Transplantation Flashcards
What is xenograft?
Transplant across different species
E.g. Porcine heart valve for human
What is Allograft?
Transplant within the same species
What is Autograft?
Transplant within the same individual
What is immunological significance of transplantation?
It is important to consider >>> “whether the transplant is immunogenic”
If yes >>> consider “immunosupression by drugs”
Are cardiac valve transplants immunogenic?
No
Cardiac valve transplants are not immunogenic.
So, they do NOT require immunosupression.
Are all transplanted tissues immunogenic?
Almost all
(except. cardiac valve transplants)
Do all transplanted tissues require immunosupression?
Almost all
(except. cardiac valve transplants)
Why do we use immunosupression in the setting of an organ transplant?
To prevent host rejection
Why do we use immunosupression in the setting of a bone marrow transplant?
To prevent GVHD (graft vs host disease)
(Here immune system is the organ that has been transplanted)
Key principle to minimise the risk of host-rejection before transplantation of a tissue/organ
Match HLA genotype (as closely as possible)
The importance of HLA matching depends upon-?
The “immunogenicity” of the tissue being trasnplanted
Importance of HLA matching in renal transplantation and liver transplantation
- More important for renal transplantation
- Relatively unimportant for liver transplantation
Types of transplant rejection
- Hyperacute
- Acute
- Chronic
Hyperacute transplant rejection: mechanism
Pre-existing humoral immunity
Acute transplant rejection: mechanism
T cell driven/mediated
Chronic transplant rejection: mechanism
Variable
(Includes: non-compliance with medication)
Hyperacute transplant rejection: Time of onset
Immediate (i.e. while still on the operating table)
Acute transplant rejection: Time of onset
Weeks to months
Chronic transplant rejection: Time of onset
Months to years
Hyperacute transplant rejection: Clinical features
Severe systemic inflammatory response
Acute transplant rejection: Clinical features
Most patients experience some form of acute rejection
But when it is severe form >> characterised by >>
- Photosensitive rash
- Abdominal pain
- Jaundice
Chronic transplant rejection: Clinical features
But it occurs after “repeated episodes” of acute rejection
= means repeated episodes of features of acute rejection
- photosensitive rash
- abdominal pain
- jaundice
A problem specially with “lung transplantion”
Which type of transplant rejection is more common (than other types) in lung transplantation?
Chronic transplant rejection (Repeated episodes of acute rejection)
Do cardiac valve transplantation need immunosupression/immunosupressive drugs?
NO
Because they are NOT immunogenic
