The degree of lung histopathology. Representative postmortem lung tissue samples showing typical minimal, moderate, and severe injury. The typical scores for tissue injury and inflammation in the right infected lung and left nonbacteria-challenged lung with older and newer blood transfusions are as follows: On the left, for nonbacteria-challenged lungs of these animals, the tissue injury scores (hemorrhage, necrosis, thrombosis) were median (range), older blood group 2 (1,2), and newer blood group 2 (1,4); on the right, for infected lungs, the scores were older blood group 3 (1,4) and newer blood group 2 (2,4). On the left, for nonbacteria-challenged lung of these animals, the inflammatory injury scores (neutrophils and fibrin deposition) were older blood group 4 (2,5) and newer blood group 4 (2,5). On the right, for infected lungs, the inflammatory injury scores were older blood group 4 (3-5) and newer blood group 4 (4-6).