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Selective deficiency in pneumococcal antibody response in children with recurrent infections
1Yale University Department of Medicine, New Haven, Connecticut, USA.
Insights
Children with recurrent respiratory infections and low pneumococcal antibody titers were studied. Most responded to vaccination, but a distinct group showed an isolated defect in antibody production.
Area of Science:
- Pediatric Immunology
- Vaccinology
- Infectious Diseases
Background:
- Recurrent respiratory infections in children can indicate immune deficiencies.
- Impaired response to Streptococcus pneumoniae polysaccharide antigens is linked to IgG subclass deficiency.
Purpose of the Study:
- Identify children over three with recurrent infections and low pneumococcal antibody titers as sole immune deficiency sign.
- Assess their response to the 23-valent pneumococcal vaccine.
Main Methods:
- Studied 100 children with low pneumococcal antibody titers.
- Administered the 23-valent pneumococcal vaccine.
- Measured antibody titers post-vaccination.
Main Results:
- 87% of children achieved protective antibody response (> 300 ng/mL).
- 13% responded poorly or not at all to the vaccine.
- Repeated vaccination did not improve response in nonresponders.
Conclusions:
- Identified two distinct subpopulations based on pneumococcal vaccine response.
- A 6.5% subpopulation showed an isolated defect in anti-pneumococcal antibody production.
- This defect is associated with recurrent respiratory infections despite normal IgG2 levels.
Background:
Impaired ability to respond to polysaccharide capsular antigens of Streptococcus pneumoniae may be associated with an IgG subclass deficiency and recurrent respiratory infections.
Objective:
To identify children over three years of age with recurrent otitis media, sinusitis, or pneumonia who had low or absent pneumococcal antibody titers as their sole manifestation of immune deficiency and to determine their response to the 23-valent pneumococcal vaccine.
Results:
Of 100 children with low pneumococcal antibody titers, 87 generated a protective antibody response to the pneumococcal vaccine (> 300 ng/mL to the majority of the antigen serotypes), while 13 responded poorly or not at all. Repeated vaccination of nonresponders failed to produce a normal response.
Conclusion:
We have identified two clinically distinct subpopulations of children with recurrent respiratory infections characterized by their responsiveness to pneumococcal antigens: one group did not respond to pneumococcal vaccination, whereas the other group responded both clinically and serologically. The nonresponding 6.5% subpopulation has an apparent isolated defect in anti-pneumococcal antibody production associated with recurrent respiratory infections despite normal IgG2 subclass levels.