Phospholipase A2 Receptor Antibody Research Articles

Predictive value of the domain specific PLA2R antibodies for clinical remission in patients with primary membranous nephropathy: A retrospective study.

M-type phospholipase A2 receptor (PLA2R) is a major auto-antigen of primary membranous nephropathy(PMN). Anti-PLA2R antibody levels are closely associated with disease severity and therapeutic effectiveness. Analysis of PLA2R antigen epitope reactivity may have a greater predictive value for remission compared with total PLA2R-antibody level. This study aims to elucidate the relationship between domain-specific antibody levels and clinical outcomes of PMN. This retrospective analysis included 87 patients with PLA2R-associated PMN. Among them, 40 and 47 were treated with rituximab (RTX) and cyclophosphamide (CTX) regimen, respectively. The quantitative detection of -immunoglobulin G (IgG)/-IgG4 targeting PLA2R and its epitope levels in the serum of patients with PMN were obtained through time-resolved fluorescence immunoassays and served as biomarkers in evaluating the treatment effectiveness. A predictive PMN remission possibility nomogram was developed using multivariate logistic regression analysis. Discrimination in the prediction model was assessed using the area under the receiver operating characteristic curve (AUC-ROC).Bootstrap ROC was used to evaluate the performance of the prediction model. After a 6-month treatment period, the remission rates of proteinuria, including complete remission and partial remission in the RTX and CTX groups, were 70% and 70.21% (P = 0.983), respectively. However, there was a significant difference in immunological remission in the PLA2R-IgG4 between the RTX and CTX groups (21.43% vs. 61.90%, P = 0.019). Furthermore, we found differences in PLA2R-CysR-IgG4(P = 0.030), PLA2R-CTLD1-IgG4(P = 0.005), PLA2R-CTLD678-IgG4(P = 0.003), and epitope spreading (P = 0.023) between responders and non-responders in the CTX group. Multivariate logistic analysis showed that higher levels of urinary protein (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.26-0.95; P = 0.035) and higher levels of PLA2R-CTLD1-IgG4 (OR, 0.79; 95%CI,0.62-0.99; P = 0.041) were independent risk factors for early remission. A multivariate model for estimating the possibility of early remission in patients with PMN is presented as a nomogram. The AUC-ROC of our model was 0.721 (95%CI, 0.601-0.840), in consistency with the results obtained with internal validation, for which the AUC-ROC was 0.711 (95%CI, 0.587-0.824), thus, demonstrating robustness. Cyclophosphamide can induce immunological remission earlier than rituximab at the span of 6 months. The PLA2R-CTLD1-IgG4 has a better predict value than total PLA2R-IgG for remission of proteinuria at the 6th month.

An Updated Review of Membranous Nephropathy.

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor (PLA2R) as a target antigen has led to a paradigm shift in the understanding and management of MN. At present, serum PLA2R antibodies are used for diagnosis, prognostication, and guiding treatment. Now, with the discovery of more than 20 novel target antigens, antigen mapping is almost complete. The clinical association of certain antigens provides clues for clinicians, such as the association of nerve epidermal growth factor-like 1 with malignancies and indigenous medicines. Serum antibodies are detected for most target antigens, except exostosin 1 and 2 and transforming growth factor-beta receptor 3, but their clinical utility is yet to be defined. Genome-wide association studies and studies investigating environmental factors, such as air pollution, shed more light on the underpinnings of MN. The standard therapy of MN diversified from cyclical cyclophosphamide and steroids to include rituximab and calcineurin inhibitors over the past decades. Here, we provide a cutting-edge review of MN, focusing on genetics, immune system and environmental factors, novel target antigens and their clinical characteristics, and currently available and emerging novel therapies in MN.

Combined Serologic and Genetic Risk Score and Prognostication of Phospholipase A2 receptor-Associated Membranous Nephropathy.

The aim of this study was to test whether a combined risk score on the basis of genetic risk and serology can improve the prediction of kidney failure in phospholipase A2 receptor (PLA2R)-associated primary membranous nephropathy. We performed a retrospective analysis of 519 biopsy-proven PLA2R-associated primary membranous nephropathy patients with baseline eGFR ≥25 ml/min per 1.73 m 2 . The combined risk score was calculated by combining the genetic risk score with PLA2R ELISA antibody titers. The primary end point was kidney disease progression defined as a 50% reduction in eGFR or kidney failure. Cox proportional hazard regression analysis and C-statistics were applied to compare the performance of PLA2R antibody, genetic risk score, and combined risk score, as compared with clinical factors alone, in predicting primary outcomes. The median age was 56 years (range, 15-82 years); the male-to-female ratio was 1:0.6, the median eGFR at biopsy was 99 ml/min per 1.73 m 2 (range: 26-167 ml/min per 1.73 m 2 ), and the median proteinuria was 5.3 g/24 hours (range: 1.5-25.8 g/24 hours). During a median follow-up of 67 (5-200) months, 66 (13%) had kidney disease progression. In Cox proportional hazard regression models, PLA2R antibody titers, genetic risk score, and combined risk score were all individually associated with kidney disease progression with and without adjustments for age, sex, proteinuria, eGFR, and tubulointerstitial lesions. The best-performing clinical model to predict kidney disease progression included age, eGFR, proteinuria, serum albumin, diabetes, and tubulointerstitial lesions (C-statistic 0.76 [0.69-0.82], adjusted R 2 0.51). Although the addition of PLA2R antibody titer improved the performance of this model (C-statistic: 0.78 [0.72-0.84], adjusted R 2 0.61), replacing PLA2R antibody with the combined risk score improved the model further (C-statistic: 0.82 [0.77-0.87], adjusted R 2 0.69, difference of C-statistics with clinical model=0.06 [0.03-0.10], P < 0.001; difference of C-statistics with clinical-serologic model=0.04 [0.01-0.06], P < 0.001). In patients with PLA2R-associated membranous nephropathy, the combined risk score incorporating inherited risk alleles and PLA2R antibody enhanced the prediction of kidney disease progression compared with PLA2R serology and clinical factors alone.

PLA2R-positive membranous nephropathy in IgG4-related disease

BackgroundIgG4-related disease (IgG4-RD) is a fibroinflammatory disease that affects multiple organs, including the pancreas, lacrimal glands, salivary glands, periaortic/retroperitoneum, and kidney. Interstitial nephritis is a typical renal disorder associated with IgG4-RD, but membranous nephropathy is also seen in some cases.Case presentationHerein we report on the case of a 77-year-old male patient with nephrotic syndrome and IgG4-related lung disease. His serum phospholipase A2 receptor (PLA2R) antibody was positive. His renal biopsy specimen was also positive for PLA2R.The renal biopsy specimen showed membranous nephropathy with equal IgG3 and IgG4 immunofluorescence staining and no interstitial nephritis, suggesting IgG4-RD manifesting as membranous nephropathy.ConclusionsNephrotic syndrome caused by membranous nephropathy is sometimes associated with IgG4-RD. In such cases, even if serum PLA2R antibody is positive, it should be considered that the membranous nephropathy may be secondary to IgG4-RD.

Diagnostic value of renal biopsy in anti-phospholipase A2 receptor antibody-positive patients with proteinuria in China

Renal biopsy remains the gold standard for diagnosing membranous nephropathy (MN). Recent studies have suggested that renal biopsy can be replaced with the serum phospholipase A2 receptor (PLA2R) antibody test for MN diagnosis in patients with nephrotic syndrome. However, this test has not been validated in the Chinese population. In this study, we investigated whether renal biopsy provides additional diagnostic information on patients with proteinuria who are seropositive for PLA2R antibodies (SAb +). We retrospectively reviewed the clinicopathological characteristics of SAb + adult patients (aged ≥ 18 years) with proteinuria (≥ 0.5 g/24 h) assessed at the Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, from June 2021 to March 2022. Among a total of 801 SAb + patients who received renal biopsy, those with incomplete pathological data, diabetes or any potential cause of secondary MN were excluded. Among the 491 remaining patients, 474 had primary MN (PMN), 16 had atypical MN (AMN, 9 patients with “full house” and 2 patients with HBsAg + /HBcAg + immunofluorescence results), and 1 had focal segmental glomerulosclerosis. In patients with an eGFR of ≥ 60 mL/min/1.73 m2 (n = 451), 436 had PMN, and 71 (16.3%) exhibited additional biopsy findings, with obesity-related glomerulopathy being the most common. In patients with an impaired eGFR (n = 40), 38 had PMN, and 31 (81.6%) showed additional findings, with acute tubular injury being the most common. In conclusion, anti-PLA2R antibody positivity is highly predictive of PMN in Chinese adults but often coexists with other pathological diagnoses. The advantages of renal biopsy for detecting other pathologies should be weighed against the potential risks of the biopsy procedure.

Clinical Observation of Serum Anti-PLA2R Antibody Levels in the Treatment of Idiopathic Membranous Nephropathy with Rituximab

Objective: To investigate the efficacy of rituximab in the treatment of idiopathic membranous nephropathy with varying levels of serum phospholipase A2 receptor antibodies. Methods: A total of 137 patients with idiopathic membranous nephropathy admitted to Beijing Sixth Hospital were selected. Based on their blood PLA2R antibody levels before rituximab treatment, patients were categorized into the PLA2R antibody positive group (n = 94) and the PLA2R antibody negative group (n = 43). They were followed up for at least 1 year, during which the efficacy, measured through 24-hour urine protein quantification and serum albumin levels, were compared between the two groups before and after treatment. Results: After 3 months of treatment, there was no significant difference in the quantitative levels of 24-hour urine protein between the two groups (P &gt; 0.05). However, after 6 and 12 months of treatment, there was a significant difference in the levels of 24-hour urine protein between the two groups (P &lt; 0.05). Additionally, after 3 months of treatment, there was a notable difference in the serum albumin levels between the two groups (P &lt; 0.05). However, after 6 and 12 months of treatment, there was no significant difference in serum albumin levels between the two groups (P &gt; 0.05). Analysis of complications in the two groups revealed that in the positive group, 9 individuals experienced thrombosis, 5 had infections, and 11 developed acute kidney injury (AKI). In contrast, in the negative group, 5 individuals had thrombosis, 2 had infections, and 3 developed AKI. There was no statistically significant difference in complications between the two groups (P &gt; 0.05). Conclusion: Serum anti-PLA2R antibody levels provide valuable insights into the clinical observation of rituximab treatment for idiopathic membranous nephropathy. They aid in understanding the disease’s pathogenesis, evaluating treatment efficacy, and predicting disease prognosis.

Clinicopathological characteristics and outcomes of PLA2R related idiopathic membranous nephropathy in patients with seronegative PLA2R antibodies

Background Idiopathic membranous nephropathy (IMN) with deposits of phospholipase A2 receptor (PLA2R) antigen in glomerular tissue (GAg+) but no circulating serum PLA2R antibody (SAb−) has been reported. However, little is known about the clinicopathological characteristics and prognosis of this subtype. Methods A total of 74 IMN patients with GAg + identified by kidney biopsy were enrolled in this study. We categorized patients into two groups based on the presence or absence of serum PLA2R antibody. Data on clinical features, pathological features, and outcomes were collected. Kaplan–Meier analysis of complete remission (CR) and partial remission (PR) comparing SAb−/GAg + and SAb+/GAg + patients. Cox proportional hazards models was used to examine factors associated with CR and PR. Results Among 74 IMN patients, 14 were SAb−/GAg+. Compared with SAb+/GAg + patients, SAb−/GAg + patients presented with higher levels of albumin, lower levels of cholesterol and low density lipoprotein cholesterol (all p < .01), but similar pathological manifestations of kidney biopsy. Multivariate logistic analyses indicated that low albumin (0.79 [95%CI: 0.66–0.95], p = .01) and high cholesterol (1.81 [95%CI: 1.02–3.19], p = .04) were correlated with seropositivity of PLA2R antibody. SAb−/GAg + patients exhibited a significantly higher probability of CR (p = .03) than patients who were SAb+/GAg+. However, no difference was found in the PR rate. Cox regression analyses showed that compared to SAb+/GAg + patients, SAb−/GAg + was more predictive of complete remission (4.28 [95%CI: 1.01–18.17], p = .04). Conclusion IMN with PLA2R staining on kidney biopsy but without serum PLA2R antibody has milder clinical manifestations and a better prognosis.

Clinicopathological and prognostic characteristics of idiopathic membranous nephropathy with dual antigen positivity.

Idiopathic membranous nephropathy (IMN) is the most common pathological type in adults with nephrotic syndrome. Many target antigens have been discovered. However, dual antigen-positive IMN patients are very rare, with only a few such cases being briefly described in various studies. There is no specific study on the clinicopathological and prognostic characteristics of dual antigen-positive IMN patients, and the disease characteristics of such patients remain unclear. Immunohistochemical staining of PLA2R, THSD7A, and NELL-1 was conducted on kidney tissue samples obtained from patients diagnosed with IMN. Simultaneously, the presence of corresponding serum antibodies was determined. Patients exhibiting positivity for dual antigens were included in the study, identified either through tissue staining or serum antibody detection. We retrospectively collected their clinical, pathological, and follow-up data and measured their serum antibody levels at multiple time points. Additionally, the same type of dual antigen-positive IMN cases reported in the literature were reviewed to extract clinical, pathological, and prognostic information. We compared the data for all of the above dual antigen-positive and PLA2R single-positive IMN cases at our center. We identified 6 IMN patients with dual antigen positivity at our center, approximately 0.7% of whole MN series; the previous literature reports 43 IMN patients with dual antigen positivity, the proportion ranged from 0.2% to 2.8%. The IgG1 positivity rate in the renal tissue of the dual antigen-positive patients at our center was significantly lower than that of dual antigen-positive patients previously reported (16.7% vs. 100.0%, p=0.015), but there was no significant difference in clinical or prognostic aspects. Patients with dual antigen positivity reported at our center and in the literature were combined and compared with PLA2R single-positive IMN reported at our center. Compared with PLA2R single-positive IMN patients, dual antigen-positive IMN patients had a higher renal tissue IgG1 positivity rate (58.3% vs. 22.3%, p=0.016), and the time required to achieve remission was longer [13.5 (3.3,35.0) vs. 3.0 (1.0,8.0), p=0.052]. Overall, The changes in urine protein were consistent with the changes in serum PLA2R antibody levels in dual antigen-positive IMN patients. For patients with primary membranous nephropathy who did not attain remission following prolonged treatment, multiple target antigen staining should still be actively performed, even with positivity for the PLA2R target antigen.

The Role of Renal PLA2R Staining Combined with Serum PLA2R Antibody in Membranous Nephropathy Risk Stratification.

This study aimed to examine the clinicopathological profiles and prognosis of membranous nephropathy in different subtypes classified by serum PLA2R antibody (SAb) and glomerular PLA2R antigen staining (GAg). A total of 372 biopsy-proven membranous nephropathy (MN) cases, unrelated to lupus, with urine protein > 2 g/24 h and eGFR > 25 mL/min/1.73 m2 were included and categorized into four groups according to the presence or absence of PLA2R antibody and glomerular PLA2R antigen staining. Clinical profiles were compared among four subtypes. Treatment response and renal outcomes were compared among four groups with primary MN. Cox and logistic regression models were used to examine the association between time-to-renal progression and early remission within 6 months in the four subgroups with primary MN. MN patients who were SAb-/GAg+ presented with a more severe disease onset, whereas those who were SAb-/GAg- had a mild clinical manifestation with a higher prevalence of MN-associated secondary causes. During a median follow-up of 79.2 months (IQR: 48.70-97.40), SAb+/GAg- was identified as an independent risk factor for renal progression [HR: 9.17, 95% CI: 2.26-37.16, p < 0.01] and early remission [OR: 0.06, 95% CI: 0.01-0.56, p = 0.01] in primary MN. Additionally, SAb-/GAg- with primary MN showed an independent association with spontaneous remission after adjusting for age, sex, baseline proteinuria, and eGFR (Before adjustment: OR: 8.33, 95% CI: 1.89-36.76, p = 0.0; after adjustment: OR: 12.25, 95% CI: 2.48-60.53, p < 0.01). Our findings indicated that SAb+/GAg-MN patients exhibited a more severe disease onset and had a poorer prognosis, necessitating an aggressive treatment approach. On the other hand, in the SAb-/GAg- group, the elimination of secondary causes should be considered, and a watchful waiting approach may be appropriate.

Rare coexistence of spinal muscular atrophy with membranous nephropathy - A clinical conundrum with management dilemma.

A 48-year-old male presented with proximal muscle weakness of the shoulder with difficulty in lifting objects above the shoulder in July 2012. Electromyogram was suggestive of chronic motor axonal loss with a myogenic pattern, and a deltoid muscle biopsy revealed groups of atrophic muscle fibers and hypertrophic fibers with pan fascicular atrophy suggestive of adult-onset spinal muscular atrophy. He was managed conservatively and developed bilateral pedal edema in August 2022. He had nephrotic range proteinuria, and renal biopsy revealed capillary wall thickening of glomeruli with serum PLA2R antibody positivity suggestive of primary membranous nephropathy. He was managed with telmisartan for 6 months, and there was a reduction in proteinuria. In January 2023, he was given Injection Rituximab due to worsening proteinuria. He failed to have a clinical resolution. This case report describes the management dilemma in membranous nephropathy with SMA due to the risk of toxic myopathies associated with tacrolimus and steroids.

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

BackgroundPatients 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. MethodsIn 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. ResultsTwenty 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). ConclusionsThe PLA2R antibody was a risk predictor for thromboembolic events in patients with primary membranous nephropathy with serum albumin >25g/l.

The High-Throughput Approach Identifies Compounds that Block PLA2R and Anti-PLA2R Antibody Interaction

The High-Throughput Approach Identifies Compounds that Block PLA2R and Anti-PLA2R Antibody Interaction

The application of podocyte antigen PLA2R and anti-PLA2R antibody in the diagnosis and treatment of membranous nephropathy

Background The application of podocyte antigen M-type phospholipase A2 receptor (PLA2R, GAg) and serum anti-PLA2R antibody (SAb) in predicting the prognosis of membrane nephropathy (MN) was controversial. Method 328 biopsy-proven MN patients were divided into three phenotypes, 182 MN patients with GAg+/SAb+, 118 MN patients with GAg+/SAb-, and 28 MN patients with GAg-/SAb-. The baseline clinicopathological characteristics, therapy response, and prognosis were compared among the three groups. Cox regression analysis was performed to assess predictors of remission. Anti-PLA2R antibody was analyzed by receiver operating characteristic curve to find the optimal titer for MN diagnosis. Result Lower eGFR (p = 0.009), higher UPCR (p < 0.001), and lower serum albumin (p < 0.001) were observed in GAg+/SAb+ MN patients, compared to GAg+/SAb- MN patients. More GAg+/SAb+ MN patients received cyclophosphamide (CTX) combined with glucocorticoids and calcineurin inhibitors (CNI) based therapy than the other two groups (p = 0.015 and p = 0.023, respectively). No significant difference was observed among the three groups in terms of complete remission, relapse, and developing ESRD. SAb+ status was an independent predictor for no remission (hazard ratio 1.378, 95% confidence interval 1.023 to 1.855; p = 0.035). The optimal cutoff value for anti-PLA2R antibody to predict MN was 2.055 RU/mL (sensibility 0.802, specificity 0.970). Conclusion GAg+/SAb+ MN patients were related to more severe clinical manifestations and more requisition of immunosuppressive treatment. Positive anti-PLA2R antibody was an independent predictor for no remission. An anti-PLA2R antibody above 2.055 RU/mL can be a suggestive indicator of MN diagnosis in patients with proteinuria.

A nomogram prediction model for treatment failure in primary membranous nephropathy

Background Primary membranous nephropathy (PMN) has a heterogeneous natural course. Immunosuppressive therapy is recommended for PMN patients at moderate or high risk of renal function deterioration. Prediction models for the treatment failure of PMN have rarely been reported. Methods This study retrospectively studied patients diagnosed as PMN by renal biopsy at Sichuan Provincial People’s Hospital from January 2017 to December 2020. Information on clinical characteristics, laboratory test results, pathological examination, and treatment was collected. The outcome was treatment failure, defined as the lack of complete or partial remission at the end of 12 months. Simple logistic regression was used to identify candidate predictive variables. Forced-entry stepwise multivariable logistic regression was used to develop the prediction model, and performance was evaluated using C-statistic, calibration plot, and decision curve analysis. Internal validation was performed by bootstrapping. Results In total, 310 patients were recruited for this study. 116 patients achieved the outcome. Forced-entry stepwise multivariable logistic regression indicated that PLA2Rab titer (OR = 1.002, 95% CI: 1.001–1.004, p = 0.003), inflammatory cells infiltration (OR = 2.753, 95% CI: 1.468–5.370, p = 0.002) and C3 deposition on immunofluorescence (OR = 0.217, 95% CI: 0.041–0.964, p = 0.049) were the three independent risk factors for treatment failure of PMN. The final prediction model had a C-statistic (95% CI) of 0.653 (0.590–0.717) and a net benefit of 23%-77%. Conclusions PLA2R antibody, renal interstitial inflammation infiltration, and C3 deposition on immunofluorescence were the three independent risk factors for treatment failure in PMN. Our prediction model might help identify patients at risk of treatment failure; however, the performance awaits improvement.

Development and External Validation of a Nomogram for Predicting the Effect of RTX on the Treatment of Membranous Nephropathy.

Rituximab (RTX) has been shown to be effective in inducing immunological remission in patients with membranous nephropathy (MN). Some patients required more than one course of RTX to achieve immunological remission. Identifying patients who need more courses of RTX to achieve immunological remission is beneficial for better physician-patient communication, the assessment of treatment course, and the evaluation of medical costs. This study aims to establish a practical model to predict the probability of immunological remission after receiving one cycle of RTX. This study enrolled 106 patients from the First Affiliated Hospital of Zhengzhou University in the modeling group and 30 patients from Henan Provincial Hospital of Traditional Chinese Medicine in the external validation group. Patients in the modeling group were divided into responders or nonresponders according to whether they achieved immunological remission or not after following up for 6 months. A nomogram was established based on the results of logistic regression analysis. The predictive performance of the nomogram was evaluated by the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCAs). In the modeling group, 75 (70.8%) patients achieved immunological remission within 6 months after receiving one cycle of RTX. Significant differences were observed between nonresponders and responders. Risk factors used in nomogram included PLA2R antibody, hemoglobin, and gender. The AUC value of nomogram was 0.797 (95% CI 0.701-0.894, P<0.001). The calibration curves demonstrated acceptable agreement between the predicted outcomes by the nomogram and the actual values. DCA curves showed good positive net benefits in the predictive model. The external validation also demonstrated the reliability of the prediction nomogram. A predictive nomogram including PLA2R antibody, hemoglobin, and gender may provide a basis to predict the doses of RTX needed in MN patients.

First case report of PLA2R-related monotypic (IgG-κ positive) membranous nephropathy concurrent with leukocyte chemotactic factor 2 amyloidosis

BackgroundMembranous nephropathy (MN) is a major pattern of nephrotic syndrome (NS) in adults. Some MN have secondary causes and some may be accompanied with other glomerular diseases. MN patients coexisting with amyloidosis are very rare, and mostly was polytypic MN. Herein, we describe the first report which identifying monotype PLA2R-MN (κ light chain) concurrent with leukocyte chemotactic factor 2 amyloidosis (ALECT2). This rare case highlights the importance of renal pathology for diagnosis.Case presentationWe describe a case of a 60-year-old male patient with persistent proteinuria and low serum albumin for nine months. No monoclonal component was revealed by serum and urine immunofixation electrophoresis but serum PLA2R antibody was positive. The patient was empirically treated with Leflunomide and Losartan, but edema was not improved. The diagnosis of renal pathology is PLA2R-related monotypic (IgG-κ positive) MN concurrent with ALECT2. Methylprednisolone, cyclosporine A and anticoagulant (rivaroxaban) were prescribed resulting in a complete remission of NS.ConclusionsMN patients concurrent with ALECT2 presented massive proteinuria or NS. When nephrotic range proteinuria is present in ALECT2, it is important to consider that it may be due to a concomitant underlying nephropathy especially MN and treated according to MN will get good therapeutic effect.

Novel Antigens and Clinical Updates in Membranous Nephropathy.

Membranous nephropathy (MN), an autoimmune kidney disease and leading cause of nephrotic syndrome, leads to kidney failure in up to one-third of affected individuals. Most MN cases are due to an autoimmune reaction against the phospholipase A2 receptor (PLA2R) located on kidney podocytes. Serum PLA2R antibody quantification is now part of routine clinical practice because antibody titers correlate with disease activity and treatment response. Recent advances in target antigen detection have led to the discovery of more than 20 other podocyte antigens, yet the clinical impact of additional antigen detection remains unknown and is under active investigation. Here we review recent findings and hypothesize how current research will inform future care of patients with MN.

Comparison of performance and clinical utility of different methods for detecting anti-PLA2R antibody

ObjectivesThis study aimed to compare the performance of enzyme-linked immunosorbent assay (ELISA) and magnetic particle chemiluminescence immunoassay (MP-CLIA) for detecting anti-phospholipase A2 receptor (PLA2R) antibody and their clinical significance in idiopathic membranous nephropathy (IMN) patients. MethodsSerum samples from 448 patients with different types of nephropathy, including 222 with IMN, were tested using both methods. Sensitivity, specificity, and prognostic significance of PLA2R antibody levels were evaluated. ResultsSimilar sensitivity and specificity of ELISA and MP-CLIA in identifying IMN patients was found. However, MP-CLIA performed better than ELISA in predicting the prognosis of IMN patients. Adjusting the cutoff value reduced the false-negative rate in both methods. Logistic regression analysis identified six variables, including MP-CLIA-PLA2R levels, eGFR, lymphocyte count, B lymphocyte count, NK cell count, and complement 4, as predictors of renal function outcomes in IMN patients. ConclusionsBoth ELISA and MP-CLIA are reliable methods for detecting anti-PLA2R antibodies in IMN patients. However, MP-CLIA is more accurate in predicting the prognosis of IMN. Combining MP-CLIA-PLA2R with other variables can help predict renal function outcomes in IMN patients. Our study emphasizes the importance of considering both analytical performance and clinical utility when selecting a PLA2R antibody assay kit.

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

BackgroundPatients 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. MethodsIn 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. ResultsTwenty 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). ConclusionsThe PLA2R antibody was a risk predictor for thromboembolic events in patients with primary membranous nephropathy with serum albumin >25g/l.

Colquhounia root tablet in the treatment of idiopathic membranous nephropathy with subnephrotic proteinuria.

Idiopathic membranous nephropathy (IMN) is the most frequent global cause of nephrotic syndrome in non-diabetic people. In clinical practice, An effective and mild treatment for IMN patients with subnephrotic proteinuria has been adopted. Colquhounia root tablet (CRT) is a traditional Chinese medicine that is widely used in China to treat glomerulopathies. In this study, the effectiveness and safety of CRT in the treatment of IMN with subnephrotic proteinuria have been determined by reviewing the clinical records of 44 patients with IMN. Retrospective analysis of IMN patients with subnephrotic proteinuria treated with CRT in combination with ACEI/ARB or ACEI/ARB alone. The remission rate (complete or partial remission) was the main outcome observed, and proteinuria, estimated glomerular filtration rate (eGFR), serum albumin levels, and adverse effects were the secondary outcomes. This clinical trial included 44 patients, and the overall remission rates at months 6, 9, and 12 after treatment were 68.2% versus 27.3% (p = 0.016), 72.7% versus 36.4% (p = 0.015), and 77.3% versus 36.4% (p = 0.006) in the treatment and control groups, respectively. The application of CRT treatment was an independent predictor of proteinuria remission (p = 0.024). In addition, in patients who were positive for phospholipase A2 receptor (PLA2R) antibodies, the overall remission rate was higher in the treatment group than in the control group after 9months of treatment (75% versus 23.08%, p = 0.017). This retrospective study illustrates that, based on supportive therapy, CRT could be effective in the treatment of IMN with subnephrotic proteinuria with a good safety profile at the same time.