The formalin-infused lungs were embedded in paraffin wax
blocks and sliced into 6 lm-thick sections. The slides were
examined under a light microscope after staining with haematoxylin
and eosin. The scoring of the airway inflammation was
blindly investigated by two separate investigators. A standard
scale (0–3) was used to evaluate the severity of perivascular
and peribronchial inflammation (Park et al., 2001) and to
assign value: 0 for no evident inflammation, 1+ for foci or
infrequent cuffing with inflammatory cells, 2+ if most bronchi
or vessels were surrounded by a thin layer, and 3+ for the
most severe inflammation (more than five cells deep) of inflammatory
cells. The average of the peribronchial and perivascular
inflammation scores was used to define total lung
inflammation.