NASOPHARYNGEAL ANTIBODIES TO PNEUMOCOCCAL CAPSULAR POLYSACCHARIDES INCHILDREN WITH ACUTE OTITIS-MEDIA

Antibodies to pneumococcal capsular polysaccharides were measured by E IA in acute- and convalescent-phase nasopharyngeal aspirates from 120 children with acute otitis media. Nasopharyngeal IgM- and IgG-class an tibodies were rare, whereas IgA was detected more often, occurred inde pendently from serum IgA, and correlated with the presence of the secr etory component in pneumococcal antibody, indicating local production of IgA. Thirty-four percent of the children with pneumococci in middle ear fluid developed a nasopharyngeal IgA response to the polysacchari de pool of serotypes 6B, 14, 19F, and 23F compared with 7% of the chil dren with pneumococci only in the nasopharynx or not found at all (P = .004). The responses were observed in children of all ages, the young est 6 months of age. This supports the hypothesis that mucosal immunit y to bacterial polysaccharides matures earlier than systemic immunity.