The immune system is meant to protect the body from infection and disease. But with age, it can become less capable of doing so. However, Mayo Clinic researchers have found that some older people maintain "immune youth" - a new term coined by Mayo researchers to explain a young immune system in someone over age 60.
"We are studying why some individuals have a 'fountain of youth' in their immune systems. We want to learn from them," says Cornelia Weyand, M.D., Ph.D., a Mayo Clinic rheumatologist and clinician-scientist. She is a lead author on a perspective paper published in Nature Aging.
Dr. Weyand's research team discovered this cellular fountain of youth in more than 100 older patients who came to Mayo Clinic to receive treatment for an autoimmune disease that affects the arteries, including the aorta, called giant cell arteritis. Dr. Weyand and colleagues found in the diseased tissue of these patients specialized immune cells, called stem-like T cells. These immune cells behave like young stem cells that usually regenerate and aid healing and growth; but in this case, they were spreading the disease. This team of researchers also discovered autoimmune stem cells in humans previously.
"We observed that these patients have very young immune systems despite being in their 60s and 70s. But the price they pay for that is autoimmunity," she says.
Autoimmunity is when the immune system mistakenly attacks healthy tissues and organs.
In addition, the researchers saw that the immune checkpoint inhibitors that regulate the immune system were not working properly.
Benefits of immune system aging
"Contrary to what one may think, there are benefits to having an immune system that ages in tandem with the body," says Jörg Goronzy, M.D., Ph.D., a Mayo Clinic researcher on aging who is a co-lead author of the paper. "We need to consider the price to pay for immune youthfulness. That price can be autoimmune disease."
Immune aging is a sophisticated adaptation mechanism that the immune system can use to prevent autoimmune disease, say the researchers.
They are in the process of developing new diagnostic tests that will help find patients and healthy individuals who carry high numbers of immune stem cells and may be predisposed to autoimmune disease later in life. The research is part of a larger effort at Mayo Clinic called the Precure initiative, focused on developing tools that empower clinicians to predict and intercept biological processes before they evolve into disease or progress into complex, hard-to-treat conditions.
Review the study for a complete list of authors, disclosures and funding.
Additional resources:
Mayo Clinic advances research on mysterious blood vessel disease
