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.

Nefropatía membranosa secundaria a exposición laboral con mercurio metálico

Las nefropatías tóxicas secundarias a la exposición ocupacional a metales han sido ampliamente estudiadas. La nefropatía membranosa por mercurio es poco frecuente.La intoxicación ocupacional con mercurio sí es frecuente, siendo las principales formas de presentación las manifestaciones clínicas neurológicas. La afectación renal secundaria a la exposición crónica a mercurio metálico puede desarrollar enfermedad glomerular por depósito de inmunocomplejos. La glomerulopatía membranosa y a cambios mínimos son las más frecuentemente comunicadas.Se presenta el caso de un paciente con exposición ocupacional a mercurio metálico, con síndrome nefrótico y biopsia renal con glomerulopatía membranosa que presentó respuesta favorable luego del tratamiento quelante e inmunosupresor.

Toxic nephrophaties secondary to occupational exposure to metals have been widely studied, including membranous nephropathy by mercury, which is rare. Occupational poisoning by mercury is frequent, neurological symptoms are the main form of clinical presentation. Secondary renal involvement in chronic exposure to metallic mercury can cause glomerular disease by deposit of immune-complexes. Membranous glomerulopathy and minimal change disease are the most frequently reported forms. Here we describe the case of a patient with occupational exposure to metallic mercury, where nephrotic syndrome due to membranous glomerulonephritis responded favorably to both chelation and immunosuppressive therapy.

Remisión completa de síndrome nefrótico asociado a carcinoma cervicouterino luego de tratamiento del tumor: Comunicación de 2 casos / Complete remission of nephrotic syndrome associated with carcinoma of the cervix after treatment of the tumor: Report of two cases

Nephrotic syndrome secondary to paraneoplastic glomerulopathies is exceptional. We are aware of only three cases reported of cervical carcinomas associated with nephrotic syndrome. Two women, aged 40 and 79 years, presented with nephrotic syndrome. The first had a membranous nephropathy and the second was not biopsied. The first women had a metrorrhagia after 8 months of unsuccessful therapy with corticosteroids and immunosuppressive drugs. An advanced cervical carcinoma with lymph node metastases was found. In the second patient, a cervical carcinoma and hematometra was discovered two months after diagnosis ofa nephrotic syndrome. The syndrome subsided completely, nine months after radiotherapy and chemotherapy in the first patient and 10 months after hysterectomy in the second patient.

Hepatitis B virus-associated nephropathy: an international data analysis

Hepatitis B virus [HBV]-associated nephropathy is one of the manifestations of HBV infection. However, since it is not common, the patient populations of reports are usually limited. In order to have a more perfect understanding of the disease, we conducted this analysis of data published in articles of the English literature on HBV-associated nephropathy. We conducted a comprehensive search for the available publications on HBV-associated nephropathy through the PubMed. The patients were defined as pediatric when they were 18 years old or younger. The definition criteria for complete remission were in part different between studies, but a generalized definition was taken as a significant decrease in the proteinuria to levels around normal with no relapse episodes in 1 year after remission. Overall, 119 patients from 10 reports were included into this analysis. All of the patients using lamivudine experienced remissions compared to those receiving other treatment modalities [P=.001], of whom 72.7% [16 of 22] had complete remission [P=.08]. None of lamivudine recipients lost their kidneys [P=.04]. Pediatric patients were more frequently positive for hepatitis B envelop antigen [P=.001]. Immunoglobulin A nephropathy was more frequent among adult patients [P=.01], and membranous nephropathy in children [P=.01]. Children represented significantly higher levels for aspartate aminotransferase [P=.004] and alanine aminotransferase [P=.002]. Lamivudine therapy can effectively be used to stop progression of HBV-associated nephropathy. Pediatric patients represent different serological and laboratorial test results compared to their adult counterparts. Future studies with larger patient population are needed to confirm our findings

La nefropatia membranosa del adulto / Membranous kidney diseases in adults

La glomerulopatía membranosa es el fenotipo histológico más frecuentemente asociado al síndrome nefrótico en el adulto y si bien globalmente la sobrevida renal a 10 años es del 70%, su evolución en el paciente individual depende de la función renal en el momento del diagnóstico, la naturaleza y extensión del daño glomerular y túbulo-intersticial, la presencia de hipertensión y la magnitud de la proteinuria. Si bien sehan desarrollado modelos matemáticos para predecir su historia natural, la capacidad para predecirla es limitaday excepto en mujeres jóvenes con función renal normal, una biopsia renal con poca esclerosis, normotensióny proteinuria no nefrótica, en general el tratamiento medicamentoso se ve apoyado por los resultados obtenidosen estudios controlados y aleatorizados. El uso de esteroides con clorambucil o ciclofosfamida, o laciclosporina A son los recursos terapéuticos de valor mejor establecido para inducir remisiones duraderas de laproteinuria y preservación de la función renal, si bien el micofenolato mofetil y tal vez el rituximab se incorporen al uso habitual en especial en casos resistentes a las dos alternativas anteriores.

Membranous Nephropathy after Allogeneic Hematopoietic Stem Cell Transplantation in a Patient with Aplastic Anemia: A Case Report

Nephrotic syndrome has been described as one of the clinical forms of chronic graft-versus-host disease (cGVHD), but a limited number of cases have been described. We experienced a young female patient with nephrotic syndrome developed 22 months after allogeneic hematopoietic stem cell transplantation (HSCT) for severe aplastic anemia. She had been well after successful management for gut-limited cGVHD until she developed a clinical nephrotic syndrome with hypoalbuminemia of 2.0 g/dL and 24-hr urine protein of 6.88 g/dL. On physical examination and laboratory findings, there was no other evidence of cGVHD. Clinical and renal biopsy findings were consistent with cGVHD-related membranous nephropathy, and immunosuppressive agents with cyclosporine and prednisone were prescribed. After 3 month of treatment, the proteinuria decreased to normal range; and the patient from nephrotic syndrome nearly recovered. We recommend cGVHD-related glomerulonephritis should be considered in all patients with hypoalbuminemia following allogeneic HSCT, even if there is no other evidence of clinical GVHD.

Membranous glomerulonephritis and the nephrotic syndrome in a patient with Landry-Guillain-Barré-Strohl syndrome

Membranous glomerulonephritis and the nephrotic syndrome concurrent with the Miller-Fisher variant of the Landry-Guillain-Barré-Strohl syndrome (LGBS), acute post-infective polyneuritis, is reported in a 49-year-old man. The onset of heavy proteinuria coincided with the development of the neurological disturbance. While immunosuppressive therapy appeared to hasten improvemente in the neurological disease, no such improvemente occurred in the glomerulopathy