Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

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 ≥1.3 µg/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.

Reduced numbers of switched memory B cells with high terminal differentiation potential in Down syndrome

“…These features already suggested in the 1970s that immunodeficiency is an integral part of the syndrome [14][15][16][17]. Indeed, this has been supported by the findings that the thymus, even in newborns, is small and has an abnormal structure [18], the absolute number of circulating lymphocytes is decreased and antibody responses to vaccine antigens such as oral polio, acellular pertussis, tetanus, hepatitis B, and influenza A are low [19][20][21]. The absolute number of T lymphocytes has been reported to be low at all ages [22] or decreased during the first 2 years of age approaching normal levels thereafter [23].…”

Defective thymic progenitor development and mature T‐cell responses in a mouse model for Down syndrome

“…This loss of function may be consistent with immune dysfunction in DS, as lymphocytes from individuals with DS have also been shown to exhibit a decreased proliferative response to polyclonal stimuli such as phytohaemagglutinin, 47,48 in addition to the documented decrease in responses in some individuals with DS to vaccinations. 49,50 Vaccine studies have shown that IL-7 and TCR signalling can synergize to promote antigen-specific effector cell generation, especially when using subdominant antigens. 51 Therefore decreased IL-7Ra expression as well as the deficient proliferation in response to TCR stimulation may contribute to the T-cell dysfunction observed in DS.…”

Significant impact of recurrent respiratory tract infections in children with Down syndrome

“…Most studies involve development and function of T-lymphocytes (Kusters et al 2009). B-lymphocytopenia and decreased response to unconjugated pneumococcal vaccinations are related to RRTI in non-DS patients and have been described in DS as well (Costa-Carvalho et al 2006;Verstegen et al 2010). The level of impairment of the humoral immune system and its contribution to RRTI in DS has not been fully elucidated; more research on this topic is needed.…”