Aim: HLA-DR monocyte expression may be affected by major surgery. A potential mechanism for monocyte activation is the engagement of costimulatory receptors (B7-2 or CD-86). The aim of the present study was to determine the possible role of monocyte HLA-DR and B7-2 molecules in the occurrence of postoperative sepsis after major cancer surgery.
Methods: This was an observational study in 25 consecutive patients undergoing major elective surgery. Flow cytometry measures were used to determine the expression of HLA-DR and its costimulatory receptors before (day 0) and after surgery (day 1 and day 2).
Results: After surgery, the rate of monocytes expressing HLA-DR decreased significantly in all the patients. As compared with day 0, the rate of monocytes expressing B7-2 decreased in all the patients (P<0.03). In the septic group, it remained significantly decreased postoperatively. In the non-septic group, it reached baseline levels at day 2.
Conclusion: Results suggest a key role for costimulatory molecules in modulating inflammatory response in the context of subsequent postoperative sepsis after major cancer surgery. These molecules may be involved, in association with HLA-DR, in postoperative monocyte dysfunction.