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Published on: February 15, 2013
Pneumococcal antibody response in children with recurrent respiratory tract infections: A descriptive study
Falke Ceuppens1, Isabelle Meyts2, Xavier Bossuyt3
1Department of Paediatrics, University Hospital Leuven, Belgium.
Insights
Polysaccharide antibody deficiency affects over a quarter of children with recurrent respiratory infections, but doesn't correlate with illness severity. This finding aids in diagnosing susceptibility in pediatric patients.
Area of Science:
- Immunology
- Pediatrics
Background:
- Recurrent respiratory tract infections in children can indicate underlying polysaccharide antibody deficiency.
- Diagnostic evaluation includes assessing pneumococcal antibody response post-vaccination.
- Prevalence and therapeutic impact of this deficiency remain understudied.
Purpose of the Study:
- To determine the prevalence of polysaccharide antibody deficiency in children with recurrent respiratory infections.
- To correlate polysaccharide responsiveness with clinical severity.
- To examine the relationship between the IgG2/IgG ratio, IgA levels, age, and antibody deficiency.
Main Methods:
- Retrospective analysis of 103 children with recurrent respiratory infections.
- Assessed pneumococcal polysaccharide antibody titers (serotypes 8, 9N, 15B), clinical data, and immunoglobulin levels.
- Interpreted antibody response using American Academy of Allergy, Asthma, and Immunology guidelines.
Main Results:
- 27.2% of children were diagnosed with polysaccharide antibody deficiency.
- No correlation found between antibody deficiency and clinical severity.
- Higher IgG2/IgG ratio and older age were associated with normal polysaccharide responsiveness.
Conclusions:
- Diagnostic pneumococcal polysaccharide vaccination identified an underlying susceptibility mechanism in 18.4% of children with recurrent respiratory infections.
- Further research is needed for age-specific normal values for polysaccharide responsiveness.
- Investigating the utility of the IgG2/IgG ratio for diagnostic vaccination is recommended.
Background:
The pneumococcal antibody response after vaccination with unconjugated pneumococcal vaccine can be evaluated as part of the diagnostic work-up of children with recurrent respiratory tract infections to detect an underlying polysaccharide antibody deficiency. Little is known about the prevalence of polysaccharide antibody deficiency in this population and its therapeutic consequences.
Objectives:
This study aimed to investigate the prevalence of polysaccharide antibody deficiency in children with recurrent respiratory tract infections and to correlate polysaccharide responsiveness with clinical severity. In addition, we aimed to evaluate differences in the immunoglobulin (Ig)G2/IgG ratio, IgA level, and age in relation to the number of deficient serotype-specific antibody responses.
Methods:
Polysaccharide antibody titers for pneumococcal serotypes 8, 9N, and 15B; clinical characteristics; and immunoglobulin levels of 103 children with recurrent respiratory tract infections were retrospectively assessed. American Academy of Allergy, Asthma, and Immunology guidelines were used for the interpretation of the polysaccharide antibody response.
Results:
Overall, 28 children (27.2 %) were diagnosed with polysaccharide antibody deficiency. No correlation was found between the number of deficient serotype-specific antibody responses and clinical severity. The study participants with a normal response to all three serotypes had a higher IgG2/IgG ratio than those with one or more deficient responses (p < 0.003). No significant correlation between IgA levels and polysaccharide responsiveness was found. The median age of children with normal polysaccharide responsiveness for the three tested serotypes was higher than that of children with a deficient response to one or more serotypes (p < 0.0025).
Conclusion:
For a large group of children (18.4 %) with recurrent respiratory tract infections, an underlying mechanism for their susceptibility was defined thanks to diagnostic unconjugated pneumococcal polysaccharide vaccination. Further research is needed to formulate age-specific normal values for polysaccharide responsiveness and to investigate the usefulness of the IgG2/IgG ratio in determining the need for diagnostic unconjugated pneumococcal polysaccharide vaccination.
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