Seropositive PLA2R-associated membranous nephropathy but biopsy-negative PLA2R staining

Author(s):  
Jiao Luo ◽  
Wang Zhang ◽  
Cailing Su ◽  
Zhanmei Zhou ◽  
Guobao Wang

Abstract Background Serum phospholipase A2 receptor (PLA2R) antibody (SAb) and glomerular deposits of PLA2R antigen (GAg) have been tested widely in idiopathic membranous nephropathy (MN). Recently, we noticed a special form of PLA2R-associated MN with positive circulating PLA2R antibody but negative PLA2R deposits in the glomeruli by immunofluorescence on frozen tissue (IF-F). The significance of this form of PLA2R-associated MN is yet to be elucidated. This study aimed to explore the clinicopathological features of these PLA2R-associated MN patients. Methods This study enrolled 229 biopsy-proven PLA2R-associated MN patients with SAb+. SAb was measured by enzyme-linked immunosorbent assay, and GAg was detected by IF-F. These patients were divided into SAb+/GAg+ and SAb+/GAg− groups. Clinicopathological characteristics of SAb+/GAg+ and SAb+/GAg− PLA2R-associated MN patients were compared. PLA2R antigens of 19 SAb+/GAg− PLA2R-associated MN patients were verified by immunohistochemistry on paraffin tissue (IHC-P). Results Among 229 SAb+ PLA2R-associated MN patients, 210 (91.70%) were GAg+ and 19 (8.3%) were GAg−. These 19 SAb+/GAg− PLA2R-associated MN patients presented positive PLA2R deposits by IHC-P. Compared with SAb+/GAg+ PLA2R-associated MN patients, SAb+/GAg- PLA2R-associated MN patients had higher levels of serum PLA2R antibody (P = 0.004), increased proteinuria (P = 0.008), lower serum albumin (P = 0.019), more prominent chronic pathological lesions in terms of glomerulosclerosis score (P = 0.025), interstitial fibrosis score (P = 0.016), tubular atrophy score (P = 0.010) and total renal chronicity score (P = 0.010), and were more likely to be accompanied by focal segmental glomerulosclerosis (P = 0.014). Higher SAb level was associated with the total renal chronicity score (odds ratio per 100 RU/mL, 1.16; 95% confidence interval 1.01–1.33; P = 0.033). Conclusions PLA2R-associated MN patients with seropositive PLA2R antibody but negative PLA2R deposits in the glomeruli by IF-F have higher levels of SAb and worse clinicopathological manifestations compared with their double-positive counterparts. IHC-P can be an alternative technique to reveal PLA2R glomerular deposits.

Author(s):  
Guoqin Wang ◽  
Lijun Sun ◽  
Hongrui Dong ◽  
Yanyan Wang ◽  
Xiaoyi Xu ◽  
...  

Background and objectivesThe 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, & measurementsA 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.ResultsAmong 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).ConclusionsAbout 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.


2019 ◽  
Vol 34 (4) ◽  
pp. 406-413
Author(s):  
Dan Zhang ◽  
Chong Zhang ◽  
Fan Bian ◽  
Wenzhu Zhang ◽  
Gengru Jiang ◽  
...  

Background: Membranous nephropathy is the most common glomerular disease related to malignancy. However, it is difficult to distinguish between true malignancy-related membranous nephropathy and idiopathic membranous nephropathy coincident with cancer. It has been reported that phospholipase A2 receptor (PLA2R) is the first autoantigen involved in idiopathic membranous nephropathy and thrombospondin type-1 domain-containing 7A (THSD7A) may have a close relationship with malignancy-related membranous nephropathy. Therefore, the aim of this study was to compare the clinicopathological characteristics between membranous nephropathy patients with cancer and idiopathic membranous nephropathy patients without cancer to better detect malignancy-related membranous nephropathy, including glomerular PLA2R and THSD7A depositions and their circulating antibodies, together with glomerular IgG4 deposition. Methods: Twelve membranous nephropathy patients with cancer and 257 idiopathic membranous nephropathy patients without cancer were included in this study and had been followed up for more than 1 year. The glomerular expression of PLA2R, THSD7A, and IgG4 was analyzed by immunohistochemistry. Circulating anti-PLA2R and anti-THSD7A antibodies were assessed by enzyme-linked immunosorbent assay and indirect immunofluorescence testing, respectively. Results: Membranous nephropathy patients with cancer were significantly older and had higher serum creatinine and a lower estimated glomerular filtration rate than idiopathic membranous nephropathy patients ( P<0.05). The positive rates of glomerular PLA2R and IgG4 depositions and circulating anti-PLA2R antibodies in membranous nephropathy patients with cancer were significantly lower than those in idiopathic membranous nephropathy patients without cancer ( P<0.01). Conclusion: The absence of glomerular PLA2R deposition and negative circulating anti-PLA2R antibodies, along with negative glomerular IgG4 staining, may be useful clues to more accurately screen underlying malignancies in membranous nephropathy patients.


2021 ◽  
pp. ASN.2020081181 ◽  
Author(s):  
Aishwarya Ravindran ◽  
Marta Casal Moura ◽  
Fernando C. Fervenza ◽  
Samih H. Nasr ◽  
Mariam P. Alexander ◽  
...  

BackgroundIn patients with secondary (autoimmune) membranous nephropathy, two novel proteins, Exostosin 1 and Exostosin 2 (EXT1/EXT2), are potential disease antigens, biomarkers, or both. In this study, we validate the EXT1/EXT2 findings in a large cohort of membranous lupus nephritis.MethodsWe conducted a retrospective cohort study of patients with membranous lupus nephritis, and performed immunohistochemistry studies on the kidney biopsy specimens against EXT1 and EXT2. Clinicopathologic features and outcomes of EXT1/EXT2-positive versus EXT1/EXT2-negative patients were compared.ResultsOur study cohort included 374 biopsy-proven membranous lupus nephritis cases, of which 122 (32.6%) were EXT1/EXT2-positive and 252 (67.4%) were EXT1/EXT2-negative. EXT1/EXT2-positive patients were significantly younger (P=0.01), had significantly lower serum creatinine levels (P=0.02), were significantly more likely to present with proteinuria ≥3.5 g/24 h (P=0.009), and had significantly less chronicity features (glomerulosclerosis, P=0.001 or interstitial fibrosis and tubular atrophy, P<0.001) on kidney biopsy. Clinical follow-up data were available for 160 patients, of which 64 (40%) biopsy results were EXT1/EXT2-positive and 96 (60%) were EXT1/EXT2-negative. The proportion of patients with class 3/4 lupus nephritis coexisting with membranous lupus nephritis was not different between the EXT1/EXT2-positive and EXT1/EXT2-negative groups (25.0% versus 32.3%; P=0.32). The patients who were EXT1/EXT2-negative evolved to ESKD faster and more frequently compared with EXT1/EXT2-positive patients (18.8% versus 3.1%; P=0.003).ConclusionsThe prevalence of EXT1/EXT2 positivity was 32.6% in our cohort of membranous lupus nephritis. Compared with EXT1/EXT2-negative membranous lupus nephritis, EXT1/EXT2-positive disease appears to represent a subgroup with favorable kidney biopsy findings with respect to chronicity indices. Cases of membranous lupus nephritis that are EXT1/EXT2-negative are more likely to progress to ESKD compared with those that are EXT1/EXT2-positive.


Author(s):  
Yu Ho Lee ◽  
Ki Pyo Kim ◽  
Sun-Hwa Park ◽  
Dong-Jin Kim ◽  
Yang-Gyun Kim ◽  
...  

Abstract Background Interstitial fibrosis and tubular atrophy (IFTA) is a well-recognized risk factor for poor renal outcome in patients with diabetic kidney disease (DKD). However, a noninvasive biomarker for IFTA is currently lacking. The purpose of this study was to identify urinary markers of IFTA and to determine their clinical relevance as predictors of renal prognosis. Methods Seventy patients with biopsy-proven isolated DKD were enrolled in this study. We measured multiple urinary inflammatory cytokines and chemokines by multiplex enzyme-linked immunosorbent assay in these patients and evaluated their association with various pathologic features and renal outcomes. Results Patients enrolled in this study exhibited advanced DKD at the time of renal biopsy, characterized by moderate to severe renal dysfunction [mean estimated glomerular filtration rate (eGFR) 36.1 mL/min/1.73 m2] and heavy proteinuria (mean urinary protein:creatinine ratio 7.8 g/g creatinine). Clinicopathologic analysis revealed that higher IFTA scores were associated with worse baseline eGFR (P < 0.001) and poor renal outcome (P = 0.002), whereas glomerular injury scores were not. Among measured urinary inflammatory markers, C-X-C motif ligand 16 (CXCL16) and endostatin showed strong correlations with IFTA scores (P = 0.001 and P < 0.001, respectively), and patients with higher levels of urinary CXCL16 and/or endostatin experienced significantly rapid renal progression compared with other patients (P < 0.001). Finally, increased urinary CXCL16 and endostatin were independent risk factors for poor renal outcome after multivariate adjustments (95% confidence interval 1.070–3.455, P = 0.029). Conclusions Urinary CXCL16 and endostatin could reflect the degree of IFTA and serve as biomarkers of renal outcome in patients with advanced DKD.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Cristina Rabasco ◽  
Ana Martínez ◽  
Rosa Ortega ◽  
Mario Espinosa

Abstract Background and Aims Membranous nephropathy (MN) is the most common cause of biopsied nephrotic syndrome in adults. Recently, it has been reported that the pathogenesis of MN may be associated with an activation of the complement system. The pathway of activation is not clearly established. The intensity of C3 deposition could be a good marker of this activation in MN as has been shown in other diseases (IgA nephropathy, crescentic GN). The aim of this study is to evaluate clinical-pathological data in a cohort of patients with MN and the significance of glomerular C3 staining as a possible predictor of renal outcomes. Method We analysed patients with idiopathic MN biopsied in our department between January 2000 and December 2019, excluding those who had no material for IF (n = 115). The patients were divided into positive (87 cases) and negative (28 cases) based on glomerular C3 deposition. We assessed the clinical and histological characteristics and the percentage of spontaneous remission (SR) and end-stage renal disease (ESRD). Results A total of 115 patients with MN were followed with a median follow-up of 65 (25-161) months. We found no differences in baseline characteristics between both groups, with the exception that patients with C3 deposit had less albumin at the time of biopsy that negative patients [2.4 (2-2.9) vs 2.8 (2.3-3.1) g/dl, P=0.011)]. Patients with C3-negative had a higher percentage of SR than patients with C3-positive (75 vs 24%, P = 0.000) and less need for immunosuppressive treatment (18 vs 56%, P =0.001). At the most recent follow-up, C3-positive group had higher creatinine [1.42 (0.8-1.7) vs 0.97 (0.71-1) mg/dl, P=0.045] and proteinuria [1.64 (0.08-3.2) vs. 0.62 (0.05-0.79) g / 24h, P = 0.039]. Regarding histology, we found no differences in glomerular sclerosis, tubular atrophy and interstitial fibrosis. The renal survival analysis showed no statistically significant differences between both groups (P = 0.091). We analysed a subgroup of patients (n = 23) with antibodies against the phospholipase receptor on blood at the time of the biopsy (13/23 were positive). 84% of this positive group presented C3-positive in the renal biopsy vs 25% of the C3-negative group (P =0.008). Conclusion Patients without C3 staining show a higher rate of SR and less need for immunosuppressive treatment than patients with C3-positive. These results would support the theory that complement activation in this entity can play an important role. It is possible that these patients with negative C3 deposit represent a MN with evolution to SR and in these patients and that these patients do not need immunosuppressive treatment.


2016 ◽  
Vol 44 (6) ◽  
pp. 481-492 ◽  
Author(s):  
Jin Ho Hwang ◽  
Jung Pyo Lee ◽  
Clara Tammy Kim ◽  
Seung Hee Yang ◽  
Jin Hyuk Kim ◽  
...  

Background: Periostin is a matricellular protein and plays a vital role in tissue regeneration, fibrosis and wound healing. However, data about its significance in nephrology are limited. We investigated the correlation between urinary periostin excretion and its clinical significance including renal histologic findings and prognosis in IgA nephropathy (IgAN). Methods: Of 399 patients from a glomerulonephritis cohort recruited between January 2009 and December 2014, 314 were enrolled. Serum and urine periostin (uPOSTN) were measured using enzyme-linked immunosorbent assay. We divided the patients into 3 groups by uPOSTN/creatinine (uPOSTN/Cr): group 1 (undetectable), group 2 (lower than the median) and group 3 (higher than the median). Results: The uPOSTN level was correlated with pathologic classifications and both initial and final IDMS-MDRD estimated glomerular filtration rates (eGFRs; p < 0.001). Histologically, group 3 patients were correlated with severe interstitial fibrosis/tubular atrophy (p = 0.004), interstitial inflammation (p = 0.007), hyaline arteriolosclerosis (p = 0.001) and glomerular sclerosis (p < 0.001). A higher initial uPOSTN/Cr level was associated with a greater decline in eGFR during follow-up (p = 0.043 when initial eGFR ≥60; p = 0.025 when eGFR <60 ml/min/1.73 m2), and the renal outcomes with end-stage renal disease (ESRD; p = 0.003), ESRD and/or eGFR decrease of >30% (p = 0.033) and ESRD and/or eGFR decrease of >50% (p = 0.046) occurred significantly more in group 3. In multivariate analysis, uPOSTN group 3 (hazards ratio 2.839, 95% CI 1.013-7.957; p = 0.047) was independently associated with ESRD in IgAN patients. Conclusion: uPOSTN/Cr value at initial diagnosis correlated with renal fibrosis and predicted the renal outcomes in patients with IgAN. It could be a promising urinary biomarker for renal fibrosis.


2015 ◽  
Vol 42 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Yang Gyun Kim ◽  
Young-Wook Choi ◽  
Se-Yun Kim ◽  
Ju Young Moon ◽  
Chun-Gyoo Ihm ◽  
...  

Background: Anti-phospholipase A2 receptor antibody (PLA2R-Ab) is useful in diagnosing idiopathic membranous nephropathy (IMN). We investigated the clinical relevance of PLA2R-Ab enzyme-linked immunosorbent assay (ELISA) in patients with IMN. Methods: We measured PLA2R-Ab with an ELISA kit from the serum of 160 patients with IMN (n = 93), secondary MN (n = 14) and other glomerulonephritis (n = 41) as well as healthy controls (n = 12) at the time of renal biopsy and investigated the correlation of titers of PLA2R-Ab with clinical parameters. Results: PLA2R-Ab was positive in 41 of 93 patients (44.1%) with IMN. No samples from the patients with secondary MN and other glomerulonephritis or healthy controls were positive with the ELISA test. The PLA2R-Ab-positive patients showed severe disease activity and a low remission rate. The PLA2R-Ab titer positively correlated with proteinuria and was negatively associated with renal function and serum albumin. The patients with a high titer of PLA2R-Ab had significantly decreased remission rates. The cumulative probabilities of remission was significantly lower in patients with PLA2R-Ab (p = 0.01) and even so in patients with a high titer of PLA2R-Ab (p = 0.04). When we compared the ELISA titers with Western blot (WB) data of 43 patients who had been enrolled in our previous study, 18 and 30 patients were positive on ELISA (41.9%) and WB (69.8%), respectively. WB and ELISA had a concordance rate of 72.1% and were positively correlated (r = 0.590, p < 0.001). Conclusion: The presence, as well as a high titer, of PLA2R-Ab on ELISA was associated with poor prognosis of IMN. Assessment of PLA2R-Ab with ELISA is an easy and reliable tool for the diagnosis and guidance of therapeutic plans.


Author(s):  
Brunetta Porcelli ◽  
Andrea Guarnieri ◽  
Fabio Ferretti ◽  
Guido Garosi ◽  
Lucia Terzuoli ◽  
...  

Abstract Background Autoantibodies against-phospholipase A2 receptor (PLA2R) are specific markers of idiopathic membranous nephropathy (iMN). Enzyme-linked immunosorbent assay (ELISA) is becoming the preferred method in many laboratories for the determination of anti-PLA2R antibodies, because it provides quantitative results, and is not prone to subjective interpretation, as is the case with indirect immunofluorescence assay. Methods The purpose of our study was to determine the diagnostic performance of serum PLA2R antibodies detected by commercially available ELISA in a large Italian multicenter cohort of patients with biopsy-proven iMN and in patients with other renal diseases, with special focus on evaluating the optimal cut-off value to discriminate positive and negative results. A total of 495 consecutive patients were recruited. Renal biopsies were performed in all patients, and blood samples were taken before the initiation of immunosuppressive treatment. Results According to the clinical diagnosis and to kidney biopsy, 126 patients were diagnosed with iMN and 369 had other non-membranous nephropathies. Anti-PLA2R autoantibodies were detected using a commercial anti-PLA2R ELISA. At a cut-off value of 20 relative units (RU)/ml indicated by the manufacturer for positive classification, sensitivity was 61.1% and specificity 99.7%. At a cut-off value of 14 RU/ml indicated by the manufacturer for borderline results, sensitivity was 63.5% and specificity remained the same (99.7%). At a cut-off of 2.7 RU/ml, selected as the optimal cut-off on the basis of ROC curve analysis, sensitivity was 83.3% and specificity 95.1%. The best overall efficiency of the test was observed at 2.7 RU/ml; however, the highest positive likelihood ratio and diagnostic odds ratio were achieved at 14 RU/ml. A cut-off threshold higher than 14 RU/ml or lower than 2.7 RU/ml entailed worse test performance. Conclusion Depending on the clinical use (early diagnosis or as a support to confirm clinical diagnosis), nephrologists may take advantage of this evidence by choosing the most convenient cut-off. However, renal biopsy remains mandatory for the definitive diagnosis of iMN and for the assessment of disease severity.


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