TLR7 and Nasal polyposis: However, the TLR7/8 agonist R848 triggers the induction of IL-33 in healthy epithelium only (23.2 ± 6.17, p < 0.05) and not nasal polyposis epithelium (1.57 ± 0.38), despite the IL-6 and IL-8 induction levels being similar between those two groups.