Transplant Flashcards
What is graft rejection?
Graft rejection is an example of where the immune response acts detrimentally to the transplant recipient
Xenograft?
Transfer of tissue between species
Isograft?
Identical twins
Autograft?
One part of the body to another
Allograft?
Same species, different person
What does syngeneic mean?
Identical twins
What happens to a second skin graft on the same individual?
It is rejected faster than the first
What are the cells responsible for rejection?
T-cells
What are the T cells reacting against?
MHC/HLA molecules
Chromasome for HLA?
6 (short arm)
Where is class 1 HLA expressed?
– Universally expressed
– Cytoplasm derived proteins
– Presents Ag to CD8+ T cells
Where is class II HLA expressed?
– APC, inducible on other cells
– Extracellular derived proteins
– Presents Ag to CD4+ T cells
What are other markers we look for in transplantation?
A1 A2 B27 B8 DR3 DR3
What determines who gets a kidney?
HLA matching
This does not occur for other organs (eg lung)
What are the three types of rejection?
Antibody mediated
Acute
Chronic
When can Antibody mediated rejection take place?
Can be any time (even months or years later)
What are the types of antibody responses in rejection?
Pre formed antibodies - Blood group - MHC Previous - Blood transfusion - Pregnancy - Transplant
What is acute allograft rejection?
Foreign material travels to the lymph nodes where it can activate a T cell mediated response
What is chronic allograft rejection?
Can be both immunological and non-immunological
What is common to all chronic allograft rejection?
Intimal loss → loss of tubules
How do we prevent allograft rejection?
- Matching ABO antigens (not just expressed on erythrocytes)
- Matching MHC alleles
- Immunosuppressive drugs
How do we knock out the immune system?
Knock out the T cell
What drug is used to knock out the immune system?
Cyclosporin - selectively knocks out recently activated T cells
Also use steriods and azathioprine
What is a problem with using cyclosporin?
No longer effective at fighting viruses
What is the action of steroids?
anti-inflammatory effects
Side effects of steroids?
Fluid retention
Hypertension
Susceptibility to infection
What are the steps in the creation of a bioartificial lung?
Take donor lung ↓ Decellularize with detergent ↓ Establish acellular vasculature, airways and alveoli ↓ Seed scaffold with epithelial and endothelial cells ↓ Perfuse and ventilate in bioreactor
Future clinical applications of bioartificial transplants?
Standard organ donor ↓ Decellularize ↓ Reconstitute with the recipient’s own (damaged) lung endothelial and epithelial cells ↓ Transplant
