The immune system normally weakens with aging. Immunosenescence, the term for the aging of the immune system, may have a role in age-related health issues including cancer and cardiovascular disease, and also the reduced effectiveness of immunizations in older individuals.
However, the pace of aging of the immune system varies across individuals. Social stress has been linked to indicators of accelerated immune system aging, according to a study published only lately.
A new research project
Researchers from the University of Southern California (USC) analyzed data from the Health and Retirement Study (HRS), a large, nationally representative study of US individuals over the age of 50, to better understand why persons of the same chronological age might have varied immunological ages.
For example, HRS researchers questioned respondents about stressful experiences such as loss of employment; discrimination, such being treated unjustly or refused treatment; substantial lifetime trauma, like a family member’s having a potentially life-threatening disease; and chronic stress, like money issues.
White blood cells, as well as other kinds of immunological cells, have recently been counted by HRS researchers in participants’ blood samples. Immune responses to viruses, bacteria, and other pathogens are heavily dependent on these cells. This is the first nationwide study to gather such comprehensive data on immune cells.
USC researchers analyzed data from 5,744 HRS selected respondents who both offered blood and responded questionnaire survey regarding stress and discovered that individuals who were more stressed had a smaller share of “naive” T cells – fresh cells required to take on new intruders that the immune system hasn’t seen before.
T cells in the senior population are more likely to be “late differentiated,” meaning they have lost their capacity to fend off intruders and are now more likely to create proteins that promote inflammation. A person’s immune system seems to be older if they have a low percentage of younger T cells and a high percentage of older T cells.
This research sheds light on the link between increased social stress and accelerated aging of the immune system. Changes in stress management and better lifestyle habits including food, smoking, and exercise may help decrease the aging of the immune system.