title: Decreased memory B cells and increased CD8 memory T cells in blood of breastfed children: the generation R study.
abstract: BACKGROUND
  Breastfeeding provides a protective effect against infectious diseases in infancy. Still, immunological evidence for enhanced adaptive immunity in breastfed children remains inconclusive.
  
  
  OBJECTIVE
  To determine whether breastfeeding affects B- and T-cell memory in the first years of life.
  
  
  METHODS
  We performed immunophenotypic analysis on blood samples within a population-based prospective cohort study. Participants included children at 6 months (n=258), 14 months (n=166), 25 months (n=112) and 6 years of age (n=332) with both data on breastfeeding and blood lymphocytes. Total B- and T-cell numbers and their memory subsets were determined with 6-color flow cytometry. Mothers completed questionnaires on breastfeeding when their children were aged 2, 6, and 12 months. Multiple linear regression models with adjustments for potential confounders were performed.
  
  
  RESULTS
  Per month continuation of breastfeeding, a 3% (95% CI -6, -1) decrease in CD27+IgM+, a 2% (95 CI % -5, -1) decrease in CD27+IgA+ and a 2% (95% CI -4, -1) decrease in CD27-IgG+ memory B cell numbers were observed at 6 months of age. CD8 T-cell numbers at 6 months of age were 20% (95% CI 3, 37) higher in breastfed than in non-breastfed infants. This was mainly found for central memory CD8 T cells and associated with exposure to breast milk, rather than duration. The same trend was observed at 14 months, but associations disappeared at older ages.
  
  
  CONCLUSIONS
  Longer breastfeeding is associated with increased CD8 T-cell memory, but not B-cell memory numbers in the first 6 months of life. This transient skewing towards T cell memory might contribute to the protective effect against infectious diseases in infancy.
authors.affiliation: The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Department of Pediatrics, Sophia Children's Hospital, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Michelle A E
authors.initials: MA
authors.lastname: Jansen
authors.affiliation: The Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Diana
authors.initials: D
authors.lastname: van den Heuvel
authors.affiliation: The Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Menno C
authors.initials: MC
authors.lastname: van Zelm
authors.affiliation: The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Department of Pediatrics, Sophia Children's Hospital, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.affiliation: The Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.affiliation: The Department of Pediatrics, Sophia Children's Hospital, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
authors.affiliation: The Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Herbert
authors.initials: H
authors.lastname: Hooijkaas
authors.affiliation: The Department of Pediatrics, Sophia Children's Hospital, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
authors.forename: Henriette A
authors.initials: HA
authors.lastname: Moll
mesh_terms: D000328:Adult; D000367:Age Factors; D016175:B-Lymphocyte Subsets / Q000145:classification / Q000276:immunology*; D001942:Breast Feeding; D018414:CD8-Positive T-Lymphocytes / Q000145:classification / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D007223:Infant; D016014:Linear Models; D008297:Male; D008895:Milk, Human / Q000166:cytology* / Q000276:immunology*; D018448:Models, Immunological; D011247:Pregnancy; D011446:Prospective Studies; D016176:T-Lymphocyte Subsets / Q000145:classification / Q000276:immunology