Infections have proven to be a substantial cause of morbidity and mortality after allotransplantation. This is owing in large part to the immunosuppressive treatment needed to prevent graft rejection. Interspecies transplantation may require greater levels of immune suppression than are currently used for allotransplantation, thereby further increasing the risk of opportunistic infection. An additional risk [...]
Xenotransplantation is potentially a reliable, long term solution to the current donor shortage for allotransplanta- tion. At the same time, it presents a number of complex ethical, social and economic issues that must be resolved before it can be fully implemented. Unlike other areas of clinical medicine, xenotransplantation raises a variety of ethical issues that [...]
Xenografted organs that are not destroyed by HAR or DXR are subject to elicited cellular and/or humoral rejection. In pig to primate transplants, Alexandre et al reversed decreases in graft function by administering immunosuppressive agents. Fryer et al expedited the rejection of guinea pig to rat cardiac xenografts by transferring lymphocytes from presensitized animals. It [...]
If HAR is averted, xenografts are still rejected in days instead of minutes or hours by a process referred to as ‘delayed xenograft rejection’ (DXR), also termed ‘acute vascular xenograft rejection’. This process is characterized pathologically by infiltration of leukocytes (particularly monocytes and natural killer [NK] cells), focal ischemia and diffuse microvascular coagulation. There is [...]
The first immunological barrier to xenotransplantation is hyperacute rejection (HAR), characterized by complement activation leading to widespread thrombosis and interstitial hemorrhage of the donor organ. This phenomenon is initiated by the binding of antibodies of the recipient to the vascular endothelium of the donor organ. These naturally occurring ‘xenoreactive’ antibodies (XRAs) recognize cells from discordant [...]
Xenotransplantation: A potential solution to the critical organ donor shortage Orthotopic liver transplantation is the treatment of choice for many patients with end-stage liver disease. Advances in immunosuppression and perioperative care have resulted in a dramatic improvement in survival of patients undergoing liver transplantation. However, the need for donor organs far outweighs the available supply [...]
