Fig. 1

Histological changes in case 1. a Exudative phase of acute interstitial pneumonia (hematoxylin and eosin stain, × 100). b Detail of an alveolar septum with edema, hemorrhage and inflammatory cell infiltrations (green arrow: lymphocyte; yellow arrow: macrophage; brown arrow: fibroblast; blue arrow: polymorphonuclear leukocyte; black arrow: type II hyperplastic pneumocyte) (hematoxylin and eosin stain, × 400)