Trans Immuno Flashcards
Define allogenic
Individuals of the same species that are genetically different
Autograft
graft tissue from one site to another on the same patient
Syngenic graft
graft between genetically identical patients
Allogenic graft
Two genetically diff patients
zenograft
graft between species…what the fuck
Describe transplant rejection in its most basic form
When an organ is transplanted, the host’s T cells attack the transplant
Describe GVHD in its most basic form
T cells in the transplant attack host tissues…bone marrow transplant
Can alloreactions be fatal during blood transfusions?
Yes.
What are the targets of alloreactivity during blood transfusions?
A,B,O antigens
What type of antibodies does someone with Type O blood have?
Both anti-A and anti B
What type of blood can someone with type Oblood be given?
Only type O blood
Type A blood, what type of antibodies?
Anti-B
Type A blood hosts can be given what type of blood?
O or A
Type B, what type of antibodies?
Anti A
Type B can be given?
O or B
Type AB blood, what type of antibodies
NONE!!
Type AB can be given?
Anything!
What’s the deal with the + or -?
If you’re O+ for instance, you can receive O+ or O-. O- can only receive O-.
Describe hyperacute rejection.
Occurs when the donors blood type does not match up with the recipients. Occurs within minutes. Antibodies bind to the endothelium of the transplanted organ, because it displays the same antigens that are present in the host blood. Complement and clotting screws you up.
Acute rejection
CTLs against MHC complexes. Takes 1-15 days.
Will the second allogenic graft be rejected more quickly than the first?
yes
What is the mechanism of acute rejection
The transplant comes in bearing APCs (dendritic cells) which are doing their normal thing and presenting self antigens. These dendritic cells migrate to the spleen and present to T cells that form effector T cell responses. These T cells migrate to the graft site and kill the graft.
If the HLA haplotypes match, can their still be graft rejection?
Yep. This can occur due to minor histocompatability mismatched in some cases. Takes 30-60 days.
What are the most important HLA loci to match?
A,B,D
Liver transplants require what?
Only blood matching
Corneal require what?
Nothing
What role might the placenta play in keeping a pregnancy from being recognized as an allograft?
Most likelyserves to block mom’s T cells. The placenta itself is fetal tissue but this is not a problem because it has no MHC molecules.
What are Rh Antigens?
Protein antigens on RBCs
Why are they important?
During pregnancy, fetal blood and mothers blood come into contact. If the mom is Rh negative and the child is Rh pos, she will developm Rh antibodies. If she is not vaccinated with Rhogan, anti Rh-antibody after the pregnancy, she could kill her next child if it is also Rh positive.
When should Rhogam be administered?
When a child has compatible blood group antigens to the mother.
What is GVHD
Attach of host tissue by T cells from donor
What are the most affected tissues?
Skin, intestines, liver
What 3 types of compounds are used most frequently as immunosuppresants during transplant?
Corticosteroids, Cytotoxic drugs, Microbial products
What do corticosteroids do?
Inhibit NFkB which is used during cytokine expression. Therefore you have no T cell proliferation
Name 3 cytotoxic drugs
Azathioprine
Cyclophosphamide
Methotrexatee
When do you use azathrioprine?
Following solid organ transplant
When is methotrexate used?
Drug of choice for inhibiting GVHD
What do microbial products do?
Inhibit T cell activation
What do cytotoxic drugs do?
inhibit DNA replication
Cyclosporin A?
Interferes with IL-2. No T cell prolif
Tacrolimus
No T cell prolif
Rapamycin;
No T cell prolif
