Life in space does strange things to the human body — it stretches the spine, it turns muscles to jelly, and now new research led by NASA shows that spaceflight confuses the immune system, too.
Scientists found that the immune systems of 28 astronauts seemed to be temporarily altered during their six-month missions aboard the International Space Station. It's not yet clear how these changes arise, or whether they pose serious medical risks to today's astronauts. But the findings suggest future spaceflyers on longer missions to Mars or an asteroid could be more susceptible to illness.
"Things like radiation, microbes, stress, microgravity, altered sleep cycles and isolation could all have an effect on crew member immune systems," Brian Crucian, NASA biological studies and immunology expert, who led the study, said in a statement. "If this situation persisted for longer deep space missions, it could possibly increase risk of infection, hypersensitivity, or autoimmune issues for exploration astronauts." [The Human Body in Space: 6 Weird Facts]
Crucian and colleagues looked at blood plasma samples from the astronauts taken before, during and after their spaceflights. The scientists found that the distribution of immune cells in the blood was relatively unchanged throughout the mission.
But some cell activity was quite depressed, and the immune system was not producing appropriate responses to threats, the researchers said. This might explain why some astronauts experience "asymptomatic viral shedding." This phenomenon, described in previous studies, reawakens latent viruses — including common herpes viruses like chickenpox and cytomegalovirus (CMV) — but without any symptoms of illness.
The researchers also found that some cell activity was heightened, and the immune system was having an overly aggressive reaction. This could explain why some astronauts experience increased allergy symptoms and persistent rashes.
The findings were recently published online in the Journal of Interferon & Cytokine Research. The scientists say followup research is needed to determine what kinds of countermeasures (such as radiation shielding, nutritional supplements or drugs) could be taken to combat astronaut immune changes.
"These studies tell us that this is an important issue and that we are measuring the right things," Mark Shelhamer, chief scientist of NASA's Human Research Program, said in a statement. "They also tell us there is no place during spaceflight where we see stabilization of the immune system. This is critical as we pursue longer duration missions and why we are studying this further during the upcoming one-year mission."
Next spring, NASA astronaut Scott Kelly will embark on a yearlong mission aboard the space station alongside Russian cosmonaut Mikhail Kornienko. Kelly's twin brother, retired NASA astronaut Mark Kelly, will serve as an earthly control as NASA scientists probe how spaceflight changes the human body.
Copyright 2014 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Typhoon Lan is expected to strengthen before threatening Japan into this weekend and early next week.
Wet weather could lead to delays in the South and Northwest this weekend, while many top teams will play in ideal mid-October weather.
While most of the games in week 7 won't deal with inclement weather, fans in a few cities may want to have rain gear.
A brief, but major change to autumn weather in the southern United States will be accompanied by a dose of heavy rain and thunderstorms by early next week.
Accumulated cyclone energy, or ACE, measures the strength of hurricanes and tropical storms over their duration, allowing meteorologists to compare different storms and seasons.
Following a quiet start to the week, damp and unsettled weather that swept back into the Pacific Northwest at midweek will stick around through the weekend.
While some locations continue rebuild after Ophelia, Brian will target the British Isles with wind and rain into Saturday.