Impaired antibody response to Haemophilus influenzae type b polysaccharide and low IgG2 and IgG4 concentrations in Apache children.
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.
Siber
G R
GR
Laboratory of Infectious Diseases, Dana-Farber Cancer Institute, Boston, MA 02115.
Santosham
M
M
Reid
G R
GR
Thompson
C
C
Almeido-Hill
J
J
Morell
A
A
deLange
G
G
Ketcham
J K
JK
Callahan
E H
EH
D000907:Antibodies, Bacterial / Q000032:analysis; D000917:Antibody Formation; D016667:Bacterial Capsules; D001428:Bacterial Vaccines / Q000276:immunology*; D002675:Child, Preschool; D004168:Diphtheria Toxoid / Q000276:immunology; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007126:Immunoglobulin Allotypes / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis; D007198:Indians, North American; D007223:Infant; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D007070:Immunoglobulin A; D007126:Immunoglobulin Allotypes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011135:Polysaccharides, Bacterial; D013745:Tetanus Toxoid