Proinflammatory cytokine production by mitogen-stimulated peripheral bloodmononuclear cells (PBMCs) in trauma patients fed immune-enhancing enteral diets

Widespread metabolic changes associated with injury facilitate the delivery of nutrients to the immune system. The effect of specific nutrients admini stered by the enteral route on the immune response in trauma victims is not well understood. The purpose of this study was to examine whether the synt hesis of proinflammatory cytokines (tumor necrosis factor-alpha [TNF-alpha] , interleukin-1 beta [IL-1 beta], and interleukin-6 [IL-6]) by peripheral b lood mononuclear cells (PBMCs) are influenced by the nature of the dietary fat in critically injured trauma victims. We measured plasma TNF-alpha, IL- 1 beta, and IL-6 and their release stimulated by phytohemagglutinin (PHA) a nd endotoxin (lipopolysaccharide, LPS) from PBMCs of 13 severely injured (i njury severity score = 30 +/- 2) patients once within 48-60 h after injury and then after 7 d of enteral feeding (1.5 g protein[P] . kg(-1) . d(-1)). Group I (n = 6) received diet A (Crucial) and group II (n = 7) received die t B (Impact). The plasma levels of TNP-alpha and IL-1 beta in trauma patien ts are not significantly different from those in healthy volunteers, but pl asma IL-6 levels are significantly increased (five times) in severely injur ed patients. Stimulation of TNF-alpha and IL-1 beta secretion by LPS and PH A were significantly higher in patients than in control subjects; in contra st, there was no stimulation of IL-6 because of trauma or nutritional suppo rt by either of the diets. Stimulation of IL-1 beta by LPS was normalized b y Crucial but was further enhanced by Impact. The higher fat content in Cru cial may contribute in part to the apparent immunomodulation. Crucial seems to be a better choice in correcting the nutritional deficiency. (C) Elsevi er Science Inc. 1999.