Eosinophil recruitment to nasal nerves after allergen challenge in allergic rhinitis

In allergen challenged animal models, eosinophils localize to airway nerves leading to vagally-mediated hyperreactivity. We hypothesized that in allergic rhinitis eosinophils recruited to nasal nerves resulted in neural hyperreactivity. Patients with persistent allergic rhinitis (n = 12), seasonal allergic rhinitis (n = 7) and controls (n = 10) were studied. Inferior nasal turbinate biopsies were obtained before, 8 and 48 h after allergen challenge. Eight hours after allergen challenge eosinophils localized to nerves in both rhinitis groups; this was sustained through 48 h. Bradykinin challenge, with secretion collection on the contralateral side, was performed to demonstrate nasal nerve reflexes. Twenty four hours after allergen challenge, bradykinin induced a significant increase in secretions, indicating nasal hyperreactivity. Histological studies showed that nasal nerves expressed both vascular cell adhesion molecule-1 (VCAM-1) and chemokine (C-C motif) ligand 26 (CCL-26). Hence, after allergen challenge eosinophils are recruited and retained at nerves and so may be a mechanism for neural hyperreactivity.

► Eosinophils are prominent in the nasal tissue of patients with rhinitis. ► Eosinophils localize to nasal nerves in allergen challenged patients with rhinitis. ► Interaction occurs in association with the induction of nasal nerve hyperreactivity.