Ly, Ngoc P.Ruiz-Perez, BegonaMcLoughlin, Rachel M.Visness, Cynthia M.Wallace, Paul K.Cruikshank, William W.Tzianabos, Arthur O.O'Connor, George T.Gold, Diane R.Gern, James E.2011-12-292011-12-2920092009-7-8Ly, Ngoc P, Begona Ruiz-Perez, Rachel M McLoughlin, Cynthia M Visness, Paul K Wallace, William W Cruikshank, Arthur O Tzianabos, George T O'Connor, Diane R Gold, James E Gern. "Characterization of regulatory T cells in urban newborns" Clinical and Molecular Allergy 7:8. (2009)1476-7961https://hdl.handle.net/2144/2536BACKGROUND: In the United States, asthma prevalence is particularly high among urban children. Although the underlying immune mechanism contributing to asthma has not been identified, having impaired T regulatory (Treg) cells at birth may be a determining factor in urban children. The objective of this study was to compare Treg phenotype and function in cord blood (CB) of newborns to those in peripheral blood (PB) of a subset of participating mothers. METHODS: 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 naïve (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. RESULTS: 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 naïve (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. CONCLUSION: 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.enCopyright 2009 Ly et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution 2.0 License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.http://creativecommons.org/licenses/by/2.0Article10.1186/1476-7961-7-8195865452717905