Transplantation Flashcards
1
Q
Autograft:
A
From one part of the body to another.
2
Q
Isograft:
A
Between genetically identical individuals.
3
Q
Allograft:
A
Between different members of the same species.
4
Q
Xenograft:
A
Between members of different species.
5
Q
Direct recognition:
A
T cells may recognize allogeneic MHC molecules on the graft.
- Displayed by donor dendritic cells in graft.
- May be processed and presented by host dendritic cells.
- T cells become activated.
6
Q
Indirect recognition:
A
If graft cells are ingested by recipient dendritic cells.
- Donor alloantigens are presented by self MHC molecules on recipient APCs.
7
Q
Hyperacute rejection:
A
- Occurs within minutes or hours after transplant; surgeon can see this occur.
- Antigen-antibody reaction; pre-formed antibodies.
- Thrombotic occlusions of capillaries.
- Fibrinoid occlusion of arterial walls.
- Kidney cortex get infarction with necrosis.
- Must be removed.
8
Q
Acute rejection:
A
- Occurs in days after transplant or much later if patient stops immunosuppression.
- Both humoral and cellular mechanisms.
- Can respond to increased immunosuppression.
- Extensive mononuclear infiltrate.
- Endothelitis: CD8 cells invade and damage vascular endothelium.
- Called tubulointerstitial rejection
9
Q
Chronic rejection:
A
- Occurs months to years.
- See slow rise in creatinine.
- Vessels - dense intimal fibrosis that occludes the vessel lumen.
- Interstitial fibrosis.
- Tubular atrophy with loss of renal parenchyma.
- Glomerular changes: chronic transplant glomerulopathy - duplication of basement membrane.
10
Q
Graft-versus host disease:
A
- Caused by the reaction of grafted T cells with alloantigens of the recipient.
- Recipient is immunocompromised; unable to reject allogeneic cells in the graft.
- Develops when significant numbers of T cells are transplanted.
- Often directed to minor histocompatibility antigens.
- Target organs are skin, liver and intestine.
