Last Published:  07/31/19 10:05:30 AM (Central)
Responsible Element: Human Health Countermeasures (HHC)
Status: Open

Initial  State:  At the 2005 inception of the HRP there was little known about the in-flight status of the human immune system.  A wealth of knowledge defined immune dysregulation post-flight, including diminished cellular function, dysregulated cytokine production profiles and physiological stress.  However, it was generally unknown if these observations reflected the in-flight condition.  Several narrow-focus, low ‘n’ in-flight studies did indicate that immune dysregulation could be an in-flight phenomenon, however proper investigation of the various aspects of immunity and stress (innate/adaptive, humoral/cellular, dysfunction among specific cell types, etc.) was lacking.   The reactivation of latent herpesviruses, thought to be a direct consequence of diminished immune function, was well established during short duration spaceflight, but it was unknown if this phenomenon would persist or resolve during long-duration spaceflight.   It is generally believed that such dysregulation would not be a significant clinical risk for orbital flight (despite incidence of immune-related health events on orbit), but that persistent dysregulation could pose a crew health risk during exploration class deep-space missions.  During the intervening period since HRP inception, Integrated Immune has thoroughly characterized certain aspects of adaptive immunity and viral reactivation during short- and long-duration spaceflight.   The new findings confirm that both immune dysregulation and latent herpesvirus reactivation persist during 6-month ISS missions.   Other aspects of immunoreguation remain relatively uninvestigated during spaceflight.   [NOTE:  A thorough compilation of the immune evidence base is available in the 2013 rewrite of the HRP Evidence Book, Immunology Chapter] 

Intermediate Steps/Metrics:
 Analysis of data to determine immune parameters to measure in flight. 


  1. Baseline data characterizing those properties of adaptive immunity and herpes virus reactivation during spaceflight  assayed by the Integrated Immune and Immuno flight studies, included leukocyte distribution, T cell function, cytokine production profiles for adaptive immune cells (T cells, etc.) along with herpesvirus reactivation.   At study completion, Gap closure ~35%. 
  2. Characterize aspects of innate immunity, as defined by those properties assayed by the Salivary Markers flight study, which will assess the distribution and function of innate immune cells (monoyctes, macrophages, dendritic cells, etc.).   At study completion, Gap closure ~45%. 

  3. Characterize other uninvestigated aspects of immunoregulation, stress, virology and crew incidence, including some specific SRP recommendations.  This is planned to be accomplished via a large integrated multi-laboratory internal/external study during the lifespan of ISS. Specific assays will be determined by immune SRP inputs, relevant NASA board inputs, the solicitation process, peer review process, and final approval.This study should essentially close Gap IM-01 (post completion status ~95%).

  4. The remaining ~5% Gap allows for emergent breakthroughs in immunology that occur during the lifespan of these studies.

Approach:  Measurement and characterization of selected immune biomarkers (leukocyte distribution, cellular function, cytokine profiles, etc.) before, during, and after spaceflight.   Specific plan will be to complete the Salivary Markers flight study, propose and gain approvals for subsequent large follow-up study, execute to completion prior to decommissioning of ISS.

Target for Closure
This Gap will close when the effects of spaceflight on human immunity (innate and adaptive) are understood sufficient to interpret clinical risk and the necessity of countermeasures. This determination should be made by a panel comprised of flight surgeons, clinical immunologists, and members of the space-immunology research community.
Risk Risk of Adverse Health Event Due to Altered Immune Response
You are here! Gap IM1: We do not know to what extent spaceflight alters various aspects of human immunity during spaceflight missions up to 6 months.

No Documentation Available