Organ Transplantation

Question 1

An isograft refers to _

Answer 1

Transplantation between identical twin

Question 2

An autograft refers to _

Answer 2

Transplantation from a person back to same person

Question 3

An allograft refers to _

Answer 3

Transplantation between non-identical members of same species

Question 4

A xenograft refers to _

Answer 4

Transplantation between species

Question 5

Tissue rejection that occurs with in 24 hrs is _. This requires _ to mediate it

Answer 5

Hyperacute rejection

Already circulating antibody

Question 6

What type of rejection would you expect if an animal organ is transplanted into a human? Why?

Answer 6

Hyper acute rejection

The antibodies against other organisms are already present

Question 7

Complement activation, endothelial damage, inflammation and thrombosis are all characteristics of _

Answer 7

Hyperacute rejection

Question 8

Organ rejection that occurs 7 days to 6 months after transplant is _. What are the mediating cells?

Answer 8

Acute rejection

T cells and B cells

Question 9

Majority of transplants are lost as a result of _.

Answer 9

Chronic rejection

Question 10

What is chronic rejection? What are the hall marks?

Answer 10

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)

Question 11

A graft being rejected that is inflitrated by PMNs is undergoing what type of rejection?

Answer 11

Acute rejection

Question 12

What is a mitogen?

Answer 12

Any substance that will cause proliferation

Question 13

Acute phase reaction is treated by _

Answer 13

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

Question 14

HLA mismatch is a way to save patients from immunosuppression. Increased mismatches increases chance of graft failure. True or False

Answer 14

True

Question 15

What is graft vs host disease? What type of transplant is it most commonly associated with? Why does it occur?

Answer 15

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

Question 16

If a tumor is resected from a mouse, cells expanded and transplanted into the same mouse, what happens? Why?

Answer 16

The tumor is attacked. This is because the mouse develops memory

Question 17

If a tumor is resected from a mouse, cells expanded and transplanted into the another mouse, what happens? Why?

Answer 17

The tumor grows. The new mouse has no memory

Question 18

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?

Answer 18

The tumor doesn’t grow. Because the T-cells with the memory will mount an immune response and kill the tumor

Question 19

What are 3 ways that tumors evade the immune system?

Answer 19

Enzymatic down regulation of T cells
Down regulation of tumor MHC, costim molecules
Failure to produce tumor antigens

Question 20

What is a proposed mechanism for tumor regression in patients?

Answer 20

Reintroduce patient’s own lymphocytes along with IL2 to fight patient’s tumor