Immunology - transplantation

Question 1

What is rejection?

Answer 1

Damage done by the immune system to a transplanted organ

Question 2

What is an autologous transplant?

Answer 2

Tissue returning to the same individual after a period outside the body, usually in a frozen state

Question 3

What is syngeneic transplant (also called isograft)?

Answer 3

Transplant between identical twins. Usually no problem with rejection

Question 4

What is allogeneic transplant?

Answer 4

Takes place between genetically nonidentical members of the same species - always a risk of rejection

Question 5

What is cadaveric transplantation?

Answer 5

Use organs from a dead donor

Question 6

What is xenogeneic transplant?

Answer 6

Takes place between different species. Highest risk of rejection

Question 7

What are criteria for solid organ transplantation?

Answer 7

Good evidence that damage is irreversible
Alternative treatments are not applicable
Disease must not recur

Question 8

What are examples of organs that can be transplanted?

Answer 8

Heart - heart failure
Lung transplant
Liver
Pancreas
Kidney

Question 9

How can we reduce risk of transplant rejection?

Answer 9

Donor and recipient must be ABO compatible
Recipient must not have anti-donor human leukocyte antigen antibodies
Donor should be selected with close as possible humon leukocyte antigen match to recipient
Patient must take immunosuppressive drugs

Question 10

What is hyperacute rejection?

Answer 10

Within hours of transplantation, preformed antibodies bind to either ABO blood group or HLA class I antigens on graft. Triggers a type II hypersensitivity response and graft is destroyed through vascular thrombosis

Question 11

How is hyperacute rejection prevented?

Answer 11

Careful ABO and HLA cross-matching

Question 12

What is acute rejection?

Answer 12

Donor dendritic cells stimulate allogeneic response in a local lymph node, T cells proliferate and migrate to donor organ

Question 13

How long does acute rejection take to happen?

Answer 13

Within days or weeks of transplant

Question 14

What type of hypersensitivity reaction is acute rejection?

Answer 14

Type IV

Question 15

What is chronic rejection?

Answer 15

Element of allogeneic reaction mediated by T cells, results in repeated acute rejection

Question 16

What can cause chronic rejection?

Answer 16

Pre-existing autoimmune disease

Question 17

How long does chronic rejection take to occur?

Answer 17

Months or years after transplant

Question 18

What is graft versus host disease?

Answer 18

Donor T cells respond to allogeneic recipient antigens, common in stem cell transplant but also happens in solid organ transplant

Question 19

How long does acute GVHD take to occur?

Answer 19

Up to 4 weeks after stem cell transplant

Question 20

What immunosuppresive drugs can be used after transplant?

Answer 20

Corticosteroids - low maintenance dose, high dose to treat rejection
T-cell signalling blockade
IL-2 blockade
Antiproliferatives

Question 21

What drugs are used on T-cell signalling blockade?

Answer 21

Cyclosporine

Tacrolimus

Question 22

What drugs are used in IL-2 blockade?

Answer 22

Monoclonal antibodies against IL-2 receptor - basiliximab - used for acute graft rejection
Rapamycin - maintenance drug to prevent rejection

Question 23

What antiproliferative drugs are used for immunosuppression?

Answer 23

Azathioprine
Mycophenolate
Mofetil
Methotrexate

Question 24

What are side effects of cyclosporin?

Answer 24

Recurrent viral, bacterial and fungal INFECTIONS
Increased risk of certain CANCERS
NEPHROTOXIC properties
Diabetes
Hypertension

Question 25

What are side effects of rapamycin?

Answer 25

Raised lipid and chiolesterol levels
Hypertension
Anaemia
Diarrhoea
Rash
Acne
Thrombocytopenia
Decreases in platelets and haemoglobin