Elevated Stress Hormone Levels Relate to Epstein-Barr Virus Reactivation in Astronauts

Objective The objective of this study was to determine the effects of stress and spaceflight on levels of neuroendocrine hormones and Epstein-Barr virus (EBV)–specific antibodies in astronauts. Methods Antiviral antibody titers and stress hormones were measured in plasma samples collected from 28 astronauts at their annual medical exam (baseline), 10 days before launch (L−10), landing day (R+0), and 3 days after landing (R+3). Urinary stress hormones were also measured at L−10 and R+0. Results Significant increases (p < .01) in EBV virus capsid antigen antibodies were found at all three time points (L−10, R+0, and R+3) as compared with baseline samples. Anti-EBV nuclear antigen antibodies were significantly decreased at L−10 (p < .05) and continued to decrease after spaceflight (R+0 and R+3, p < .01). No changes were found in antibodies to the nonlatent measles virus. The 11 astronauts who showed evidence of EBV reactivation had significant increases in urinary epinephrine and norepinephrine as compared with astronauts without EBV reactivation. Conclusion These findings indicate that physical and psychological stresses associated with spaceflight resulted in decreased virus-specific T-cell immunity and reactivation of EBV.