title: Temporal biological variability in dendritic cells and regulatory T cells in peripheral blood of healthy adults.
abstract: BACKGROUND
  Studies evaluating circulating dendritic cells (DCs) and natural and induced regulatory T cells (nTregs, iTregs) are often obtained at a single time point and difficult to interpret without understanding their intrinsic day-to-day biologic variability.
  
  
  METHODS
  We investigated the day-to-day variability in quantifying DCs, nTregs (FoxP3(+)CD25(+)CD4(+)) and cytokine production by iTregs (granzyme B-GZB, Th1/2 cytokines following CD3 plus CD46 in vitro activation) from peripheral blood mononuclear cells (PBMCs) collected on three consecutive days in healthy adults. Intraclass correlation coefficients (ICCs) were used to evaluate intra-individual variability.
  
  
  RESULTS
  In 10 healthy adults, the %PBMCs of plasmacytoid (pDC) and myeloid (mDC1 and mDC2) were 0.27 ± 0.12, 0.22 ± 0.10, and 0.02 ± 0.02, with ICC 0.91, 0.90, and 0.17 respectively. Natural Tregs (3.27 ± 1.27% CD4(+) cells) had an ICC of 0.86. Inducible Tregs (GZB-positive, 35.3 ± 17.7% CD4(+) cells) had an ICC of 0.77. The ICCs for IL-10, TNF-α, IFN-γ, IL-4, and IL-5 production by iTregs were 0.49, 0.63, 0.68, 0.74, and 0.82, respectively. There were no significant changes in ICC (<0.1) after adjusting for age, gender and atopy except for IL-4. Substantial variability for iTregs was determined for the control condition (PBS with IL-2).
  
  
  CONCLUSIONS
  No meaningful day-to-day biologic variability was observed for the quantification of nTregs, pDC and mDC1 in normal adults; however, there was substantial variability in measuring mDC2 proportions and iTreg production of IL-10. These results suggest obtaining an average of several measurements over time to determine the most representative value of these biologic measures.
authors: Division of Allergy, Immunology and Pulmonary Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, United States.
authors: Maleewan
authors: M
authors: Kitcharoensakkul
authors: Division of Allergy, Immunology and Pulmonary Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, United States.
authors: Leonard B
authors: LB
authors: Bacharier
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, United States.
authors: Huiqing
authors: H
authors: Yin-Declue
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, United States.
authors: Jonathan S
authors: JS
authors: Boomer
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, United States.
authors: Dana
authors: D
authors: Burgdorf
authors: Division of Biostatistics, Washington University School of Medicine, United States.
authors: Brad
authors: B
authors: Wilson
authors: Division of Biostatistics, Washington University School of Medicine, United States.
authors: Kenneth
authors: K
authors: Schechtman
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, United States. Electronic address: castrom@dom.wustl.edu.
authors: Mario
authors: M
authors: Castro
mesh_terms: D000328:Adult; D001772:Blood Cell Count; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D006262:Health; D064368:Healthy Volunteers; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology*; D008297:Male; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D013997:Time Factors
chemical_list: D016207:Cytokines
keywords: Dendritic cells; Human; Regulatory T cells; Variability