IL4 and cystic fibrosis: In marked contrast, baseline ASL pH in CF-T16AKO epithelia treated with IL-4 was significantly (P < 0.01) more alkaline (6.8 ± 0.6, n = 27, Fig. 2D) compared to CF-CTRL epithelia treated with IL-4, suggesting that TMEM16A indirectly contributed to the acidification of ASL pH under inflammatory conditions.