Development of anti-polysaccharide antibodies in asplenic children.

Splenectomized patients are highly susceptible to infections with capsulated bacteria and an impaired response to vaccination with bacterial polysaccharides has frequently been observed in these individuals. Based partly on experimental animal data, an important role for the spleen in the production of specific anti-carbohydrate antibodies, i.e. mostly IgG2 in normal adults, has been suggested. We therefore determined the immunoglobulin class and subclass pattern of serum antibodies from asplenic patients against protein and carbohydrate antigens. Normal levels of total serum IgM, IgG2 and specific IgM and IgG2 anti-polysaccharide antibodies were observed, suggesting only a minor role for the spleen in determining the antibody repertoire. The data imply that the impaired phagocytic capacity and/or the inability to mount a sufficiently rapid antibody response are the main factors underlying the increased susceptibility to bacterial infections noted in these patients.