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.

Down Syndrome B-Lymphocyte Subpopulations, Intrinsic Defect or Decreased T-Lymphocyte Help

“…The latter has indeed been described (3,15). However, the T-cell-independent antibody response to pneumococcal polysaccharide antigen is also decreased in DS (4), suggesting an intrinsic B-lymphocyte defect is also present. We studied B-lymphocyte subpopulations in relation to relevant clinical features in 95 children with DS, to further unravel this question.…”

“…respiratory-infections (1,2), decreased responses to vaccination (3)(4)(5)(6)(7)(8), a higher frequency of hepatitis B surface antigen carriers (3), and autoimmune diseases such as celiac disease and hypothyroidism (9 -11). These features are suggestive of immunodeficiency.…”

“…Deficient T-lymphocyte help could lead to disturbed B-lymphocyte activation and proliferation. Despite the B lymphocytopenia, a considerable hypergammaglobulinemia of IgA and IgG after the age of 5 y, with high levels of IgG 1 and IgG 3 and low levels of IgG 2 and IgG 4 , is described (3,15,16).…”

What people with Down Syndrome can teach us about cardiopulmonary disease

“…Both intrinsic immune defects and extrinsic (anatomical) factors contribute to disturbed immune function and respiratory infection in individuals with Down syndrome [166][167][168]. Reduced numbers of T-and B-lymphocytes and abnormalities of their function both undoubtedly contribute to altered immunoglobulin levels, poor responses to vaccinations and increased respiratory infections [36,166,169,170]. In Down syndrome, the effects of an altered immune system on CHD or CAD are unknown.…”

“…In one study of 26 children with Down syndrome, only one individual had decreased IgG2 levels, yet 18 out of 26 had increased rates of infection [175,176]. Following vaccination to influenza A or polysaccharide pneumococcus, antibody responses are active in persons with Down syndrome, yet antibody titres are lower [166,169,177,178]. One possible contribution to increased prevalence and severity of pulmonary infection in Down syndrome could be reduced numbers of subsets of B-cells, such as switched memory B-cells [179,180].…”