Article
Monocyte-dependent suppression of T-cell function following surgical trauma in humans
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Published: | April 26, 2013 |
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Introduction: Surgical trauma and haemorrhage lead to inflammation and postoperative immunosuppression. Previous studies have shown a T-cell dependent suppression of MHC II expression and other functions of antigen presenting cells.
Material and methods: In this study we examined postoperative immunosuppression in human abdominal surgery patients (n = 12) by separating T-cells and monocytes pre-operatively as well as 24 hrs postoperatively using magnetic beads and then co-incubating these cells with naïve preoperative cells of the other cell type, respectively. Following stimulation of postoperative T-cells with anti-CD3 and anti-CD28, cytokine secretion from the naïve monocytes cells was measured in supernatants by a multiplex immunoassay, serving as a bioassay for the functioning of the stimulating postoperative cell T-cell. Similarly, monocyte function was evaluated after stimulation with LPS by measuring cytokine secretion from co-cultured T-cells.
Results: Co-incubation of naïve T-cells with postoperative monocytes and stimulation with LPS lead to a decreased secretion of T-cell cytokines IL-2 (-17%; P = 0.570), IL-10 (-33%; P = 0.010) and IFN-γ (P = 0.002) as compared to coincubation with preoperative monocytes. Expression of monocyte cytokines IL-1β (+24%; P = 0.938), IL-6 (+107%; P = 0.102) and TNF-α(+47%; P = 0.083) was maintained or increased after co-incubation with postoperative T-cells and stimulation with anit-CD3 and anti-CD28. These results were confirmed by co-incubation of postoperative cells with naïve cells from a healthy voluntary donor. Figure 1 [Fig. 1].
Conclusion: Contrary to previous experiments, we observed postoperative T-cells to be able to stimulate monocyte function while postoperative monocytes were defective and could not induce the secretion of cytokines from T-cells. This may be part of the explanation for inadequate immune responses to infection (as a “second hit”) following surgical trauma as a first hit.