Transplantation Flashcards
(42 cards)
name the types of graft
xenograft
allografy
isograft
autograft
what is a xenograft?
tissue graft or organ transplant from a donor of a different species from the recipient
what is an allograft?
the transplant of an organ or tissue from one individual to another of the same species with a different genotype
what is an isograft?
from a donor who is genetically identical to the recipient
do isograft receivers still need immunouppression and why?
yes because they will have been exposed to different things e.g. blood transfusion
what is an autograft?
a graft of tissue from one point to another of the same individual’s body
what is MHC?
The major histocompatibility complex (MHC) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates, which in turn determines histocompatibility.
what is histocompatibility?
Histocompatibility, or tissue compatibility, is the property of having
the same, or sufficiently similar, alleles of a set of genes called human leukocyte antigens (HLA)
describe the inheritance of HLS
codominantly
two alleles 6 loci
name the major requirements for tissue typing?
HLA-DR, DP, DQ
HLA-A, B, C
ABO
describe class 1 HLA
The class I molecules are responsible for presenting antigenic peptides from within the cell (eg, antigens from the intracellular viruses, tumour antigens, self antigens) to CD8 T cells
descibe class 2 HLA
the class II molecules present extracellular antigens such as bacteria to CD4 T cells
where are HLA class I found?
all nucleated cells
what recognised HLA I
CD8+
Tc cells
where are HLA class II found?
APCs
what recognised HLA II?
CD4+
Th cells
what kind of HLA is most important in rejection?
class II
draw a molecule of HLA1 and 2
see notes
The MHC genes are codominantly expressed, which means that each individual expresses these genes from both the alleles on the cell surface. what does this mean in regards to transplant?
they are inherited as haplotypes or 2 half sets (one from each parent).t This makes a person half identical to each of his or her parents with respect to the MHC complex. This also leads to a 25% chance that an individual might have a sibling who is HLA identical. Only 30% of transplant recipients have an HLA identical donor.
what are privileged sites?
no vascularisation so:
no sensitisation/no tolerance
no requirement for tissue matching
no immunosuppression
give examples of transplants wth privileged sites
corneal
heart valves
types of living donor
related or unrelated
altruistic
types of deceased donor
brain death
cadaveric death
with living donors there is:
less rejection quicker last longer healthier easier to manage
