IL5 and chronic rhinosinusitis: In addition, biopsies performed in the olfactory epithelium of patients diagnosed with chronic rhinosinusitis demonstrate higher concentrations of interleukin (IL)-5, IL-6, IL-8, and TNF-α compared with those from a control group (Lennard et al. 2000), and mucus cytokines levels (IL-5, IL-6, and TNF-α) in the olfactory cleft are negatively associated with olfactory dysfunction (Wu et al. 2018; Soler et al. 2020).