title: T-lymphocyte subsets, thymic size and breastfeeding in infancy.
abstract: We followed the changes in concentration of T-lymphocyte subsets (CD4+ and CD8+ cells) in peripheral blood and thymus size during infancy. Previous studies have found increased thymus size in breastfed infants. The present study analyzed the association between breastfeeding and the number of CD4+ and CD8+ cells. Two different populations of infants between birth and 1 year of age were examined. Study Group I: infants with a variable duration of breastfeeding. Study Group II: long-term breastfed infants. In both groups a correlation was found between CD8+ cells and the thymic index at 10 months of age. In Group I, infants still breastfed at the 8-month examination had a higher CD8% than formula-fed infants (p = 0.05), and infants breastfed at the 4-month examination had a higher CD4% at 10 months of age (p= 0.03). Group II showed an increase in the absolute number of CD4+ and CD8+ cells from 8 to 10 months of age; and a positive correlation between the number of breastfeedings per day at 8 months of age, and an increase in CD4+ cells from 8 to 10 months of age (p <0.01). In conclusion, a correlation was found between thymus size and CD8+ cells. Breastfeeding might have both a current and long-term immune-modulating effect on the developing cellular immune system.
authors.affiliation: Department of Pediatrics, Hvidovre Hospital, Copenhagen University, Copenhagen, Denmark. d.jeppesen@dadlnet.dk
authors.forename: Dorthe L
authors.initials: DL
authors.lastname: Jeppesen
authors.forename: Helle
authors.initials: H
authors.lastname: Hasselbalch
authors.forename: Ida M
authors.initials: IM
authors.lastname: Lisse
authors.forename: Annette K
authors.initials: AK
authors.lastname: Ersbøll
authors.forename: Mads D M
authors.initials: MD
authors.lastname: Engelmann
mesh_terms: D001837:Body Weights and Measures; D001942:Breast Feeding; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*