At this time, while there are no FDA-approved biologics for use in NP, research has highlighted the contributions of IL-4, IL-5, IL-13, and IgE as disease mediators in the pathogenesis of NP.
Interestingly, the stimulation of cultured epithelial cells with Th2 cytokines, IL-4 and IL-5, resulted in an upregulation of CCL17 expression only in NP epithelial cells whereas the expression of CCL17 was increased in both normal epithelial cells and NP epithelial cells by Th1 cytokines.
Each is also associated with significantly distinct host immune responses; DSI, II, and III(b) invoked a variety of pro-inflammatory, T<sub>H</sub>1 responses, while DSIII(a), which exhibited significantly increased incidence of nasal polyps (Fisher's exact; p = 0.034, relative risk = 2.16), primarily induced IL-5 expression (Kruskal Wallis; q = 0.045).
We investigated the association of postoperative endoscopic findings with clinical parameters, mucosal eosinophil count and mRNA expression of CCL11, IL-5, and IFN-gamma in nasal polyps.
This study shows for the first time that IL-9 is involved in EO homeostasis in CRSwNP and could explain the low benefit of anti-IL-5 therapy for some patients with asthma and nasal polyposis.
In addition, we found that IL-33 induced upregulation of IL-5 by memory CD4(+) T cells isolated from nasal polyps of patients with eosinophilic chronic rhinosinusitis.
Since, TM-IL-5Ralpha is down-regulated and SOL-IL-5Ralpha (antagonistic) is upregulated in NP tissue, our findings are important to understand the clinical trials with anti-IL-5 in humans.
Expression of DP and CRTH2 in nasal polyps (NP) and uncinate process mucosae (UPM) was examined by in situ hybridization and immunohistochemistry and evaluated by real-time quantitative PCR. h-PGDS, IL-5, eotaxin and RANTES expression was also determined.