Transplantation Immunology Flashcards
process in which an individual receives cells or tissue from a second individual
transplantation
a life saving procedure for end stage organ failure, malignancies, autoimmune diseases, immunodeficiency disorders and other
transplantation
classified according to genetic disparity between the donor and the recipient (MHC)
transplants (grafts)
tissue form one area to another from the same individual
autograft
tissue from identical twins
syngeneic graft/ syngraft/ isograft
tissue from different individuals in the same species
allograft
tissue from different species
xenograft
treatment of hyperacute allograft rejection
graft removal
- occurs within mins to hrs after vascular supply
- preformed anti-HLA Abs
- antibody mediated
- recipeint has been previously exposed to donor MHC Ags
hyperacute allograft rejection
- weeks after engraftment
- caused by CD4 and CD8 t cell activation
acute allograft rejection
severity in acute allograft rejection is dependent on?
number of T cell clones activated
- weeks, months, or years post transplantation
- delayed type of hypersensitivity
chronic allograft rejection
treatment of chronic allograft rejection
graft removal
attack the tissues of immunocompromised recipient
T lymphocytes of immunocompetent donor
cannot attack the graft with the same magnitude
immune system of the recipient
targets T cells and are at risk of infection, malignancy and drug associated toxicity
patients under immunosuppressive therapies
examples of immunosuppressive therapies?
corticosteroids, antimetabolic agents, calcineurin inhibitors, monoclonal antibodies
types of histocompatibility screening
serologic typing, cellular typing and molecular typing
are screened to ensure best possible genetic match of MHC to minimize the likelihood of rejection
recipients and potential donors
determination of compatibility by the differences in MHC
tissue cross-matching
method of choice until development of molecular approaches
serologic typing
donor and recipient tissues are tested separately with Abs for various MHC antigens and the reaction is compared
serologic typing
disadvantage of serologic typing
allelic differences cam only be detected if an Ab is available for the allele
in vitro test used to mimic in vivo conditions of transplantation
mixed lymphocyte reaction
why are the donor cells and recipient cells incubated for several days?
to allow T cells to be activated and proliferate in response to disparate MHC antigens
is Limited to living donors only
mixed lymphocyte reaction
- DNA is cleaved by enzymes to obtain pattern of fragmentation
- Degree of disparity is assessed by comparing patterns of fragmentation
RFLP analysis
- Direct amplification of a particular DNA sequence selected by the use of primers that isolates the gene of interest
- Degree of disparity is assessed by comparing the selected sequences
- May not be able to predict severity of rejection
- Do not have the time constraint of MLR and is superior to serological approaches
PCR
