Age alone should not be a contraindication for liver resection. However, elderly patients who develop pneumonia are at high risk for postoperative mortality. Therefore, factors such as short time of invasive ventilation, direct and intensive respiratory therapy and mobilization are of particular importance and should be focused on even more.

Acute cellular (CLR) and humoral liver allograft rejection (HLR) are the most important immunological obstacles to successful liver transplantation. In HLR, serum antibodies play the central pathogenetic role. In CLR, CD3+ T lymphocytes drive the destructive immune response. Although CLR and HLR show different clinical symptoms and can be kept apart in most cases, they share histomorphological similarities. In CLR, hepatic B lymphocytes and plasma cells as well as B-cell-activating cytokines have recently been described, indicating that, in addition to T cells, antibody-mediated mechanisms might be involved. To analyze the impact of hepatic B cells in CLR and HLR, the immunoglobulin (Ig) variable (V)-region gene repertoire was determined from tissue of one case of CLR and one case of HLR. Complement deposits and lymphocytic infiltrate were determined using immunohistochemistry. T cells, B lymphocytes and plasma cells could be detected in both cases, whereas C3c and C4d deposits could only be demonstrated in the HLR case. The molecular analysis of 63 V-region genes showed that B cells in both allografts expressed selected V-gene repertoires. All sequences differed from the putative germline sequences by multiple somatic mutations. This suggests a clonal expansion of selected effector B cells in the portal tracts of liver allografts. Locally accumulated B cells and their antibodies might be involved in IgG-mediated complement activation in CLR and HLR.

These results suggest that the type of intraabdominal operation (colon or liver) may influence the degree of trauma of an operation more than the type of technique (laparoscopic or open). The perioperative alteration of stress and immune function has no implications on the long-term results, such as survival time or recurrence, neither in the curative nor in the palliative setting. The thesis that laparoscopic surgery results in less pain, which in turn means less stress and less alteration of the immune system and therefore results in a lower rate of postoperative metastasis is only valid for laparoscopic colonic resection in our model. The part of the thesis that states that fewer metastases should occur after laparoscopic oncological surgery cannot be confirmed in our study.

The results of this study suggest a suppressive effect of helium pneumoperitoneum on postoperative tumor growth and metastatic spread. Furthermore, tumor exposure to room air appears to have a stimulative influence on tumor recurrence and metastasis compared to a pneumoperitoneum established with CO2.

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