Table 2.

Summary of the histological analysis and immunohistochemistry for 4-HNE protein adducts in the vital organs of patients deceased after aggressive COVID-19. The most common findings observed for all patients or for patients whose respective vital organs were most severely affected by SARS-CoV-2 infection are summarized.

	Organ Structure/Tissue Appearance	Inflammatory Cells	Immunohistochemistry for 4-HNE Protein Adducts	SOD2 Immunohistochemistry
Lungs	Edematous Diffuse alveolar damage Acute and chronic interstitial pneumonia	All types of leukocytes—mostly PMNs within blood vessels, otherwise mostly pulmonary macrophages and T lymphocytes	Very strong positivity of the blood vessels, pneumocytes, hyaline membranes, and edematous liquid Some inflammatory cells positive, mostly PMNs, alveolar macrophages positive	Observed in the smooth muscle cells of the blood vessel walls and less common in the endothelium and vascular contents Prominent in alveolar macrophages in interstitial pneumonia and DAD PMNs negative
Heart	Often fibrotic Occasional myocarditis	T lymphocytes around blood vessels and in edematous endomysia PMNs in the blood vessels	Strong positivity of blood vessels Positive cardiac muscle fibers Positive inflammatory cells	Positive muscle fibers
Brain	Edematous	Perivascular CD3-positive T cells PMNs and T lymphocytes within the blood vessels	Strong positivity of blood vessels and vascular content Very strong and diffuse immunopositivity in neurons Positive astroglia	Positive neurons and reactive astrocytes
Liver	Often steatosis Rarely centrilobular cyanosis	Not prominent	Positivity of the blood vessels Positive hepatocytes	Positive hepatocytes and epithelium of the bile ducts
Kidneys	Acute tubular necrosis, with necrotization of the epithelium of the proximal and distal canals Structure of the glomeruli and collecting ducts preserved	Inflammatory cells were not found	Strong positivity, but only in collective tubules	Positive glomerular cells and collecting ducts