Yellow fever and orthotopic liver transplantation: new insights from the autopsy room for an old but re-emerging disease.

AIMS: The clinical spectrum of yellow fever (YF) ranges from asymptomatic to fulminant hepatitis. During the sylvatic YF epidemic in the metropolitan area of São Paulo, Brazil in 2018, seven orthotopic liver transplantations (OLTs) were performed in our institution to treat fulminant YF hepatitis. Three patients recovered, while four patients died following OLT. The autopsy findings of all these cases are presented herein as the first description of YF in transplanted patients. METHODS AND RESULTS: All patients were men, aged 16-40 years, without vaccination to YF virus (YFV). All organs were examined, with tissue sampling for histopathological analysis. Detection of YF virus antigens (YFV Ag) was performed with two primary antibodies (mouse polyclonal anti-YFV antibody directed to wild strain and a goat anti-YF virus antibody), and RT-PCR assays were utilised to detect YFV-RNA. All the cases depicted typical findings of YF hepatitis in the engrafted liver. The main extrahepatic findings were cerebral oedema, pulmonary haemorrhage, pneumonia, acute tubular necrosis and ischaemic/reperfusion pancreatitis. Of the four cases, the YVF Ag was detected in the heart in one case, liver and testis in three cases, and the kidney and spleen in all four cases. All four cases had YF virus RNA detected by RT-PCR in the liver and in other organs. CONCLUSIONS: Infection of the engrafted liver and other organs by YFV, possibly combined with major ischaemic systemic lesions, may have led to the death of four of the seven patients undergoing OLT.

Ultrastructure of vascular permeability in urticaria.

BACKGROUND: Few studies have addressed the ultrastructure of vascular permeability in urticaria. OBJECTIVES: To describe the types of endothelial cell organelles involved in vascular permeability in drug-induced acute urticaria (DIAU). METHODS: Seven patients with DIAU were enrolled in the study. Biopsies of urticarial lesions and apparently normal skin were performed. The 14 collected fragmentswere processed with immunogold electron microscopy using single stains for tryptase and factor XIIIa (FXIIIa) and double immunogold labeling for both tryptase and FXIIIa. RESULTS: Some sections demonstrated mast cells in the degranulation process, in both anaphylactic and piecemeal degranulation. After double immunogold staining, 10 nm (FXIIIa) and 15 nm (tryptase) gold particles wereboth present, covering the granules in the mast cells, indicating that both tryptase and FXIIIa were localized within the granules of these cells. Interestingly, we found strong evidence of the presence of caveolae and vesico-vacuolar organelles (VVOs) in the endothelial cells of the biopsies. In addition to these findings, we were able to demonstrate the presence of tryptase and FXIIIa in the endothelial celIs, in urticarial lesions and in apparently normal skin. CONCLUSIONS: VVOs are present in the endothelial cells of post-capillary venules in DIAU. This is the first report on the expression of FXIIIa and tryptase in the cytoplasm of endothelial cells in urticaria.

Immunoelectron microscopy study of superficial skin nerves in drug-induced acute urticaria.

BACKGROUND: Few studies have evaluated the ultrastructure of the superficial skin nerves in urticaria. OBJECTIVE: The objective of this study was to describe findings in superficial skin nerves in cases of drug-induced acute urticaria. METHODS: Seven patients with drug-induced acute urticaria were included in the study. Skin biopsies were obtained from the urticarial lesion and from the apparently normal skin. The 14 fragments collected were processed for immunogold electron microscopy using single stains for antitryptase and anti-FXIIIa antibodies, as well as double immunogold labeling for both. RESULTS: Some sections showed mast cells in the process of degranulation. Following double immunogold staining, 10 nm (FXIIIa) and 15 nm (Tryptase) gold particles were found together throughout the granules in mast cells, indicating that tryptase and FXIIIa are located inside each one of the granules of these cells. Interestingly, we found strong evidence of the presence of tryptase and factor XIIIa in the superficial skin nerves of these patients, both in cases of urticarial lesions (wheals) and in the apparently normal skin. CONCLUSIONS: Tryptase and FXIIIa are present in the superficial nerves of the skin in drug-induced acute urticaria. This is the first report of tryptase and FXIIIa expression in the superficial skin nerves of patients with urticaria. Tryptase may be participating in neural activation in these patients, while FXIIIa may be present in the nerves to guarantee the functional integrity of structures.

Immunoelectron microscopy study of superficial skin nerves in drug-induced acute urticaria / Estudo de microscopia imunoeletrônica dos nervos superficiais da pele na urticária aguda induzida por medicamentos

BACKGROUND: Few studies have evaluated the ultrastructure of the superficial skin nerves in urticaria. OBJECTIVE: The objective of this study was to describe findings in superficial skin nerves in cases of drug-induced acute urticaria. METHODS: Seven patients with drug-induced acute urticaria were included in the study. Skin biopsies were obtained from the urticarial lesion and from the apparently normal skin. The 14 fragments collected were processed for immunogold electron microscopy using single stains for antitryptase and anti-FXIIIa antibodies, as well as double immunogold labeling for both. RESULTS: Some sections showed mast cells in the process of degranulation. Following double immunogold staining, 10 nm (FXIIIa) and 15 nm (Tryptase) gold particles were found together throughout the granules in mast cells, indicating that tryptase and FXIIIa are located inside each one of the granules of these cells. Interestingly, we found strong evidence of the presence of tryptase and factor XIIIa in the superficial skin nerves of these patients, both in cases of urticarial lesions (wheals) and in the apparently normal skin. CONCLUSIONS: Tryptase and FXIIIa are present in the superficial nerves of the skin in drug-induced acute urticaria. This is the first report of tryptase and FXIIIa expression in the superficial skin nerves of patients with urticaria. Tryptase may be participating in neural activation in these patients, while FXIIIa may be present in the nerves to guarantee the functional integrity of structures.

FUNDAMENTOS: Poucos autores têm estudado a ultraestrutura dos nervos superficiais na urticária. OBJETIVO: Descrever os achados nos nervos cutâneos superficiais em casos de urticária aguda induzida por medicamentos. MÉTODOS: Sete pacientes com urticária aguda induzida por medicamentos foram incluídos no estudo. Foram obtidas biopsias da pele da lesão urticariforme e da pele aparentemente normal. Os 14 fragmentos coletados foram processados usando imunomarcação com ouro para anticorpos anti-triptase e anti-FXIIIa separadamente, além da dupla imunomarcação com ambos anticorpos. A seguir as amostras foram submetidas à análise por microscopia imunoeletrônica. RESULTADOS: Alguns cortes demonstraram mastócitos em processo de degranulação. Após a imunomarcação dupla, partículas de ouro de 10 nm (FXIIIa) e partículas de ouro de 15 nm (Triptase) apresentavam-se juntas em grânulos de mastócitos indicando que a triptase e o FXIIIa se localizam dentro de cada um dos grânulos dessas células. Curiosamente, foi encontrada uma forte evidência da presença da triptase e do fator XIIIa nos nervos superficiais dos pacientes avaliados, tanto em lesões urticadas, como na pele aparentemente normal. CONCLUSÕES: A triptase e o FXIIIa estão presentes nos nervos superficiais da pele na urticária aguda medicamentosa. Este é o primeiro relato da expressão de triptase e de FXIIIa nos nervos superficiais na urticária. A triptase poderia estar participando da ativação neural nos pacientes estudados. O FXIIIa poderia estar presente nos nervos, com a finalidade de manter a integridade funcional dessas estruturas.

Revisiting the liver in human yellow fever: virus-induced apoptosis in hepatocytes associated with TGF-beta, TNF-alpha and NK cells activity.

Flavivirus infection as dengue and yellow fever persists as a terrible menace to pandemics, due to Aedes prevalence in the Americas. Yellow fever is characterized by hepatocyte damage, with steatosis, apoptosis and necrosis, mainly in the midzonal region of the liver, but the injury mechanism has not been studied at the light of recent knowledge, such as the advances in cell death mechanisms, inflammatory response and cytokine cell expression tools. We studied 53 human liver paraffin embedded blocks from patients who died with yellow fever, all with histological demonstration of higher prevalence of apoptosis over necrosis and mild disproportionate inflammatory response. Viral antigens were found most frequently in hepatocytes from the midzonal area than other lobule areas, as detected by specific immunohistochemistry. Infiltrating cell subpopulations showed mainly CD4+ T lymphocytes, with small numbers of CD8+ cytotoxic lymphocytes, CD20+ B lymphocytes, NKT+ cells and S100+ dendritic cells in the sites of inflammation, as compared to normal and leptospirosis liver blocks. Some cells expressed TNF-alpha and IFN-gamma, but a much more intense proportion of TGF-beta expressing cells were found, suggesting both a Th1 and Th3 patterns of immune response in yellow fever. Most affected hepatocyte presented apoptosis markers that appear at the cell death main pathway in this infection. Viral antigens, which production could interfere in hepatocyte biology, could induce the activation of apoptosis cascade, but TGF-beta was also an apoptosis promoter. Our finding supports the key effect of the yellow fever virus in hepatocyte injury, resulting in prevalence of apoptosis over necrosis, aside from a TGF-beta action induced by the inflammatory response.

Imunomapeamento no diagnóstico das epidermólises bolhosas hereditárias distróficas / Immunomapping in the diagnosis of hereditary epidermolysis bullosa dystrophica

O objetivo deste estudo é mostrar as vantagens da técnica de imunomapeamento no diagnóstico das epidermólises bolhosas distróficas. Dos 37 doentes estudados realizou-se 28 exames anatomopatológicos, 23 exames de microscopia eletrônica de transmissão e 37 imunomapeamentos. Dos exames histopatológicos 3 foram compatíveis com epidermólise bolhosa simples (EBS) e 25 com os grupos das epidermólises bolhosas juncionais (EBJ) e das epidermólises bolhosas distróficas (EBD). Dos 19 exames de microscopia eletrônica de transmissão representativos, 2 foram compatíveis com EBS, 1 com EBJ e 16 com EBD. Nos imunomapeamentos 3 foram compatíveis com EBS, 3 com EBJ, 14 com EBD dominante (EBBD) e 17 com EBD recessiva (EBDR). O imunomapeamento pôde fazer a diferenciação dos dois grupos das EBD de forma mais fácil e de custo inferior ao da MET. Sabe-se que essa diferenciação pode ser feita pela MET, no entanto exige avaliação morfológica e quantificação das fibrilas de ancoragem, tornando esta técnica difícil, demorada e sujeita e erros por trabalhar com área restrita da zona da membrana basal

Estudo ao microscópico óptico e eletrônico de transmissäo na cicatrizaçäo de feridas produzidas pelo laser de CO2 no palato do rato / Light and transmission electron microscopic study of CO2 laser wound healing on palatine mucosa of rats

Os autores estudaram a cicatrizaçäo de feridas produzidas pelo laser CO2 na mucosa palatina do rato. A cicatrizaçäo ocorreu em uma semana, e a regiäo atingida foi ocupada por tecido conjuntivo neoformado e por epitélio. Foram notados os numerosos leucócitos polimorfonucleares e fibroblastos entre as fibras colágenas neoformadas