Lecture 28 - Transplantation Immunology Flashcards
1
Q
What are the two causes for allograft rejection
A
- t cell-mediated rejection
- antibody-mediated rejection
2
Q
What is T cell mediated rejection
A
- donor and recipient APCs migrate to secondary lymphoid organs
- APCs meet T cells in lymphoid organs
- effector T cells migrate to graft
3
Q
What is antibody mediated rejection
A
- donor and recipient APCs mifrate to secondary lymphoid organs
- APCs meet T cells in lymphoid organs
- T cells provide help to B cells
- plasma cells develop
- plasma cells home to bone marrow
- HLA Ab production
- HLA Ab enters the blood and reachesthe graft
- effector T cells migrate to graft
- Ab interaction with HLA and other membrane-bound molecules, antibodies attract complement
- classical complement pathway activation
- Ab dependent cell-mediated cytotoxicity
4
Q
What is hyperacute rejection
A
- pre-formed antibodies bind to the graft endothelium directly after transplantation
- takes minutes to hours
5
Q
What is acute cellular rejection
A
- t cells destroy the graft parenchyma by cytotoxicity and inflammatory reactions
- takes weeks to months
6
Q
What is acute humoral rejection
A
- antibodies damage graft vasculature
- takes weeks to months
7
Q
What is immunological memory
A
- ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously
8
Q
What is chronic rejection
A
- caused by both humoral and cellular immunity
- intimal thickening and fibrosis of graft vessels as well as graft atrophy
- takes months to years
9
Q
How is rejection diagnosed
A
- the initial clinical manifestation is often non-specific
- ## diagnosis is based on clinical data obtained from a biopsy, blood test results, and HLA antibody testing
