title: Hematopoietic progenitors and aging: alterations in granulocytic precursors and responsiveness to recombinant human G-CSF, GM-CSF, and IL-3.
abstract: BACKGROUND
  Changes either in the number or in the responsiveness of hematopoietic progenitors may be a major factor accounting for age-related changes in stimulus driven hematopoiesis.
  
  
  METHODS
  To test these hypotheses, we compared the relative proportions and the responsiveness of CD34+ bone marrow cells from healthy young (20-30 yrs) and healthy elderly (70-80 yrs) volunteers to G-CSF, GM-CSF, and IL-3 in an in vitro marrow culture system.
  
  
  RESULTS
  There was no age-related difference either in the proportion of CD34+ marrow cells or in the proportion of a more mature CD34+ subset, defined as CD34+, CD33+ cells. Maximal colony formation by CD34+ cells stimulated with a combination of G-CSF, GM-CSF, and IL-3 was similar in the two groups, but the dose-response studies with individual growth factors revealed a 2-fold decrease in sensitivity of the elderly subjects' cells to G-CSF (p < .01).
  
  
  CONCLUSIONS
  Aging has little impact on the marrow content of early precursors of the neutrophil lineage. There is, however, a significant difference in the in vitro proliferative response of these cells to the lineage specific growth factor G-CSF. This alteration may account for the greater propensity in elderly populations for the development of neutropenia with severe infections and chemotherapy.
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle.
authors.forename: G S
authors.initials: GS
authors.lastname: Chatta
authors.forename: R G
authors.initials: RG
authors.lastname: Andrews
authors.forename: E
authors.initials: E
authors.lastname: Rodger
authors.forename: M
authors.initials: M
authors.lastname: Schrag
authors.forename: W P
authors.initials: WP
authors.lastname: Hammond
authors.forename: D C
authors.initials: DC
authors.lastname: Dale
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015703:Antigens, CD / Q000032:analysis; D001854:Bone Marrow Cells; D002455:Cell Division; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage / Q000502:physiology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D007377:Interleukin-3 / Q000008:administration & dosage / Q000502:physiology*; D008297:Male
chemical_list: D015703:Antigens, CD; D007377:Interleukin-3; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor