18. Transplant Immunology Flashcards
What are the 3 types of transplant?
Tissue
Haematopoietic stem cell
Solid organ
Which type of transplant is immunologically easy?
Tissue transplant
Doesn’t require immunosuppression
What are the requirements for a something to be considered a tissue transplant?
Must be non-vascularised and non-haematopoietic
What are the most common tissue transplants?
Bone
Heart valves
Blood vessels
Cornea
Where can haematopoietic stem cells be taken from?
Bone marrow
Blood
Umbilical cord
What type of transplant is associated with graft vs host disease?
HSC
Donor T cells attack host
What are the indications for a solid organ transplant?
Irreversible organ failure Disease with a low risk of recurrence Recipient has no infection of malignancy Fit for major surgery Psychologically suitable
What is the importance of HLA matching?
Better outcomes
Less sensitisation makes it easier for a young person when they need a second transplant
What is the probability of having the same HLA as a sibling?
25%
When does hyper acute rejection occur?
<24 hours
What does acute cellular rejection occur?
<6 months
When does acute antibody mediated rejection occur?
<6 weeks
When does chronic rejection occur?
Years
What is the mechanism of hyper acute and acute antibody mediated rejection?
Antibody and complement
Acute inflammation and thrombosis
What is the cause of cellular rejection?
T cell cytotoxic damage
What are preformed antibodies?
Most commonly blood group antibodies and anti-HLAs
Causes hyper acute rejection
How can the body be sensitised to make preformed antibodies?
Blood transfusion
Pregnancy
Previous allograft
What transplant is preformed antibodies not a contraindication for?
Liver
What are the indications for HSCT?
Malignancy
Genetic diseases
Severe autoimmune diseases
What is the process of preparing for a HSCT?
Deplete mature stem cells to prevent graft vs host
Condition recipient: radio and chemo, ablate bone marrow, isolation until WBCs recover
What are the complications associated with HSCT?
Non-engraftment Infection GvHD Malignancy recurrence Toxicity of conditioning
What are the acute symptoms of GvHD?
Rash
GI inflammation
Abnormal LFTs
Damage to bone marrow
What are the chronic symptoms of GvHD?
Skin thickening and scarring
Sicca syndrome
Pneumonitis
Develop immunodeficiency
What is sicca syndrome?
Damage to lacrimal and salivary glands
What drug is given short term post renal transplant?
Anti-CD25: T cell depleting antibody
What drugs are given long term post renal transplant?
Tacrolimus
Mycophenylate
Steroids
What is the function of mycophenylate?
Anti-proliferative
