Shaking up immunity: psychological and immunologic changes after a natural disaster

The 1994 Northridge earthquake created life disruption and psychological distress for employees of the nearby Sepulveda VA Medical Center. We were interested in the immunologic correlates of disruption and distress under these stressful circumstances.

Sixty-eight employees were examined beginning 11 days post-earthquake and were observed until about 4 months after the earthquake, during which time three psychological and immunologic assessments were done. Subjects experienced life disruption from the earthquake itself, damage to home and possessions, injury to self and others, and damage to and functional disruption of workplace. Questionnaires assessed degree of life disruption (personal and work-related), mood, earthquake-specific distress, and repression (alexithymia, coping style or "Type C", and "immunosuppression-prone" traits). Immune measures included lymphocyte subsets-total T (CD3+), helper T (CD4+), cytotoxic T (CD3 + CD8+), B (CD19+), and natural killer (NK; CD3 - CD16 + CD56+)-as well as lymphoid cell mitogenesis (PHA and PWM), and NK cell cytotoxicity.

Along with a lessening degree of distress over time, a number of immunologic measures declined over the assessment period (CD3+, CD8+, CD16 + 56+ cells. T cell blastogenesis, and NK cell cytotoxicity). Furthermore, subjects reporting low distress had higher numbers of CD3+ and CD8+ cells and a higher proliferative response to PHA. Those with distress corresponding to life disruption had highest levels of CD3+ and CD8+ cells. Measures of repression did not relate directly to immunity.

These results suggest that appropriateness of psychological reaction to the realistic degree of life stress was least disruptive of an aspect of immunity.