Characteristics of migrating cells in effusion of the middle ear in patients with "eosinophilic otitis media"

Otitis media with effusion (OME) is known to be a disease that frequently afflicts children. Recently, numerous reports of intractable OME associated with bronchial asthma have been reported, generally referred to as "eosinophilic otitis media". To comprehend the cause and pathogenesis of this disease, we conducted an electron-microscope analysis of the effusion. The subjects were 5 male and 1 female patients, 4 had aspirin-induced asthma and 2 had adult-onset asthma. The number of collapsed and intact eosinophils and other inflammatory cells in the middle ear effusion were counted, and their characteristics were reviewed. Most eosinophils in the middle ear effusion were collapsed, and a high percentage of eosinophils in the nasal discharge were also collapsed. The inflammatory cells were phagocytosed by macrophages at a high frequency in cases of otitis media with effusion, but only a low rate of phagocytosis was observed in cases with eosinophilic otitis media. It is known that necrotic cells are phagocytosed with difficulty, while apoptotic cells are phagocytosed easily by macrophages. Therefore, collapsed eosinophils persist for a long time in middle ear effusion and the released granule proteins from the eosinophils cause the tissue failure. Threfore, we believe that treatment directed at causing apoptosis of eosinophils can prevent exacerbation of the intractable inflammation in this condition.