Evidence of mast cell activity in the middle ears of children with otitis media with effusion

Abstract

Mast cells and its mediator tryptase, both indicators of a Th2-driven immune response, are present in a majority of ears that have chronic effusion. These findings support the hypothesis that middle ear mucosa is capable of an allergic response and that the inflammation within the middle ear of most OME patients is allergic in nature.

Eosinophils and neutrophils in biopsies from the middle ear of atopic children with otitis media with effusion

“…Kähonen and coworkers [18] demonstrated the presence of T helper and T suppressor cells in patients with otitis media, and this was confirmed in later studies [19,20]. We have recently shown the increased presence of mast cells in the middle ear of patients with atopy and OME [21]. Palva and coworkers [19] also noted the presence of, often degranulated, polymorphonuclear leukocytes in otitis media patients.…”

Relationships between atopy and bacterial infections

“…It is probably related to bacterial infection because bacteria can be cultured from up to 33% of middle ear effusions (MEE) in patients with OME [29,30]. In a second study by Hurst et al [31], tryptase and eosinophilic cationic protein (ECP) were found to be significantly elevated in the effusions of patients with OME versus control patients with eustachian-tube dysfunction. Whereas 87% of patients with OME were found to be atopic versus 40% of the controls, 95% of the patients with elevated tryptase were atopic.…”

Participation of mast cells in chronic otitis media

“…Some studies have found increased number of MCs and higher levels of histamine in adenoid, which may indicate that mast cells are the source of inflammatory mediators for Eustachian tube and middle ear [13][14][15]. Increased counts of MCs and elevated tryptase levels, in effusion and in middle ear mucosa, have been demonstrated in allergic patients with OME [16,17]. Clinical studies reporting high histamine levels in middle ear effusion in secretory otitis media [12,18] and in acute otitis [19], as well as experimental studies of guinea pigs in which histamine injection into the tympanic cavity had caused long-standing effusion [20], also point to histamine participation in the pathomechanism of middle ear inflammation.…”

“…MCs are more abundant in the epithelium than in the subepithelial layer, as compared to adenoid [12]. The role of mast cells and their mediators, such as tryptase and histamine, has been assessed in pathology of the middle ear mainly in adenoid hypertrophy and otitis media with effusion (OME) [13][14][15][16][17]. Some studies have found increased number of MCs and higher levels of histamine in adenoid, which may indicate that mast cells are the source of inflammatory mediators for Eustachian tube and middle ear [13][14][15].…”