Prospective randomized trial demonstrates that postoperative administration of glycyl‐glutamine alleviates the reduction in human leucocyte antigen DR expression on human monocytes induced by surgery

Background The surface expression of major histocompatibility complex class II antigens (human leucocyte antigen (HLA) DR) on monocytes is a major indicator of the immunocompetence of these cells. Surgery, trauma and inflammation lead to a reduction in HLA‐DR expression on monocytes, which is associated with an increased susceptibility to infection and sepsis. The authors have shown surface expression of HLA‐DR on human monocytes in vitro. Following trauma or surgery, glutamine synthesis and secretion from skeletal muscle is increased; intracellular concentrations of glutamine, however, are significantly decreased. It was therefore hypothesized that postoperative infusion of glutamine dipeptides might prevent the decrease in HLA‐DR expression on monocytes. Methods Thirty patients undergoing major abdominal surgery were allocated randomly to receive either 1500 ml Vamin (an amino acid solution containing no glutamine) (controls) or an isonitrogenic formulation containing Vamin and glycyl‐glutamine (35 g glutamine) (GLY‐GLN) or Vamin and alanyl‐glutamine (35 g glutamine) (ALA‐GLN) as a continuous infusion over 48 h after operation. The operations performed included oesophagectomy (three), gastrectomy (four), partial pancreatoduodenectomy (ten), hemihepatectomy (one) and drainage surgery of the biliary/pancreatic duct (ten). Immediately after the operation and 48 h later blood samples were collected for determination of HLA‐DR expression of monocytes in vitro by flow cytometry. Results The groups were comparable with respect to age, sex distribution and operating time. In the GLY‐GLN group mean HLA‐DR expression of monocytes at 48 h was significantly better preserved than in controls.Group n HLA‐DR (MCF) Postop. 48 h % postop.Controls 10 21·0(3) 8·4(1) 42·5(4) ALA‐GLN 10 19·7(3) 9·1(3) 46·5(12) GLY‐GLN 10 19·2(3) 12·0(2) 65·0(7) *Values are mean(s.e.m.). MCF, mean channel fluorescence. * P = 0·04 versus control (Kruskal–Wallis test)Conclusion: Postoperative infusion of GLY‐GLN alleviates the immunosuppression induced by surgery. GLY‐GLN may be superior to ALA‐GLN because of the distinct immunological effect of glycine and alanine. The observed GLY‐GLN‐specific preservation of HLA‐DR on monocytes following surgery may contribute to the prevention of infectious complications in patients undergoing major abdominal surgery. © 2000 British Journal of Surgery Society Ltd