Table 1.
Histology Scoring Criteria.
| Inflammation in different sites |
| Blood vessel region inflammation |
| ++ Some blood vessels are cuffed by inflammatory cells ++++ Most blood vessels are surrounded by a thin layer (1–5 cells thick) of inflammatory cells ++++++ Most blood vessels are surrounded by a thick layer (>5 cells thick) of inflammatory cells |
| Pulmonary alveoli inflammation |
| ++ Increased numbers of inflammatory cells in alveolar walls are evident ++++ As above, plus one to three foci per section showing alveolar exudate and atelectasis ++++++ As above, plus more than three foci per section showing alveolar exudate and atelectasis |
| Lung tissue inflammation |
| ++ Some blood vessels are cuffed by inflammatory cells ++++ A part of lung tissue shows consolidation and interstitial fibrous tissue proliferation ++++++ Consolidation appears in most areas of the lung |
| Bronchial inflammation |
| ++ Some bronchus are cuffed by inflammatory cells ++++ Some bronchus exhibit squamous metaplasia and are blocked by inflammatory exudates ++++++ Most bronchus exhibit squamous metaplasia and are blocked by inflammatory exudates |
The three levels of inflammatory response for each index, which was designated as ++, ++++ and ++++++, according to the criteria listed in the above table. The milder inflammation was designated with reduced number of “+” as indicated in respective Figures. To warrant the objectivity of the histology scoring, two pathologists from different labs read each slide in a double-blinded way and an average value was taken as the final result.