immune disease 2 (W12) Flashcards
association between autoimmune disease?
having one increases likeliness for having another
how can autoimmunity start
self antigens become modified
microbial antigens resemble self
hidden antigens can be exposed by damage
inflammation breaks anergy (stimulating bystander lymphocytes)
susceptibility genes for autoimmunity and example diseases?
MHC alleles (AS, type 1 diabetes, SLE, RA)
tissue targeted autoimmunity diseases?
type 1 diabetes
MS
graves’ disease
myasthenia gravis
primary biliary cholangitis
multisystem autoimmunity diseases?
SLE
RA
2 antibody mediated reactions (damaging)
binding of antibody to own cells
hypersensitivity reaction
hypersensitivity reaction example?
haemolytic anaemia: antibodies bind to red blood cells (due to molecular mimicry of recent viral infection) or antibody binds to specific drug-protein complex on red cell surface. antibodies tag these cells for removal even though they are healthy
disease examples where autoantibody binds to cell surface receptor? explain?
graves disease - stimulates TSH receptor leading to hyperthyroidism
Myasthenia gravis - blocks Ach receptor leading to neuromuscular weakness
what occurs if transfused blood is not the right type
anti-A or anti-B antibodies bind to foreign red cells, induce complement, causing red cell lysis, inflammation in the circulation, haemolysis and intravascular coagulation. System wide cytokine storm and shock.
which blood group can be given to anyone? why?
O - lacks A and B antigens
which blood group can receive any blood type? why?
AB - lacks A and B antibodies
rhesus reaction?
IgG response to protein. rhesus negative (RhD-) mother has RhD+ baby, risk of mother being exposed to RhD+ blood cells. problem for next pregnancy as now has anti-RhD antibodies that will react to future RhD+ babies.
damage from antibody binding extracellular targets
antigen-antibody complexes become saturated in the circulation, leads to deposition (small blood vessels in particularly joints, skin). Complement usually breaks these up but it can exceed their capacity.
unsensitised vs sensitised hypersensitivity?
unsensitised - haven’t been exposed to allergen protein
sensitised - has been expensed to allergen protein before
chronic antigen exposure - autoimmunity disease example?
SLE - nuclear autoantigens from dying cells
chronic antigen exposure - chronic infection example?
infectious endocarditis
damage from cytotoxic T cell killing - autoimmunity example?
type 1 diabetes:
CTL kill pancreatic islet beta cells (target insulin-related peptides)
damage from cytotoxic T cell killing - hypersensitivity examples?
coeliac disease
allergic contact dermatitis
coeliac disease?
sentinel intraepithelial CD8 T cells kill intestinal epithelium stressed by cytokines from Th1 cells sensitised to modified dietary gliadin (idk what this means)
allergic contact dermatitis?
manifests 2-4 days after re-exposure. red plaques, vesicles, acute oedema, evolving to dry scaly skin. effector memory T cell reaction to neoantigen. sensitised cytotoxic T cells kill keratinocytes that have bound to an allergen (eg nickel from bracelet, topical drugs etc).
damage from Th cell activation of macrophages - example disease?
some sarcoid cases
