In the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP), Aspergillus fumigatus (A. fumigatus) can upregulate IL-33 from human sinonasal epithelial cells (SNECs), which then activates innate lymphoid cells causing release of IL-13, an important driver of allergic inflammation.
Furthermore, mechanistic studies suggest that the nongastric H,K-ATPase is necessary for IL-13-mediated epithelial responses, and its inhibitors, including PPIs, might be of therapeutic value in patients with CRSwNP by reducing epithelial production of eotaxin-3.
The demonstration that IFN-γ and IL-13 both significantly reduce ciliated cell differentiation and CBF in CRSwNP patients, and IL-13 additionally induces significant goblet cell hyperplasia and MUC5AC mucin expression, as well as IL-17 significantly increases MUC5B mucin expression, suggests that these inflammatory cytokines may be potential therapeutic targets in the management of CRSwNP.
An increased level of POSTN, IL-4, and IL-13 gene expression may be related to the development of chronic rhinosinusitis with nasal polyps, but polyp formation seemed to be associated especially with POSTN and IL-13 expression.
Moreover, the eosinophilic CRSwNP subset exhibited significantly decreased SPLUNC1 expression and numbers of submucosal glands, as well as significantly increased IL-4 and IL-13 mRNA levels, compared with the noneosinophilic subset (P < .05).