IgG antibody response to polysaccharides in children with recurrent infections.

IgG2 subclass deficiency associated with poor antibody response to polysaccharide antigen is a now well-described entity. A newer entity which appears to be at least as common is the recurrent infection with a selective deficiency in the antibody response. At the present time, the antibody response to Haemophilus influenzae type b (Hib) is a good marker for the selective antibody deficiency in these children, as the vast majority of such children made a very poor antibody response to Hib. The data suggest that treatment of these children with prophylactic antibiotics and/or with IV gamma-globulin, depending on the clinical situation, is beneficial. This reinforces the view that the observed abnormality in the antibody response may be causally related to the recurrent infections. Prospective studies of the 10% of 'normal' children who fail to respond to soluble polysaccharide antigen would reveal if there is within this group a higher incidence of recurrent infections. The result of such studies will be important in our understanding of normal as well as abnormal selective antigen-specific antibody deficiencies in children.