Table 1 Scoring system for the severity and characteristics of (a) lung gross pathology and histopathology (H&E staining) and (b) for level of SARS-CoV-2 antigen expression in the lungs (modifications in comparison with the previously described system51 are indicated with cursive)
(a) Parameter | Score | Extent of lesions |
|---|---|---|
General scores | ||
Gross pathology | 0 | No macroscopical changes |
1 | Focal discoloration of the lung in <15% of lung surface | |
2 | Multifocal discoloration of approximately 15–40% of lung surface | |
3 | Multifocal discoloration affecting approximately 40–70% of lung surface | |
4 | Whole lung affected in >70% of lung surface | |
Extent lung histopathology (general score, percentage) (H&E) | 0 | No changes |
1 | Focal to multifocal (<15% of tissue) | |
2 | Multifocal (15–40% of tissue) | |
3 | Multifocal to coalescing discoloration (40–70% of tissue) | |
4 | Diffuse (>70% of tissue) | |
Individual histological parameters (severity) | ||
Alveoli - (thickening alveolar wall, type II pneumocyte proliferation, inflammatory cells alveoli)/ interstitial pneumonia | 0 | No changes |
1 | Focal to multifocal (<20% of tissue) | |
2 | Multifocal (20–50% of tissue) | |
3 | Multifocal to coalescing (>50% of tissue) | |
Bronchi and bronchiole | 0 | No changes |
1 | Peribronchiolar infiltrate or in lumina with no or mild epithelial degeneration < 20% of bronchi/bronchioles | |
2 | Peribronchiolar infiltrate or in lumina with mild to moderate epithelial degeneration > 20–50% of bronchi/bronchioles | |
3 | Peribronchiolar infiltrate or in lumina with severe epithelial degeneration and necrosis > 50% of bronchi/bronchioles | |
Blood vessels | 0 | No changes |
1 | Perivascular clear spaces (edema) with only mild infiltrates of inflammatory cells > 15% of large blood vessels | |
2 | Clear perivascular cuffing in > 15–30% of blood vessels, with occasionally presence of inflammatory cell in blood vessel wall without clear degeneration | |
3 | Extensive perivascular cuffing often of more than 5 cell layers, also in large arteries with clear Infiltrates of inflammatory cells in blood vessel walls | |
Hemorrhage/hemosiderophages (macrophages with hemosiderin) | 0 | No hemorrhage/hemosiderophages |
1 | Mild focal to multifocal hemorrhage/hemosiderophages | |
2 | Moderate to severe multifocal hemorrhage/hemosiderophages | |
(b) Parameter | Score | Extent of lesions |
Level of antigen expression (IHC) | 0 | No staining |
1 | Focal or multifocal staining (<5 foci) en < 15% of tissue | |
2 | Multifocal staining in 15–40% of the tissue | |
3 | Multifocal to coalescing staining in > 40–70% of the tissue | |
4 | Diffuse staining in > 70% of the tissue | |
