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Anti-brush border antibody (ABBA) disease, also called anti–low-density lipoprotein receptor-related protein 2 (anti-LRP2) nephropathy, occurs due to the formation of antibodies against brush border antigens of the renal proximal convoluted tubule. We report a case of ABBA disease in a male farmer in his 30s who presented with 2 years of polyuria, dysuria, nocturia, and urinary urgency. He described a history of long-term occupational exposure to pesticides and silica, evolving into possible pneumoconiosis, and prior pulmonary tuberculosis. At presentation, he had reduced kidney function (serum creatinine 3.6 mg/dL) with hyponatremia, hypokalemia, hypophosphatemia, a normal anion gap, metabolic acidosis, and respiratory acidosis, and 2.2 g/day of urine proteinuria. The kidney biopsy was consistent with ABBA, showing amorphous immune-deposits in the tubular basement membrane and strong positivity on indirect immunofluorescence in the brush border of the proximal tubules. The trigger for production of ABBA is still unknown, but it may be associated with chronic conditions such as pulmonary tuberculosis and occupational exposures such as silica and pesticides, as seen in the patient in this report. Most cases do not respond to immunosuppression, and the prognosis is poor.

Liver test abnormalities are frequently observed in patients with coronavirus disease 2019 (COVID‐19) and are associated with worse prognosis. However, information is limited about pathological changes in the liver in this infection, so the mechanism of liver injury is unclear. Here we describe liver histopathology and clinical correlates of 27 patients who died of COVID‐19 in Manaus, Brazil. There was a high prevalence of liver injury (elevated alanine aminotransferase and aspartate aminotransferase in 44% and 48% of patients, respectively) in these patients. Histological analysis showed sinusoidal congestion and ischemic necrosis in more than 85% of the cases, but these appeared to be secondary to systemic rather than intrahepatic thrombotic events, as only 14% and 22% of samples were positive for CD61 (marker of platelet activation) and C4d (activated complement factor), respectively. Furthermore, the extent of these vascular findings did not correlate with the extent of transaminase elevations. Steatosis was present in 63% of patients, and portal inflammation was present in 52%. In most cases, hepatocytes expressed angiotensin‐converting enzyme 2 (ACE2), which is responsible for binding and entry of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), even though this ectoenzyme was minimally expressed on hepatocytes in normal controls. However, SARS‐CoV‐2 staining was not observed. Most hepatocytes also expressed inositol 1,4,5‐triphosphate receptor 3 (ITPR3), a calcium channel that becomes expressed in acute liver injury. Conclusion: The hepatocellular injury that commonly occurs in patients with severe COVID‐19 is not due to the vascular events that contribute to pulmonary or cardiac damage. However, new expression of ACE2 and ITPR3 with concomitant inflammation and steatosis suggests that liver injury may result from inflammation, metabolic abnormalities, and perhaps direct viral injury., New expression of ACE2 and ITPR3 in hepatocytes with concomitant inflammation and steatosis suggests that the frequently observed liver injury in patients with COVID‐19 may result from inflammation, metabolic abnormalities, and perhaps direct viral entry.

Objective: To evaluate the evolution of histological findings of patients with biliary atresia (BA), emphasizing the progression of fibrosis by comparing the diagnostic liver biopsy to the surgical liver biopsy, performed during Kasai portoenterostomy. Methods: Retrospective study with 51 patients with BA submitted to portoenterostomy, and both diagnostic (DLB) and surgical liver biopsies (SLB). The samples were blindly reviewed by two pathologists. Results: Median age at DLB and at SLB was 69 and 77 days, respectively. The median time between biopsies was eight days. Cirrhosis was more frequent in SLB than in DLB, both according to the Metavir score (p = 0.006) and the Ishak score (p = 0.016). The Metavir score increased one or more points in 29/51 (56.9%), with evidence of progression to liver cirrhosis in 11/29 (37.9%) of those who had progression of fibrosis. Median age at surgery of those who had a progression of fibrosis was 77 days, while in those 11 who progressed to cirrhosis, this median was 92 days. Cirrhosis was seen in 12/51 (23.5%) SLB patients. The clinical variable age at surgery had a statistically significant difference regarding the presence or absence of cirrhosis in SLB (p = 0.024). Cirrhosis was not related to survival with native liver or biliary drainage. Conclusion: Most infants with BA have liver fibrosis at diagnosis and it progresses rapidly. The presence of cirrhosis is correlated with the age at surgery, which suggests the importance of this clinical variable in the evolution of fibrosis. RESUMEN Objetivo: Analizar la evolución de los hallazgos histológicos de pacientes con atresia de vías biliares (AVB), resaltando la progresión de la fibrosis y comparando la biopsia hepática diagnóstica (BHD) con la biopsia hepática quirúrgica (BHQ) mediante la hepatoportoenterostomía de Kasai. Método: Estudio retrospectivo con 51 pacientes con AB sometidos a hepatoportoenterostomía, BHD y BHQ. Resultados: La edad mediana para BHD y BHQ fue 69 días y 77 días, respectivamente. El tiempo mediano entre las biopsias fue ocho días. La cirrosis fue más frecuente en la BHQ de lo que en la BHD, tanto de acuerdo con el escore de Metavir (p = 0,006) como con el escore de Ishak (p = 0,016). El escore de Metavir aumentó un punto o más en 29/51 (59,9%) pacientes, con evidencias de progresión hacia cirrosis hepática en 11/29 (37,9%), en los pacientes con progresión de la fibrosis. La edad mediana para cirugía de los que tuvieron progresión de la fibrosis fue 77 días; en los 11 que evolucionaron hacia cirrosis, esa mediana fue 92 días. La variable clínica de edad en el momento de la cirugía presentó diferencia estadísticamente significante con respecto a la presencia o ausencia de cirrosis (p = 0,024). La cirrosis no fue asociada a la sobrevida con hígado nativo o drenaje biliar. Conclusión: La mayor parte de los niños con AVB tiene fibrosis hepática en el momento del diagnóstico, y la enfermedad avanza rápidamente. La presencia de cirrosis está relacionada con la edad al momento de la cirugía, lo que sugiere la importancia de esa variable clínica en la evolución de la fibrosis. RESUMO Objetivo: Avaliar a evolução dos achados histológicos de pacientes com atresia biliar (AB), enfatizando a progressão da fibrose e comparando a biópsia hepática diagnóstica (BHD) com a biópsia hepática cirúrgica (BHC), realizada durante a portoenterostomia de Kasai. Método: Estudo retrospectivo com 51 pacientes portadores de AB submetidos a portoenterostomia, BHD e BHC. Resultados: A idade mediana para BHD e BHC foi de 69 e 77 dias de idade, respectivamente. O tempo mediano entre as biópsias foi de oito dias. A cirrose foi mais frequente na BHC do que na BHD, tanto de acordo com o escore de Metavir (p = 0,006) quanto com o escore de Ishak (p = 0,016). O escore de Metavir aumentou um ou mais pontos em 29/51 (56,9%) pacientes, com evidências de progressão para cirrose hepática em 11/29 (37,9%), naqueles com progressão da fibrose. A idade mediana para cirurgia dos que tiveram progressão da fibrose foi de 77 dias; nos 11 que evoluíram para cirrose, essa mediana foi de 92 dias. A variável clínica da idade no momento da cirurgia apresentou diferença estatisticamente significativa em relação à presença ou à ausência de cirrose (p = 0,024). A cirrose não foi associada à sobrevida com fígado nativo ou drenagem biliar. Conclusão: A maioria das crianças com AB tem fibrose hepática no momento do diagnóstico, e a doença progride rapidamente. A presença de cirrose está correlacionada com a idade à cirurgia, o que sugere a importância dessa variável clínica na evolução da fibrose.

A 17-year-old male presented thrombotic microangiopathy (TMA) at 6 months of age with arterial hypertension, anemia, thrombocytopenia and kidney injury improving with plasma infusions. Fourteen years later, he was diagnosed with severe arterial hypertension, increase in serum creatinine and chronic TMA on kidney biopsy. Eculizumab was started and after 18 months of treatment, he persisted with hypertension, decline in renal function and proteinuria. Genetic analysis demonstrated mutation in diacylglycerol kinase epsilon (DGKe). Complement blockade was stopped. This case of late diagnosis of DGKe nephropathy highlights the importance of genetic testing in patients presenting TMA during the first year of life.

Background Lipoprotein glomerulopathy (LPG) is a rare autosomal dominant disease caused by mutations in APOE, the gene which encodes apolipoprotein E. LPG mainly affects Asian individuals, however occasional cases have also been described in Americans and Europeans. Herein we report two unrelated Brazilian patients with LPG in whom genetic analyses revealed the APOE-Osaka/Kurashiki variant. Case presentation - case 1 A 29-year-old Caucasian male sought medical attention with complaints of face swelling and foamy urine for the last 3 months. He denied a family history of kidney disease, consanguinity, or Asian ancestry. His tests showed proteinuria of 12.5 g/24 h, hematuria, serum creatinine 0.94 mg/dL, albumin 2.3 g/dl, total cholesterol 284 mg/dL, LDL 200 mg/dL, triglycerides 175 mg/dL, and negative screening for secondary causes of glomerulopathy. A kidney biopsy revealed intraluminal, laminated deposits of hyaline material in glomerular capillaries consistent with lipoprotein thrombi. These findings were confirmed by electron microscopy, establishing the diagnosis of LPG. His apolipoprotein E serum level was 72 mg/dL and genetic analysis revealed the APOE pathogenic variant c.527G > C, p.Arg176Pro in heterozygosis, known as the Osaka/Kurashiki mutation and positioned nearby the LDL receptor binding site. Case 2 A 34-year-old Caucasian man sought medical assessment for renal dysfunction and hypertension. He reported intermittent episodes of lower-limb edema for 3 years and a family history of kidney disease, but denied Asian ancestry. Laboratorial tests showed BUN 99 mg/dL, creatinine 10.7 mg/dL, total cholesterol 155 mg/dL, LDL 79 mg/dL, triglycerides 277 mg/dL, albumin 3.1 g/dL, proteinuria 2.7 g/24 h, and negative screening for secondary causes of glomerulopathy. His kidney biopsy was consistent with advanced chronic nephropathy secondary to LPG. A genetic analysis also revealed the Osaka/Kurashiki variant. He was transplanted a year ago, displaying no signs of disease relapse. Conclusion We report two unrelated cases of Brazilian patients with a diagnosis of lipoprotein glomerulopathy whose genetic assessment identified the APOE-Osaka/Kurashiki pathogenic variant, previously only described in eastern Asians. While this is the second report of LPG in Latin America, the identification of two unrelated cases by our medical team raises the possibility that LPG may be less rare in this part of the world than currently thought, and should definitely be considered when nephrotic syndrome is associated with suggestive kidney biopsy findings.

Kidney involvement appears to be frequent in coronavirus disease 2019 (COVID-19). Despite this, information concerning renal involvement in COVID-19 is still scarce. Several mechanisms appear to be involved in the complex relationship between the virus and the kidney. Also, different morphological patterns have been described in the kidneys of patients with COVID-19. For some authors, however, this association may be just a coincidence. To investigate this issue, we propose assessing renal morphology associated with COVID-19 at the renal pathology reference center of federal university hospitals in Brazil. Data will come from a consortium involving 17 federal university hospitals belonging to Empresa Brasileira de Serviços Hospitalares (EBSERH) network, as well as some state hospitals and an autopsy center. All biopsies will be sent to the referral center for renal pathology of the EBSERH network. The data will include patients who had coronavirus disease, both alive and deceased, with or without pre-existing kidney disease. Kidney biopsies will be analyzed by light, fluorescence, and electron microscopy. Furthermore, immunohistochemical (IHC) staining for various inflammatory cells (i.e., cells expressing CD3, CD20, CD4, CD8, CD138, CD68, and CD57) as well as angiotensin-converting enzyme 2 (ACE2) will be performed on paraffinized tissue sections. In addition to ultrastructural assays, in situ hybridization (ISH), IHC and reverse transcription-polymerase chain reaction (RT-PCR) will be used to detect Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) in renal tissue. For the patients diagnosed with Collapsing Glomerulopathy, peripheral blood will be collected for apolipoprotein L-1 (APOL1) genotyping. For patients with thrombotic microangiopathy, thrombospondin type 1 motif, member 13 (ADAMTS13), antiphospholipid, and complement panel will be performed. The setting of this study is Brazil, which is second behind the United States in highest confirmed cases and deaths. With this complete approach, we hope to help define the spectrum and impact, whether immediate or long-term, of kidney injury caused by SARS-CoV-2.

Fibrillary Glomerulonephritis (FGN) is a rare glomerulopathy, corresponding to less than 1% of all renal biopsies performed. The pathogenesis mechanisms of FGN are still not completely understood and most cases are considered idiopathic. The clinical presentation is characterized by proteinuria, hematuria, arterial hypertension and renal failure. The evaluation of FGN is a diagnostic challenge in the practice of the pathologist, because there are no morphological characteristics with highly specific or pathognomonic lesion. The use of a sensitive and specific biomarker can make an important contribution to renal pathology and the differential diagnosis of diseases with fibrillar deposits. In this contexto, DNAJB9 can be investigated by immunohistochemical technique and is useful for the diagnostic definition of FGN.

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.

BACKGROUND: Biliary atresia represents the most common surgically treatable cause of cholestasis in newborns. If not corrected, secondary biliary cirrhosis invariably results. OBJECTIVE: To evaluate, through multivariate analysis, the prognostic factors associated with the presence of biliary flow and survival with the native liver following Kasai portoenterostomy. METHODS: The study analyzed data from 117 biliary atresia patients who underwent portoenterostomy and had suitable histological material for evaluation. A logistic regression model was used to assess the presence of biliary flow. Survival was investigated through Kaplan-Meier curves and Cox-adjusted models. RESULTS: One third of patients achieved biliary flow and the median age at surgery was 81 days. Age at surgery, albumin, postoperative complications, biliary atresia structural malformation (BASM), liver architecture, larger duct diameter at porta hepatis, and cirrhosis (Ishak score) were the initial variables for the multivariate analysis. Age at surgery >90 days was the only variable associated with the absence of biliary drainage. Survival analysis revealed that the absence of biliary flow (P90 days (P=0.035), and the presence of BASM (P90 days was associated with absence of biliary flow. The presence of biliary drainage and the absence of structural malformations are cornerstone features for higher survival rates with the native liver. RESUMO CONTEXTO: A atresia biliar representa a principal causa de colestase tratada cirurgicamente durante o período neonatal. Se a criança não for operada, ela evolui invariavelmente para cirrose biliar secundária. OBJETIVO: Avaliar, através de análise multivariada, os fatores prognósticos associados à presença de fluxo biliar e à sobrevida com fígado nativo após a realização da portoenterostomia de Kasai. MÉTODOS: O estudo analisou 117 pacientes com atresia biliar submetidos à portoenterostomia e com material histológico adequado para avaliação. O modelo de regressão logística foi utilizado para avaliar a presença de fluxo biliar. Sobrevida foi estudada através das curvas Kaplan-Meier e ajuste do modelo de Cox. RESULTADOS: Um terço dos pacientes obteve fluxo biliar e a mediana de idade à cirurgia foi de 81 dias. Idade à cirurgia, albumina, complicação pós-operatória, BASM (do inglês, biliary atresia structural malformation), arquitetura hepática, diâmetro do maior canalículo no porta hepatis e cirrose, segundo o escore de Ishak, foram as variáveis iniciais da análise multivariada. Idade à cirurgia maior que 90 dias de vida foi a única variável associada à ausência de drenagem biliar. A análise de sobrevida mostrou que as variáveis: ausência de fluxo biliar (P

Background The identification of low-level antibodies by single-antigen bead methodology has brought advancements to risk evaluation of kidney transplant recipients. However, the use of mean fluorescence intensity (MFI) to quantify antibodies and to guide therapy is not enough. Notably, immunoglobulin G (IgG) subclass switching is hypothesized to follow a programmed sequence after an emergency signal from the germinal center. In transplantation this process is not clear yet. In the present study, we sequentially evaluate anti-HLA donor specific antibody (DSA) subclasses, their profile changes, and C1q-binding ability and the influence of those characteristics on antibody mediated rejection (AMR) occurrence and allograft function. Methods A total of 30 DSA-positive patients were tested for IgG subclass content and C1q-binding in sequential serum samples. Results Twenty-one patients were DSA-positive before transplant; patients sensitized only by transfusion or pregnancies had IgG1 and/or IgG3, and patients sensitized by both transfusion and pregnancies or previous transplant showed a broader range of IgG subclasses. C1q binding was detected in high MFI made up of IgG1 or multiple IgG subclasses. Only 4 patients were positive for C1q posttransplantation and 3 of these showed an increase in MFI, changes in subclasses patterns, AMR, and allograft dysfunction. Conclusions Posttransplant evaluation of DSA subclasses and the ability to bind C1q may be informative for both AMR occurrence and allograft dysfunction. Monitoring these events may help to better define risk and interventional time points.

INTRODUCTION: Preeclampsia is responsible for high maternal mortality in Brazil and worldwide. Its etiology has not been fully elucidated. Placental changes in preeclampsia include: infarcts, increase in syncytial knots, villous hypotrophy, thickening of trophoblastic basement membrane and fibrin deposition. OBJECTIVE: To analyze quantitatively images of perivillous fibrinoid material present in placentas from pregnancies with and without preeclampsia. MATERIAL AND METHODS: A case-control study was carried out at the Anatomical Pathological Service of Professor Alberto Antunes University Hospital. It was performed the histomorphometric analysis of 840 images comprising 14 placenta samples from pregnancies with preeclampsia (cases) and 14 placenta samples from pregnancies without preeclampsia (controls). RESULTS: In the preeclampsia group the mean area of fibrinoid material was 168.46 pixels and in the group without preeclampsia it was 89.63 pixels. The nuclei total area was smaller in preeclampsia (89.51 pixels) in comparison with the control group (113.34 pixels). CONCLUSION: In placentas from preeclampsia pregnancies the fibrinoid material area is larger (1.8x) compared to normal pregnancies. Nuclei and cytoplasm areas were larger in the control group. There was no statistical difference regarding the stromal area. There was also a reduction in villous space in preeclampsia, which is consistent with villous hypotrophy.

O aneurisma da artéria esplênica é uma entidade clínica rara, embora seja o mais frequente entre os aneurismas viscerais, sendo encontrado em 0,8% da população. Apresenta-se mais frequentemente em mulheres, na proporção de 4:1, e raramente provoca sintomas ou sinais clínicos. Desenvolve-se de forma assintomática e, na maioria dos casos, é diagnosticado por meio de exames indicados para elucidar queixas clínicas decorrentes de outras doenças ou quando apresenta complicações por vezes fatais, como a rotura. A possibilidade de rotura dos aneurismas de artéria esplênica com diâmetro inferior a 2 cm é baixa; entretanto, os que apresentam diâmetro igual ou maior que 3 cm são usualmente encaminhados para tratamento cirúrgico, devido ao alto risco de rotura. O tratamento eletivo é indicado nos casos não complicados, sendo a embolização com molas um método interessante por evitar o tratamento cirúrgico convencional.