pathophysiology Flashcards
autoimmunity: recognise the mechanisms of autoimmunity and how they apply to autoimmune rheumatic disease; recall major autoantibody systems which are used in the diagnosis and management of rheumatological disease
key auto-antibodies in rheumatoid arthritis
rheumatoid factor, anti-cyclic citrullinated peptide antibody
key auto-antibodies in systemic lupus erythematosus
antinuclear antibodies, anti-double stranded DNA antibodies
key auto-antibodies in diffuse systemic sclerosis
anti-Scl-70 antibody
key auto-antibodies in limited systemic sclerosis
anti-centromere antibodies
key auto-antibodies in dermato/polymyositis
anti-tRNA transferase antibodies
key auto-antibodies in mixed (overlap) connective tissue disease
anti-U1-RNP antibodies
where are antinuclear antibodies present
all systemic lupus erythematosus cases, but not specific to it
what are anti-double stranded DNA antibodies specific for
specific for systemic lupus erythematosus
what does serum level of anti-double stranded DNA antibodies in systemic lupus erythematosus correlate with
disease activity, so can change over time
what are antinuclear antibodies reacting to
nuclear antigens
what happens if antinuclear antibodies test is positive
further tests will be performed to determine which type of antinuclear antibody it is, including anti-double stranded DNA antibodies and anti-Sm (both more specific to SLE)
what do patients with systemic lupus erythematosus commonly have low and high levels of during high disease activity
producing more immune complexes, so measure complement and antibody response: low complement levels (can see it declining as patient becomes more unwell as complement used up), high serum levels of anti-double stranded DNA antibodies (can see it rising as patient becomes more unwell)
pathogenesis of systemic lupus erythematosus
apoptosis leads to translocation of nuclear antigens to membrane surface -> impaired clearance of apoptotic cells results in enhanced presentation of nuclear antigens to immune cells (e.g. Sm) -> B cell autoimmunity -> tissue damage by antibody effector mechanisms e.g. complement activation and Fc receptor engagement
