Why retiring means our immunity gets far weaker too

Scientists have discovered why a key organ retires at the same time as we do – stopping the production of cells that are vital to good health.

The thymus produces T cells, which help the body to fight infection and disease. But it virtually stops working around the age of 65, meaning our immune systems become far weaker.

With age, the thymus – located behind the breastbone – shrinks and the T-cell-producing areas are replaced with fatty tissues, while ‘scarring’ prevents regeneration.

Treatments for cancer also damage the thymus, making recovery from infection a lot slower for young people with the disease.

The thymus produces T cells (seen fighting a cancer cell in an illustration), which help the body combat infection and disease

The team behind the groundbreaking research say their findings could be significant in the development of immune-boosting therapies for over-60s and those undergoing cancer treatment. 

Co-author Dr Kelin Zhao, of the WEHI research institute in Melbourne, Australia, said: ‘This knowledge enables us to investigate whether these cells can be therapeutically targeted in future to help turn back the clock on the ageing thymus and boost T cell function in humans as we get older. This is the goal our team is working towards.’

Professor Daniel Gray, laboratory head at WEHI, said: ‘Adults who have depleted immune systems… need years to recover their T cells – or sometimes never do – putting them at higher risk of contracting potentially life-threatening infections for the rest of their lives.

‘Exploring ways to restore thymic function is critical to finding new therapies that can improve outcomes for these vulnerable patients and find a way to ensure a healthy level of T cells are produced throughout our lives.’

Dr Gray added: ‘Our discovery provides a new angle for thymic regeneration and immune restoration and could unravel a way to boost immune function in vulnerable patients in the future.’