CD11c(+) dendritic cells coexpressing thymic stromal lymphopoietin receptor in animal model of eosinophilic otitis media.

Eosinophilic otitis media (EOM) is an intractable middle ear disease often associated with eosinophilic inflammatory airway conditions. Recently, dendritic cells (DCs) have been indicated as an essential component of Th2 allergic inflammation, such as bronchial asthma. DCs are activated by thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine. However, the relationship between TSLP and DCs in EOM remains unknown. This study aimed to investigate the relationship between DCs and TSLP and to determine the involvement of DCs in EOM in an animal model. Hartley guinea pigs were used as the animal model. Daily ovalbumin (OVA) stimulation of the middle ear was performed for 7 or 14 days. The temporal bone was dissected on the last day of stimulation, and paraffin-embedded sections were prepared. Immunostaining and immunofluorostaining for TSLP receptor (TSLPR) and CD11c, a surface marker of DCs, were performed. We found CD11c-immunopositive cells in the submucosal area of the middle ear epithelium, particularly around the eustachian tube. TSLPR-immunopositive cells exhibited a similar distribution as CD11c-positive cells. CD11c positive DCs coexpressing TSLPR were recruited after OVA challenge which might activate Th2 allergic reaction.