Mechanisms of changes in lymphocyte numbers after psychological stress

In the field of psychoneuroimmunology it has become obvious that the immune system is governed by multiple influences from the central nervous system. One approach to verify these interactions can be seen in stress research. While the phenomenon of stress-induced changes in immunological processes i s widely accepted, more recent studies focus on possible moderators and mec hanisms of these responses. Within this research strategy it became evident that catecholamine increases upon stress are of major importance for the f requently observed mild leukocytosis. The present study was conducted to in vestigate whether the often observed stress-induced increases in the number of peripheral lymphocyte subsets depends on the amount of epinephrine or n orepinephrine release. Moreover, the question was addressed whether high or low catecholamine release is related to subjective ratings on discomfort. Using a "public speaking paradigm", we were able to replicate previous find ings of high increases in the absolute number of CD8+ and CD56+ cells in pe ripheral blood. Moreover, when dividing subjects into high and low catechol amine responders, the amount of change was significantly larger in catechol amine responders irrespective of whether norepinephrine or epinephrine was used for grouping the subjects. However, high and low catecholamine respond ers did not differ with respect to subjective ratings on discomfort. The da ta are discussed with respect to underlying mechanisms in catecholamine-ind uced lymphocyte migration and possible reasons for the mismatch between obj ective and subjective indicators of stressor efficacy.