Autoimmunity Flashcards
7 pages - lecture 10
define autoimmunity
the immune system attacks host components to cause pathological change. can be chronic and debilitating. considered a failure of self tolerance
4 organ specific autoimmune diseases
1 - hashimoto's thyroiditis 2 - grace's disease 3 - pernicious anaemia - stomach 4 - type 1 diabetes - pancreas. may be as they are well vascularised and make organ specific proteins
give 3 non organ specific autoimmune diseases
1 - scleroderma - skin
2 - systemic lupus erythematosis
3 - rheumatoid arthritis
give the three types of autoimmuneity and their analogous hypersensitivity type
1 - direct antibody mediated effects - type 2 hypersensitivity
2 - immune complex mediated effects - similar to type 3
3 - T cell mediated - cellular
describe grave’s disease
type 1 - autoantibodies to the TSH receptor
- this stimulates unregulated synthesis of thyroid hormones as it decouples it from negative feedback on to the pituitary gland
describe myasthenia gravis
type 1 - autoantibodies to the ACh receptor
block ACh binding and cause receptor downregulation.
what is rheumatic fever ?
an example of direct tissue pathology following antibody binding. often follows a Streptococcus pyogenes infection.
cause of vasculitis?
deposition of autoantibody-antigen complexes
describe systemic lupus erythematosus
type 2 - patients have a variety of anticytoplasmic and antinuclear autoantibodies.
causes characteristic butterfly rash on the face.
can have significant complement depletion.
complement deficiencies that impair immune clearance are predisposing.
more common in african and asian women.
mechanisms of type 3, T cell mediated autoimmunity?
CD8 cytotoxicity, direct destruction by TNF, macrophage recruitment and bystander killing, induciton of apoptosis by Fas ligand.
what’s an EAE rat?
experimental autoimmune encephalomyelitis
- immunise rate with myelin basic protein in complete Freund’s adjuvant. Th1 CD4 cells specific to MBP are isolated and can cause disease if injected into another animal.
EAE resembles multiple sclerosis
what is autoimmune haemolytic anaemia?
autoantigen - Rh blood group antigens
consequence - destruction of RBC
what is goodpasture’s syndrome?
autoantigen - collagen type 4
consequence - glomerulonephritis
what is grave’s disease?
autoantigen - TSH receptor
consequence - hyperthyroidism
what is myasthenia gravis?
autoantigen - ACh receptor
consequence - progressive weakness
what is subacute baterial endocarditis?
autoantigen - bacterial antigen
consequence - glomerulonephritis
immune complex
what is SLE?
autoantigen - DNA, histones, ribosomes, snRNP, scRNP
consequence - glomerulonephritis, vasculitis, arthritis
immune complex
what is rheumatoid arthritis?
autoantigen - synovial joint antigens
consequence - joint inflammation and destruction
immune complex
what is multiple sclerosis?
autoantigen - myelin basic protein proteolipoprotein
consequence - brain degeneration and paralysis
autoimmune disease associated with HLA B27?
ankylosing spondylitis - RR of 90
goodpasture’s syndrome - RR of 10
autoimmune disease associated with DR2?
MS - RR of 5
autoimmune disease associated with DR3?
grave’s - RR 4
myasthenia gravis - RR2.5
SLE - RR 6
autoimmune disease associated with DR3/4?
T1D - RR3
autoimmune disease associated with DR4?
Rheumatoid arthritis - RR 4