Postoperative glycyl-glutamine infusion reduces immunosuppression: partialprevention of the surgery induced decrease in HLA-DR expression on monocytes

Background and aims: Surgery, trauma and inflammation reduce HLA-DR express ion on monocytes, which is associated with an increased susceptibility to i nfection and sepsis. Furthermore, surgery decreases plasma glutamine (GLN) levels. The expression of HLA-DR on human monocytes in vitro is dependent o n the concentration of GLN in the culture medium. We therefore hypothesized that postoperative infusions of glutamine-dipeptides would prevent the dec reased HLA-DR expression on monocytes. Methods. Thirty patients undergoing major abdominal surgery were randomly a llocated to receive either 1500 ml Vamin (control) or an isonitrogenic form ulation containing Vamin and 500 ml glycyl-glutamine (35 g GLN; 0.5g/kg BW) (GLY-GLN), or Vamin and 500 ml alanyl-glutamine (35 g GLN; 0.5 g/kg BW) (A LA-GLN) as a continuous infusion over 48 h post-operatively. Immediately an d 48 h after surgery blood samples were collected to determine HLA-DR expre ssion on monocytes by flow cytometry. Results: The groups were comparable with respect to age, gender distributio n and operation time. In patients receiving GLY-GLN mean HLA-DR expression on monocytes at 48 h was significantly better preserved than in controls (6 5.0 % +/- 7 % vs 42.5 % +/- 4 %; P < 0.05), whereas HLA-DR expression on mo nocytes in patients reveiving ALA-GLN was not significantly different. Conclusion: This is the first study comparing the dipeptides GLY-GLN and AL A-GLN in the postoperative setting. The GLY-GLN induced preservation of HLA -DR on monocytes following surgery may prevent infectious complications in these patients. (C) 2000 Harcourt Publishers Ltd.