Autoimmunity Flashcards
What is autoimmunity?
Response to self antigens = tissue damage due to breakdown in self-tolerance
How is autoimmunity mediated?
Autoantibodies and autoimmune T cells
Name 2 types of self-tolerance that may break down?
Central tolerance = in thymus filtering T cells that bind too strongly
T regs = dampen down the immune response
How is the effector mechanism against self antigens different to that of pathogens?
Similar mechanism but self antigens can not be eliminated so it is chronic
How is the chronic phase mediated?
Autoantibodies and autoimmune T cells
What is the type II antibody response? 2 examples autoimmunity
Antibodies against cell surface antigens
Haemolytic anemia
Pemphigus vulgarise (blistering of skin and mouth)
How can type II antibody response be recognised histologically?
Antibodies at surface
Type III antibody response?
Example
Antibody/antigen complexes that can deposit in tissues and cause inflammation
Rheumatoid arthiritis
Type IV antibody response?
Example x2
T cell mediated response
T1DM (beta cell destruction by T cells)
Rheumatoid arthiritis
SLE?
Cause?
What does it look like?
Systemic lupus erythematosus
Autoantibodies to common antigens like DNA
Wide spread red patches
Evidence there is a genetic and environmental component to autoimmune diseases?
Twin studies show concordance but not 100% and often different age of onset
How can MHC variants influence pathogens?
Antigen presentation and T cell activation
What evidence suggest autoimmune diseases are polygenic?
Specific mutations in HLA do cause a specific disease
How can infection affect autoimmune diseases?
Infection increase APC activation - more cytokines = more T cell activation = activate autoantibodies by bystander effect
Act as a adjuvant
Other than the bystander theory what mechanism can cause infection to lead to onset of disease?
Molecular mimcry
