Related Experiment Videos
Pneumococcal middle ear fluid antibodies after pneumococcal acute otitis media in infants
P Karma1, M Sipilä, J Luotonen
1Department of Clinical Sciences, University of Tampere, Finland.
Insights
Infants with recurrent acute otitis media (AOM) can develop pneumococcal antibodies (Pn-abs) in middle ear fluid. This immune response may offer protection against specific pneumococcal types.
Area of Science:
- Otolaryngology
- Pediatric Infectious Diseases
- Immunology
Background:
- Acute otitis media (AOM) is common in infants.
- Recurrent or prolonged AOM can be caused by Streptococcus pneumoniae (Pn).
- The infant immune response in the middle ear during AOM requires further investigation.
Purpose of the Study:
- To investigate the presence and characteristics of pneumococcal antibodies (Pn-abs) in middle ear fluids (MEFs) of infants with initial and recurrent AOM.
- To determine the relationship between Pn-abs, pneumococcus (Pn), and pneumococcal antigens (Pn-ags) in MEFs.
- To understand the local immune response in the middle ear during pneumococcal AOM in infants.
Main Methods:
- Observation of 41 infants with culturable S. pneumoniae during initial AOM for 7-15 months.
- Analysis of middle ear fluids (MEFs) for the presence of Pn, Pn-ags, and Pn-abs.
- Categorization of Pn-abs by Ig-class and specific pneumococcal types.
Main Results:
- Pneumococcal antibodies (Pn-abs) were detected in 35% of MEFs during follow-up, often in low quantities across major Ig-classes.
- Pn-abs targeting types 3, 9N, and 14 were most frequently observed.
- While Pn-abs presence often correlated with the absence of initial Pn/Pn-ags, new Pn/Pn-ags could appear in recurrent MEFs.
Conclusions:
- Pneumococcal AOM can elicit a local immune response in the infant middle ear, involving pneumococcal antibodies.
- This immune response may provide protection against homologous pneumococcal strains.
- The presence of Pn-abs does not preclude non-homologous pneumococcal infections in the middle ear.
Abstract:
Forty-one infants, who during their first (initial) acute otitis media (AOM) had culturable S. pneumoniae (Pn) in 57 middle ear fluids (MEFs) which prolonged or recurred during the follow-up, were observed for 7-15 months for the presence of Pn, Pn-antigens (Pn-ags) and initial-type/group Pn-antibodies (Pn-abs) in these MEFs. Initially, Pn-abs were found in only 3 MEFs. During the follow-up a total of 20 ears (35%) were, at various time-intervals, positive for Pn-abs; they belonged to all three major Ig-classes, but were often slight in quantity. Most regularly, and often with distinct positivity, Pn-abs were found to type 3, 9N and 14. Secretory abs were detected in 5 ears. Within one month after initial AOM, Pn-abs appeared in 9 of the 41 ears with MEF (22%); six of them cleared soon after that. MEFs with Pn-abs usually did not show initial-type Pn/Pn-ag, but new Pn/Pn-ag could later be simultaneously present in recurrent MEF. So, pneumococcal AOM may cause a local and/or systemically mediated immune response in the middle ear in infants. The response may protect the ear from homologous, but still be present in apparently non-homologous otitis media.