A WEHI study could help solve a long-standing mystery into why a key immune organ in our bodies shrinks and loses its function as we age.
The thymus is essential for good health due to its ability to produce special immune cells responsible for fighting infections and cancer.
In a world-first, researchers have uncovered new cells that drive this ageing process in the thymus -
significant findings that could unlock a way to restore function in the thymus and prevent our immunity from waning as we age.
T cells, also known as T lymphocytes, are white blood cells that play a crucial role in the immune system. They are essential for identifying and responding to pathogens, such as viruses and bacteria, and for eliminating infected or cancerous cells.
The thymus sits behind the breastbone. It is the only organ in the body that can make T cells.
The thymus is also the first organ to shrink as we get older. As this happens, the T cell growth areas in the thymus are replaced with fatty tissue, diminishing T cell production and contributing to a weakened immune system.
While the thymus is capable of regenerating from damage, researchers have been unable to figure out how to unlock this ability and boost immunity in humans as they age.
WEHI Laboratory Head Professor Daniel Gray said the new findings, published in Nature Immunology, could help solve this mystery.
"The number of new T cells produced in the body significantly declines after puberty, irrespective of how fit you are. By age 65, the thymus has virtually retired," said Professor Gray.
"This weakening of the thymus makes it harder for the body to deal with new infections, cancers and regulate immunity as we age.
"This is also why adults who have depleted immune systems, for example due to cancer treatment or stem cell transplants, take much longer than children to recover.
"These adults 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."
"Our discovery provides a new angle for thymic regeneration and immune restoration, could unravel a way to boost immune function in vulnerable patients in the future," added Professor Gray.
