title: Phenotypic differences between cord blood and adult peripheral blood.
abstract: OBJECTIVE
  Neonates are more susceptible to infections than adults, due to a less mature immune system. The objective of this study was to compare the immunophenotypes of cord blood (CB) and adult peripheral blood (APB) and to establish whether or not there are immunophenotypical differences.
  
  
  METHODS
  CB and APB were collected into CPD anticoagulant. Whole blood was stained with fluorochrome conjugated antibodies, cells were fixed, red cells were lysed, and samples were run in a FACSCanto flow cytometer.
  
  
  RESULTS
  Plots of SSC vs. CD45 showed two lymphocyte-like populations in CB with the same low SSC characteristics while there was only one low SSC lymphoid population in APB. The CD45dim population included the majority of CD34+ cells, but it also included T, B, NKT, and NK cells. The percentages of CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD3+CD56+, and CD3-CD56+ in the CD45high gate of CB were similar to the percentages obtained for APB. Meanwhile, in the CD45dim gate, the percentages were either lower (CD3+, CD3+CD4+, CD3+CD8+) or higher (CD19+, CD3+CD56+, CD3-CD56+) than in the CD45high gate.
  
  
  CONCLUSIONS
  CB presents two lymphoid populations defined by different levels of expression of the phosphatase CD45; the CD45dim subsets likely represent cells with elevated proliferative activity possibly due to the differential expression of CD45 but still not yet immunologically mature with regard to immunophenotype and function.
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA. mcl05@health.state.ny.us
authors.forename: María C
authors.initials: MC
authors.lastname: López
authors.forename: Brent E
authors.initials: BE
authors.lastname: Palmer
authors.forename: David A
authors.initials: DA
authors.lastname: Lawrence
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D053450:Glucocorticoid-Induced TNFR-Related Protein / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D010641:Phenotype; D013601:T-Lymphocytes / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D015415:Biomarkers; D053450:Glucocorticoid-Induced TNFR-Related Protein; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C491405:TNFRSF18 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human