Surgical anticipatory stress manifests itself in immunocyte desensitization: Evidence for autoimmunoregulatory involvement

The immunocyte behavior (conformational changes and locomotion in response to signal molecule challenge) in patients about to undergo elective cardiac surgery was studied to elucidate the effect of psychological anticipatory stress on the immune system. Granulocytes and monocytes from 10 patients and 35 non-surgical controls were examined. Computer-assisted microscopic image analysis, capable of measuring cellular conformational and velocity changes, was used to measure the responsiveness of these immunocytes to peptidergic and cytokine stimulation. Immunocyte desensitization would appear to account for the reduction in their abilities to respond to chemotaxic challenge associated with the pre-cardiac surgery state. Their abilities to respond to D-Ala2-Met-enkephalinamide (DAMA) were observed only at much higher concentrations than previously reported (10-11 M vs. 10-9 M prior to surgery). This finding, together with the observed decrease in adrenocorticotropin levels compared to nonsurgical controls, suggests that neutral endopeptidase activity was elevated just prior to surgery. Indeed, neutral endopeptidase activity is statistically elevated in the pre-cardiac surgery state. Furthermore, glucocorticoid levels remained constant, within normal resting limits, in both groups. Thus, surgical anticipatory stress may manifest itself, in part, as a desensitization of various immunocytes. Thus, a psychological anticipatory stress response may be a precipitant of the desensitization. Although this desensitization seemed not to involve the entire hypothalamic-pituitary-adrenal axis, the data suggest that psychological anticipatory stress may initially involve and influence autoimmunoregulation.