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Background and aims Abdominal aortic calcification (AAC) was reported as a poor prognostic factor among liver transplantation. However, donor AAC is not enough discussed. We analyzed the impact of the donor AAC level on graft function on outcomes following living donor liver transplantation (LDLT). A total of 133 consecutive patients who had undergone LDLT were divided into two groups (non-AAC group and AAC group) according to their donor AAC level by plain computed tomography. Results The rate of postoperative biliary complications (BC) was significantly higher in AAC group (N=17) than in non-AAC group (N=116) (HR, 2.77; 95% CI, 1.32-5.83; p=.0008). The Cox proportional-hazards regression model revealed that donor AAC (HR, 4.15; 95% CI, 1.93-8.97; p = .0003) and right lobe graft (HR, 2.81; 95% CI, 1.41-5.61; p=.003) increased the risk of BC. Conversely, splenectomy (HR, 0.39; 95% CI, 0.16-0.92; p=.03) decreased the risk of BC after LDLT independently. The long-term survival was also significantly worse in AAC group than in non-AAC group. (HR, 2.25; 95% CI, 1.04-4.89; p=.04) CONCLUSION: Donor AAC was an independent prognostic factor for BC among patients undergoing LDLT. Although further investigations are needed to verify our results, the levels of donor AAC could be a useful tool to identify the risks of BC, and predict better outcomes following LDLT.

The liver exhibits intrinsic immune regulatory properties that maintain tolerance to endogenous and exogenous antigens, and provide protection against pathogens. Such an immune privilege contributes to susceptibility to spontaneous acceptance despite major histocompatibility complex mismatch when transplanted in animal models. Furthermore, the presence of a liver allograft can suppress the rejection of other solid tissue/organ grafts from the same donor. Despite this immune privilege of the livers, to control the undesired alloimmune responses in humans, most liver transplant recipients require long-term treatment with immune-suppressive drugs that predispose to cardiometabolic side effects and renal insufficiency. Understanding the mechanism of liver transplant tolerance and crosstalk between a variety of hepatic immune cells, such as dendritic cells, Kupffer cells, liver sinusoidas endothelial cells, hepatic stellate cells and so on, and alloreactive T cells would lead to the development of strategies for deliberate induction of more specific immune tolerance in a clinical setting. In this review article, we focus on results derived from basic studies that have attempted to elucidate the immune modulatory mechanisms of liver constituent cells and clinical trials that induced immune tolerance after liver transplantation by utilizing the immune-privilege potential of the liver.

Summary Currently, patients are prescribed lifelong treatment with hepatitis B immunoglobulin (HBIg) after liver transplantation (LT) for hepatitis B virus (HBV)-related diseases in order to prevent reinfection with HBV. Active immunization with an HBV vaccine would be a preferable alternative; however, the immunosuppressive environment in LT recipients is believed to elicit a poor response to vaccination. Minimizing the exposure of the HBV-infected LT recipients to immunosuppressants would be beneficial in inducing adaptive immunity against HBV by vaccination. In this study, in addition to efforts to minimize immunosuppression, prophylaxis with HBV vaccination combined with continuous HBIg administration was performed in 17 LT recipients who had undergone transplantation attributable to HBV-related diseases. During the observation period, the overall response rate to HBV vaccination was 64.7%. The immune status of the recipients was evaluated by a mixed lymphocyte reaction assay in response to allostimulation. Patients showing a donor-specific hyporesponse with a well-maintained response to the third-party stimulus always achieved a sustained immune response to the vaccine, whereas patients showing a hyporesponse to both the donor and the third-party stimulus were unable to do so. Thus, inducing an anti-donor-specific immunosuppressive status by minimizing immunosuppression should enable post-transplant HBV vaccination to be a promising prophylactic strategy.

We have described our experience with arterial reconstruction during living-donor liver transplantation by using Varioscope AF3--a head-mounted surgical binocular system with automatic focusing and continuous zoom magnification from 3.6x to 7.2x. From July 1996 to December 2006, 91 grafts were implanted in 89 living-donor liver transplantation recipients, including two that required retransplantation. For microsurgical reconstruction of the graft hepatic artery, a conventional operating microscope was used in the first 10 transplants and Varioscope, in the subsequent 81. The time required to complete arterial reconstruction while using a conventional operating microscope and Varioscope was 78.6 +/- 44.6 min and 35.5 +/- 15.5 min, respectively. No arterial complications, including hepatic artery thrombosis, occurred in any of the 89 patients during the observation period. In living-donor liver transplantation, successful hepatic artery reconstruction can be safely carried out using Varioscope.