Autoimmune Disorders Overview
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Questions and Answers

What is a primary feature of autoimmune disorders?

  • Improved tolerance to self-antigens
  • Reduced immune system activity
  • Increased production of immunoglobulins
  • Failure of self-tolerance (correct)

    • Which of the following mechanisms is commonly associated with autoimmune diseases?

  • Decrease in cytokine signaling
  • Inhibition of autoantibody production
  • Development of autoantibodies (correct)
  • Increased immune tolerance

    • What aspect is recommended for early treatment strategies for autoimmune disorders?

  • Complete physical and mental rest (correct)
  • Continual physical exertion to boost immune response
  • High protein diet without vitamins
  • Use of immunosuppressive therapies immediately

    • Which therapeutic strategy is focused on in the treatment of autoimmune disorders?

    <p>Dampening the aberrant immune response</p> Signup and view all the answers

    What is suggested as a physical treatment method in early therapies for autoimmune conditions?

    <p>Re-education of capillary circulation</p> Signup and view all the answers

    What is a major barrier to the successful grafting of embryonic stem cells?

    <p>Alloantigenicity and rejection by the recipient's immune system</p> Signup and view all the answers

    How can induced pluripotent stem (iPS) cells be generated?

    <p>By transduction of specific genes into adult somatic cells</p> Signup and view all the answers

    What is a potential benefit of using iPS cells for tissue repair?

    <p>They can be derived from the patient's own somatic cells, minimizing rejection</p> Signup and view all the answers

    What innovative approach is being explored to enhance the compatibility of embryonic stem cells for transplantation?

    <p>Removing MHC genes using CRISPR-Cas9 technology</p> Signup and view all the answers

    What is the significance of pigs with a record number of modified genes in the context of organ transplantation?

    <p>They provide organs for experimental transplants in nonhuman primates</p> Signup and view all the answers

    What does a positive tuberculin skin test indicate?

    <p>Previous or active tuberculosis infection</p> Signup and view all the answers

    In the context of immunologic diseases, what is the main goal of current therapeutic approaches?

    <p>Reducing immune activation and harmful autoimmune reactions</p> Signup and view all the answers

    Which autoantibodies are primarily produced in 80% of rheumatoid arthritis patients?

    <p>Rheumatoid factors targeting the Fc region of human IgG</p> Signup and view all the answers

    What type of hypersensitivity reaction is characterized by induration following exposure to PPD?

    <p>Type 4 hypersensitivity reaction</p> Signup and view all the answers

    Which component is NOT commonly targeted by current therapeutic agents for autoimmune diseases?

    <p>Mass cell mediators</p> Signup and view all the answers

    What type of solution is PPD when used for testing tuberculosis exposure?

    <p>Protein antigen</p> Signup and view all the answers

    What cells are primarily involved in the hypersensitivity reaction after PPD injection?

    <p>T cells and macrophages</p> Signup and view all the answers

    Which of the following is NOT an outcome of treating rheumatoid arthritis with anti-TNF-α agents?

    <p>Complete eradication of the disease</p> Signup and view all the answers

    Which type of hypersensitivity reaction is uniquely associated with allergic diseases?

    <p>Type I hypersensitivity</p> Signup and view all the answers

    What defines autoantibodies that act as receptor agonists?

    <p>They mimic the natural ligand and activate receptor signaling.</p> Signup and view all the answers

    How do autoantibodies that are receptor antagonists differ from agonists?

    <p>They prevent the natural ligand from binding to the receptor.</p> Signup and view all the answers

    Which of the following diseases is caused by autoantibodies against the TSH receptor?

    <p>Graves' disease</p> Signup and view all the answers

    What role do antibodies against streptococcal cell-wall antigens play in rheumatic fever?

    <p>They cause autoimmune reactions by cross-reacting with heart tissue.</p> Signup and view all the answers

    What kinds of immune mechanisms contribute to tissue injury in hypersensitivity diseases?

    <p>Both cell-mediated and humoral mechanisms.</p> Signup and view all the answers

    What characterizes type II hypersensitivity reactions?

    <p>Direct damage to cells by antibodies.</p> Signup and view all the answers

    What is a primary outcome of T3 and T4 action in thyroid hormone regulation?

    <p>Inhibition of TSH production.</p> Signup and view all the answers

    What is a consequence of autoAbs binding to the TSH receptor in Graves' disease?

    <p>Increased independence from TSH for hormone production</p> Signup and view all the answers

    In myasthenia gravis, what primary effect do autoAbs have on muscle acetylcholine receptors?

    <p>Cause endocytosis and degradation of receptors</p> Signup and view all the answers

    What role do antibodies play when they function as agonists?

    <p>They stimulate receptor activity</p> Signup and view all the answers

    What is the typical characteristic of autoantibodies in autoimmune diseases?

    <p>They target cell-surface receptors or tissues</p> Signup and view all the answers

    Which mechanism does NOT contribute to the destruction of RBCs in autoimmune hemolytic anemia?

    <p>Enhanced production of erythropoietin</p> Signup and view all the answers

    What is the primary effect of autoAbs on neuromuscular junctions in myasthenia gravis?

    <p>Reduce the number of functional acetylcholine receptors</p> Signup and view all the answers

    AutoAbs that act as antagonists do what to cell-surface receptors?

    <p>Block receptor function</p> Signup and view all the answers

    Which condition is associated with antibodies specifically targeting acetylcholine receptors?

    <p>Myasthenia gravis</p> Signup and view all the answers

    Study Notes

    Autoimmune Disorders

    • More than 80 known autoimmune disorders exist
    • Affect a wide range of organ systems
    • Both cellular and humoral immune components can be involved

    Common Autoimmune Mechanisms

    • Each autoimmune disease likely has specific triggers and pathogenesis
    • Common mechanisms include development of autoantibodies and aberrant cytokine signaling
    • Therapeutic strategies focus on suppressing the abnormal immune response

    Early Treatment Strategies

    • Recommended treatment for autoimmune disorders in 1883 included:
      • Complete physical and mental rest (bed rest)
      • Good nourishing diet with plenty of vitamins and iron
      • Living in the best hygienic conditions
      • Elimination of sepsis
      • Physical and orthopedic treatment
      • Analgesics to promote sleep and relieve pain (aspirin, phenacetin, caffeine)

    Comparing Hypersensitivity Reactions

    • Allergic diseases, transplantation diseases, and autoimmune diseases share effector mechanisms corresponding to type II, III, and IV hypersensitivity reactions
    • Allergic diseases are unique in their reliance on IgE-mediated type I hypersensitivity reactions

    Autoantibodies and Heart Tissue

    • Antibodies produced in response to bacterial infection can cross-react with heart tissue, leading to rheumatic fever

    Infections and Autoimmunity

    • Certain infections are linked to the onset of autoimmunity

    Antibody-Mediated Disease

    • Antibodies can act as receptor agonists, mimicking the natural ligand and activating signaling pathways
    • Antibodies can act as receptor antagonists, blocking the natural ligand from binding and preventing signaling

    Examples of Antibody-Mediated Diseases

    • Graves' disease is caused by autoantibodies that mimic TSH, stimulating thyroid hormone production
    • Myasthenia gravis is caused by autoantibodies that block acetylcholine receptors, leading to muscle weakness

    Cell- or Tissue-Specific Antibodies

    • Antibodies responsible for cell or tissue-specific diseases are typically autoantibodies, but can also be specific to microbes

    Mechanisms of Autoimmune Hemolytic Anemia

    • Red blood cells (RBCs) can be destroyed by several mechanisms in autoimmune hemolytic anemia:
      • Phagocytosis by macrophages in the spleen through Fcγ receptors or complement receptors
      • Complement activation, leading to lysis of RBCs
      • Antibody-mediated agglutination, leading to blood vessel blockage and tissue damage

    Type 4 Hypersensitivity Reaction

    • Also known as delayed-type hypersensitivity (DTH)
    • Involves T cells and macrophages
    • Example: Tuberculin skin test (TST)

    Cytokine Antagonists

    • Some cytokine antagonists are in clinical use or undergoing trials for treating autoimmune diseases

    Therapeutic Approaches

    • Therapeutic approaches for autoimmune disorders aim to reduce immune activation and the harmful consequences of autoimmune reactions

    Systemic Lupus Erythematosus (SLE)

    • Autoantibodies against nuclear antigens are characteristic
    • Activation of complement and inflammation contribute to disease pathogenesis

    Rheumatoid Arthritis (RA)

    • 80% of RA patients produce antibodies against the Fc region of human IgG, known as rheumatoid factors
    • Rheumatoid factors contribute to inflammation in the joints

    Treatment Effects of Anti-TNF-α in RA

    • Anti-TNF-α therapy can reduce inflammation and improve symptoms in RA

    Induced Pluripotent Stem (iPS) Cells

    • iPS cells can be derived from adult somatic tissues and can be used to repair tissues with limited regenerative capacity
    • iPS cells are less likely to be rejected by the immune system compared to embryonic stem cells

    Genetically Modified Pigs for Transplantation

    • Pigs have been genetically modified to reduce immunogenicity and improve their suitability as organ donors for humans
    • Pigs with multiple gene modifications are being used in experimental transplantations in non-human primates

    Future of Organ Transplantation

    • Genetically modified pigs hold promise as a source of organs for humans, potentially addressing organ shortages

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    Immunologic Tolerance and Autoimmunity Review Part 2 PDF

    Description

    Explore the complexity of autoimmune disorders, including their mechanisms, treatment strategies, and the comparison with hypersensitivity reactions. This quiz delves into the specific triggers and pathogenesis of these diseases as well as historical treatment approaches.

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