But not all immune systems age at the same rate. In our recently published study, my colleagues and I found that social stress is associated with signs of accelerated aging of the immune system.
Stress and immunosenescence
To better understand why people of the same chronological age may have different immunological ages, my colleagues and I analyzed data from the Health and Retirement Survey (HRS), a large, nationally representative survey of American adults over the age of 50.
HRS researchers ask participants about different types of stressors they have experienced, including stressful life events, such as job loss; discrimination, such as being treated unfairly or being denied attention; significant lifelong trauma, such as a family member having a life-threatening illness; and chronic stress, such as financial stress.
Recently, HRS researchers have also begun collecting blood from a sample of participants, counting the number of different types of immune cells present, including white blood cells. These cells play a central role in the immune responses to viruses, bacteria, and other invaders. This is the first time such detailed information on immune cells has been collected in a large national survey.
Analyzing data from 5,744 HRS participants who provided blood and answered questions from the stress survey, my research team and I found that the people who experienced the most stress had a higher proportion. “naive” T cell discharge: Fresh cells needed to cope with new invaders. the immune system has not been found before.
They also have a higher proportion of “late-differentiated” T cells, older cells that have depleted their ability to fight invaders, and instead produce proteins that can increase harmful inflammation. People with lower proportions of newer T cells and high proportions of older T cells have an older immune system.
However, after controlling a poor diet and low exercise, the connection between stress and accelerated immune aging was not as strong. This suggests that improving these health behaviors could help offset the dangers associated with stress.
Similarly, after considering potential exposure to cytomegalovirus, a common virus, usually asymptomatic known to accelerate immune aging, the link between stress and aging of immune cells was reduced. .
Although CMV normally stays dormant in the body, researchers have found that stress can cause CMV to explode and force the immune system to compromise more resources to control the reactivated virus.
Sustained infection control can consume naive T cell supplies and result in more depleted T cells circulating throughout the body and causing chronic inflammation, a major contributor to age-related disease.
Understanding immune aging
Our study helps to clarify the association between social stress and faster immune aging. It also highlights potential ways to slow down immune aging, such as changing the way people cope with stress and improving lifestyle behaviors such as diet, smoking, and exercise.
The development of effective cytomegalovirus vaccines can also help relieve the aging of the immune system.
It is important to note, however, that epidemiological studies cannot fully establish cause and effect. Further research is needed to confirm whether stress reduction or lifestyle changes will lead to improvements in immune aging and a better understanding of how stress and latent pathogens such as cytomegalovirus interact to cause disease and dead.
We are currently using additional data from the Health and Retirement Study to examine how these and other factors such as childhood adversity affect immune aging over time.
Less aged immune systems are better able to fight infections and generate protective immunity from vaccines. Immunosecurity may help explain why people are more likely to have more severe cases of COVID-19 and a weaker response to vaccines as they age.
Understanding what influences immune aging can help researchers better address age-related disparities in health and disease.
Eric Klopack, postdoctoral researcher in gerontology, University of Southern California.
This article is republished from The Conversation under a Creative Commons license. Read the original article.