Rituximab-induced depletion of anti-PLA2R autoantibodies predicts response in membranous nephropathy.
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SUBMITTER: Beck LH
PROVIDER: S-EPMC3148709 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundCirculating serum autoantibodies against the M-type phospholipase A2 receptor (PLA2R-AB) are a key biomarker in the diagnosis and monitoring of primary membranous nephropathy (MN). However, little is known about the appearance and trajectory of PLA2R-AB before the clinical diagnosis of MN.MethodsUsing the Department of Defense Serum Repository, we analyzed PLA2R-AB in multiple, 1054 longitudinal serum samples collected before diagnosis of MN from 134 individuals with primary MN, 35 individuals with secondary MN, and 134 healthy volunteers. We evaluated the presence and timing of non-nephrotic range proteinuria (NNRP) and serum albumin measurements in relation to PLA2R-AB status.ResultsAnalysis of PLA2R-AB in longitudinal serum samples revealed seropositivity in 44% (59 out of 134) of primary MN cases, 3% (one out of 35) of secondary MN cases, and in 0% of healthy controls. Among patients with MN, PLA2R-AB were detectable at a median of 274 days before renal biopsy diagnosis (interquartile range, 71-821 days). Approximately one third of the participants became seropositive within 3 months of MN diagnosis. Of the 21 individuals with documented prediagnostic NNRP, 43% (nine out of 21) were seropositive before NNRP was first documented and 28.5% (six out of 21) were seropositive at the same time as NNRP; 66% (39 out of 59) of those seropositive for PLA2R-AB had hypoalbuminemia present at the time antibody was initially detected. Twelve participants (20%) were seropositive before hypoalbuminemia became apparent, and eight participants (14%) were seropositive after hypoalbuminemia became apparent.ConclusionsCirculating PLA2R-AB are detectable months to years before documented NNRP and biopsy-proven diagnosis in patients with MN.
| S-EPMC6934991 | biostudies-literature
Project description:BackgroundM-type phospholipase A2 receptor (PLA2R) is known as a major antigen on podocytes, which is involved with the pathogenesis of idiopathic membranous nephropathy (iMN). Many studies have shown that serum anti-PLA2R autoantibodies (sPLA2R) are prevalent in patients with iMN but are rarely detected in secondary membranous nephropathy (SMN) or other glomerulonephritis. The anti-PLA2R is considered as a promising serum biomarker in iMN but reports about its diagnostic value are variable and inconsistent.ObjectiveTo evaluate the diagnostic test accuracy (DTA) of anti-PLA2R and glomerular PLA2R antigen (gPLA2R) for diagnosing iMN.MethodMEDLINE, EMBASE, WEB OF SCIENCE, and COCHRANE LIBRARY were searched from 2009 January to February 2018. Heterogeneity was evaluated by Q test and I2. Source of heterogeneity was explored by subgroup analysis and meta-regression. Meta-analysis was executed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement.ResultsTotally, 35 studies were retrieved under the pre-set study eligibility criteria. Twenty-eight studies were included to evaluate the DTA of anti-PLA2R for differentiating iMN from non-iMN. They indicated a pooled sensitivity of 65% (63-67%), specificity of 97% (97-98%), positive likelihood ratio of 15.65 (9.95-24.62), and negative likelihood ratio of 0.37 (0.32-0.42) with a diagnostic OR (sDOR) of 50.41 (31.56 to 80.52) and AUC of 0.9393. No threshold effect was detected. The heterogeneity analysis for sDOR showed that I2 = 50.3% and Cochran-Q = 54.29, df = 27 (p = 0.0014). Heterogeneity was significant. Meta-regression revealed that sample size might be the potential source of heterogeneity. Subgroup analysis demonstrated that method type and ratio of patients with nephrotic-range proteinuria at baseline might be the source of heterogeneity. Sixteen studies reported the diagnostic value of glomerular PLA2R antigen for differentiating iMN from non-iMN. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, sDOR, and AUC were 79% (76-81%), 90% (88-92%), 8.17 (5.60-11.93), 0.25 (0.19-0.33), 39.37 (22.18-60.13), and 0.9278. Heterogeneity analysis showed that Cochran-Q = 35.36; df = 15 (p = 0.002), and I2 for sDOR was 57.6%.ConclusionsPLA2R and gPLA2R demonstrated a good diagnostic accuracy in differentiating iMN and non-iMN.
| S-EPMC5932148 | biostudies-literature
Project description:Rituximab (RTX) and cyclophosphamide (CYC) based treatments are both recommended as first-line therapies in idiopathic membranous nephropathy (IMN) by KDIGO 2021 guideline. However, the efficacy of RTX vs. CYC-based treatments in IMN is still controversial. We performed this systemic review and meta-analysis registered in PROSPERO (CRD 42,022,355,717) by pooling data from randomized controlled trials or cohort studies in IMN patients using the EMBASE, PubMed, and Cochrane libraries (till Orc 1, 2022). The primary outcomes were the complete remission (CR) rate + partial remission (PR) rate. CR rate, immunologic response rate, relapse rate, and the risk of serious adverse events (SAE) were secondary outcomes. Eight studies involving 600 adult patients with IMN were included with a median follow-up duration of 12 to 60 months. RTX induced a similar overall remission rate compared with CYC (RR 0.88, 95% CI: 0.71, 1.09, P = 0.23). At the follow-up time of 6 months, RTX was associated with a lower CR + PR rate compared with CYC (RR 0.67, 95% CI: 0.52, 0.88, P = 0.003). Moreover, RTX might be less effective in inducing CR + PR than CYC treatment in IMN patients with high antiPLA2R antibody levels (RR 0.67, 95% CI: 0.48, 0.94, P = 0.02). The occurrences of CRs, relapse rates, immunologic response rates, and SAE were not significantly different between RTX and CYC, respectively. In conclusion, although the long-term efficacy and safety of CYC compared to RTX were comparable, CYC might respond faster and be more advantageous in IMN patients with high antiPLA2R antibody titers.
| S-EPMC10517553 | biostudies-literature
Project description:Phospholipase A2 receptor 1 (PLA2R) is a target autoantigen in 70% of patients with idiopathic membranous nephropathy. We describe the location of a major epitope in the N-terminal cysteine-rich ricin domain of PLA2R that is recognized by 90% of human anti-PLA2R autoantibodies. The epitope was sensitive to reduction and SDS denaturation in the isolated ricin domain and the larger fragment containing the ricin, fibronectin type II, first and second C-type lectin domains (CTLD). However, in nondenaturing conditions the epitope was protected against reduction in larger fragments, including the full-length extracellular region of PLA2R. To determine the composition of the epitope, we isolated immunoreactive tryptic fragments by Western blotting and analyzed them by mass spectrometry. The identified peptides were tested as inhibitors of autoantibody binding to PLA2R by surface plasmon resonance. Two peptides from the ricin domain showed strong inhibition, with a longer sequence covering both peptides (31-mer) producing 85% inhibition of autoantibody binding to PLA2R. Anti-PLA2R antibody directly bound this 31-mer peptide under nondenaturing conditions and binding was sensitive to reduction. Analysis of PLA2R and the PLA2R-anti-PLA2R complex using electron microscopy and homology-based representations allowed us to generate a structural model of this major epitope and its antibody binding site, which is independent of pH-induced conformational change in PLA2R. Identification of this major PLA2R epitope will enable further therapeutic advances for patients with idiopathic membranous nephropathy, including antibody inhibition therapy and immunoadsorption of circulating autoantibodies.
| S-EPMC4310666 | biostudies-literature
Project description:Rituximab induces nephrotic syndrome (NS) remission in two-thirds of patients with primary membranous nephropathy (MN), even after other treatments have failed. To assess the relationships among treatment effect, circulating nephritogenic anti-phospholipase A2 receptor (anti-PLA2R) autoantibodies and genetic polymorphisms predisposing to antibody production we serially monitored 24-hour proteinuria and antibody titer in patients with primary MN and long-lasting NS consenting to rituximab (375 mg/m(2)) therapy and genetic analyses. Over a median (range) follow-up of 30.8 (6.0-145.4) months, 84 of 132 rituximab-treated patients achieved complete or partial NS remission (primary end point), and 25 relapsed after remission. Outcomes of patients with or without detectable anti-PLA2R antibodies at baseline were similar. Among the 81 patients with antibodies, lower anti-PLA2R antibody titer at baseline (P=0.001) and full antibody depletion 6 months post-rituximab (hazard ratio [HR], 7.90; 95% confidence interval [95% CI], 2.54 to 24.60; P<0.001) strongly predicted remission. All 25 complete remissions were preceded by complete anti-PLA2R antibody depletion. On average, 50% anti-PLA2R titer reduction preceded equivalent proteinuria reduction by 10 months. Re-emergence of circulating antibodies predicted disease relapse (HR, 6.54; 95% CI, 1.57 to 27.40; P=0.01), whereas initial complete remission protected from the event (HR, 6.63; 95% CI, 2.37 to 18.53; P<0.001). Eighteen patients achieved persistent antibody depletion and complete remission and never relapsed. Outcome was independent of PLA2R1 and HLA-DQA1 polymorphisms and of previous immunosuppressive treatment. Therefore, assessing circulating anti-PLA2R autoantibodies and proteinuria may help in monitoring disease activity and guiding personalized rituximab therapy in nephrotic patients with primary MN.
| S-EPMC4587688 | biostudies-literature
Project description:Primary membranous nephropathy (PMN) is a renal-specific autoimmune disease caused by circulating autoantibodies that target glomerular podocyte antigens (PLA2R/THSD7A). However, very little is known on the molecular mechanisms controlling B cell response in this nephropathy. The present study was aimed at correlating the serum levels of B cell activators BAFF/BLyS and APRIL with the presence of anti-PLA2R antibodies in PMN patients and with long-term clinical outcome. To this aim, 51 patients with anti-PLA2R-positive biopsy-proven PMN and nephrotic range proteinuria (>3.5 g/24 hours) were enrolled between January 2009 and December 2015 and treated with conventional 6-month immunosuppressive therapy. After 6 months, 29 patients (56.9%) cleared circulating anti-PLA2R, while in remaining 22 (43.1%), they persisted. Intriguingly, in the first group, baseline serum levels of BAFF/BLyS and APRIL were significantly lower than those in the second one. Moreover, after 6 months of immunosuppressive therapy, an overall reduction in both cytokine serum levels was observed. However, in PMN patients with anti-PLA2R clearance, this reduction was more prominent, as compared with those with anti-PLA2R persistence. When related to clinical outcome, lower baseline BAFF/BLyS (<6.05 ng/mL) and APRIL (<4.20 ng/mL) serum levels were associated with significantly higher probability to achieve complete or partial remission after 24-month follow-up. After dividing the entire study cohort into three groups depending on both cytokine baseline serum levels, patients with both BAFF/BLyS and APRIL below the cut-off showed a significantly higher rate of complete or partial remission as compared with patients with only one cytokine above the cut-off, while the composite endpoint was achieved in a very low rate of patients with both cytokines above the cut-off. Taken together, these results provide new insights into the role of BAFF/BLyS and APRIL in both the pathogenesis of anti-PLA2R-positive PMN and the response to immunosuppressive therapy.
| S-EPMC6874868 | biostudies-literature
Project description:Since urine samples more directly reflect kidney alterations and damage than blood samples, we investigated whether urine anti-PLA2R antibody (uPLA2R-Ab) could be utilized similarly to serum anti-PLA2R antibody (sPLA2R-Ab) as a noninvasive biomarker of idiopathic membranous nephropathy (IMN). In this study, we performed a qualitative analysis using an indirect immunofluorescence test (IIFT) and measured uPLA2R-Ab and sPLA2R-Ab concentrations using an enzyme-linked immunosorbent assay (ELISA) in 28 patients with biopsy-proven IMN and 12 patients with secondary membranous nephropathy (SMN). Overall, 64.3% (n=18) of patients with IMN had IIFT-positive sPLA2R-Ab, 67.9% (n=19) of patients with IMN had IIFT-positive uPLA2R-Ab, and none of the SMN patients had IIFT-positive sPLA2R-Ab or uPLA2R-Ab. The titers of the anti-PLA2R antibody from the IMN patients in the urine (10.72±22.24 RU/μmol, presented as uPLA2R-Ab/urine creatinine) and serum (107.36±140.93 RU/ml) were higher than those from the SMN patients (0.51±0.46 RU/μmol, 0.008±0.029 RU/ml, respectively, p<0.05). Statistical analyses indicated that there were positive correlations between uPLA2R-Ab and gPLA2R, sPLA2R-Ab or urinary protein and negative correlations between uPLA2R-Ab and serum albumin in patients with IMN. In conclusion, uPLA2R-Ab is a novel biomarker of IMN. sPLA2R-Ab combined with uPLA2R-Ab might be more helpful for diagnosis and activity in PLA2R associated MN.
| S-EPMC5787499 | biostudies-literature
Project description:Membranous Nephropathy (MN) is an autoimmune disease associated with antibodies against podocyte proteins: M-type phospholipase A2 receptor (PLA2R1) or thrombospondin type-1 domain-containing 7A (THSD7A) in 70 and 3% of patients, respectively. Antibody titer is correlated with disease activity: rising during active disease and decreasing before remission. Therefore, decreasing PLA2R1-Antibodies titer has become an important goal of therapy. Rituximab a chimeric monoclonal antibody induces remission in 60-80% of primary MN patients. All monoclonal antibodies such as rituximab can elicit antidrug antibodies, which may interfere with therapeutic response. We aim to analyze the relevance of anti-rituximab antibodies on the outcome of MN after a first course of rituximab. Forty-four MN patients were included and treated with two 1 g infusions of rituximab at 2-weeks interval. Anti-rituximab antibodies, CD19 count, and clinical response were analyzed. Then, we (i) analyzed the association of anti-rituximab antibodies at month-6 with response to treatment: remission, relapse and the need for another rituximab course; (ii) confirmed if anti-rituximab antibodies could neutralize rituximab B-cells depletion; and (iii) tested whether anti-rituximab antibodies could cross-inhibit new humanized anti-CD20 therapies. Anti-rituximab antibodies were detected in 10 patients (23%). Seventeen patients received a second rituximab course after a median time of 12 months (7-12), following nine cases of resistance and eight relapses. Anti-rituximab antibodies were significantly associated with faster B-cell reconstitution at month-6 (75 [57-89] vs. 2 [0-41] cells/μl, p = 0.006), higher proteinuria 12 months after rituximab infusion (1.7 [0.7; 5.8] vs. 0.6 [0.2; 3.4], p = 0.03) and before treatment modification (3.5 [1.6; 7.1] vs. 1.7 [0.2; 1.7] p = 0.0004). Remission rate 6 months after rituximab was not different according to anti-rituximab status (p > 0.99) but the rate of relapse was significantly higher for patients with anti-rituximab antibodies (p < 0.001). These patients required more frequently a second course of rituximab infusions (7/10 vs. 10/34, p = 0.03). Anti-rituximab antibodies neutralized rituximab activity in 8/10 patients and cross-reacted with other humanized monoclonal antibodies in only two patients. Three patients with anti-rituximab antibodies were successfully treated with ofatumumab. Anti-rituximab antibodies could neutralize rituximab B cells cytotoxicity and impact clinical outcome of MN patients. Humanized anti-CD20 seems to be a satisfying therapeutic alternative for patients with anti-rituximab antibodies and resistant or relapsing MN.
| S-EPMC6970431 | biostudies-literature
Project description:M-type phospholipase A2 receptor (PLA2R) is the major target antigen in primary membranous nephropathy (PMN). Previous studies have evaluated the diagnostic value of serum anti-PLA2R antibody. However, the correlation of serum anti-PLA2R antibody and glomerular PLA2R deposition, and their association with clinical characteristics need to be further evaluated.A total of 136 patients were involved as inception group because serum anti-PLA2R antibody and glomerular PLA2R antigen were simultaneously measured. We examined serum anti-PLA2R antibody by ELISA and glomerular PLA2R deposition by immunofluorescence assay.Positive serum anti-PLA2R antibody and glomerular PLA2R deposition were seen in 58.8% (80/136) and 95.6% (130/136) patients, respectively (P?<?.001). Proteinuria, serum total protein, serum albumin, serum creatinine, and estimated glomerular filtration rate (eGFR) had significant differences between patients with serum anti-PLA2R antibody and those without. Serum anti-PLA2R antibody levels were correlated with serum albumin, serum creatinine, eGFR, and proteinuria. Glomerular PLA2R deposition intensities were weakly correlated with proteinuria. Unexpectedly, there was a positive correlation rather than a negative correlation between glomerular PLA2R deposition intensity and eGFR.In conclusion, serum anti-PLA2R antibody is more closely correlated with disease activity and renal function than glomerular PLA2R deposition.
| S-EPMC5478356 | biostudies-literature
Project description:BackgroundThe 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.Method328 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.ResultLower 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).ConclusionGAg+/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.
| S-EPMC10566392 | biostudies-literature