FAT EMULSION ADVERSELY AFFECTS LYMPHOCYTE REACTIVITY

Abstract

Although nutritional repletion of malnourished individuals may improve tests of cell-mediated immunity, the effects of intravenous nutrient solutions themselves on the immune system are largely unknown. This study examined the effects of five parenteral nutrition solutions on in vitro lymphocyte reactivity and measured lymphocyte responsiveness in patients receiving parenteral nutrition. Normal human lymphocytes were incubated with dilutions of an amino acid/dextrose solution, an amino acid/dextrose/fat solution, an amino acid solution, dextrose, and a fat emulsion, and lymphocyte responsiveness to antigenic (PPD) and mitogenic (PHA) stimulation was measured using an in vitro electrophoretic test of cell-mediated immunity. Lymphocyte reactivity was measured in 15 postoperative patients allocated randomly to receive either simple electrolyte solutions or isocaloric parenteral regimes with or without a fat emulsion. In vitro lymphocyte responses were significantly depressed (P less than 0.001) by the fat emulsion at concentrations similar to those achieved in clinical practice but were unaffected by dextrose or amino acid solutions. Lymphocyte reactivity was significantly depressed in patients during infusion of the fat emulsion in comparison with controls (P less than 0.05). The results show that fat emulsion impairs lymphocyte reactivity and suggest that careful consideration should be given before using fat emulsions in patients in whom cell-mediated immunity is impaired already.