Clinical usefulness of autoantibodies to M-type phospholipase A2 receptor (PLA2R) for monitoring disease activity in idiopathic membranous nephropathy (IMN)

Rationale and design of the Japanese Biomarkers in Nephrotic Syndrome (J-MARINE) study

INTRODUCTION

Disease subtyping and monitoring are essential for the management of nephrotic syndrome (NS). Although various biomarkers for NS have been reported, their clinical efficacy has not been comprehensively validated in adult Japanese patients.

METHODS

The Japanese Biomarkers in Nephrotic Syndrome (J-MARINE) study is a nationwide, multicenter, and prospective cohort study in Japan, enrolling adult (≥18 years) patients with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), membranoproliferative glomerulonephritis (MPGN), C3 glomerulopathy (C3G), and lupus nephritis (LN). Baseline clinical information and plasma and urine samples will be collected at the time of immunosuppressive therapy initiation or biopsy. Follow-up data and plasma and urine samples will be collected longitudinally based on the designated protocols. Candidate biomarkers will be measured: CD80, cytotoxic T-lymphocyte antigen 4, and soluble urokinase plasminogen activator receptor for MCD and FSGS; anti-phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A antibodies for MN; fragment Ba, C3a, factor I, and properdin for MPGN/C3G; and CD11b, CD16b, and CD163 for LN. Outcomes include complete and partial remission, relapse of proteinuria, a 30% reduction in estimated glomerular filtration rate (eGFR), eGFR decline, and initiation of renal replacement therapy. The diagnostic accuracy and predictive ability for clinical outcomes will be assessed for each biomarker.

RESULTS

From April 2019 to April 2023, 365 patients were enrolled: 145, 21, 138, 10, and 51 cases of MCD, FSGS, MN, MPGN/C3G, and LN, respectively.

CONCLUSION

This study will provide valuable insights into biomarkers for NS and serve as a biorepository for future studies.

Membranous nephropathy-diagnosis and identification of target antigens

Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. MN is characterized by subepithelial accumulation of immune complexes along the glomerular basement membrane. The immune complexes are composed of immunoglobulin G and a target antigen. PLA2R is the target antigen in approximately 60% of MN cases, and MN is traditionally classified as PLA2R-positive or PLA2R-negative MN. Over the last 7 years, additional target antigens have been identified, which have specific disease associations, distinctive clinical and pathologic findings, and therapeutic implications. The newly discovered target antigens include NELL1, EXT1/EXT2, NCAM1, SEMA3B, PCDH7, FAT1, CNTN1, NTNG1, PCSK6 and NDNF. To group all these antigens into a generic 'PLA2R-negative' MN group is imprecise and un-informative. We propose a logical approach for detection of the target antigen which includes (i) currently available serology-based testing to detect anti-PLA2R and anti-THSD7A antibodies; and (ii) kidney biopsy testing to detect the target antigens. Determination of the antigen on kidney biopsy can be done by immunohistochemistry or immunofluorescence studies. Alternatively, laser capture microdissection (LCM) of glomeruli followed by mass spectrometry (MS) can be used to identify a target antigen. LCM/MS has the advantage of being a one-stop test and is particularly useful for detection of rare target antigens. At the current time, while it is possible to detect the newer antigens by immunohistochemistry/immunofluorescence/LCM/MS, serology-based tests to detect serum antibodies to the new antigens are not yet available. It is critical that serology-based tests should be developed not just for accurate diagnosis, but as a guide for treatment. We review the current methodology and propose an algorithm for diagnosis and detection of target antigens in MN that may shape the current practice in the future. Membranous nephropathy (MN) results from accumulation of subepithelial immune complexes along the glomerular basement membrane.PLA2R is the most common target antigen, but newly discovered target antigens have filled the void of PLA2R-negative MN.MN associated with the newly discovered target antigens have distinctive clinical and pathologic findings, treatment and prognostic implications. These include NELL1, EXT1/EXT2, NCAM1, PCDH7, SEMA3B, CNTN1, FAT1, NDNF and PCSK6.Immunohistochemistry/immunofluorescence methodology is currently in use for detecting target antigens in kidney biopsy tissue, although we anticipate laser capture microdissection of glomeruli followed by mass spectrometry will become available soon.Serologic testing is currently available for only detecting antibodies to PLA2R and THSD7A. It is critical that serologic tests become available for detecting antibodies to the newly discovered antigens.

A comparison of chemiluminescent immunoassay and enzyme-linked immunosorbent assay for detecting phospholipase A2 receptor antibody in primary membranous nephropathy

Objective

The accurate detection of phospholipase A2 receptor (PLA2R) autoantibody is crucial in the diagnosis and monitoring of primary membranous nephropathy (pMN). While enzyme-linked immunosorbent assay (ELISA) is the commonly used detection method, its complexity and time-consuming nature pose challenges, especially for small sample sizes. Chemiluminescence immunoassay (CLIA) has emerged as a rapid alternative for clinical immunoassays. This study aims to compare the sensitivity, specificity, and precision of CLIA and ELISA in detecting PLA2R autoantibody.

Method

A total of 145 patients with biopsy-confirmed primary membranous nephropathy and 85 patients with non-membranous nephropathy were enrolled in this comparative study. CLIA and ELISA were employed to test all samples for the presence of PLA2R autoantibodies. Statistical analysis of sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) was performed using SPSS 26.0. The diagnostic value of ELISA and CLIA for pMN was analyzed using the ROC curve, and Correlation analysis was performed using Spearman.

Results

Serum levels of anti-PLA2R antibody in pMN group were significantly higher than those in nMN group(P < 0.05). The accuracy of CLIA for detecting anti-PLA2R antibody was 76.96%, while ELISA showed an accuracy of 74.78%. The sensitivity for CLIA was 64.83%, compared to 60% for ELISA. However, no statistically significant difference was observed between the two methods (P > 0.05). The overall qualitative agreement of anti-PLA2R detection was 93.35% (95% confidence interval[CI] 89.47-96.3). ROC curve analysis showed that AUC of anti-PLA2R antibody detected by ELISA and CLIA were 0.8737 (95% confidence interval [CI] 0.8270-0.9204), 0.8914 (95% confidence interval [CI]0.8495-0.9332), respectively. The Spearman correlation analysis revealed a significant correlation between them(P < 0.05). Notably, CLIA demonstrated a significant time-saving advantage, particularly when the sample size was less than 200, and especially when it was less than 20.

Conclusion

CLIA and ELISA showed similar accuracy and consistency in detecting anti-PLA2R antibody for primary membranous nephropathy. However, CLIA exhibited a significant advantage in terms of automation and time-saving compared to ELISA, particularly for smaller sample sizes. This finding suggests that CLIA has the potential to become a preferred and widely adopted test in the future.

The association of serum anti-PLA2R antibody and glomerular PLA2R antigen staining with clinical manifestations and outcomes in membranous nephropathy

BACKGROUND

Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) was manifested as seropositive for PLA2R antibodies (SAb) and/or glomerular PLA2R antigens' (GAg) deposits. According to the test of SAb and GAg, PLA2R-associated MN can be divided into SAb + /GAg-, SAb-/GAg + , and SAb + /GAg + groups. The clinical characteristics and outcomes of the three groups need to be further evaluated.

METHODS

184 PLA2R-associated MN patients were enrolled. SAb was measured by enzyme-linked immunosorbent assay with a cut-off value of 14 RU/mL. GAg was detected by immunofluorescence using a paraffin section of renal biopsy samples. Clinical characteristics and the decline of eGFR were compared among the 3 groups.

RESULTS

There were 33 SAb + /GAg-, 46 SAb-/GAg +, and 105 SAb + /GAg + PLA2R-associated MN patients reviewed. Clinical characteristics, such as the level of proteinuria, serum albumin, as well as eGFR, were comparable between the SAb + /GAg- and SAb + /GAg + patients. While SAb-/GAg + patients exhibited mild clinical manifestations as evidenced by higher serum albumin (P < 0.001) and lower proteinuria (p = 0.049) compared with SAb + /GAg + patients. After 21.96 ± 7.39 month follow-up, the eGFR decrease was no difference between the SAb + /GAg- and SAb + /GAg + patients. SAb-/GAg + patients had a lower rate of the > 20% eGFR decline as well as a 50% eGFR decline compared with the SAb + /GAg + patients (10.87% vs 30.48%, p = 0.013; 0.00% vs 4.76%, p = 0.324).

CONCLUSIONS

Our study showed that the clinical manifestations of SAb + /Gag- patients were the same as those of double-positive patients, while SAb-/GAg + patients exhibited mild clinical manifestations and slower eGFR decline compared to the double-positive patients.

Serum PLA2R antibody as a predictive biomarker for venous thromboembolism risk in primary membranous nephropathy

BACKGROUND

Patients with nephrotic syndrome are at high risk of venous thromboembolism (VTE), especially for primary membranous nephropathy (PMN). The phospholipase A2 receptor (PLA2R) is a marker of primary membranous nephropathy activity. This study investigated the predictive value of PLA2R antibodies in PMN for VTE.

METHODS

In this retrospective study, we included 97 PMN patients and evaluated the predictive value of serum PLA2R antibodies for VTE risk. Lower extremity venous ultrasound, renal vein ultrasound, or spiral computed tomography pulmonary arteriography were used to assess VTE events. Serum anti-PLA2R antibodies were detected by enzyme-linked immunosorbent assay (ELISA). The risk of VTE was stratified according to serum albumin levels.

RESULTS

Twenty PMN patients (21%) had thromboembolic events. Eight (15%) of patients with serum albumin >25g/l developed VTE, 6 of whom were positive for serum PLA2R antibodies. Positive serum PLA2R antibodies were significantly associated with VTE events in patients with serum albumin >25g/l (p=0.01). Age, sex, blood creatinine, serum albumin, and 24-h urine protein levels were not statistically different between the two groups. Kaplan-Meier analysis using the log-rank test revealed anti-PLA2R positive membranous nephropathy patients had more probability of VTE events than anti-PLA2R negative patients. Univariate Cox proportional hazards analysis revealed that lnPLA2R-Ab is an unfavorable predictor for VTE events in patients with serum albumin >25g/l (hazard ratio (HR) 2.1, p=0.01).

CONCLUSIONS

The PLA2R antibody was a risk predictor for thromboembolic events in patients with primary membranous nephropathy with serum albumin >25g/l.

Serum anti-phospholipase A2 receptor antibody in pathological diagnosis of type 2 diabetes mellitus patients with proteinuria

Patients with diabetes mellitus complicated with proteinuria can be diabetic nephropathy (DN), diabetic complicated with non-diabetic kidney disease (NDKD), or DN with NDKD. Among these membranous nephropathy accounted for a large proportion of DN with NDRD. At present, serum anti-phospholipase A2 receptor (PLA2R) antibody is widely used in the diagnosis and evaluation of therapy in idiopathic membranous nephropathy, our study aimed to investigate the diagnostic significance of anti-PLA2R antibody in type 2 diabetes mellitus (T2DM) patients with proteinuria, providing a method for patients with contraindications of kidney biopsy. Eighty-seven T2DM patients with proteinuria who went on kidney biopsy were divided into the DN group, idiopathic membranous nephropathy (IMN) group, and others group according to their pathological results. In our study, 52.87% and 28.74% of patients were found to have IMN and diabetic nephropathy respectively. The levels of anti-PLA2R antibody, total cholesterol, triglyceride, and estimated glomerular filtration rate (eGFR) were higher in the IMN group, while the prevalence of diabetic retinopathy (DR), systolic blood pressure (SBP) and HbA1c were higher in the DN group. For T2DM patients with proteinuria, anti-PLA2R antibody (AUC = 0.904, 95%CI 0.838-0.970) has a high diagnostic value for IMN. The duration of diabetes (OR = 0.798, P = 0.030), eGFR level (OR = 1.030, P = 0.024), and positive anti-PLA2R antibody (OR = 72.727, P < 0.001) favor the diagnosis of IMN, while DR (OR = 50.234, P < 0.001), SBP (OR = 1.041, P = 0.030), and negative anti-PLA2R antibody (OR = 0.008, P  = 0.001) is beneficial to the diagnosis of DN. Our study found that NDKD is not uncommon in patients with T2DM and proteinuria, and IMN was the main pathological type. Positive anti-PLA2R antibody has a strong accuracy in the diagnosis of IMN in patients with T2DM and proteinuria.

The Prognostic Value of Anti-PLA2R Antibodies Levels in Primary Membranous Nephropathy

Anti-PLA2R antibodies (Ab) are a diagnostic and prognostic biomarker in primary membranous nephropathy (PMN). We assessed the relationship between the levels of anti-PLA2R Ab at diagnosis and different variables related to disease activity and prognosis in a western population of PMN patients. Forty-one patients with positive anti-PLA2R Ab from three nephrology departments in Israel were enrolled. Clinical and laboratory data were collected at diagnosis and after one year of follow-up, including serum anti-PLA2R Ab levels (ELISA) and glomerular PLA2R deposits on biopsy. Univariable statistical analysis and permutation-based ANOVA and ANCOVA tests were performed. The median [(interquartile range (IQR)) age of the patients was 63 [50-71], with 28 (68%) males. At the time of diagnosis, 38 (93%) of the patients had nephrotic range proteinuria, and 19 (46%) had heavy proteinuria (≥8 gr/24 h). The median [IQR] level of anti-PLA2R at diagnosis was 78 [35-183] RU/mL. Anti-PLA2R levels at diagnosis were correlated with 24 h proteinuria, hypoalbuminemia and remission after one year (p = 0.017, p = 0.003 and p = 0.034, respectively). The correlations for 24 h proteinuria and hypoalbuminemia remained significant after adjustment for immunosuppressive treatment (p = 0.003 and p = 0.034, respectively). Higher levels of anti-PLA2R Ab at diagnosis in patients with active PMN from a western population are associated with higher proteinuria, lower serum albumin and remission one year after the diagnosis. This finding supports the prognostic value of anti-PLA2R Ab levels and their possible use in stratifying PMN patients.

A Genetic Risk Score Distinguishes Different Types of Autoantibody-Mediated Membranous Nephropathy

Introduction

Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults and is characterized by detectable autoantibodies against glomerular antigens, most commonly phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type-1 domain containing 7A (THSD7A). In Europeans, genetic variation in at least five loci, PLA2R1, HLA-DRB1, HLA-DQA1, IRF4, and NFKB1, affects the risk of disease. Here, we investigated the genetic risk differences between different autoantibody states.

Methods

1,409 MN individuals were genotyped genome-wide with a dense SNV array. The genetic risk score (GRS) was calculated utilizing the previously identified European MN loci, and results were compared with 4,929 healthy controls and 422 individuals with steroid-sensitive nephrotic syndrome.

Results

GRS was calculated in the 759 MN individuals in whom antibody status was known. The GRS for MN was elevated in the anti-PLA2R1 antibody-positive (N = 372) compared with both the unaffected control (N = 4,929) and anti-THSD7A-positive (N = 31) groups (p < 0.0001 for both comparisons), suggesting that this GRS reflects anti-PLA2R1 MN. Among PLA2R1-positive patients, GRS was inversely correlated with age of disease onset (p = 0.009). Further, the GRS in the dual antibody-negative group (N = 355) was intermediate between controls and the PLA2R1-positive group (p < 0.0001).

Conclusion

We demonstrate that the genetic risk factors for PLA2R1- and THSD7A-antibody-associated MN are different. A higher GRS is associated with younger age of onset of disease. Further, a proportion of antibody-negative MN cases have an elevated GRS similar to PLA2R1-positive disease. This suggests that in some individuals with negative serology the disease is driven by autoimmunity against PLA2R1.

Preliminary study on the efficacy of rituximab in the treatment of idiopathic membranous nephropathy: A single-centre experience

OBJECTIVE

To investigate the efficacy of rituximab in the treatment of idiopathic membranous nephropathy (IMN).

METHODS

A total of 77 patients with IMN diagnosed in both our hospital and other hospitals were included in this study; the patients were divided into two groups: a treatment-naïve group (n = 19) and a refractory/relapsed group (n = 58). The clinical data of the patients, including urine examination, blood test, safety evaluation and efficacy evaluation results, were analysed retrospectively. The changes in clinical biochemical indexes and adverse reactions were compared between the two groups before and after treatment, and the clinical efficacy of rituximab (RTX) in the treatment of primary IMN and refractory recurrent membranous nephropathy was evaluated.

RESULTS

Of the 77 patients included in this study, the average age was 48 years, and there was a male-to-female ratio of 61:16. There were 19 cases in the initial treatment group and 58 cases in the refractory/relapse group. The 24-hour urine protein quantification, cholesterol, B cell count and M-type phospholipase A2 receptor (PLA2R) results in the 77 patients with IMN after treatment were all lower than those before treatment, and the differences were statistically significant (P < 0.05). Serum albumin was higher than before treatment, and the difference was statistically significant (P < 0.05). The total remission rate in the initial and refractory/relapsed treatment groups was 84.21% and 82.76%, respectively. There was no statistical difference in the total remission rate between the two groups (P > 0.05). During treatment, nine patients (11.69%) experienced infusion-related adverse reactions, which were relieved rapidly after symptomatic treatment. The anti-PLA2R antibody titre of the refractory/relapsed group was significantly negatively correlated with serum creatinine (r = -0.187, P = 0.045) and significantly correlated with 24-hour urine protein (r = -0.490, P < 0.001). There was a positive correlation and a significant negative correlation with serum albumin (r = -0.558, P < 0.001).

CONCLUSIONS

Regardless of whether RTX is used as an initial therapy or refractory/relapsed membranous nephropathy, most patients with IMN have complete or partial remission after RTX treatment, with mild adverse reactions.

Membranous nephropathy: Systems biology-based novel mechanism and traditional Chinese medicine therapy

Membranous nephropathy (MN) is a renal-limited non-inflammatory autoimmune disease in the glomerulus, which is the second or third main cause of end-stage kidney diseases in patients with primary glomerulonephritis. Substantial achievements have increased our understanding of the aetiology and pathogenesis of murine and human MN. The identification of nephritogenic autoantibodies against neutral endopeptidase, phospholipase A₂ receptor (PLA₂R) and thrombospondin type-1 domain-containing 7A (THSD7A) antigens provide more specific concept-driven intervention strategies for treatments by specific B cell-targeting monoclonal antibodies to inhibit antibody production and antibody-antigen immune complex deposition. Furthermore, additional antibody specificities for antigens have been discovered, but their pathogenic effects are uncertain. Although anti-PLA₂R and anti-THSD7A antibodies as a diagnostic marker is widely used in MN patients, many questions including autoimmune response development, antigenic epitopes, and podocyte damage signalling pathways remain unresolved. This review describes the current available evidence regarding both established and novel molecular mechanisms based on systems biology approaches (gut microbiota, long non-coding RNAs, metabolite biomarkers and DNA methylation) in MN, with an emphasis on clinical findings. This review further summarizes the applications of traditional Chinese medicines such as Tripterygium wilfordii and Astragalus membranaceus for MN treatment. Lastly, this review considers how the identification of novel antibodies/antigens and unresolved questions and future challenges reveal the pathogenesis of MN.

Anti-phospholipase A2 receptor antibody levels at diagnosis predicts outcome of TAC-based treatment for idiopathic membranous nephropathy patients

Background

Idiopathic membranous nephropathy (iMN) is recognized as an organ-specific autoimmune disease, mainly caused by anti-PLA2R antibody. This study aimed to study between anti-PLA2R antibody level at diagnosis and the response to tacrolimus (TAC)-based treatment in iMN patients.

Methods

This was a retrospective cohort study including 94 kidney biopsy-proven MN patients with positive anti-PLA2R antibody at diagnosis from May 2017 to September 2021 in our center. All iMN patients received the TAC regimen as the initial immunosuppressive therapy. All patients were divided into two groups according to anti-PLA2R antibody titer at diagnosis: high-level group (> 150 RU/ml; n = 42) and low-level group (≤ 150 RU/ml; n = 52). The association between anti-PLA2R antibody levels and clinical outcomes was assessed using the Kaplan–Meier method.

Results

The low density lipoprotein in the high-level group was significantly higher than low-level group at diagnosis, otherwise, serum albumin was significantly lower than low-level group; however, there was no significant difference in creatinine levels between two groups. The remission rates were significantly higher in the low-level group than high-level group after treatment with TAC for 12, 18, or 24 months (all P < 0.05). After 12 months of treatment with TAC, 82.7% of the patients in the low-level group achieved complete remission (CR) or partial remission (PR) (mean, 6.52 ± 0.53 months). However, 38.1% of the patients in high-level group achieved CR or PR (mean, 9.86 ± 0.51 months). Moreover, CR rate at 12 months in the high-level group was only 4.7% (mean, 11.88 ± 0.63 months). The infection frequency in the high-level group (35.6%) was higher than the low-level group (20%) during the TAC treatment, although there was no significant difference (P = 0.065). There were 19% patients who had end-stage kidney disease (ESKD), and 7.1% of patients died of ESKD in the high-level group during the follow-up period.

Conclusion

Anti-PLA2R antibody level above 150 RU/ml at diagnosis can predict a poor treatment response and outcome of TAC treatment in iMN patients, who may not benefit from TAC or other calcineurin inhibitor regimens as the initial treatment.

Sexual dimorphic response to rituximab treatment: A longitudinal observational study in a large cohort of patients with primary membranous nephropathy and persistent nephrotic syndrome

Rituximab is one of the first-line therapies for patients with membranous nephropathy (MN) at high risk of progression towards kidney failure. We investigated whether the response to Rituximab was affected by sex and anti-PLA₂R antibody levels in 204 consecutive patients (148 males and 56 females) with biopsy-proven MN who were referred to the Nephrology Unit of the Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII from March 2001 to October 2016 and managed conservatively for at least 6 months. The primary outcome was a combined endpoint of complete (proteinuria <0.3 g/24 h) or partial (proteinuria <3.0 g/24 h and >50% reduction vs. baseline) remission. Patients gave written informed consent to Rituximab treatment. The study was internally funded. No pharmaceutical company was involved. Anti-PLA₂R antibodies were detectable in 125 patients (61.3%). At multivariable analyses, female gender (p = 0.0198) and lower serum creatinine levels (p = 0.0108) emerged as independent predictors of better outcome (p = 0.0198). The predictive value of proteinuria (p = 0.054) and anti-PLA₂R titer (p = 0.0766) was borderline significant. Over a median (IQR) of 24.8 (12.0–36.0) months, 40 females (71.4%) progressed to the combined endpoint compared with 73 males (49.3%). Anti-PLA₂R titers at baseline [127.6 (35.7-310.8) vs. 110.1 (39.9–226.7) RU/ml] and after Rituximab treatment were similar between the sexes. However, the event rate was significantly higher in females than in males [HR (95%): 2.12 (1.44–3.12), p = 0.0001]. Forty-five of the 62 patients (72.3%) with anti-PLA₂R titer below the median progressed to the combined endpoint versus 35 of the 63 (55.6%) with higher titer [HR (95%): 1.97 (1.26–3.07), p < 0.0029]. The highest probability of progressing to the combined endpoint was observed in females with anti-PLA₂R antibody titer below the median (86.7%), followed by females with anti-PLA₂R antibody titer above the median (83.3%), males with titer below the median (68.1%), and males with titer above the median (44.4%). This trend was statistically significant (p = 0.0023). Similar findings were observed for complete remission (proteinuria <0.3 g/24 h) and after analysis adjustments for baseline serum creatinine. Thus, despite similar immunological features, females were more resilient to renal injury following Rituximab therapy. These findings will hopefully open new avenues to identify the molecular pathways underlying sex-related nephroprotective effects.

GDF-15 and sST-2 act as biomarkers of disease severity but not independent predictors in idiopathic membranous nephropathy

BACKGROUND

We aimed to explore biomarkers of disease severity in idiopathic membranous nephropathy (IMN) and independent predictors of prognosis in IMN.

METHODS

Clinical data were collected from 79 IMN patients. Serum levels of growth differentiation factor-15 (GDF-15) and soluble suppression of tumorigenicity (sST-2) were tested by enzyme-linked immunosorbent assay (ELISA) in IMN patients and subgroups, and correlation analysis was performed. Univariate and multiple logistic regression analyses were performed to identify independent predictors of IMN, and a combined-factors model was constructed. Moreover, the area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the prognostic efficacy.

RESULTS

The levels of GDF-15 were significantly higher in the IMN group and subgroups with low estimated glomerular filtration rate (eGFR) and high 24 hour-urine protein (24 h-UP), whiles sST-2 level was only significantly higher in the IMN group. GDF-15 levels were positively correlated with creatinine (Crea), cystatin C (Cys-C) and 24 h-UP and negatively correlated with GFR and albumin (Alb), while sST-2 levels were positively correlated with Urea and Cys-C and negatively correlated with eGFR. After one year of follow-up, 54 patients had incomplete remission. Serum phospholipase A2 receptor antibody (PLA2R-Ab), Urea, high-density lipoprotein cholesterol (HDL-C) and 24 h-UP but not GDF-15 and sST2 were independent predictors of prognosis in IMN patients, but combined factors showed the best prognostic efficacy.

CONCLUSION

Serum levels of GDF-15 and sST-2 may be potential biomarkers for the severity of IMN, while the combined-factors model is effective for predicting the risk factors of incomplete remission in IMN.

Level of interleukin-35 in patients with idiopathic membranous nephropathy and its predictive value for remission time

Objective

As a member of interleukin-12 family, interleukin-35 (IL-35) plays an important regulatory role in immune response. The relationship between IL-35 and idiopathic membranous nephropathy (IMN) is still unclear, and the purpose of this study is to clarify the relationship between IL-35 and disease activity and remission of IMN.

Methods

This study was a single-center, retrospective study in which all patients were diagnosed with IMN by renal biopsy or aPLA2R titer and treated with Mahuang Fuzi and Shenzhuo Decoction (MFSD). A follow-up was conducted with the endpoint of clinical complete or partial remission (CR+PR). Levels of serum IL-35 were measured and its relationship with IMN remission were analyzed. The regulatory T cell (Treg) and inducible IL-35 producing Tregs (iTR35) in peripheral blood of IMN patients were detected by flow cytometry.

Results

A total of 76 IMN patients (age 51.95 ± 13.29) were followed-up for 18 (12, 24) months. The level of serum IL-35 in all patients increased after treatment, but the degree of increase in remission group was significantly higher than that in no remission (NR) group (117.6% vs 83.7%, P<0.01). The baseline IL-35 level in remission group was higher than that in NR group (174.87 vs.151.87 pg/ml, P=0.016). Cox regression analysis showed that baseline IL-35 level was a independent risk factor for IMN remission (HR 1.081, 95%CI 1.048-1.116, P<0.001). Patients with baseline IL-35 lower than the lower quartile (≤145.49 pg/ml) had an average remission time twice as long as those with baseline IL-35 higher than the upper quartile (> 203.05 pg/ml) (12mon vs. 24mon, P<0.01). The baseline IL-35 can predict the remission time of IMN patients with either aPLA2R positive (AUC=0.673) or negative (AUC=0.745). Analysis of 18 patients with IMN showed that IL-35 level had a higher correlation with iTR35, but not Treg (r=0.613, P<0.05).

Conclusions

The level of IL-35 in patients with IMN showed an increasing trend with the progress of treatment, and the baseline IL-35 could predict the remission time of IMN patients, including those patients with negative aPLA2R. The level of IL-35 is related to the number of iTR35 cells.

Treatment of rituximab in patients with idiopathic membranous nephropathy: a case series and literature review

BACKGROUND/AIMS

Membranous nephropathy (MN) is a major cause of nephrotic syndrome in adults. This study aimed to evaluate the effect of rituximab (RTX) in patients with idiopathic MN (iMN) who have a high risk of progression.

METHODS

We retrospectively analyzed data of 13 patients with iMN, who received RTX treatments from January 2014 to July 2020. RTX was indicated in patients with iMN with severe proteinuria and decreasing estimated glomerular filtration rate (eGFR) in the previous 6 months despite other immunosuppressive therapies.

RESULTS

The patients were predominantly males (n = 11) and with a mean age of 55.3 years; median eGFR, 37.0 mL/min/1.73 m2 (interquartile range [IQR], 26.3 to 66.5); serum albumin level, 2.6 g/dL (IQR, 1.9 to 3.1); and spot urine protein-to-creatinine ratio at baseline, 6.6 g/g (IQR, 5.7 to 12.9). In a median follow-up of 22 months, eight patients (61.5%) achieved complete or partial remission. In responder group (n = 8), median eGFR increased from 31.5 to 61.5 mL/min/1.73 m2 (p = 0.049) and serum albumin level increased from 2.3 to 4.2 g/dL (p = 0.017) from RTX initiation to last follow-up. Antiphospholipase A2 receptor antibody (anti-PLA2R-Ab) was positive in six among seven tested patients, which markedly decreased in the responder group. There were no adverse events after RTX.

CONCLUSION

This study suggests that RTX is a safe and effective treatment option for patients with iMN who have a high risk of progression. Individualized therapy based on anti-PLA2R-Ab titer would be needed for better outcomes.

Idiopathic Membranous Nephropathy with Solitary Immunoglobulin A Deposition: A Case Report and a Review of the Literature

A 63-year-old man with an 8-year history of proteinuria was diagnosed with nephrotic syndrome, and a renal biopsy was performed. Light and electron microscopic analyses showed classic features of idiopathic membranous nephropathy (IMN). However, immunofluorescence tests revealed solitary polyclonal granular IgA deposition along the glomerular capillary walls, rather than IgG, which is often dominant in IMN. The combined use of corticosteroids and calcineurin inhibitor was noticeably effective in reducing proteinuria and improving edema in the current case. Two additional rare cases of IMN with solitary IgA deposition were reviewed, and long-term surveillance is still warranted to characterize its clinicopathological features and outcome.

The Role of Anti-PLA2R and Anti-THSD7A Antibodies in the Pathogenesis and Diagnostics of Primary Membranous Nephropathy: A Review of Current Knowledge for Clinical Practice

Primary membranous nephropathy (PMN) is considered a major cause of nephrotic syndrome. The discovery of circulating autoantibodies directed against glomerular podocytes helped to classify them as autoimmune diseases. Over the past years, there has been an increasing significance of anti-Phospholipase A2 Receptor (anti-PLA₂R), which has been detected in 70–80% of PMN cases, and relevance of anti-Thrombospondin type I domain-containing 7A (anti-THSD7A) even though they are present in 2–5% of patients. The results of clinical and experimental studies indicate that these antibodies are pathogenic. It radically changed the diagnostic and therapeutic approach. Measurement of antibody titers in the serum seems to be a valuable tool for identifying PMN and for the assessment of disease activity. By monitoring pathogenic antibodies levels rather than proteinuria or reduced glomerular filtration rate (GFR) as an indicator of glomerular disease, physicians would easier divide patients into those with active and inactive PMN disease and decide about their therapy. The aim of this review is to evaluate scientific evidence about the role of autoantibodies, namely anti-PLA₂R and anti-THSD7A, as PMN biomarkers. The present manuscript focuses on PMN pathogenesis and key data of diagnosis, monitoring of the disease, and treatment strategies that are currently being used in clinical practice.

Definition of IgG Subclass-Specific Glycopatterns in Idiopathic Membranous Nephropathy: Aberrant IgG Glycoforms in Blood

The podocyte injury, and consequent proteinuria, that characterize the pathology of idiopathic membranous nephropathy (IMN) is mediated by an autoimmune reaction against podocyte antigens. In particular, the activation of pathways leading to abundant renal deposits of complement is likely to involve the binding of mannose-binding lectin (MBL) to aberrant glycans on immunoglobulins. To obtain a landscape of circulatory IgG Fc glycosylation characterizing this disease, we conducted a systematic N-glycan profiling study of IgG1, 2, and 4 by mass spectrometry. The cohort included 57 IMN patients, a pathological control group with nephrotic syndrome (PN) (n = 20), and 88 healthy control subjects. The effect of sex and age was assessed in all groups and controlled by rigorous matching. Several IgG Fc glycan traits were found to be associated with IMN. Interestingly, among them, only IgG4-related results were specific for IMN and not for PN. Hypo-galactosylation of IgG4, already shown for IMN, was observed to occur in the absence of core fucose, in line with a probable increase of pro-inflammatory IgG. In addition, elevated levels of fucosylated IgG4, along with low levels of hybrid-type glycans, were detected. Some of these IgG4 alterations are likely to be more pronounced in high PLA2R (phospholipase A2 receptor) patients. IgG Fc glycosylation patterns associated with IMN warrant further studies of their role in disease mechanisms and may eventually enrich the diagnostic spectrum regarding patient stratification.

Negative anti-phospholipase A2 receptor antibody status at three months predicts remission in primary membranous nephropathy

Background

The value of anti-phospholipase A2 receptor antibody (anti-PLA2R ab) monitoring at 3 months after diagnosis in membranous nephropathy (MN) remains uncertain.

Methods

We retrospectively examined the outcome on 1 August 2020 of 59 adult patients (age 54 (44, 68) years, 69% male, SCr 1.0 (0.9, 1.3) mg/dL) diagnosed with MN (kidney biopsy, positive serum anti-PLA2R ab). The outcomes were: kidney survival; partial and/or complete remission.

Results

Most of the studied patients (97%) received immunosuppression, cyclophosphamide regimens were the most frequent (87%), followed by cyclosporine (10%). The median time to remission was 12.0 months and the cumulative remission rates were 34% at 6, 54% at 12, and 73% at 24 months. Forty (69%) patients had negative anti-PLA2R ab at 3 months, they had similar age, serum creatinine, albumin, proteinuria, and treatment with the group with positive ab at 3 months. In the Cox proportional hazard model, three months anti-PLA2R ab negativization (HR 0.4 (95%CI 0.1, 0.9)) was an independent predictor for remission, while baseline hypoalbuminemia (HR 3.0 (95%CI 1.5, 5.7)) was associated with absence of remission. Six (10%) patients died, mostly due to cardiovascular disease and infections. A total of five (9%) patients started dialysis. Mean kidney survival time was 50.3 months and there was no survival difference in relation to baseline anti-PLA2R ab titer (p .09) or 3 months negativization (p .8).

Conclusions

Three months anti-PLA2R ab negativization seems to be a late predictor of remission, and lower serum albumin at diagnosis is an early marker for remission absence. Abbreviations: anti-P LA2R ab, anti-phospholipase A2 receptor antibody; eGFR, estimated glomerular filtration rate; ESKD, end stage kidney disease; MN, membranous nephropathy; NELL-1, neural epidermal growth factor-like 1 protein; RAAS: renin–angiotensin–aldosterone system; RBC: red blood cells; RRT, renal replacement therapy; T HSD7A, thrombospondin type-1 domain containing 7A

Chinese medicinal herbs for idiopathic membranous nephropathy in adults with nephrotic syndrome: A systematic review of effectiveness and safety

ABSTRACT

To assess the benefits and harms of Chinese medicinal herbs formulae for the treatment of idiopathic membranous nephropathy in adult patients with primary nephrotic syndrome.Only randomized controlled trials were included. We searched the Cochrane Central Register of Controlled Trials database, PubMed, EMBASE, Chinese National Knowledge Internet, Chinese Biomedicine Database, and VIP. All studies were analyzed using the criteria of the Cochrane Handbook and were assessed in terms of quality and the risk of bias. Review Manager ver. 5.3.5 software was used for the data analysis, and GRADE profiler software was employed to evaluate quality.Two studies were included (n = 126 Chinese participants). We found that compared with against conventional treatment, one Chinese medicinal herbs formula plus conventional treatment reduced 24-hours urinary total protein (mean differences -3.16 g/24 h, 95% confidence intervals -4.03 to -2.29), and two Chinese medicinal herbs formulae increased serum albumin levels (mean differences 3.18 g/L, 95% confidence intervals 1.12 to 5.52; I2 = 0%).Chinese medicinal herbs formulae may reduce 24-hours urinary total protein and increase serum levels of albumin. However, larger and multicenter studies with high methodological quality are still needed.

Assessing and counteracting fibrosis is a cornerstone of the treatment of CKD secondary to systemic and renal limited autoimmune disorders

Chronic kidney disease (CKD) is an increasing cause of morbidity and mortality worldwide. Besides the higher prevalence of diabetes, hypertension and aging worldwide, immune mediated disorders remain an important cause of kidney disease and are especially prevalent in young adults. Regardless of the initial insult, final pathway to CKD and kidney failure is always the loss of normal tissue and fibrosis development, in which the dynamic equilibrium between extracellular matrix synthesis and degradation is disturbed, leading to excessive production and accumulation. During fibrosis, a multitude of cell types intervene at different levels, but myofibroblasts and inflammatory cells are considered critical in the process. They exert their effects through different molecular pathways, of which transforming growth factor β (TGF-β) has demonstrated to be of particular importance. Additionally, CKD itself promotes fibrosis due to the accumulation of toxins and hormonal changes, and proteinuria is simultaneously a manifestation of CKD and a specific driver of renal fibrosis. Pathways involved in renal fibrosis and CKD are closely interrelated, and although important advances have been made in our knowledge of them, it is still necessary to translate them into clinical practice. Given the complexity of this process, it is highly likely that its treatment will require a multi-target strategy to control the origin of the damage but also the mechanisms that perpetuate it. Fortunately, rapid technology development over the last years and new available drugs in the nephrologist's armamentarium give reasons for optimism that more personalized assistance for CKD and renal fibrosis will appear in the future.

Kidney injury molecule-1 levels are associated with therapeutic outcomes and renal tubulointerstitial injury severity in idiopathic membranous nephropathy

Kidney injury molecule-1 (KIM-1) has an important role in chronic kidney disease development. The present study aimed to retrospectively analyze patients with idiopathic membranous nephrology (IMN) with different therapeutic outcomes to investigate the association between KIM-1 levels and therapeutic outcomes. A total of 51 patients with IMN and 20 healthy controls were included. Patients were classified into three groups: Spontaneous remission, remission with immunosuppressive therapy (IST) and nonremission with IST. Clinical and biochemical variables were collected. Urinary KIM-1 levels were measured by ELISA and renal KIM-1 expression was evaluated by immunohistochemistry. Patients with IMN were characterized as having elevated urinary and renal KIM-1 levels compared with those in the controls. Significantly increased urinary and renal KIM-1 levels were observed in the nonremission with IST group compared with those in the spontaneous remission group, and the same trend was observed for the plasma anti-podocyte antigen phospholipase A2 receptor antibody levels. Patients with more severe tubular injury (T2 index) presented with significantly higher urinary and renal KIM-1 levels than those with the T0 index. Urinary and renal KIM-1 levels were positively correlated with blood urea nitrogen, serum creatinine, serum cystatin-C, urinary albumin/creatinine ratio, urinary β2-microglobulin and the renal interstitial fibrosis index, and they were negatively correlated with serum albumin. Furthermore, urinary KIM-1 levels were positively correlated with the renal KIM-1 levels. In conclusion, the measurement of urinary and renal KIM-1 levels may be helpful in guiding medication selection and predicting therapeutic outcomes for patients with IMN.

Immunosuppressive Treatments for Idiopathic Membranous Nephropathy: A Pilot Study According to Histopathological Stages

BACKGROUND

No scholar has explored whether immunosuppressive treatments at different histopathological stages are different for idiopathic membranous nephropathy (IMN).

METHODS

From January 1, 2012, to January 1, 2018, all biopsy confirmed IMN cases treated with glucocorticoid (GC) plus cyclophosphamide (CTX) or GC were retrieved from the patients' medical records.

RESULTS

The present study included 67 patients who received GC alone (31 with stage I, 30 with stage II and 6 with stage III) and 157 patients who received GC + CTX (77 with stage I, 66 with stage II and 14 with stage III). Primary efficacy assessments included achieving complete remission and remission. Secondary efficacy assessments included proteinuria, serum albumin and adverse events. GC + CTX group showed higher complete remission rates than the GC group after 6 and 12 months in patients with stage II IMN (22% vs 10%, P = 0.04 and 59% vs 17%, P < 0.001, respectively). However, the two groups showed no difference in stages I and III (29% vs 26%, P = 0.61, 71% vs 52%, P = 0.09 and 14% vs 17%, P = 0.81, 21% vs 17%, P = 0.88, respectively). The GC + CTX group suffered a higher rate of gastrointestinal symptoms than the GC group in stage I and a higher rate of abnormal liver function in stage II.

CONCLUSIONS

Treatment with GC + CTX was more effective than GC in treating patients with stage II IMN; however, the advantage of GC + CTX was not significant for patients with stage I and III IMN.

Serum complement factor B is associated with disease activity and progression of idiopathic membranous nephropathy concomitant with IgA nephropathy

PURPOSE

Few studies have reported the roles of the complement system in concomitant idiopathic membranous nephropathy and IgA nephropathy (IMN-IgAN). Complement factor B (CFB) is a crucial factor that involved in the alternative complement pathway. We aimed to evaluate the association between disease activity (eGFR, anti-PLA2R antibody levels and 24 h urinary protein excretion), progression and serum CFB levels of IMN-IgAN patients.

METHODS

In total, 39 IMN-IgAN patients (median follow-up, 46.6 months), 99 IMN patients and 92 IgAN patients participated in this study. The disease progression event was defined as end-stage renal disease (ESRD) or a 30% decline in estimated glomerular filtration rate (eGFR). The serum CFB concentration was measured by enzyme-linked immunosorbent assay.

RESULTS

Serum CFB levels were lower in IMN-IgAN patients than in patients with IgAN only (P < .001). Serum CFB levels correlated positively with serum creatinine levels, anti-PLA2R antibody levels and 24 h urinary protein excretion (P < .05). Kaplan-Meier analysis revealed that IMN-IgAN patients with high serum CFB levels had a significantly lower cumulative renal survival rate than patients with low levels (log-rank test, P = .009). Multivariate Cox regression analysis showed that high baseline serum CFB levels were significantly associated with poor renal outcome in patients with IMN-IgAN (HR: 2.727, 95% CI 1.076-6.913, P = .034).

CONCLUSION

High serum CFB levels correlated with increased serum creatinine, anti-PLA2R antibody and urinary protein excretion as well as poor renal prognosis in patients with IMN-IgAN, indicating that serum CFB may be a marker of disease activity and progression.

Neural Epidermal Growth Factor-Like 1 Protein-Positive Membranous Nephropathy in Chinese Patients

BACKGROUND AND OBJECTIVES

The neural EGF-like 1 (NELL-1) protein is a novel antigen in primary membranous nephropathy. The prevalence and clinical characteristics of NELL-1-positive membranous nephropathy in Chinese individuals with primary membranous nephropathy are unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 832 consecutive patients with biopsy-proven primary membranous nephropathy were enrolled. The glomerular expression of phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A (THSD7A) was screened. Glomerular immunohistochemistry staining for NELL-1 was performed in 43 patients with PLA2R- and THSD7A-negative membranous nephropathy, 31 patients with PLA2R-positive membranous nephropathy, and two patients with PLA2R and THSD7A double positivity. The NELL-1 antibody was also detected in the sera of patients with NELL-1-positive membranous nephropathy by western blot. Clinical and pathologic features were comparable between patients with isolated NELL-1-positive, isolated PLA2R/THSD7A-positive, and triple antigen-negative membranous nephropathy.

RESULTS

Among the 832 patients with primary membranous nephropathy, 11 of 54 (20%) patients with PLA2R-negative membranous nephropathy had THSD7A-positive membranous nephropathy. NELL-1-positive membranous nephropathy accounted for 35% (15 of 43) of all patients with PLA2R- and THSD7A-negative membranous nephropathy. One patient was double positive for NELL-1 and PLA2R in glomerular deposits and positive for only the PLA2R antibody in the serum. Most patients with NELL-1-positive membranous nephropathy were women. No tumors were found. There were significant differences in the prevalence of IgG subtypes between patients with different antigen positivity. Among patients with isolated NELL-1-positive membranous nephropathy, although 80% (12 of 15) were IgG4 staining positive, the proportion of IgG4 dominance was only 67% (ten of 15).

CONCLUSIONS

About one third of patients who were PLA2R and THSD7A negative were NELL-1 positive in Chinese patients with primary membranous nephropathy. NELL-1-positive membranous nephropathy was more common than THSD7A-positive membranous nephropathy in PLA2R-negative membranous nephropathy.

Anti-PLA2R1 Antibodies as Prognostic Biomarker in Membranous Nephropathy

Introduction

Personalized treatment for patients with membranous nephropathy requires accurate prediction of the disease course at an early stage. In this study, we evaluated the value of baseline anti–phospholipase A2 receptor (PLA2R1) antibody titer as a prognostic biomarker in patients with PLA2R1-associated membranous nephropathy.

Methods

In this cohort study, we included 168 patients (118 men, 50 women) referred to our nephrology center between February 1995 and November 2016. Mean age was 52 ± 13 years. There were 156 patients with new-onset disease and 12 patients with a relapse (n = 10) or recent use of immunosuppressive therapy (n = 2). We measured anti-PLA2R1 titer at baseline and analyzed progression to severe disease (30% increase of serum creatinine or start of immunosuppressive therapy) as a primary study endpoint over 60 months.

Results

There was a clear association between anti-PLA2R1 antibody titer and severity of the nephrotic syndrome. In univariate analysis, anti-PLA2R1 antibody titer was also associated with disease progression. However, in Cox proportional hazard models that included proteinuria and serum creatinine, anti-PLA2R1 antibody titer was no longer associated with clinical outcome. Results were similar when limiting the analysis to the patients with new-onset disease.

Conclusion

Our study questions the relevance of single measurement of anti-PLA2R1 antibodies at baseline as a prognostic biomarker in membranous nephropathy. Future studies are needed to determine the possible role of sequential measurements of anti-PLA2R1 antibodies as a prognostic biomarker of disease progression.

Rituximab in Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of primary nephrotic syndrome among adults. The identification of phospholipase A2 receptor (PLA2R) as target antigen in most patients changed the management of MN dramatically, and provided a rationale for B-cell depleting agents such as rituximab. The efficacy of rituximab in inducing remission has been investigated in several studies, including 3 randomized controlled trials, in which complete and partial remission of proteinuria was achieved in approximately two-thirds of treated patients. Due to its favorable safety profile, rituximab is now considered a first-line treatment option for MN, especially in patients at moderate and high risk of deterioration in kidney function. However, questions remain about how to best use rituximab, including the optimal dosing regimen, a potential need for maintenance therapy, and assessment of long-term safety and efficacy outcomes. In this review, we provide an overview of the current literature and discuss both strengths and limitations of "the new standard."

Membranous Nephropathy: From Research Bench to Personalized Care

Membranous nephropathy is a glomerulopathy that causes nephrotic syndrome and, in at least a third of cases, lasting end-stage kidney disease (ESKD). It is also a rare case of revolutionary changes in our understanding of the disease, that translates from scientific findings to real diagnosis and treatment recommendations in less than ten years. In this review we present: (1) a short history and traditional approach to patients with membranous nephropathy, (2) current recommendations and treatment options that have emerged in recent years, (3) findings of new studies, with a particular focus on serological/immunological methods, genomic and proteomic studies, still requiring validation. With further development in this field, membranous nephropathy may become one of the first nephrological conditions that apply a truly personalized approach with the omission of invasive measures such as kidney biopsy.

PLA2R1 and HLA-DQA1 gene variations in idiopathic membranous nephropathy in South China

INTRODUCTION

Associations of variations in PLA2R1 and HLA-DQA1 genes with susceptibility to idiopathic membranous nephropathy (IMN) have been well documented. Association with spontaneous remission, however, is poorly defined in the Chinese Han population.

METHODS

A Chinese cohort of 117 IMN patients and 138 healthy controls were recruited between July 2009 and November 2019. Case-control studies for single-nucleotide polymorphisms (SNPs) within HLA-DQA1 (rs2187668) and PLA2R1 (rs35771982, rs4664308, rs3749117, rs3749119) genes were performed. The contributions of these polymorphisms to predict susceptibility, titre of autoantibodies against the M-type phospholipase A2 receptor (anti-PLA2R1), glomerular PLA2R1 expression, and spontaneous remission were analysed.

RESULTS

We found that variations in PLA2R1 (SNPs rs35771982, rs4664308, rs3749117) were strongly associated with IMN susceptibility, while SNP (rs2187668) within HLA-DQA1 did not increase the risk of IMN. All SNPs in PLA2R1 and HLA-DQA1 were not statistically associated with anti-PLA2R1 titre, glomerular PLA2R1 expression and spontaneous remission after Bonferroni correction (P>0.0167). Clinical and pathological parameters such as lower levels of serum albumin, higher levels of anti-PLA2R1 and glomerular PLA2R1 expression were independent risk factors for non-spontaneous remission.

CONCLUSION

This study confirms that variations in PLA2R1 (SNPs rs35771982, rs4664308, rs3749117) are risk factors for IMN. We found excellent association of serum albumin level, anti-PLA2R1 titre and glomerular PLA2R1 positivity with non-spontaneous remission in IMN.

The significance of anti-phospholipase receptor antibodies in a patient with membranous nephropathy

Membranous nephropathy (MN) is the major cause of nephrotic syndrome in adults and may be secondary to systemic lupus erythematosus or malignancy in 25% of patients. Without any etiology, it is called primary MN, which is usually associated with phospholipase A2 (PLA2) receptor antibodies. Secondary MN can appear months before a secondary cause is identified. Here, we report a case of MN, that was found to be secondary to pancreatic adenocarcinoma and positive for PLA₂ receptor antibodies.

Detection of urinary podocytes by flow cytometry in idiopathic membranous nephropathy

Idiopathic membranous nephropathy (iMN) is considered an immune-mediated disease where circulating autoantibodies against podocyte targets (mainly the PLA₂R) cause the deposition of in-situ subepithelial immune-complexes. The consequent podocyte damage may cause cell detachment in urine (Podocyturia-PdoU). PdoU has been assessed in different kidney diseases, but limited data are available in iMN. In this study all patients with a diagnosis of iMN between 15/12/1999-16/07/2014 were tested for PLA₂R antibodies (Ab anti-PLA₂R, ELISA kit) and PdoU by flow cytometry with anti-podocalyxin antibody. A semi-quantitative PdoU score was defined according to the percentage of podocalyxin positive cells normalized to the total volume of sample and set relative to the urine creatinine measured in the supernatant. PdoU was positive in 17/27 patients (63%; 1+ score in 6/27-22.2%, 2+ in 4/27-14.8%, 3+ in 2/27-7.4%, 4+ in 5/27-18.5%). Only 2/7 patients with complete remission showed a positive PdoU (1+) while all six patients without remission have significant PdoU. PdoU+ was statistically correlated with the absence of remission and Ab anti-PLA₂R + (p < 0.05) but PdoU, analysed as a continuous variable, showed a non-linear correlation with proteinuria or PLA₂R antibody levels also in the cohort of patients with two available PdoU tests. In conclusion, PdoU could be detected in iMN and seems to be associated with commonly considered markers of disease activity (proteinuria and Ab anti-PLA₂R) with a non-linear correlation. Despite data should be confirmed in large and prospective cohorts, according to the podocyte depletion hypothesis PdoU may represent an early marker of immunological activation with potential prognostic utility.

Idiopathic Membranous Nephropathy: Glomerular Pathological Pattern Caused by Extrarenal Immunity Activity

Idiopathic membranous nephropathy (IMN) is a pathological pattern of glomerular damage caused by an autoimmune response. Immune complex deposition, thickness of glomerular basement membrane, and changes in the podocyte morphology are responsible for the development of proteinuria, which is caused by the targeted binding of auto-antibodies to podocytes. Several auto-antigens have recently been identified in IMN, including M-type receptor for secretory phospholipase A2 (PLA2R1), thrombospondin type-1 domain-containing 7A (THSD7A), and neural epidermal growth factor-like 1 protein (NELL-1). The measurement of peripheral circulating antibodies has become an important clinical reference index. However, some clinical features of IMN remain elusive and need to be further investigated, such as the autoimmunity initiation, IgG4 predominance, spontaneous remission, and the unique glomerular lesion. As these unresolved issues are closely related to clinical practice, we have proposed a hypothetical pathogenesis model of IMN. Induced by environmental stimuli or other causes, the PLA2R1 antigen and/or THSD7A antigen exposed to extrarenal tissues, such as lungs, then produce the auto-antibodies that target and cause damage to the podocytes in circulation. In this review, we highlighted the potential association between environmental stimuli, immune activity, and glomerular lesions, the underlying basis for spontaneous immune and proteinuria remission.

Phospholipase-A2 receptor antibody, 24 hours proteinuria, and serum albumin as indicators of cyclophosphamide efficacy in idiopathic membranous nephropathy

Background

We aimed to evaluate cyclophosphamide efficacy in the treatment of idiopathic membranous nephropathy (IMN) and explore the efficacy of phospholipase‐A2 receptor antibody (PLA2R‐Ab), 24 hours proteinuria, and serum albumin in predicting 6‐ and 12‐month treatment effects.

Methods

A retrospective analysis was performed on 135 patients with IMN who followed up after treatment. The observation points were before, and after 3, 6, and 12 months of treatment. We collected clinical indicator data at each observation point and measured PLA2R‐Ab levels before and after 3‐month treatment.

Results

The remission rates at 3, 6, and 12 months of cyclophosphamide therapy for patients with IMN were 41.4, 74.8, and 76.1%, respectively. Patients in whom PLA2R‐Ab turned negative within 3 months had high remission rates at 3, 6, and 12 months after treatment (P < .05). PLA2R‐Ab change at 3 months had a strong correlation with 24 hours proteinuria change at 6 months. The change in albumin concentration before and after 3‐month treatment was an independent variable related to remission rate at 6 months, and 24 hours proteinuria change before and after 6‐month treatment was an independent variable related to remission rate at 12 months after treatment.

Conclusion

Cyclophosphamide showed good efficacy at 3, 6, and 12 months for patients with IMN. Serum albumin change and PLA2R‐Ab change at 3 months can be used as indicators to predict remission at 6 months, respectively. Moreover, 24 hours proteinuria change at 6 months can predict remission at 12 months.

sPLA2-IB Level Correlates with Hyperlipidemia and the Prognosis of Idiopathic Membranous Nephropathy

Recent studies suggested that serum secretory phospholipase A2 group IB (sPLA2-IB) was increased in idiopathic membranous nephropathy (IMN). However, the interference of high lipemia on the sPLA2-IB levels was not taken into account in these studies. The present study aimed to investigate the correlation between sPLA2-IB and lipemia, and the clinical merit of sPLA2-IB in the prediction of prognosis of IMN patients. A total of 64 IMN patients, 39 immunoglobulin A nephropathy (IgAN) patients and 64 healthy controls were included in the study. The levels of serum sPLA2-IB, lipemia and proteinuria were measured. Fifty IMN patients were followed up for 6 months. Pathologic stages were made for all IgAN and IMN patients. The results showed that the levels of serum sPLA2-IB, cholesterol and low-density lipoprotein cholesterol (LDL-C) were significantly higher, and the levels of albumin and high-density lipoprotein cholesterol (HDL-C) were significantly lower in IMN patients than in healthy controls and IgAN patients. Serum sPLA2-IB levels were also found to be higher in IgAN patients than in heathy controls, but the association of serum sPLA2-IB levels with proteinuria, cholesterol and albumin was only shown in IMN patients. Antibody against M-type receptor for secretory phospholipase A2 (PLA2R1) was positive in 81.3% IMN patients. Glomerular sPLA2-IB deposition, podocyte fused processes, and density deposition on thickened basement membrane were seen in IMN patients, but not in IgAN patients. IMN patients with lower sPLA2-IB and proteinuria levels were found to have better outcome after the 6-month follow-up. In IMN patients, sPLA2-IB levels were significantly increased in both serum and renal tissue. In conclusion, serum sPLA2-IB was closely correlated with proteinuria, albumin and cholesterol, and IMN patients with lower sPLA2-IB levels were more likely to achieve a better outcome.

Long-term renal survival and related risk factors for primary membranous nephropathy in Chinese children: a retrospective analysis of 217 cases

BACKGROUND

Primary membranous nephropathy (PMN) is a rare pathological finding in paediatric patients. Data on PMN in children have been restricted to studies with small samples and fairly short follow-up periods. Therefore, we conducted this single-centre study to evaluate the long-term renal survival and related risk factors for PMN in children, and the clinical and histological characteristics were also described.

METHOD

Two hundred and seventeen children with PMN were enrolled from July 2008 to September 2017. Patients with follow-up durations < 12 months were excluded, except for patients who progressed to end-stage kidney disease (ESKD) or experienced a related death within 12 months. Long-term renal survival and related risk factors were analysed.

RESULT

The sex ratio was 1.33:1 (male vs female), and the median age was 15.0 (14.0-17.0) years old. The most prominent clinical manifestation was nephrotic syndrome (130 59.9%), which was accompanied by various degrees of oedema (142 65.4%), hyperlipidaemia (151 69.6%), hypoalbuminemia (130 59.9%), and nephrotic proteinuria (135 62.2%). Hypertension occurred in 36.4% of children with PMN. After a median follow-up of 45.0 (23.5-74.0) months, 11 patients (5.1%) developed ESKD, and the cumulative kidney survival rates of ESKD at 5 and 10 years after renal biopsy were 95.3% and 67.8%, respectively. The cumulative kidney survival rates of the combined event of ESKD and/or 30% decline in estimated glomerular filtration rate (eGFR) at 5 and 10 years after renal biopsy were 92.6% and 59.5%, respectively. Cox multivariate regression and Kaplan-Meier analysis demonstrated that hypertension and proteinuria ≥ 50 mg/kg/day were associated with renal outcome.

CONCLUSION

In this study, the 5-year and 10-year cumulative renal survival rates of ESKD in children with PMN were reported for the first time as 95.3% and 67.8%, respectively. In addition, this is the first report to find that hypertension and proteinuria  ≥ 50 mg/kg/day are associated with renal outcome in children with PMN.

Membranous nephropathy and thymoma in a patient with ankylosing spondylitis: A case report

RATIONALE

We report a rare case with ankylosing spondylitis (AS), thymoma, and membranous glomerulonephritis. The pathogenic mechanisms of these 3 diseases may be associated with each other. Here, we discuss the course of diagnosis and treatment.

PATIENT CONCERNS

A 64-year-old woman with bilateral pain of the sacroiliac joints for 10 years and anasarca for 10 days.

DIAGNOSES

A diagnosis of AS by HLA-B27 and pelvic X-ray tests, thymoma based on computed tomography and pathological diagnosis, and membranous glomerulonephritis based on renal biopsy.

INTERVENTIONS

We administered methylprednisolone 500 mg/d for 3 consecutive days, followed by methylprednisolone 40 mg oral QD, for a month.

OUTCOMES

The patient was followed up once a month. In the sixth month, the patient's serum creatinine had decreased to 0.96 mg/dL, urine microalbumin/creatinine decreased to 173.3 mg/g, and albumin had risen to 33.1 g/L. Pain and morning stiffness were relieved, and the Bath Ankylosing Spondylitis Disease Activity Index score dropped to 4.0.

LESSONS

Although the causal relationship between AS, thymoma, and membranous nephropathy in this patient still needs to be established, the pathogenesis between the 3 diseases may have some association. In clinical practice, patients with AS need to be screened for tumors and renal complications.

Retrospective study: clinicopathological features and prognosis of idiopathic membranous nephropathy with seronegative anti-phospholipase A2 receptor antibody

Background

To discuss the clinicopathological features and prognosis of patients with idiopathic membranous nephropathy (IMN) who are serum-negative for the anti-PLA2R antibody.

Method

Overall, 229 IMN patients were retrospectively collected in this study and classified into anti-PLA2R antibody-negative (PLA2R−, 59 cases) and antibody-positive (PLA2R+, 170 cases) groups. The clinical and pathological features of the PLA2R− group were analyzed; 162 patients in both groups were followed up, and the PLA2R antigen was detected in renal biopsies from the PLA2R− group. Kaplan-Meier and survival analyses were used to compare differences in prognosis.

Results

Serum albumin levels were higher and 24-hour urine protein, creatinine, and beta 2-microglobulin (BMG) levels were lower in the PLA2R− group than in the PLA2R+ group; the proportion of acute and chronic tubular lesions was also significantly lower in the PLA2R− group than in in the PLA2R+ group. After treatment, the remission rate was significantly higher in the negative group than in the positive group (93.02% vs 74.78%,), especially the rate of complete remission (51.16% vs 23.47%). Furthermore, the PLA2R antigen-positive staining rate of 43 patients in the PLA2R− group was 62.79%. Although not significant, the survival rate was higher in the PLA2R− group than in the PLA2R+ group. BMG, 24-hour urine protein and acute and chronic tubular lesions were risk factors for kidney death, and 24-hour urine protein was an independent risk factor for kidney death.

Conclusions

Compared with the PLA2R+ group, the PLA2R− group had mild clinical manifestations and pathological damage and a higher clinical treatment remission rate. Renal tissue PLA2R antigen testing can be considered for patients with seronegative IMN to increase the diagnostic rate.

Management and treatment of glomerular diseases (part 1): conclusions from a kidney disease: improving global outcomes (KDIGO) controversies conference

The Kidney Disease: Improving Global Outcomes (KDIGO) initiative organized a Controversies Conference on glomerular diseases in November 2017. The conference focused on the 2012 KDIGO guideline with the aim of identifying new insights into nomenclature, pathogenesis, diagnostic work-up, and, in particular, therapy of glomerular diseases since the guideline’s publication. It was the consensus of the group that most guideline recommendations, in particular those dealing with therapy, will need to be revisited by the guideline-updating Work Group. This report covers general management of glomerular disease, IgA nephropathy, and membranous nephropathy.

Management and treatment of glomerular diseases (part 1): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

The Kidney Disease: Improving Global Outcomes (KDIGO) initiative organized a Controversies Conference on glomerular diseases in November 2017. The conference focused on the 2012 KDIGO guideline with the aim of identifying new insights into nomenclature, pathogenesis, diagnostic work-up, and, in particular, therapy of glomerular diseases since the guideline's publication. It was the consensus of the group that most guideline recommendations, in particular those dealing with therapy, will need to be revisited by the guideline-updating Work Group. This report covers general management of glomerular disease, IgA nephropathy, and membranous nephropathy.

Baseline proteinuria level is associated with prognosis in idiopathic membranous nephropathy

Objectives: This study aimed to investigate the unique prognostic, clinical, and renal histopathological characteristics of patients with idiopathic membranous nephropathy (IMN) with different levels of proteinuria.

Methods: This retrospective observational study included 190 IMN patients with low levels of proteinuria (low group), 193 IMN patients with medium levels of proteinuria (medium group), and 123 IMN patients with high levels of proteinuria (high group) treated between September 2006 and November 2015. Prognostic and baseline clinical and histopathological data were compared among the three groups. Poor prognostic events included the occurrence of a persistent 50% reduction in estimated glomerular filtration rate (eGFR), end-stage renal disease, or all-cause mortality.

Results: The severity of clinical symptoms and laboratory indices, such as blood pressure; extent of edema and hematuria; levels of fibrinogen, immunoglobulin (Ig)-G, complement (C)-4, total protein, albumin (ALB), and serum creatinine (SCr); and eGFR increased with increasing proteinuria (all p< .001). Based on renal histopathology, the extent of segmental sclerosis and balloon adhesion and renal interstitial lesion stage also increased in severity with increasing proteinuria (all p< .001). The Kaplan–Meier analysis showed that compared with patients with low and medium levels of proteinuria, patients with high levels of proteinuria had significantly lower cumulative poor event-free renal survival rates (p= .0039).

Conclusions: Baseline proteinuria level is indicative of prognosis in IMN patients; the greater the extent of proteinuria is, the worse the prognosis.

Immune-Monitoring Disease Activity in Primary Membranous Nephropathy

Primary membranous nephropathy (MN) is a glomerular disease mediated by autoreactive antibodies, being the main cause of nephrotic syndrome among adult patients. While the pathogenesis of MN is still controversial, the detection of autoantibodies against two specific glomerular antigens, phospholipase A2 receptor (PLA₂R) and thrombospondin type 1 domain containing 7A (THSD7A), together with the beneficial effect of therapies targeting B cells, have highlighted the main role of autoreactive B cells driving this renal disease. In fact, the detection of PLA₂R-specific IgG4 antibodies has resulted in a paradigm shift regarding the diagnosis as well as a better prediction of the progression and recurrence of primary MN. Nevertheless, some patients do not show remission of the nephrotic syndrome or do rapidly recur after immunosuppression withdrawal, regardless the absence of detectable anti-PLA₂R antibodies, thus highlighting the need of other immune biomarkers for MN risk-stratification. Notably, the exclusive evaluation of circulating antibodies may significantly underestimate the magnitude of the global humoral memory immune response since it may exclude the role of antigen-specific memory B cells. Therefore, the assessment of PLA₂R-specific B-cell immune responses using novel technologies in a functional manner may provide novel insight on the pathogenic mechanisms of B cells triggering MN as well as refine current immune-risk stratification solely based on circulating autoantibodies.

Circulating anti-phospholipase A2 receptor antibodies as a diagnostic and prognostic marker in Greek patients with idiopathic membranous nephropathy – a retrospective cohort study

Introduction . Circulating autoantibodies against phospholipase A2 receptor (anti-PLA2R) are recognized as key elements in the pathogenesis of idiopathic membranous nephropathy. In current clinical practice, they are increasingly gaining attention as novel tools for diagnosis and disease monitoring. We investigated the diagnostic and prognostic utility of anti-PLA2R antibody measurements in Greek patients with biopsy-proven membranous nephropathy.

Methods . Anti-PLA2R levels were measured in serum samples from 33 patients at diagnosis using ELISA and were associated with treatment outcome. Moreover, serial anti-PLA2R measurements were performed in 15 patients under different clinical conditions and level alterations were correlated with disease activity.

Results . Positive anti-PLA2R antibodies at diagnosis were found in 16 of 33 patients (48.5%). Anti-PLA2R levels were independently associated with the achievement of complete remission of nephrotic syndrome after immunosuppressive treatment compared to partial remission (p = 0.02, R2 = 0.265, 95%CI -0.019 to -0.0003). Higher detectable antibody levels at diagnosis were correlated with higher proteinuria levels (r = 0.813, p = 0.0001, 95%CI 0.532 to 0.933) and lower eGFR at the end of follow-up (r = -0.634, p = 0.0083, 95%CI -0.86 to -0.202). Serial antibody measurements during follow-up showed that anti-PLA2R titers were significantly reduced at the end of treatment after complete remission was achieved, remained low under sustained clinical remission, and increased during relapse.

Conclusions . Our findings confirm the usefulness of anti-PLA2R measurements in the diagnosis of idiopathic membranous nephropathy. Low levels of anti-PLA2R antibodies at diagnosis are predictive of complete remission of nephrotic syndrome following immunosuppressive treatment. Serial anti-PLA2R measurements correlate well with clinical status throughout the follow-up period and could be used routinely for monitoring of disease activity and treatment planning.

Combined Plasmatic and Tissue Approach to Membranous Nephropathy-Proposal of a Diagnostic Algorithm Including Immunogold Labelling: Changing the Paradigm of a Serum-based Approach

Membranous nephropathy represents the most frequent cause of nephrotic syndrome in the adult, leading to end-stage renal disease in one third of all the patients. In the last years, the discovery of circulating autoantibodies against phospholipase A2 receptor 1 (PLA2R) and thrombospondin type-1 containing 7A domain (THSD7A), shed light on the pathogenesis of idiopathic forms, being responsible for 70% and 3% of all the cases, respectively. These identifications allowed the development of serological and histologic tests to detect autoantibodies and relative targets for diagnostic and prognostic purposes. Rising evidences suggest that serum titer correlates with disease activity and response to therapy. For these reasons, for patients with nephrotic syndrome, a serum-based approach has been proposed, reserving renal biopsy only in cases with doubtful/negative serology. However, the recent introduction of useful criteria for the interpretation of PLA2R/THSD7A immunohistochemistry could lead to high values of sensitivity and specificity for the in situ detection of target antigens. The present multicentric study on a series of membranous nephropathy cases with available serum/histologic correlation will show the importance of the crosstalk among the different techniques, recovering the possible role of electron microscopy in challenging situations.

Impact of Recent Clinical Trials on Nephrology Practice: Are We in a Stagnant Era?

BACKGROUND

Although renal replacement therapy prevents death from uremia, survival among patients with acute and chronic kidney diseases (CKD) remains an imperative concern. The expected life span of US dialysis patients 60-64 years of age is approximately 4.5 years; this is similar to that of patients with lung cancer. Despite substantial progress in many medical specialties over the past decades (e.g., notable reductions in myocardial infarction, stroke, and mortality rates in the general population), survival among dialysis patients has not improved significantly over the same period. A few decades ago, HIV infection and AIDS were pretty much a death sentence. Because of progress in HIV treatment, now it can be controlled with a daily pill, and ongoing research is pushing treatment even further and controls the virus with longer-acting treatment. A cure is no longer impossible for HIV and other viral infections such as hepatitis B and C and many malignancies, but so far there is no cure for CKD.

SUMMARY

Billions of dollars have been spent on kidney disease research in the past decades, with no tangible progress in clinical practice. The challenges of improving the quantity and quality of trials in nephrology are enormous. The number of randomized controlled trials (RCTs) published in nephrology is lower than that in other medical subspecialties, and most of the big RCTs in nephrology yield negative results. Nephrology studies evaluating hard clinical endpoints or surrogate endpoints are scarce.

KEY MESSAGE

Herein we discuss the slow progress in nephrology research that has impacted clinical practice over the last couple of decades and highlight the major obstacles, challenges, and potential solutions.

Analysis of predictive factors for immunosuppressive response in anti-phospholipase A2 receptor antibody positive membranous nephropathy

BACKGROUND

Serum anti-phospholipase A2 receptor (PLA2R) antibody was correlated with disease activity of membranous nephropathy(MN). The predictive value of antibody titer changes on immunosuppressive response remains unknown. We investigated predictive value of dynamic change of anti-PLA2R antibody and 24-h urine protein (24hUP) for clinical response of MN.

METHODS

This was a retrospective cohort study including 47 Chinese MN patients with positive anti-PLA2R antibody in a tertiary referral hospital between January 2012 and March 2014. Patients received cyclophosphamide (CTX, n = 23), or cyclosporine (CYA, n = 24) regimen, respectively. We monitored serum anti-PLA2R titer and 24hUP at one, three and six-month follow-up.

RESULTS

At baseline, total patients were 42 ± 14 years old with 29/18 male/female ratio. The median 24hUP was 5.80(3.56,9.41) g/d. The median baseline anti-PLA2R antibody titer was 66.4(31.9, 188.0) RU/mL. Baseline 24hUP and eGFR between subgroups were not significantly different. The differences of relative reduction between antibody titer and 24hUP at one month were statistically significant (CTX group 94.2% vs. 46.8%, P < 0.001; CYA group 54.6% vs. 4.6%, P = 0.04). Only in CTX group, the relative reduction of 24hUP at one month was correlated with composite remission at six-month(P = 0.03). Area under the curve of 24hUP relative reduction in CTX group at one-month for predicting composite remission at six months was 0.85(95%CI 0.65~1.05, P = 0.04). The cutoff value of one-month's 24hUP relative reduction for predicting six-month's composite remission in CTX group was 15.3%, with high sensitivity (83.3%) and specificity (100%).

CONCLUSIONS

Compared with relative reduction of antibody titer, relative reduction of 24hUP at one-month follow-up in CTX group had a better predictive value for six-month's composite remission.

HLA class II alleles differing by a single amino acid associate with clinical phenotype and outcome in patients with primary membranous nephropathy

Genome-wide associations and HLA genotyping have revealed associations between HLA alleles and susceptibility to primary membranous nephropathy. However, associations with clinical phenotypes and kidney outcome are poorly defined. We previously identified DRB1*1501 and DRB1*0301 as independent risk alleles for primary membranous nephropathy. Here, we investigated HLA associations with demographic characteristics, anti-phospholipase A2 receptor (PLA2R) antibody, treatment response and kidney outcome after a median follow-up of 52 months in 258 patients. DRB1*0301, but not DRB1*1501, was associated with a significantly higher level of PLA2R antibody (odds ratio 1.58, 95% confidence interval 1.13-2.22). Although DRB1*1502, which differs from DRB1*1501 by a single amino acid, was not a risk allele for primary membranous nephropathy (odds ratio 1.01), it was associated with significantly lower estimated glomerular filtration rates both at baseline (1.79, 1.18-2.72) and at last follow-up (1.72, 1.17-2.53), a significantly worse renal outcome by Kaplan-Meier analysis and a significantly higher risk of end-stage renal disease by Cox regression analysis (hazard ratio 4.52, 1.22-16.74). Nevertheless, the absence of remission remained the only independent risk factor for end-stage renal disease by multivariate analysis. DRB1*1502 was also associated with a significantly higher median PLA2R antibody level [161.4 vs. 36.3 U/mL] and showed interaction with DRB1*0301 for this variable. Thus, HLA genes control PLA2R antibody production and primary membranous nephropathy severity and outcome. Additionally, DRB1*1502 behaves like a modifier gene with a strong predictor value when associated with HLA risk alleles. Other modifier genes need further investigations in larger cohorts.

The prognostic value of phospholipase A2 receptor autoantibodies on spontaneous remission for patients with idiopathic membranous nephropathy: A meta-analysis

BACKGROUND

The presence of antibodies against phospholipase A2 receptor (PLA2R-Abs) in serum at diagnosis is reported to be related to the rate of spontaneous remission in patients with idiopathic membranous nephropathy (IMN); however, there is still lack of enough samples to illustrate this problem. Here, we conducted a comprehensive meta-analysis to investigate the prognostic value of PLA2R-Abs on spontaneous remission for IMN patients in the absence of immunosuppressive therapy.

METHODS

A systematic search of the PubMed, EMBASE, and Cochrane Central databases was performed for relevant original articles published until October 2017. All studies focus on spontaneous remission rates in IMN patients associated with PLA2R-Abs, the endpoint of interest is spontaneous remission rate. Risk ratio (RR) and corresponding 95% confidence intervals (CI) were carried out using a fixed or random effects model. The data were analyzed by Review Manager 5.3 software.

RESULTS

A total of 5 articles involving 190 patients were included in this meta-analysis. There were significant differences between the 2 groups in spontaneous remission rate. The seropositive of PLA2R-Abs measured at the time of diagnosis was negatively correlated with the likelihood of spontaneous remission (RR = 0.69; 95% CI, 0.56-0.87; P = .001).

CONCLUSION

In PLA2R-Abs seronegative patients, the spontaneous remission rate is higher than that of PLA2R-Abs seropositive patients during symptomatic treatment. Therefore, in order to avoid malignant events caused by immunosuppressive therapy, maybe it is more beneficial to adopt conservative treatment for PLA2R-Abs seronegative patients at initial treatment.