Search

Introduction: Prolonged immunosuppression has been demonstrated after trauma-hemorrhage resulting in an increased susceptibility to sepsis. The contribution of antigen-presenting cells (APC) vs T cells to this diminished immune response, however, remains unknown., Materials and Methods: To study this, male mice were trauma-hemorrhaged (35 +/- 5 mmHg for 90 min and resuscitation) or sham operated. At 24 h thereafter, spleens were harvested and T cells (via Microbeads) and APC (via adherence) were isolated. Cocultures of combined T cells and APC were established for 48 h, stimulated with ConA and LPS. The T cell-derived cytokine IFN-gamma and IL-12 for APC responses were measured in the supernatants by the multiplex assay., Results: The release of IFN-gamma was suppressed by T cells after trauma-hemorrhage irrespective of whether sham or trauma-hemorrhage APC were added. Trauma-hemorrhaged APC did not affect T cells-derived IFN-gamma release by sham T cells. In contrast, trauma-hemorrhaged T cells depressed the release of IL-12 by APC. The release of IL-12 by trauma-hemorrhaged APC was not altered when sham T cells were cocultured., Conclusion: Prolonged immunosuppression after trauma-hemorrhage appears to be predominantly due to diminished T cell function. Thus, attempts to prevent immunodysfunction should be directed towards T cells.

Following several disappointing approaches to decrease the mortality of septic patients using various adjuncts, protein C is the first substance leading to a significant reduction of the mortality rate (PROWESS). The increased risk for bleeding complications in patients receiving protein C, however, limits its use in septic surgical patients. Administration of AT III in septic patients (KYBERSEPT) reduced the mortality rate solely in patients which were not treated with heparin. Although hydrocortisone reduced the amount of vasoactive katecholamines the effect of hydrocortisone administration on the survival rate remains unknown. In summary, early intervention to eliminate the septic focus and the use of antibiotics according to an antibiogramm still remains the most efficient basis for the treatment of septic patients.

Immunological changes as described in endovascular aortic aneurysm repair are not yet fully understood. In several studies this reaction (leukocytosis, fever, high CRP levels) is named as a "postimplantation syndrome". In our study we could show that in the first week after endovascular aortic aneurysm surgery complex immunological changes occur. But these changes do not quantitatively differ from those seen in open aortic aneurysm surgery. Fever (38 degrees C) was apparent in almost all patients. White blood cell count rose up to 10.6 (+/- 0.84) G/L during the first days. CRP, one of the acute phase proteins, was elevated with the maximum on postoperative day 2. Only the open operated patients had elevated alpha 1-antitrypsin levels from the second postoperative day on. IL-6 synthesis was increased in both groups, with an elevation in group B until day 8. The coagulation system was impaired, but was most evident in the open aortic aneurysm group. In this study we could show that both operative techniques had comparable immunological changes. During open aneurysm repair the large operative trauma seems to play a central role, whereas endothel activation might be crucial in endovascular operated patients.