title: Immune system dysregulation occurs during short duration spaceflight on board the space shuttle.
abstract: BACKGROUND
  Post-flight data suggests immunity is dysregulated immediately following spaceflight, however this data may be influenced by the stress effects of high-G entry and readaptation to terrestrial gravity. It is unknown if immunity is altered during spaceflight.
  
  
  METHODS
  Blood samples were collected from 19 US Astronauts onboard the Space Shuttle ~24 h prior to landing and returned for terrestrial analysis. Assays consisted of leukocyte distribution, T cell blastogenesis and cytokine production profiles.
  
  
  RESULTS
  Most bulk leukocyte subsets (WBC, differential, lymphocyte subsets) were unaltered during spaceflight, but were altered following landing. CD8+ T cell subsets, including cytotoxic, central memory and senescent were altered during spaceflight. T cell early blastogenesis varied by culture mitogen. Functional responses to staphylococcal enterotoxin were reduced during and following spaceflight, whereas response to anti-CD3/28 antibodies was elevated post-flight. The level of virus specific T cells were generally unaltered, however virus specific T cell function was depressed both during and following flight. Plasma levels of IFNα, IFNγ, IL-1β, IL-4, IL-10, IL-12, and TNFα were significantly elevated in-flight, while IL-6 was significantly elevated at R + 0. Cytokine production profiles following mitogenic stimulation were significantly altered both during, and following spaceflight. Specifically, production of IFNγ, IL-17 and IL-10 were reduced, but production of TNFα and IL-8 were elevated during spaceflight.
  
  
  CONCLUSIONS
  This study indicates that specific parameters among leukocyte distribution, T cell function and cytokine production profiles are altered during flight. These findings distinguish in-flight dysregulation from stress-related alterations observed immediately following landing.
authors.affiliation: NASA Johnson Space Center, Houston, TX 77058, USA. brian.crucian-1@nasa.gov
authors.forename: Brian
authors.initials: B
authors.lastname: Crucian
authors.forename: Raymond
authors.initials: R
authors.lastname: Stowe
authors.forename: Satish
authors.initials: S
authors.lastname: Mehta
authors.forename: Peter
authors.initials: P
authors.lastname: Uchakin
authors.forename: Heather
authors.initials: H
authors.lastname: Quiriarte
authors.forename: Duane
authors.initials: D
authors.lastname: Pierson
authors.forename: Clarence
authors.initials: C
authors.lastname: Sams
mesh_terms: D016207:Cytokines / Q000097:blood; D003587:Cytomegalovirus / Q000276:immunology; D005260:Female; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007107:Immune System / Q000276:immunology* / Q000503:physiopathology; D016130:Immunophenotyping; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D013026:Space Flight; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013997:Time Factors
chemical_list: D016207:Cytokines