NATURAL-KILLER-CELL ACTIVITY AND LYMPHOCYTE SUBPOPULATIONS DURING DOBUTAMINE INFUSION IN MAN

We have studied the effects of dobutamine on natural killer (NK) cell activity and the distribution of lymphocyte subpopulations in peripheral blood in 16 patients under general anaesthesia. Patients were allocated to receive either dobutamine (n = 9) or isotonic saline (n = 7) for 30 min. There was a significant decrease in the ratio of T-helper/inducer cells (CD4) to T-suppressor/cytotoxic cells (CD8) in all patients after induction of anaesthesia. Dobutamine infusion induced an increase in NK cell activity, accompanied by a selective increase in circulating NK cells. However, compared with preinfusion values, CD4:CD8 cell ratio did not change during and after dobutamine infusion. In the isotonic saline group, NK cell activity and CD4:CD8 cell ratio remained unchanged. These results suggest that dobutamine induced an increase in NK cell activity and alterations in lymphocyte subpopulations.