Immune function declines with unemployment and recovers after stressor termination.

Objective: To examine the effect of unemployment on natural killer cell cytotoxicity (NKCC) and, in a subsample of persons who become re-employed, to determine if, after termination of the stressor, immune values recover to levels similar to matched controls.

Methods: One hundred unemployed and 100 matched employed healthy men and women, aged 29 to 45 years, were followed for 4 months with monthly blood samples taken to measure NKCC, the ability of NK cells to kill target cells. Twenty-five participants obtained employment before the end of the study, leaving 75 unemployed (and 75 employed) participants in the main sample. For unemployed participants who obtained employment before the end of the study, subsample analyses compared NKCC levels before and after obtaining a new job.

Results: The persistently unemployed sample had significantly lower NKCC levels for all three effector:target ratios (100:1, p = .0004; 50:1, p = .002; and 25:1, p = .02) when compared with the matched employed sample. There were no significant gender effects. In the subsample analyses, NKCC was significantly higher after the participants became employed, compared with their unemployed period, with substantial "recovery" of immune function (44%-72%) compared with values from the steadily employed group.

Conclusions: Chronic stress is associated with persistent NKCC impairment. When the chronic stressor is terminated, however, the immune cell functional capacity quickly begins to recover. We believe this is the first study in humans to document immune function recovery after the definable end of a chronic stressor.