Influence of life stress on immunological reactivity to mild psychological stress

This study investigated the effects of self-reported life stress and locus of control on reactivity of several immune parameters to a mild and short-lasting interpersonal stressor. Subjects were 86 male teachers aged 24 to 55 years. Immune reactivity was defined as changes in numbers of monocytes. T-lymphocytes and subsets, HLA-DR+ cells, and NK cells as well as changes in (in vitro) proliferative responses of peripheral blood lymphocytes to the antigens PHA and PWM. Multiple regression analysis was used to study the interaction effects of life stress and locus of control by experimental condition on immune reactivity. Life stress, but not locus of control, influences reactivity of the immunological parameters to the stressor. In particular, high numbers of daily hassles were associated with stressor-induced decreases in numbers of T cells and NK cells in peripheral blood. On the other hand, numbers of HLA-DR+ cells in high life stress scorers decreased only slightly during the stressor, whereas they increased in the control condition. The findings suggest that accumulated life stress is related to reactivity of immunological parameters to subsequent experimental stress. Possible physiological explanations and implications of these effects are discussed.