The ability of the immune system to fight disease may be affected by space flight. Postflight analyses of blood from Apollo, Skylab and Russian Soyuz crewmembers in the late 1960's and 1970's showed an increase in white blood cell counts, and decreased numbers of lymphocytes. These studies also suggested that there were changes in the ability of lymphocytes to react to foreign materials. A study conducted between 1981-1984 on 41 Space Shuttle astronauts showed that the absolute number of lymphocytes circulating in the body was decreased and the number of circulating neutrophils was increased. This effect is generally thought to result from the immune system's ability to detect changes in body fluid distribution, and other stresses, and to make compensating adjustments in the numbers of circulating white blood cells. Over recent years, Russian scientists have made observations of cosmonaut's immune condition after long stays in space. Some of the changes include alterations in the function of different types of lymphocytes. Immunologists are trying to better understand these and other changes imposed by space flight.
The NASA-Mir program included several immunology experiments that were designed to understand changes in the immune system's components that occur during long stays in space. U. S. and Russian scientists studied changes in circulating immune cells, assessed the functional changes resulting from space flight in the peripheral immune cells, and determined the cellular/molecular mechanisms of the space flight-induced immune alterations. Furthermore, it has been established that stress lowers the ability of the immune system to resist foreign invaders, and can induce the reactivation and release of dormant viruses from tissues and cells into the body fluids. Therefore, when both of these events occur, the body becomes susceptible to infection.
Assessment of Humoral Immune Function during Long-Duration Space Flight (Phase 1A)
Assessment of Humoral Immune Function during Long-Duration Space Flight
Phenotypic and Functional Analysis of Peripheral Mononuclear Cells during Long-Duration Space Flight
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Page last updated: 07/16/1999