Table 1.

Grading system used for pulmonary inflammation

Grade	Perivascular/Peribronchial Inflammation	Interstitial Inflammation
Zero	Nil	Nil
1	Scanty, only occasional cells present	Nil
2	Scattered small groups of cells, <3 cells depth	Nil
3	Infiltrates present around most bronchi and vessels, easily seen at magnification of ×400	Nil/very scanty
4	Infiltrates present around all bronchi and vessels, <5 cells depth	Nil/very scanty
5	Infiltrates present around all bronchi and vessels, 5–10 cells depth	Mild interstitial inflammation, <20% area involved
6	Infiltrates present around all bronchi and vessels, >10 cells depth	Mild interstitial inflammation, <50% area involved
7	Infiltrates present around all bronchi and vessels, >10 cells depth	Moderate interstitial inflammation, 50–80% area involved
8	Infiltrates present around all bronchi and vessels, >10 cells depth	Marked interstitial inflammation, >80% area involved