Table 1.

Histopathologic grades of the lung.

	Grade 0	Grade 1	Grade 2	Grade 3
Apoptotic bodies in bronchi walls	None	Mild	Moderate	Severe
Intra-alveolar hemorrhage	None	Mild	Moderate	Severe
Vasculitis	None	Mild	Moderate	Severe
Peribronchial inflammation	None	Mild	Moderate	Severe
Perivascular inflammation	None	Mild	Moderate	Severe
Bronchopneumonia	None	Mild	Moderate	Severe
Perivascular edema	None	Mild	Moderate	Severe
Parenchymal edema	None	Mild	Moderate	Severe