IL4 and cystic fibrosis: However, under inflammatory conditions, resting ASL pH was significantly more acidic (P < 0.0001) in CF-26A4KO epithelial (6.1 ± 0.4, n = 12, Fig. 4C), compared to IL-4-treated CF-CTRL epithelia (6.6 ± 0.5, n = 12, Fig. 4C), and CF-CTRL epithelia under normal conditions (6.6 ± 0.3, n = 12, Fig. 4C).