lecture 33 Flashcards
check on learning
the process of taking tissue from one individual and placing them into a different individual
Graft
the individual who provides the graft
Donor
the individual who receives the graft
Recipient
a graft placed into its normal anatomic location like when the skin (thigh to face) from one part is placed in another part
Orthotopic
a graft placed into a different site than normal, like a kidney
Heterotopic
the transfer of circulating blood cells or plasma from one individual to another
Blood transfusion
same individuals like skin graft, vascular grafts
Autograft
between genetically identical individuals, inbred animals or monozygotic twins
Isograft
between allogenic individuals of the same species like friends
Allograft
process of reactivity towards alloantigens or allograft
Alloreactive
between different species
Xenograft
antigens that elicit xenoreactivity
Xenoantigens
process of reactivity towards xenoantigens
Xenoreactive
antigens that are different between the donor and recipient, these are polymorphic proteins and are reacted against by T lymphocytes
Alloantigens
proteins that elicit alloreaction and result in incompatibility
Histocompatibility antigens
antigens that are very strong or dominant in eliciting the rejection reaction
Major histocompatibility antigens
genes that encode the major histocompatibility antigens
Major histocompatibility complex
weaker antigens that induce a slower more gradual rejection
Minor histocompatibility antigens
highly polymorphic, inherited, carbohydrate or protein structure located on the surface of the RBC membrane
Blood group antigens
a test used for tissue matching that involves beads coated with a defined MHC molecule, representative of the organ donor; if binding, it’s a no go
Panel reactive antibody test
tissue matching test that determines if the patient has antibodies that react with donor’s cells; positive lysis indicates antibodies present and not recommended; cornea and liver does not need HLA matching
Cross matching test
recipient T cells recognize intact, unprocessed MHC molecules in the graft
Direct presentation
MHC molecules of the donor, allogenic, are captured and processed by the recipient APCs and peptides of the MHC are presented with self MHCs
Indirect presentation
preformed antibodies reactive with vascular endothelium activate complement and trigger rapid intravascular thrombosis and necrosis of the vessel wall; begins within minutes
Hyperacute graft rejection
a type of graft rejection mediated by an adaptive immune response, begins days to weeks, mediated by T cells that are reactive with alloantigens on endothelial cells in blood vessels and parenchymal cells leading to parenchymal cell damage and interstitial inflammation, endothelialitis, inflammatory nitrates and vasculitis
Acute graft rejection (cellular rejection)
a type of graft rejection in which the Alloantibodies cause acute rejection by binding to alloantigens, mainly HLA molecules, on vascular endothelial cells, leading to endothelial injury and intravascular thrombosis that results in graft destruction; endothelitis; inflammatory cells in peritubular capillaries and complement C4d deposition in capillaries.
Acute graft rejection (antibody-mediated rejection)
rejection of graft that takes months to years due to immunosuppressive drugs; damage to vessels, airways, and bile ducts; arterial occlusion results due to proliferation of smooth muscle and ischemic damage can happen
Chronic rejection
proliferation of vascular smooth muscles by cytokines produced by chronically activated T cells
Graft vasculopathy
mature t cells in the graft reject the host
Graft versus host disease (GVHD)
characterized by epithelial cell death in the skin, liver, and GI tract, rich in HLA class I; seen with rash, jaundice, diarrhea and GI hemorrhage
Acute GVHD
characterized by fibrosis and atrophy of one or more of the same organs, without evidence of cell death
Chronic GVHD
grafts from other species, leads to hyperacute rejection and zoonotic disease
Xenotransplantation
when the brain, eye, testes, placenta and fetus are protected to a degree from the immune response
Immune privilege
