Longevity & AgingThymus Keeps Working Into Old Age — Sex and Smoking Determine How Much
A study of adults aged 50+ undergoing cardiac surgery found that functional thymic tissue persists within mediastinal fat, continuing to generate new T cells late in life. Using flow cytometry, RNA sequencing, and TCR sequencing, researchers confirmed active thymopoiesis in roughly half of patients. Thymic output was highly variable and not predicted by chronological age alone. Women showed significantly higher levels of recent thymic emigrants (RTEs) in blood than men, and nonsmokers retained more thymic activity than smokers. Higher thymic output correlated with greater T cell receptor diversity, better immune protection against respiratory infections, and lower epigenetic age — suggesting that preserving thymic function may meaningfully support immune health and longevity in older adults.
