Consequences of longterm Confinement on Immunity in the Sub-Antarctic Islands

Prolonged isolation in extreme environments such as Antarctic stations or space missions is associated with significant alterations of the immune system, including increased infection rates and viral reactivations (notably Herpesviridae). These immune changes involve both innate and adaptive immunity and are thought to result from multifactorial stressors such as chronic psychological stress, circadian rhythm disruption, and environmental constraints. Despite accumulating evidence from spaceflight and Antarctic overwintering studies, extensive immune profiling is lacking to expand the understanding of pathophysiology of immune adaptation during long-term isolation.
The CHOICE Kerguelen study aims to characterize the immune consequences of a one-year confinement in the French sub-Antarctic Kerguelen Islands. This prospective study will enroll healthy civic service volunteers stationed at Port-aux-Français from November 2025 to November 2026, in collaboration with the French Polar Institute (IPEV), Angers University Hospital, and Professor Alexander Chouker’s team at LMU Munich. Clinical, environmental, and immunological data will be collected at five time points: before departure and every three months during overwintering.
A wide range of biological samples (blood, saliva, stool, urine, hair) will be collected and analyzed to evaluate changes in immune cell populations (by flow cytometry and RNAseq), inflammatory profiles (cytokine panels), viral reactivations (EBV, CMV, HSV, TTV), stress hormones, and fecal microbiota composition.
A secondary objective is to screen for asymptomatic H5N1 infection in the context of an ongoing avian influenza outbreak affecting birds and marine mammals in sub-Antarctic ecosystems.
We hypothesize that long-term confinement in Kerguelen induces an immune profile resembling inflammaging, with stress-induced dysregulation of both innate and adaptive immunity. This study will enhance our understanding of immune adaptation in extreme environments and may have broader implications for managing chronic stress and immune vulnerability in chronically ill patients.