Major surgical trauma differentially affects T-cells and APC

Area of Science:

• Immunology
• Surgical Pathology

Background:

• Trauma and hemorrhage are known to induce immunosuppression, with macrophages initiating this response.
• Emerging research indicates T-cells are crucial in sustaining immunosuppression post-injury.

Purpose of the Study:

• To examine the interaction between antigen-presenting cells (APCs) and T-cells in human patients after major surgery.
• To elucidate the functional changes in APCs and T-cells and their interplay in the postoperative immune response.

Main Methods:

• Isolation and characterization of APCs and T-cells from 14 surgical patients at 2 and 24 hours postoperatively.
• Co-incubation of pre-operative and post-operative APCs and T-cells.
• Measurement of chemokine secretion (TNF-α, IL-6, IFN-γ) via enzyme immunoassay as a functional readout.

Main Results:

• Postoperative suppression of CD3(+) T-cells and CD28, while regulatory T-cells (Tregs) remained unaffected.
• Increased counts of CD14(+) APCs, particularly CD14(+)HLA-DR(-) myeloid-derived suppressor cells.
• APCs exhibited elevated TNF-α and IL-6 secretion post-surgery. T-cells co-incubated with APCs showed reduced IFN-γ secretion.

Conclusions:

• T-cells are pivotal in mediating immunosuppression after major abdominal surgery.
• The interaction between APCs and T-cells significantly impacts the postoperative immune status.