IL13 is critical for inflammation-induced mucous cell expansion and metaplasia development. (A) H&E corpus sections showing the degree of inflammation, parietal cell atrophy, and mucous cell expansion in 3-month-old TxA23 (left) and 4-month-old TxA23 treated with isotype control (center) or anti-IL13 (right). Enlarged inlay section shown in top left corner. Scale bars: 200 μm. (B) Immunofluorescent staining with anti-GKN3 (red), GSII (green), and Hoechst (blue) showing SPEM development (GKN3+GSII+, yellow). Scale bars: 50 μm. (C) Disease scores of TxA23 mice at 3 months of age before treatment (blue), and 4 months of age after treatment with isotype control (red) or anti-IL13 (black). Each dot represents 1 mouse (N = 4–7). Significance was determined using the Mann–Whitney U test. Inflammation: ∗∗P = 0.003; Atrophy: ∗∗P = 0.01 ∗∗∗∗P < 0.0001; Neck Cell Expansion: ∗∗P = 0.002 ∗∗P = 0.007. (D) Quantification of SPEM+ (GKN3+) glands in 3-month-old TxA23 (blue) and 4-month-old TxA23 treated with isotype control (red) or anti-IL13 (black). Each dot represents 1 mouse (N = 4–7). Significance was determined using a Student t test. ∗P = 0.04 ∗∗∗P = 0.0001. Data show means ± SEM.