Human granulocyte and reticuloendothelial system function during intralipid infusion.

In six patients, the phagocytic and catabolic functions of the RES (reticuloendothelial system), as measured by using 125I-microaggregated human serum albumin as a test substance, were not affected by Intralipid infusion. The nitroblue tetrazolium (NBT) reduction of granulocytes, the NBT reduction and the bacplasma, was significantly lower in eight patients during Intralipid infusion than before this treatment. When heat-killed E. coli were added for phagocytic stimulation in vitro, the same result was obtained only in the absence of plasma. The bactericidal capacity of granulocytes was significantly decreased in six patients during Intralipid infusion. When Intralipid was added in vitro to granulocytes, the NBT reduction, and the bactericidal capacity of these cells were decreased and the effect was mainly dose-dependent. Electron micrographs show that granulocytes phagocytize Intralipid. The loading of granulocytes with lipid particles may block the engulfment of bacteria and may be a reason for the decreased bactericidal capacity of these cells. An influence exerted by the lipid on the cell membrane is the most conceivable reason for the decreased NBT reduction.