autoimmunity Flashcards
(28 cards)
what must happen in the central and peripheral tolerance mechanisms in order for them to be breachedinto autoimmunity
central the autoreactive ly,phocytes must not be deleted in the BM and Thymus and periphery the normal inhibitory mechanisms fail must fail.
what are the factors that influence development of an autoimmune disease
abnormalities of lymphocytes and APC’s, genetic predisposition, and microbial infection.
what causes the tissue damage in an autoimmune disease
Auto-reactive CTL’s circulating autoantibodies, and immune complexes.
what is vertical transmission of an autoimmune disease
if they are IgG antibodies then can cross the placenta and cause symptoms in the child but this is usually reversible once the child is born within a few months can cause organ damage.
what is the sequestered antigens theory
where your privileged areas such as eye brain and genitals, if they are damaged and released into the blood they will cause auto immunity because we do not have those proteins available to induce tolerance.
what is the microbes theory of autoimmunity
other organisms such as virus have enough similarity to self peptides and then after the virus is gone we still attack self. Known as molecular mimecry.
what is the theory of inapproproate expression of MHC
some cells can express class 2 MHC when they are not supposed to and will activate the T cells, also genes near the HLA site could be causing this autoimmune disease as well. Some t cells will bind with positive self but not with high enough affinity for negative selection for destruction.
how does hemolytic anemia occur
RBC antibodies produced against RBC membrane proteins, this cause RBC lysis and anemia intrascular hemolysis or can lead to opsiniation and removal of RBC by phagocyte cells in spleen extravascular hemolysis.
what is good pasture syndrom
autoantibodies against type 4 collagen most damage in the lung and the kidneys, smooth ribbon like apearance in staining
what is pernicios anemia
autoantibodies to intrinisic factor or gastric parietal cells lowers vit B12 absorption and leads to anemia
what is hashimotos thyroidits
hypothyroid state agaist thyroid autoreactive against thyroid gland proteins
idiopathic throbocyopenia purpura ITP
Treatment?
ITP is caused by anutoantiboides against the platelet membrane protiens causes purple skin lesions due to epidermal hemorrhage IVIG can prevent destruction
IV immunoglobulin administration - prevents destruction by Fc receptor-mediated binding and removal of platelets
what is vitiligo
depigmentation of skin by destruction of melanocytes
graves disease
autoantibodies agasnt TSH receptor stimulate secretion of thyroid hormones causes hyperthyroidism
what is myasthenia gravis
antibodies against the acetocholine receptors leads to lack of nerve impulse reception.
type one diabetias
beta islets antibodies causing CTK to kill it
multiple sclerosis
causese demyelinatting of CNS, takes 1-2 decades to see it, relapsing remitting or progressive form, therapies include interferion Beta 1B, steroids and beta 1a
Produce IgG specific to myelin, activates complement
Macrophages attract to inflammation, secrete NO –> destroys nerve fibers
lupas what is it
Stystemic disease. Broad loss of regulatory control that sustains self toleranc. Antibodies against DNA,RNA proteins and ribonucleoporteins , most common organs skin joints and kidney, more common in women.
Tissue damage via T3HS, RBC/WBC lysis via complement (T2HS)
Principle danger - RBC w/CR1 binding C3b and C4b, forming complexes, passing through kidneys
what gives you a predisposition of lupas
gentitcs
some drugs can cause reversible lupas
immunologic factors: loss of B cell self-tolerance due to B cell hyperactivity, excessive T-helper activity and/or lack of appropriate T suppressor activity
what is rheumatoid arthritis
destruction of the joints cartilage and inflammation femals more common, closer to type 4 sensitivity, IgM/IgG to Fc protion of IgG makes an immune complex. Cause also effect lungs and heart. Can be treated by etanercpt remose IgG1 antiobdy, Infliximad gets rid of TNF
what is sjogrens syndrome
causes dry eyes and mouth desctuciton of lacrimal and salivary glands,
40% chance of lymphoid malignancies
Occurs alone or with RA or SLE
what is scleroderma
hypersensitivity to collagen
Pt’s also have antinuclear Ab, though role uncertain
T cells infiltrate dermis –> release IL-1, TNFalpha, lays more collagen down, cycles
polymyositis and dermatomoysitis
muscle injury possible by CD4 and CD8 t lymphocites in muscle, causes a skin rash . Could be caused by coxsackie b virus
1/4 have Ab to tRNA synthetase (diagnostic)
what are some of the therapies for autoimmune diseaes (5)
Corticosteroids (prednisone) - antiinflammatory, causes bone mineral loss, weight gain, diabetes…
Azathioprine and cyclophosphamide: cytotoxid drugs interfering with DNA synthesis - eliminates diving lymphocytes
Immunosupression - cyclosporine and tacrolimus - blocks transcription of IL-2, but nephrotoxic
Plasmapheresis - remove Ag-Ab complex. Short term
Antagonism of TNF-alpha: Infliximab (humanized anti-THF monoclonal Ab); Etanercept - binds TNF; both good anti-inflammatories
