Abstract
The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 microg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.
Highlights
Down syndrome (DS) is the most common trisomy in liveborn children and the major known genetic cause of mental retardation [1]
We evaluated pneumococcal serotype antibodies before and after immunization with a 23-valent pneumococcal polysaccharide vaccine (Pneumo23®) in DS children
Pneumococcal vaccines have been recommended to groups of patients who are at high risk, or who experience severe or frequent diseases [16]
Summary
Down syndrome (DS) is the most common trisomy in liveborn children and the major known genetic cause of mental retardation [1]. The incidence of DS in Latin American countries is approximately 1/700 live births [2]. Pneumonia and other respiratory diseases are still the major causes of morbidity. Mortality in DS children [3]. Different aspects of the immune system have been studied in DS to obtain a better understanding of the increased risk of infection observed in affected individuals [4]. Abnormalities in humoral and cell-mediated immunities and in phagocytic function have been reported [3,4,5,6,7]
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