Histopathology of Kidney Xenograft Rejection

The morphological and immunological changes developing in the renal graft, evaluated qualitatively as well as quantitatively, depend on the genetic relationship between donor and recipient. Based on the genetic differences, five transplantation systems can be defined: 1. Isogeneic. Tissue transplanted from one individual to another individual with an identical genetic constitution (monovular twins) 2. Autogeneic. Tissue transplanted from one place to another in the same individual 3. Allogeneic. Tissue transplanted from one individual to another of the same species 4. Xenogeneic (concordant). Tissue transplanted to an individual of a closely related species (e.g., chimpanze to man) 5. Xenogeneic (discordant). Tissue transplanted to an individual of a distantly related species (e.g., pig to man)