Advances in Membranous Nephropathy Ronco, Pierre; Plaisier, Emmanuelle; Debiec, Hanna
Journal of clinical medicine,
02/2021, Letnik:
10, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Membranous nephropathy (MN) is a rare auto-immune disease where the glomerulus is targeted by circulating auto-antibodies mostly against podocyte antigens, which results in the formation of ...electron-dense immune complexes, activation of complement and massive proteinuria. MN is the most common cause of nephrotic syndrome in adults leading to severe thrombotic complications and kidney failure. This review is focused on the recent therapeutic and pathophysiological advances that occurred in the last two years. For a long time, we were lacking a head-to-head comparison between cyclophosphamide considered as the gold standard therapy and other medications, notably rituximab. Substantial progress has been achieved owing to three randomized controlled trials. MENTOR (Membranous Nephropathy Trial of Rituximab) and STARMEN (Sequential Therapy with Tacrolimus and Rituximab in Primary Membranous Nephropathy) conclusively established that calcineurin inhibitor-based regimens are slower to result in an immunologic response than rituximab or cyclophosphamide, achieve fewer complete clinical remissions, and are less likely to maintainremission. Rituximab Versus Steroids and Cyclophosphamide in the Treatment of Idiopathic Membranous Nephropathy (RI-CYCLO) suggested that competition between cyclophosphamide and rituximab remains open. Given the technological leap combining laser microdissection of glomeruli and mass spectrometry of solubilized digested proteins, four "new antigens" were discovered including NELL-1 and Semaphorin 3B in so-called primary MN, and exostosins 1 and 2 and NCAM 1 in lupus MN. NELL-1 is associated with about 8% of primary MN and is characterized by segmental immune deposits and frequent association with cancer (30%). Semaphorin 3B-associated MN usually occurs in children, often below the age of two years, where it is the main antigen, representing about 16% of non-lupus MN in childhood. Exostosins 1/2 and NCAM 1 are associated with 30% and 6% of lupus MN, respectively. Exostosins 1/2 (EXT1/2) staining is associated with a low rate of end-stage kidney disease (ESKD) even in mixed classes III/IV+V. These findings already lead to revisiting the diagnostic and therapeutic algorithms toward more personalized medicine.
Hepatitis C virus (HCV) may instigate mixed cryoglobulinemia; the most significant accompanying kidney lesion is type I membranoproliferative glomerulonephritis, usually occurring in the context of ...type II mixed cryoglobulinemia. Additionally, recent data support a link between HCV infection and proteinuria in population-based studies, raising the possibility that kidney diseases associated with HCV may be more common than previously thought. A number of strategies have been used to treat HCV-related glomerulonephritis, including antiviral agents, immunosuppressive therapies such as corticosteroids and cytotoxic agents, and plasma exchange. Limited but encouraging data about the utility of antiviral treatment in the setting of HCV-associated glomerulonephritis exist, with one pooled analysis noting a sustained viral response of 42%, albeit with significant heterogeneity. Immunosuppressive therapy may be most useful for cryoglobulinemic kidney disease, with individualized approaches considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis based on the level of proteinuria and kidney failure. Of note, rituximab, a chimeric monoclonal antibody that blocks CD20 receptors on B cells, has been reported to be effective for the treatment of mixed cryoglobulinemia symptoms, including glomerulonephritis.
Development of steroid dependency in patients with nephrotic syndrome may require a long-term multi-drug therapy at risk of drug toxicity and renal failure. Rituximab treatment reduces the steroid ...dosage and the need for immunosuppressive therapy in pediatric patients. Here we retrospectively analyze the efficacy and safety of rituximab in adult patients with steroid-dependent minimal change disease. To do this, we analyzed the outcome of all adult patients treated with rituximab for steroid-dependent minimal change nephrotic syndrome over a mean follow-up of 29.5 months (range 5.1–82 months). Seventeen patients with steroid-dependent or frequently relapsing minimal change nephrotic syndrome, unresponsive to several immunosuppressive medications, were treated with rituximab. Eleven patients had no relapses after rituximab infusion (mean follow-up 26.7 months, range 5.1–82 months) and nine of them were able to come off all other immunosuppressive drugs and steroids during follow-up. Six patients relapsed at least once after a mean time of 11.9 months (mean follow-up 34.5 months, range 16.9–50.1 months), but their immunosuppressive drug treatment could be stopped or markedly reduced during this time. No adverse events were recorded. Thus, rituximab is efficient and safe in adult patients suffering from severe steroid-dependent minimal change disease. Prospective randomized trials are needed to confirm this study.
Alport syndrome is an inherited nephropathy associated with mutations in genes encoding type IV collagen chains present in the glomerular basement membrane. COL4A5 mutations are associated with the ...major X-linked form of the disease, and COL4A3 and COL4A4 mutations are associated with autosomal recessive and dominant forms (thought to be involved in 15% and 1%-5% of the families, respectively) and benign familial hematuria. Mutation screening of these three large genes is time-consuming and expensive. Here, we carried out a combination of multiplex PCR, amplicon quantification, and next generation sequencing (NGS) analysis of three genes in 101 unrelated patients. We identified 88 mutations and 6 variations of unknown significance on 116 alleles in 83 patients. Two additional indel mutations were found only by secondary Sanger sequencing, but they were easily identified retrospectively with the web-based sequence visualization tool Integrative Genomics Viewer. Altogether, 75 mutations were novel. Sequencing the three genes simultaneously was particularly advantageous as the mode of inheritance could not be determined with certainty in many instances. The proportion of mutations in COL4A3 and COL4A4 was notably high, and the autosomal dominant forms of Alport syndrome appear more frequently than reported previously. Finally, this approach allowed the identification of large COL4A3 and COL4A4 rearrangements not described previously. We conclude that NGS is efficient, reduces screening time and cost, and facilitates the provision of appropriate genetic counseling in Alport syndrome.
Data on the clinical spectrum and therapeutic management of noninfectious mixed cryoglobulinemia vasculitis (CryoVas) in the era of hepatitis C virus screening are lacking. We analyzed data from 242 ...patients with noninfectious mixed CryoVas included in the French multicenter CryoVas survey. Baseline manifestations were purpura (75%), peripheral neuropathy (52%), arthralgia or arthritis (44%), glomerulonephritis (35%), cutaneous ulcers (16%), and cutaneous necrosis (14%). A connective tissue disease was diagnosed in 30% and B-cell non-Hodgkin lymphoma in 22%, whereas the CryoVas was considered to be essential in 48%. With the use of Cox-marginal structural models, rituximab plus corticosteroids showed the greater therapeutic efficacy compared with corticosteroids alone and alkylating agents plus corticosteroids to achieve complete clinical, renal, and immunologic responses and a prednisone dosage < 10 mg/d at 6 months. However, this regimen was also associated with severe infections, particularly when high doses of corticosteroids were used, whereas death rates did not differ between the therapeutic regimens. The role of each of these strategies remains to be defined in well-designed randomized controlled trials.
Collagen IV is a major component of basement membranes (BMs). The α1(IV) chain, encoded by the COL4A1 gene, is expressed ubiquitously and associates with the α2(IV) chain to form the α1α1α2(IV) ...heterotrimer. Several COL4A1 mutations affecting a conformational domain containing integrin-binding sites are responsible for the systemic syndrome of hereditary angiopathy, nephropathy, aneurysms, and cramps (HANAC). To analyze the pathophysiology of HANAC, Col4a1 mutant mice bearing the p.Gly498Val mutation were generated. Analysis of the skeletal muscles of Col4a1 G498V mutant animals showed morphologic characteristics of a muscular dystrophy phenotype with myofiber atrophy, centronucleation, focal inflammatory infiltrates, and fibrosis. Abnormal ultrastructural aspects of muscle BMs was associated with reduced extracellular secretion of the mutant α1α1α2(IV) trimer. In addition to muscular dystrophic features, endothelial cell defects of the muscle capillaries were observed, with intracytoplasmic accumulation of the mutant α1α1α2(IV) molecules, endoplasmic reticulum cisternae dilation, and up-regulation of endoplasmic reticulum stress markers. Induction of the unfolded protein response in Col4a1 mutant muscle tissue resulted in an excess of apoptosis in endothelial cells. HANAC mutant animals also presented with a muscular functional impairment and increased serum creatine kinase levels reflecting altered muscle fiber sarcolemma. This extensive description of the muscular phenotype of the Col4a1 HANAC murine model suggests a potential contribution of primary endothelial cell defects, together with muscle BM alterations, to the development of COL4A1 -related myopathy.
The diagnosis of malignancy in the setting of nephrotic syndrome is associated with a poor overall and kidney survival regardless of whether the glomerular disease represents a paraneoplastic ...manifestation or the cancer is a coincidental finding. The diagnosis of the neoplasia leads to consideration of antitumor therapy first, and may exclude the use of immunosuppressive agents. Although no cancer screening program has been established by nephrology societies because of the lack of evidence-based data, nephrologists usually question the cost-effectiveness of work-up for malignancy in newly diagnosed glomerulopathy. Furthermore, repeated screening during follow-up may be justified by treatment failure or early relapse despite suitable therapy, and by an excess risk of malignant diseases at months or years after the diagnosis of glomerulopathy, notably in membranous nephropathy (1). Evaluation of the risk of cancer-associated glomerulopathies is primary on the basis of patient-related risk factors and the histopathological diagnosis. Screening for cancer should include a routine evaluation, completed by targeted tests driven by each patient’s risk factors. In the case of membranous nephropathy where concerns of causative or associated malignancy are usually raised, it is important to consider whether the discovery of the new antigens M-type phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) affect the decision to undergo, and the extent of, cancer screening.
There is a need for multiplex, specific and quantitative methods to speed-up the development of acute kidney injury biomarkers and allow a more specific diagnosis. Targeted proteomic analysis ...combined with stable isotope dilution has recently emerged as a powerful option for the parallelized evaluation of candidate biomarkers. This article presents the development of a targeted proteomic assay to quantify 4 acute kidney injury biomarker candidates in urine samples. The proteins included in the assessed panel consisted of myo-inositol oxygenase (MIOX), phosphoenolpyruvate carboxykinase 1 (PCK1), neutrophil gelatinase-associated lipocalin (NGAL) and liver fatty acid-binding protein (L-FABP). The proteomic assay combined an antibody-free sample preparation and a liquid chromatography-selected reaction monitoring (LC-SRM) analysis pipeline. For accurate quantification of the selected candidates, we used PSAQ (Protein Standard Absolute Quantification) standards which are isotopically labeled versions of the target proteins. When added directly to the biological samples, these standards improve detection specificity and quantification accuracy. The multiplexed assay developed for the 4 biomarker candidates showed excellent analytical performance, in line with the recommendations of health authorities. Tests on urine from two small patient cohorts and a group of healthy donors confirmed the relevance of NGAL and L-FABP as biomarkers for AKI diagnosis. The assay is readily adaptable to other biomarker candidates and should be very useful for the simultaneous and accurate quantification of multiple biomarkers.
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•There is a need for multiplex and quantitative methods to speed-up the development of acute kidney injury biomarkers.•We report the development of a targeted proteomic assay to quantify 4 AKI biomarker candidates in urine samples.•Thanks to the use of isotopically-labeled proteins as quantification standards, the assay showed excellent performance.•The assay confirmed the relevance of NGAL and L-FABP in AKI diagnosis.
We report the overall and renal outcome in a French nationwide multicenter cohort of 119 patients with anti-glomerular basement membrane (anti-GBM) disease. Sixty-four patients (54%) had an exclusive ...renal involvement, 7 (6%) an isolated alveolar hemorrhage and 48 (40%) a combined renal and pulmonary involvement. Initial renal replacement therapy (RRT) was required in 78% of patients; 82% received plasmapheresis, 82% cyclophosphamide, and 9% rituximab. ANCA positive (28%) patients were older (70 vs. 47 years,
< 0.0001), less frequently smokers (26 vs. 54%,
= 0.03), and had less pulmonary involvement than ANCA- patients. The 5 years overall survival was 92%. Risk factors of death (
= 11, 9.2%) were age at onset HR 4.10 per decade (1.89-8.88)
= 0.003, hypertension HR 19.9 (2.52-157 0.2)
= 0.005, dyslipidemia HR 11.1 (2.72-45)
= 0.0008, and need for mechanical ventilation HR 5.20 (1.02-26.4)
= 0.047. The use of plasmapheresis was associated with better survival HR 0.29 (0.08-0.98)
= 0.046. At 3 months, 55 (46%) patients had end-stage renal disease (ESRD) vs. 37 (31%) ESRD-free and 27 (23%) unevaluable with follow-up < 3 months. ESRD patients were older, more frequently female and had a higher serum creatinine level at presentation than those without ESRD. ESRD-free survival was evaluated in patients alive without ESRD at 3 months (
= 37) using a landmark approach. In conclusion, this large French nationwide study identifies prognosis factors of renal and overall survival in anti-GBM patients.
Background
According to population-based studies, microalbuminuria is associated with subsequent cognitive decline over a 4–6-year period, because of cerebral small-vessel disease (CSVD). This ...prospective cross-sectional study (NCT02852772) was designed to evaluate whether a history of microalbuminuria is associated with subsequent cognitive decline in combined antiretroviral therapy (cART)-treated persons living with human immunodeficiency virus (PLHIVs).
Methods
From our computerized medical database, we identified 30 PLHIVs (median age 52 years), immunovirologically controlled on cART, who had microalbuminuria in 2008 and had undergone, between 2013 and 2015, a comprehensive neuropsychological assessment (NPA) including seven domains (cases): information-processing speed, motor skills, executive functions, attention/working memory, learning/memory, reasoning and verbal fluency. Forty-nine PLHIVs matched for age (median age 48 years;
p
= 0.19), sex, and year of first HIV-seropositivity without microalbuminuria in 2008 were identified and underwent the same NPA between 2013 and 2015 (controls).
Results
Cases performed less well than controls for information-processing speed (
p
= 0.01) and motor skills (
p
= 0.02), but no differences were found for the other cognitive domains and global
z
-scores. A multivariable linear-regression model adjusted for confounding factors confirmed the microalbuminuria effect for the information-processing-speed
z
score.
Conclusion
cART-treated PLHIVs with a history of microalbuminuria subsequently had worse cognitive performances for the information-processing-speed domain, possibly because of CSVD. Our observations should be considered preliminary findings of a temporal link between microalbuminuria, CSVD, and subsequent cognitive impairment.
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