title: Neutrophils are immune cells preferentially targeted by retinoic acid in elderly subjects.
abstract: BACKGROUND
  The immune system gradually deteriorates with age and nutritional status is a major factor in immunosenescence. Of the many nutritional factors implicated in age-related immune dysfunction, vitamin A may be a good candidate, since vitamin A concentrations classically decrease during aging whereas it may possess important immunomodulatory properties via its active metabolites, the retinoic acids. This prompted us to investigate the immune response induced by retinoids in adults and elderly healthy subjects. Before and after oral supplementation with 13cis retinoic acid (0.5 mg/kg/day during 28 days), whole blood cells were phenotyped, and functions of peripheral blood mononuclear cells (PBMC) and polymorphonuclear cells (PMN) were investigated by flow cytometry and ELISA tests.
  
  
  RESULTS
  In both young adults (n = 20, 25 ± 4 years) and older subjects (n = 20, 65 ± 4 years), retinoic acid supplementation had no effect on the distribution of leukocyte subpopulations or on the functions of PBMC (Il-2 and sIl-2R production, membrane expression of CD25). Concerning PMN, retinoic acid induced an increase in both spontaneous migration and cell surface expression of CD11b in the two different age populations, whereas bactericidal activity and phagocytosis remained unchanged.
  
  
  CONCLUSIONS
  We demonstrated that retinoic acid induces the same intensity of immune response between adult and older subjects, and more specifically affects PMN functions, i.e. adhesion and migration, than PBMC functions.
authors: Clermont University, Université d'Auvergne, EA4233, LB2MN, CRNH-A, BP10448, F-63000 Clermont-Ferrand, France. regine.minet-quinard@u-clermont1.fr.
authors: Régine
authors: R
authors: Minet-Quinard
authors: M Chantal
authors: MC
authors: Farges
authors: Emilie
authors: E
authors: Thivat
authors: Cécile
authors: C
authors: Deleine
authors: Gilles
authors: G
authors: Mayot
authors: Julius
authors: J
authors: Brtko
authors: Josep
authors: J
authors: Ribalta
authors: Brigitte
authors: B
authors: Winklhofer-Roob
authors: Edmond
authors: E
authors: Rock
authors: M Paule
authors: MP
authors: Vasson