Immunology 10. Transplant Flashcards
Acute vs Chronic GvHD?
Acute vs Chronic GvHD?
first 100 days of transplant vs after 100 days of transplant
Antibody binding in hyperacute rejection results in?
Antibody binding in hyperacute rejection results in?
Opsonization
Complement dependant cytotoxicity
ADCC
Clinical signs of acute GvHD?
Clinical signs of acute GvHD?
Rash, Diarrhoea, and Hepatitis
Compare direct vs indirect allorecognition?
Compare direct vs indirect allorecognition?
Direct allorecognition = donor APC present donor derived peptide on donor MHC to recipient T cell –> acute rejection
Indirect allorecognition = recipient APC present donor derived peptide on recepient MHC to recipient T cell –> chronic rejection
Direct allorecognition = Donor APC sabo own donor peptide on own donor MHC to recipient T cell
Indirect alloregnition = Recipient APC catch donor peptide on recipient MHC to recipient T cell
The difference is just the APC and MHC origin. Peptide and T cell is alw recipient!!
Complications of HSCT (Hematopoietic stem cell transplantation)?
Complications of HSCT (Hematopoietic stem cell transplantation)?
1) Infection
2) Graft rejection
3) GvHD (also seen in solid organ transplants, but more common for HSCT and other stem cell transplants)
Define graft rejection
Define graft rejection
Adaptive immune responses to human antigens in transplanted cells that are perceived as foreign
TLDR, my body saying no to your liver
HLA genes are highly ____
HLA genes are highly ____
Polymorphic
How do we prevent hyperacute rejection?
How do we prevent hyperacute rejection?
1) Screen potential recipient for donor-specific antibodies (mainly anti-donor HLA class I antibodies)
2) Select for ABO compatibility
How does HvG antibody response work?
Pathogenesis of acute rejection?
Pathogenesis of acute rejection?
Basically activation of CD8 killer cells
Pathophysiology of acute GvHD?
Pathophysiology of acute GvHD?
Donor T cells recognise allogenic MHC-peptide complex on recipient APC –> priming of donor naive T cells –> donor effector T cells recognise allogenic MHC-peptide complex on recipient tissue cells –> acute GvHD
Recall: what happens during negative selection of T cells in the thymus?
Recall: what happens during negative selection of T cells in the thymus?
We ensure that there is no excessively strong binding to self antigen
What are complications of renal transplant?
What are complications of renal transplant?
Infection
Graft rejection (Hyperacute, acute or chronic)
Relapse of disease
What are some patterns of allogeneic responses for HSCT?
What are some patterns of allogeneic responses for HSCT?
HvG
GvHD
GvLeukemia
What are the conditions in which GvH disease occurs?
What are the indications for Haematopoietic Stem Cell Transplantation?
What are the indications for Haematopoietic Stem Cell Transplantation?
1) replace dysfunctional lineages in haemotological conditions e.g aplastic anemia
2) malignancy: blast (eradicate residual tumour cells) and replace HSCs
What does HLA stand for? What is it?
What does HLA stand for? What is it?
Human Leukocyte Antigens (HLA). Alternative name is human MHC.
They are the antigens of allografts that serve as the principal determinants of immune rejection.
They are expressed on most cells.
What is acute rejection?
What is chronic rejection?
What is chronic rejection?
Mechanism not impt, not tested.
What is graft vs leukaemia effect?
What is graft vs leukaemia effect?
Leukaemia cells express recipient MHC
So GvH alloresponse of donor t cells can have beneficial effect of killing tumour cells
What is hyperacute rejection?
What is hyperacute rejection?
Pre-formed anti-donor abs in recipient binding to donor HLA/blood group antigens
What is indirect allorecognition?
What is indirect allorecognition?
Indirect allorecognition = recipient APC present donor derived peptide on recepient MHC to recipient T cell –> chronic rejection
What is involved in recipient selection in renal transplant? (IMPT!!!)
What is involved in recipient selection in renal transplant? (IMPT!!!)
ABO compatibility
Negative serum cross-match with donor’s T cells
HLA match as close as possible especially at D loci
Basically: check yourself and check the donor
What is the chance that 2 siblings will share the same HLA alleles?
What is the chance that 2 siblings will share the same HLA alleles?
**only 1 in 4 chance. **
What is the Host vs Graft T Cell response?
What is the Host vs Graft T Cell response?
Aka graft rejection cuz recipient bone marrow not fully ablated
Why does allogeneic T cell response occur?
Why does allogeneic T cell response occur?
Recipient T cells recognise donor HLA molecules as foreign
Why is there increased risk of infection during HSCT?
