Figure 4a. AEP in a 29-year-old man with 26% BAL fluid eosinophilia. (a) Chest radiograph obtained 7 days after the onset of dyspnea reveals reticular densities with patchy consolidation and ground-glass opacities in both lungs. (b) Thin-section (1-mm collimation) CT scan (lung windowing) shows multifocal patchy areas of ground-glass opacity and consolidation with smooth interlobular septal thickening (arrows) in both lower lobes. Bilateral pleural effusions are also seen. (c) High-power photomicrograph (original magnification, x400; H-E stain) of a transbronchial lung biopsy specimen obtained from the left lower lobe 5 days after a shows the infiltration of eosinophils (arrows) and lymphocytes into the alveolar spaces and alveolar walls. Note the absence of interstitial fibrosis.