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Alteration in human mononuclear leucocytes following space flight
R T Meehan1, L S Neale, E T Kraus
1Department of Medicine, University of Colorado Health Science Center, Denver 80262.
Immunology
|July 1, 1992
Summary
Space flight alters astronaut immune cells, decreasing lymphocytes and natural killer cells while increasing monocytes. This may explain observed immunological and endocrine changes post-flight.
Area of Science:
- Immunology
- Space Medicine
- Cell Biology
Background:
- Astronauts exhibit reduced immune cell proliferation after space flight.
- Understanding space flight's impact on immune cell subpopulations is crucial for crew health.
Purpose of the Study:
- To investigate the effects of space flight on peripheral blood mononuclear cell subpopulations.
- To identify specific immune cell changes in astronauts before, during, and after space missions.
Main Methods:
- Collected peripheral blood samples from 30 astronauts pre-flight, upon landing, and 3 days post-flight.
- Utilized flow cytometry to analyze cell counts and subpopulations (T-cells, B-cells, monocytes, NK cells).
- Performed phenotypic analysis for hormone receptor expression on monocytes.
Main Results:
- Increased total leucocytes, granulocytes, and monocytes post-flight; decreased lymphocytes.
- Significant reductions in T-inducer and T-cytotoxic lymphocytes upon landing.
- Elevated monocyte counts, with a novel population negative for insulin/IGF-1 receptors observed.
Conclusions:
- Space flight induces significant shifts in immune cell populations, notably increasing monocytes.
- A novel, potentially stress-related monocyte subset may be activated during space missions.
- These immune alterations may underlie observed post-flight immunological and endocrine dysfunctions.
