Disease of the immune system - Rejection of transplants
6 important questions on Disease of the immune system - Rejection of transplants
What is the major antigenic differences between a donor and recipient that result in rejection of transplants
What is characteristic of hyperacute graft rejection?
- mediated by pre-existing antibodies against graft antigens. complement activation within graft blood vessels is induced (inflammation, fibrosis and tissue necrosis)
- Can cause: thrombosis, ischemic damage, and rapid graft failure
- Not common, because donor and recipient are matched before transplantation
- hours-days
What is characteristic of acute graft rejection (cellular)?
- mediated by T cells (cellular rejection)
- CD8+ T cells kill graft cells directly and/or
- CD4+ T cells induce inflammation by cytokine production or macrophage/neutrophil recruitment
- Main cause of early graft failure – immunosuppressive therapy usually successful
- Morphology:
- 1) interstitial inflammation of tissue,
- 2) vascular inflammation or necrosis of vessel walls
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What is characteristic of acute graft rejection (humoral)?
- Antibodies against alloantigens bind to vascular endothelium, triggering classical complement activation, inflammation and tissue damage
- Morphology: inflammation of small blood vessels, associated with deposition of complement factors
What is characteristic of chronic graft rejection?
- Chronic secretion of pro-inflammatory cytokines activates proliferation and activation of fibroblasts and smooth muscle cells
- Morphology: Interstitial tissue fibrosis, narrowing of blood vessels and thickening of vessel walls
- Slow progressive loss of graft function - No successful therapies
- after months
What is Graft-versus-Host Disease (GvHD) and give an example of transplantation that can cause this
- Cells of the graft s recognize alloantigens in the host and attack host tissues and reject the host. It can be acute or chronic.
- Hematopoietic Stem Cell (HSC) Transplantation. Transplantation of multipotent stem cells, usually derived from bone marrow or umbilical cord blood
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