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30 Cards in this Set
- Front
- Back
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What is autoimmunity?
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An immune reaction against self-antigens
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What is the normal human's lack of response to self antigens called?
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Immunologic tolerance
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Are autoantibodies always pathologic?
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No, they can be found circulating inocuously in older people
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What are the 2 general types of self-tolerance?
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1. Central tolerance
2. Peripheral tolerance |
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What is Central tolerance?
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The deletion of self-reactive Tcells and Bcells during maturation in the thymus and bone marrow.
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What is peripheral tolerance?
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The deletion or anergy of lymphocytes that recognize self-Ag in peripheral tissues.
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How does deletion of self-recognizing lymphocytes occur?
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Via apoptosis
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How does anergy of self-recognizing lymphocytes occur?
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Via lack of B7 on the self APC, which renders the Tcell nonfunctional and unresponsive.
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What is antigen sequestration?
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Hiding antigens from the immune system because the tissues are not in communication with blood and lymph
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What are 3 immune-privileged sites?
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-Brain
-Eye -Testes |
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What happens if certain trauma or infection causes immune-privileged tissues to release their proteins?
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Autoimmune response that causes inflammation and damage.
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What are genetic factors that influence autoimmunity?
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Susceptibility genes
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What is one of the best defined susceptibility genes for autoimmunity?
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HLA
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What is the B27 HLA allele associated with?
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Ankylosing spondylitis
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What is the DR4 HLA allele associated with?
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Rheumatoid arthritis
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What is the DR3 HLA allele associated with?
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sjogren syndrome
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What is the DR3/DR4 HLA allele associated with?
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Type I Diabetes
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What populations have increased prevalence of autoimmunity due to hormonal factors?
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-Women
-Those with klinefelters syndrome (extra X ch') |
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What hormone confers protection against autoimmunity?
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Testosterone
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2 mechanisms by which infections induce autoimmunity:
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1. Upregulated B7/CD28 on host cells
2. Cross-reacting of a microbial antigen with self-reactive Tcells; after clonal expansion then they attack the self proteins. |
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What are the 4 categories of antinuclear antibodies?
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-Anti-DNA
-Anti-histone -Anti-nonhistone proteins bound to DNA -Antinucleolar |
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What type of test is an ANA assay?
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An immunofluorescence assay
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For what disease is the ANA most sensitive?
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SLE
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What ANA titer will most individuals have?
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1:40 (most)
1:80 (a few) 1:320 (very few) |
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So what would you definetely call an abnormal ANA assay?
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>1:40 (number smaller than 40)
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Once an ANA test returns positive, what is the next step in diagnosing autoimmune diseases?
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Assaying for specific antibodies
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What are 2 specific Ab's diagnostic for SLE?
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Anti-ds-DNA
Anti-Sm |
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What is the specific Ab diagnostic for disseminated lupus?
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Anti-histone
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What are 2 specific Ab's diagnostic for Sjogren's syndrome?
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Anti-RNP-SS-A (Anti-Ro)
Anti-RNP-SS-B (Anti-La) |
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What is the specific Ab diagnostic for limited scleroderma?
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Anticentromere
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