12. Autoimmunity Flashcards
What is autoimmune reactivity?
Autoantibodies and/or autoreactive T cells are present
No detectable organ dysfunction or inflammation
What is autoimmune disease?
Adaptive immune system has caused inflammation and organ dysfunction in the absence of external stimuli
Give an example of molecular mimicry
Rheumatic fever
What infection precedes rheumatic fever?
Group A B haemolytic strep pharyngitis
How does molecular mimicry occur in rheumatic fever?
Anti-streptolysin antibodies mimic heart muscle, valves, joints and neurons
What are the clinical features of rheumatic fever?
Fever
Migrating arthritis
Destructive inflammatory lesions
Chorea
What set of criteria is used to diagnose rheumatic fever?
Jones criteria
Must have evidence of a strep infection
What are the major factors associated with rheumatic fever in Jones criteria?
Carditis
Polyarthritis
Rash
Sub cutaneous nodules
What are the minor features of the Jones criteria?
Fever
Arthralgia
History of Rheumatic fever
What are the long-term sequelae of rheumatic fever?
Valvular heart disease
Increased risk of endocarditis
Chorea
Give an example of how release of a sequestered antigen can cause autoimmunity
Trauma to one eye releases antigens, activated T cells attack both eyes
Give 2 examples of alteration of self
Lupus and hydralazine
Haemolytic anaemia and penicillin
How can superantigens cause autoimmunity?
Overwhelm regulatory mechanisms
How can infection of antigen presenting cells result in autoimmunity?
Activation of DCs can inappropriately produce a costimulation signal
Infected tissues can start producting MHC-2
What does ALPS stand for?
autoimmune lymphoproliferative syndrome
