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Flashcards in Transplantation Deck (31)
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what is an autograft?

move tissue from one part of the body to another

1

what is an isograft

tissue between genetically identical identicals

2

what is an allograft?

tissue transplantation between different members of the same species

3

what is a xenograft?

transplantation between members of different species

4

what is the cell responsible for transplant rejection and how?

T cells - recognise non-self antigens presented on MHC complexes

5

which chromosome is the MHC located on?

short arm of chromosome 6

6

which cells do the class 1 and class 2 MHC presenting to

1 - CD8 T cells
2 - CD4 T cells

7

what is the major transplant antigen

MHC molecules

8

what are the most important alleles on the MHC to match for transplantation

A, B and DR

9

graft survival of a solid organ transplant is directly related to

HLA matching

10

what is the dose response relationship with HLA mismatching

the more mismatches.... the worsening of long term graft survival

11

why arent lung and heart transplants HLA matches?

due to urgency

12

types of transplantation rejection and their timing

hyperacute - minutes-hours
acute - days-weeks
chronic - months-years

13

what is the cause of hyperacute rejection

preformed anti-donor antibodies and complement

14

what is the cause of acute transplant rejection

primary activation of T cells

15

what is the cause of chronic transplant rejection

causes unclear
Ab, immune complexes, slow cellular reaction, recurrence of disease

16

what is another name for hyperacute rejection

antibody-mediated rejection

17

what kinds of people would you test to see if they had preformed antibodies against MHC groups

people who have had a blood transfusion
previous pregnancy
previous transplant

18

what is the mechanism behind antibody mediated rejection

1. pre existing Ab are carried to graft
2. Ab bind to antigen and activate C'
3. C' attracts neutrophils and release lytic enzymes
4. destroys endothelial cells, platelets adhere to injured tissue --> vascular blockage

19

mechanism of acute rejection

1. immune cells pass through the new organ
2. recognises non-self organ
3. takes antigen to draining lymph node on MHC
4. presents to T cells via APC
5. T cells activated and proliferated
6. immune related destruction

20

how do you check whether you have acute rejection

take biopsies and look for T cell infiltrate

21

what are the multiple hits that can cause chronic rejection

ischaemia/reperfusion
dyslipidaemia
infection
hypertension
acute rejection

22

what is the hallmark of of chronic rejection

fibrosis

23

where does fibrosis normally occur in chronic rejection in renal, liver and lungs

around tubules
- renal - around renal tubules (chronic allograft nephropathy)
- liver - around bile duct (bile duct syndrome)
- lungs - around airways (BOS)

24

how do you try and prevent allograft rejection

Matching ABO antigens
matching MHC alleles
immunosuppressive drugs

25

what is the action of cyclosporin

selectively takes out recently activated T cells

26

what is the cocktail of drugs given to a transplant recipient

calcineurin inhibitors (eg cyclosporin)
anti-inflammatory (eg steroids)
anti-proliferative (eg azathioprine)

27

how does cyclosporine inhibit T cells

prevents IL2 transcription needed for proliferation

28

side effects of cyclosporon

nephrotoxicity
prone to viral infection

29

action of azathioprine

inhibit T cell proliferation