Effect of oesophagectomy on monocyte-induced apoptosis of peripheral blood T lymphocytes

Abstract

Background: Surgical stress has been reported to induce immunosuppression. The mechanisms giving rise to T-cell dysfunction following surgery are still unclear. The cellular mechanisms behind T-cell dysfunction following surgery were investigated, based on the induction of T-cell apoptosis and downregulation of T-cell signalling molecules. Methods: Peripheral blood T cells were collected and separated before and after surgery in patients who had oesophagectomy, gastrectomy or cholecystectomy, and studied for their ability to produce cytokines, the induction of T-cell apoptosis with terminal deoxynucleotidyl transferase-mediated dUPT-biotin nick end labelling methods, and the expression of T-cell signalling zeta (TCR ζ) molecules with intracellular staining. Results: The increased degree of T-cell apoptosis, downregulation of TCR ζ molecules and impaired cytokine production of T cells were significant on days 1 and 3 after operation in patients who had oesophagectomy, but not after gastrectomy or cholecystectomy. A higher level of T-cell apoptosis was observed in the co-culture with postoperative monocytes than with preoperative monocytes. Conclusion: Peripheral blood T cells obtained after oesophagectomy underwent apoptosis that correlated with the downregulation of TCR ζ molecules. Postoperative monocytes induced by surgical stress were able to mediate the T-cell apoptosis.