COVID-19 Lung Pathogenesis in SARS-CoV-2 Autopsy Cases

Area of Science:

• Pulmonary Pathology
• Immunology
• Virology

Background:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a multi-systemic disease linked to immune dysregulation and cytokine storms.
• Understanding lung pathology in fatal COVID-19 is crucial but limited by safety concerns regarding post-mortem tissue analysis.

Purpose of the Study:

• To characterize the lung pathology, immune response, and tissue damage in fatal COVID-19 cases.
• To identify distinct phenotypes of SARS-CoV-2-induced lung injury.

Main Methods:

• Analysis of post-mortem lung tissues from COVID-19 fatalities and uninfected controls.
• Integrated approach using histology, multi-viral/host marker staining, correlative microscopy, confocal imaging, and image analysis.

Main Results:

• Identified three distinct COVID-19 lung damage phenotypes: hemorrhage with thrombus, immune infiltration without hemorrhage, and a combined phenotype.
• Observed alveolar wall integrity loss, tissue detachment, fibroblast proliferation, and extensive fibrosis across all phenotypes.
• Detected significant B cell and poor T cell infiltration, suggesting a compromised immune response in lethal COVID-19.

Conclusions:

• SARS-CoV-2-induced lung damage is highly heterogeneous, with distinct pathological phenotypes.
• The observed immune cell infiltration patterns suggest an exhausted or compromised cellular immune response in fatal cases.
• Understanding this heterogeneity is vital for comprehending acute and long-term COVID-19 consequences.