Bronchoscopy was performed under light sedation with midazolam. Endoscopic bronchial biopsy samples were obtained from various segmental and subsegmental carinae of the right lung (Olympus Biopsy Forceps 35C; Olympus Medical Systems Corporation; Tokyo, Japan), fixed in formaldehyde and embedded in paraffin prior to cutting. A peroxidase-based method of staining was used as previously described18 using 5-μm sections. Immunostaining was performed using monoclonal antibodies for IL-4, IL-5, interferon (IFN)-γ, IL-8, and eotaxin (R&D Systems; Minneapolis, MN). Mouse IgG1 served as the isotype control for IL-4, IL-5, IL-8, and eotaxin, while mouse IgG2A was the isotype control for IFN-γ. StreptABComplex/HRP and DAB substrate (DakoCytomation) were used to develop the reactions according to manufacturer guidelines. Slides were examined and images acquired by a BX51 Olympus microscope attached to a CoolSNAP-Pro color digital camera (Carsen Group; Markham, ON, Canada) using Image Pro-plus 4.0 (Media Cybernetics; Silver Spring, MD). Scoring of epithelial staining for IL-8 and eotaxin, based on the percentage of the epithelium that stained positively, was performed as follows: 0 = no staining, 1 = 0 to 12.5%, 2 = 12.5 to 25%, 3 = 25 to 37.5%, 4 = 37.5 to 50%, 5 = 50 to 62.5%, 6 = 62.5 to 75%, 7 = 75 to 87.5%, and 8 = 87.5 to 100%. Subepithelial immunoreactive cells are reported as the number of cells that stained positively per field with a given antibody. The analysis was performed by an observer blinded as to group status.