The novel coronavirus pneumonia COVID-19 caused by SARS-CoV-2 infection could lead to a serious of clinical symptoms and severe illness, including acute respiratory distress syndrome (ARDS) and fatal
organ failure.

The authors report the fundamental pathological investigation in the lungs and other organs of fatal cases after the autopsy and pathological investigations of specimens performed on bodies of two deceased cases with COVID-19.

The main pathological features in lungs included extensive impairment of type I alveolar epithelial cells and atypical hyperplasia of type II alveolar cells, with formation of hyaline membrane, focal hemorrhage, exudation and pulmonary edema, and pulmonary consolidation. The mucous plug with fibrinous exudate in the alveoli and the dysfunction of alveolar macrophages were characteristic abnormalities. The type II alveolar epithelial cells and macrophages in alveoli and pulmonary hilum lymphoid tissue were infected by SARS-CoV-2. S protein of SARS-CoV-2 directly bound to the macrophage via the S-protein-ACE2 interaction.

The authors conclude that infection of Alveolar macrophage by SARS-CoV-2 might be drivers of the “cytokine storm”, which might result in damages in pulmonary tissues, heart and lung, and leading to the failure of multiple organs .