Histologic analysis of murine peripheral airways. (A-C) Bronchoalveolar lavage cytospins obtained from sham-immunized (A) and OVA-immunized (B-C) mice were stained with CD41 immunoperoxidase and Gill hemotoxylin (A-B), or hemotoxylin and eosin (C). Note the presence of platelet aggregates (p; arrow) in cytospin from OVA-immunized mice (B). (D-I) Sections from distal airways of sham-immunized (D,G) and OVA-immunized (E,H) mice and OVA-immunized mice rendered thromobcytopenic following treatment with busulfan (F,I). Sections were stained with either Masson trichrome (D-F) or Gordon and Sweet silver stain (G-I). Red arrows in panel E indicate airway smooth muscle. Blue arrows in panels D-F indicate epithelium. White circles in panels G-I represent regions of subepithelial fiber deposition. Horizontal white bars represent 20.0 μm. Original magnifications: A,C-F, × 40 objective; B,G-I, × 100 objective.