Autoimmunity and Autoimmune disease Flashcards
Which two mechanisms give rise to immunological tolerance?
Central control: in the thymus
Peripheral control: in the tissues
What mediates peripheral control mechanisms?
T-regulatory (Th17) cells, via IL-17
- Th17 cells inhibit expression of the immune response to prevent over-reactivity of the immune system
Give three ways in which Th17 cells modulate the immune reponse in the tissues
Clonal deletion
Clonal ignorance
Suppression of lymphocyte activation/effector functions
Define Autoimmunity
Physiological autorecognition with secondary epiphenomena
Define Autoimmune Disease
Immune response contributing directly to tissue/organ damage. Often exist as a mix of different autoimmune reactions. Environment and genetics play key roles.
Give two examples of infections which can trigger autoimmune disease
Klebsiella pneumoniae can trigger ankylosing spondylitis
Coxsackievirus B can trigger diabetes mellitus type I
Which type of cells are implicated in cell-mediated autoimmune disease?
T lymphocytes
Natural Killer cells
Give four examples of cell-mediated autoimmune diseases, and briefly describe the mechanisms behind them
Type I DM - failure of T-reg cells
Crohn’s disease - Th1 cells involved
Psoriasis - autoreactive Tcells against skin associated antigens
Coeliac disease - Tcells sensitised to gluten attack gut lumen by mistake
Describe the mechanism behind Type I Diabetes Mellitus
Failure of T-reg cells allows the survival of Tcells which are autoreactive against pancreatic islet cell antigens (AntiGAD antibodies), leading to destruction and non-production of insulin
Which antibodies are involved in T1DM?
AntiGAD antibodies (against pancreatic islet cell antigens)
Give two examples of antibody-mediated autoimmune disease and briefly describe the mechanisms
Myasthenia gravis
Goodpasture’s syndrome - autoimmunity against type IV collagen
Give an example of an autoimmune disease mediated by immune-complexes
Which antibodies are involved?
Systemic lupus erythematosus
Auto-antibodies against DNA (anti-nuclear antibodies)
Give four examples of autoimmune diseases mediated by molecular mimicry mechanisms?
Rheumatic fever
Hashimoto’s thyroiditis
Myasthenia gravis
Grave’s disease
Give four autoimmune diseases which are organ-specific
Autoimmune thyroid diseases - Grave's - Hashimoto's Myasthenia gravis Pernicious anaemia Diabetes mellitus (type I)
Give four autoimmune diseases which are non-organ specific
SLE
RA
Systemic sclerosis
Systemic vasculitis
