Nelson-Immune Diseases Flashcards
What is an autoimmune disease?
An immune mediated inflammatory disease>
immune reactions to self antigens>
tissue and cell injury
What are the mediators of autoimmune disease?
Autoantibodies
Immune complexes
T lymphocytes
Autoimmune disease is d/t the loss of….
self tolerance
What is self tolerance?
Unresponsiveness when a lymphocyte is exposed to an antigen
What is the difference between central tolerance and peripheral tolerance?
Central (BM, thymus)
Peripheral tolerance (in the periphery, associated w/ anergy)
What is central tolerance?
killing immature self reactive T and B lymphocyte clones that recognize self antigens in BM/thymus
What is peripheral tolerance?
Irreversible inactivation of lymphocytes
suppression by T reg cells
deletion by activation induced cell death
What are the two factors that combined together lead to autoimmune disease?
- Inheritance of susceptibility genes–> breakdown of self tolerance
- Environmental triggers (infections/tissue damage)–> activation of self reactive lymphocytes
What are some of the ways that infections cause autoimmunity?
- Up-regulate the expression of co-stimulators–> breakdown of anergy–> activation of T cells for specific (self) antigen
- Molecular mimicry
- Infection–> tissue injury > release of self antigens > alteration of self antigens so they’re able to activate T lymphocytes
What is molecular mimicry?
Offending org can express antigens w/ same AA seq as self antigens–> IR so self antigens
What are examples of molecular mimicry?
Rheumatic heart disease: Ab against streptococccal proteins react w/ myocardial proteins–> myocarditis
EBV/HIV: polyclonal B cell activation > production of autoantibodies
What is clinical course of untreated autoimmune disease?
Directed at specific org/tissue–> specific disease
Directed at widespread antigen–> systemic/generalized disease
What are the general features of autoimmune disease?
once initiated is progressive
sporadic relapses/remissions
inexorable tissue damage if untreated
What is SLE?
Multisystem autoimmune disorder>
formation of autoantibodies (antinuclear) >
widespread multiorgan tissue injury)
What are some key features of SLE?
Acute or insidious
chronic-relapsing and remitting
Febrile illness
Injury to skin, joints, kdiney, serosal membranes
What causes SLE?
You can’t maintain self tolerance
Susceptibility genes + env triggers > loss of self tolerance and persistence of nuclear Ag> formation of Ag-Ab complexes> deposited in tissues> injury (type II hypersensitivity)
What is the potential complication of the presence of anti-phospholipid Ab in SLE?
False pos syphillis test
prolong partial thromboplastin time
Complications of hypercoaguable state (secondary anti-phospholipid Ab syndrome)
What is secondary anti-phospholipid Ab syndrome?
Venous/arterial thrombosis
spontaneous miscarriages
cerebral ischemia
What are the key clinicial features seen in SLE?
SOAP BRAIN MD S-serositis (inflammation of serious tissues of the body) O- oral ulcers A- arthritis P- photosensitivity B- blood disorders R-renal disease A- anti-nuclear ab pos I- immunologic abnormalities N- neurologic disease M- malar rash D- discoid rash
How does SLE cause renal disease?
Immune complex deposition in the glomeruli–> glomerular injury
How does SLE effect the skin?
immune complex deposition at the dermoepidermal junction
How is joint characterized in SLE (different from RA)?
non erosive
non-deforming small joint involvement
What sersitises are seen w/ SLE?
Pericarditis, endocarditits, pleuritits
What is a characteristic pathological findings of lupus nephritis?
wire loop lesions representing extensive subendothelial deposits of immune complexes
What is RA?
Chronic systemic inflammatory disorder
Primarily attacks joints>
inflammatory synovitis>
destruction of cartilage and ankylosis
What is the end result of RA?
stiffening/immobility of joints