transplants

Question 1

autograft

Answer 1

one part of the body to another, same person

ex- skin graft

Question 2

isograft

Answer 2

between genetically identical individuals (MZ twins)

Question 3

allograft

Answer 3

between different members of the same species

Question 4

xenograft

Answer 4

between different species

Question 5

what mediates tissue rejection?

Answer 5

immune system, specifically lymphocytes

Question 6

MHC compatibility and graft survival

Answer 6

increased compatibility = increased survival

graft that differ at multiple loci rejected as quickly as those that only differ at MHC H2

Question 7

direct allorecognition

Answer 7

host T cell recognizes graft MHC as foreign

Question 8

indirect allorecognition

Answer 8

host APC processes graft antigen and presents to host T cells

Question 9

hyperacute rejection

Answer 9

• due to preformed antibodies reacting to allogenic endothelium
• results in activation of complement and rapid intravascular thrombosis/necrosis

Question 10

acute rejection

Answer 10

cellular= CD8 T cells react to alloantigens
humoral= antibodies are reactive as well
overall- parenchymal cell damage, interstitial and endothelial inflammation

Question 11

chronic rejection

Answer 11

T cells produce cytokines that cause inflammation and proliferation of vascular smooth mm = occlusion

Question 12

which type of rejection is the m/c cause of graft failure?

Answer 12

chronic

Question 13

which organ has the highest 1 and 5 year survival rates?

Answer 13

kidney

Question 14

which organ has the highest 10 yr survival?

Answer 14

liver

Question 15

MOA of cyclosporin, tacrolimus

Answer 15

calcineurin inhibitors that block activation of NFAT

Question 16

MOA of mycophenolate

Answer 16

inhibit guanine nucleotide synthesis (inhibit DNA synthesis)

Question 17

MOA of rapamycin

Answer 17

inhibit mTOR and IL-2 signaling

Question 18

MOA of antithymocyte globulin

Answer 18

binds/depletes T cells by phagocytosis or complement activation

Question 19

MOA of Anti-IL-2R antibody

Answer 19

blocks Il-2 binding to receptor, may also be opsonin and help eliminate cells expressing IL-2R

Question 20

MOA of CTLA-4 Ig

Answer 20

blocks CD28 from binding to B7 (blocks costimulation)

Question 21

MOA of Anti-CD52

Answer 21

promotes complement mediated lysis of lymphs

Question 22

which medication is used to treat acute rejection?

Answer 22

antithymocyte globulin

Question 23

MOAs of corticosteroids (5)

Answer 23

• decreased NOS
• decreased adhesion molecules
• increased endonucleases
• decreased PL-A, COX2/increased annexin-1
• decreased IL-1, TNFa, GM-CSF, IL-3, IL-4, IL-5, CXCL8 (decreased inflammation)

Question 24

when does GVHD occur?

Answer 24

when allogenic bone marrow transplants are contaminated with mature T cells

Question 25

what happens in GVHD?

Answer 25

mature T cells present in the graft will attack the transplant recipient and cause rashes, diarrhea, liver disease, enlarged LN, eosinophilia

Question 26

graft vs. leukemic effects

Answer 26

mature T cells will kill leukemic cells (if T cells are eliminated from the graft, there is higher risk of leukemic relapse)

Question 27

GVHD vs. graft failure

Answer 27

GVHD- mature T cells attack recipient

graft failure- mature T cells attack graft

Question 28

why is a fetus “foreign”?

Answer 28

contains paternal antigens

Question 29

4 ways that fetus is a “tolerated allograft”

Answer 29

• trophoblast is devoid of MHC-I and MHC-II making them resistant to attack by maternal T cells
• use HLA-G (non-classical HLA type I) that is resistant to NK cell attack
• trophoblast and uterine epithelial cells secrete TH2 cytokines to inhibit TH1 response
• indolamine 2,3-dioxygenase (IDO) is high at the mat-get interface, reactive T cells are starved for tryptophan and not active

Question 30

when would a fetus be rejected vs not be rejected?

Answer 30

allogenic fetus is at risk for rejection

syngeneic fetus is not at risk