A recent study published in the New England Journal of Medicine emphasizes the importance of the thymus for adult health, cancer prevention, and potential autoimmune protection.

T cells are produced by the thymus gland before birth and throughout childhood. It is sometimes removed during adulthood for the convenience of cardiac surgery because it is thought to be nonfunctional.

Researchers assessed 1,146 adults with thymus removal during surgery, comparing death and cancer risks to demographically matched cardiothoracic surgery patients.

The researchers also measured T-cell production and blood levels of immune-related molecules in a subset of patients.

Senior author David T. Scadden, MD, director of the Center for Regenerative Medicine at MGH and co-director of the Harvard Stem Cell Institute said -

“By studying people who had their thymus removed, we discovered that the thymus is absolutely required for health. If it isn’t there, people’s risk of dying and risk of cancer is at least double.

This indicates that the consequences of thymus removal should be carefully considered when contemplating thymectomy.”

After analyzing thymectomy patients with over five years of follow-up, higher overall mortality and cancer mortality were observed compared to the general US population.

Although autoimmune disease risk didn’t significantly differ between thymectomy and control groups overall, excluding patients with prior infection, cancer, or autoimmune control followed for about 14.2 years, lower new T cell levels and elevated pro-inflammatory molecules were found in thymectomy patients.

Scadden and colleagues plan to explore how various adult thymus function levels impact health. He added -

“We can test the relative vigour of the thymus and define whether the level of thymus activity, rather than just whether it is present, is associated with better health.”