MSI Transplant Immunology Flashcards
What is an example of an immune-privileged site of transplantation?
Corneal transplants can be accepted by the donor without any evidence of rejection d/t the fact that there is no vascularisation and no way for the immune cells to reach the cornea.
In vascularised solid organ transplants, these are sites with a good blood supply so that the immune system can reach them, it is absolutely necessary for genetically similar donors to be screened, and therefore reduce the risk of …
rejection
Bone marrow transplants or haematopoietic transplants which are similar to vascular solid organ transplants. In these cases, the patients are heavily immunocompromised, so they will develop a higher risk of …
graft vs host disease
Transplant between genetically identical individuals (homozygos twins) (iso/syngeneic)
Isograft
Transplant between genetically disparate member of the same species (allogeneic)
Allograft
Transplant to another site on the same individual (e.g. after a burn) (autologous)
Autograft
Transplant to a different species (pig or monkey to human) (xenogeneic)
Xenograft
Most common example of this is pig valves for heart valve replacement
** What is the most common type of transplantation?
Allograft
The response of the recipient’s immune system against the donor’s. The foreign Ags and the T lymphocytes are the main players in this response.
Host vs graft dz
Immune responses such as host vs graft in allogeneic organs and tissues is a mainly __________ dependent process.
T cell
In allogeneic haematopoietic stem cell (ie bone marrow) transplant, the types of immune responses that can occur include both ….
Host vs graft and graft vs host disease
The time from the interruption of circulation to the donor organ to the moment when organ is flushed with hypothermic preservation solution.
from the moment the organ is removed from the cold preservation solution until the time that blood supply is reinstated.
Warm ischemic time
The time from the moment the organ is flushed with cold preservation solution until its removal from that solution.
Cold ischemic time
A transplant that is from a recently deceased donor
Examples: heart, lung, pancreas, liver, kidney, cornea, limbs
Cadaveric donor transplant
A transplant were the donor is alive and related (there have been exceptions)
Examples: kidney, liver segments
Live-related donor transplant
What step should be taken to prevent organ allograft rejection between identical twins?
HLA matching is required to ensure that no immune response will happen
** What is the standard of care for prevention of organ allograft rejection?
Immunosuppressive drugs
“The Holy Grail of Transplantation” is to be able to induce immune __________ without causing any serious complications to the recipient or the organ
tolerance
A genetic locus that we have to think about when we consider any type of genetic transplant is the ___ antigens, which can be extremely polymorphic
HLA
** The effects of_________ mismatchesare the most important in the first 6 months after transplantation
HLA-DR
** Which genes illicit the strongest responses by T cells and antibodies in transplant rejections?
HLA antigens
Transplants with the highest amount of genetic mismatches had the __________ lifespan of the organ
shortest
** The effects of which genes are the most important when we consider transplant matching?
HLA DR
What is the most important effector of rejection?
MHC- BY FAR
Others include T cells (with antigen MHC to become activated)
B cells
Antigen presenting cells (Activate T cells
Endocytose antigen and display it on MHC molecules)
** What are the main targets for rejection in response to allografts?
Major Histocompatibility antigens (MHC Class I) which are expressed on all nucleated cells
And MHC Class II antigens found on B cells, APC, Monocytes/macrophages
Encode molecules crucial to the initiation and propagation of immune response
HLA (or MHC) complex