Anti-phospholipase A2 Receptor Antibody Research Articles

Treating primary membranous nephropathy with extremely high titer of anti-phospholipase A2 receptor antibodies: A case of failed treatment with very high-dose rituximab.

Rituximab (RTX) is the anti-CD20 monoclonal antibody that has been used as the first-line therapy for primary membranous nephropathy (PMN) in recent years. However, the optimal dosing regimen and timing of RTX, or combination with other immunosuppressants, especially in patients with extremely high titers (>1,000 RU/mL) of anti-PLA2R antibody (aPLA2R), are unclear at present. This report describes the case of a 70-year-old PMN patient with extremely high aPLA2R titer who failed to respond to very high doses of RTX. We also discuss the possible reasons for treatment failure.

Comparison of obinutuzumab and rituximab for treating primary membranous nephropathy.

This study compared the effectiveness and safety profiles of obinutuzumab and rituximab in the treatment of patients with primary membranous nephropathy. Patients with primary membranous nephropathy who had urine protein ≥ 3.5 g/24 hours and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2 despite six months of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker and treatment with obinutuzumab or rituximab were included and matched by propensity score (ratio: 1:2) based on age, sex, urine protein, eGFR, and titers of Anti-Phospholipase A2 receptor (PLA2R) antibody. The primary outcome was defined as a combination of partial or complete remission at 12 months. Logistic regression models, Kaplan Meier curves, and absolute risk differences were employed to compare the therapeutic effectiveness and safety profiles of obinutuzumab and rituximab. Sixty-three patients with primary membranous nephropathy were included in the study, with 21 patients receiving obinutuzumab and 42 patients receiving rituximab. At 12 months, the primary outcome was achieved in 20 of 21 patients in the obinutuzumab group and 28 of 42 patients in the rituximab group (obinutuzumab vs. rituximab: 95% vs. 67%; odds ratio (OR): 10.00, 95% confidence intervals (CI):1.21-82.35, P=0.03). Moreover, patients in the obinutuzumab group acquired more complete remission (obinutuzumab vs. rituximab: 38% vs. 14%; OR: 3.69, 95% CI:1.08-12.68, P=0.04). In PLA2R-associated primary membranous nephropathy subgroup analyses, patients in obinutuzumab group sustained lower CD19 B cell counts (CD19 B cell counts: median (IQR) 0 (0-6) cells/ul vs. 20 (3-58) cells/ul, P=0.002) and were more prone to achieve immunological remission (defined as PLA2R antibody <2 RU/ml) at six months [obinutuzumab vs. rituximab: 92% (12 out of 13) vs. 64% (16 out of 25), P=0.06] than rituximab. Both treatment regimens were well tolerated. Our study demonstrated that obinutuzumab is associated with higher odds of clinical remission compared to rituximab at 12 months which may be due to higher immunological remission at six months with a similar safety profile in patients with primary membranous nephropathy.

The correlation between anti-phospholipase A2 receptor antibodies and hypercoagulability in patients with idiopathic membranous nephropathy

Background Patients with idiopathic membranous nephropathy (IMN) are more likely to be complicated by venous thromboembolism (VTE). The aim of the study was to investigate the potential association between anti-phospholipase A2 receptor (PLA2R) antibodies and hypercoagulability in patients with IMN. Methods A total of 168 patients with biopsy-proven IMN and 36 patients with biopsy-proven minimal change disease (MCD) were enrolled in this study. The clinical data, serum anti-PLA2R antibodies and coagulation-related indices of the patients were retrospectively analyzed. Results Patients with IMN were categorized into glomerular PLA2R staining-positive (GAg+) IMN group and glomerular PLA2R staining-negative (GAg-) IMN group in the study. Patients with IMN who were GAg + had lower PT, APTT and R time than patients with IMN who were GAg-, while the CI value was higher in patients with IMN who were GAg+. Patients with IMN who were GAg + were divided into the SAb+/GAg + group and the SAb-/GAg + group. Patients with IMN who were SAb+/GAg + had higher Fib and MA values than patients with IMN who were SAb-/GAg+. Correlation analysis showed that serum anti-PLA2R antibodies were positively correlated with fibrinogen, D-dimer, K time, CI value, α-angle, and MA value. Multiple linear regression analysis indicated that anti-PLA2R antibodies were independently correlated with fibrinogen and MA value. Conclusion Our study provides a new perspective on the underlying mechanisms of hypercoagulability in patients with IMN. Anti-PLA2R antibodies are associated with hypercoagulability in patients with IMN and may affect coagulation in patients with IMN by affecting platelet aggregation function and fibrinogen counts.

Effect of cyclophosphamide combined with glucocorticoid therapy on idiopathic membranous nephropathy: A multicenter open-label randomized controlled trial.

We aimed to evaluate the effect of cyclophosphamide combined with glucocorticoid therapy on idiopathic membranous nephropathy through a multicenter open-label randomized controlled trial. 92 patients with idiopathic membranous nephropathy admitted from March 2020 to September 2022 were included and assigned to a control group (n=46) and a research group (n=46) using a random number table. The control group was given glucocorticoid, and the research group was given cyclophosphamide combined with glucocorticoid. Clinical efficacy, renal function-related indicators (serum creatinine, blood urea nitrogen and albumin, and 24-hour urine protein quantification), inflammatory factors (interleukin (IL)-6, IL-18, transforming growth factor-β, and tumor necrosis factor-α), immune function-related indicators (anti-phospholipase A2 receptor antibody, and T-lymphocyte subsets), oxidative stress-related indicators (heme oxygenase-1, superoxide dismutase, malondialdehyde, and nitric oxide), blood lipid-related indicators (total cholesterol, triacylglycerol, and low-density lipoprotein), and adverse reactions were compared. The overall remission rate of the research group was higher than that of the control group (93.48 vs. 78.26%, p<0.05). After treatment, the research group had lower levels of 24-hour urine protein quantification, serum creatinine, blood urea nitrogen, IL-6, IL-18, transforming growth factor-β, tumor necrosis factor-α, heme oxygenase-1, malondialdehyde, anti-phospholipase A2 receptor antibody, CD8+, total cholesterol, triacylglycerol and low-density lipoprotein, higher levels of albumin, superoxide dismutase, nitric oxide, and CD4+ and a higher CD4+/CD8+ ratio than the control group (p<0.05). Cyclophosphamide combined with glucocorticoid therapy is effective for improving the overall remission rate and can suppress inflammatory responses and oxidative stress in patients with idiopathic membranous nephropathy.

Macrocarpal B blocks the binding between the phospholipase A2 receptor and its antibodies

The pathogenic role of anti-phospholipase A2 receptor (PLA2R) antibodies in primary membranous nephropathy (MN) has been well-established. This study aimed to identify potential small-molecule inhibitors against the PLA2R-antibody interaction, offering potential therapeutic benefits. A comprehensive screening of over 4000 small-molecule compounds was conducted by ELISA to assess their inhibitory effects on the binding between the immobilized full-length extracellular PLA2R and its antibodies. The affinity of anti-PLA2R IgG from MN patients and the inhibitory efficacy of each compound were evaluated via surface plasmon resonance (SPR). Human podocyte injuries were analyzed using CCK-8 assay, wound healing assay, western blot analysis, and immunofluorescence, after exposure to MN plasma +/- blocking compound. Fifteen compounds were identified as potential inhibitors, demonstrating inhibition rates >20 % for the PLA2R-antibody interaction. Anti-PLA2R IgG exhibited a consistent affinity among patients (KD = 10−8 M). Macrocarpal B emerged as the most potent inhibitor, reducing the antigen–antibody interaction by nearly 30 % in a dose-dependent manner, comparable to the performance of the 31-mer peptide from the CysR domain. Macrocarpal B bound to the immobilized PLA2R with an affinity of 1.47 × 10−6 M, while showing no binding to anti-PLA2R IgG. Human podocytes exposed to MN plasma showed decreased podocin expression, impaired migration function, and reduced cell viability. Macrocarpal B inhibited the binding of anti-PLA2R IgG to podocytes and reduced the cellular injuries.

Anti-Phospholipase A2 Receptor Antibody (Anti-PLA2R) Testing to the Rescue

Serological testing for M-type anti-phospholipase A2 receptor antibodies (antiPLA2R Ab) has abrogated the need for kidney biopsy to diagnose membranous nephropathy in the appropriate clinical setting. We report a case of a 63-year-old hypertensive male who presented with nephrotic syndrome associated with autosomal dominant polycystic kidney disease which was effectively diagnosed with the use of antiPLA2R Ab test. He achieved complete remission upon treatment with Rituximab. Hitherto, all anecdotal case reports of this uncommon association were diagnosed only by kidney biopsy. We highlight the usefulness of PLA2RAb especially in such cases of difficult-to-biopsy kidneys.

#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 &amp;gt;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.

Preference for anti-phospholipase A2 receptor antibody assay in patients with suspected membranous nephropathy: a survey study on medical practice after publication of Japanese Guidelines for Nephrotic Syndrome 2020.

International practice guidelines advocate for the use of anti-phospholipase A2 receptor (PLA2R) antibody testing to diagnose primary membranous nephropathy (pMN). This study aimed to clarify the current status of anti-PLA2R antibody testing in the diagnosis of pMN in Japan and to scrutinize the factors associated with the implementation of this antibody test. Utilizing a web-based questionnaire for nephrologists, responses were collected from 306 facilities and 427 nephrologists between November 2021 and December 2021. Preference for anti-PLA2R antibody testing was also investigated. Factors related to the experience of quantifying anti-PLA2R antibodies were estimated by generalized estimating equations using a robust analysis of variance with clusters of facilities of affiliation. Of the 427 respondents, 140 (32.8%) had previous measurement experience at their current workplace and 165 (38.6%) had previous measurement experience overall. In pMN-suspected cases without contraindications to renal biopsy, 147 (34.4%) of the respondents opted to request anti-PLA2R antibody testing. The respondents' experience with anti-PLA2R antibody quantification at their current place of work was generally higher in university hospitals and increased with the annual number of kidney biopsies and the number of years since graduation. The results of this study suggest that a significant proportion of nephrologists in Japan have no experience in performing anti-PLA2R antibody assays, and that the assays may be hampered by the limited capabilities of the current workplace and the financial burden on facilities and patients.

Comparison of the efficacy of steroid-free versus classic steroid-containing regimens in primary membranous nephropathy.

Objective: To compare the efficacy of a steroid-free regimen with steroid-based treatment in managing primary membranous nephropathy (PMN) and investigate the potential benefits of steroid-free regimens in PMN therapy. Methods: This was a single-centre prospective cohort study. A total of 81 patients were divided into two groups according to their medication regimen: a rituximab (RTX)/tacrolimus (TAC) group (low-dose RTX combined with low-dose TAC group, without steroids, n = 31) and a prednisone (P)/TAC group (P combined with TAC group, n = 61). The changes in 24-h urine protein quantification, levels of blood albumin, blood creatinine, total cholesterol, triglyceride and fasting blood glucose as well as anti-phospholipase A2 receptor antibody titres were observed in both groups before treatment and after 1, 3, 6 and 12months of treatment. Clinical remission (complete and partial remission), serological remission and recurrence were assessed in both groups after treatment, and the occurrence of adverse reactions was observed. Results: 1) Before treatment, there was no significant difference in baseline values between the two groups (p > 0.05). 2) After 12months of treatment, the 24-h proteinuria and total cholesterol levels in the RTX/TAC group were significantly lower than those in the P/TAC group (p < 0.05). 3) After 6months of treatment, the clinical remission rate of the RTX/TAC group was significantly higher than that of the P/TAC group (p < 0.05). After 12months of treatment, the clinical remission rate of the RTX/TAC group was significantly higher than that of the P/TAC group (p < 0.05). (4) After 3, 6 and 12months of treatment, serological remission rates in the RTX/TAC group were significantly higher than those in the P/TAC group (p < 0.05). During treatment, the anti-PLA2R antibody titres in the RTX/TAC group remained lower than those in the P/TAC group (p < 0.05). Conclusion: The low-dose RTX combined with low-dose TAC steroid-free regimen induces serological remission in patients with PMN earlier than the classic regimen of P combined with TAC, and there was no significant difference in adverse effects between the two groups. Besides, the long-term clinical remission effect of low-dose RTX combined with low-dose TAC is better than that of P combined with TAC.

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

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

The cutoff value and prognosis of anti-PLA2R antibody for idiopathic membranous nephropathy: a single-center retrospective study in China

Serum anti-phospholipase A2 receptor (anti-PLA2R) antibody is used for the noninvasive diagnosis of idiopathic membranous nephropathy (IMN). However, the cutoff value of anti-PLA2R antibodies in IMN patients is debatable. This study aimed to investigate the cutoff value of anti-PLA2R antibodies for diagnosing IMN and the correlation of anti-PLA2R antibodies with clinical parameters and prognosis. A total of 252 IMN patients and 521 non-IMN patients with both renal biopsy and serum anti-PLA2R antibody data from April 2017 to November 2019 were enrolled. Anti-PLA2R antibody was detected by an enzyme-linked immunosorbent assay. The anti-PLA2R antibody titer was higher in the IMN group than in the non-IMN group (153.1 ± 22.4 vs. 2.0 ± 0.2 RU/mL, p < 0.001). The optimal anti-PLA2R antibody cutoff value for diagnosing IMN was 2.5 RU/mL, with a sensitivity, specificity, and Youden index of 85.7%, 88.3%, and 0.740, respectively. There was a significant positive correlation between anti-PLA2R antibody and 24-h urinary protein levels (r = 0.341, p < 0.001), and a significant negative correlation between anti-PLA2R antibody and serum albumin levels (r=−0.274, p < 0.001) in patients with IMN. The remission rates positively correlated with the immunosuppressive usage rates and increased from the low- to the high-titer subgroup. Multivariable Cox regression analysis showed that immunosuppressive therapy (adjusted HR = 4.656; 95% confidence interval [CI], 1.461–14.839; p = 0.009) was associated with a higher remission rate in patients with IMN. The optimal Anti-PLA2R antibody cutoff value for diagnosing IMN was 2.5 RU/mL, which was much lower than that indicated by the manufacturer. If IMN is actively treated, patients can have much better prognoses. Trial registration: retrospectively registered.

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.

Pharmacogenetic testing improves treatment responses in patients with PLA2R-related membranous nephropathy

To evaluate the value of pharmacogenetic testing for improving the efficacy and safety of treatment with cyclosporine, tacrolimus, and cyclophosphamide (CTX) for PLA2R-related membranous nephropathy and for determing individualized and precise treatment plans for the patients. A total of 63 patients with PLA2R-related membranous nephropathy hospitalized in the Department of Nephrology at our hospital from January, 2019 to October, 2021 were enrolled in this study. Thirty-three of the patients underwent pharmacogenetic testing before taking the immunosuppressive drugs selected based on the results of genetic screening for sensitive targets, and the other 30 patients were empirically given immunosuppressive drugs according to the guidelines (control group). The clinical efficacy and adverse effects of the immunosuppressive drugs were analyzed for all the patients. The two groups of patients were compared for demographic and biochemical parameters including 24-h urine protein, serum albumin, renal function, and serum anti-phospholipase A2 receptor antibody both before and at 3 months after the beginning of the treatment. Among the 33 patients undergoing pharmacogenetic testing, 51.5% showed a GG genotype for cyclosporine, and 61.6% had an AG genotype for tacrolimus; for CTX, 51.5% of the patients showed a homozygous deletion and 63.6% had an AA genotype. After treatment for 3 months, serum anti-phospholipase A2 receptor antibody, 24-h urine protein, and serum albumin levels were significantly improved in pharmacogenetic testing group as compared with the control group (P < 0.05). Individualized and precise administration of immunosuppressive drugs based on pharmacogenetic testing better controls proteinuria and serum antiphospholipase A2 receptor antibodies and increases serum albumin level in patients with PLA2R-related membranous nephropathy.

#3418 DISAPPEARANCE OF GLOMERULAR C3 DEPOSITION MIGHT BE A PROGNOSTIC MARKER IN MEMBRANOUS NEPHROPATHY AFTER TREATMENT

Abstract Background and Aims Membranous nephropathy (MN) is the most common cause of nephrotic syndrome (NS) in adults. In about 80% is primary and remaining 20% are secondary due to medications or other diseases. Treatment of primary MN remains controversial, and the prognosis is still difficult to predict despite the introduction of anti phospholipase A2 receptor (PLA2R) antibody. We evaluated pathological changes for predicting prognosis in patients of MN after methyprednisolone (MPD) pulse therapy. Method We performed 1,649 renal biopsies at the OPD during last 9 years, of which 31 subjects were MN. We performed follow up biopsy who showed normal urinary findings after treatment with MPD pulse therapy in 11 subjects of MN. Indications of the initial biopsy in MN were oral steroid resistant NS (9 subjects), massive proteinuria associated with hematuria (2 subjects). Among the 11 subjects of MN, 3 subjects were lupus nephritis (LN), 8 subjects were primary MN. One cycle of MPD consist of 10-20 mg/kg (max 1.0 g)/day for 3 consecutive days, performing every 10 to 14 days. Mean MPD pulse therapy were done 13 cycles Results Among the 11 cases of MN, male to female ratio was 6 to 5. Age distribution from 1 year old to 61years old (mean 40.8 y/o), Mean spot urine protein to creatinine before treatment was 4,182.5 mg/g and 189.4 mg/g after treatment. 9 subjects showed glomerular C3 deposition were noted at the initial biopsy and 2 subjects showed no C3 deposition. After treatment glomerular C3 deposition were disappeared in 8 subjects, and showed no relapse during 5.3 years follow up. However, 3 subjects who showed glomerular C3 deposition were lupus nephritis, relapsed during follow up period. Conclusion MPD pulse therapy might be still promising therapeutic modality in conventional oral steroid resistant MN. Although further larger number of studies are mandatory, disappearance of glomerular C3 deposition might be a prognostic marker for treatment response, instead of disappearance of proteinuria in MN.

#6227 SPONTANEOUS REMISSION OF MEMBRANOUS VARIANT OF PGNMID WITH MONOCLONAL IGG2κ

Abstract Background and Aims The clinical significance of the morphological patterns of glomerular injury and of each IgG subclass in proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (PGNMID) is not well understood. Literature suggests that PGNMID with certain histological features such as membranous or mesangio-proliferative features or non-IgG3 subclass staining may be associated with a more favourable renal prognosis. We present a patient with membranous variant of PGNMID with monoclonal IgG2κ who had spontaneous remission without recurrence over a 2-year follow-up. Method Not applicable Results A 62-year-old Malay gentleman presented with new onset nephrotic range proteinuria, on a background of type 2 diabetes mellitus with diabetic duration of 5 years, hypertension and hyperlipidemia. He was mildly hypertensive (blood pressure 148/87) and non-edematous at presentation. Investigations revealed preserved kidney function [serum creatinine (sCr) 66µmol/L], bland urinalysis, and 24-hour urinary total protein (UTP) of 3.74g/day. Serum albumin (sAlb) was 35g/L. Serum complements were not low. Autoimmune markers inclusive of anti-double stranded DNA antibodies, anti-neutrophil cytoplasmic antibodies, and anti-phospholipase A2 receptor (PLA2R) antibodies were negative. Viral serologies were also unremarkable. No monoclonal band was detected on serum electrophoresis, while serum immunofixation was not performed. Kidneys were normal sized. Renal biopsy performed demonstrated 28 glomeruli, of which only 1 was globally sclerosed. Glomeruli capillary walls were diffusely thickened by vacuolations. Capillary loops were mostly single contoured although occasional focal double contouring was seen. Masson trichome stain revealed fuchsinophilic subepithelial immune deposits while periodic acid methenamine silver stain showed argyrophilic basement membrane spikes. Variable mesangial expansion and hypercellularity was observed, as well as mesangiolysis. Focal leukocyte margination was present, but significant endocapillary proliferation was not seen. There were no Kimmelstiel-Wilson lesions. Tubular atrophy with interstitial fibrosis was overall mild (10% of parenchymal area) and there were no tubulointerstitial infiltrates. Immunofluoresence showed granular staining of IgG (1-2+), C3 (2-3+) along glomerular capillary walls, as well as presence of kappa light chain restriction (κ 1-2+; λ negative in glomeruli). Immunostaining for PLA2R was negative. IgG subclass analysis performed in view of kappa restriction revealed isolated deposition of IgG2. Electron microscopy was not available. Overall findings were most consistent with membranous variant of PGNMID with monoclonal IgG2κ. Age-appropriate and symptom-directed malignancy screening did not reveal significant abnormalities. Given that the patient was minimally symptomatic, a trial of conservative therapy was initiated with optimized non-immunosuppressive anti-proteinuric therapy using renin-angiotensin-aldosterone and sodium-glucose co-transporter-2 inhibitors. Gradual spontaneous remission was observed without recurrence over 2 years of follow-up (sCr 77µmol/L; sAlb 40g/L; 24-hour UTP 0.22g/day). Conclusion Our case adds to the literature that a membranous variant of PGNMID with monoclonal IgG2κ may be associated with better renal outcomes. Despite the lack of proliferative changes, it is possible that membranous variants may share similar underlying disease mechanisms as the other proliferative variants. Large international registries to allow the correlation of morphological features and IgG subclasses with clinical outcomes are required to confirm our observation.

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&lt;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.

Elevated plasma interleukin 21 is associated with higher probability and severity of idiopathic membranous nephropathy

Abstract Objectives Interleukin 21 (IL-21) is a receptor participating in innate immunity and correlates with the activation of innate immune cells. We sought to investigate the role of plasma IL-21 in patients with idiopathic membranous nephropathy (IMN). Methods This was a cross-sectional and case-control study. We analyzed plasma IL-21 in patients with IMN, with other kidney diseases as the diseased controls (DCs), and the healthy controls (HCs), regarding their associations with the risk of having IMN and IMN severity. Results We enrolled 132, 22, and 38 patients with IMN, DC, and HC, respectively. Plasma IL-21 was significantly higher in those with IMN [9.42 (6.93, 12.60)] and DC [7.84 (2.90, 7.95)] compared with HC [5.60 (2.90, 7.10)] (p&lt;0.05). Plasma IL-21 was significantly higher in those with IMN stage III [10.36 (6.94, 20.88)] and II [9.75 (7.60, 14.27)] than those with IMN stage I [6.99 (3.91, 9.08)] (p&lt;0.05). Plasma IL-21 was significantly higher in those with a positive anti-phospholipase A2 receptor antibody (PLA2R) [9.60 (8.27, 12.93)] than those with a negative anti-PLA2R antibody [4.84 (2.90, 11.28)] (p&lt;0.05). Receiver operator characteristic curve analysis showed that a cutoff value of 7.665 pg/mL distinguished patients with IMN from HC and DC with a sensitivity and specificity of 68.94 and 89.47 %, respectively, and the area under the curve was 0.8184. A cutoff value of 7.830 pg/mL identified those with IMN stage II with a sensitivity and specificity of 74.03 and 89.47 %, respectively, with an area under the curve of 0.8718 (p&lt;0.001). Multivariate regression showed that plasma IL-21 was positively correlated with anti-PLA2R and 24 h urine protein, and negatively correlated with total protein and serum albumin. Conclusions Plasma IL-21 levels increased significantly in patients with IMN. IL-21 may therefore serve as a biomarker for IMN.

Clinical characteristics and prognosis of patients with idiopathic membranous nephropathy with kidney tubulointerstitial damage

Background To investigate the clinical and kidney pathological features and prognosis of idiopathic membranous nephropathy (IMN) with kidney tubulointerstitial damage (TID). Methods Based on the presence or absence of kidney TID by kidney biopsy, 300 patients diagnosed with IMN were categorized into non-TID (TID−) and tubulointerstitial injury (TID+) groups. The clinical and pathological data were analyzed retrospectively. All patients were followed up for 6–24 months after treatment with glucocorticoids (GCs) combined with cyclophosphamide or GCs combined with calcineurin inhibitors (CNIs) to observe treatment effects on patient prognosis. Results The patients in the TID + group were older and more likely to be male. The 24-h urine protein, blood urea nitrogen, serum creatinine, cystatin C, β2-microglobulin, and antiphospholipase A2 receptor antibody levels were higher than those in the TID − group and the pathological manifestations were more severe. After 1 year of follow-up, the overall response rate (complete response + partial response) in the TID + group was lower (66.67% vs. 80.89%, p = .022) than in the other. After combined GC and CNI therapy, the complete remission rate in the TID + group was significantly lower than that in the TID − group (13.79% vs. 35.46%, p = .022). The 24-h urine protein level was an independent risk factor for worsening kidney condition (p = .038). Conclusion Patients with IMN with TID have more severe clinical manifestations and pathological damage and lower remission rates. IMN with TID is a risk factor for worsening kidney condition; however, it is not an independent risk factor.

Comparative analysis of the efficacy of different treatments for idiopathic membranous nephropathy: a retrospectively real-world study

Background This study aimed to explore the clinical efficacy of different treatment regimens for idiopathic membranous nephropathy (IMN). Methods Patients with IMN were retrospectively analyzed by dividing into two groups: glucocorticoids combined with cyclophosphamide group (GC + CYC) and glucocorticoids combined with calcineurin inhibitor group (GC + CNIs). After 1 year of treatment, those who found that the initial treatment was not effective were switched to another regimen. Patients continued to be followed up for at least 1 year to observe the treatment effects of different treatment regimens. Results This study found that the rate of complete and partial remission (CR + PR) in the GC + CYC and GC + CNIs groups was 76.19 vs. 82.63% after 1 year of follow-up (p > .05). In the GC + CYC and GC + CNIs groups, 27.78 and 11.95% of the patients switched treatment regimens, respectively. After 2 years of follow-up, the CR + PR rate was significantly higher in the change to GC + CNIs group after the switch compared to before the switch (80.00 vs. 31.43%, p < .001). It was also significantly higher in the change to GC + CYC group compared to before the switch (68.42 vs. 31.58%, p = .023). The recurrence rate was significantly higher in the maintain GC + CNIs and change to GC + CNIs groups than in the maintain GC + CYC and change to GC + CYC groups (25.14 vs 6.36%, p < .001). The disengagement rate from immunotherapy was significantly higher in the maintain GC + CYC group and the change to GC + CYC group than in the maintain GC + CNIs group and the change to GC + CNIs group (76.36% vs 29.71%, p < .001). High titer of anti-phospholipase A2 receptor (anti-PLA2R) antibody (95%CI: 0.199–0.947, p = .036) and serum C3 (95%CI: 0.030–0.570, p = .007) were independent risk factors, while serum IgG (95%CI: 1.000–1.331, p = .050) was a favorable factor for achieving CR. Anti-PLA2R antibody was the independent risk factor that affected the worse renal condition (p = .023). Conclusions Timely change of treatment regimen can significantly enhance therapeutic effect. Compared with patients administered with CYC, those administered with CNIs were less likely to leave treatment and had a higher recurrence rate.

The characters of antibodies against PLA2R in healthy individuals and in the patient with PLA2R associated membranous nephropathy

BackgroundMost primary membranous nephropathy (MN) is mediated by anti-phospholipase A2 receptor (PLA2R) antibodies. Recently, these antibodies have been revealed months to years before the disease's onset. Their production and pathogenicity need further investigation.MethodsAnti-PLA2R antibodies were purified from plasma of eight healthy individuals, 12 patients with PLA2R-related MN and negative circulating antibody (Ab-), and 18 patients with positive anti-PLA2R antibodies (Ab +), using affinity column coupled with recombinant human PLA2R. The antigen specificity, antibody amount, titer, IgG subclass, and affinity were assessed by Western blot, immunofluorescence, ELISA, and surface plasmon resonance.ResultsThe natural anti-PLA2R antibodies recognized the conformational structure of PLA2R which locates on the cell membrane of podocytes. The amount of natural IgG was 0.12 ± 0.04 g/L, which accounted for 0.80% of total IgG and was lower than that of patients (2.36%, P < 0.001). The titer of natural antibodies was lower than that of patients in Ab- and Ab + groups (1:16 vs. 1:43 vs. 1:274, P < 0.001). IgG2(45.1%) was predominant in natural antibodies, while IgG4 was predominant in Ab + group (45.7 vs. 25.0%, P < 0.001). IgG1 was increasing from natural antibodies to Ab- and Ab + groups. The affinity of natural antibodies was lower than that of patients (KD: 641.0 vs. 269.0 vs. 99.6 nM, P = 0.002). The antibody titer, affinity, and IgG4 percentage were associated with the severity of proteinuria and the stages of membranous lesion.ConclusionsThe natural anti-PLA2R antibodies exist in healthy plasma. The antibody titer, IgG subclass, and affinity may participate in the pathogenesis of anti-PLA2R antibodies.