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Study suggests spaceflight may decrease human immunity NASA-DFRC NEWS RELEASE Posted: September 28, 2004 A NASA-funded study has found the human body's ability to fight off disease may be decreased by spaceflight. The effect may even linger after an astronaut's return to Earth following long flights. In addition to the conditions experienced by astronauts in flight, the stresses experienced before launch and after landing also may contribute to a decrease in immunity. Results of the study were recently published in "Brain, Behavior, and Immunity." The results may help researchers better understand the affects of spaceflight on the human immune response. They may also provide new insights to ensure the health, safety and performance of International Space Station crewmembers and future spacefarers on extended missions. "Astronauts live and work in a relatively crowded and stressful environment," said Duane Pierson, the study's principal investigator and NASA Senior Microbiologist at Johnson Space Center, Houston. "Stresses integral to spaceflight can adversely affect astronaut health by impairing the human immune response. Our study suggests these effects may increase as mission duration and mission activity demands increase," he added. The white blood cell count provides a clue to the presence of illness. The five main types of white cells work together to protect the body by fighting infection and attacking foreign material. The most prevalent white blood cells are called neutrophils. From 1999 to 2002, scientists from NASA, Enterprise Advisory Services, Inc., of Houston, and the Boston University School of Medicine compared neutrophil functions in 25 astronauts. They made comparisons after five-day Space Shuttle missions and after nine to 11 day missions. Researchers found the number of neutrophils increased by 85 percent at landing compared to preflight levels. Healthy ground control subjects, who did not fly, exhibited no more than a two percent increase. Researchers also discovered functions performed by these cells, specifically ingestion and destruction of microorganisms, are affected by factors associated with spaceflight. The effect becomes more pronounced during longer missions. The increase in astronaut neutrophil numbers resulted in a corresponding increase (more than 50 percent) in total white blood cell counts at landing. The increase is a consistent consequence of stress. Pierson emphasized that "no astronauts in the study became ill; however, longer exploration missions may result in clinical manifestations of decreased immune response." Researchers concluded the general effect of spaceflight, pre- and post flight-related stress decreases the ability of crewmembers' neutrophils to destroy microbial invaders. This finding suggests crewmembers returning from longer missions may be briefly more susceptible to infections than before launch, because these cells are not as efficient in ingesting and destroying infectious agents. "Having a better understanding of the impact of stress on immunity will help us better understand the risks of infectious disease for Space Station crewmembers and future travelers on long-duration missions," Pierson said. |
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NASA's X-43A research craft and its Pegasus rocket booster complete a captive carry test flight aboard a B-52 launch aircraft. (1min 48sec file)
See damage to the Vehicle Assembly Building, the Saturn 5 Center and other facilities at Kennedy Space Center caused by Hurricane Jeanne. (4min 31sec file)
Jim Kennedy, director of the Kennedy Space Center, and Col. Mark Owen, 45th Space Wing commander, hold a news conference on Monday, Sept. 27 to provide a preliminary report on damage from Hurricane Jeanne at KSC and Cape Canaveral Air Force Station. (49min 30sec file)
Cameras aboard the International Space Station captured these views of Hurricane Jeanne on Saturday, Sept. 25 as the storm approached Florida. (3min 59sec file)
International Space Station program manager Bill Gerstenmaier holds a news conference Sept. 24 to discuss problems with the oxygen generation system and Expedition 10 launch preparations. (44min 06sec file)
Scientists describe a cosmic hurricane in this news conference from Sept. 23, explaining how two merging galaxy clusters churn high-pressure shock waves that leave thousands of galaxies strewn in the wake. (53min 24sec file)
The three men to launch aboard the next Soyuz spacecraft bound for the International Space Station -- Expedition 10 commander Leroy Chiao, flight engineer Salizhan Sharipov and Russian taxi cosmonaut Yuri Shargin -- hold a pre-flight news conference near Moscow on Sept. 23. (43min 05sec file)
Former International Space Station commander Mike Foale radioed current ISS science officer Mike Fincke on Sept. 22 to discuss actvities and work aboard the outpost. (5min 01sec file)
Expedition 9 commander Gennedy Padalka and flight engineer Mike Fincke talk about life aboard the International Space Station during an in-flight educational event with students at the Carnegie Science Center in Pittsburgh. (19min 00sec file)
The International Space Station's Expedition 9 crew hold an educational talk with students and members of the National Guard Bureau in Charleston, West Virginia. (19min 53sec file)