Table 2.

The histological description for FFPE lung samples used in this study.

Patient	Sample	Stage	Grade	Autopsy description
I	A	Early	1	Alveolar walls with obvious congestion. Alveolar spaces with early membranes (refer Fig. 1a).
II	B	Early	2	Alveolar spaces with early membranes. Obvious bacterial overgrowth.
III	C	Early	3	Alveolar spaces with some inflammation and membranes. Early intravascular thrombus formation (refer Fig. 1b).
III	D	Early	4	Alveolar spaces with some inflammation and membranes (more than in previous). No intravascular thrombus formation.
IV	E	Early	5	Alveolar spaces with some inflammation and membranes (more than in previous). No intravascular thrombus formation (Fig. 1c).
IV	F	Early	6	Membranes (more than previously, Fig. 1d and e), giant cells (Fig. 1f) and vascular changes.
V	G	Late	7	Some areas relatively unaffected, other with BOOP-like appearance (Fig. 1g).
VI	H	Late	8.1	Intra-alveolar fibrosis and consolidation (Fig. 1h). Giant cells appearance.
VI	I	Late	8.2	Intra-alveolar fibrosis and consolidation, with giant cells. Early thrombus formation.
VII	J	Late	9	Extensive intra-alveolar fibrosis and consolidation. Early thrombus formation.
V	K	Late	10	Increased fibrosis and consolidation (refer Fig. 1j).
VII	L	Late	11	Fully established fibrosis and consolidation.