INFLUENCE OF AGE ON THE RESPONSE TO STREPTOCOCCUS-PNEUMONIAE VACCINE IN PATIENTS WITH RECURRENT INFECTIONS AND NORMAL IMMUNOGLOBULIN CONCENTRATIONS

Background: A deficient antibody response to polysaccharide antigens i s determined by measuring the response to the 23-valent pneumococcal p olysaccharide vaccine. However, the diagnosis of this specific antibod y deficiency is hampered by the lack of sufficient data and standardiz ed testing of the response to pneumococcal polysaccharides. Methods: A ll patients evaluated in our allergy/immunology clinic for recurrent r espiratory infections between 1995 and 1997 without immunoglobulin, Ig G subclass, or other known primary or secondary immunodeficiency were included in this analysis,IgG antipneumococcal serotypes 1, 3, 4, 6B, 9V, 14, 18C, 19F, and 23F were determined by a modified ELISA protocol . An adequate IgG antibody response to an individual serotype was arbi trarily defined as a postimmunization antibody titer of 1.3 mu g/ml or greater or at least four times the baseline value. Results: A total o f 113 patients fulfilling the criteria for inclusion in this analysis were divided into five age groups. The geometric means for preimmuniza tion and postimmunization pneumococcal antibody titers for all serotyp es increased with age. For postimmunization antibody concentrations, t here was a sharp increase in the specific antibody concentrations in a dults in comparison with all pediatric age groups ranging in age from 7 months to 16 years. Similarly, the number of serotypes to which ther e was an adequate response also increased with age. Conclusion: We con clude that the definition of what constitutes an adequate response to pneumococcal immunization needs further definition. It is clear, howev er, that age has an important influence on the intensity of the respon se to most pneumococcal polysaccharides. Correlation studies between a ntibody concentrations in different IgG subclasses, functional studies , and protection studies against mucosal and invasive pneumococcal inf ections are in progress, and these should contribute to a refined defi nition of a normal response. The availability of a standardized method for the measurement of IgG antibodies against relevant pneumococcal s erotypes is an important step toward this goal.