Kidney Transplantation Flashcards
Define transplant
Transfer (living tissue or organ) to another part of the body to or another body
Define autologous transplant
Donor and recipient are the same individual
Define syngenic transplant
Donor and recipient are genetically identical twins
Define allogenic transplant
Donor and recipient are not genetically identical twins but are of the same species
Define Xenogenic transplant
Donor and recipient are from different species
What the difference in survival is the donor is living and not dead?
5 years.
What systemic is place in the UK for donations?
NHS Blood and Transplant (NHSBT)
Blood type A what antigen and antibody are present and who are compatible donors?
Antigen on RBC: A
Antibody is plasma: anti-B
Compatible donors: A, O
Blood type B what antigen and antibody are present and who are compatible donors?
Antigen on RBC: B
Antibody is plasma: anti-A
Compatible donors: B, O
Blood type AB what antigen and antibody are present and who are compatible donors?
Antigen on RBC: AB
Antibody is plasma: none.
Compatible donors: A, B, AB, O
Blood type O what antigen and antibody are present and who are compatible donors?
Antigen on RBC: O
Antibody is plasma: anti-A, anti-B
Compatible donors: O
What’s the risk of donating with blood group incompatibility?
Hyperacute rejection of transplated organ
What is the MHC?
Major Histocompatibility complex
- genes present which are associated with acceptance and rejection of transplanted material
Where is MHC located?
Chromosome 6
What does MHC contain?
Human leukocyte antigen (HLA)
- polymorphic
How many classes of HLA are there (relevant)
HLA I
HLA II
What does HLA I bind?
peptides derived from IC proteins
- including peptides from viruses
What are the HLA I molecules?
HLA-A
HLA-B
HLA-B
Where are HLA I molecules expressed?
All cells, including platelets
Where are HLA I polymorphs located?
Exons 2 and 3
Where are HLA II polymorphs located?
Exon 2
What’s the structure of HLA I?
3 alpha units with 1 beta unit
Whats the structure of HLA II?
2 alpha units
2 beta units
What does HLA II bind?
peptide derived from EC and cell surface peptide
- including those from bacteria
What are the HLA II molecules?
HLA-DR
HLA-DQ
HLA-DP
Where are HLA II molecules expressed?
APCs
What’s the difference between HLA I and HLA II?
- structural differences affecting peptide binding
- specialised
- immune response
Why is there huge diversity within a HLA population?
increases chances of species surviving after exposure to pathogen
Give an advantage to HLA polymorphism
Protection against different pathogens
Give a disadvantage to HLA polymorphism
Transplantation of tissues and organs between HLA incompatible individuals
How can HLA mis-matching be overcome?
Immunosuppression
When should you definitely avoid transplantation?
When donor specific antibodies are present in recipient
How can patients make antibodies against non-self HLA?
- Pregnancy
- Blood transfusions
- Previous transplant
- Viral infection
What is HLA sensitisation
Status of recipients must be determined prior to transplant
Give one contraindication to transplant
presence of donor specific HLA antibodies
How are transplants allocated in the UK
- Paediatric patients (HLA match), highly sensitised - priority based on waiting time
- Other paediatric patients (HLA match) - priority based on waiting time
- Adults (HLA match), high sensitised - priority based on waiting time
- Other adult patients - priority based on waiting time
- All other eligible patients
* 1, 2, and 3 priority given according on a point score based on: waiting time, HLA match, age, age difference, location, HLA homozygosity, and blood group match
What is meant by highly sensitised?
A highly sensitised immune system is one that that would attack the transplanted kidney or pancreas
Have high donor antibodies (>85% across panel)
What test would you perform prior to transplant?
- HLA type patient
- HLA type donor
- Screen patients for preform HLA allo-antibodies (every 3months)
- Cross-match patient and donor
What would you do post-transplant?
Monitor for presence of donor-specific antibodies
How many transplants do patients usually receive?
> 1
