title: Alterations in regulatory T cell subpopulations seen in preterm infants.
abstract: Regulatory T cells are a population of CD4+ T cells that play a critical role in peripheral tolerance and control of immune responses to pathogens. The purpose of this study was to measure the percentages of two different regulatory T cells subpopulations, identified by the presence or absence of CD31 (Recent thymic emigrants and peripherally induced naïve regulatory T cells), in term and preterm infant cord blood. We report the association of prenatal factors, intrauterine exposure to lipopolysaccharide and inflammation and the percentages of these regulatory T cell subpopulations in term and preterm infants. Cord blood samples were collected from both term and preterm infants and mononuclear cells isolated over a Ficoll-Hypaque cushion. Cells were then stained with fluorochrome-labeled antibodies to characterize regulatory T cell populations and analyzed with multi-color flow cytometry. Cord blood plasma C-reactive protein, and lipopolysaccharide were also measured. Placental pathology was also examined. We report a gestational age-dependent difference in the percentage of total regulatory T cells, in which preterm infants of lower gestational ages have an increased percentage of regulatory T cells. We report the presence of two populations of regulatory T cells (CD31+ and CD31-) in cord blood of term and preterm infants and their association with different maternal and fetal characteristics. Factors associated with differences in the percentage of CD31- Tregs included the use of prenatal antibiotics, steroids and magnesium sulfate. In addition, the percentage of CD31- Tregs was significantly higher in cord blood of preterm pregnancies associated with inflammation and prenatal lipopolysaccharide exposure. The peripheral Treg pool of preterm infants could be altered by prenatal exposure to inflammation and chorioamnionitis; however, the clinical implications of this finding are not yet understood.
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of South Florida, Morsani College of Medicine, Tampa, Florida, United States of America.
authors.forename: Angel A
authors.initials: AA
authors.lastname: Luciano
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of South Florida, Morsani College of Medicine, Tampa, Florida, United States of America.
authors.forename: Ileana M
authors.initials: IM
authors.lastname: Arbona-Ramirez
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of South Florida, Morsani College of Medicine, Tampa, Florida, United States of America.
authors.forename: Rene
authors.initials: R
authors.lastname: Ruiz
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of South Florida, Morsani College of Medicine, Tampa, Florida, United States of America.
authors.forename: Braulio J
authors.initials: BJ
authors.lastname: Llorens-Bonilla
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of South Florida, Morsani College of Medicine, Tampa, Florida, United States of America.
authors.forename: Denise G
authors.initials: DG
authors.lastname: Martinez-Lopez
authors.affiliation: Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Funderburg
authors.affiliation: Department of Pediatrics, Division of Allergy, Immunology and Bone Marrow Transplant, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Morna J
authors.initials: MJ
authors.lastname: Dorsey
mesh_terms: D000328:Adult; D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000276:immunology; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects; D008297:Male; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000276:immunology* / Q000378:metabolism; D047928:Premature Birth / Q000097:blood / Q000139:chemically induced / Q000276:immunology*; D013256:Steroids / Q000008:administration & dosage / Q000009:adverse effects; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: D000700:Analgesics; D000900:Anti-Bacterial Agents; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D013256:Steroids; D008278:Magnesium Sulfate