily intuitive. In addition, kidney biopsy provides only a single snapshot of disease that needs to be interpreted in light of changing clinical and serological findings. A clear understanding of these dynamic parameters is essential for staging, treatment, and management of this disease. This review aims to shed light on current knowledge regarding the development and time course of changes in the serum levels of autoantibodies against PLA2R, proteinuria, and histological findings that underlie the pathophysiology of primary membranous nephropathy.

Primary membranous nephropathy (MN) is caused by antibodies against podocyte antigens, especially the type M receptor of phospholipase A2 (PLA2R) and thrombospondin type-1 domain containing 7 A (THSD7A). This study’s aim was the determination of anti-PLA2R, anti-THSD7A serum antibodies, and anti-PLA2R renal tissue staining prevalence in a Latin population with MN, as well as evaluating their role as biomarkers for disease activity. The performance of the two anti-PLA2R serum diagnostic methods—ELISA and indirect immunofluorescence (IFI)—was evaluated for the diagnosis of MN. Fifty-nine patients, including 29 with MN, 18 with lupus membranous nephropathy (LMN) and 12 with focal and segmental glomerulosclerosis (FSGS), were evaluated for serum antibodies. Renal biopsies were also evaluated for the presence of anti-PLA2R staining. Twenty-one patients with MN were followed for 1 year. Patients with LMN and FSGS were negative for both antibodies. All 29 MN patients were negative for anti-THSD7A; 16 MN patients were positive for anti-PLA2R by ELISA and/or IFI, and 3 MN patients were positive for anti-PLA2R only by IFI. Thus, the anti-PLA2R ELISA test demonstrated 45% sensitivity and 97% specificity, while the IFI test showed, respectively, 55% and 100% in our MN patients. Among the 28 MN renal biopsies, 20 presented anti-PLA2R positive staining, corresponding to a 72% sensitivity. Positive correlations were observed between the anti-PLA2R ELISA titer and proteinuria. In conclusion, determination of anti-PLA2R antibodies in the MN Latin population showed similar rates to those reported for other populations. The anti-PLA2R serum levels correlated with MN disease activity.

Membranous nephropathy (MN) is an organ-restricted autoimmune disease mainly caused by circulating autoantibodies against podocyte antigens, including the M-type phospholipase A2 receptor (PLA2R) and thrombospondin domain-containing 7A (THSD7A). Antibodies against PLA2R are present in 70%–80% and against THSD7A in 2% of adult patients, which provides a paradigm shift in molecular diagnosis and management monitoring. Both antigens share some similar characteristics: they are expressed by podocytes and have wide tissue distributions; they are bound by autoantibodies only under nonreducing conditions, and the subtype of most autoantibodies is IgG4. However, the factors triggering autoantibody production as well as the association among air pollution, malignancy, and the pathogenesis of MN remain unclear. In this review, we discuss the similarity between the pathological mechanisms triggered by disparate antigens and their associated diseases. Furthermore, we demonstrated the possibility that PM2.5, malignancy, and gene expression specifically induce exposure of these antigens through conformational changes, molecular mimicry, or increased expression eliciting autoimmune responses. Thus, this review provides novel insights into the pathological mechanism of MN.

International audience; Exostosin (EXT) 1 and EXT2 proteins are recently discovered major components of the subepithelial deposits in a subset of patients with membranous nephropathy (MN).1,2 Although the detection of EXT1/2 seems to be a distinctive feature of MN related to systemic lupus erythematosus (SLE),1 the exact frequency of EXT-positive, SLE-associated MN (SLE-MN) and its potential clinical significance are not well determined.Here, we retrospectively evaluated 86 consecutive patients with biopsy-proven pure class 5 SLE-MN diagnosed between January 2010 and December 2018 in 2 nephropathology centers (La Pitié Salpêtrière and Tenon hospitals) in Paris, France; mixed classes (3 + 5 and 4 + 5 of the 2003 ISN/Renal Pathology Society classification)3 were excluded.

Background Identification of target antigens PLA2R, THSD7A, NELL1, or Semaphorin-3B can explain the majority of cases of primary membranous nephropathy (MN). However, target antigens remain unidentified in 15%-20% of patients. Methods A multipronged approach, using traditional and modern technologies, converged on a novel target antigen, and capitalized on the temporal variation in autoantibody titer for biomarker discovery. Immunoblotting of human glomerular proteins followed by differential immunoprecipitation and mass spectrometric analysis was complemented by laser-capture microdissection followed by mass spectrometry, elution of immune complexes from renal biopsy specimen tissue, and autoimmune profiling on a protein fragment microarray. Results These approaches identified serine protease HTRA1 as a novel podocyte antigen in a subset of patients with primary MN. Sera from two patients reacted by immunoblotting with a 51-kD protein within glomerular extract and with recombinant human HTRA1, under reducing and nonreducing conditions. Longitudinal serum samples from these patients seemed to correlate with clinical disease activity. As in PLA2R- and THSD7A- associated MN, anti-HTRA1 antibodies were predominantly IgG4, suggesting a primary etiology. Analysis of sera collected during active disease versus remission on protein fragment microarrays detected significantly higher titers of anti-HTRA1 antibody in active disease. HTRA1 was specifically detected within immune deposits of HTRA1-associated MN in 14 patients identified among three cohorts. Screening of 118 "quadruple-negative" (PLA2R-, THSD7A-, NELL1-, EXT2-negative) patients in a large repository of MN biopsy specimens revealed a prevalence of 4.2%. Conclusions Conventional and more modern techniques converged to identify serine protease HTRA1 as a target antigen in MN.

Introduction Foot process effacement and mitochondrial fission associate with kidney disease pathogenesis. Electron microscopy is the gold-standard method for their visualization, but the observable area of electron microscopy is smaller than light microscopy. It is important to develop alternative ways to quantitatively evaluate these microstructural changes because the lesion site of renal diseases can be focal. Methods We analyzed elastica-Masson trichrome (EMT) and periodic acid-Schiff (PAS) stained kidney sections using structured illumination microscopy (SIM). Results EMT staining revealed three-dimensional (3D) structures of foot process, whereas ponceau xylidine acid fuchsin azophloxine solution induced fluorescence. Conversion of foot process images into their constituent frequencies by Fourier transform showed that the concentric square of (1/4)2-(1/16)2 in the power spectra (PS) included information for normal periodic structures of foot processes. Foot process integrity, assessed by PS, negatively correlated with proteinuria. EMT-stained sections revealed fragmented mitochondria in mice with mitochondrial injuries and patients with tubulointerstitial nephritis; Fourier transform quantified associated mitochondrial injury. Quantified mitochondrial damage in patients with immunoglobulin A (IgA) nephropathy predicted a decline in estimated glomerular filtration rate (eGFR) after kidney biopsy but did not correlate with eGFR at biopsy. PAS-stained sections, excited by a 640 nm laser, combined with the coefficient of variation values, quantified subtle changes in the basement membranes of patients with membranous nephropathy stage I. Conclusions Kidney microstructures are quantified from sections prepared in clinical practice using SIM.

Aim Membranous nephropathy (MN) and primary biliary cholangitis (PBC) are autoimmune diseases that coexist in some cases and might share a common pathogenesis. In 75 - 80% of MN patients, PLA2R1 or THSD7A is the target antigen responsible for disease development, while in the remaining cases, MN pathogenesis is not clear. Our aim was to identify potential antigens playing an overlapping pathogenic role for development of both PBC and MN. Materials and methods Serum from a patient with PBC-associated MN was analyzed for MN and PBC-specific autoantibodies and kidney biopsy tissue was stained for the respective antigens. A review of the literature for published PBC-associated MN cases was performed. Results A 39-year-old male patient was diagnosed with PBC-associated MN. Serology tests revealed negativity for PLA2R1-ab and THSD7A-ab, but positivity for two PBC-specific antibodies: M2-ab and gp210-ab. Kidney biopsy was stained for both PBC-specific antigens, PDC-E2 and gp210, as well as PLA2R1 and THSD7A, showing no MN-specific positivity. Human glomerular extracts also did not contain PDC-E2 or gp210. A review of all 17 published cases of PBC-associated MN showed that 71% of patients suffered from at least one additional autoimmune disease, and different IgG-subclasses were found in the renal immune deposits of these patients. Conclusion These results indicate that both PBC-antigens are not the putative antigen(s) leading to MN development in this patient. PBC-antigens might not be directly responsible for MN development. Both diseases seem to present as autoimmune phenomena triggered by interaction between unknown factors.

Membranous lupus nephritis is a frequent cause of nephrotic syndrome in patients with systemic lupus erythematosus. It has been shown in phospholipase A2 receptor positive membranous nephropathy that known antibodies can be detected within sera, determination of the target autoantigen can have diagnostic significance, inform prognosis, and enable non-invasive monitoring of disease activity. Here we utilized mass spectrometry for antigen discovery in laser captured microdissected glomeruli from formalin-fixed paraffin embedded tissue and tissue protein G immunoprecipitation studies to interrogate immune complexes from frozen kidney biopsy tissue. We identified neural cell adhesion molecule 1 (NCAM1) to be a target antigen in some cases of membranous lupus nephritis and within rare cases of primary membranous nephropathy. The prevalence of NCAM1 association was 6.6% of cases of membranous lupus nephritis and in 2.0% of primary membranous nephropathy cases. NCAM1 was found to colocalize with IgG within glomerular immune deposits by confocal microscopy. Additionally, serum from patients with NCAM1-associated membranous nephropathy showed reactivity to NCAM1 recombinant protein on Western blotting and by indirect immunofluorescence assay, demonstrating the presence of circulating antibodies. Thus, we propose that NCAM1 is a target autoantigen in a subset of patients with membranous lupus nephritis. Future studies are needed to determine whether anti-NCAM1 antibody levels correlate with disease activity or response to therapy.

Background: Cardiovascular disease causes significant morbidity and mortality in patients with glomerulonephritis, which is increas ingly diagnosed in older individuals who may have diabetes mellitus (DM). We evaluated the impact of DM on metabolic profile, renal and cardiovascular outcomes during treatment and follow-up of individuals with glomerulonephritis. Methods: We performed a retrospective cohort study of 601 consecutive adults with biopsy-proven glomerulonephritis for factors as sociated with kidney failure, hospitalization for cardiovascular events, and death. Biopsies with isolated diabetic nephropathy were ex cluded. Results: The median patient age was 49.8 years (36.7-60.9 years) with estimated glomerular filtration rate of 56.7 mL/min/1.73㎡ (27.7-93.2 mL/min/1.73㎡). DM was present in 25.4%. The most frequent diagnoses were minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS) (29.5%), lupus nephritis (21.3%), immunoglobulin A (IgA) nephropathy (19.1%), and mem branous nephropathy (12.1%). The median follow-up was 38.8 months (interquartile range [IQR], 26.8-55.8 months). Among 511 in dividuals with lupus nephritis, anti-neutrophil cytoplasmic antibody-associated vasculitis, MCD/FSGS, membranous nephropathy, and IgA nephropathy, 52 (10.2%) developed kidney failure at a median 16.4 months (IQR, 2.3-32.2 months), while 29 (5.7%) had cardio vascular-related hospitalizations at 12.9 months (IQR, 4.8-31.8 months) and 31 (6.1%) died at 13.5 months (IQR, 2.5-42.9 months) after diagnosis. Cox regression analysis found that baseline DM was independently associated with kidney failure (adjusted hazard ratio [HR], 2.07; 95% confidence interval [CI], 1.06-4.05, p = 0.03) and cardiovascular-related hospitalization (adjusted HR, 2.69; 95% CI, 1.21-5.98, p = 0.02) but not with mortality. Conclusion: DM was strongly associated with kidney failure and hospitalization for cardiovascular events in patients with biopsy-prov en glomerulonephritis.

The first case of eosinophilic granulomatosis with polyangiitis (EGPA) simultaneously demonstrating various clinical manifestations, including retroperitoneal fibrosis (RPF) causing hydronephrosis and membranous nephropathy (MN) leading to nephrotic syndrome, is presented. There have been no previous case reports demonstrating the simultaneous onset of these three disease categories with significant complex pathologies. This case was successfully managed by providing adequate combination therapies according to each disease category, leading to complete remission (CR) of all three diseases. In conclusion, we believe this case is extremely rare and clinically suggestive, and that these findings can be applied to a future phenotype-tailored treatment strategy for EGPA.

The low effectiveness of the existing ways of treatment of glomerulonephritis (GN) requires the development of new treatment methods and profound studying of mechanisms of development of (GN). A review of modern literature data indicates a relationship between the development of (GN) with infection and activation of various components of the immune response. Pathogen-associated molecular patterns of infectious pathogens act as "danger signals" that activate Toll-like receptors of innate immune cells, as a result, a cascade of intracellular chain reactions is triggered, causing the production of growth factors and cytokines. The cytokine environment determines the pathway of differentiation of (CD 4+) helper cells into (Th1), (Th2), (Th17), and regulatory T cells (T reg). According to published data, a key link in the (GN) immunopathogenesis is an imbalance in the ratio of the activity of subpopulations of T helper cells, manifesting inhibition activity of (T reg) on a background of activation of effector cells ( T eff ) – (Th1), (Th2), (Th17). The activity of (Th1), (Th17)-cells are realized in the cellular mechanisms of the immunopathogenesis of (GN), while (Th2)-cells provide activation of the humoral component of adaptive immunity and the production of antibodies involved in the formation of immune complexes (ICs). This is a general scheme of the immunopathogenesis of (GN), which has specific variations depending on the clinical and morphological form of (GN). In post-infectious (GN), the activation of the humoral link of adaptive immunity with the formation of (ICs) and their subsequent deposition in the capillaries of the glomeruli comes to the fore. A feature of the immune complex process in patients with (IgA) nephropathy is the formation of "nephritogenic" ICs containing abnormal (IgA) (with impaired glycosylation of the IgA molecule) and anti-glycan antibodies. (ICs) isolated from patients with membranous nephropathy contain the podocyte receptor of phospholipase A2 (PLA 2 R) and anti- (PLA 2 R) autoantibodies belonging to (IgG 4). The central link in the immunopathogenesis of minimal changes in nephropathy is the development of an immediate hypersensitivity reaction. The prevalence of activation of the cellular mechanism of adaptive immunity acts as the main mechanism for the development of focal segmental nephrosclerosis.

Background Relapse of the nephrotic syndrome is co mmon among patients with primary membranous nephropathy (MN). Relapses of MN typically occur within a few years of achieving disease remission. There is limited description, to date, regarding patients with MN who have late relapse of MN, i.e., after >5 years of sustained disease remission. The objective of this case series was to report the clinical course of patients with MN who experience late relapse. Methods We analyzed the patient database of the Glomerular Kidney Disease Center at Columbia University to identify patients seen at our center who had relapse of biopsy specimen–proven MN at least 5 years after achieving sustained disease remission. Results We identified 16 patients with late relapse of MN. The median time in sustained remission before relapse was 10.2 (range, 7–29.0) years. Ten patients (63%) were diagnosed with late relapse on the basis of laboratory monitoring alone, without clinical symptoms of the nephrotic syndrome. Fourteen patients (88%) received immunosuppression during their initial presentation and late relapse. Patients had favorable long-term renal outcomes over a median 21 (range, 12–56) year follow-up period, with 14 patients (88%) in remission at study conclusion and a median decline in eGFR per year of −0.63 (range, −6.3 to 17.5) ml/min per 1.73 m2 per year. Conclusions This case series highlights a previously underappreciated, and likely rare, outcome of MN, namely, late relapse. Patients who experience late relapse, and who thus have a longer time in sustained remission, may have a more favorable long-term renal outcome.