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Y2 MCD - Immunology - Laz > Transplantation > Flashcards

Flashcards in Transplantation Deck (27)
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1
Q

What is the difference between life-saving and life-enhancing transplantation?

A

Life-saving – other life-supportive methods are not fully developed or other life-supportive methods have reached the end of their possibleuse
Life-enhancing – other life-supportive methods are less good e.g. Kidneys and dialysis – the organ is not vital but it improves the quality of life

2
Q

What are the different types of transplants?

A

Autograft – within the same individual
Isografts – between genetically identical individuals of the same species
Allograft – between different individuals of the same species
Xenograft – between individuals of different species
Prothetic graft – artificial material e.g. plastic, metal

3
Q

Give an example of an autograft.

A

Coronary artery bypass graft

4
Q

What tissues can xenografts be used for?

A

Heart valves

Skin

5
Q

What are the two types of deceased donor?

A

Donor after brain death – brain dead but heart-beating

Donor after cardiac death –non-heart beating donors

6
Q

What must be confirmed with DBD donors?

A

Irremediable structural brain damage of known cause
Apnoeic coma that is NOT due to depressant drugs, hypothermia, neuromuscular blockers etc.
Must be able to demonstrate a lack of brain stem function (e.g. pupils both fixed to light)

7
Q

What must be excluded before harvesting organs from a deceased donor?

A

Viral infection
Malignancy
Drug abuse, overdose or poison

8
Q

How are the organs maintained once they’ve been removed?

A

They are rapidly cooled and perfused

NOTE: absolute maximum cold ischaemia time for the kidneys is 60 hours

9
Q

What is the difference between transplant selection and transplant allocation?

A

Selection – access to the waiting list

Allocation – access to the organ

10
Q

What is the nationwide system of transplant allocation based on?

A

Equity – fairness

Efficiency – what is the best use of the organ in terms of patient and graft survival?

11
Q

What are the 5 tiers of patients on the organ transplant waiting list based on?

A

Paediatric or adult

Highly sensitised or not

12
Q

What are the 7 elements that are used to decide upon organ allocation?

A
Waiting time  
HLA match and age combined  
HLA-B homozygosity  
HLA-DR homozygosity  
Donor-recipient age difference  
Location of patient relative to donor  
Blood group match
13
Q

What are the main obstacles to donation?

A

Contraindication for use of that organ
Family not approached for consent
Family declined consent

14
Q

Describe some other strategies for increasing transplantationactivity.

A

Use marginal donors e.g. elderly and sick
Transplantation across compatibility barriers
Exchange programmes – organ swaps for better tissue matching
Future – xenotransplantation + stem cell research

15
Q

What are the main antigens that must be considered when determining the compatibility of an organ for transplant?

A

ABO

HLA

16
Q

On which chromosome is the HLA gene encoded?

A

Chromosome 6

17
Q

What are the two classes of HLA and which HLA subtypes are in each class?

A

HLA Class I – A, B and C = present on all cells

HLC Class II – DP, DQ, DR = present on specialised immune cells

18
Q

What are the most important HLA subtypes in organ compatibility?

A

A
B
DR
NOTE: the fewer the number of mismatches, the better the outcome for the recipient

19
Q

What are the two types of organ rejection?

A

T cell-mediated rejection

Antibody-mediated rejection (B cells)

20
Q

How is rejection diagnosed?

A

Histological examination of graft biopsy

21
Q

How is rejection classified based on the time of onset?

A

Hyperacute
Acute
Chronic

22
Q

How may organ rejection present?

A

Deteriorating graft function e.g. rise in creatinine with kidney transplant
Pain and tenderness over graft
Fever

23
Q

How can rejection be prevented?

A

Maximise HLA compatibility

Life-long immunosuppressive therapy

24
Q

List some treatments for Antibody-mediated rejection.

A
Anti-CD20 antibodies  
Bortezomib (proteasome inhibitor)  
Anti-complement antibodies  
Plasma exchange  
IVIg 
Splenectomy
25
Q

What is normally used for baseline immunosuppression following transplantation?

A

Signal transduction blockade: usually a calcineurin inhibitor (tacrolimus or cyclosporin)
Antiproliferative agent (e.g. azathioprine)
Corticosteroids

26
Q

Describe the treatment of episodes of acute rejection.

A

T cell mediated: steroids and anti-T cell agents

Antibody mediated: IVIg, plasma exchange, anti-CD20, anti-complement

27
Q

What is a major risk of the extensive immunosuppressive therapythat is given to patients following transplantation?

A

Increased risk of infection (including opportunistic infection)