Eosinophil inflammation of the nasal mucosa

Introduction: Inflammatory diseases are very frequent and cause reasonable mortality. They are the major part in upper airway diseases in ENT. Eosinophil inflammation is a key feature in allergic rhinitis, asthma, nasal polyps and non-allergic rhinitis. The mechanism and the consequences of eosinophil inflammation are described in this review. Methods and Results: Eosinophils mature in bone marrow, mainly under the influence of IL-5 and eotaxin. Once mobilised to circulation, they accumulate in inflammatory sites by specific adhesion. VCAM-1 and other adhesion molecules are involved in this process. In the tissue, eosinophils get activated by different stimuli like immunoglobulin receptors and cytokines like IL-5. Activated eosinophils release toxic proteins, mediators and cytokines and thus trigger further inflammatory response. This leads to the late phase reaction and continuing inflammatory reaction. Eosinophils also interact with virus infections and have effects on nerve endings with the M2 receptor. Conclusions: Eosinophil inflammation may be monitored via the determination of cationic proteins in nasal secretions. Corticosteroids are very effective in the treatment of eosinophil inflammation, and anti-IL-5 and anti-IL-4 antibodies seem to be effective, too.