Immunology transplantation Flashcards
(44 cards)
What is the key function of the immune system?
Protection from pathogens and surveillance for tumours
Components of the innate immune system include:
- Macrophages
- Neutrophils
- Complement & natural antibodies (IgM)
What are the components of the adaptive immune system?
- Dendritic cells (DC) - antigen presentation
- T cells - helper and cytotoxic T cells
- Natural Killer (NK) cells - cytotoxic
- B cells - antibody generation & memory
What is the Major Histocompatibility Complex (MHC) in humans called?
Histocompatibility Locus Antigen (HLA)
What do HLA molecules do?
Imprint ‘individuality’ on cells and are pivotal in the generation of immune responses
What are the Class I HLA molecules?
- HLA-A
- HLA-B
- HLA-C
What is the role of Class I HLA molecules?
Present peptides from internally processed proteins and help recognize infected cells
What are the Class II HLA molecules?
- HLA-DP
- HLA-DQ
- HLA-DR
What is the function of Class II HLA molecules?
Present antigenic peptides derived from digested material to T cells
What is the T cell receptor complex and costimulation?
A system that activates T cells for immune response
What characterizes rejection of transplanted organs?
Directed at specific antigens and may be cell or antibody-mediated
What is HLA profiling used for?
To allocate kidneys and match donors with recipients
What immunosuppressive treatments are used in transplantation?
- Corticosteroids
- Calcineurin inhibitors (CNI) like Tacrolimus
- Anti-proliferative agents like mycophenolate mofetil (MMF)
- Monoclonal and polyclonal antibodies
What types of organs can be transplanted?
- Kidney
- Pancreas
- Liver
- Lung
- Heart
- Small Bowel
- Cornea
What factors are considered in patient assessment for transplant eligibility?
- Age
- Primary cause of renal failure
- Comorbid diseases
- History of infections
- History of tumours
- Urological disease
What are the types of transplantation?
- Cadaveric Tx
- DCD (donated after cardiac death)
- DBD (donation after brain death)
- Living related donor Tx
What is the importance of blood group compatibility in kidney transplantation?
Ensures the recipient’s and donor’s blood groups are compatible
What does immunological ‘X-match negative’ mean?
No reaction between donor lymphocytes and recipient serum
What are the types of rejection in transplantation?
- Hyperacute rejection
- Acute rejection
- Chronic rejection
What occurs during hyperacute rejection?
Occurs when the Tx carries antigens to which the recipient is already sensitised
What are the features of acute rejection?
- Tubular damage
- Infiltration of T cells and macrophages
- Possible vascular rejection
What is the treatment for acute rejection?
- High dose methyl prednisolone
- Change to a more potent immunosuppressive agent
- Anti-T cell antibody
What are the features of chronic rejection?
- Progressive renal dysfunction
- Interstitial fibrosis
- Vascular disease
What factors contribute to chronic rejection?
- Increased HLA mismatch
- Previous acute rejection
- Poor drug compliance
- Prolonged cold ischaemia time