Localised inflammation found in eosinophilic otitis media

By Joanna Lyford, Senior medwireNews Reporter

Antigen-specific immunoglobulin (Ig)E is produced locally in the middle ear mucosa of patients with eosinophilic otitis media (EOM), clinical research indicates.

The study further demonstrates that IgE is produced in the middle ear in response to bacterial and fungal antigens and that local sensitisation may influence the severity of clinical EOM.

The findings are reported by Yukiko Iino (Jichi Medical University Saitama Medical Center, Japan) and team, who studied 26 patients (13 women, mean age 54.3 years) with EOM associated with bronchial asthma and nine healthy controls.

Samples of serum and middle ear effusion were analysed for antigen-specific IgEs, while nasopharynx and middle ear effusion samples were analysed for bacterial and fungal infection.

Writing in the Annals of Allergy, Asthma & Immunology, the authors report that at least one antigen-specific IgE was present in serum in 20 of the 26 patients.

In the middle ear effusion, at least one antigen-specific IgE was found in 16 (62%) of the EOM patients versus just one (11%) of the healthy controls. This difference was statistically significant.

Interestingly, the mean IgE level in serum was not significantly different between patients who tested positive versus those who tested negative for antigen-specific IgE. Also, while 11 patients tested positive for fungal antigens in their middle ear effusion, none of these patients had fungi-specific IgE in their serum.

Finally, EOM severity score – based on assessment of five clinical variables – was significantly higher in patients with antigen-specific IgE in their middle ear effusion than in those without, at 8.8 versus 4.9.

Iino et al say their findings suggest that IgE may be locally produced in the middle ear mucosa rather than being derived from serum, and that locally produced IgE may play an important role in the pathogenesis of EOM regarding eosinophilic inflammation in the middle ear and damage to the inner ear.

They add: “In this study, we also found that the presence of antigen-specific IgE in [middle ear effusion] was closely related to the severity of EOM. This finding is consistent with the fact that in eosinophilic inflammatory diseases of the respiratory tract, such as bronchial asthma and nasal polyposis, local production of IgE is a crucial factor for developing and exacerbating eosinophilic inflammation in the middle ear and affecting the severity of EOM.”

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