Fig. 2

Pathological findings of lung biopsy specimens. A Lymphocytes and hyperplasia of type II pneumocytes infiltrate the alveolar walls (hematoxylin and eosin staining, ×40). B A high magnification of an area of a square of A shows few eosinophils. Fibrinous exudates and floating macrophages are observed in the alveolar lumina (hematoxylin and eosin staining, ×200). C, D Immunohistochemistry of biopsy specimens with CD4 (C) and CD8 (D) stains shows more CD4⁺ lymphocytes than CD8⁺ lymphocytes (×100). E, F Immunohistochemistry of biopsy specimen with CD4 (E) and Foxp3 (F) stains shows few CD4⁺ Foxp3⁺ lymphocytes (×100). Scale bar = 500 µm in (A), 50 µm in (B), and 100 µm in (C, F). The sections were observed with a microscope: Axio Scope A1 (Zeiss, Oberkochen, Germany), lenses: Plan-Apo × 5, 10, 20 (Nikon, Tokyo, Japan), a camera: FLOVEL Model FR-630 M (FLOVEL CO, LTD, Tokyo Japan), and a photo system: FLOVEL Image Filling system (FLOVEL CO, LTD, Tokyo, Japan)