Does this disappearing organ hold the secret of longevity?

What the report says

Al Jazeera reported on July 24 that scientists are taking renewed interest in the thymus, a small immune gland in the upper chest that shrinks and becomes less active as people age. The organ, located beneath the breastbone and in front of the heart, is where immature immune cells develop into T cells, which help identify infected or cancerous cells and coordinate immune responses.

The report highlights recent research suggesting thymic health may be linked to longer life and better outcomes in major diseases, while emphasizing that the evidence is not yet proof of cause and effect. Al Jazeera cited studies including a March Nature paper led by Harvard Medical School researchers that used artificial intelligence to examine thousands of CT scans and found adults with healthier-looking thymus tissue had lower mortality and lower rates of cardiovascular disease and cancer. Another study in the same journal issue linked thymic health in cancer patients to response to immunotherapy. A 2023 study found higher five-year death and cancer rates among people who had the thymus removed, compared with those who did not.

Paola Bonfanti of University College London told Al Jazeera that the thymus does not fully disappear with age, but much of its active tissue is replaced by fat and connective tissue. She cautioned that healthier people may simply be better able to preserve thymic tissue, rather than the thymus itself being the reason they live longer.

The potential importance is that restoring or preserving thymic function could someday help patients with weakened immune systems, including people undergoing cancer treatment or bone marrow transplantation. Al Jazeera also noted Nature’s reporting that Tolerance Bio is developing an antibody intended to slow thymic shrinkage, with clinical trials planned next year.