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Pneumococcal antigens and endotoxin in effusions from patients with secretory otitis media
1Department of Otolaryngology, University of Helsinki, Finland.
Abstract:
Counterimmunoelectrophoresis revealed pneumococcus capsular polysaccharide antigen in 16% of 108 effusions from chronic secretory otitis media (SOM). Pneumococci were cultured from the effusion in only 1%. In an additional series of 23 SOM ears, only 4.3% were antigen-positive. Tests by means of pneumococcal coagglutination and C-polysaccharide detection gave identical results. Endotoxin was detected in 76% of the specimens. Control tests with aggregated NHS, IgG and IgA diluted 1: 10 were invariably positive. It appears that endotoxin positivity in SOM fluids results from the presence of activated immunoglobulins, most probably dimeric IgA, in the secretion, and so allows no conclusions as to the bacterial etiology of SOM.
Insights
Pneumococcus antigen was found in 16% of middle ear effusions from chronic secretory otitis media (SOM), but bacteria were cultured in only 1%. Endotoxin detection in SOM fluids likely indicates activated immunoglobulins, not bacterial infection.
Area of Science:
- Otolaryngology
- Microbiology
- Immunology
Background:
- Secretory otitis media (SOM) is a common condition, often associated with middle ear effusions.
- The bacterial etiology of SOM remains debated, with varying reports on pathogen detection rates.
Purpose of the Study:
- To investigate the presence of pneumococcus antigen and endotoxin in middle ear effusions of chronic SOM.
- To determine the correlation between antigen detection, bacterial culture, and endotoxin presence in SOM.
Main Methods:
- Counterimmunoelectrophoresis (CIE) was used to detect pneumococcus capsular polysaccharide antigen in 108 middle ear effusions.
- Bacterial cultures were performed on effusions.
- Pneumococcal coagglutination and C-polysaccharide detection assays were utilized.
- Endotoxin detection was performed on specimens.
Main Results:
- Pneumococcus antigen was detected in 16% of effusions, while pneumococci were cultured in only 1%.
- An additional 23 SOM ears showed 4.3% antigen positivity.
- Endotoxin was detected in 76% of specimens.
- Control tests indicated that endotoxin positivity was linked to activated immunoglobulins, particularly dimeric IgA.
Conclusions:
- The presence of endotoxin in SOM fluids is likely due to activated immunoglobulins, not necessarily active bacterial infection.
- These findings suggest that endotoxin detection alone cannot confirm the bacterial etiology of SOM.
- Further research is needed to elucidate the precise role of bacteria and host immune responses in SOM pathogenesis.