title: Monocyte phenotype and cytokine production profiles are dysregulated by short-duration spaceflight.
abstract: BACKGROUND
  Immune system dysregulation has been demonstrated to occur during and immediately following spaceflight. As the initial bias and magnitude for an immune response is heavily influenced by monocyte/macrophage secreted cytokines, this study investigated monocyte phenotype and cytokine production patterns following short-duration spaceflight.
  
  
  METHODS
  Secreted cytokine profiles were examined by cytometric bead array analysis of culture supernatants following whole blood culture activation with LPS or PMA+ionomycin. Nine short-duration Space Shuttle crewmembers participated in this study.
  
  
  RESULTS
  Peripheral monocyte percentages were unaltered postflight. Constitutive monocyte expression of both CD62L and HLA-DR was reduced following spaceflight in a mission-specific fashion. Loss of either molecule indicates a functional disability of monocytes, either by inhibition of adhesion and tissue migration (CD62L) or by impaired antigen presentation (HLA-DR). Following LPS stimulation of monocytes, postflight expression of IL-6, TNFalpha, and IL-10 were significantly reduced (by 43%, 44%, and 41%, respectively) and expression of IL-1b was elevated (65%). IL-8 production was either elevated or reduced in a mission-specific fashion. Following PMA+ionomycin stimulation of all leukocyte populations, only expression of IL-6 was significantly reduced postflight.
  
  
  CONCLUSIONS
  These data indicate that changes in monocyte constitutive phenotype and inflammatory cytokine production occur following short-duration spaceflight, which may impact overall crewmember immunocompetence. Also, monocyte/macrophage function may be highly sensitive to mission specific parameters.
authors: NASA Johnson Space Center, 2101 NASA Parkway, Mail Code SK, Houston, TX 77058, USA. brian.crucian-1@nasa.gov
authors: Brian
authors: B
authors: Crucian
authors: Raymond
authors: R
authors: Stowe
authors: Heather
authors: H
authors: Quiriarte
authors: Duane
authors: D
authors: Pierson
authors: Clarence
authors: C
authors: Sams
mesh_terms: D005260:Female; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007107:Immune System / Q000276:immunology; D007121:Immunocompetence / Q000276:immunology; D018189:Immunomagnetic Separation; D016130:Immunophenotyping; D019041:L-Selectin / Q000097:blood; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D010641:Phenotype; D013026:Space Flight; D014893:Weightlessness / Q000009:adverse effects*
chemical_list: D019041:L-Selectin