PBMC isolation and processing
PBMCs were obtained using the Ficoll gradient method from a cohort of 16 subjects enrolled in the INDEX2020 study. The collection process involved obtaining samples first at low altitude (LA) and then, after a span of 3 days, at high altitude (HA). Out of the 16 subjects, paired PBMC samples were collected from 6 subjects in the control group and 6 subjects in the DEX-p group, both at LA and HA, resulting in a total of 24 samples. Additionally, from the remaining 4 subjects, one unpaired PBMC sample from each time point in both groups was added, resulting in a total of 28 samples. Briefly, 8ml blood samples were drawn in EDTA-containing tubes. An equal amount of PBS was added to the blood and laid over to Ficoll-containing tubes (Cat.#17-144-02, GE Healthcare). Subsequently, the tubes were centrifuged at 300 g in swinging bucket rotors at room temperature (23°C) for 30 min, with no brakes. The buffy coat layer was collected, transferred into a 15 ml tube and washed using an equal volume of PBS. The PBMCs were pelleted by centrifuging at 300 