RESPONSE TO PNEUMOCOCCAL IMMUNIZATION IN CHILDREN WITH AND WITHOUT RECURRENT INFECTIONS

Many children with recurrent sinopulmonary infections fail to mount an adequate humoral response following immunization with polysaccharide antigens. At present there are no controlled studies comparing respons es to pneumococcal immunization in children with recurrent infections and a healthy, age-matched cohort. Immunological evaluation was perfor med on 66 children with recurrent sinopulmonary infections, aged 2-5 y ears (mean 3.06 +/- 0.92). A control group included 28 healthy, age-ma tched controls (mean 3.14 +/- 0.88 years). Both groups were immunized with 23 valent pneumococcal vaccine, and titers were measured before a nd 4 weeks after immunization. Antibody levels to 12 pneumococcal sero types were measured via radioimmunoassay. Geometric preimmunization me an titers in the control group were 215.5 +/- 157 ngAbN/ml rising to 9 89.5 +/- 745 ngAbN/ml compared to 77.71 +/- 38.4 ngAbN/ml increasing t o 446.7 +/- 406 ngAbN/ml in the study group (p < .05). Serotypes 3, 4, 7F, 8, 9N, and 18C were the most immunogenic, while serotypes 6A and 14 were the least. Overall, the control group responded to 7.71 +/- 1. 24 serotypes versus 5.1 +/- 2.0 in the study group (p < .05), where po stimmunization titers at least doubled and rose to greater than or equ al to 300 ngAbN/ml. All controls responded to at least five or more se rotypes, 26/28 responded to 6 or more. In contrast, only 38/66 (57%) o f study patients responded to five or more serotypes, and only 27/66 ( 41%) responded to at least 6 of 12. Preimmunization titers of greater than 300 ngAbN/ml were present in 30% (102/336) of the control serotyp es; however, only 53 of these (52%) doubled post immunization; 22% of the elevated titers decreased post immunization. Markedly elevated tit ers greater than or equal to 500 ngAbN/ml were present in 20% (69/336) of the preimmunization serotypes, only 39% of these doubled post immu nization. Twenty-three valent pneumococcal vaccine is immunogenic in y oung, healthy children. A significant percentage of children with recu rrent sinopulmonary infections fail to produce adequate serotype speci fic antibodies following pneumococcal immunization.