Transplantation Flashcards
What is an autograft?
Transplant from one part of the body to another
What is an isograft?
Transplant between genetically identical individuals
Monozygotic twins
What is an allograft?
Transplant between different members of the same species
What is a xenograft?
Transplant between members of different species
What are some criteria for transplantation?
Good evidence that the damage is irreversible
Alternative treatments not applicable
Disease must not recur
How are the chances of rejection minimised?
Donor and recipient must be ABO compatible
Donor most not have anti-donor human leukocyte antigen (HLA) antibodies
Donor be closest HLA match to recipient as possible
Patient must take immunosuppressive treatment
What is the mechanism involved in hyperacute rejection?
Preformed antibodies bind to either ABO blood group or or HLA class I antigens on graft
Type II hypersensitivity reaction
Graft destroyed by avascular thrombosis
What is the time frame for hyperacute rejection?
Within hours of transplantation
What kind of hypersensitivity is involved in acute rejection?
Type IV
What is the frame of time for acute rejection?
Within a few days or weeks of transplantation
What is the mechanism for acute rejection?
Donor dendritic cells stimulate an allogeneic response in local lymph nodes
T cells proliferate and migrate into donor kidney
What is the time frame for chronic rejection?
Months or years after transplant
What kind of cells are hematopoietic stem cells used to restore?
Myeloid and lymphoid
What are the 3 main sources of stem cells?
Bone marrow
Peripheral blood
Cord blood
What is GVHD?
Graft Versus Host Disease
Donor T cells respond to allogeneic recipient cells
Involvement of skin, gut, liver and lungs
How do corticosteroids act as immunosuppressants?
Acting on antigen presenting cells to prevent early stages of graft rejection
Where do cyclosporine and tacrolimus work as immunosuppressants?
Proteins in the intracellular T-cell signalling cascade
What is a drug used for IL-2 blockade in immunosuppression?
Rapamycin
What are some antiproliferative drugs used in immunosuppression?
Azathioprine
Mycophenolate
Mofetil
They prevent lymphocyte proliferation
What are some side effects of rapamycin?
Raised lipid and cholesterol levels Hypertension Anaemia Diarrhoea Rash Acne Thrombocytopenia Decreases in platelets and haemoglobin
