Chronic stress and natural killer cell activity after exposure to traumatic death

The present study examined the effects of working at the crash site of USAir Flight 427 on psychological, cardiovascular, and immunological sequelae of stress within 2 months of the recovery work and again 6 months after the crash.

A total of 159 workers at the crash site and 41 controls were examined within 2 months of the crash and again 6 months after the crash. Subjects were initially grouped according to whether they had contact with human remains. For a finer-grained analysis of exposure to bodies, subjects were also grouped by degree of exposure, determined by the area in which the workers were stationed. Dependent measures included intrusive thoughts, coping styles, and symptom reporting, as well as heart rate and blood pressure, and NK cell number and activity.

Workers exposed to body parts at the actual crash site, and those who were exposed to remains without expecting to be, exhibited more symptoms of stress than workers who saw bodies and body parts at the morgue and those who did not see human remains. Non-morgue workers who were exposed to bodies or body parts had the highest levels of intrusive thoughts at both time points, and the highest NK cell activity at Time 1. NK activity in this group decreased to levels comparable with other groups at Time 2.

Increased NK activity is unusual in chronic stress situations, and may be because of acute stress experienced as a result of being asked to talk and think about the crash. The finding that the more one was exposed to human remains the less distress he or she reported is discussed in terms of adaptation, expectancy, and control.