Th17-Immune Response in Patients With Membranous Nephropathy Is Associated With Thrombosis and Relapses

Fibrinogen-albumin ratio predicts treatment response in phospholipase A2 receptor-associated membranous nephropathy with nephrotic syndrome

BACKGROUND

The M-type phospholipase A2 receptor (PLA2R)-associated primary membranous nephropathy (PMN) is an immune-related disease in adults with increasing morbidity and variable treatment response, in which inflammation may contribute to the multifactorial immunopathogenesis. The relationship between fibrinogen-albumin ratio (FAR), serving as a novel inflammatory biomarker, and PMN is still unclear. Therefore, this study aims to clarify the association between FAR and disease activity and therapy response of PMN.

METHODS

110 biopsy-proven phospholipase A2 receptor (PLA2R) -associated PMN participants with nephrotic syndrome from January 2017 to December 2021 were recruited in the First Affiliated Hospital of Nanjing Medical University. The independent risk factors of non-remission (NR) and the predictive ability of FAR were explored by Cox regression and receiver-operating characteristic (ROC) curve analysis. According to the optimal cutoff value, study patients were categorized into the low-FAR group (≤the cutoff value) and the high-FAR group (>the cutoff value). Spearman's correlations were used to examine the associations between FAR and baseline clinicopathological characteristics. Kaplan-Meier method was used to assess the effects of FAR on remission.

RESULTS

In the entire study cohort, 78 (70.9%) patients reached complete or partial remission (CR or PR). The optimal cutoff value of FAR for predicting the remission outcome (CR + PR) was 0.233. The Kaplan-Meier survival analysis demonstrated that the high-FAR group (>0.233) had a significantly lower probability to achieve CR or PR compared to the low-FAR group (≤0.233) (Log Rank test, p = 0.021). Higher levels of FAR were identified as an independent risk factor for NR, and the high-FAR group was associated with a 2.27 times higher likelihood of NR than the low-FAR group (HR 2.27, 95% CI 1.01, 5.13, p = 0.048). These relationships remained robust with further analysis among calcineurin inhibitors (CNIs)-receivers. In the multivariate Cox regression model, the incidence of NR was 4.00 times higher in the high-FAR group than in the low-FAR group (HR 4.00, 95% CI 1.41, 11.31, p = 0.009). Moreover, ROC analysis revealed the predictive value of FAR for CR or PR with a 0.738 area under curve (AUC), and the AUC of anti-PLA2R Ab was 0.675. When combining FAR and anti-PLA2R Ab, the AUC was boosted to 0.766.

CONCLUSIONS

FAR was significantly correlated with proteinuria and anti-PLA2R Ab in PMN. As an independent risk factor for NR, FAR might serve as a potential inflammation-based prognostic tool for identifying cases with poor treatment response, and the best predictive cutoff value for outcomes was 0.233.

IL-23/IL-17 in a Paradoxical Association with Primary Membranous Nephropathy

Primary membranous nephropathy (PMN), an autoimmune disease, is the most common cause of nephrotic syndrome in middle-aged non-diabetic adults. PMN pathophysiology includes Th1/Th2 paradigm. The IL-23/IL-17 pathway is implicated in autoimmune kidney disorders, but no study has examined its relationship with PMN. In several unrelated studies, PMN patients reported to have paradoxical IL-17 levels. This manuscript describes the best possible association of IL-23/IL-17 axis with PMN. Biopsy-proven PMN patients and age, gender-matched healthy controls were enrolled. Serum-PLA2R (Euroimmune, Germany), IL-23 and IL-17 (R&D; USA), was measured using ELISA along with biochemical parameters. Appropriate statistical tools were used for analysis. One hundred eighty-nine PMN patients (mean age 41.70 ± 12.53 years) and 100 controls (mean age 43.92 ± 10.93 years) were identified. One hundred forty were PLA2R-related. PMN patients had median proteinuria, serum albumin, and creatinine of 6.12 (3.875, 9.23) g/day, 2.32 (1.96, 2.9) g/dl, and 0.89 (0.7, 1.1) mg/dl, respectively. IL-17, but not IL-23, was significantly increased in PMN patients compared to controls (IL-17, median: 12.07 pg/ml (9.75, 24.56) vs median: 9.75 pg/ml (8.23, 17.03) p = 0.0002); (IL23, median: 6.04 pg/ml (4.22, 10.82) vs median: 5.46 pg/ml (3.34, 9.96) p = 0.142). IL-17 and IL-23 correlated significantly (p 0.05) in PMN patients, and similar trend was seen when grouped into PLA2R-related and -unrelated groups. The levels of IL-23 (p = 0.057) and IL-17 (p = 0.004) were high in MN patients that did not respond to the treatment. The current finding may indicate or suggest the involvement of IL-23/IL-17 PMN pathogenesis. A comprehensive investigation is needed to evaluate IL-23/IL-17 axis with renal infiltrating immune cells, and external stimuli.

Causal effects of rheumatoid arthritis or ankylosing spondylitis on membranous nephropathy: a two-sample Mendelian randomization study

Background

Membranous nephropathy (MN) is the leading cause of adult-onset nephrotic syndrome, with primary MN of unclear cause accounting for 80% of cases. Retrospective clinical research reported that MN occurring in rheumatoid arthritis (RA) and ankylosing spondylitis (AS) patients was triggered by nephrotoxic drugs or of unknown cause. However, whether RA or AS itself increases the risk of developing MN is unknown.

Methods

We conducted mendelian randomization (MR) analysis to evaluate the causal effects of RA or AS on MN using genome-wide association study (GWAS) statistics. The inverse variance weighted (IVW) method was the primary analysis, and several supplementary analyses and sensitivity analyses were performed to test the causal estimates.

Results

We obtained 30 valid instrumental variables (IVs) of RA and 16 valid IVs of AS from large-scale open-access GWASs. The genetically predicted RA significantly increased the risk of MN [IVW odds ratios (OR) = 1.327, 95% confidence interval (CI) = (1.124, 1.565), P = 8.051 × 10-4]. Three supplementary MR analyses provided the consistent positive causal effect of RA on MN (all P < 0.05). No horizontal pleiotropy was detected by MR Egger intercept analysis (P = 0.411). However, the genetically predicted AS had no causal effect on MN by IVW and supplementary analysis (all P > 0.05).

Conclusions

Genetically predicted RA could increase the risk of MN, but genetically predicted AS was not associated with MN. Screening for kidney involvement in RA patients should be noted, and active treatment of RA will reduce the public health burden of MN.

Molecular characteristics of circulating B cells and kidney cells at the single-cell level in special types of primary membranous nephropathy

Background

Although primary membranous nephropathy (pMN) associated with podocyte autoantibodies (POS) is becoming well-known, the molecular characteristics of the specific type of pMN that is negative for podocyte autoantibodies (NEG) is still unclear.

Methods

We performed single-cell transcriptome sequencing and single-cell B cell receptor sequencing on circulating CD19+ cells and kidney cells of a NEG paediatric patient with pMN. The single-cell datasets of POS patients and healthy control individuals were included for integrative analysis.

Results

The gene expression characteristics and clonal expansion of naïve and memory B cells in the NEG patient changed significantly. We found that a group of CD38+ naïve B cells expanded in the NEG patient, which had the functional characteristics of cell activation. In addition, the conversion between immunoglobulin M (IgM)/IgD and IgG1 in the NEG patient was increased. Parietal epithelial cells (PECs) and podocytes shared similar signature genes (WT1, CLIC5), and new candidate marker genes for PECs, such as NID2, CAV1 and THY1, might contribute to the definition of cell subsets. PECs might have undergone significant changes in the disease, mainly manifested by changes in the expression of CCN2, PLAAT4 and SEPTIN2. The scores of gene sets related to extracellular matrix, cell adhesion and calcium channel in podocytes of the NEG patient was significantly increased. The gene expression of sodium transporter in a group of proximal tubule cells in the disease was significantly increased, especially SLC5A12, which might be related to the oedema of patients.

Conclusions

Our research demonstrated the cell type-specific molecular features in the circulation and kidney of the NEG pMN patient.

Identification of hub genes and their correlation with immune infiltrating cells in membranous nephropathy: an integrated bioinformatics analysis

BACKGROUND

Membranous nephropathy (MN) is a chronic glomerular disease that leads to nephrotic syndrome in adults. The aim of this study was to identify novel biomarkers and immune-related mechanisms in the progression of MN through an integrated bioinformatics approach.

METHODS

The microarray data were downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between MN and normal samples were identified and analyzed by the Gene Ontology analysis, the Kyoto Encyclopedia of Genes and Genomes analysis and the Gene Set Enrichment Analysis (GSEA) enrichment. Hub The hub genes were screened and identified by the weighted gene co-expression network analysis (WGCNA) and the least absolute shrinkage and selection operator (LASSO) algorithm. The receiver operating characteristic (ROC) curves evaluated the diagnostic value of hub genes. The single-sample GSEA analyzed the infiltration degree of several immune cells and their correlation with the hub genes.

RESULTS

We identified a total of 574 DEGs. The enrichment analysis showed that metabolic and immune-related functions and pathways were significantly enriched. Four co-expression modules were obtained using WGCNA. The candidate signature genes were intersected with DEGs and then subjected to the LASSO analysis, obtaining a total of 6 hub genes. The ROC curves indicated that the hub genes were associated with a high diagnostic value. The CD4+ T cells, CD8+ T cells and B cells significantly infiltrated in MN samples and correlated with the hub genes.

CONCLUSIONS

We identified six hub genes (ZYX, CD151, N4BP2L2-IT2, TAPBP, FRAS1 and SCARNA9) as novel biomarkers for MN, providing potential targets for the diagnosis and treatment.

Outcome of Therapies for Membranous Glomerulonephritis During Three Waves of COVID Pandemic

There is lack of clarity on immunosuppressive therapy in glomerular diseases and concomitant corona-virus infection. We retrospectively evaluated 36 patients with primary membranous nephropathy from January 2020 to December 2021 who had received immunosuppression during this period. Diagnosis of COVID-19 was made based on self-reported history of being COVID positive. History of hospitalization and oxygen therapy was noted. Four patients developed COVID-19 in this cohort, and all were infected only once. Two patients had asymptomatic disease and two were hospitalized for severe COVID-19 and had complete recovery. In immunocompromised patients, there is a high risk of infection. This observational study is an attempt to bridge the gap that immunosuppression can precipitate COVID-19 infection.

Role of antimicrobial peptide cathelicidin in thrombosis and thromboinflammation

Thrombosis is a frequent cause of cardiovascular mortality and hospitalization. Current antithrombotic strategies, however, target both thrombosis and physiological hemostasis and thereby increase bleeding risk. In recent years the pathophysiological understanding of thrombus formation has significantly advanced and inflammation has become a crucial element. Neutrophils as most frequent immune cells in the blood and their released mediators play a key role herein. Neutrophil-derived cathelicidin next to its strong antimicrobial properties has also shown to modulates thrombosis and thus presents a potential therapeutic target. In this article we review direct and indirect (immune- and endothelial cell-mediated) effects of cathelicidin on platelets and the coagulation system. Further we discuss its implications for large vessel thrombosis and consecutive thromboinflammation as well as immunothrombosis in sepsis and COVID-19 and give an outlook for potential therapeutic prospects.

Membranous nephropathy

Membranous nephropathy is a glomerulopathy, which main affected target is the podocyte, and has consequences on the glomerular basement membrane. It is more common in adults, especially over 50 years of age. The clinical presentation is nephrotic syndrome, but many cases can evolve with asymptomatic non-nephrotic proteinuria. The mechanism consists of the deposition of immune complexes in the subepithelial space of the glomerular capillary loop with subsequent activation of the complement system. Great advances in the identification of potential target antigens have occurred in the last twenty years, and the main one is the protein "M-type phospholipase-A2 receptor" (PLA2R) with the circulating anti-PLA2R antibody, which makes it possible to evaluate the activity and prognosis of this nephropathy. This route of injury corresponds to approximately 70% to 80% of cases of membranous nephropathy characterized as primary. In the last 10 years, several other potential target antigens have been identified. This review proposes to present clinical, etiopathogenic and therapeutic aspects of membranous nephropathy in a didactic manner, including cases that occur during kidney transplantation.

Canagliflozin reverses Th1/Th2 imbalance and promotes podocyte autophagy in rats with membranous nephropathy

Idiopathic membranous nephropathy is the main cause of chronic kidney disease (CKD). Studies have shown sodium-glucose co-transporter 2 (SGLT2) inhibitors significantly delay renal outcomes in patients with CKD, but the exact mechanism remains unknown. In this study, we investigated the mechanism by which the SGLT2 inhibitor canagliflozin attenuates podocyte injury by reversing the imbalance in Helper T cell 1 (Th1)/Helper T cell 2 (Th2) in peripheral blood of rats with membranous nephropathy (MN). MN rats were gavaged with canagliflozin (10 mg/kg/d) and losartan (10 mg/kg/d), respectively, for eight weeks. Compared with the MN group, the urinary ratio of total protein and the creatinine levels of the canagliflozin group decreased significantly. Canagliflozin improved the glomerulus pathological damage, increased the expression levels of podocyte marker proteins. The protective effect of canagliflozin on kidneys was more obvious than that of losartan. Treatment with canagliflozin increased the proportion of Th1 cells by 2.3 times, decreased the proportion of Th2 cells by 68.5%, and significantly restrained the synthesis of immunoglobulin G1 in B-cells and glomerulus subepithelial immune complex deposition. Co-culture of B-cells derived from MN rats with podocytes triggered the activation of phosphorylation of mTOR and ULK1 of podocytes, inhibited podocyte autophagy and resulted in podocyte injury. B-cells derived from canagliflozin treatment rats reversed these effects above. In conclusion, canagliflozin exerts a protective effect on kidneys by reversing the imbalance in Th1/Th2 cells in MN rats and restoring the autophagy of podocytes inhibited by the abnormal immunoglobulin G secretion from B-cells.

Membranous nephropathy: Clearer pathology and mechanisms identify potential strategies for treatment

Primary membranous nephropathy (PMN) is one of the common causes of adult-onset nephrotic syndrome and is characterized by autoantibodies against podocyte antigens causing in situ immune complex deposition. Much of our understanding of the disease mechanisms underpinning this kidney-limited autoimmune disease originally came from studies of Heymann nephritis, a rat model of PMN, where autoantibodies against megalin produced a similar disease phenotype though megalin is not implicated in human disease. In PMN, the major target antigen was identified to be M-type phospholipase A2 receptor 1 (PLA2R) in 2009. Further utilization of mass spectrometry on immunoprecipitated glomerular extracts and laser micro dissected glomeruli has allowed the rapid discovery of other antigens (thrombospondin type-1 domain-containing protein 7A, neural epidermal growth factor-like 1 protein, semaphorin 3B, protocadherin 7, high temperature requirement A serine peptidase 1, netrin G1) targeted by autoantibodies in PMN. Despite these major advances in our understanding of the pathophysiology of PMN, treatments remain non-specific, often ineffective, or toxic. In this review, we summarize our current understanding of the immune mechanisms driving PMN from animal models and clinical studies, and the implications on the development of future targeted therapeutic strategies.

Toxic Occupational Exposures and Membranous Nephropathy

BACKGROUND AND OBJECTIVES

Membranous nephropathy is a rare autoimmune kidney disease whose increasing prevalence in industrialized countries pleads for the involvement of an environmental factor in the development of the disease. In addition, the predominance of men in membranous nephropathy, classically attributed to biologic or genetic differences between men and women, could also be due to different occupational exposures. To support this hypothesis, we sought to describe the toxic occupational exposures of patients with membranous nephropathy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this observational epidemiologic study, we compared the occupations and toxic occupational exposures of 100 patients with membranous nephropathy with those of the general population, consisting of two cohorts of 26,734,000 and 26,500 French workers. We then compared the characteristics of patients exposed to an occupational toxic substance with those of unexposed patients.

RESULTS

Patients with membranous nephropathy worked more frequently in the construction sector than the general population (33% versus 7%, P<0.001). This difference remained significant by age and sex. They were also more frequently exposed to toxic substances, such as asbestos (16% versus 5%, P<0.001), lead (9% versus 1%, P<0.001), or organic solvents (37% versus 15%, P<0.001), than the general population. The predominance of men in the subgroup of patients occupationally exposed to toxic substances was not observed in unexposed individuals (organic solvents: 80% men versus 41%, P<0.001; asbestos: 90% men versus 55%, P=0.004). In addition, patients with phospholipase A2 receptor 1 (PLA2R1) epitope spreading were more frequently exposed to asbestos and organic solvents than patients without epitope spreading (32% versus 7%, P=0.02 and 74% versus 43%, P=0.02, respectively), with a dose-dependent effect.

CONCLUSIONS

Patients with membranous nephropathy were more frequently exposed to certain occupational toxic substances, such as asbestos and organic solvents, than the general population. This occupational exposure was more frequent in men and in patients with PLA2R1 epitope spreading.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Immunopathological Analysis in a French National Cohort of Membranous Nephropathy (IHMN), NCT04326218.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_10_25_CJN02930322.mp3.

Specific alterations of gut microbiota in patients with membranous nephropathy: A systematic review and meta-analysis

Background: The pathogenesis of idiopathic membranous nephropathy (IMN) has not yet been thoroughly clarified, and gut dysbiosis may be a contributor to IMN. However, the characterization of gut microbiota in patients with IMN remains uncertain. Methods: Cochrane Library, PubMed, China National Knowledge Internet, Web of Science, and Embase were used to search for studies through 18 May 2022. A meta-analysis based on the standardized mean difference (SMD) with 95% confidence interval (CI) was conducted on the alpha diversity index. The between-group comparison of the relative abundance of gut microbiota taxa and the beta diversity were extracted and qualitatively analyzed. Results: Five studies were included involving 290 patients with IMN, 100 healthy controls (HCs), and 129 patients with diabetic kidney disease (DKD). The quantitative combination of alpha diversity indices indicated that although bacterial richness was impaired [ACE, SMD = 0.12, (-0.28, 0.52), p = 0.55, I 2 = 0%; Chao1, SMD = -0.34, (-0.62, -0.06), p < 0.05, I 2 = 36%], overall diversity was preserved [Shannon, SMD = -0.16, (-0.64, 0.31), p = 0.50, I 2 = 53%; Simpson, SMD = 0.27, (-0.08, 0.61), p = 0.13, I 2 = 0%]. The beta diversity was significantly varied compared to HCs or DKD patients. Compared to HCs, the abundance of Proteobacteria increased, while that of Firmicutes decreased at the phylum level. Furthermore, the abundance of Lachnospira were depleted, while those of Streptococcus were enriched at the genus level. Proteobacteria and Streptococcus were also increased compared to DKD patients. Conclusions: The expansion of Proteobacteria and depletion of Lachnospira may be critical features of the altered gut microbiota in patients with IMN. This condition may play an important role in the pathogenesis of IMN and could provide bacterial targets for diagnosis and therapy.

Rituximab in patients with membranous nephropathy and kidney insufficiency

Introduction: Patients with membranous nephropathy and kidney insufficiency have an extremely high risk of progression to end-stage renal disease. Whether rituximab can effectively treat membranous nephropathy patients with renal dysfunction remains unknown at present. The aim of our study was to evaluate the effectiveness and safety of rituximab (RTX) in membranous nephropathy with kidney insufficiency.

Methods: We retrospectively analyzed the clinical data of 35 membranous nephropathy patients with kidney insufficiency administered in the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2021. Patients were followed every 1–3 months for a total of 6 months. Clinical data were collected including anti-phospholipase A2 receptor antibody (anti-PLA2R antibody) quantification, 24-h urinary protein, serum albumin, and serum creatinine. The percentage of patients who achieved clinical remission was measured.

Results: There were 7 (20%) patients who achieved complete or partial response at 6 months after RTX treatment. After 6 months of treatment, patients were clinically improved as evidenced by significant improvements in anti- PLA2R antibody titer [7.70 (5.72, 16.72) vs. 59.20 (17.70, 187.50) RU/ml, p < 0.001], 24-h urine protein [7.04 (4.43, 8.90) vs. 10.15 (4.83, 13.57) g/d, p < 0.001], serum albumin [30.55 (24.97, 33.27) vs. 21.40 (16.75, 25.00)g/L, p < 0.001], serum creatinine [99.50 (75.25, 140.25) vs. 152.00 (134.50, 232.50) µmol/L, p = 0.022], and estimated glomerular filtration rate (eGFR) [78.29 (50.15, 101.55) vs. 41.12 (26.53, 51.41) ml/min/1.73 m², p = 0.045]. There were no significantly differences between responders and nonresponders in the baseline levels of anti-PLA2R antibodies, proteinuria, serum albumin, and renal function. After the RTX treatment, anti-PLA2R antibodies turned negative in all responders, but the antibody level persisted maintained positive in all but 5 nonresponders. The patients who achieved response maintained a stable kidney function during the study period, with eGFR 29.03 (28.76, 35.07) ml/min/1.73 m² before rituximab treatment and 62.73 (62.34, 63.13) ml/min/1.73 m² at the end of follow-up (p = 0.053).

Conclusion: RTX therapy might be an alternative treatment in reducing proteinuria and maintaining stable renal function among membranous nephropathy patients even with kidney insufficiency.

Sirtuins as novel pharmacological targets in podocyte injury and related glomerular diseases

Podocyte injury is a major cause of proteinuria in kidney diseases, and persistent loss of podocytes leads to rapid irreversible progression of kidney disease. Sirtuins, a class of nicotinamide adenine dinucleotide-dependent deacetylases, can promote DNA repair, modify transcription factors, and regulate the cell cycle. Additionally, sirtuins play a critical role in renoprotection, particularly against podocyte injury. They also have pleiotropic protective effects on podocyte injury-related glomerular diseases, such as improving the immune inflammatory status and oxidative stress levels, maintaining mitochondrial homeostasis, enhancing autophagy, and regulating lipid metabolism. Sirtuins deficiency causes podocyte injury in different glomerular diseases. Studies using podocyte sirtuin-specific knockout and transgenic models corroborate this conclusion. Of note, sirtuin activators have protective effects in different podocyte injury-related glomerular diseases, including diabetic kidney disease, focal segmental glomerulosclerosis, membranous nephropathy, IgA nephropathy, and lupus nephritis. These findings suggest that sirtuins are promising therapeutic targets for preventing podocyte injury. This review provides an overview of recent advances in the role of sirtuins in kidney diseases, especially their role in podocyte injury, and summarizes the possible rationale for sirtuins as targets for pharmacological intervention in podocyte injury-related glomerular diseases.

Identification of molecular mechanism and key biomarkers in membranous nephropathy by bioinformatics analysis

OBJECTIVES

Membranous nephropathy (MN) is an autoimmune nephropathy. The incidence of MN is increasing gradually in recent years. Previous studies focused on antibody production, complement activation and podocyte injury in MN. However, the etiology and underlying mechanism of MN remain to be further studied.

METHODS

GSE104948 and GSE108109 of glomerular expression profile were downloaded from Gene Expression Omnibus (GEO) database, GSE47184, GSE99325, GSE104954, GSE108112, GSE133288 of renal tubule expression profile, and GSE73953 of peripheral blood mononuclear cells (PBMCs) expression profile. After data integration by Networkanalyst, differentially expressed genes (DEGs) between MN and healthy samples were obtained. DEGs were enriched in gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG), and protein-protein interaction (PPI) networks of these genes were constructed through Metascape, etc. We further understood the function of hub genes through gene set enrichment analysis (GSEA). The diagnostic value of DEGs in MN was evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

A total of 3 genes (TP53, HDAC5, and SLC2A3) were screened out. Among them, the up-regulated TP53 expression may be closely related to MN renal pathological changes. However, the expression of MN podocyte target antigen was not significantly different from that of healthy controls. In addition, the changes of Wnt signaling pathway in PBMCs and the effects of SLC2A3 on the differentiation of M2 monocyte need further study.

CONCLUSION

It is difficult to unify a specific mechanism for the changes of glomerulus, renal tubules and PBMCs in MN patients. This may be related to the pathogenesis, pathology and immune characteristics of MN. MN podocyte target antigen may not be the root cause of the disease, but a stage result in the pathogenesis process.

Advances in the Management of Primary Membranous Nephropathy and Rituximab-Refractory Membranous Nephropathy

Primary membranous nephropathy (pMN) is an auto-immune disease characterized by auto-antibodies targeting podocyte antigens resulting in activation of complement and damage to the glomerular basement membrane. pMN is the most common cause of nephrotic syndrome in adults without diabetes. Despite a very heterogeneous course of the disease, the treatment of pMN has for many years been based on uniform management of all patients regardless of the severity of the disease. The identification of prognostic markers has radically changed the vision of pMN and allowed KDIGO guidelines to evolve in 2021 towards a more personalized management based on the assessment of the risk of progressive loss of kidney function. The recognition of pMN as an antibody-mediated autoimmune disease has rationalized the use immunosuppressive drugs such as rituximab. Rituximab is now a first line immunosuppressive therapy for patients with pMN with proven safety and efficacy achieving remission in 60-80% of patients. For the remaining 20-40% of patients, several mechanisms may explain rituximab resistance: (i) decreased rituximab bioavailability; (ii) immunization against rituximab; and (iii) chronic glomerular damage. The treatment of patients with rituximab-refractory pMN remains controversial and challenging. In this review, we provide an overview of recent advances in the management of pMN (according to the KDIGO 2021 guidelines), in the understanding of the pathophysiology of rituximab resistance, and in the management of rituximab-refractory pMN. We propose a treatment decision aid based on immunomonitoring to identify failures related to underdosing or immunization against rituximab to overcome treatment resistance.

Membranous nephropathy: new pathogenic mechanisms and their clinical implications

Membranous nephropathy (MN) is characterized histomorphologically by the presence of immune deposits in the subepithelial space of the glomerular filtration barrier; its clinical hallmarks are nephrotic range proteinuria with oedema. In patients with primary MN, autoimmunity is driven by circulating autoantibodies that bind to one or more antigens on the surface of glomerular podocytes. Compared with other autoimmune kidney diseases, the understanding of the pathogenesis of MN has substantially improved in the past decade, thanks to the discovery of pathogenic circulating autoantibodies against phospholipase A₂ receptor 1 (PLA₂R1) and thrombospondin type 1 domain-containing protein 7A (THSD7A). The subsequent identification of more proteins associated with MN, some of which are also endogenous podocyte antigens, might further advance the clinical characterization of MN, including its diagnosis, treatment and prognosis. Insights from studies in patients with MN, combined with the development of novel in vivo and in vitro experimental models, have potential to improve the management of patients with MN. Characterizing the interaction between autoimmunity and local glomerular lesions provides an opportunity to develop more specific, pathogenesis-based treatments.

Anti-PLA2R antibody measured by ELISA predicts the risk of vein thrombosis in patients with primary membranous nephropathy

Background

Primary membranous nephropathy (PMN) is associated with the highest risk for developing venous thrombosis compared with other nephrotic diseases. The aim of the study was to assess the predictive value of the pathognomonic anti-phospholipase A2 receptor (PLA2R) antibody with regard to incidence of venous thrombosis in PMN.

Methods

A total of 365 in-hospital patients diagnosed with PMN were enrolled in the study. Anti-PLA2R antibody was detected by commercial enzyme-linked immunosorbent assay. Multivariate logistic regression was used to detect the independent risk factors for venous thrombosis.

Results

Thirty-seven patients (10.14%) had venous thrombosis. Patients with venous thrombosis had higher levels of cholesterol (CHOL), low-density lipoprotein (LDL), and D-dimer than those without venous thrombosis (p < .05). Patients with venous thrombosis had significantly lower levels of albumin (23.95 ± 5.53 vs. 26.18 ± 6.59 g/L, p = .049). No significant differences were found in proteinuria, serum creatinine, estimated glomerular filtration rate, platelets, and fibrinogen between patients with and without thrombosis. Anti-PLA2R antibody levels in patients with venous thrombosis were significantly higher than in patients without it (p = .002). In the univariate logistic regression, Ln anti-PLA2R antibody (OR: 1.340; p = .004), albumin (OR: 0.945; p = .050), CHOL (OR: 1.191; p = .006), and LDL (OR: 1.271, p = .006) were associated with venous thrombosis. Ln anti-PLA2R antibody (OR = 1.269; 95%CI: 1.032–1.561), and LDL (OR = 1.213; 95%CI: 1.017–1.448) were the independent risk factors for venous thrombosis (p < .05) in multivariate analysis.

Conclusions

Anti-PLA2R antibody was the independent risk factor for venous thrombosis in PMN. Larger prospective studies were warranted to verify the results in future.

Strategies Towards Antigen-Specific Treatments for Membranous Nephropathy

Membranous nephropathy (MN) is a rare but potentially severe autoimmune disease and a major cause of nephrotic syndrome in adults. Traditional treatments for patients with MN include steroids with alkylating agents such as cyclophosphamide or calcineurin inhibitors such as cyclosporine, which have an undesirable side effect profile. Newer therapies like rituximab, although superior to cyclosporine in maintaining disease remission, do not only affect pathogenic B or plasma cells, but also inhibit the production of protective antibodies and therefore the ability to fend off foreign organisms and to respond to vaccination. These are undesired effects of general B or plasma cell-targeted treatments. The discovery of several autoantigens in patients with MN offers the great opportunity for more specific treatment approaches. Indeed, such treatments were recently developed for other autoimmune diseases and tested in different preclinical models, and some are about to jump to clinical practice. As such treatments have enormous potential to enhance specificity, efficacy and compatibility also for MN, we will discuss two promising strategies in this perspective: The elimination of pathogenic antibodies through endogenous degradation systems and the depletion of pathogenic B cells through chimeric autoantibody receptor T cells.

Effectiveness of rituximab vs. ocrelizumab for the treatment of primary progressive multiple sclerosis: a real-world observational study

INTRODUCTION

Ocrelizumab, an antiCD-20 antibody, is the only drug approved to treat patients with primary progressive multiple sclerosis (pwPPMS). Not all candidates receive this treatment due to prescription limitations. Rituximab, another antiCD-20 antibody, has been used off-label in pwPPMS before and after ocrelizumab approval. However, studies comparing effectiveness of both drugs are lacking.

OBJECTIVE

To evaluate effectiveness of rituximab and ocrelizumab in pwPPMS under real-life conditions.

METHODS

We conducted a multicentric observational study of pwPPMS that started ocrelizumab or rituximab according to clinical practice, with a minimum follow-up of 1 year. Data was collected prospectively and retrospectively. Primary outcome was time to confirmed disability progression at 3 months (CDW). Secondary outcome was serum neurofilament light chain levels (sNFL) at the end of follow-up.

RESULTS

95 out 111 pwPPMS fulfilled inclusion criteria and follow-up data availability: 49 (51.6%) received rituximab and 46 (48.4%) ocrelizumab. Rituximab-treated patients had significantly higher baseline EDSS, disease duration and history of previous disease-modifying treatment (DMT) than ocrelizumab-treated patients. After a mean follow-up of 18.3 months (SD 5.9), 26 patients experienced CDW (21.4%); 15 (30.6%) in the rituximab group; and 11 (23.9%) in the ocrelizumab group. Survival analysis revealed no differences in time to CDW. sNFL were measured in 60 patients and no differences between groups were found.

INTERPRETATION

We provide real-world evidence of effectiveness of ocrelizumab and rituximab in pwPPMS. No differences in time to CDW were found between treatments. However, this study cannot establish equivalence of treatments and warrant clinical trial to confirm our findings.

Biological Role, Mechanism of Action and the Importance of Interleukins in Kidney Diseases

Each year, the number of patients who are diagnosed with kidney disease too late is increasing, which leads to permanent renal failure. This growing problem affects people of every age, sex and origin, and its full etiopathogenesis is not fully understood, although the involvement of genetic susceptibility, infections, immune disorders or high blood pressure is suggested. Difficulties in making a correct and quick diagnosis are caused by the lack of research on early molecular markers, as well as educational and preventive activities among the public, which leads to the late detection of kidney diseases. An important role in the homeostasis and disease progression, including kidney diseases, is attributed to interleukins, which perform several biological functions and interact with other cells and tissues of the body. The aim of this article was to systematize the knowledge about the biological functions performed by interleukins in humans and their involvement in kidney diseases development. In our work, we took into account the role of interleukins in acute and chronic kidney disease and kidney transplantation.

MicroRNAs: Potential mediators between particulate matter 2.5 and Th17/Treg immune disorder in primary membranous nephropathy

Primary membranous nephropathy (PMN), is an autoimmune glomerular disease and the main reason of nephrotic syndrome in adults. Studies have confirmed that the incidence of PMN increases yearly and is related to fine air pollutants particulate matter 2.5 (PM2.5) exposure. These imply that PM2.5 may be associated with exposure to PMN-specific autoantigens, such as the M-type receptor for secretory phospholipase A2 (PLA2R1). Emerging evidence indicates that Th17/Treg turns to imbalance under PM2.5 exposure, but the molecular mechanism of this process in PMN has not been elucidated. As an important indicator of immune activity in multiple diseases, Th17/Treg immune balance is sensitive to antigens and cellular microenvironment changes. These immune pathways play an essential role in the disease progression of PMN. Also, microRNAs (miRNAs) are susceptible to external environmental stimulation and play link role between the environment and immunity. The contribution of PM2.5 to PMN may induce Th17/Treg imbalance through miRNAs and then produce epigenetic affection. We summarize the pathways by which PM2.5 interferes with Th17/Treg immune balance and attempt to explore the intermediary roles of miRNAs, with a particular focus on the changes in PMN. Meanwhile, the mechanism of PM2.5 promoting PLA2R1 exposure is discussed. This review aims to clarify the potential mechanism of PM2.5 on the pathogenesis and progression of PMN and provide new insights for the prevention and treatment of the disease.

Course monitoring of membranous nephropathy: Both autoantibodies and podocytes require multidimensional attention

A variety of podocyte antigens have been identified in human membranous nephropathy (MN), which is divided into various antigen-dominated subtypes, confirming the concept that MN is the common pattern of glomerular injury in multiple autoimmune responses. The detection of autoantibodies has been widely used, which promoted the clinical practice of MN toward personalized precision medicine. However, given the potential risks of immunosuppressive therapy, more autoantibodies and biomarkers need to be identified to predict the prognosis and therapeutic response of MN more accurately. In this review, we attempted to summarize the autoantigens/autoantibodies and autoimmune mechanisms that can predict disease states based on the current understanding of MN pathogenesis, especially the podocyte injury manifestations. In conclusion, both the autoimmune response and podocyte injury require multidimensional attention in the disease course of MN.

Membranous nephropathy

Membranous nephropathy (MN) is a glomerular disease that can occur at all ages. In adults, it is the most frequent cause of nephrotic syndrome. In ~80% of patients, there is no underlying cause of MN (primary MN) and the remaining cases are associated with medications or other diseases such as systemic lupus erythematosus, hepatitis virus infection or malignancies. MN is an autoimmune disease characterized by a thickening of the glomerular capillary walls due to immune complex deposition. Identification of the phospholipase A2 receptor (PLA2R) as the major antigen in adults in 2009 induced a paradigm shift in disease diagnosis and monitoring and several other antigens have since been characterized. Disease outcome is difficult to predict and around one-third of patients will undergo spontaneous remission. In those at high risk of progression, immunosuppressive therapy with cyclophosphamide plus corticosteroids has substantially reduced the need for kidney replacement therapy. Owing to carcinogenic risk, other treatments (calcineurin inhibitors and CD20-targeted B cell depletion therapy (rituximab)) have been developed. However, disease relapses are frequent when calcineurin inhibitors are stopped and the remission rate with rituximab is lower than with cyclophosphamide, particularly in patients with high PLA2R antibody titres. Other new drugs are already available and antigen-specific immunotherapies are being developed.

Baseline and early functional immune response is associated with subsequent clinical outcomes of PD-1 inhibition therapy in metastatic melanoma patients

BACKGROUND

Despite significant progress with antiprogrammed cell death protein 1 (PD-1) therapy, a substantial fraction of metastatic melanoma patients show upfront therapy resistance. Biomarkers for outcome are missing and the association of baseline immune function and clinical outcome remains to be determined. We assessed the in vitro nonspecific stimulation of immune response at baseline and during anti-PD-1 therapy for metastatic melanoma.

METHODS

Previously untreated metastatic melanoma patients received nivolumab and radiotherapy as part of the multicentric phase II trial NIRVANA (NCT02799901). The levels of Th1, Th2 and Th17 cytokines on in vitro non-specific stimulation of innate and adaptive immune cells were measured in patient sera before treatment, and at week 2 and week 6 after the beginning of the treatment, and correlated with tumorous response, progression-free survival (PFS) and occurrence of immune-related adverse events (irAEs). The results in melanoma patients were compared with those of a cohort of 9 sex and age-matched healthy donors.

RESULTS

Seventeen patients were enrolled in this ancillary study. Median follow-up was 16 months (2.2-28.4). The 12-month PFS rate was 67.7%. The incidence of irAEs of any grade was 58.8%. Without in vitro stimulation no differences in cytokines levels were observed between responders and non-responders. On in vitro stimulation, metastatic patients had lower Th1 cytokine levels than healthy donors at baseline for tumor necrosis factor-α and interferon-γ (IFN-γ) (1136 pg/mL vs 5558 pg/mL, p<0.0001; and 3894 pg/mL vs 17 129 pg/mL, p=0.02, respectively). Responders exhibited increasing cytokine levels from baseline to week 6. Non-responders had lower interleukin 17A (IL-17A) levels at baseline than responders (7 pg/mL vs 32 pg/mL, p=0.03), and lower IFN-γ levels at week 6 (3.3 ng/mL vs 14.5 ng/mL, p=0.03). A lower level of IL-17A at week 2 and a lower level of IFN-γ at week 6 correlated with worse PFS (p=0.04 and p=0.04 respectively). At baseline, patients who developed irAEs had higher IL-6 levels (19.3 ng/mL vs 9.2 ng/mL, p=0.03) and higher IL-17A levels (52.5 pg/mL vs 2.5 pg/mL, p=0.009) than those without irAEs.

CONCLUSIONS

Our findings indicate that cytokine levels after in vitro non-specific stimulation could be a promising biomarker to predict the outcome of PD-1 inhibition therapy.

Helper T Cells in Idiopathic Membranous Nephropathy

Idiopathic membranous nephropathy (IMN) is an autoimmune disease in which the immune system produces an antibody response to its own antigens due to impaired immune tolerance. Although antibodies are derived from plasma cells differentiated by B cells, the T-B cells also contribute a lot to the immune system. In particular, the subsets of helper T (Th) cells, including the dominant subsets such as Th2, Th17, and follicular helper T (Tfh) cells and the inferior subsets such as regulatory T (Treg) cells, shape the immune imbalance of IMN and promote the incidence and development of autoimmune responses. After reviewing the physiological knowledge of various subpopulations of Th cells and combining the existing studies on Th cells in IMN, the role model of Th cells in IMN was explained in this review. Finally, the existing clinical treatment regimens for IMN were reviewed, and the importance of the therapy for Th cells was highlighted.

[Vaccination against COVID-19 in patients with solid cancer: Review and point of view from a French oncology inter-group (CGO, TNCD, UNICANCER)]

The COVID-19 pandemic has a major impact at all stages of cancer treatment. Risk of death from COVID-19 in patients treated for a cancer is high. COVID-19 vaccines represent a major issue to decrease the rate of severe forms of the COVID-19 cases and to maintain a normal cancer care. It is difficult to define the target population for vaccination due to the limited data available and the lack of vaccine doses available. It appears theoretically important to vaccinate patients with active cancer treatment or treated since less than three years, as well as their family circle. In France, patients actually defined at "high risk" for priority access to vaccination are those with a cancer treated by chemotherapy. A panel of experts recently defined another "very high-priority" population, which includes patients with curative or palliative first or second-line chemotherapy, as well as patients requiring surgery or radiotherapy involving a large lung volume, lymph nodes and/or of hematopoietic tissue. Ideally, it is best to vaccinate before cancer treatment. Despite the lack of published data, COVID-19 vaccines can also be performed during chemotherapy by avoiding periods of bone marrow aplasia and if possible, to do it in cancer care centers. It is necessary to implement cohorts with immunological and clinical monitoring of vaccinated cancer patients. To conclude, considering the current state of knowledge, the benefit-risk ratio strongly favours COVID-19 vaccination of all cancer patients.

Perspectives in membranous nephropathy

The identification of the phospholipase A2 receptor 1 (PLA2R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) as podocyte antigens in adult patients with membranous nephropathy (MN) has strongly impacted both experimental and clinical research on this disease. Evidence has been furnished that podocyte-directed autoantibodies can cause MN, and novel PLA2R- and THSD7A-specific animal models have been developed. Today, measurement of serum autoantibody levels and staining of kidney biopsies for the target antigens guides MN diagnosis and treatment worldwide. Additionally, anti-PLA2R antibodies have been proven to be valuable prognostic biomarkers in MN. Despite these impressive advances, a variety of questions regarding the disease pathomechanisms, clinical use of antibody measurement, and future treatments remain unanswered. In this review, we will outline recent advances made in the field of MN and discuss open questions and perspectives with a focus on novel antigen identification, mechanisms of podocyte injury, clinical use of antibody measurement to guide diagnosis and treatment, and the potential of innovative, pathogenesis-based treatment strategies.

Primary membranous nephropathy in the era of autoantibodies and biological therapies

Primary membranous nephropathy is an autoimmune kidney disease and the most common cause of nephrotic syndrome in adults. About 70%-80% of cases are caused by anti-PLA2R antibodies. Its association with anti-THSD7A antibodies and other autoantibodies has also been described. Recent pilot studies and clinical trials have shown that several biological agents targeting autoantibody-producing cells are effective in controlling the disease with an acceptable safety profile. In this narrative review, we update key concepts about the pathogenesis, autoantibody-based diagnosis, and kidney biopsy findings in primary membranous nephropathy. In addition, we propose a diagnostic and therapeutic algorithm, including guidance on monitoring the response to therapy. We compare the efficacy and safety of currently available treatments, including rituximab and new biological agents, and identify unmet clinical needs.

Proteinuria as a Biomarker for COVID-19 Severity

Background

Renal involvement in syndrome coronavirus 2 (SARS-CoV-2) infection has been retrospectively described, especially acute kidney injury (AKI). However, quantitative proteinuria assessment and its implication in coronavirus disease 2019 (COVID-19) remain unknown.

Methods

In this prospective, multicenter study in France, we collected clinical and biological data including urinary protein to creatine ratio (UPCR) in patients presenting with moderate to severe COVID-19. Clinical outcome was analyzed according to the level of UPCR.

Results

42/45 patients (93.3%) had renal involvement (abnormal urinary sediment and/or AKI). Significant proteinuria occurred in 60% of patients. Urine protein electrophoresis showed tubular protein excretion in 83.8% of patients with proteinuria. Inflammatory parametersand D-dimer concentrations correlated with proteinuria level. Patients who required intensive care unit (ICU) admission had higher proteinuria (p = 0.008). On multivariate analysis, proteinuria greater than 0.3 g/g was related to a higher prevalence of ICU admission [OR = 4.72, IC95 (1.16–23.21), p = 0.03], acute respiratory distress syndrome (ARDS) [OR = 6.89, IC95 (1.41–53.01, p = 0.02)], nosocomial infections [OR = 3.75, IC95 (1.11–13.55), p = 0.03], longer inpatient hospital stay (p = 0.003).

Conclusion

Renal involvement is common in moderate to severe SARS-CoV-2 infection. Proteinuria at baseline is an independent risk factor for increased hospitalization duration and ICU admission in patients with COVID-19.