Immunology transplantation Flashcards
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
What is an increased risk factor for graft failure related to HLA mismatch?
Increased HLA mismatch (1-2-1 vs 0-0-1)
HLA mismatch refers to the differences in human leukocyte antigen between donor and recipient, affecting transplant success.
What previous medical event can increase the risk of graft failure?
Previous acute rejection
Acute rejection episodes can sensitize the immune system, making future rejections more likely.
What aspect of patient care can lead to poor drug compliance?
Low tacrolimus levels
Tacrolimus is an immunosuppressive medication critical for transplant patients to prevent rejection.
What is the significance of prolonged cold ischemia time (CIT) in kidney transplants?
Prolonged cold ischaemia time of kidney prior to surgery
CIT is the duration the kidney is preserved before transplant, affecting graft survival.
What viral infection is a risk factor for graft failure?
Cytomegalovirus (CMV) infection
CMV can lead to complications in transplant patients, impacting graft function.
What is one management strategy for chronic rejection?
Optimise immunosuppression
Proper immunosuppression management is crucial to prevent graft rejection and preserve function.
What are some factors promoting graft failure?
- Poor blood pressure control
- Proteinuria
- Age of donor and ‘donor disease’
These factors can negatively impact the success of kidney transplants.
True or False: There is a specific treatment available for chronic rejection.
False
Most chronic rejection cases do not have a specific treatment and require management strategies.
What prophylactic treatment is suggested for bacterial infections in transplant patients?
Cotrimoxazole for urinary tract infections and chest infections
Prophylactic antibiotics help reduce the risk of infections in immunosuppressed patients.
Which virus can lead to renal dysfunction in kidney transplant recipients?
BK virus
BK virus is a common complication in transplant patients, often requiring adjustments in immunosuppression.
What is a common skin cancer prevention strategy for transplant patients?
UV block, avoid sun, skin surveillance
Immunosuppression increases the risk of skin cancers, necessitating preventive measures.
What is Post Tx Lymphoproliferative disorder (PTLD) associated with?
Infection with Epstein Barr virus
PTLD can occur in immunosuppressed patients, requiring careful management of immunosuppression.
What are the side effects of calcineurin inhibitors?
Nephrotoxic effects
Patients on calcineurin inhibitors require regular monitoring of drug levels to prevent kidney damage.
What is the relationship between immunosuppressive drugs and diabetes?
Increased risk of diabetes (steroids and tacrolimus)
Certain immunosuppressive drugs can lead to metabolic complications, including diabetes.
Fill in the blank: The immune system is there for a _______.
[reason]
The immune system plays a crucial role in protecting the body from infections and diseases.
What is a future direction in transplantation technology?
Xenotransplantation using genetically engineered (humanised) pigs
This approach aims to overcome donor shortages and improve transplant outcomes.
What treatment was used for Patient B’s acute antibody-mediated rejection?
Intensive plasma exchange and rituximab
Rituximab is an anti-CD20 antibody that depletes B cells, crucial in managing antibody-mediated rejection.
What complication did Patient B develop after initial improvement?
Cell mediated rejection
This indicates the complexity of rejection processes post-transplant, requiring ongoing management.
What virus was identified in Patient B during bronchoscopy?
Respiratory syncytial virus (RSV)
RSV can cause significant respiratory issues in immunocompromised patients.
What is a key consideration when using immunosuppressive therapies?
Careful management of the immune system
Balancing immunosuppression is vital to prevent rejection while minimizing infection risks.
