Impaired antibody response to pneumococcal capsular polysaccharides and phosphorylcholine in adult patients with a history of bacteremic pneumococcal infection.

The serum antibody response after immunization with a pneumococcal vaccine was analyzed in 46 patients with a history of bacteremic pneumococcal infection and in 36 healthy controls. Seven patients with IgG/IgG2 deficiencies had significantly lower preimmunization and postimmunization levels of antibody to pneumococcal capsular polysaccharides (serotypes 3, 6A, 19F, and 23F) and phosphorylcholine than did the control subjects, while the patients with normal IgG/IgG2 levels did not have a deficient antibody response. For the whole patient group, postimmunization levels of antibody against the serotypes that caused the bacteremias were lower than the levels against other tested serotypes (P < .05). Ten patients vs. one control subject were unable to mount a postimmunization antibody response to the four tested serotypes (P < .05). Six of these 10 nonresponding patients had low IgG/IgG2 levels. The results demonstrate that a poor antibody response to vaccination with capsular polysaccharides, often associated with IgG/IgG2 deficiency, is common in patients with a history of bacteremic pneumococcal infections.