Surgical stress induces decreased expression of signal-transducing zeta molecules in T cells

Surgical stress is known to induce immunosuppression of T cell functions, b ut the mechanism behind this phenomenon is unclear. The purpose of this stu dy was to determine whether surgical stress affects the expression of signa l-transducing zeta molecules in peripheral T cells. In the present study, t he expression of signal-transducing zeta molecules was studied by flow-cyto metric analysis of permeabilized cells in peripheral blood mononuclear cell s from 28 patients before and after surgery. The results demonstrate that T cell receptor (TCR) zeta levels in the peripheral T cells were lower on th e 2nd or 3rd postoperative days (POD) compared to the preoperative period a nd recovered on the 7th POD in patients who received major surgery. Surface CD3 epsilon levels were also decreased after surgery but did not recover o n the 7th POD. Culturing of T cells from the preoperative period with autol ogous monocytes from the 2nd POD induced a decreased expression of their IC R zeta. The reduction was prevented by the addition of catalase, a selectiv e scavenger of hydrogen peroxide, indicating that this phenomenon was media ted by hydrogen peroxide. These results suggest that the decreased expressi on of TCR zeta molecules in peripheral T cells was induced by surgical stre ss, and was mediated by hydrogen peroxide derived from monocytes.