Transplant

Question 1

What is a transplant?

Answer 1

replacement of tissues/organs undergone irreversible pathological process which threatens patients life or hampers QOL

Question 2

Transplanted organs

Answer 2

• lungs
• heart
• kidneys
• pancreas
• uterus
• liver

Question 3

Transplanted tissues

Answer 3

skin
nerves
bone marrow
cornea

Question 4

autograft

Answer 4

eg skin graft

Question 5

isograft

Answer 5

eg identical twin

can have different HLA

Question 6

allograft

Answer 6

eg sister - not genetically identical

Question 7

xenograft

Answer 7

eg pig heart valves

Question 8

What chromosome is histocompatibility on?

Answer 8

chromosome 6

Question 9

HLA class 1

Answer 9

HLA - A,B,C
all nucleated cells
Tc

Question 10

HLA class 2

Answer 10

HLA-DR
only APC
CD4, Th
most important in rejection

Question 11

What % of transplant recipients have HLA identical donor?

Answer 11

30%

Question 12

Privileged sites

Answer 12

blood flow = immunity exposed

no immunosuppression, no sensitisation etc

Question 13

When does graft rejection occur?

Answer 13

transplant tissue is rejected by recipients immune system which destroys transplanted tissue

Question 14

Graft rejection causes

Answer 14

ABO or HLA incompatible
sensitisation
failed immunosuppression
infections/enviro triggers

Question 15

Immediate rejection

Answer 15

in minutes, HLA-ABO incompatible
complement activation
inflammation and thrombosis

Question 16

3 phases of sensitisation in acute rejection

Answer 16

recognition - alloantigens
APC reaction - via MHC
co-stimulation via CD28,CD40

Question 17

When does acute rejection occur?

Answer 17

first 6 months

Question 18

Infiltrate in acute rejection

Answer 18

Tc, B cells, NK, macrophages

Question 19

Treatment of rejection

Answer 19

CCS
anti thymocyte globulin
plasma exchange

Question 20

Other complications of transplant

Answer 20

infection
bleeding
malignancy - melanoma, lymphoma
recurrence of original disease

Question 21

Preventing graft rejection

Answer 21

ABO matching
tissue typing - class 1+2 HLA
prophylactic immunosuppression

Question 22

Immunosuppression used

Answer 22

CCS - prednisolone
calcineurin inhibitors eg tacrolimus
anti proliferatives

Question 23

What does graft versus host disease usually occur in?

Answer 23

bone marrow transplant

Question 24

triad for graft vs host disease

Answer 24

immunocompetent cells in graft
defective recipient immunity
HLA differences

Question 25

Preventing graft vs host disease

Answer 25

donor/recipient matching

donor marrow T cell depletion

Question 26

Types of donors

Answer 26

living - related/unrelated, altruistic

dead - DBD,DCD

Question 27

What happens in unmodified xenografts?

Answer 27

hyperacute rejection

Question 28

unmodified xenografts - immunological

Answer 28

natural IgM human anti-swine ab –> graft endothelial galactose residues