Space travel appears to weaken astronauts’ immune systems, and researchers believe changes in gene expression are the culprit. These immune deficits aren’t permanent. They disappear when back on Earth, often within weeks, according to new research published June 22 in Frontiers in Immunology. “Here we show that the expression of many genes related to immune functions rapidly decreases when astronauts reach space,” said study lead author Dr. Odette Laneuville, an associate professor of biology at the University of Ottawa in Canada. “The opposite happens when they return to Earth after six months aboard the ISS [International Space Station],” Laneuville added in a journal news release. Astronauts seem more susceptible to infections in space, often getting skin rashes and a variety of other diseases on the ISS, evidence has suggested. They also shed, or emit, more live virus particles, including those for the Epstein-Barr virus; varicella-zoster, which is responsible for shingles; and herpes-simplex-1, the source of “cold sores.” To delve into this, the researchers studied gene expression in leukocytes (white blood cells) in 14 astronauts. Among them were three women and 11 men living on the ISS from 4.5 to 6.5 months between 2015 and 2019. The research team drew blood from each astronaut at 10 time points, including pre-flight, in flight and after their return to Earth. The investigators found that 15,410 genes were differentially… read on > read on >

















