Autoimmune diseases Flashcards
Tolerance
prevents our immune system from attack our own cells and tissues
Central tolerance
the elimination of strongly self-reactive T-cells or B-cell clones before they are allowed to mature
Peripheral tolerance
controls the activity of self-reactive T and B-cells in the tissues
Antigen sequestration
the retention of antigens in compartments w/o significant immune cell access that are immunologically privileged e.g. eye, brain
Regulatory T cells
a.k.a. T(REG)
~ a specific T-cell subset, they can be CD4+ or CD8+
Bystander suppression
when one APC engages several T-cells of different specificity and the T(REG) cell inhibits the activity of the other T-cells
Autoimmune diseases
caused by a failure of tolerance mechanisms which protect out tissue from destruction by our immune system
Name four examples of autoimmune disorders.
1) Type 1 Diabetes Mellitus
2) Myasthenia Gravis
3) Systemic Lupus Erythematous (SLE)
4) Multiple sclerosis (MS)
Type 1 Diabetes Mellitus
WHAT: organ-specific autoimmune disease affecting the pancreas where insulin-producing beta cells in the pancreas are attacked
EFFECT: increase blood-glucose levels
TREATMENT: daily insulin injections
Myasthenia Gravis
WHAT: organ-specific autoimmune disease were motor end plate cells of skeletal muscle cells are destroyed
CASUE: antibodies to Ach receptors trigger complemented-mediated lysis of the cell
EFFECT: progressive loss of muscle function
TREATMENT: immunosuppressants or cholinesterase inhibitors
Systemic Lupus Erythematous (SLE)
WHAT: systemic autoimmune disease where individuals produce autoantibodies to wide range of tissue antigens
EFFECT: butterfly rash on face, fever, kidney dysfunction, arthritis
TREATMENT: (mild illness) Antimalarials-Hydroxychloroquine
Multiple sclerosis (MS)
WHAT: auto-reactive T-cells attack the myelin sheath of nerve fibres and spinal cord
EFFECT: numbness, paralysis, loss of vision
TREATMENT: Corticosteroids (reduce nerve inflammation)
Causes of autoimmunity? (genetic)
~ multifactorial illnesses (genes + environment)
GENETIC FACTORS:
~ MHC variants
~ genes for immune cell surface proteins
~ genes for innate immune signalling factors
~ single mutation
Causes of autoimmunity? (environment)
~ hygiene hypothesis ~ mircobiome ~ sex hormones ~ Injury can reveal antigens from previously immunoprivileged sites ~ Molecular mimicry
Hygiene hypothesis
early stimulation of the immune system prevents autoimmunity
