Confocal immunofluorescence images of lungs from a 4 month old donor control lung (A-D), Infant A (E-H) and Infant B (I-L). Nuclear NKX2.1 and cytoplasmic ABCA3 are co-expressed in AT2 cells (A-B), and nuclear HOPX is expressed in AT1 cells (C-D) in the normal control lung. In contrast, the distal saccules comprising the lobules in Infant A are lined by atypical epithelial cells with a discrepancy in NKX2.1 and ABCA3 expression (E-F), and lack of nuclear HOPX expression (G-H). Enlarged and simplified alveoli in Infant B are lined by AT2 cells co-expressing NKX2.1 and ABCA3 (I-J) and AT1 cells expressing nuclear HOPX, Original magnification: 20X objective with pixel size of 0.63 μm (A, C, E, G, I, K), 60X objective with pixel size of 0.21 μm (B, D, F, H, J, L).