[Histological pulmonary features due to the Sars-CoV-2]. / Les lésions histologiques pulmonaires associées à l'infection par le Sars-CoV-2.

The histological lesions associated with an infection with the Sars-CoV-2 are mainly observed at the respiratory tract level, but not exclusively. Analyses of these lesions strongly beneficied from autopsic studies allowing us to improve the knowledge of the pathophysiology mechanisms of this emerging infectious disease. Cytological analyses, notably those obtained from broncho-alveolar lavages, poorly contribute to the Covid-19 diagnosis, but can be usefull for eliminate a couple of differential diagnoses. Although non specific, the lesions observed in the pulmonary parenchyma can be directly associated with the presence of the Sars-CoV-2 thanks to ancillary tools allowing its detection. Indeed, the presence of the virus can be detected using immunohistochemistry, in situ hybridization, molecular biology and/or electron microscopy approaches. Several uncertainties still exist concerning the direct role due to the Sars-CoV-2 in the observed lesions which can be due too to a cardiovascular failure and/or to the treatment(s) received in intensive care units. Thus, it is critical to keep going to increase our efforts for the tissue analyses, notably thanks to the autopsies of Covid-19 patients, in order to better understand the consequences of this infectious disease, and, particularly according the epidemiological factors and the different associated morbidities. An increased knowledge will participate to the further therapeutic strategies against the Covid-19. This review adresses the main histological lesions of the lung parenchyma currently described in patients infected by the Sars-CoV-2.

[Histopathological features due to the SARS-CoV-2]. / Les lésions histologiques associées à l'infection par le SARS-CoV-2.

The infection due to the SARS-CoV-2 leads lesions mainly observed at the respiratory tract level, but not exclusively. The analyses of these lesions benefited from different autopsy studies. Thus, these lesions were observed in different organs, tissues and cells. These observations allowed us to rapidly improve the knowledge of the pathophysiological mechanisms associated with this emergent infectious disease. The virus can be detected in formalin fixed paraffin embedded tissues using immunohistochemistry, in situ hybridization, molecular biology and/or electron microscopy approaches. However, many uncertainties are still present concerning the direct role of the SARS-CoV-2 on the different lesions observed in different organs, outside the lung, such as the heart, the brain, the liver, the gastrointestinal tract, the kidney and the skin. In this context, it is pivotal to keep going to increase the different tissue and cellular studies in the COVID-19 positive patients aiming to better understanding the consequences of this new infectious disease, notably considering different epidemiological and co-morbidities associated factors. This could participate to the development of new therapeutic strategies too. The purpose of this review is to describe the main histological and cellular lesions associated with the infection due to the SARS-CoV-2.