Finals Autoimmunity Flashcards
What is clonal deletion?
If B or T cells are auto-reactive they are killed through apoptosis
What is apoptosis
Programmed cell suicide/death
What is central tolerance?
Clonal deletion
What is peripheral tolerance?
If B or T cells encounter auto-antigens in the periphery
What are the two steps that occur in peripheral tolerance?
- Stimulation is so strong it induces activation-induced cell death (apoptosis)
- Recognition of antigen in the absence of costimulation leads to anergy
What is anergy?
Functional unresponsiveness, cell is still alive but unable to be activated
What are the four ways autoimmunity can occur?
- auto-reactive T cells escape thymic deletion
- failure of peripheral regulation
- polyclonal/bystander activation (wrong place wrong time)
- molecular mimicry (pathogen looks like self)
What is molecular mimicry?
Antigens from pathogens look like self antigens and an immune response against pathogen can lead to autoimmunity
What is and does cyclophosphamide do?
- alkylating agent
- cross-links DNA resulting in death of proliferating cells (immune cells)
- total immune suppression
What is and does plasmapheresis do?
-machine that removes either all antibodies or specifically remove autoimmune antibodies from blood
When is a bone marrow transplant useful?
The autoimmunity is caused by the immune system , you can replace the immune system
What is an autologous bone marrow transport?
Replace bone marrow with stem cells collected from the patient
What is an allogeneic bone marrow transport?
Replace bone marrow with matched bone marrow from another person
What are the types of grafts?
- autograft
- isograft
- allograft
- xenograft
What are autografts?
- transplant self tissue
- burn victims, bone reconstruction, bypass
What are isografts?
-transplant tissue from a genetically identical individual
What are allografts?
-another person, same species different genes
What are xenografts?
- transplant tissues between species
- primate kidneys, heart; pig skin, heart, valves
What are the 3 general mechanisms of graft rejection?
- hyperacute
- acute
- chronic
What is graft vs host disease?
-bone marrow and hematopoietic stem cell transplants have the risk of transferring T cells from the donor to the recipient resulting in the disease
What is the paradox of graft vs host disease?
- donor T cells are needed for bone marrow engraftment and to prevent malignancy
- but donor T cells cause GvH disease
