title: Generation of switched memory B cells in response to vaccination in Down syndrome children and their siblings.
abstract: BACKGROUND
  Immunodeficiency is an integral aspect of Down syndrome, as demonstrated by the increased susceptibility to infection of affected. Mortality is still higher than in general population, with respiratory infections among the major causes of death. As more people with Down syndrome are living today than ever before, it is indispensable to develop strategies to prevent and cure the associated disorders. Vaccination is the most successful instrument of preventive medicine. Special seasonal influenza and pneumococcal vaccination strategies have been designed for individuals with risk conditions of all ages. Down syndrome individuals are not included in the high-risk categories.
  
  
  METHODS
  We enrolled in our study 15 children with Down syndrome and their siblings, vaccinated for the first time with seasonal influenza vaccine and receiving a booster dose of a glyco-conjugated pneumococcal vaccine. We compared the immunological features and response to vaccination measuring serum antibody titers and frequency of specific memory B cells.
  
  
  RESULTS
  We confirm that a severe reduction of switched memory B cells is always associated to Down syndrome. After primary vaccination Down syndrome children generate significantly less specific switched memory B cells than their siblings. The response to a booster dose of vaccine is instead comparable in both groups. The production of specific antibodies was equally effective in Down syndrome and controls both after primary and secondary immunization.
  
  
  CONCLUSIONS
  Down syndrome individuals should be considered a high risk group, because of their increased susceptibility to infection and reduced number of switched memory B cells. Tailored vaccination protocols are needed in order to reduce their burden of infections throughout life.
authors.affiliation: Pediatric and Infectious Disease Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Diletta
authors.initials: D
authors.lastname: Valentini
authors.affiliation: Immunology Unit, Immunology and Pharmacotherapy Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Marcellini
authors.affiliation: Pediatric and Infectious Disease Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Bianchi
authors.affiliation: Pediatric and Infectious Disease Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Villani
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Marzia
authors.initials: M
authors.lastname: Facchini
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Donatelli
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Maria Rita
authors.initials: MR
authors.lastname: Castrucci
authors.affiliation: Immunology Unit, Immunology and Pharmacotherapy Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Marasco
authors.affiliation: Immunology Unit, Immunology and Pharmacotherapy Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Farroni
authors.affiliation: Immunology Unit, Immunology and Pharmacotherapy Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Diagnostic Immunology Unit, Department of Oncohematology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. Electronic address: rita.carsetti@opbg.net.
authors.forename: Rita
authors.initials: R
authors.lastname: Carsetti
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000276:immunology*; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008297:Male; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D035781:Siblings
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D022242:Pneumococcal Vaccines
keywords: Antibodies; Down syndrome; Respiratory infections; Switched memory B cells; Vaccination