Our physical health and mental health are really connected. Studies have found that bad experiences and constant stress can change the way we feel, act, and how our body’s defence system works. The health of our system is also important, and the CD45RA/RO ratio helps us understand if our immune system is working properly or not and how well it is working for our age. Our immune system can get weaker with time, and constant stress can make it worse. The CD45RA/RO ratio is a way to measure this and see if our immune system is getting older than it should be. Two types of T-cells:
Naive T-cells (CD 45RA): After we get a new infection, we have naive T-cells that will then “remember” that particular infection. These are the T-cells that will be used to fight the same infection at a later date. Memory T-cells (CD45RO): Every time we have an infection, we make memory T-cells specific to that infection to protect us from having that same infection in the future.
As we become older & lied to chronic stress, the chronic stress will negatively impact the number of naive T-cells produced. Alternatively, there will be an increase in the quantity of memory T-cells produced. As a result, as a consequence of stress, the CD45RA/RO ratio will have changed (as documented by Fagnoni et al., 2000). According to researchers, early trauma and chronic stress may contribute to advancing the ageing process of the immune system. Allostatic load theory states that chronic stress leads to physiological wear and tear, resulting in immune changes associated with inflammation and altered memory of infections(McEwen, 1998).
Read More: When Nostalgia Hurts: Understanding Childhood Trauma and Neglect
Psychological Trauma and Chronic Stress
Trauma, described as psychological, includes both emotional and mental trauma that can occur due to an experience. Trauma can happen in both a child’s life and an adult’s life. Its impact is often more severe and long-lasting in children. If emotional stress keeps the body in a constant state for too long. It will cause Long-term stress as opposed to Short-term stress, which has a very similar effect on the stress response system of the body, e.g., the longer the period of time the body is under stress, the greater the adverse impact will be to an individual’s sleep patterns, mood, heart disease and immune function.
A study on individuals with adverse childhood experiences (ACE). It was demonstrated that there was a corresponding increase in chronic health conditions (both physical and mental health) for those individuals who have experienced early trauma, resulting in an increased risk of developing physical chronic disease as well as developing chronic conditions as an adult (Felitti et al., 1998).
Read More: How Chronic Stress Disrupts Working Memory: The Role of Cortisol Awakening Response
Allostatic Load Theory and Immune Ageing
The concept of allostatic load was first developed by Bruce McEwen, who developed a theory to account for the cumulative impact of chronic stress on physical health (McEwen, 1998). Allostatic load is defined as the “wear and tear” resulting from repeated stress responses.
When an individual is exposed to a stressful situation, their body releases various stress hormones, like cortisol and adrenaline, that facilitate a rapid response in times of danger. However, if an individual experiences ongoing or continuous exposure to stress, these hormones become chronically elevated and can cause damage to a variety of human body systems, notably to the immune system.
Chronic stress can also enhance inflammatory responses, lead to decreased immune regulation, reduce the production of naïve T cells, and produce increased levels of immune exhaustion. Consequently, individuals who have experienced chronic physical trauma or stressors may have immune profiles similar to those of older individuals, despite their biological age.
Trauma, the Brain, and the Immune System
Psychoneuroimmunology shows that there is active dialogue among the brain, nervous system, endocrine system, and immune system. How a person feels (Secgrestrom & Miller, 2004) may be able to affect the functioning of your immune system as you feel. The increased amounts of stress hormones have also been found to elevate certain types of inflammatory markers, including Interleukin-6, Tumour Necrosis Factor-alpha, and C-reactive proteins.
The prolonged elevation of these inflammatory levels in the body can cause the immune system to fail from constant exposure to inflammation. This can also cause your immune cells to become older than they should be due to their accelerated rate of ageing (Miller et al., 2009).
Early Life Trauma and Immune Memory
The early years in a person’s life play a key role in both emotional and immune development. Repeated exposure to stress during this time may contribute to long-term biological change. Researchers refer to this as biological embedding, where early experiences physically shape the body’s systems. Abused and neglected children, as well as those living in poverty or unstable family situations, may demonstrate exposure to inflammatory responses later in life. These changes can also persist into adulthood and impact the formation of memory for immune responses.
Individuals who have been exposed to trauma may produce fewer naïve T-cells, have a greater number of memory T-cells than naïve T-cells, demonstrate increased levels of inflammatory activity, and are at higher risk for developing chronic disease. Further studies suggest that these changes appear to be associated with alterations in the CD45RA/RO ratio, suggesting accelerated immunosenescence (Miller et al., 2009).
Immunosenescence and Accelerated Ageing
Normally, immunosenescence is a natural part of ageing. In general, older adults exhibit lower immune responses and decreased ability to respond to new infections. Current research findings suggest that chronic psychological stress speeds up this process.
This implies that a young adult who has experienced severe trauma may resemble an older adult physiologically at the immune level. Some studies found that chronic stress leads to shorter telomeres, higher oxidative stress levels and decreased flexibility in the immune system, all of which can contribute to faster ageing (Epel et al., 2004). As a result, the CD45RA/RO ratio is useful for understanding how psychological and traumatic events can affect long-term physical health. Importance of the CD45RA/RO Ratio in Mental Health Research
The CD45RA/RO ratio is an important measure because it connects psychological experiences with objective biological changes. This marker reflects how stress from trauma can become manifest in the body through the immune system, rather than simply viewing trauma as emotional pain.
By understanding the relationship between psychological experience and physical embodiment, we will gain knowledge about developing trauma-informed healthcare systems, creating early intervention programs for stress-related medical conditions, identifying those who may be at higher risk for early ageing, and creating greater collaboration between psychology and immunology. It also reinforces supporting emotional well-being for maintaining long-term health.
Read More: The Body Remembers: How Stress, Trauma, and Emotion Shape Autoimmune Disease
Conclusion
The CD45RA/RO ratio reflects many aspects of the immune system, including memory and immunological ageing. In the psychological sense as well as in the physical sense, trauma can reduce the production of new T-cells and increase the production of memory T-cells. Each of these outcomes is consistent with the theories proposed by psychosomatic medicine and the allostatic load theory. The physical effects of inflammation, immune function, and biological age are all closely linked to one another. Therefore, trauma will strongly influence all of these processes.
Therefore, these findings indicate that psychological experiences influence much more than what researchers initially perceived. Trauma can create long-term changes in the immune system. This will ultimately affect an individual’s health throughout his or her life. By better understanding the relationship between psychological stress and immune system ageing. Future Mental Health and Health Care policies may be more effective.
References +
Danese, A., Pariante, C. M., Caspi, A., Taylor, A., & Poulton, R. (2007). Childhood maltreatment predicts adult inflammation in a life-course study. Proceedings of the National Academy of Sciences, 104(4), 1319–1324. https://doi.org/10.1073/pnas.0610362104
Epel, E. S., Blackburn, E. H., Lin, J., Dhabhar, F. S., Adler, N. E., Morrow, J. D., & Cawthon, R. M. (2004). Accelerated telomere shortening in response to life stress. Proceedings of the National Academy of Sciences, 101(49), 17312–17315. https://doi.org/10.1073/pnas.0407162101
FAGNONI, F. F., VESCOVINI, R., MAZZOLA, M., BOLOGNA, G., NIGRO, E., LAVAGETTO, G., FRANCESCHI, C., PASSERI, M., & SANSONI, P. (1996). Expansion of cytotoxic CD8 + CD28 T cells in healthy ageing people, including centenarians. Immunology, 88(4), 501–507. https://doi.org/10.1046/j.1365-2567.1996.d01-689.x
Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards, V., Koss, M. P., & Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. American Journal of Preventive Medicine, 14(4), 245–258. https://doi.org/10.1016/S0749-3797(98)00017-8
Ge, M., E C., & Kj, P. (2011, November 1). Psychological Stress in Childhood and Susceptibility to the Chronic Diseases of Ageing: Moving Toward a Model of Behavioural and Biological Mechanisms. Psychological Bulletin.https://pubmed.ncbi.nlm.nih.gov/21787044
Kiecolt-Glaser, J. K., McGuire, L., Robles, T. F., & Glaser, R. (2002). Psychoneuroimmunology and Psychosomatic Medicine: Back to the Future. Psychosomatic Medicine, 64(1), 15– 28. https://doi.org/10.1097/00006842-200201000-00004
McEwen, B. S. (2006). Protective and damaging effects of stress mediators: central role of the brain. Dialogues in Clinical Neuroscience, 8(4), 367–381. https://pubmed.ncbi.nlm.nih.gov/17290796
Pawelec, G. (2002). T cells and ageing, January 2002 update. Frontiers in Bioscience, 7(4), d1056- 1183. https://doi.org/10.2741/a831 Segerstrom, S. C., & Miller, G. E. (2004). Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry. Psychological Bulletin, 130(4), 601–630. https://doi.org/10.1037/0033-2909.130.4.601
