Proliferating Cells in Secretory Otitis Media

Cellular events in relation to bacteria-specific antibodies in middle ear effusion during acute otitis media

The proportions of neutrophils and lymphocytes, the total number of viable lymphocytes and their spontaneous proliferating activity as well as the proportion of B-cells were determined in 238 middle ear effusion (MEE) samples from 124 ears and in 40 serum samples of 85 children in relation to the presence of bacteria-specific antibodies in MEE and the clinical outcome of acute otitis media (AOM) during the course of AOM. The percentage of lymphocytes was higher, and that of the neutrophils lower, in the ears with bacteria-specific antibodies than in the ears with no antibodies. The higher proportion of MEE lymphocytes and the presence of antibodies correlated to the faster resolution of AOM. Moreover, the total number of viable lymphocytes and the proliferating activity of these cells were related to the presence of specific antibodies in MEE. The findings of this study underline the importance of local mucosal immunity taking place in the middle ear in connection with bacteria-specific antibodies in resting AOM.

How long do middle ear pathogens survive in mucoid effusion material?

Middle ear pathogens (S. pneumoniae, H. influenzae, B. catarrhalis, S. aureus and coagulase-negative staphylococci) were injected into 28 samples of mucoid effusion materials taken from 17 patients suffering from secretory otitis media. In every case the effusion material was sticky, hydrophilic and thick and contained no bacteria. S. pneumoniae and H. influenzae survived for only 1-2 days in mucoid effusion material incubated at 37 degrees C, while B. catarrhalis and staphylococci survived for at least 18-36 days when incubated in this medium. It seems that mucoid effusion material filling the middle ear cavity during secretory otitis media has a dual function in providing protection against middle ear infections. Thanks to its physical properties the effusion material hinders bacteria from ascending from the nasopharynx and is a poor substrate for some microorganisms. In contrast, mucoid effusion material is a superior medium for B. catarrhalis and staphylococci.

Colonization of middle ear pathogens in the nasopharyngeal opening of the Eustachian tube during secretory otitis media

Colonization of middle ear pathogens (S. pneumoniae, H. influenzae and B. catarrhalis) in the nasopharyngeal opening of the Eustachian tube (NO) was charted in 94 patients (170 ears) suffering from secretory otitis media (SOM). Subsequent determination of microorganisms in the middle ear effusion was performed. 76% of the patients had colonization of pathogens in the NO, while pathogens colonized the middle ear cavity (MEC) in 30% of the cases. Predominant pathogen was S. pneumoniae, followed by B. catarrhalis and H. influenzae. When colonizing the MEC, there was a 100% correlation to NO regarding B. catarrhalis, 81% correlation for S. pneumoniae and 57% for H. influenzae. S. aureus and/or coagulase-negative staphylococci were only occasionally found in the NO. Accumulation of a sticky glue effusion material in the middle ear cavity may serve as a barrier against ascending pathogens from the nasopharynx.

Collagenase activity in middle ear effusions

Collagenolytic enzyme activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Collagenase activity was characterized using different biochemical techniques. Various chemical and physical parameters were titrated for optimal enzyme activity. Bivalent cations activated the enzyme with Ca2+ as the most potent activator. Chelators such as EDTA reduced the enzyme at low concentrations. The enzyme was found to have a higher specific activity in mucoid effusions than in serous and had characteristics similar to granulocyte derived collagenase from human leukocytes. Possible relationships between the presence of collagenase activity and tissue destruction in the middle ear after otitis media with effusion are discussed. The collagenase activity showed wide ranges within different categories of middle ear effusions.

Aspects of biological potentials of mononuclear cells in middle ear effusions

Mononuclear phagocytes are cells common in the subepithelial space of the mucosa of the middle ear and in middle ear effusion during an attack of otitis media. Here we review studies to date on biological potentials of aural macrophages in the pathogenesis of otitis media. The origin of aural macrophages may be in the circulating pool of monocytes in the blood, in the pre-existing population of macrophages in the mucosa of the middle ear, in proliferation of macrophages in the middle ear, or in nasopharyngeal and tonsillar tissues. Macrophages demonstrate great phagocytic activity in eliminating tissue-debris, bacteria, and viruses. It seems likely that the secretory products of macrophages--such as lysozyme, components of complement, prostaglandins, collagenase, and other biologically active agents--play an important part in the pathogenesis of otitis media. There is also evidence available that aural macrophages play an important role in the regulation of lymphocytic response to antigens in active otitis media.

Biochemical pathology of otitis media with effusion

The sequential cytologic and biochemical events of middle ear effusion (MEE) were studied in experimental models of serous otitis media (SOM) and purulent otitis media (POM) in chinchilla. In the SOM model, the initial appearance of neutrophils was followed by macrophages. In the POM model, neutrophils were the predominant cells in MEE and the number of neutrophils was about 100-fold higher than in the SOM model. The activity of lysozyme in MEE was higher in POM than in SOM and correlated with the number of neutrophils and mononuclear phagocytes. The results of the present study suggest that neutrophils and mononuclear phagocytes are one of the main sources for lysozyme levels in MEE during otitis media.

Inflammatory cells in mucoid effusion of secretory otitis media

Inflammatory cells were studied in 269 mucoid middle ear effusions of 202 patients with secretory otitis media (SOM). Although the effusions contained inflammatory cells in all cases, the number of cells, the proportion of viable cells and the proportions of different cell types showed marked heterogeneity. However, the effusions formed a sliding scale with regard to the above cellular parameters. We suggest that these differences in the cellular picture might reflect differences in immune mechanisms and responses in the different effusions, possibly representing different phases of the course of an established SOM. In the subgroups of patients with cleft palate (22) or atopy (16) the cellular picture resembled that seen in the other patients (164), with the exception that the effusions of the cleft palate patients were somewhat more lymphocytic. Thus, from the immunological point of view, the effusions in established SOM seem to behave similarly, irrespective of the differences in the etiological background of SOM.