Immunological effects of glutamine supplementation in polytrauma patients in intensive care unit

BACKGROUND: In polytrauma intensive care unit (ICU) patients, glutamine (GLN) becomes a “conditionally essential” amino acid; its role has been extensively studied in numerous clinical trials but their results are inconclusive. We evaluated the IgA-mediated humoral immunity after GLN supplementation in polytrauma ICU patients. METHODS: All consecutive patients with polytrauma who required mechanical ventilation and enteral nutrition (EN) provided within 24 h since the admission in ICU at the University Hospital of Foggia from September 2016 to February 2017 were included. Thereafter, two groups were identified: patients treated by conventional EN (25 kcal/kg/die) and patients who have received conventional EN enriched with 50 mg/kg/ideal body weight of alanyl-GLN 20% intravenously. We analysed the plasmatic concentration of IgA, CD3+/CD4+ T helper lymphocytes, CD3+/CD8+ T suppressor lymphocytes, CD3+/CD19+ B lymphocytes, IL-4 and IL-2 at admission and at 4 and 8 days. RESULTS: We identified 30 patients, with 15 subjects per group. IgA levels increased significantly in GLN vs the control group at T0, T4 and T8. CD3+/CD4+ T helper lymphocyte and CD3+/CD8+ T suppressor lymphocyte levels significantly increased in GLN vs the control group at T4 and T8. CD3+/CD19+ B lymphocyte levels increased significantly in GLN vs the control group only at T8. IL-2 and IL-4 levels showed no significant differences when comparing GLN with the control group. CONCLUSIONS: Our study showed that there was an improvement in humoral and cell-mediated immunity with GLN supplementation in polytrauma ICU patients using recommended doses.