INFLUENCE OF MINOR INCREASES IN PLASMA-CATECHOLAMINES ON NATURAL-KILLER-CELL ACTIVITY

This study was designed to test the hypothesis that the modulations of the human immune system in relation to in vivo whole body hyperthermi a may be ascribed to elevations in the plasma epinephrine and norepine phrine concentrations. In a single-blind, controlled, cross-over study , 8 healthy volunteers were selectively infused norepinephrine and epi nephrine, respectively, for 1 h, in order to obtain twofold increases in the plasma concentrations of these hormones, thereby mimicking the increases seen during in vivo whole body hyperthermia. Epinephrine inf usion increased baseline, interleukin-2 and interferon-alpha stimulate d natural killer cell activity, and the percentage and concentration o f cluster designation (CD)16+ cells, whereas the neutrophil and lympho cyte count or the CD3+, CD4+, CD8+, CD19+ and CD14+ cell subtypes were not influenced. Norepinephrine infusion did not cause any changes in these variables. It is concluded that epinephrine, but not norepinephr ine, may be responsible for the hyperthermia-induced effects on natura l killer cells.