Or maybe it’s that the immune system, which never evolved for survival in space, simply gets confused. His body showed signs of intense stress, and his immune system was in high gear. “This is why you want to see it in more people.”Despite that shock, Mr. Kelly’s body mostly returned to preflight condition. The strange lengthening of Mr. Kelly’s telomeres disappeared after less than 48 hours on Earth. In fact, Dr. Bailey and her colleagues started finding many cells with telomeres that were shorter than before Mr. Kelly went to space.

Source: International New York Times April 11, 2019 18:01 UTC