February 22, 2016
A new study led by a researcher at the University of North Carolina’s Gillings School of Global Public Health has found that people affected by post-traumatic stress disorder (PTSD) may also experience an unnatural decline or “aging” of their immune system.
The study, centered in Detroit, Michigan, used both PTSD screening and blood samples in its assessment of 85 individuals aged 19 to 83 years. Titled “PTSD is associated with an increase in aged T cell phenotypes in adults living in Detroit,” the study’s lead author was Allison Aiello, PhD, professor of epidemiology at the Gillings School.
Aiello and co-authors, including Lydia Feinstein, PhD, postdoctoral research associate in epidemiology at the Gillings School, collected data from adults who participated in the community-based Detroit Neighborhood Health Study. The researchers examined the makeup of participants’ T cells.
After adjusting analytic models to account for other factors that can affect the immune system (including age, gender, race/ethnicity, education, smoking status and medication use), the research team found that PTSD experienced within the past year was associated with statistically significant differences in multiple T cell markers of immunological aging.
As people age, the immune system becomes less effective, which is likely the reason cancer is more common among the elderly, and why older individuals have a harder time fighting illnesses such as pneumonia and influenza. In particular, previous studies have shown that the makeup of T cells changes as people get older. T cells (short for Thymocytes cells) are a type of white blood cell that play a central role in immunity.
PTSD is a stress-related psychological and physical response to past traumatic events that can manifest in feelings of overwhelming fear and helplessness. It has been linked to autoimmune conditions such as rheumatoid arthritis and psoriasis, suggesting that it may affect the immune system.
The past-year findings of this study suggest that the impact of PTSD on the immune system may be greatest in the period directly following an episode of PTSD symptoms. The researchers found, however, that individuals who had experienced PTSD at some earlier point in their lifetime also demonstrated differences in several T cell parameters.
“These findings add to the mounting evidence that psychosocial stress is indeed linked with accelerated aging of the immune system,” Aiello says. “More research is needed to understand exactly how post-traumatic stress changes the makeup of T cells, but it is clear that individuals suffering from PTSD also are likely to experience suppressed immunity.”
The full study was published online in advance of the May issue of the journal Psychoneuroendocrinology.