Transplantation Flashcards
3 aims of transplant
Restore physiological function
Not cause recipient harm
Not be rejected
Major problem with immunosuppressants?
Not selective
What type of immune response is hyper acute rejection?
Type II = antibodies at the surface
What are the causes of hyper acute rejection? How does it cause reaction?
ABO/HLA mismatch
IgG binds to non-self antigens on the surface of the transplant and activates complement = inflammation dn destruction
How can number of anti-HLA antibodies increase?
How does this effect rejection?
Pregnancy, previous transplant, multiple blood transfusions
High risk of rejection
What type of immune response is acute rejection?
IV = T cell mediated
What are the 2 types of acute rejection?
Transplant rejection = own alloreactive T cells attach to transplant
HLA = alloantigen
Graft vs host disease = transplanted alloreactive T cells react to own tissue
Alloantigen
Antigens that vary in individuals of same species
What 2 things must be limited in preparation for transplant?
Ischaemia
HLA mismatch
If MHC is mismatched what type of alloreactive CD4+ T cells reactive to, what does this cause?
MHC II
Acute rejection
What does an acutely rejected organ look like?
Red areas of haemorrhage
Grey areas of necrosis
Swelling
What type fo immune response is chronic rejection?
Type III = immune complex
What froms the immune complex in rejection?
Alloantibodies (donor specific) and HLA (an alloantigen)
What does type III rejection cause?
Arteriosclerosis of graft = hyper perfusion, fibrosis and LOF
Why do different organs have different sensitivity to HLA mismatch?
Depends on their expression of HLA
Cornea = low sensitivity = low level of expression = don’t want an immune response in the eye
Bone marrow = high sensitivity as lots expressed (especially MHC II)
