Autoimmunity Flashcards
1
Q
type II autoimmunity
A
analogous to type II hypersensitivities in that they are mediated by antibodies that are specific for determinants of cell surfaces structures/extracellular matrix
2
Q
type III autoimmunity
A
are analogous to type III hypersensitivities because they are mediated primarily by IgG and result in immune complex disease
3
Q
type IV autoimmunity
A
analogous to type IV hypersensitivities because they are mediated by T cells. The T cells are specific for self determinants
4
Q
T/F the eyes and testes are functionally separated from the rest of the body in respect to release of antigens and unless there is injury to that site T cells are never presented with these antigens and they are never available for thymic selection
A
true
5
Q
Autoimmune hemolytic anemia (II)
A
- results from priming of an acquired antibody response to surface determinants of RBCs
- response mediated by IgG and some IgM
- activates classical complement cascade and MAC
- lead to phagocytosis/destruction of RBC’s
- symptom: anemia
- Dx- direct coombs test
- treat: corticosteroids
6
Q
Autoimmune idiopathic thrombocytopenic purpura (II)
A
- results in low platelet counts and damaged RBCs (called microangioplastic hemolytic anemia)
- caused by IgG that binds to and inhibits the function of an enzyme that cleaves von Wildebrand factor
- results in platelet aggregation and depletion from the system (abnormal platelet adhesion can cause damage to the RBCs)
- also affects the liver, kidneys, and brain
- purpura present due to reduced ability to clot
- dx: observation of microangioplastic hemolytic anemia
- treat: plasma exchange with plasma from healthy donors
7
Q
Goodpasture’s syndrome (II)
A
- caused by an IgG response to type-IV collagen
- inflammation mediated by the classical complement cascade (and then the alternative pathway) and phagocytes causes tissue damage
- PROGRESSIVE KIDNEY DYSFUNCTION culminating in glomerulonephritis
- loss of appetite, fatigue, weakness, decreased kidney fun
- dx: measurement of glomerular basement membrane-specific antibodies (anti-GBM)
- treat: plasma exchange and with anti-inflammatory drugs
8
Q
Schleroderma (II)
A
- an IgG-mediated autoimmune disease that results in damage to the vascular endothelium of arteriole and smooth muscle cells that results in replacement of damaged tissue with collagen
- symptoms are mediated by ANA (anti-nuclear Abs), ATA (anti-topoisomerase Abs), and ACA (anti-centromere Abs), all IgGs
- skin hardening and damage to liver kidney and brain
- treat: drugs that promote blood flow to extremities
9
Q
Acute rheumatic fever (II)
A
- molecular mimicry
- A normal IgG response to group A Streptococcus pyogenes (GAS) infection cross reacts with normal host tissue
- damage to the heart is mediated by cross-reactive IgG
- results in myocarditis from scarring of the heart
- chest pain, shortness of breath, fever, joint pain
10
Q
Pemphigus vulgaris (II)
A
- chronic painful skin blistering
- is mediated by IgG specific for desmoglein 1 and 3, and it results in loss of cohesion in keratinocytes.
- dx: : immunofluorescent staining to identify IgG4 Ab bound to tissue from a punch biopsy
- treat: corticosteroids and other anti-inflammatories; ritiximab (CD20-specific mAb)
11
Q
Grave’s disease (II)
A
- thyroid stimulating hormone receptor (TSH receptor)-specific IgG antibodies cause over-production of thyroid hormone because the antibodies serve as receptor agonists
- bulging eye syndrome (with a characteristic stare) is hallmark; also: enlarged thyroid, heat intolerance, nervousness, irritability, weight loss, and moist skin
- pregnant mother will pass her IgG on to her child and the child will need plasmaphoresis (plasma exchange)
12
Q
Myasthenia Gravis (II)
A
- an IgG response to acetylcholine receptors on muscle cells that antagonizes normal signaling at the neuromuscular junction
- cause endocytosis and destruction of receptors
- typically begin with facial muscles, and especially muscles of the eyes and eyelids. These patients often present with diplopia (double vision) and ptosis (sagging eyelids). Over time, the condition progresses to generalized muscle weakness
- treat: anti-inflammatory drugs and pyridostigmine
13
Q
Subacute Bacterial Endocarditis (III)
A
- condition mediated by IgG that is made in response the the normal flora organism Streptococcus viridans that have colonized damaged heart valves
- colonizes heart valves that have already been damaged (e.g. rheumatic fever, congenital condition
- IgG specific for determinants of this bug bind to the bacteria, promoting recognition of the immune complex by phagocytes as well as initiation of the classical complement cascade
- causes further damage to heart valves and myocardium
- is considered an immune complex “hypersensitivity” or immune complex autoimmune disease because the inflammation results from recognition of immune complexes
14
Q
Mixed essential cryoglobulinemia (III)
A
- characterized by production of cryoglobulins (immunoglobulins that become insoluble at reduced temperatures; sometimes they are only composed of light chains (Bence-Jones proteins))
- similar to rheumatoid factor in that they have specificity for the Fc regions of antibodies and can cause immune complex disease
- hep B
- Meltzer’s Triad(purpura, arthralgia and myalgia)
15
Q
Systemic lupus erythematosus (III)
A
- autoimmune disease that is mediated by autoantibodies (IgG) that are specific for several self macromolecules, including dsDNA, histones, and ribosomes
- inflammatory response leads to tissue damage and release of auto antigens
- immune complexes are formed in the extracellular spaces and in the circulation
- vasculitis, kidney damage progressing to glomerulonephritis, and even neurological dysfunction due to vasculitis in the brain
- fever, malaise, joint pain, myalgias, and fatigue (kidney dysfunction in advanced cases)
- anti-inflammatory drugs
- wolf-face/butterfly rash
- blood in ruin, high titers anti-histone Abs, high titer anti-ribosome Abs, positive direct Coomb’s(will have anemia), and reduced compliment C1 levels
