Astronauts’ immune systems go haywire after space trips - study

A study by the European Space Agency (ESA) has revealed that spending time in space has a dramatic effect on the immune systems of astronauts.

The appropriately-named “Immuno” experiment involved testing astronauts for stress-related hormones in saliva and urine samples, as well as testing blood taken both in space and then on return to earth. The astronauts also filled out a questionnaire to assess their own levels of stress.

Blood samples taken back on earth were contaminated with fungi, bacteria and herpes, suggesting the immune system had become hyper-alert to potential illness-inducing pathogens due to the stress of space travel.

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The blood tests suggest that the bodies of astronauts had adapted to the zero-germ environment of the International Space Station and then had completely overreacted to perceived threats of disease and infection when back home.

“What would form a mild immune response in the blood of a healthy person on Earth seems to cause immune cells in astronauts to go haywire, overreacting to some of the foreign threats,” said lead investigator Professor Alexander Choukèr, whose study took five years.

“What was striking and unexpected was the ambiguous immune response we saw in the astronauts’ blood – we saw an over-reaction coupled with severe immune suppression in some areas.”

ESA astronaut and medical doctor André Kuipers, who has traveled to the International Space Station, remarked that he noticed a stark contrast in his health and fitness when he returned from his six-month mission: “Back on earth, I felt 100 years old for a few months.”

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The potential role of weightlessness in this phenomenon has yet to be determined, and further research is currently underway in Antarctica.

Meanwhile, astronauts Scott Kelly and Mikhail Korniyenko returned from their year-long mission aboard the ISS earlier this month as part of the NASA and Roscosmos Human Research Program designed to ascertain how space exploration can affect human health.

As part of that study, the astronauts’ bone density, muscle mass, cardiovascular function, sleep patterns and radiation exposure will be investigated.