Chapter 13: Transplantation Flashcards
Autologous grafts? (also other name)
autografts
those where tissue moved from one location to another in same individual (skin grafting in burns for example)
Isografts? (also other name)
syngeneic grafts
those transplanted between geentically identical individuals (monozygotic twins)
Allogeneic grafts.
those transplanted between genetically different members of the same species (kidney transplant)
Xenogenic grafts.
those transplanted between members of different species (pig heart valve into human)
Hyperacute graft rejection time frame?
minutes to hours
What is the pathogenesis of hyperacute graft rejection?
due to pre-formed ab due to transfusions, multi-parity, or previous organ transplants (type II cytotoxic hypersensitivity)
*ab bind to grafted tissue and activate complement and the clotting cascade resulting in thrombosis and ischemic necrosis
Why are hyperacute rejections rare?
cross matching blood
Acute graft rejection time-frame.
within days to weeks; timing and mechanism are similar to a primary immune response
Acute graft rejections are induced by what?
alloantgenns (predominantly MHC) in the graft
What lymphocytes play a role in acute graft rejection?
both CD4 and CD8 T cells play a role as well as antibodies (think normal immune response)
How can you prevent acute graft rejections?
immunosuppressive therapy works to prevent this type of graft rejection mainly
What is the time frame involved with accelerated acute graft rejection?
within days; the timing and mechanism are similar to memory response
What is the time-frame associated with chronic graft rejection?
occurs within months to years
What cells primarily mediated the chronic graft rejection response?
- predominantly T-cell mediated
Etiology of chronic graft rejection?
not well understood, possibly triggered by viral infections
