Transplantation

Question 1

What is an allograft (most common type) and what must you do to prevent rejection

Answer 1

Transplant from genetically non-identical member of same species
Have to tissue match to prevent rejection

Question 2

What is an isograft

Answer 2

Transplant from identical twin

Still requires immunosuppression as exposed to different antigens throughout life so different Ab’s

Question 3

What is an autograft

Answer 3

Transplant between different sites on same organism

Skin graft or buccal urethrostomy

Question 4

What is an xenograft

Answer 4

Transplant from different species e.g. heart valves

Question 5

What will an unmodified xenograft lead to

Answer 5

Hyperacute rejection as humans have natural IgM anti swine Ab and pigs don’t have HLA

Question 6

How do you prevent rejection in xenograft

Answer 6

Remove IGM
Genetically modify pigs
Humanised transgenic pigs

Question 7

What are privelledged sites

Answer 7

Little blood or lymphatic supply e.g. cornea

No tissue matching or immune suppression needed

Question 8

What are complications of transplantation

Answer 8

Rejection 
Bleeding 
Wound infection
Vacular thrombosis
New onset DM
Infections
Electrolyte / fluid disturbance
Malignancy - post transplant lymphoma / SCC
Drug SE
Recurrence of original disease

Question 9

What causes rejection

Answer 9

ABO or HLA incompatible
Preformed immunity from previous transplant / pregnancy / blood transfusion (sensitisation)
Failed immunosuppression or non-compliance = most common
Infections
Environment

Question 10

How do you prevent rejection

What is most important

Answer 10

ABO matching - need exact match or get immediate reaction
Tissue typing - HLA doesn’t need to be perfect but ensures longer graft
HLA Class 2 most important - HLA-DR
HLA - A and B of class 1 also important
Prophylactic immunosuppression

Question 11

What is given prophylactic as immunosuppression as long as transplant in

Answer 11

Corticosteroid
Tacrolimus - calcineurin inhibitor that blocks IL-2 which is released in any inflammation
MMF.- anti-proliferative of lymphocytes

Question 12

What happens in hyperacute rejection

Answer 12

Organ won’t perfuse
Usually due to ABO / HLA mismatch - preformed Ab in blood so quick
Activates innate immune so hard to stop

Question 13

What increases risk of hyperacute

Answer 13

Previous transplant
Pregnancy
Blood transfusion

Question 14

What causes acute rejection <6 months

Answer 14

Cell + Ab mediated (Innate)
T cell recognise allo-MHC and attack
Inflammation and parenchymal damage of organ
Can lead to chronic

Question 15

What is the treatment for acute rejection

Answer 15

Aggressive immunosuppression

Question 16

What is chronic rejection

Answer 16

Most common cause 
>6 months 
Chronic inflammation to alloantigens
Ab mediated with other innate components 
Can't fix once started

Question 17

How do you treat rejection

Answer 17

IV steroid and oral corticosteroid in high dose
Anti-thymocyte globulin
IV Ig
Plasma exchanhe

Question 18

What is required in GVHD

Answer 18

Immunocompotent cells in graft
Immunocompromised host
HLA mismatch between donor and recipient

Question 19

How do you prevent GVHD

Answer 19

Donor T cell depletion / leucocyte depletion

Matching

Question 20

What are types of donation

Answer 20

Living - related, unrelated, altruistic

Deceased - brain death (DBD), cadaveric death (DCD)

Question 21

What does GVHD cause

Answer 21

Catastrophic reaction as graft destroys ever tissue in body

Question 22

What is best type of donation

Answer 22

Living related