Influenza A/H1N1 Vaccination Response Is Inadequate in Down Syndrome Children When the Latest Cut-off Values Are Used
ABSTRACT We determined the response of 48 Down syndrome (DS) children to 2 doses of influenza A/H1N1 vaccination. 92% reached the previously defined protective level (HI titer ≥1:40), but only 27% reached the level of ≥1:110 which was recently described to predict the conventional 50% clinical protection rate in children. Further studies, and potentially adaptations of the schedule, are needed.
SourceAvailable from: Andrea Bartuli[Show abstract] [Hide abstract]
ABSTRACT: Children with Down syndrome have increased susceptibility to infections and a high frequency of leukemia and autoimmune disorders, suggesting that immunodeficiency and immune dysfunction are integral parts of the syndrome. A reduction in B-cell numbers has been reported, associated with moderate immunodeficiency and normal immunoglobulin levels. Here we compared B-cell populations of 19 children with Down syndrome with those in healthy age-matched controls. We found that all steps of peripheral B-cell development are altered in Down syndrome, with a more severe defect during the later stages of B-cell development. Transitional and mature-naïve B-cell numbers are reduced by 50% whereas switched memory B cells represent 10-15% of the numbers in age-matched controls. Serum IgM levels were slightly reduced, but all other immunoglobulin isotypes were in the normal range. The frequency of switched memory B cells specific for vaccine antigens was significantly lower in affected children than in their equivalently vaccinated siblings. In vitro switched memory B cells of patients with Down syndrome have an increased ability to differentiate into antibody-forming cells in response to TLR9 signals. Tailored vaccination schedules increasing the number of switched memory B cells may improve protection and reduce the risk of death from infection in Down syndrome. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.European Journal of Immunology 03/2015; 45(3). DOI:10.1002/eji.201445049 · 4.52 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: We investigated the anti-polysaccharide antibody responses in subjects with Down syndrome (DS) because DS subjects show decreased peripheral B-lymphocyte numbers in all age groups, and a clinical picture of recurrent respiratory tract infections and increased incidence of autoimmune diseases which is reminiscent of common variable immunodeficiency disorders (CVID)-like disease. We determined titers and opsonophagocytosis in response to conjugated and unconjugated pneumococcal serotypes in 18 DS subjects aged 6-24 years. The results show adequate serotype-specific antibody titers in response to all conjugated and almost all unconjugated serotypes used. Opsonophagocytosis activity as measured against pneumococcal serotypes 9N, 19F and 23F was also found to be intact. We conclude that DS subjects do not have a clear defect in their anti-polysaccharide antibody response.Vaccine 11/2013; DOI:10.1016/j.vaccine.2013.09.070 · 3.49 Impact Factor