Psychological stress increases human T cell apoptosis in vitro

Objectives: Recent studies have shown that apoptosis is involved in stress responses. The present study examined if stressors increase in vitro apoptosis of peripheral blood T lymphocytes in a dose-dependent manner. Methods: Daily subjective stress was quantitatively analyzed in 40 nonsmoking men with a daily hassles questionnaire. Apoptosis of T lymphocytes was measured by flowcytometry using Annexin V/PI double staining method after 0, 12, and 24 h of culture in the presence or absence of dexamethasone (DEX). Using a cross-sectional design, the current study examined the relationship between stress and in vitro apoptosis of T cells. Results: Results showed that apoptosis of T lymphocytes in vitro has a significant correlation with stress and age. Stress was positively correlated with percentage of apoptosis in T cells after 12 h of culture, irrespective of DEX treatment. Age was positively correlated with the percentage of T cell apoptosis after 0 and 12 h of coculture with DEX. Conclusions: These results indicate that age-related apoptosis and stress-related apoptosis of T cells are modulated through different mechanisms. This is the first study to show that in vitro lymphocyte apoptosis is influenced by daily stress in a dose-dependent manner.