Fig 1: Increased Ach levels in eCRSwNP, predominantly derived from SCC. (A) Histogram showing relative mRNA expression of ChAT and VAchT in bulk RNA‐seq. (B) Histogram showing relative mRNA expression of ChAT and VAchT in control, neCRSwNP, and eCRSwNP tissues through qRT‐PCR analysis (n = 6 per group). (C) Immunohistochemical staining showing ChAT expression in tissues from control, neCRSwNP, and eCRSwNP groups. (D‐E) Histogram showing ChAT immunoreactivity and positive staining areas in each group of tissues (n = 8 per group). (F) IF staining of ChAT (red) and the neuronal marker βIII Tublin (green) in control and eCRSwNP tissues. (G) Histogram showing CHAT+βIII Tublin+ cell numbers in subepithelium (n = 8 per group). (H) IF staining of ChAT (red) and the SCC marker GNAT3 (green) in control and eCRSwNP tissues. (I) Histogram showing CHAT+GNAT3+ cell numbers (n = 8 per group). (J) IF staining showing co‐localization of ChAT (red) with CC marker FOXJ1 (green), GC marker MUC5AC (red), BC marker P63 (green), and SCC marker GNAT3 (green) in ALI cultures. (K) Histogram showing Ach concentrations in the basolateral medium of ALI cultures under the following conditions: Untreated, α‐NETA‐treated, and IL‐4/IL‐5/IL‐13 treatment with or without α‐NETA, as measured by ELISA (n = 3 per group). Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.