The thymus gland is positioned in the upper part of the chest cavity, directly behind the sternum. It is pinkish-gray in color and blends in with the surrounding tissue as you age. Two irregularly shaped parts make up the thymus, and though it continues to grow throughout puberty, the gland then begins to diminish in size.

The role of the thymus gland is to process lymphocytes, which are white blood cells that travel the body through the bloodstream. They stop at lymph nodes to ensure everything is working properly, and if not, it is believed that they jump into action to fix any issues. These T-lymphocytes, or T-cells, play a part in cellular immunity by blocking the invasion of harmful foreign agents, viruses, and bacteria. They also aid in preventing the abnormal cell growth that occurs with cancer.

If the thymus gland is removed in infancy, the immune system will never fully develop. There is a great degree of infection risk in patients who have no thymus gland, or whose thymus never developed properly. The majority of lymphocyte production happens early in life, so the thymus gland deteriorates with age. In youth, the thymus will reach the size of an apple, but it is reduced to the size of a small marble in the elderly. By the time a person reaches senior citizen status, it is likely their thymus is barely discernible from surrounding fatty tissues.

This degenerative effect is what kept the medical community from understanding the important immunity function of the thymus gland, but experiments in the 1960's proved it was indeed a necessary organ. Much thymus research has been conducted in the early part of the 21st century as scientists continue to probe the relationship between thymus gland function and immunity. Studies are being conducted to determine whether or not regenerating the thymus gland in the aged will improve immunity and decrease the risk of cancer.

If the thymus gland studies prove correct, this can have an incredibly positive impact on the treatment of numerous diseases and conditions. All auto immune diseases, including multiple-sclerosis, arthritis, lupus, and diabetes could be managed more effectively if scientists are able to manipulate the immune response of the thymus gland. Cancer and AIDS are two of the biggest diseases that would be affected, and the implications of tests done on mice have led many to expect a positive effect in the near future.