Preliminary study of proinflammatory cytokines and chemokines in the middle ear of acute otitis media due to Alloiococcus otitidis.

Alloiococcus otitidis is a newly discovered organism frequently detected in otitis media. However, the association of the organism with the development of otitis media has not been disclosed in detail yet. In the middle ear, proinflammatory cytokines and chemokines are released in association with infection by pathogens, and these cytokines contribute to the induction of an inflammatory reaction. To investigate the profile of inflammation-related cytokines in the acute phase of A. otitidis infection, we analyzed the release of proinflammatory cytokines and chemokines in middle ear effusions of acute otitis media due to A. otitidis, in comparison with acute otitis media due to the well-known Gram-positive middle ear pathogen Streptococcus pneumoniae. The amounts of proinflammatory cytokines (IL-8, IL-1beta, IL-6, TNF-alpha) and CXC chemokines (IP-10, I-TAC) were significantly increased in the A. otitidis group as well as in the S. pneumoniae group. Various inflammation-related cytokines/chemokines were induced in the A. otitidis-infected middle ear, and the profile of cytokines was very similar to that in S. pneumoniae infection. This preliminary study suggests that A. otitidis has the potential to induce these cytokines, contributing to the development of an inflammatory reaction in the middle ear cavity in a similar manner to S. pneumoniae.