Organ Transplantation Flashcards
An isograft refers to _
Transplantation between identical twin
An autograft refers to _
Transplantation from a person back to same person
An allograft refers to _
Transplantation between non-identical members of same species
A xenograft refers to _
Transplantation between species
Tissue rejection that occurs with in 24 hrs is _. This requires _ to mediate it
Hyperacute rejection
Already circulating antibody
What type of rejection would you expect if an animal organ is transplanted into a human? Why?
Hyper acute rejection
The antibodies against other organisms are already present
Complement activation, endothelial damage, inflammation and thrombosis are all characteristics of _
Hyperacute rejection
Organ rejection that occurs 7 days to 6 months after transplant is _. What are the mediating cells?
Acute rejection
T cells and B cells
Majority of transplants are lost as a result of _.
Chronic rejection
What is chronic rejection? What are the hall marks?
When a patient eventually develops antibodies against a graft, this causes chronic inflammation in the vessel wall, and significant thickening of the smooth muscle. (Intima thickening)
A graft being rejected that is inflitrated by PMNs is undergoing what type of rejection?
Acute rejection
What is a mitogen?
Any substance that will cause proliferation
Acute phase reaction is treated by _
T cell blockers (OKT3, thymoglobulin), cause apoptosis
Cyclosporin A, FK506 - blocks T cell signaling
IL2 blocking - required for T cell activation
Rapamycin - block IL2 signaling
HLA mismatch is a way to save patients from immunosuppression. Increased mismatches increases chance of graft failure. True or False
True
What is graft vs host disease? What type of transplant is it most commonly associated with? Why does it occur?
T cells from the graft will reject the recipient
Bone marrow transplants
Treatment of patients to prepare for transplant damages host endothelium, increasing new T cell activation
If a tumor is resected from a mouse, cells expanded and transplanted into the same mouse, what happens? Why?
The tumor is attacked. This is because the mouse develops memory
If a tumor is resected from a mouse, cells expanded and transplanted into the another mouse, what happens? Why?
The tumor grows. The new mouse has no memory
If a tumor is resected from a mouse, cells expanded and transplanted into the another mouse, along with T cells from the original mouse, what happens? Why?
The tumor doesn’t grow. Because the T-cells with the memory will mount an immune response and kill the tumor
What are 3 ways that tumors evade the immune system?
Enzymatic down regulation of T cells
Down regulation of tumor MHC, costim molecules
Failure to produce tumor antigens
What is a proposed mechanism for tumor regression in patients?
Reintroduce patient’s own lymphocytes along with IL2 to fight patient’s tumor
