Immunology 4: Tissue transplant

Question 1

autograft

Answer 1

one part of body to other

Question 2

allograft

Answer 2

between members of same species

Question 3

hyperacute rejection - antibody mediated

Answer 3

minutes to hours

type II hypersensitivity reaction

pathology: vascular process i.e. in blood vessels by affecting blood cells

Question 4

acute rejection - direct pathway of allorecognition

Answer 4

direct pathway of allorecognition (HLA mediated)

weeks to months following transplantation

Type IV hypersensitivity i.e. T cell mediated and delayed hypersensitivity

effector T cells respond to HLA differences between donor and recipient

treatable with immunosuppresive drugs

after transplantation, donor derived dendritic cells migrate to spleen and activate recipient T cells which recognise proteins as foreign, become activated and migrate to kidney where they will destroy the graft

Question 5

chronic rejection - indirect pathway of allorecognition

Answer 5

onset: months to years

dominated by vascular changes e.g. thickening of the intima causing inflammation and late onset ischaemia

increases in incidence with better control of acute rejection

treatment: regraft

Question 6

types of alloreactions

Answer 6

transplant rejection

graft versus host disease

Question 7

graft versus host disease

Answer 7

bone marrow T cells attack the recipients tissues
> occurs due to mismatches in MHC

takes weeks to months

T cell mediated
CD8+ dominated

tissues affected:
skin, GIT, liver

Question 8

PTLD (post transplant lymphoproliferative disease)

Answer 8

B cell disease affecting head and neck and GIT

caused by EBV (epstein barr virus) reactivated following immunosuppression post transplantation

EBV integrates into B cell genome and causes lymphomas

Question 9

immunosuppresive drugs

Answer 9

1. corticoisteroids
2. cytotoxic drugs
3. microbial immunosuppresive products
4. immunosuppresive antibodies s