Background: Allergic rhinitis is associated with Th2-dependent inflammation. Nasal obstruction is the most typical symptom in children with mite allergy.
Objectives: The aim of this study was to evaluate the possible relationships among nasal symptoms, allergic inflammation, including inflammatory cells and cytokine pattern, and nasal airflow in children with persistent allergic rhinitis because of mite sensitization.
Methods: Twenty children (13 males and seven females, mean age 13.4 ± 1.6 years) with persistent rhinitis because of mite allergy were evaluated. All of them had moderate–severe grade of nasal obstruction. Total symptom score (TSS), rhinomanometry, nasal lavage, and nasal scraping were obtained in all subjects. Inflammatory cells were counted by conventional staining; interleukin (IL)-5, and IL-8 were measured by immunoassay on fluids recovered from nasal lavage.
Results: Eosinophils were significantly associated with TSS (R = 74.4%, P = 0.0002), with IL-5 (R = 90.6%, P < 0.0001) and with nasal flow (R = −69%, P = 0.0007), but not with IL-8 (R = 0.1%, P = 0.995). Eosinophil levels were shown to independently predict nasal flow (P < 0.001), with flow decreasing linearly for increasing eosinophils, together with a significant effect of neutrophils (P = 0.016, linear increase in flow) and a borderline effect of IL-8 (P = 0.063, linear increase in flow).
Conclusions: This study demonstrates the close association between IL-5 concentration and eosinophil infiltration. In addition, there is clear evidence concerning the relationship between eosinophil infiltration and nasal airflow. Thus, nasal eosinophils can be regarded as the most important predictor of upper airway function. These findings constitute first evidence of the relationship between nasal airflow impairment and Th2-related eosinophilic inflammation in children with persistent allergic rhinitis because of mite sensitization.