anti-PLA2R Levels Research Articles

Prognostic and therapeutic monitoring value of plasma and urinary cytokine profile in primary membranous nephropathy: the STARMEN trial cohort

Abstract Background and hypothesis Primary membranous nephropathy (PMN) is usually caused by anti-PLA2R autoantibodies. There are different therapeutic options according to baseline risk. Novel biomarkers are needed to optimize risk stratification, and predict and monitor the response to therapy, as proteinuria responses may be delayed. We hypothesized that plasma or urinary cytokines may provide insight into the course and response to therapy in PMN. Methods Overall, 192 data-points from 34 participants in the STARMEN trial, randomized to tacrolimus-rituximab (TAC-RTX) or corticosteroids-cyclophosphamide (GC-CYC), were analyzed for plasma and urine cytokines using a highly sensitive chemiluminescence immunoassay providing a high-throughput multiplex analysis. Results Baseline (pretreatment) urinary CXCL13 predicted the therapeutic response to TAC-RTX. Cytokine levels evolved over the course of therapy. The levels of nine plasma and six urinary cytokines correlated with analytical parameters of kidney damage and disease activity, such as proteinuria, eGFR and circulating anti-PLA2R levels. The correlation with these parameters was most consistent for plasma and urinary GDF15, plasma TNF-α and urinary TWEAK. Decreasing plasma GDF15 levels were associated to response to GC-CYC. Four clusters of cytokines were associated to different stages of response to therapy in the full cohort, with the less inflammatory cluster associated to remission. Conclusion In conclusion, PMN displayed characteristic plasma and urine cytokine patterns that evolved over time as patients responded to therapy. Baseline urinary CXCL13 concentration could be a prognostic marker of response to TAC-RTX.

#1649 Obinutuzumab is effective for the treatment of rituximab-resistant membranous nephropathy

Abstract Background and Aims Membranous nephropathy (MN) is a leading cause of nephrotic syndrome in nondiabetic adults. Rituximab has become the first-line therapy for patients with MN after the recognition of MN as an autoimmune disease. However, 40% of patients with MN do not respond to rituximab. Obinutuzumab is a humanized and glycoengineered type II anti-CD20 monoclonal antibody that has superior in vitro B-cell cytotoxicity compared with rituximab which might provide an attractive option for rituximab-resistant MN. We presented our single-center experience of treating MN with obinutuzumab. Method Fourteen patients with rituximab-resistant PLA2R-associated MN who received obinutuzumab at the First affiliated hospital of Xi'an Jiaotong university between January 2022 and June 2023 were included in this retrospective study. Resistance to rituximab was defined as the failure to achieve complete (urinary protein excretion <0.3 g/d along with normal serum albumin concentration and stable renal function) or partial (urinary protein excretion <3.5 g/d or with ≥50% reduction vs baseline, accompanied by improvement or normalization of serum albumin concentration and stable GFR) remission of NS in 3-6 months after 2 doses of rituximab administration. Clinical and laboratory parameters were evaluated at presentation, before and after obinutuzumab administration. Results Of all patients with an average age of 50.0 ± 13.6 years, 10 (71.4%) patients were men, 8 (57.1%) patients had hypertension and 4 (28.6%) patients had diabetes. The median disease duration was 1.3 (1.0, 4.8) years. At presentation, the proteinuria and albumin levels were 7.94 ± 4.23 g/d and 21.5 ± 3.6 g/L, respectively. The mean serum creatinine level was 70.5 ± 10.7 µmol/L and the patients had a median baseline anti-PLA2R level of 193.5 (104.5,299.2) RU/mL. Six patients had been previously exposed to steroids, alkylating agents, calcineurin inhibitors in different combinations in addition to rituximab. Both patients received 1 g of obinutuzumab on day 0 and day 15. At obinutuzumab administration, the proteinuria and albumin levels were 8.43 ± 3.36 g/d and 22.4 ± 4.0 g/L, respectively. The mean serum creatinine level was 85.1 ± 28.5 µmol/L and median anti-PLA2R level decreased to 32.7 (10.7,178.) RU/mL compared with that at presentation. After a median follow-up of 5.4 (4.0, 9.7) months after obinutuzumab therapy, complete remission was achieved in 4 (28.6%) and partial remission was achieved in 8 (57.1%) of patients. Of the remaining two patients who did not achieve complete or partial remission, 1 patient had a follow-up of 4 months and had a 33% decline in proteinuria accompanied by improvement in serum albumin. The other patient had an anti-PLA2R level higher than 1500 RU/mL (exceeding detection upper limit) at obinutuzumab administration and an inadequate follow-up of 3 months without proteinuria decline. Whereas, anti-PLA2R level decreased to 18.17 RU/ml accompanied by B-lymphocyte depletion (absolute CD19 count <5 cells/ml) at that time. Of the 12 patients who achieved complete or partial remission, the median time from treatment to remission was 4.7 ± 2.3 months. Two patients with longer follow-up maintained complete remission at 1 year. At first complete or partial remission, the proteinuria and albumin levels were 3.47 ± 1.99 g/d and 32.5 ± 3.3 g/L, respectively. The mean serum creatinine level was 74.8 ± 24.1 µmol/L and anti-PLA2R levels of 11 patients had a decline in the titer to <2 RU/ml (negative result for our immunology laboratory). B-lymphocyte depletion was achieved in all these patients. Conclusion Obinutuzumab may represent an attractive alternative therapy in patients with resistance to rituximab. Larger prospective studies are needed to validate these findings.

#2388 Relevance of anti-PLA2R levels in therapy decision and prediction of therapy outcome in patients with membranous nephropathy

Abstract Background and Aims Detection of anti-phospholipase A2 receptor (PLA2R) antibodies in patients with primary membranous nephropathy (MN) supports diagnosis as well as disease monitoring. An individualised therapy approach was introduced for anti-PLA2R positive MN patients at the Radboud University Medical Center. Immunosuppressive treatment (cyclophosphamide combined with steroids) was stopped when anti-PLA2R results by indirect immunofluorescence testing (IIFT) became negative. Here, we evaluated the relevance of anti-PLA2R levels for therapeutic decisions and the outcome of MN, comparing qualitative and quantitative detection methods. Method Stored serum samples were retrieved for beginning of treatment (baseline), decision point, and follow-up. Anti-PLA2R levels were determined qualitatively by IIFT as well as quantitatively by enzyme-linked immunosorbent assay (ELISA) and chemiluminescence immunoassay (ChLIA) at baseline as well as after treatment and correlated to immunological remission and persistence. Results For an evaluation of the relevance of anti-PLA2R levels at the start of therapy, serum samples of 60 patients were available. Patients sampled at the beginning of the therapy were grouped according to tertiles of anti-PLA2R levels determined by ChLIA (n[lowest tertile] = 20, n[middle tertile] = 20, n[highest tertile] = 20). Lower anti-PLA2R levels were seen in patients with relapsing disease. Higher anti-PLA2R levels were associated with more severe proteinuria. Patients in the lowest tertile of anti-PLA2R were more likely to develop immunological remission after 8 weeks of therapy. In total, 90% vs 75% vs 45% of patients in the tertiles turned anti-PLA2R negative after being treated for 8 weeks. Moreover, in this subgroup of patients who showed immunological remission after 8 weeks of therapy, only 11% of the patients in the lowest tertile needed renewed immunosuppressive therapy, while this percentage increased in the middle and highest tertiles (11% vs 53% vs 33%, p=0.033). For the assessment of anti-PLA2R levels before and after therapy, samples at baseline and week 8 of treatment were examined. At baseline, 50/50 (100%) tested positive in IIFT and ChLIA as well as 48/50 (94%) in ELISA. After 8 weeks on treatment, immunological remission based on IIFT was found in 37/51 (73%) patients. At this point, the overall agreement compared to IIFT was 92% for ChLIA and 82% for ELISA. Yet the availability of quantitative levels provided further insight into this group of patients in whom treatment was discontinued. With ChLIA, anti-PLA2R titers >5 RU/mL after 8 weeks of therapy were found in 4% of IIFT negative patients with persistent remission, vs 55% of IIFT negative patients with early relapse (p=0.006). Conclusion Individualised treatment of MN patients with cyclophosphamide and steroids has been recently introduced. In this respect, the quantitative determination of anti-PLA2R levels adds further value. Of the examined quantitative methods, ChLIA demonstrated the highest agreement with IIFT. Additional studies are needed to evaluate the impact on clinical decision making and outcome.

#2890 Role of alternative pathway of complement system in membranous nephropathy: a study from STARMEN clinical trials

Abstract Background and Aims Membranous nephropathy (MN) is an antibody-mediated autoimmune disease characterized by glomerular immune complexes containing complement components. A recent animal model of PLA2r antibody-induced MN induced has demonstrated the crucial role of complement pathway, although is still unclear which complement pathway is most involved in its pathogenesis This study aimed to explore the role of alternative pathway of complement cascade in a cohort of patients from STARMEN clinical trial. Method We analyzed longitudinal plasma samples from 51 patients from STARMENT cohort stored in a biobank. Samples were stored at enrollment and longitudinally throughout the follow up at 3, 6, 9, 12, 18 and 24 months. We measured the circulating plasma levels of C3, FB, FH, FHR1, FHR2 and FHR5 in every time. Results Fifty-two patients with a mean age of 56 ± 10 years and 60% male were included. 44% were treated with tacrolimus+Rituximab and 56% with ponticelli regimen. The basal creatinine was 0.9 ± 0.3 mg/dl, median proteinuria/day was 8.8 g/day (IQR 5.7-11.6 gr/day) and serum albumin of 2.6 g/dl (IQR 2.3-2.9 g/dl). All patients were followed-up for two years. Thirty-four patients achieved complete remission (CR), 11 patients partial remission (PR) and 15 did not respond (including relapse). During active disease, the mean concentration of FH, FHR-1 and FHR-2 were significantly increased compared with remission status (complete or partial). We did not find different in other factors: FB or FHR-5. Moreover, a positive correlation was observed between FH and FB with C3. There were no differences according to treatment arm. PLA2r antibodies tested positive in 68%. The median of baseline anti-PLA2R title levels was 80 RU/ml (IQR 43-141). Circulating plasma levels of FHR1 at baseline were significantly higher in PLA2r testing negative vs positive patients (199 ± 108 vs 249 ± 41 µg/ml, p = 0.021). This significant difference was present when remission was achieved (205 ± 97 vs 264 ± 49 µg/ml, p = 0.023). Similar tendency was observed for FB. Conclusion These data provide evidence of complement system activation through the alternative pathway in membranous nephropathy. We know that different subtypes of IgG are behind the different antibodies-induced MN induced, and that every subtype active different complement pathway. The results of this study lead to speculate that not all the antigens that induced MN active complement pathway in the same way.

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.

Rituximab may affect T lymphocyte subsets balance in primary membranous nephropathy

BackgroundThe aim of this study was to investigate the effects and significance of rituximab (RTX) on the levels of T lymphocyte subsets in patients diagnosed with primary membranous nephropathy (PMN).MethodsA total of 58 PMN patients and 25 healthy donors were chosen as the subjects. Among the PMN patients, 40 individuals received RTX treatment and completed at least 6 months of follow-up. All subjects underwent flow cytometry analysis to determine the peripheral blood lymphocyte subsets. The changes in anti-PLA2R antibody titers and 24-hour urinary protein levels were evaluated by ELISA and Biuret method before and after treatment.Results(1) The PMN group exhibited a significantly greater percentage of peripheral blood CD3−CD19+ B cells than the healthy group, which is consistent with the findings of previous reports. Additionally, compared with those in the peripheral blood of healthy individuals, the numbers of CD4+ central memory T cells, CD4+ effector memory T cells, CD4+/CD8+, and CD4+CD25+ T cells in the PMN peripheral blood were markedly greater. However, the number of peripheral blood Treg cells was reduced in the PMN group. (2) After 6 months of RTX treatment, PMN patients exhibited significant decreases in anti-PLA2R antibody titers, 24-hour urinary protein levels, and peripheral blood CD3−CD19+ B cells. Importantly, RTX administration decreased CD4+CD25+ T cells and CD4+/CD8+ in the peripheral blood of PMN patients and improved Treg cell levels. (3) RTX treatment induced alterations in the CD4+ T lymphocyte subsets in PMN patients, which did not correlate with B lymphocyte counts or anti-PLA2R antibody titers.ConclusionsRTX treatment might have a beneficial impact on cellular immunity by effectively restoring the balance of CD4+ T lymphocyte subsets in PMN patients, which is beyond its effects on B cells and antibody production.Trial registrationThe research was registered at the First Affiliated Hospital of Soochow University. Registration Number: MR-32-23-016211. Registration Date: May 31, 2023.

Bi-specific autoantigen-T cell engagers as targeted immunotherapy for autoreactive B cell depletion in autoimmune diseases.

In autoimmune diseases, autoreactive B cells comprise only the 0.1-0.5% of total circulating B cells. However, current first-line treatments rely on non-specific and general suppression of the immune system, exposing patients to severe side effects. For this reason, identification of targeted therapies for autoimmune diseases is an unmet clinical need. Here, we designed a novel class of immunotherapeutic molecules, Bi-specific AutoAntigen-T cell Engagers (BiAATEs), as a potential approach for targeting the small subset of autoreactive B cells. To test this approach, we focused on a prototype autoimmune disease of the kidney, membranous nephropathy (MN), in which phospholipase A2 receptor (PLA2R) serves as primary nephritogenic antigen. Specifically, we developed a BiAATE consisting of the immunodominant Cysteine-Rich (CysR) domain of PLA2R and the single-chain variable fragment (scFv) of an antibody against the T cell antigen CD3, connected by a small flexible linker. BiAATE creates an immunological synapse between autoreactive B cells bearing an CysR-specific surface Ig+ and T cells. Ex vivo, the BiAATE successfully induced T cell-dependent depletion of PLA2R-specific B cells isolated form MN patients, sparing normal B cells. Systemic administration of BiAATE to mice transgenic for human CD3 reduced anti-PLA2R antibody levels following active immunization with PLA2R. Should this approach be confirmed for other autoimmune diseases, BiAATEs could represent a promising off-the-shelf therapy for precision medicine in virtually all antibody-mediated autoimmune diseases for which the pathogenic autoantigen is known, leading to a paradigm shift in the treatment of these diseases.

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 > 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 < 0.05). Additionally, after 3 months of treatment, there was a notable difference in the serum albumin levels between the two groups (P < 0.05). However, after 6 and 12 months of treatment, there was no significant difference in serum albumin levels between the two groups (P > 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 > 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.

Cyclophosphamide induced early remission and was superior to rituximab in idiopathic membranous nephropathy patients with high anti-PLA2R antibody levels

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.

Anti-PLA2R Antibody Levels and Clinical Risk Factors for Treatment Nonresponse in Membranous Nephropathy.

The 2021 Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend following anti-phospholipase A2 receptor (PLA2R) antibody levels as a marker of treatment response in membranous nephropathy; however, the optimal timing to evaluate antibody levels and how to combine them with other clinical variables are currently unknown. We used a cohort of 85 patients from the Membranous Nephropathy Trial Of Rituximab (MENTOR) with anti-PLA2R antibodies ≥14 RU/ml to identify risk factors for not experiencing proteinuria remission after 12 months of treatment with cyclosporine or rituximab. Three landmark times were considered: at baseline and after 3 and 6 months of treatment. Logistic regression model performance was evaluated using C-statistics and model fit (Akaike information criterion [AIC], R 2 ). The model at baseline that best predicted no remission included anti-PLA2R antibodies >323 RU/ml and creatinine clearance; the best model after 3 months included the change from baseline in both antibody and albumin levels; and the best model after 6 months included antibody levels >14 RU/ml, creatinine clearance, and the change from baseline in albumin. Compared with the model at baseline, the model at 3 months had better model fit (AIC 70.9 versus 96.4, R 2 51.8% versus 30.1%) and higher C-statistic (0.93 versus 0.83, P = 0.008). The model at 6 months had no difference in performance compared with the model at 3 months (AIC 68.6, R 2 53.0%, C-statistic 0.94, P = 0.67). In patients with membranous nephropathy treated with cyclosporine or rituximab in the MENTOR trial, we found that the optimal method to evaluate risk factors for the probability of treatment response was to use anti-PLA2R antibody levels combined with albumin levels after 3 months of treatment, which was significantly better than using antibody levels alone or risk factor evaluation at baseline, with no added benefit of waiting until 6 months of treatment. This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_10_09_CJN0000000000000237.mp3.

#5215 OFATUMUMAB AS A RESCUE THERAPY FOR PATIENTS WITH MEMBRANOUS NEPHROPATHY

Abstract Background and Aims Rituximab is the first-line treatment for patients with primary membranous nephropathy (MN) and nephrotic syndrome (NS) at high risk of progression to end-stage kidney disease. However, this drug is effective only in approximately two thirds of treated patients, and repeated rituximab infusions may be complicated by hypersensitivity reactions, which contraindicate retreatment. Ofatumumab, a fully human anti-CD20 antibody, could overcome these limitations. Method We retrospectively evaluated the response to a single 50–300 mg dose of intravenous ofatumumab in 17 MN patients referred to our institution who either experienced hypersensitivity reactions (rituximab-intolerant, n = 5) or failed to achieve NS remission after rituximab infusion (rituximab-resistant, n = 12). Results Over a median [IQR] follow-up of 5.0 [3.0-9.8] months, ten (58.8%) patients—five rituximab-resistant (41.7%) and all five rituximab-intolerant—achieved complete or partial NS remission, defined as proteinuria <0.3 g/day or proteinuria <3.5 g/day with ≥50% reduction from baseline, respectively. Ofatumumab infusion induced a progressive reduction in 24-hour urinary protein and IgG excretion, and a sharp increase in serum albumin and IgG levels. Peripheral B cells were depleted in all patients and started reconstituting by 3 months from baseline. Seven of the 12 subjects with PLA2R-related disease (i.e. with baseline anti-PLA2R antibody levels >2.7 RU/mL by ELISA) achieved antibody depletion during the follow-up (half of rituximab-resistant and all rituximab-intolerant). There were 14 non-serious infusion-related adverse events in nine patients, all of which completely resolved with temporary interruption of ofatumumab infusion. Conclusion Ofatumumab may be an effective and safe treatment option for all rituximab-intolerant and a substantial proportion of rituximab-resistant MN patients.

Relationship Between the Efficacy of Low-Dose Glucocorticoids Combined with Tacrolimus in the Treatment of Adult Idiopathic Membranous Nephropathy and the Level of Serum Anti-PLA2R Antibodies

Objective: To further evaluate the efficacy and safety of low-dose glucocorticoids combined with tacrolimus in the treatment of adult idiopathic membranous nephropathy (IMN) in a clinical setting. Methods: We carried out a single-center prospective study of 88 patients with IMN who were admitted into the Affiliated Hospital of Hebei University from January 2019 to December 2021, and the participants were divided into two groups based on their serum anti-PLA2R antibody levels: the negative group and the positive group. 46 patients were positive for anti-PLA2R antibodies and 42 were negative. Results: After 6 months of treatment, the serum albumin, cholesterol, and 24h urine protein quantification in the anti-PLA2R negative group improved more significantly compared to the positive group (P < 0.05); after 6 months of treatment, the remission rate of the positive group was significantly lower than that of the negative group, and (P < 0.05); Conclusion: After treatment with tacrolimus combined with low-dose glucocorticoids, patients with idiopathic membranous nephropathy who were tested positive for anti-PLA2R antibodies had a higher overall remission rate compared those who were tested negative for serum anti-PLA2R antibodies.

Anti-phospholipase A2 Receptor Antibody Measurement in Patients with Idiopathic Membranous Nephropathy Diagnosed by Renal Biopsy

Objective: Our study is a cross-sectional study that aims to evaluate the presence and levels of anti-phospholipase A2 receptor (PLA2R) antibodies in healthy volunteers and idiopathic membranous nephropathy (IMN) patients and to assess the relationship between these levels and clinical parameters. Methods: Serum anti-PLA2R antibody levels, complete blood count, urea, creatinine (Kre), total protein,albumin, low-density lipoprotein (LDL)-cholesterol, triglycerides (TG), high-density lipoprotein (HDL)-cholesterol, total cholesterol, C-reactive protein (crp), sedimentation, proteinuria were measured from 71 IMN patients and 48 healthy volunteers. Results: Of the values compared between the two groups, the urea, creatinine, and modified diet renal disease (MDRD) were similar, total protein, albumin, LDL-cholesterol, TG, total cholesterol, HDL-cholesterol, and complete urinalysis protein values were statistically significantly high in the patient group, as expected in nephrotic syndrome (p<0.01). The anti-PLA2Rantibody levels measured using enzyme-linked immunosorbent assay (ELISA) in patient and control groups were found to be negative. The anti-PLA2R level was found to be 0.104 (0.093-0.129) ng/ml in the IMN group, while it was 0.141 (0.117-0.177) ng/ml in the control group (P=0,001). Although the P value was significant, the anti-PLA2R antibody level was found to be high in the control group and was outside the reference range of the kit. Conclusion: There is a need to conduct more sensitive studies with a higher number of patients in order to distinguish between primary and secondary nature and to investigate the presence of anti-PLA2R in IMNpatients, which constitute the majority of nephrotic syndromes in adults. Antibody titer levels were observed to be low and it was revealed that the measurement range of the antibody kit used in the study should be more sensitive.

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.

The place of cyclical therapy for the treatment of membranous nephropathy in the era of rituximab.

Primary membranous nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults, due to a variety of autoantibodies, most frequently against phospholipase A2 receptor (PLA2R). In severe cases or when spontaneous remission is not achieved, immunosuppression is required. Cyclical therapy, based on glucocorticoids and cyclophosphamide on alternate months for 6months, has proven effective to induce remission and reduce the risk of end-stage renal disease. Since the early 2000s, rituximab (RTX) has emerged as a key player in the management of MN, showing overall comparable effectiveness and likely better safety compared with the cyclical regimen, despite the lack of adequately powered trials comparing the two approaches head to head. For these reasons, RTX is now considered the agent of choice for most patients with MN. However, there are still uncertainties. Around 20-40% of patients are resistant to RTX, especially in the setting of high anti-PLA2R levels, and this drug remains relatively unexplored in patients with the most severe disease. In these scenarios, although the expanding therapeutic armamentarium is probably going to provide further options, the cyclical regimen still plays a key role as a safety net. The aim of this article is to illustrate the role of cyclical therapy in the RTX era.

Treatment with rituximab and hydroxychloroquine in a patient with membranous nephropathy and diabetic nephropathy: A case report

Abstract Nephrotic syndrome (NS), which includes primary and secondary types, is one of the causes of end-stage kidney disease. Common causes in adults include diabetic nephropathy (DN), membranous nephropathy (MN), and focal segmental glomerulosclerosis. About 30%–40% of diabetics can develop into DN. The incidence of primary nephrotic syndrome in diabetic patients was not significantly different from that in the general population. Herein we present a windfall from the treatment of rituximab combined with hydroxychloroquine in a patient with primary MN and DN. A 51-year-old Chinese man, diagnosed with type 2 diabetes mellitus (T2DM) 12 years ago, was admitted to the hospital due to edema of bilateral lower limbs and severe proteinuria. Serology showed the obvious elevation of the anti-phospholipase A2 receptor (anti-PLA2R) level and renal biopsy showed MN concomitant with DN. After low dosage of prednisone and standard dosage of rituximab, the patient’s proteinuria decreased; however, the effect was unsatisfactory and proteinuria was elevated again in 8 months. Thus, treatment with rituximab and hydroxychloroquine was initiated, which resulted in proteinuria diminishing significantly and albumin returning to normal level. Therefore, even complicated with DN, patients diagnosed with primary MN still have a promising remission after being treated with rituximab and hydroxychloroquine.

Successful treatment of patients with refractory idiopathic membranous nephropathy with low-dose Rituximab: A single-center experience.

The recognition of idiopathic membranous nephropathy (IMN) as an autoimmune disease has paved the way for the use of B-cell-depleting agents, such as Rituximab (RTX), which is now a first-line drug for treating IMN with proven safety and efficacy. Nevertheless, the usage of RTX for the treatment of refractory IMN remains controversial and challenging. To evaluate the efficacy and safety of a new low-dose RTX regimen for the treatment of patients with refractory IMN. A retrospective study was performed on refractory IMN patients that accepted a low-dose RTX regimen (RTX, 200 mg, once a month for five months) in the Xiyuan Hospital of Chinese Academy of Chinese Medical Sciences' Department of Nephrology from October 2019 to December 2021. To assess the clinical and immune remission data, we performed a 24 h urinary protein quantification (UTP) test and measured the serum albumin (ALB) and serum creatinine (SCr) levels, phospholipase A2 receptor (PLA2R) antibody titer, and CD19+ B-cell count every three months. A total of nine refractory IMN patients were analyzed. During follow-up conducted twelve months later, the results from the 24 h UTP decreased from baseline [8.14 ± 6.05 g/d to 1.24 ± 1.34 g/d (P < 0.05)] and the ALB levels increased from baseline [28.06 ± 8.42 g/L to 40.93 ± 5.85 g/L (P < 0.01)]. Notably, after administering RTX for six months, the SCr decreased from 78.13 ± 16.49 μmol/L to 109.67 ± 40.87 μmol/L (P < 0.05). All of the nine patients were positive for serum anti-PLA2R at the beginning, and four patients had normal anti-PLA2R titer levels at six months. The level of CD19+ B-cells decreased to 0 at three months, and CD19+ B-cell count remained at 0 up until six months of follow-up. Our low-dose RTX regimen appears to be a promising treatment strategy for refractory IMN.

Determination of Anti-Phospholipase A2 and Anti-Thrombospondin Type 1 Domain-Containing Protein 7A in Latin Patients with Membranous Nephropathy

Primary membranous nephropathy (MN) is caused by antibodies against podocyte antigens, especially the type M receptor of phospholipase A2 (PLA2R) and thrombospondin type-1 domain containing 7 A (THSD7A). This study's aim was the determination of anti-PLA2R, anti-THSD7A serum antibodies, and anti-PLA2R renal tissue staining prevalence in a Latin population with MN, as well as evaluating their role as biomarkers for disease activity. The performance of the two anti-PLA2R serum diagnostic methods-ELISA and indirect immunofluorescence (IFI)-was evaluated for the diagnosis of MN. Fifty-nine patients, including 29 with MN, 18 with lupus membranous nephropathy (LMN) and 12 with focal and segmental glomerulosclerosis (FSGS), were evaluated for serum antibodies. Renal biopsies were also evaluated for the presence of anti-PLA2R staining. Twenty-one patients with MN were followed for 1 year. Patients with LMN and FSGS were negative for both antibodies. All 29 MN patients were negative for anti-THSD7A; 16 MN patients were positive for anti-PLA2R by ELISA and/or IFI, and 3 MN patients were positive for anti-PLA2R only by IFI. Thus, the anti-PLA2R ELISA test demonstrated 45% sensitivity and 97% specificity, while the IFI test showed, respectively, 55% and 100% in our MN patients. Among the 28 MN renal biopsies, 20 presented anti-PLA2R positive staining, corresponding to a 72% sensitivity. Positive correlations were observed between the anti-PLA2R ELISA titer and proteinuria. In conclusion, determination of anti-PLA2R antibodies in the MN Latin population showed similar rates to those reported for other populations. The anti-PLA2R serum levels correlated with MN disease activity.

Long-term efficacy of low-dose rituximab treatment in patients with primary membranous nephropathy

Objective: To explore the long-term efficacy of low-dose rituximab (RTX) treatment in patients with primary membranous nephropathy (PMN). Methods: Patients with biopsy-proven PMN who received low-dose RTX as initial or second-line regimen from August 2018 to May 2020 in the Department of Nephrology, Tianjin Medical University General Hospital were respectively enrolled. The clinical parameters of patients were urinary protein>3.5 g/24 h, serum albumin<30 g/L and estimated glomerular filtration rate (eGFR)>20 ml·min-1·(1.73 m2)-1. The treatment response of patients with PMN was observed during follow-up, and the remission rate of patients with urinary protein<8 g/24 h or ≥8 g/24 h, anti-PLA2R antibody<150 RU/ml or ≥150 RU/ml, eGFR≥ 60 ml·min-1·(1.73 m2)-1 or<60 ml·min-1·(1.73 m2)-1 were analyzed, respectively. Results: A total of 40 patients were enrolled, including 26 males and 14 females, aged (53±15) years. There were 14 patients received RTX as initial treatment and 26 patients as second-line therapy. The total median dose of RTX in the first course was 800 (425, 1 075) mg. The overall remission rate at the 1st, 3rd, 6th, 12th and 24th months were 12.5% (5/40), 17.5% (7/40), 47.5% (19/40), 57.5% (23/40), 60% (24/40), respectively. The median overall response time was 6.0 (3.0, 7.5) months. Two cases relapsed. Patients with remission (n=24) had a higher level of baseline eGFR [(93.9±28.0) vs (62.4±28.1) ml·min-1·(1.73 m2)-1, P=0.001), and a lower level of both urinary protein [5.9 (5.0, 6.5) vs 11.7 (8.6, 15.5) g/24 h, P<0.001] and anti-PLA2R antibody level [73 (29, 132) vs 453 (182, 950) RU/ml, P=0.004] than those without remission (n=16) 24 month after treatment. There was no statistically significant difference in the remission rate between initial and second-line treatment (P=0.101). Moreover, patients had a higher remission rate in urinary protein<8 g/24 h group (21/26 vs 3/14, P<0.001), anti-PLA2R antibody<150 RU/ml group (16/19 vs 5/16, P=0.002) and eGFR ≥ 60 ml·min-1·(1.73 m2)-1 group (22/29 vs 2/11, P=0.003). Conclusions: Low-dose RTX treatment in PMN is effective during long-term follow-up, and has a lower recurrence rate. The results also suggest that it is more suitable for patients with baseline urinary protein<8 g/24 h, anti-PLA2R antibody<150 RU/ml and eGFR≥ 60 ml·min-1·(1.73 m2)-1.

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

BackgroundIdiopathic 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.MethodsThis 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.ResultsThe 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.ConclusionAnti-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.