Mechanistic Clues to Overcome Spaceflight-Induced Immune Dysregulation

Purpose of Review: To recapitulate the latest findings from comprehensive studies of relatively long-duration spaceflight aboard the International Space Station, followed by exciting research published recently that illuminates the means by which we may be able to correct the immune system disturbances associated with spaceflight. Recent Findings: While in space, most astronauts experience immune perturbations that may manifest as a form of immunodeficiency or, alternatively, a hypersensitivity reaction. When it occurs, the dysregulation persists stably for the duration of the mission. T lymphocytes – a population of the adaptive immune system that is essential for life – are particularly prone to spaceflight-induced malaise. Using cells from crewmembers during spaceflight, as well as cells in simulated microgravity model environments, researchers have begun to define specific alterations in antigen recognition, cell signaling, and gene expression patterns that may be responsible, in whole or in part, for the apparent depression in immune cell function. Summary: Given the next major objective of the global space exploration community is voyage to Mars -- which means the missions will be of an unprecedented duration – it is reasonable to hypothesize the crewmembers’ health will be at greater risk than ever before. Thus, our communal goal is to devise a set of countermeasures that will obviate this risk. A prerequisite to this end is an understanding of the mechanisms underlying the immune perturbations.