Mechanisms of intralipid effect on polymorphonuclear leukocytes.

The effect of Intralipid, a lipid emulsion used in total parenteral nutrition, on polymorphonuclear leukocytes (PMNL) was studied in vitro. Preincubation of PMNL with Intralipid was found to depress oxidative metabolic and phagocytic functions. Preincubation of PMNL with intralipid also caused a decrease in Fc receptors. However, when Intralipid was added at the start of metabolic assays, it stimulated the respiratory burst. We interpret these findings as suggesting that Intralipid, acting as a particulate stimulus, activated and exhausted metabolic pathways involved in the respiratory burst and phagocytosis and that it also decreased numbers or availability of Fc receptors on PMNL. Individual components of Intralipid did not induce these changes. This dysfunction may contribute to the infections seen in patients receiving parenteral hyperalimentation with Intralipid supplementation.