title: Retinol concentrations after birth are inversely associated with atopic manifestations in children and young adults.
abstract: BACKGROUND
  Vitamin A has anti-inflammatory and immunomodulatory effects, and its deficiency results in impaired specific and innate immunity. Vitamin A is essential for inducing the gut-homing specificity on T cells.
  
  
  OBJECTIVE
  As an impaired gut immune response in early infancy may contribute to the development of atopic sensitization, we looked for an association of plasma retinol concentrations and the subsequent development of allergic symptoms in healthy infants.
  
  
  METHODS
  A cohort of 200 unselected, full-term newborns were followed up from birth to age 20 years. The plasma retinol concentration was determined in cord blood (n=97), at ages of 2, 4 and 12 months (n=95), and at ages 5 years (n=155) and 11 years (n=151). The subjects were re-examined at the ages of 5, 11 and 20 years with assessment of the occurrence of allergic symptoms during the preceding year, skin prick testing and measurement of serum total IgE.
  
  
  RESULTS
  subjects with allergic symptoms or a positive skin prick test (SPT) in childhood or adolescence had lower retinol concentrations in infancy and childhood than symptom-free subjects. The difference was most pronounced at age 2 months. Retinol concentration at 2 months correlated inversely with positive SPT at ages of 5 and 20 years, and with allergic symptoms at age 20 years.
  
  
  CONCLUSIONS
  Retinol concentration in young infants is inversely associated with the subsequent development of allergic symptoms. We propose that an inborn regulation of retinol may play a role in atopic sensitization, possibly through regulating the intestinal T cell responses.
authors.affiliation: Department of Dermatology, The Skin and Allergy Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland. maria.pesonen@luukku.com
authors.forename: M
authors.initials: M
authors.lastname: Pesonen
authors.forename: M J T
authors.initials: MJ
authors.lastname: Kallio
authors.forename: M A
authors.initials: MA
authors.lastname: Siimes
authors.forename: A
authors.initials: A
authors.lastname: Ranki
mesh_terms: D016022:Case-Control Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006967:Hypersensitivity / Q000097:blood* / Q000175:diagnosis / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D007231:Infant, Newborn; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D012737:Sex Factors; D012882:Skin Tests; D014801:Vitamin A / Q000097:blood*
chemical_list: D014801:Vitamin A; D007073:Immunoglobulin E