Flashcards in Renal transplantation Deck (49):
What happens to the non-functioning kidneys in renal transplant?
Nothing - leave them where they are
Where is a kidney transplant placed?
Right iliac fossa
Which vessels are kidney transplants anastomosed onto?
External iliac artery and vein
What needs to be compatible with regard to transplants?
Human leucocyte antigen matching (tissue typing)
What is blood group compatibility?
Blood antigens must match as antibodies for the other blood antigens are found within the blood
Which blood group does not have an antibody against it?
What are human leucocyte antigens?
Cell surface proteins which activate the immune system when foreign antibodies bind
What are the 3 important types of HLA with respect to transplantation?
With respect to each HLA A, B & DR there are two antigen subtypes. Why is this?
Each parent passes on one subtype to their offspring
Why is HLA relevant?
If a patient has been exposed to their donors HLA antigen before they might have developed an antibody against it and this will therefore cause tissue rejection
A more closely matched kidney is associated with improved survival length of the transplant. T/F
How might a patient be exposed to other HLA antibodies?
Pregnancy (placental maternal blood flow)
Reduced cold ischaemic time is associated with better transplant survival. T/F
Explain transplant rejection
HLA antigen binds to dendritic cells -->
Antigen presenting cells express antigen on MHC complex -->
Helper T cells are activated -->
Increase B cell efficiency ; complement pathway activation ; increase in NK cells and cytotoxic T cells -->
Antibody production ; Direct cell killing -->
What is the difference between cellular rejection and antibody mediated rejection?
Cellular rejection - NK cells and CD8 cells
Antibody mediated - B cells
Immunosuppression increases the risk of what?
Which infections are immunosuppressed patients prone to?
CMV (herpes group)
Which malignancies are immunosuppressed patients prone to?
Non melanoma skin cancer (SCC)
Post transplant lymphoma
Why is CMV important in terms of transplant immunology?
Giving a patient not infected with CMV a CMV infected kidney is bad news unless you give antivirals (valganciclovir)
How is pneumocystis jirovecii treated?
EBV post-transplant increases risk of what?
How is post transplant lymphoma treated?
Reduction in immunosuppression + anti cancer agents
What biochemical marker might help to warn of kidney transplant rejection?
Which cells must be repressed post-transplantation?
T helper cells
Hence complement & cytokines
List the types of transplant rejection
What causes hyperacute transplant rejection? How long does it take to occur? How is it managed?
Preformed antibodies to transplant antigens
How is acute transplant rejection caused? How is it managed?
T cells or B cells
Increased immunosuppression (+ steroids in short term)
How is chronic transplant rejection caused? How is it managed?
Immunological and vascular deterioration
Unsure how to treat
Describe how transplant patients are immunosuppressed
Induction - high dose steroids, MMF, cyclosporin, tacrolimus, antibodies
Consolidation - lowered doses
Maintenance - balanced low doses
Name two calcineurin inhibitors
How do calcineurin inhibitors work?
Reduce NK and CD8 cell activation and thus decrease cytokine release (preventing B cell proliferation and antibody production)
What are the side effects of calcineurin inhibitors?
Diabetes (in at risk populations)
Which organ are calcineurin inhibitors metabolised by? Why is this relevant?
The specific liver pathway that metabolises calcineurin inhibitors also metabolises lots of other drugs hence drug interactions can be an issue
How do azathioprine and mycophenolate work?
Block purine synthesis thereby suppressing the proliferation of lymphocytes and B cells
What are the side effects of azathioprine and mycophenolate?
Which drug should you not give azathioprine with?
How do steroids work with regards to immunosuppression?
Non selective suppression of T cells and B cells
What are the side effects of steroids?
What types of kidney donation exist?
Deceased brain dead
Deceased cardiac death
Which type of diabetes patients are suitable for pancreas transplantations?
Type 1 diabetics with renal failure
What is the criteria for a patient to be eligible for transplant?
Life expectancy >5 yr
No cadaveric transplant if >6 months prior to starting haemodialysis
Tissue type match (person who has been on list longest gets organ)
How must transplant patients be assessed?
CVS risk (ECG, cholesterol, ETT +/- angiogram, echo)
Virology (hepatitis, HIV, CMV, EBV)
Investigation of co-morbidity
Which viruses should be treated prior to transplant?
What are the absolute contraindications to transplant?
Severe airways disease
Severe peripheral vascular disease
How is a live donor assessed?
GFR (direct measure)
24hr blood pressure
X-match against recipient
What might a renal transplant scar look like?
Like appendix scar but bigger and with underlying mass
What are the complications of transplant?
Ureteric stricture and hydronephrosis
Why do post transplant patients get a central line?
To measure central venous pressure