Characterization of regulatory T cells in urban newborns

Treg numbers, expression, and suppressive function were quantified in subjects recruited prenatally from neighborhoods where ≥ 20% of families have incomes below the poverty line. Proportion of Treg cells and expression of na？ve (CD45RA) or activated (CD45RO, CD69, and HLA-DR) markers in CD4+T cells was measured by flow cytometry. Treg suppressive capacity was determined by quantifying PHA-stimulated lymphocyte proliferation in mononuclear cell samples with and without CD25 depletion.In an urban cohort of 119 newborns and 82 mothers, we found that newborns had similar number of cells expressing FOXP3 as compared to the mothers but had reduced numbers of CD4+CD25+bright cells that predominantly expressed the na？ve (CD45RA) rather than the activated/memory (CD45RO) phenotype found in the mothers. Additionally, the newborns had reduced mononuclear cell TGF-β production, and reduced Treg suppression of PHA-stimulated lymphocyte proliferation compared to the mothers.U.S. urban newborns have Treg cells that express FOXP3, albeit with an immature phenotype and function as compared to the mothers. Longitudinal follow-up is needed to delineate Treg cell maturation and subsequent risk for atopic diseases in this urban birth cohort.The ability of CD4+CD25+ T regulatory (Treg) cell to down-regulate immune responses associated with asthma in experimental animal models [1-4] has recently ignited interest in defining the role of Treg cells in allergy and asthma in humans. Most studies on the association between Treg and asthma/allergy have focused on adults [5-8] with allergy or on children [9] with established asthma. Since a majority of cases of asthma are diagnosed in early childhood, [10,11] characterizing Treg phenotype and function in at-risk children prior to the clinical manifestation of asthma may provide a more cohesive understanding of Treg ontogeny and the impact dysregulated Treg have on the development of asthma. Recently, two studies have suggested that Treg functio