Social stress accelerates the aging of the immune system


Los Angeles – Job loss, marital crisis, or discrimination in daily life are likely to affect the immune system. After studying at Proceedings of the National Academy of Sciences (PNAS 2022; DOI: 10.1073 / pnas.2202780119), social stress accelerates the decline of the immune system in old age.

This was partly due to obesity and an unhealthy lifestyle. However, latent cytomegalovirus (CMV) infections may also play a role.

The competencies of the immune system decrease with age. This immune aging is reflected in an increased number of terminally differentiated “worn-out” T cells that are no longer available to fight pathogens or eliminate cancer cells.

At the same time, the supply of so-called naive, ie “fresh” B and T cells, which can respond to new challenges, is shrinking. Older people are therefore more susceptible to infectious diseases, as recently shown by coronapandemia. An increase in cancer and cardiovascular disease is also associated with aging immunity.

Doctors at the Leonard Davis School of Gerontology in Los Angeles studied the effects of social stress on immune senescence. To this end, the answers of 5,744 participants in the “Health and Retirement Study” in the questionnaire were compared with the results of a blood test.

The study accompanies a group of seniors to examine the effects of aging on health. Every 2 years, participants are asked about their lifestyle and health. Blood samples are also taken.

In the questionnaire, participants were asked about stressful life events (eg job loss or robbery), chronic stress (eg financial problems or marital crises), discrimination in everyday life (lack of respect from others) or lifelong disadvantage (disadvantage in working life). ) and life traumas (loss of a partner, drug problems in the family).

All these experiences could directly or indirectly damage the immune system. Direct damage would be conceivable through the activation of hormonal stress responses. Indirectly, social stress can lead to depression or neglect.

According to Eric Klopack and colleagues, all 5 aspects had a negative effect on the immune system. Experiencing life trauma and chronic stress was associated with a lower percentage of naive CD4 cells. Discrimination and chronic stress increased the proportion of terminally differentiated CD4 cells. Stressful life events, lifelong disadvantages and life trauma were associated with a lower percentage of naive CD8 cells and an increase in terminally differentiated CD8 cells.

Part of the association, according to Klopack, was caused by lifestyle factors such as obesity, smoking, alcohol consumption and low levels of education. Thus, social stress would indirectly accelerate immune senescence.

Infections can be another factor that doesn’t seem to seem like social stress at first glance. The marker here was CMV seropositivity. CMV is a herpes virus.

Infections are chronic, but usually do not cause symptoms. Nevertheless, they are a challenge for the immune system, which must prevent reactivation. In the long run, according to Klopack, this could lead to a weakening of the immune system.

Stress can promote reactivation of CMV infection, as is known in other herpesviruses, such as herpes labialis or chickenpox / zoster. In fact, part of the stress-induced immune aging can be attributed to CMV seropositivity. Vaccination, which is not currently available, could therefore have a positive effect on immune senescence, Klopack believes. © rme /

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