SARS-CoV-2 infection and recurrence of anti-glomerular basement disease: a case report.

BACKGROUND: Anti-glomerular basement membrane disease (GBM) disease is a rare autoimmune disease causing rapidly progressive glomerulonephritis and pulmonary haemorrhage. Recently, an association between COVID-19 and anti-glomerular basement membrane (anti-GBM) disease has been proposed. We report on a patient with recurrence of anti-GBM disease after SARS-CoV-2 infection. CASE PRESENTATION: The 31-year-old woman had a past medical history of anti-GBM disease, first diagnosed 11 years ago, and a first relapse 5 years ago. She was admitted with severe dyspnoea, haemoptysis, pulmonary infiltrates and acute on chronic kidney injury. A SARS-CoV-2 PCR was positive with a high cycle threshold. Anti-GBM autoantibodies were undetectable. A kidney biopsy revealed necrotising crescentic glomerulonephritis with linear deposits of IgG, IgM and C3 along the glomerular basement membrane, confirming a recurrence of anti-GBM disease. She was treated with steroids, plasma exchange and two doses of rituximab. Pulmonary disease resolved, but the patient remained dialysis-dependent. We propose that pulmonary involvement of COVID-19 caused exposure of alveolar basement membranes leading to the production of high avidity autoantibodies by long-lived plasma cells, resulting in severe pulmonary renal syndrome. CONCLUSION: Our case supports the assumption of a possible association between COVID-19 and anti-GBM disease.

Anti-glomerular basement membrane disease: A clinicomorphological study of 16 cases.

INTRODUCTION: Antiglomerular basement membrane disease manifests as rapidly progressive glomerulonephritis and alveolar hemorrhage. It encompasses 10-15% of crescentic glomerulonephritis and is associated with poor outcome. In this study, we have elaborated on the clinical details, morphological features, and outcome of anti-GBM glomerulonephritis. MATERIALS AND METHODS: All the consecutive biopsy-proven cases of anti-GBM glomerulonephritis over a period of 4½ years were analyzed, retrospectively. RESULTS: Sixteen cases were diagnosed as anti-GBM glomerulonephritis during the study period. Twelve patients presented with rapidly progressive renal failure of which four patients required hemodialysis at the time of presentation. Goodpasture's syndrome was noted in two patients. Thirteen cases were positive for circulating anti-GBM antibodies and two patients showed double positivity for both anti-GBM antibodies and ANCA. Fifteen biopsies revealed crescentic glomerulonephritis with linear deposition of IgG along the glomerular basement membrane in all the 16 cases. CONCLUSION: Renal biopsy analysis is important in the diagnosis of Anti GBM nephritis. Morphology is an important predictor of disease progression.

Antiglomerular Basement Membrane Disease.

Antiglomerular basement membrane (anti-GBM) disease is a rare but life-threatening autoimmune vasculitis that is characterized by the development of pathogenic autoantibodies to type IV collagen antigens expressed in the glomerular and alveolar basement membranes. Once deposited in tissue, these autoantibodies incite a local capillaritis which manifests as rapidly progressive glomerulonephritis (GN) in 80 to 90% of patients, and with concurrent alveolar hemorrhage in ∼50%. A small proportion of cases may present with pulmonary disease in isolation. Serological testing for anti-GBM antibodies may facilitate rapid diagnosis, though renal biopsy is often required to confirm the presence of necrotizing or crescentic GN and linear deposition of autoantibody on the glomerular basement membrane. Alveolar hemorrhage may be evident clinically, or detected on imaging, pulmonary function testing, or bronchoscopy. Prompt treatment with plasmapheresis, cyclophosphamide, and steroids is usually indicated to remove pathogenic autoantibodies, to prevent their ongoing production, and to ameliorate end-organ inflammation. Alveolar hemorrhage is usually responsive to this treatment, and long-term respiratory sequelae are uncommon. Renal prognosis is more variable, though with aggressive treatment, independent renal function is maintained at 1 year in more than 80% of patients not requiring renal replacement therapy at presentation. Relapse in uncommon in anti-GBM disease, unless there is a concomitant antineutrophil cytoplasm antibody (present in 30-40%), in which case maintenance immunosuppression is recommended.

Treatment of Pulmonary Vasculitis.

Pulmonary vasculitis can be heterogeneous and have some pathophysiological, clinical, and biological specificities that might influence treatment choices. Main vasculitides associated with pulmonary vasculitis include antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, immune complex small vessel vasculitis, and antiglomerular basement membrane disease. Patient characteristics and association of lung involvement with other manifestations affecting disease severity may also influence treatment strategy. Alveolar hemorrhage frequently requires urgent treatment to control the underlying disease and provide supportive care such as mechanical ventilation. The level of evidence of each treatment strategy varies according to the underlying disease, but treatment is usually based on a combination of glucocorticoids and immunosuppressive agents, especially cyclophosphamide and rituximab. The role of plasma exchanges, widely used in patients with severe vasculitis, is controversial, based on results from recent prospective randomized controlled trials.

Anti-Glomerular Basement Membrane Disease.

Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune small vessel vasculitis characterized by autoreactivity to antigens in type IV collagen chains expressed in glomerular and alveolar basement membrane. The detection of circulating anti-GBM antibodies, which are shown to be directly pathogenic, is central to disease diagnosis. Clinically, anti-GBM disease usually presents with rapidly progressive glomerulonephritis with or without alveolar hemorrhage. Rapid diagnosis and early treatment are required to prevent mortality and to preserve renal function. Relapse in anti-GBM disease is uncommon. Variant and atypical forms of anti-GBM disease are increasingly recognised.

Neutrophil exocytosis induces podocyte cytoskeletal reorganization and proteinuria in experimental glomerulonephritis.

Acute glomerulonephritis is characterized by rapid glomerular neutrophil recruitment, proteinuria, and glomerular hypercellularity. The current study tested the hypothesis that the release of neutrophil granule contents plays a role in both the loss of filtration barrier leading to proteinuria and the increase in glomerular cells. Inhibition of neutrophil exocytosis with a peptide inhibitor prevented proteinuria and attenuated podocyte and endothelial cell injury but had no effect on glomerular hypercellularity in an experimental acute glomerulonephritis model in mice. Cultivation of podocytes with neutrophil granule contents disrupted cytoskeletal organization, an in vitro model for podocyte effacement and loss of filtration barrier. Activated, cultured podocytes released cytokines that stimulated neutrophil chemotaxis, primed respiratory burst activity, and stimulated neutrophil exocytosis. We conclude that crosstalk between podocytes and neutrophils contributes to disruption of the glomerular filtration barrier in acute glomerulonephritis. Neutrophil granule products induce podocyte injury but do not participate in the proliferative response of intrinsic glomerular cells.

Predicting Outcome in Patients with Anti-GBM Glomerulonephritis.

BACKGROUND AND OBJECTIVES: Large studies on long-term kidney outcome in patients with anti-glomerular basement membrane (anti-GBM) GN are lacking. This study aimed to identify clinical and histopathologic parameters that predict kidney outcome in these patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective analysis included a total of 123 patients with anti-GBM GN between 1986 and 2015 from six centers worldwide. Their kidney biopsy samples were classified according to the histopathologic classification for ANCA-associated GN. Clinical data such as details of treatment were retrieved from clinical records. The primary outcome parameter was the occurrence of ESRD. Kidney survival was analyzed using the log-rank test and Cox regression analyses. RESULTS: The 5-year kidney survival rate was 34%, with an improved rate observed among patients diagnosed after 2007 (P=0.01). In patients with anti-GBM GN, histopathologic class and kidney survival were associated (P<0.001). Only one of 15 patients with a focal class biopsy sample (≥50% normal glomeruli) developed ESRD. Patients with a sclerotic class biopsy sample (≥50% globally sclerotic glomeruli) and patients with 100% cellular crescents did not recover from dialysis dependency at presentation. In multivariable analysis, dialysis dependency at presentation (hazard ratio [HR], 3.17; 95% confidence interval [95% CI], 1.59 to 6.32), percentage of normal glomeruli (HR, 0.97; 95% CI, 0.95 to 0.99), and extent of interstitial infiltrate (HR, 2.02; 95% CI, 1.17 to 3.50) were predictors of ESRD during follow-up. CONCLUSIONS: Dialysis dependency, low percentage of normal glomeruli, and large extent of interstitial infiltrate are associated with poor kidney outcome in anti-GBM GN. Kidney outcome has improved during recent years; the success rate doubled after 2007. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_11_21_CJASNPodcast_18_1_v.mp3.

Apheresis to treat systemic vasculitis.

Apheresis has been used in the treatment of severe systemic vasculitides, in conjunction with immunosuppressive therapies, for over 40 years. The aim is to rapidly remove autoantibodies or circulating immune complexes from the plasma. The two main indications at present are vasculitis associated with Antineutrophil Cytoplasmic Antibodies (ANCAs) manifesting as severe renal involvement and/or intraalveolar hemorrhage and antiglomerular basement membrane disease (Goodpasture syndrome). The ongoing PEXIVAS randomized controlled trial is assessing plasmapheresis to treat ANCA-associated vasculitis with or without severe renal involvement or intraalveolar hemorrhage. The two main apheresis techniques used to treat systemic vasculitis are plasmapheresis (by filtration, centrifugation, or double filtration) and immunoadsorption. The advantages and drawbacks of each technique are discussed here. Whether one technique is superior over the other in the current indications has not been proven.

Anti-glomerular basement membrane glomerulonephritis following nintedanib for idiopathic pulmonary fibrosis: a case report.

BACKGROUND: We report a previously unrecognized and unreported case of a patient with anti-glomerular basement membrane glomerulonephritis following nintedanib, an orally active small molecule tyrosine kinase inhibitor. CASE PRESENTATION: A 59-year-old Caucasian woman with a history of idiopathic pulmonary fibrosis presented with severe acute kidney injury (creatinine 285 umol/L) secondary to anti-glomerular basement membrane glomerulonephritis disease 4 months after commencement of nintedanib. She had hematuria with red blood cell casts, nephrotic range proteinuria (3.5g/24 hours) and significantly elevated anti-glomerular basement membrane glomerulonephritis titers at 860 chemiluminescent units. A kidney biopsy confirmed severe crescentic glomerulonephritis with linear immunoglobulin G deposition in glomerular basement membrane. Despite the commencement of treatment with plasma exchange and cyclophosphamide, she remained dialysis dependent. Nintedanib was discontinued. CONCLUSIONS: Onset of acute anti-glomerular basement membrane glomerulonephritis was found to be associated with recent nintedanib use suggesting that nintedanib may be a potential trigger for anti-glomerular basement membrane glomerulonephritis. This case highlights the importance of close monitoring of patients receiving new targeted therapies. Management of novel targeted agents in patients receiving dialysis is challenging because of the scarcity of specific data.

Patterns of glomerulonephritis with crescents: Experience at a tertiary medical center in Saudi Arabia.

A series of 78 cases of glomerulonephritis (GN), in which renal biopsy revealed changes of GN associated with crescent formation, were reviewed. Renal pathology findings were correlated with clinical features including patient's age, renal function, and serologic findings. In most of the cases (71.8%), the crescents were due to immune complex-mediated GN. This was followed by pauci-immune GN (20.5%) and anti-glomerular basement membrane antibody (GBM) GN (7.7%). The percentage of glomeruli with crescents was the highest in cases of anti-GBM disease (mean of 93.3%), followed by pauci-immune GBM (mean of 48.2%) and immune complex GN (30.9%). In cases with the pauci- immune GN, there were additional features of glomerular injury including fibrinoid necrosis, disruption of the GBM, and rupture of Bowman's capsule. These changes were generally more pronounced in a subset of pauci-immune GN associated with serum elevation of antineutrophil cytoplasmic antibody (c-ANCA). In biopsies from patient with immune complex disease, systemic lupus erythematosus was the most common cause of crescentic GN.

Anti-glomerular basement membrane: A rare cause of renal failure in children.

Anti-glomerular basement membrane (GBM) disease is a rare cause of acute renal failure and known to have bad prognosis regarding renal functions recovery and patient survival specially when diagnosed late and presents with severe renal failure that requires dialysis. We report a case of 11-year-old child with acute renal failure secondary to anti-GBM disease and associated with antineutrophil cytoplasmic antibody-positive vasculitis. He was treated with plasmapheresis, steroids, and cyclophosphamide with recovery of his kidney functions.

Atypical presentation of anti-GBM nephritis in a 90-year-old patient.

A 90-year-old woman who had bloody diarrhoea, nausea, weakness and reduced urine output was found to have acute kidney injury. Her inflammatory markers were raised and her chest X-ray suggested an inflammatory process. She was initially suspected to have acute kidney injury secondary to dehydration and sepsis but when her autoimmune screen returned positive for antiglomerular basement membrane antibodies our diagnosis and management strategy was reconsidered. This is a case report of Goodpasture disease presenting in an elderly patient.

Original Research: Potential of urinary nephrin as a biomarker reflecting podocyte dysfunction in various kidney disease models.

Urinary nephrin is a potential non-invasive biomarker of disease. To date, however, most studies of urinary nephrin have been conducted in animal models of diabetic nephropathy, and correlations between urinary nephrin-to-creatinine ratio and other parameters have yet to be evaluated in animal models or patients of kidney disease with podocyte dysfunction. We hypothesized that urinary nephrin-to-creatinine ratio can be up-regulated and is negatively correlated with renal nephrin mRNA levels in animal models of kidney disease, and that increased urinary nephrin-to-creatinine ratio levels are attenuated following administration of glucocorticoids. In the present study, renal nephrin mRNA, urinary nephrin-to-creatinine ratio, urinary protein-to-creatinine ratio, and creatinine clearance ratio were measured in animal models of adriamycin nephropathy, puromycin aminonucleoside nephropathy, anti-glomerular basement membrane glomerulonephritis, and 5/6 nephrectomy. The effects of prednisolone on urinary nephrin-to-creatinine ratio and other parameters in puromycin aminonucleoside (single injection) nephropathy rats were also investigated. In all models tested, urinary nephrin-to-creatinine ratio and urinary protein-to-creatinine ratio increased, while renal nephrin mRNA and creatinine clearance ratio decreased. Urinary nephrin-to-creatinine ratio exhibited a significant negative correlation with renal nephrin mRNA in almost all models, as well as a significant positive correlation with urinary protein-to-creatinine ratio and a significant negative correlation with creatinine clearance ratio. Urinary protein-to-creatinine ratio exhibited a significant negative correlation with renal nephrin mRNA. Following the administration of prednisolone to puromycin aminonucleoside (single injection) nephropathy rats, urinary nephrin-to-creatinine ratio was significantly suppressed and exhibited a significant positive correlation with urinary protein-to-creatinine ratio. In addition, the decrease in number of glomerular Wilms tumor antigen-1-positive cells was attenuated, and urinary nephrin-to-creatinine ratio exhibited a significant negative correlation in these cells. In conclusion, these results suggest that urinary nephrin-to-creatinine ratio level is a useful and reliable biomarker for predicting the amelioration of podocyte dysfunction by candidate drugs in various kidney disease models with podocyte dysfunction. This suggestion will also be validated in a clinical setting in future studies.

[GOODPASTURE'S SYNDROME--CASE REPORTS]. / GOODPASTUREOV SINDROM--PRIKAZI BOLESNIKÂ.

Goodpasture's syndrome is a rare clinical entity characterized by rapidly progressive glomerulonephritis, diffuse pulmonary hemorrhage and the presence of circulating autoantibodies to the glomerular basement membrane (GBM). Autoantibodies bind to reactive epitopes of noncollagenous domain of the collagen type IV alpha-3 chain in glomerular and alveolar basement membranes. Autoantibodies activate the complement cascade resulting in tissue injury by the type II hypersensitivity reaction according to the Coombs and Gell classification of antigen-antibody reactions. Prognostic factors include the renal excretory function and the degree of renal and lung damage at the time of presentation. Prompt diagnosis and early and adequate medical treatment is vital for patients. Clinical treatment must be aggressive in order of achieving better outcome. This article describes three patients who clinically presented with renopulmonary syndrome, renal failure, hematuria, proteinuria and hemoptysis. Kidney biopsy diagnosis was crescentic glomerulonephritis due to antibodies against GBM. In all three patients we started therapy with glucocorticoids and cyclophosphamide combined with plasma exchange therapy. In two patients who initially had severe impairment of renal function and high percentage of crescents in the renal biopsy, kidney function recovery was not achieved. In one patient, who at the time of clinical presentation showed milder renal failure and lower percentage of crescents in renal biopsy, the full recovery of renal function was obtained.

An atypical case of anti-GBM antibody disease with renal function deterioration from normal to end stage renal disease

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Mammalian target of rapamycin complex 1 activation in podocytes promotes cellular crescent formation.

Podocytes play a key role in the formation of cellular crescents in experimental and human diseases. However, the underlying mechanisms for podocytes in promoting crescent formation need further investigation. Here, we demonstrated that mammalian target of rapamycin complex 1 (mTORC1) signaling was remarkably activated and hypoxia-inducible factor (HIF) 1α expression was largely induced in cellular crescents from patients with crescentic glomerular diseases. Specific deletion of Tsc1 in podocytes led to mTORC1 activation in podocytes and kidney dysfunction in mice. Interestingly, 33 of 36 knockouts developed cellular or mixed cellular and fibrous crescents at 7 wk of age (14.19±3.86% of total glomeruli in knockouts vs. 0% in control littermates, n=12-36, P=0.04). All of the seven knockouts developed crescents at 12 wk of age (30.92±11.961% of total glomeruli in knockouts vs. 0% in control littermates, n=4-7, P=0.002). Most notably, bridging cells between the glomerular tuft and the parietal basement membrane as well as the cellular crescents were immunostaining positive for WT1, p-S6, HIF1α, and Cxcr4. Furthermore, continuously administrating rapamycin starting at 7 wk of age for 5 wk abolished crescents as well as the induction of p-S6, HIF1α, and Cxcr4 in the glomeruli from the knockouts. Together, it is concluded that mTORC1 activation in podocytes promotes cellular crescent formation, and targeting this signaling may shed new light on the treatment of patients with crescentic glomerular diseases.

Modulation of heparan sulfate in the glomerular endothelial glycocalyx decreases leukocyte influx during experimental glomerulonephritis.

The glomerular endothelial glycocalyx is postulated to be an important modulator of permeability and inflammation. The glycocalyx consists of complex polysaccharides, the main functional constituent of which, heparan sulfate (HS), is synthesized and modified by multiple enzymes. The N-deacetylase-N-sulfotransferase (Ndst) enzymes initiate and dictate the modification process. Here we evaluated the effects of modulation of HS in the endothelial glycocalyx on albuminuria and glomerular leukocyte influx using mice deficient in endothelial and leukocyte Ndst1 (TEKCre+/Ndst1flox/flox). In these mice, glomerular expression of a specific HS domain was significantly decreased, whereas the expression of other HS domains was normal. In the endothelial glycocalyx, this specific HS structure was not associated with albuminuria or with changes in renal function. However, glomerular leukocyte influx was significantly reduced during antiglomerular basement membrane nephritis, which was associated with less glomerular injury and better renal function. In vitro decreased adhesion of wild-type and Ndst1-deficient granulocytes to Ndst1-silenced glomerular endothelial cells was found, accompanied by a decreased binding of chemokines and L-selectin. Thus, modulation of HS in the glomerular endothelial glycocalyx significantly reduced the inflammatory response in antiglomerular basement membrane nephritis.

Anti-glomerular basement membrane antibodies.

Basement membranes form an anatomic barrier that contains connective tissue. They are composed of type IV collagen, laminin and proteoglycans. Anti-basement membrane antibodies bind to the non-collagen site of the α3 chain of type IV collagen. A group of renal diseases, pulmonary diseases and perhaps others affecting different organs have long been associated with the presence of antibodies directed against glomerular basement membrane (GBM), alveolar basement membrane and tubular basement membrane. Goodpasture disease has a frequency of 0.5 to 1 case by million/year, and is responsible for up to 20% of crescentic glomerulonephritis in renal biopsy. It has been associated with genetic and immune abnormalities and there are usually environmental triggers preceding clinical onset. Renal disease can occur isolated or in association with pulmonary hemorrhage. In general, renal disease has a rapid progression that determines severe compromise, with rare spontaneous resolution. The diagnosis of Goodpasture disease requires the presence of the anti-GBM antibody, either in circulation or in renal tissue. The prognosis of non-treated patients is poor. The standard of care is plasma exchange combined with prednisone and cyclophosphamide. Anti-GBM antibody levels must be monitored frequently until their disappearance, and then every 6 months to confirm sustained remission in the absence of clinical signs of recurrence. Prognosis of the disease is strongly associated with its initial presentation. Survival rates are related to the degree of renal compromise at onset of the disease. Recurrence of the disease post-transplantation is low.

Complement activation contributes to the injury and outcome of kidney in human anti-glomerular basement membrane disease.

PURPOSE: Linear or granular deposition of complement 3 (C3) along glomerular basement membrane (GBM) is generally revealed in kidneys of human anti-GBM disease. However, the mechanism of complement activation and its association with clinical features and outcomes are less clear. METHODS: We measured the plasma and urinary levels of complement components, C1q, mannose-binding lectin (MBL), factor B (Ba), C3, C3a, C4, C4a, C5, C5a and soluble C5b-9 (SC5b-9), using ELISA in 20 patients with renal biopsy proven anti-GBM disease. RESULTS: The end product of complement activation, SC5b-9, was elevated both in plasma and urine. The levels of C3 and C4 were normal in plasma, while elevated in urine. The levels of C5a and SC5b-9 were increased in plasma from 15% and 30% patients respectively, while they were raised in urine from almost all patients (100% and 92%). The levels of plasma SC5b-9 and urinary C5a were positively correlated with the serum creatinine at presentation (r=0.56, P=0.01; r=0.68, P=0.02, respectively) and the percentage of crescents in glomeruli (r=0.60, P=0.005; r=0.75, P=0.005, respectively). The plasma level of SC5b-9 was further identified as the predictor for renal failure during follow up (HR, 1.46; 95% CI, 1.12-1.90; P=0.005). CONCLUSION: Complement cascade goes to the end in human anti-GBM disease and resides mainly in kidney. It plays pathogenic role in renal injury, by the possible proinflammatory effect of C5a and/or cell lysis effect of C5b-9. C5a and C5b-9 may be useful in clinical monitoring and predicting.