Glutamine-enriched enteral nutrition increases in vitro interferon-gamma production but does not influence the in vivo specific antibody response to KLH after severe trauma. A prospective, double blind, randomized clinical study

Abstract

<h2>Abstract</h2> <i>Background & Aims</i>: Severe trauma leads to an immune suppression, characterized by a Type 2 T-lymphocyte response, contributing to the susceptibility of infectious complications. Plasma concentrations of glutamine (GLN), the preferred fuel for immunocompetent cells, severely decrease after trauma. Since administering glutamine-enriched enteral nutrition (EN) reduces infectious complications in trauma patients, we compared the effect of glutamine-enriched EN with an isocaloric, isonitrogenous enteral control (Con) feeding, on the Type 1 and 2 T-lymphocyte responses. <i>Methods</i>: Thirty-eight trauma patients (Injury Severity Score >20) were sensitized with Keyhole Limpet Hemocyanin (KLH) within 12h after trauma (17 GLN group). Healthy volunteers served as controls (HV, <i>n</i>=17). In vitro interferon-<i>γ</i> (IFN-<i>γ</i>), IL-4 and IL-10 productions of phytohemagglutinin (PHA)-stimulated PBMCs were determined by ELISA technique. KLH-specific IgG, IgM, IgA, IgG1, IgG2, IgG3, IgG4 and IgE were measured in serum. <i>Results</i>: Both patient groups had a low in vitro (IFN-<i>γ</i>) production of stimulated PBMCs on d1. On d14, the IFN-<i>γ</i> production increased significantly in the glutamine group as compared to the controls. IL-4 production was not different between the groups on day 1 (d1). On d14, IL-4 decreased in the control group as compared to the glutamine group. KLH-specific antibodies reached comparable levels in both patients groups and healthy volunteers at d14. <i>Conclusions</i>: In conclusion, trauma caused a suppressed in vitro cellular immune response presented by a low IFN-<i>γ</i> production and depressed the IgG and IgM response to KLH directly after trauma. Glutamine increased IFN-<i>γ</i> production (d14), maintained a normal IL-4 production, but was not acquired for the development of KLH-specific humoral response on d14, in sync suggesting that dietary glutamine supports the restoration of the Type-1 T-lymphocyte responsiveness.