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Impaired antibody response to Haemophilus influenzae type b polysaccharide and low IgG2 and IgG4 concentrations in
G R Siber1, M Santosham, G R Reid
1Laboratory of Infectious Diseases, Dana-Farber Cancer Institute, Boston, MA 02115.
Insights
Apache children show a significantly impaired antibody response to Haemophilus influenzae type b polysaccharide vaccines compared to white children. This immunodeficiency may contribute to the higher infection rates observed in this population.
Area of Science:
- Immunology
- Pediatrics
- Infectious Diseases
Background:
- Native American children face a higher risk of invasive Haemophilus influenzae type b infections.
- Previous studies indicated disparities in infection rates, necessitating further investigation into immune responses.
Purpose of the Study:
- To compare antibody responses to Haemophilus influenzae type b polysaccharide vaccine in healthy Apache and white children.
- To investigate potential immunodeficiencies contributing to increased infection risk.
Main Methods:
- Comparative analysis of antibody concentrations post-vaccination in Apache and white children.
- Assessment of immunoglobulin classes (IgG, IgM, IgA) and subclasses (IgG2, IgG4).
- Evaluation of antibody responses to protein toxoids (tetanus, diphtheria).
Main Results:
- Apache children exhibited approximately 10-fold lower antibody concentrations to H. influenzae type b polysaccharide vaccine.
- Impaired response was observed across IgG, IgM, and IgA antibody classes.
- While total immunoglobulin levels were higher in Apache children, specific subclasses (IgG2, IgG4) were lower, indicating a targeted immunodeficiency.
Conclusions:
- Apache children possess a significant impairment in antibody response to H. influenzae type b polysaccharide.
- The observed immunodeficiency is specific to polysaccharide antigens, with minimal impact on protein toxoid responses.
- This impaired immune response is a likely factor explaining the high incidence of H. influenzae type b infections in Apache children.
Background And Methods:
Because Native American children are at much higher risk for invasive Haemophilus influenzae type b infection than white children, we compared the antibody responses to H. influenzae type b polysaccharide vaccine in healthy Apache and white children.
Results:
The concentrations of H. influenzae type b antibody after immunization with polysaccharide vaccine were approximately 10-fold lower in 24-month-old Apache children than in whites of a similar age (P less than 0.01). The decreased response involved H. influenzae type b antibodies of the IgG, IgM, and IgA classes. Concentrations of IgG antibody to tetanus toxoid did not differ significantly, and IgG antibodies to diphtheria toxoid were only twofold lower (P = 0.028). Although total IgG, IgM, and IgA levels were higher in two-year-old Apaches than in whites (all P less than 0.001), IgG2 and IgG4 subclasses were lower (both P less than 0.001). Among the Apaches, individual immunoglobulin levels and allotypes were not significantly correlated with their antibody responses to H. influenzae type b polysaccharide.
Conclusions:
Apache children have significant impairment of their antibody response to H. influenzae type b polysaccharide and little or no impairment of their antibody responses to protein toxoids. This immunodeficiency may explain the high incidence of H. influenzae type b infection in this population.