[Changes of urinary monocyte chemotactic protein 1 and epidermal growth factor and their correlations with clinicopathology in idiopathic membranous nephropathy patients].

Objective: To explore the changes and clinical value of urinary monocyte chemotactic protein 1 (MCP-1), epidermal growth factor (EGF) and their ratio in patients with idiopathic membranous nephropathy (IMN). Methods: A total of 67 IMN patients were enrolled according to kidney biopsy in the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2018. The patients included 28 males and 39 females, with an average age of (47.6±14.2) years. Eighteen age-and sex-matched healthy controls were also enrolled. Clinical and pathological data, blood and urine samples of all subjects were collected. Urinary MCP-1 and EGF level were detected by enzyme-linked immunosorbent assay (ELISA). And then the levels of urinary MCP-1, EGF and the ratio of EGF/MCP-1 and their correlations with clinicopathology were analyzed. Results: There was no statistical difference of the urine EGF levels between the two groups [8.3(6.0,12.6) vs 8.4(6.5,10.2) ng/mg Cr, P=0.575]. The urine MCP-1 levels of IMN patients were 0.37 (0.21, 0.69) ng/mg Cr, which was statistical significantly higher than those of the control group [0.09 (0.02, 0.19) ng/mg Cr] (P<0.001), while the EGF/MCP-1 ratio was lower than that of the control group [22.2(15.1,36.6) vs 87.6(71.2,132.7), P<0.001]. Urine MCP-1 was negatively correlated with eGFR (r=-0.303, P=0.012), but positively correlated with the urinary ratio of albumin to creatinin (r=0.368, P=0.002). EGF was positively correlated with eGFR (r=0.722, P<0.001), but negatively correlated with the severity of interstitial fibrosis and renal tubular atrophy (IFTA) (r=-0.312, P=0.011). EGF/MCP-1 ratio was positively correlated with eGFR (r=0.693, P<0.001), but negatively correlated with the severity of the urinary ratio of albumin to creatinin and IFTA (r=-0.261, P=0.028 and r=-0.684, P<0.001, respectively). Further multivariate logistic regression analysis showed that EGF/MCP-1 was a protective factor for moderate-to-severe IFTA (OR=0.891, 95%CI: 0.844-0.949, P=0.008). Conclusion: Patients with IMN have elevated urine MCP-1 level and decreased EGF/MCP-1 ratio, which correlate with clinical indicators. In particular, EGF/MCP-1 ratio is independently related to moderate-severe IFTA, and may be a potential clinical biomarker for diagnosis of IMN.

Analysis of predictive factors for immunosuppressive response in anti-phospholipase A2 receptor antibody positive membranous nephropathy.

BACKGROUND: Serum anti-phospholipase A2 receptor (PLA2R) antibody was correlated with disease activity of membranous nephropathy(MN). The predictive value of antibody titer changes on immunosuppressive response remains unknown. We investigated predictive value of dynamic change of anti-PLA2R antibody and 24-h urine protein (24hUP) for clinical response of MN. METHODS: This was a retrospective cohort study including 47 Chinese MN patients with positive anti-PLA2R antibody in a tertiary referral hospital between January 2012 and March 2014. Patients received cyclophosphamide (CTX, n = 23), or cyclosporine (CYA, n = 24) regimen, respectively. We monitored serum anti-PLA2R titer and 24hUP at one, three and six-month follow-up. RESULTS: At baseline, total patients were 42 ± 14 years old with 29/18 male/female ratio. The median 24hUP was 5.80(3.56,9.41) g/d. The median baseline anti-PLA2R antibody titer was 66.4(31.9, 188.0) RU/mL. Baseline 24hUP and eGFR between subgroups were not significantly different. The differences of relative reduction between antibody titer and 24hUP at one month were statistically significant (CTX group 94.2% vs. 46.8%, P < 0.001; CYA group 54.6% vs. 4.6%, P = 0.04). Only in CTX group, the relative reduction of 24hUP at one month was correlated with composite remission at six-month(P = 0.03). Area under the curve of 24hUP relative reduction in CTX group at one-month for predicting composite remission at six months was 0.85(95%CI 0.65~1.05, P = 0.04). The cutoff value of one-month's 24hUP relative reduction for predicting six-month's composite remission in CTX group was 15.3%, with high sensitivity (83.3%) and specificity (100%). CONCLUSIONS: Compared with relative reduction of antibody titer, relative reduction of 24hUP at one-month follow-up in CTX group had a better predictive value for six-month's composite remission.

[Glomerulonephritides]. / Glomerulonephritiden.

Many forms of glomerulonephritis, even the more common types belong to the so-called rare diseases; however, they are very important, for example with respect to health economics as they often affect young people. An example is immunoglobulin A (IgA) nephropathy, which is the most common cause of end stage renal disease in young adults. This review summarizes the current knowledge on the pathogenesis, clinical presentation and therapy of the most common European types of glomerulonephritis with a special focus on the most recently acquired knowledge on IgA nephropathy, membranous glomerulonephritis, minimal change nephropathy and focal segmental glomerulosclerosis (FSGS).

Treatment of rituximab in patients with idiopathic membranous nephropathy: a case series and literature review.

BACKGROUND/AIMS: Membranous nephropathy (MN) is a major cause of nephrotic syndrome in adults. This study aimed to evaluate the effect of rituximab (RTX) in patients with idiopathic MN (iMN) who have a high risk of progression. METHODS: We retrospectively analyzed data of 13 patients with iMN, who received RTX treatments from January 2014 to July 2020. RTX was indicated in patients with iMN with severe proteinuria and decreasing estimated glomerular filtration rate (eGFR) in the previous 6 months despite other immunosuppressive therapies. RESULTS: The patients were predominantly males (n = 11) and with a mean age of 55.3 years; median eGFR, 37.0 mL/min/1.73 m2 (interquartile range [IQR], 26.3 to 66.5); serum albumin level, 2.6 g/dL (IQR, 1.9 to 3.1); and spot urine protein-to-creatinine ratio at baseline, 6.6 g/g (IQR, 5.7 to 12.9). In a median follow-up of 22 months, eight patients (61.5%) achieved complete or partial remission. In responder group (n = 8), median eGFR increased from 31.5 to 61.5 mL/min/1.73 m2 (p = 0.049) and serum albumin level increased from 2.3 to 4.2 g/dL (p = 0.017) from RTX initiation to last follow-up. Antiphospholipase A2 receptor antibody (anti-PLA2R-Ab) was positive in six among seven tested patients, which markedly decreased in the responder group. There were no adverse events after RTX. CONCLUSION: This study suggests that RTX is a safe and effective treatment option for patients with iMN who have a high risk of progression. Individualized therapy based on anti-PLA2R-Ab titer would be needed for better outcomes.

Clinical outcomes and effects of treatment in older patients with idiopathic membranous nephropathy.

BACKGROUND/AIMS: Membranous nephropathy (MN) is the most common primary glomerular disease diagnosed in older patients. Few reports describe the clinical outcomes in older patients with idiopathic MN. METHODS: The outcomes of 135 patients with histologically proven MN were analyzed. 'Older' was defined as 60 years of age or older at the time of the renal biopsy. The rates of complete remission (CR), progression to end-stage renal disease (ESRD) and infection were compared between older and younger patients. RESULTS: The cumulative event rate for achieving CR was inferior (p = 0.012) and that for requiring renal replacement was higher (p = 0.015) in older patients, and they had a greater risk of infection (p = 0.005). Older age was a significant predictor of a lower rate of CR (adjusted odds ratio [OR], 0.51; 95% confidence interval [CI], 0.26 to 0.98), and was a robust predictor of infection (adjusted OR, 5.27; 95% CI, 1.31 to 21.20). Conservative treatment was associated with a lower remission rate (p = 0.036) and corticosteroid treatment was less effective in achieving CR (p = 0.014), in preventing progression to ESRD (p = 0.013) and in reducing infection (p = 0.033) in older patients. Cyclosporine treatment had similar clinical outcomes with regard to CR, ESRD progression, and infection in older patients. CONCLUSION: Older age was independently associated with inferior rates of CR and greater risk of infection. Treatment modalities affected the outcomes of older patients differently in that cyclosporine treatment is predicted to be more useful than corticosteroids.

Sensitivity and Specificity of Pathologic Findings to Diagnose Lupus Nephritis.

BACKGROUND AND OBJECTIVES: In 2012, the Systemic Lupus International Collaborating Clinics proposed that lupus nephritis, in the presence of positive ANA or anti-dsDNA antibody, is sufficient to diagnose SLE. However, this "stand-alone" kidney biopsy criterion is problematic because the ISN/RPS classification does not specifically define lupus nephritis. We investigated the combination of pathologic features with optimal sensitivity and specificity for the diagnosis of lupus nephritis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Three hundred consecutive biopsies with lupus nephritis and 560 contemporaneous biopsies with nonlupus glomerulopathies were compared. Lupus nephritis was diagnosed if there was a clinical diagnosis of SLE and kidney biopsy revealed findings compatible with lupus nephritis. The control group consisted of consecutives biopsies showing diverse glomerulopathies from patients without SLE, including IgA nephropathy, membranous glomerulopathy, pauci-immune glomerulonephritis, membranoproliferative glomerulonephritis (excluding C3 GN), and infection-related glomerulonephritis. Sensitivity and specificity of individual pathologic features and combinations of features were computed. RESULTS: Five characteristic features of lupus nephritis were identified: "full-house" staining by immunofluorescence, intense C1q staining, extraglomerular deposits, combined subendothelial and subepithelial deposits, and endothelial tubuloreticular inclusions, each with sensitivity ranging from 0.68 to 0.80 and specificity from 0.8 to 0.96. The presence of at least two, three, or four of the five criteria had a sensitivity of 0.92, 0.8, and 0.66 for the diagnosis of lupus nephritis, and a specificity of 0.89, 0.95, and 0.98. CONCLUSIONS: In conclusion, combinations of pathologic features can distinguish lupus nephritis from nonlupus glomerulopathies with high specificity and varying sensitivity. Even with stringent criteria, however, rare examples of nonlupus glomerulopathies may exhibit characteristic features of lupus nephritis.

Caracterización de enfermedades glomerulares: análisis de 22 años de biopsias renales / Frequency of glomerular diseases in an analysis of 550 kidney biopsies

BACKGROUND: The frequency of glomerular diseases is dynamic and varies according to geographic area. AIM: To evaluate the frequency of primary and secondary glomerulopathies, their demographic profile and main clinical characteristics. MATERIAL AND METHODS: Renal biopsies from native kidneys performed between 1999 and 2020 were retrospectively reviewed. Demographic characteristics, clinical presentation, most relevant laboratory tests, frequency of primary and secondary glomerulopathies were analyzed. RESULTS: We analyzed 550 kidney biopsies from patients with a median age of 48 years (64% females). Nephrotic syndrome was the main indication for renal biopsy. Primary and secondary glomerulopathies occurred with similar frequency. Within the primary glomerulopathies, membranous nephropathy (34.1%) was the most common, followed by IgA nephropathy (31.1%) and focal segmental glomerulosclerosis (14.1%). Among the secondary glomerulopathies, lupus nephropathy was the most common (41.7%), followed by pauciimmune glomerulonephritis (27.1%) and diabetic nephropathy (6.4%). When comparing the results with other regions, significant differences were observed with reported frequencies in United States, Europe, Asia and the rest of Latin America. CONCLUSIONS: The most common primary glomerulopathies were membranous nephropathy and IgA nephropathy. Among the secondary glomerulopathies lupus nephropathy and pauci-immune glomerulonephritis were the most common. Compared to international registries, we observed a high proportion of membranous nephropathy and pauci-immune glomerulonephritis.

The Spectrum of Biopsy-Proven Glomerular Diseases among Children in China: A National, Cross-Sectional Survey.

BACKGROUND AND OBJECTIVES: High-quality epidemiologic data on the spectrum of biopsy-proven glomerular diseases among children are limited. This study aimed to determine the profile of and temporal change in biopsy-proven pediatric glomerular diseases in China. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We previously conducted a nationwide kidney biopsy survey including 71,151 patients over an 11-year period from January 2004 to December 2014. A total of 7962 children younger than 18 years old from 115 hospitals across China with biopsy-proven glomerular diseases were included in this study. The demographic and clinical variables were extracted from referral records and pathology reports. The composition of pediatric glomerular diseases and clinicopathologic correlations in different sexes, age groups, and regions were assessed. The changing patterns of common glomerulopathies over the study period were examined. RESULTS: Nephrotic syndrome (50%) was the most frequent indication for kidney biopsy in children. Minimal change disease was the most common primary glomerular disease (29%) followed by IgA nephropathy (17%). Henoch-Schonlein purpura nephritis (13%) and lupus nephritis (9%) were the most common secondary glomerular diseases. The proportion of minimal change disease was significant higher in boys (38%) than in girls (13%), whereas lupus nephritis was more prevalent in girls (20%) than in boys (3%). Purpura nephritis (23%) was the major pathologic pattern in younger children (0-12 years old), whereas minimal change disease (33%) was the most common glomerulopathy in adolescents (13-18 years old). The clinicopathologic correlations were slightly different between sexes and age groups. We observed increases in the proportions of minimal change disease, purpura nephritis, and membranous nephropathy over the study period that were contemporaneous with a fall in the proportion of FSGS. CONCLUSIONS: The spectrum of glomerular diseases among children varied across sexes, age groups, and regions and changed substantially from 2004 to 2014 in China.

Urinary Fibrinogen as a Predictor of Progression of CKD.

BACKGROUND AND OBJECTIVES: Fibrinogen has been reported to be involved in kidney tubulointerstitial fibrosis and podocyte injury in mouse models. However, the relationship between urinary fibrinogen and kidney outcomes has not been clarified in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We evaluated 402 patients with CKD and kidney biopsies, including 101 with diabetic nephropathy, 94 with idiopathic membranous nephropathy, 55 with idiopathic FSGS, and 152 with IgA nephropathy. We quantified urinary fibrinogen by ELISA and tested associations with kidney histology and progression to ESRD. RESULTS: Median (interquartile range) urinary fibrinogen-to-creatinine ratio was 536 (191-1461) ng/mg for patients with CKD, significantly higher than 2 (2-3) ng/mg for healthy controls (P<0.001). Urinary fibrinogen was positively correlated with urine protein (r=0.64; P<0.001) and interstitial fibrosis and tubular atrophy (r=0.10; P=0.04), and it was negatively correlated with eGFR (r=-0.20; P<0.001). Over a median follow-up period of 35 months (interquartile range, 24-78 months), 68 of 402 patients (17%) developed ESRD. Higher urinary fibrinogen level was associated with increased risk of ESRD (hazard ratio, 2.12; 95% confidence interval, 1.31 to 3.26) per log10 higher urinary fibrinogen-to-creatinine ratio (P=0.003) adjusting for age, sex, BP, urine protein, disease type, eGFR, and interstitial fibrosis and tubular atrophy. For prediction of ESRD, the addition of urinary fibrinogen to eGFR, urine protein, and BP increased the area under the receiver operating curve from 0.73 to 0.76, and the Akaike information criterion improved from 333.6 to 327.0. CONCLUSIONS: Urinary fibrinogen correlated with interstitial fibrosis and tubular atrophy and was an independent risk factor for progression of CKD to ESRD.

Prevalencia del anticuerpo anti receptor de fosfolipasa A2 sérico e histológico en pacientes con nefropatía membranosa en un Centro Universitario / Phospholipase A2 receptor antigen antibodies in serum and renal biopsies of patients with membranous nephropathy

BACKGROUND: The discovery of the phospholipase A2 receptor antigen and its highly specific autoantibody (anti-PLA2R Ab) was useful for the diagnosis and follow-up of patients with membranous nephropathy (MN). Thus, some international guidelines recommend not performing renal biopsy in patients with positive serum anti-PLA2R Ab. Aim: To evaluate the prevalence of anti-PLA2R Ab in serum and renal tissue samples from Chilean patients with primary MN. MATERIAL AND METHODS: Twenty-eight patients aged 50 ± 14 years (20 males) with biopsy-proven primary MN plus a negative workup for secondary causes were included. Measurements of serum and renal histologic anti-PLA2R Ab were performed. The relationship between the findings of serum and tissue anti-PLA2R Ab was evaluated. RESULTS: Fifteen patients (54 %) had anti-PLA2R Ab presence in serum and 19 patients (68%) had positive anti-PLA2R Ab in the renal biopsy. All patients with positive serum anti-PLA2R Ab had positive antibodies on immunohistochemistry. Conclusions: Serum anti-PLA2R Ab is potentially useful in the diagnosis of patients with suspected primary MN in Chilean population.

Overview of IgG4-Related Tubulointerstitial Nephritis and Its Mimickers.

Tubulointerstitial nephritis (TIN) is the most common form of renal involvement in IgG4-related disease. It is characterized by a dominant infiltrate of IgG4-positive plasma cells in the interstitium and storiform fibrosis. Demonstration of IgG4-positive plasma cells is essential for diagnosis, but the number of IgG4-positive cells and the ratio of IgG4-positive/IgG-positive plasma cells may vary from case to case and depending on the methods of tissue sampling even in the same case. IgG4-positive plasma cells can be seen in TIN associated with systemic lupus erythematosus, Sjögren syndrome, or anti-neutrophil cytoplasmic antibody-associated vasculitis, which further add diagnostic confusion and difficulties. To have a more clear view of IgG4-TIN and to delineate differential points from other TIN with IgG4-positive plasma cell infiltrates, clinical and histological features of IgG4-TIN and its mimickers were reviewed. In the rear part, cases suggesting overlap of IgG4-TIN and its mimickers and glomerulonephritis associated with IgG4-TIN were briefly described.

Gastric Syphilis and Membranous Glomerulonephritis.

Syphilis is a chronic systemic infectious disease caused by the bacterium Treponema pallidum. Gastric involvement and nephrotic syndrome are uncommon but well documented complications of syphilis, but the co-occurrence of these two complications in the same patient is extremely rare. Thus, because of their nonspecific presentation, suspicion of gastric syphilis (GS) and nephrotic syndrome is essential for diagnosis. Patients should be investigated thoroughly and a diagnosis made based on clinical, endoscopic, and histological findings, in order to initiate appropriate therapy. We report of a 34-year-old male patient with a history of epigastric pain and a diagnosis of GS and syphilis-associated membranous glomerulonephritis confirmed by gastroscopy and kidney biopsy, who was treated successfully with penicillin G benzathine. This case report provides information on the typical features of GS that should help raise awareness of this rare disease entity among clinicians, resulting in earlier diagnosis and administration of appropriate therapy.

Membranous nephropathy PLA2R+ associated with Chagas disease.

Chagas disease (CD) - a tropical parasitic disease caused by the protozoan Trypanosoma cruzi - is a major health problem in Latin America. The immune response against the parasite is responsible for chronic CD lesions. Currently, there are no reports of an association between CD and membranous nephropathy (MN). The detection of the phospholipase A2 receptor (PLA2R) as a target antigen in idiopathic MN can improve the differential diagnosis of primary and secondary forms of MN. The authors report the case of a male patient with positive serology for CD who presented sudden death and underwent autopsy. Histological sections of the heart showed multifocal inflammatory infiltrate composed mainly of mononuclear cells, leading to myocardiocytes necrosis and interstitial fibrosis. The kidneys showed a MN with positive expression for PLA2R. As far as we know, this is the first report of a case of primary MN in a patient with CD, with severe chronic cardiomyopathy and heart failure.

Focal and Segmental Glomerulosclerosis and Membranous Nephropathy overlapping in a patient with Nephrotic Syndrome: a case report / Glomeruloesclerose Segmentar e Focal e Nefropatia Membranosa sobrepostas em paciente com Síndrome Nefrótica: relato de caso

Abstract Introduction: Some cases of membranous nephropathy (MGN) present focal segmental glomerulosclerosis (FSGS) typically associated with disease progression. However, we report a case of a patient who seemed to have MGN and FSGS, both primary. Case presentation: A 17-year-old female, Caucasian, presenting lower extremity edema associated with episodes of foamy urine and high blood pressure, had physical and laboratorial exams indicating nephrotic syndrome. A renal biopsy was performed and focal and segmental glomerulosclerosis were observed under light microscopy in some glomeruli presented as tip lesion, and in others it was accompanied by podocyte hypertrophy and podocyte detachment in urinary space, compatible with podocytopathy FSGS. Besides, there were thickened capillary loops with basement membrane irregularities due to "spikes" compatible with MGN stage II. Immunofluorescence showed finely granular IgG, IgG4, and PLA2R deposits in capillary loops and, in electron microscopy, subepithelial deposits and foot process effacement. These morphological findings are compatible with FSGS and MGN stage II. Conclusions: In the present case, clinical and morphological characteristics showed a possible overlap of primary FSGS and MGN as focal and segmental glomerulosclerosis does not seem to be related with MGN progression but with the podocytopathy FSGS.

Resumo Introdução: Alguns casos de nefropatia membranosa (NM) apresentam glomeruloesclerose segmentar e focal (GESF) tipicamente associada a progressão da doença. Contudo, relatamos o caso de uma paciente que parece ter NM e GESF, ambas primárias. Apresentação do caso: Uma jovem branca de 17 anos de idade com edema de membros inferiores associado a episódios de urina espumosa e hipertensão apresentou-se com achados físicos e laboratoriais sugestivos de síndrome nefrótica. Foi realizada biópsia renal. GESF foi observada por microscopia de luz em alguns glomérulos que apresentavam lesões de ponta, enquanto em outros o achado era acompanhado por hipertrofia podocitária e descolamento de podócitos no espaço urinário, compatíveis com podocitopatia GESF. Além disso, as alças capilares estavam espessadas com irregularidades na membrana basal devido a "espículas" compatíveis com NM estágio II. Imunofluorescência revelou depósitos finamente granulares de IgG, IgG4 e PLA2R nas alças capilares. Microscopia eletrônica exibiu depósitos subepiteliais e apagamento de pedicelos. Tais achados morfológicos são compatíveis com GESF e NM estágio II. Conclusões: No presente caso, as características clínicas e morfológicas revelaram uma possível sobreposição de GESF primária e NM, uma vez que a glomeruloesclerose segmentar e focal não parece estar relacionada com a progressão da NM, mas com a podocitopatia GESF.

A rare case of PLA2R- and THSD7A-positive idiopathic membranous nephropathy / Positividade tecidual dupla para PLA2R e THSD7A em nefropatia membranosa idiopática: raro relato de caso

ABSTRACT Idiopathic membranous nephropathy (IMN) is a frequent cause of nephrotic syndrome in adults. In terms of etiology, the condition may be categorized as primary/idiopathic or secondary. Literature on the pathophysiology of IMN has indicated the presence of autoantibodies (PLA2R and THSD7A) directed against podocyte antigens. The detection of antibodies against a domain favors IMN. The presence of autoantibodies against one of the domains would in theory exclude the possibility of there being autoantibodies against the other domain. However, cases of patients with PLA2R- and THSD7A-positive disease have been recently reported, showing that antibodies against two targets may be concomitantly produced via yet unknown pathophysiological mechanisms. This study reports the case of a 46-year-old male patient with nephrotic-range proteinuria, hematuria, hypoalbuminemia, and hypercholesterolemia submitted to biopsy and histopathology examination (LM, IF, IHC, and EM) eventually diagnosed with PLA2R- and THSD7A-positive IMN associated with IgA nephropathy, stressing our experience with the use of IgG subclasses, PLA2R, and THSD7A in the workup for MN and the relevance of adopting a broad and adequate approach to elucidating and acquiring knowledge of the pathophysiology of IMN.

RESUMO A Nefropatia Membranosa Idiopática (NMi) é uma frequente causa de síndrome nefrótica em adultos e sua etiologia pode ser estratificada em primária/idiopática ou secundária. O conhecimento da fisiopatologia da NMi sugeriu a presença de autoanticorpos (PLA2R e a THSD7A) direcionados contra antígenos existentes nos podócitos. A detecção de anticorpos contra um domínio favorece NMi. A presença de autoanticorpos contra um desses domínios autoexcluiria a possibilidade de autoanticorpos contra o outro domínio; no entanto, recentemente foram descritos casos que apresentaram dupla positividade para PLA2R e THSD7A, comprovando que, por mecanismos fisiopatológicos ainda não conhecidos, raramente pode existir produção concomitante de anticorpos contra os dois alvos. O presente estudo tem por objetivo relatar o caso de um paciente de 46 anos de idade, do sexo masculino, que apresentou quadro de proteinúria nefrótica, hematúria, hipoalbuminemia e hipercolesterolemia submetido a biópsia e exame histopatológico (ML, IF, IHQ e ME), confirmando um caso raro de NMi com positividade dupla para os anticorpos anti-PLA2R e anti-THSD7A e associação à nefropatia por IgA, mostrando nossa experiência com a utilização de subclasses de IgG, PLA2R e THSD7A na rotina laboratorial para a investigação da GNM e enfatizando a importância de uma abordagem ampla para adequada elucidação e conhecimento dos mecanismos fisiopatológicos na NMi.

Recovery of renal function after bilateral renal vein thrombo sis episode as complication of membranous glomerulopa thy: case report / Recuperação da função renal após episódio de trombose de veia renal bilateral como complicação da glomerulopatia membranosa: relato de caso

ABSTRACT Renal vein thrombosis (RVT) is a complication often associated with nephrotic syndrome. It occurs due to a state of hypercoagulability common in the diseases that attend to this syndromic diagnosis. It should be suspected whenever there is nephrotic syndrome associated with sudden flank pain, hematuria and worsening of proteinuria. Bilateral RVT also presents with frequently oliguric renal dysfunction. This case reports a 33-year-old patient hospitalized for a nephrotic syndrome, with etiologic investigation suggestive of primary membranous glomerulopathy, which evolved with bilateral RVT associated with deterioration of renal function and need for renal replacement therapy. He promptly performed angiography with thrombectomy and thrombolysis, evolving with recovery of renal function in two weeks.

RESUMO A trombose de veia renal (TVR) é uma complicação muitas vezes associada à síndrome nefrótica. Ocorre devido a um estado de hipercoagulabilidade comum nas enfermidades que cursam com esse diagnóstico sindrômico. Deve ser suspeitada sempre que houver síndrome nefrótica associada à dor súbita em flanco, hematúria e piora da proteinúria. TVR bilateral cursa, ainda, com disfunção renal frequentemente oligúrica. Esse caso reporta um paciente de 33 anos internado por um quadro de síndrome nefrótica, com investigação etiológica sugestiva de glomerulopatia membranosa primária, que evoluiu com TVR bilateral associada à deterioração da função renal e necessidade de terapia substitutiva renal. Realizou, prontamente, angiografia com trombectomia e trombólise, evoluindo com recuperação da função renal em duas semanas.

Triggers, bullets and targets, puzzle of membranous nephropathy.

INTRODUCTION: Idiopathic Membranous Nephropathy (MN) is a common cause of adult nephrotic syndrome. Recently, M-type phospholipase A2 receptor (PLA2-R) has been discovered as the main podocyte antigen in the pathogenesis of idiopathic MN. MATERIALS AND METHODS: In this mini review, the author searched English-language MEDLINE for the terms "membranous nephropathy", "rituximab", and "phospholipase A2 receptor" up to October 2011. RESULTS: In support of its earlier discovery, reports from China and Europe confirmed the major pathogenic role of non-complement fixing IgG4 antibody against PLA2-R in the pathogenesis of idiopathic MN. Antibodies against aldose reductase (AR) and manganese superoxide dismutase (SOD2 ), and sub-epithelial deposition of cationic bovine serum albumin (BSA) are also reported in rare occasions. It seems that Rituximab is a good therapeutic choice for those patients who need immunosuppressive therapy. CONCLUSIONS: Great discoveries in the diagnosis and treatment of idiopathic MN have been performed but pathogenic mechanism and triggers for anti-PLA2-R production are still unknown.

Complement System and C4d expression in cases of Membranous nephropathy / Sistema complemento e expressão de C4d em casos de Glomerulopatia Membranosa

Abstract Introduction: Membranous nephropathy (MN) is one of the major causes of nephrotic syndrome. The complement system plays a key role in the pathophysiology of MN. Objectives: To identify the complement pathway possibly activated in MN cases and correlate the presence of C4d with more severe clinical and histological markers. Methods: Sixty nine cases from renal biopsy with membranous nephropathy were investigated. The presence of C1q was analyzed by direct immunofluorescence; and expression of C4d by immunohistochemistry. Clinical and epidemiological data were obtained upon biopsy request. Results: The presence of focal segmental glomerulosclerosis, global glomerulosclerosis, vascular lesions and tubulointerstitial fibrosis were collected by anatomopathological report. C4d(+) was found in 58 (84%), and C1q(+) was found in 12 (17%) of the cases. Twelve patients had C4d(+)/C1q(+), 46 had C4d(+)/C1q(-), and 11 patients had C4d(-)/C1q(-), probably indicating the activation of the classical, lectin and alternative pathways, respectively. Conclusion: C4d was associated with increased interstitial fibrosis, but not with clinical markers of poor prognosis. Through the deposition of C4d and C1q we demonstrated that all complement pathways may be involved in MN, highlighting the lectin pathway. The presence of C4d has been associated with severe tubulointerstitial lesions, but not with clinical markers, or can be taken as a universal marker of all cases of MN.

Resumo Introdução: A Glomerulopatia membranosa (GM) é uma das principais causas da síndrome nefrótica. O sistema do complemento desempenha um papel chave na fisiopatologia do GM. Objetivos: Identificar a via do complemento possivelmente ativada nos casos de GM e correlacionar a presença de C4d com marcadores clínicos e histológicos mais graves. Métodos: Foram investigados 69 casos de biópsia renal com GM. A presença de C1q foi analisada por imunofluorescência direta e a expressão de C4d por imunohistoquímica. Dados clínicos e epidemiológicos foram obtidos mediante solicitação de biópsia renal. Resultados: A presença de glomerulosclerose segmentar focal, glomeruloesclerose global, lesões vasculares e fibrose tubulointersticial foi coletada por relato anatomopatológico. C4d (+) foi encontrado em 58 (84%), e C1q (+) foi encontrado em 12 (17%) casos. Doze pacientes tinham C4d (+)/C1q (+), 46 tinham C4d (+)/C1q (-) e 11 pacientes tinham C4d (-)/C1q (-), indicando provavelmente a ativação da via clássica, da lectina e da alternativa, respectivamente. Conclusão: O C4d foi associado ao aumento da fibrose intersticial, mas não com marcador clínico de mau prognóstico. Através da deposição de C4d e C1q, demonstrou-se que todas as vias do complemento podem estar envolvidas em GM, destacando a via da lectina. A presença de C4d tem sido associada a lesões tubulointersticiais graves, mas não com marcadores clínicos, ou pode ser tomada como um marcador universal de todos os casos de GM.

Glomerulopatia membranosa: novos conhecimentos na fisiopatologia e possibilidades terapeuticas / Membranous glomerulonephritis: new insights in pathophysiology and therapeutic approach

Avanços dos conhecimentos moleculares na última década têm permitido a identificação de proteínas podocitárias que atuariam como alvos antigênicos na glomerulonefrite membranosa (GNM). Estudos envolvendo anticorpos contra estruturas podocitárias tem promovido o conceito autoimune da forma idiopática desta glomerulopatia. Neste contexto, o receptor de fosfolipase A2 do tipo M (PLA2R) tem merecido destaque como o primeiro e mais importante autoantígeno descrito na GNM idiopática humana. A presença do anticorpo anti-PLA2R tem sido destacada entre 70% e 89% de portadores da GNM idiopática, diferenciando das formas secundárias. Diversos estudos têm sugerido a detecção do anti-PLA2R como diagnóstico e apontado a correlação de seus níveis circulantes com a atividade clínica e resposta terapêutica. Entretanto, a coexistência de outros autoanticorpos sugere uma complexa via patogênica envolvendo diferentes antígenos podocitários. Estudos adicionais são necessários para esclarecer o tempo de aparecimento e o papel de cada anticorpo antipodócito no diagnóstico e progressão da GNM.

During the last decade, several major breakthroughs have led to the identification of human podocyte membrane antigens. Experimental involving antipodocyte antibodies in human membranous nephropathy (MN) have opened a new line of thinking about this disease, relating as an autoimmune kidney disease. In this setting, the M-type phospholipase A2 receptor (PLA2R) was identified as the first major antigen target in human primary MN. Studies have demonstrated anti-PLA2R antibodies against PLA2R ranging from 70 to 89% in patients with MN, but not in those with secondary MN. It has been suggested that the serum level of anti-PLA2R could be used for the diagnosis of idiopathic MN and for the monitoring of response to treatment. However, the coexistence of autoantibodies suggests a complex pathogenic pathway that involves different podocyte targets. New experimental models are needed to elucidate the appearance time and the role of each anti-podocyte antibody in MN development and progression.