Activity of Natural Killer Cells after Postoperative Amino Acid Infusion

ABSTRACT. Effects of postoperative infusion of a 3 % amino acid solution on natural killer (NK) cell activity were studied in 10 patients undergoing major abdominal surgery. Eight additional patients formed the control group. Preoperative NK cell activity against K562 target cells determined in a short-term 51Cr release assay was similar in patients of both groups. After the operation, in general the patients of both groups showed a decrease in NK cell activity (p< 0.01) but without differences between the groups. There were no changes in the percentages of Leu-7 positive cells (NK cells) between or within the two groups. However, the number of Leu-7 positive cells in blood was lower in the amino acid than in the control group patients during the postoperative days 3-7 (p < 0.05 and 0.01). In vitro, the amino acid solution proved to be nontoxic both for effector and target cells and no depression of NK cel