Clinical correlates of response to pneumococcal immunization

Objective: The inability to form antibodies to polysaccharide antigens may occur as a part of a more significant immunodeficiency or as an isolated defect. The latter has been reported in some children with recurrent upper and lower respiratory tract infections and evaluation of the responsiveness of such patients to polysaccharide antigens is indicated as part of their assessment. The present study evaluated the pattern of antibody responses of patients immunized with pneumococcal vaccine as part of the investigation of recurrent upper and lower respiratory tract infections to determine if any correlation exists between these responses and clinical presentation. Methodology: An analysis was performed of antibody responses to pneumococcal serotypes 3, 4 and 6 following immunization with a 23-valent vaccine in 42 children with normal IgG levels who were evaluated for recurrent infections. Antibody responses were assessed in relation to clinical features and the results of other immunological investigations. Results: Of the 42 patients evaluated, 25 (59%) were responders to all serotypes tested. Failure to respond to serotype 3 alone was the least common pattern of non-response. Recurrent pneumonia, but not otitis media with discharge or chronic productive cough, was significantly associated with a lack of response to two or three serotypes. Failure to respond to serotype 3 alone or in combination with other serotypes was associated with more significant immune abnormalities. Conclusion: In a selected population of children with recurrent bacterial infections, pneumococcal serotype 3 is a strong immunogen. In this clinical group recurrent pneumonia is associated with a defect in response to multiple pneumococcal serotypes.