Anti-CD20 Monoclonal Antibody (Rituximab) for the Treatment of Recurrent Idiopathic Membranous Nephropathy in a Renal Transplant Patient

Idiopathic membranous nephropathy (IMN) remains the most common histologic entity associated with adult-onset nephrotic syndrome. The therapy for IMN is challenging. Steroids and various other immunosuppressive agents have been tried in IMN; however, current agents have not altered the course of IMN, are nonspecific and can be very toxic. In native kidneys affected by IMN, rituximab, a monoclonal antibody against the B-cell surface antigen CD20, has been shown to reduce proteinuria and prevent disease progression. In this report, we describe a 39-year-old white male with end-stage renal disease secondary to IMN that, 4 months post living unrelated kidney transplant, developed recurrent IMN with 18 g/day of proteinuria. In addition to angiotensin converting enzyme inhibitor and statins, the patient was treated with 4 weekly doses of 375 mg/m2 of rituximab with significant reduction in proteinuria, a corresponding increase in serum albumin and improvement in hypercholesterolemia. At 3 years post-transplant, his kidney function remains stable with 0.5 g/day of proteinuria.     

Idiopathic membranous glomerulonephritis in Brazil

Summary: A survey of the medical records and renal biopsy reports of 41 patients with a diagnosis of membranous glomerulonephritis seen at the University Hospital, Faculty of Medicine of Ribeirão Preto, University of São Paulo was undertaken between 1961 and April 1992. Twenty-three of these patients were found to have idiopathic membranous glomerulonephritis (IMG) and 22 of them were treated with corticosteroids and/or immunosuppressants. Data for these 22 patients showed that the age at clinical presentation was 36.3± 17.5 years, white skin colour predominated (14 patients), and 15 were males; nephrotic syndrome was the clinical presentation in 20 patients and proteinuria was accidentally discovered in two patients. On the first hospital visit 11 patients presented proteinuria of up to 3 g/24 h and 16 presented serum creatinine below 1.5 mg/dL, and 14 developed renal hypertension during follow up. Clinicalmorphological correlation permitted us to conclude (in agreement with the literature) that advanced patient age, intensity of proteinuria, serum creatinine levels above 1.5 mg/dL on the occasion of the first hospital visit, and arterial hypertension are clinical-laboratory factors indicating a poor prognosis for IMG. More advanced staging of glomerular damage, presence of segmental mesangial sclerosis and tubulointerstitial involvement are microscopic factors indicating a poor prognosis for IMG.     

Recurrent Idiopathic Membranous Nephropathy After Kidney Transplantation: A Surveillance Biopsy Study

Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. MN can recur after kidney transplantation causing proteinuria, allograft dysfunction and graft failure. In this study we assessed the incidence of MN recurrence utilizing surveillance graft biopsies. The study included 1310 renal allograft recipients from 2000 to 2006. Glomerular diseases were the cause of kidney failure in 28% of patients and 23 (2%) had idiopathic MN. Recurrent MN was diagnosed in eight of 19 patients included in this analysis (42%) 13 ± 20 months (median = 4; range 2–61 months) after transplant. The initial clinical manifestations of recurrent MN were mild or absent. Urine protein excretion was 825 ± 959 (64–2286) mg/day and three patients had no proteinuria. Five of seven patients who did not receive additional immunosuppression for MN had significant increases in proteinuria during follow up and three became nephrotic. At diagnosis, light microscopic changes were subtle or absent. All patients had granular glomerular basement membrane deposits of IgG but little or absent C3 by immunofluorescence. Subepithelial deposits were observed in all cases by electron microscopy. In conclusion, idiopathic MN recurred in 42% of patients after transplantation. The initial clinical and histologic manifestations are subtle but the disease is progressive.     

Antibodies to m‐type phospholipase A2 receptor in children with idiopathic membranous nephropathy

Idiopathic membranous nephropathy (IMN), the commonest cause of adult nephrotic syndrome (NS), accounts for only a minority of paediatric NS. Antibodies to m‐type phospholipase A2 receptor (PLA2R) are seen in two‐thirds of adult IMN cases. PLA2R staining in glomerular deposits is observed in 74% and 45% of adult and paediatric IMN cases, respectively. However, there are no reports of anti‐PLA2R in paediatric IMN. We evaluated anti‐PLA2R levels and PLA2R in gloemrular deposits in paediatric IMN seen at our center. Five cases were enrolled, all the cases stained for PLA2R in glomeruli and three (60%) had antibodies to PLA2R antigen. There was a parellel reduction in proteinuria and anti‐PLA2R titer. The present report suggests that PLA2R has a contributory role in the pathogenesis of paediatric IMN.     

Anti-Phospholipase A2 Receptor Antibody Titer Predicts Post-Rituximab Outcome of Membranous Nephropathy

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/m²) 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.     

New ‘Antigens’ in Membranous Nephropathy

Membranous nephropathy (MN) occurs due to deposition of immune complexes along the subepithelial region of glomerular basement membrane. Two previously identified target antigens for the immune complexes, PLA2R (identified in 2009) and THSD7A (in 2014), account for approximately 60% of all MN, both primary and secondary. In the remaining MN, target antigens were unknown. Use of laser microdissection and mass spectrometry enabled identification of new “antigens.” This approach led to the identification of four novel types of MN: exotosin 1 (EXT1)– and exotosin 2 (EXT2)–associated MN, NELL1-associated MN, Sema3B-associated MN, and PCDH7-associated MN. Each of these represents a distinct disease entity, with different clinical and pathologic findings. In this review, the structure of the proteins and the clinical and pathologic findings of the new types of MN are discussed. The role of mass spectrometry for accurate diagnosis of MN cannot be overemphasized. Finally, any classification of MN should be made on the basis of the antigens that are detected. Further studies are required to understand the pathophysiology, response to treatment, and outcomes of these new MNs.     

Serine Protease HTRA1 as a Novel Target Antigen in Primary Membranous Nephropathy

Open in a separate window     

环孢霉素A与环磷酰胺联合激素治疗膜性肾病的疗效比较

目的：比较环孢霉素A（CSA）与环磷酰胺（CTX）联合激素治疗成年人特发性膜性肾病（IMN）的疗效和安全性。方法：76例原发性肾病综合征患者经肾活检确诊为IMN,在诊断上排除了继发性膜性肾病,单用激素治疗无效或复发,随机分两组分别予CSA联用糖皮质激素治疗（CSA组）或CTX联用糖皮质激素治疗（CTX组）,疗程至少12个月。观察各组的24h尿蛋白定量、血浆白蛋白、肾功能、血糖、白细胞总数及其不良反应,以及治疗前后的完全缓解率、部分缓解率。全部患者且在正式进入研究治疗前未用或已停用类固醇激素和细胞毒药物达半年以上。结果：治疗3个月末,CsA组的24h尿蛋白、胆固醇、三酰甘油显著低于CTX组（P均〈0.01）,血清白蛋白显著高于CTX组（P〈0.01）。两组患者的血肌酐比较差异无统计学意义（P〉0.05）,而CTX组的WBC显著低于CsA组（P〈0.01）。CsA组完全缓解率显著高于CTX组（χ2=4.6317,P〈0.05）。治疗12个月末两组的完全缓解率差异无统计学意义（χ2=1.2575,P〉0.05）。CsA组的不良反应发生率（8/40=20.0%）显著低于CTX组（15/36=41.7%）（χ2=4.2146,P〈0.05）。结论：与CTX相比,CsA联用糖皮质激素对IMN治疗12个月的总体疗效相当,但CsA起效更快,近期疗效更好,不良反应更小。CsA≤5mg.kg-1.d-1用于肾功能正常IMN患者是安全有效的。     

成人特发性膜性肾病遗传易感性与中医证型的关联性研究

目的:探讨特发性膜性肾病(IMN)的足细胞裂隙隔膜相关蛋白基因NPHS1、NPHS2与中医辨证分型的关联。方法:收集原发性肾病综合征患者200例,其中实验组(IMN)38例,对照组(非IMN)162例,两组病人外周血淋巴细胞中获得基因组DNA进行序列分析、测定,分析NPHS1基因G349A位点、NPHS2基因G686A,C695T位点的多态性及其与中医证型关联。结果:(1)两组年龄分布差异有统计学意义(P<0.05);(2)两组NPHS1基因G349A位点基因型频率分布差异有统计学意义(P<0.05)。实验组纯合突变AA基因型频率明显高于对照组;杂合突变GA基因型频率明显低于对照组;(3)两组NPHS2基因G686A,C695T位点未发现多态性改变;(4)两组中医证型本虚证中气(阳)虚证、阴虚证差异有统计学意义(P<0.05);两组标实证中湿热证和血瘀证差异有统计学意义(P<0.05)。(5)未发现候选基因多态性与中医辨证分型的明显相关性。结论:在PNS患者中IMN患者年龄偏大。NPHS1基因G349A位点基因型AA与IMN发病有相关性。IMN中医证型气(阳)虚证、血瘀证明显多于非IMN患者,阴虚证、湿热证明显少于非IMN患者。未发现候选基因多态性与中医辨证分型的明显相关性。     

The bias between different albumin assays may affect clinical decision-making

1. Download : Download high-res image (338KB)
2. Download : Download full-size image

     

来氟米特与环磷酰胺治疗膜性肾病的疗效比较

目的：评价来氟米特（LEF）与环磷酰胺（CTX）分别联合泼尼松（PED）治疗成年人特发性膜性肾病（IMN）的疗效及安全性。方法：80例原发性肾病综合征患者经肾活检确诊为IMN,在诊断上排除了继发性膜性肾病,随机分两组：LEF组40例采用LEF＋PED治疗,CTX组40例采用CTX＋PED治疗。治疗期间及治疗前后,监测血常规、尿常规、24h尿蛋白定量、血白蛋白、血脂、肝肾功能,6个月后行疗效和安全性的评价。结果：（1）LEF组40例中失访1例,完成6个月治疗39例。CTX组40例中因不耐受药物不良反应中途退出7例,完成6个月治疗33例;（2）治疗3个月后LEF组的完全缓解率显著低于CTX组（χ2=4.3516,P〈0.05）,LEF组的未缓解显著高于CTX组（χ2=4.9059,P〈0.05）;治疗6个月后两组的完全缓解率、未缓解率差异无统计学意义（P均〉0.05）;（3）治疗6个月后,两组患者的24hUpro、Alb、TC、TG均较治疗前显著改善（LEF组：t=7.0841,9.0998,8.4412,7.7942;CTX组：t=8.7823,9.2826,7.1252,6.9731,P均〈0.01）,CTX组的改善略微优于LEF组（t=1.8112,1.6780,0.9881,1.6778,P均〉0.05）,但差异均无统计学意义;（4）CTX组中因不良反应中途退出的比率（7/40）显著高于LEF组（0/40）,（χ2=5.6360,P〈0.05）;LEF组不良反应发生率（5/39）显著低于CTX组（13/40）,（χ2=4.3468,P〈0.05）,差异均有统计学意义。结论：来氟米特治疗膜性肾病,与环磷酰胺的临床疗效相似,不良反应较少,但起效稍慢。     

Remission of De Novo Membranous Nephropathy in a Kidney Allograft Recipient: a Case Report

Membranous nephropathy (MN), one of the most frequent causes of nephrotic syndrome in native kidneys, is also a common glomerular pathology in transplanted kidneys(Davison AM, Johnston PA. Allograft membranous nephropathy, Nephrol Dial Transplant, 1992;7(Suppl. 1):114–118. Specific treatment modalities have not been described for this population. However, renal transplanted patients presented with MN could have spontaneous remission as those with idiopathic MN. Here, we report a kidney allograft recipient diagnosed with de novo MN in early phases of posttransplantation period having a clinical remission over months.     

Rituximab in Children with Steroid-Dependent Nephrotic Syndrome: A Multicenter,Open-Label,Noninferiority, Randomized Controlled Trial

Steroid-dependent nephrotic syndrome (SDNS) carries a high risk of toxicity from steroids or steroid-sparing agents. This open-label, noninferiority, randomized controlled trial at four sites in Italy tested whether rituximab is noninferior to steroids in maintaining remission in juvenile SDNS. We enrolled children age 1–16 years who had developed SDNS in the previous 6–12 months and were maintained in remission with high prednisone doses (≥0.7 mg/kg per day). We randomly assigned participants to continue prednisone alone for 1 month (control) or to add a single intravenous infusion of rituximab (375 mg/m²; intervention). Prednisone was tapered in both groups after 1 month. For noninferiority, rituximab had to permit steroid withdrawal and maintain 3-month proteinuria (mg/m² per day) within a prespecified noninferiority margin of three times the levels among controls (primary outcome). We followed participants for ≥1 year to compare risk of relapse (secondary outcome). Fifteen children per group (21 boys; mean age, 7 years [range, 2.6–13.5 years]) were enrolled and followed for ≤60 months (median, 22 months). Three-month proteinuria was 42% lower in the rituximab group (geometric mean ratio, 0.58; 95% confidence interval, 0.18 to 1.95 [i.e., within the noninferiority margin of three times the levels in controls]). All but one child in the control group relapsed within 6 months; median time to relapse in the rituximab group was 18 months (95% confidence interval, 9 to 32 months). In the rituximab group, nausea and skin rash during infusion were common; transient acute arthritis occurred in one child. In conclusion, rituximab was noninferior to steroids for the treatment of juvenile SDNS.     

Protocadherin 7–Associated Membranous Nephropathy

BackgroundMembranous nephropathy (MN) results from deposition of antigen-antibody complexes along the glomerular basement membrane (GBM). PLA2R, THSD7A, NELL1, and SEMA3B account for 80%–90% of target antigens in MN.MethodsWe performed laser microdissection and mass spectrometry (MS/MS) in kidney biopsies from 135 individuals with PLA2R-negative MN, and used immunohistochemistry/immunofluorescence and confocal microscopy to confirm the MS/MS finding, detect additional cases, and localize the novel protein. We also performed MS/MS and immunohistochemistry on 116 controls and used immunofluorescence microscopy to screen biopsy samples from two validation cohorts. Western blot and elution studies were performed to detect antibodies in serum and biopsy tissue.ResultsMS/MS studies detected a unique protein, protocadherin 7 (PCDH7), in glomeruli of ten (5.7%) PLA2R-negative MN cases, which also were negative for PLA2R, THSD7A, EXT1/EXT2, NELL1, and SEMA3B. Spectral counts ranged from six to 24 (average 13.2 [SD 6.6]). MS/MS did not detect PCDH7 in controls (which included 28 PLA2R-positive cases). In all ten PCDH7-positive cases, immunohistochemistry showed bright granular staining along the GBM, which was absent in the remaining cases of PLA2R-negative MN and control cases. Four of 69 (5.8%) cases in the validation cohorts (all of which were negative for PLA2R, THSD7A, EXT1, NELL1, and SEMA3B) were PCDH7-positive MN. Kidney biopsy showed minimal complement deposition in 12 of the 14 PCDH7-associated cases. Confocal microscopy showed colocalization of PCDH7 and IgG along the GBM. Western blot analysis using sera from six patients showed antibodies to nonreduced PCDH7. Elution of IgG from frozen tissue of PCDH7-associated MN showed reactivity against PCDH7.ConclusionsMN associated with the protocadherin PCDH7 appears to be a distinct, previously unidentified type of MN.