An Immunodeficiency Characterized by Impaired Antibody Responses to Polysaccharides

ANTIBODY directed to the capsular polysaccharides of pneumococcus, meningococcus, and Hemophilus influenzae type b is protective against these bacterial pathogens.1 2 3 In most adults the antibody response to polysaccharide antigens predominantly involves the IgG2 subclass.4 5 6 Selective deficiency of this subclass has been associated with recurrent infections,7 although some persons lacking IgG2 antibody do not have an increased susceptibility to infections. An impaired response to polysaccharides has also been observed in ataxia telangiectasia,8 Wiskott–Aldrich syndrome,9 common variable hypogammaglobulinemia,10 and Sjögren's syndrome.11 Except for Wiskott–Aldrich syndrome, these conditions involve either IgG2 deficiency or an impaired response to protein as well as to polysaccharide . . .