title: Quantification of vaccine-induced antipertussis toxin secretory IgA antibodies in breast milk: comparison of different vaccination strategies in women.
abstract: BACKGROUND
  Pertussis vaccination during pregnancy or immediately after delivery is a strategy that is increasingly being recommended to protect young infants from disease. Breast milk contains disease-specific antibodies that can contribute to the protection of young infants. The composition of breast milk could be altered by vaccination during pregnancy or near delivery. However, the quantification of these antibodies in breast milk lacks standardization.
  
  
  METHODS
  In this paper, sample preparation procedures and detection methods for total and antipertussis toxin (anti-PT) secretory immunoglobulin (sIg) A are proposed that can be accurately repeated and are in accordance with European Medicines Agency and Food and Drug Administration requirements. Both antibody analytes were measured in breast milk samples of lactating women obtained 8-9 weeks postpartum to compare different maternal pertussis vaccination strategies: vaccination during pregnancy, shortly after or at delivery (cocoon), less than 5 years before delivery or more than 5 years before delivery.
  
  
  RESULTS
  The validated immunoassays could quantitatively detect total and anti-PT sIgA in the processed breast milk samples. Significantly higher levels of anti-PT sIgA were measured in breast milk after pertussis vaccination during pregnancy or at delivery [geometric mean concentration (GMC): 2.56 and 2.15 IU/mg] in contrast to mothers with no recent (>5 years) pertussis vaccination (GMC: 0.96 IU/mg; P = 0.014 and P = 0.028).
  
  
  CONCLUSIONS
  Vaccination against pertussis in the second/third trimester of pregnancy or immediately postpartum significantly increased the levels of anti-PT sIgA in breast milk.
authors.affiliation: From the *Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, and †Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: De Schutter
authors.forename: Kirsten
authors.initials: K
authors.lastname: Maertens
authors.forename: Lesley
authors.initials: L
authors.lastname: Baerts
authors.forename: Ingrid
authors.initials: I
authors.lastname: De Meester
authors.forename: Pierre
authors.initials: P
authors.lastname: Van Damme
authors.forename: Elke
authors.initials: E
authors.lastname: Leuridan
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007071:Immunoglobulin A, Secretory / Q000032:analysis*; D008895:Milk, Human / Q000737:chemistry* / Q000276:immunology*; D010567:Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000379:methods; D014611:Vaccination / Q000379:methods*
chemical_list: D000907:Antibodies, Bacterial; D007071:Immunoglobulin A, Secretory; D010567:Pertussis Vaccine