Autoimmunity - Chapter 19 (young)
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Questions and Answers

What does epitope spreading refer to?

  • The process of autoantigen elimination
  • The immediate reaction to a single antigen
  • A decrease in immune response to self-antigens
  • The evolution of immune response to include further epitopes (correct)

    • Which autoimmune disease is characterized by systemic production of anti-self antibodies?

  • Systemic Lupus Erythematosis (correct)
  • Rheumatoid Arthritis
  • Insulin-Dependent Diabetes Mellitus
  • Multiple Sclerosis

    • What initiates autoimmune disease in the context of immune system function?

  • Escape of autoreactive T/B cells from central tolerance (correct)
  • The immune system malfunctioning without any triggers
  • Damaged immune regulation due to external factors
  • Genetic mutations in T-helper cells only

    • What is a common characteristic of autoimmune diseases?

    <p>Aberrant immunological response against self organs</p> Signup and view all the answers

    What is a key requirement for autoimmune disease to develop?

    <p>Escaped autoreactive cells encountering antigen in the periphery</p> Signup and view all the answers

    Which mechanism can lead to the initiation of autoimmune disorders following an infection?

    <p>Molecular mimicry involving pathogens</p> Signup and view all the answers

    What primarily causes damage in Systemic Lupus Erythematosis?

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

    What does the failure of peripheral tolerance mechanisms indicate in the context of autoimmunity?

    <p>Inability to regulate self-reactive immune responses</p> Signup and view all the answers

    Which statement accurately describes Rheumatoid Arthritis?

    <p>It involves autoantibodies against joint proteins and rheumatoid factor</p> Signup and view all the answers

    Which of the following is NOT a mechanism mentioned in connection with autoimmune disease development?

    <p>Antigen-presenting cells inducing tolerance</p> Signup and view all the answers

    What is the role of autoreactive T cells in Multiple Sclerosis?

    <p>They destroy the myelin sheath surrounding nerve cells</p> Signup and view all the answers

    Which of the following conditions is NOT characterized by Type III hypersensitivity?

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

    What is the role of regulatory T cells in autoimmune diseases?

    <p>To suppress inappropriate immune responses</p> Signup and view all the answers

    How does cross-presentation by dendritic cells contribute to autoimmunity?

    <p>By activating autoreactive T cells in a specific context</p> Signup and view all the answers

    Which factors contribute to the pathogenesis of Multiple Sclerosis?

    <p>Environmental and genetic components</p> Signup and view all the answers

    Which factor can be considered a defect in immune components related to the onset of autoimmunity?

    <p>Mutations in antigen-specific peptide generation</p> Signup and view all the answers

    What type of antibodies are associated with systemic symptoms in Systemic Lupus Erythematosis?

    <p>Anti-DNA antibodies</p> Signup and view all the answers

    What is the main cause of symptoms in autoimmune diseases?

    <p>Destruction of self tissues due to host response</p> Signup and view all the answers

    Which of the following statements best describes autoimmune disease?

    <p>It arises when the immune system attacks its own tissues due to loss of tolerance.</p> Signup and view all the answers

    What happens during infection-induced autoimmune diseases?

    <p>Infection can trigger autoreactive response that leads to chronic damage.</p> Signup and view all the answers

    What is a characteristic effect of the autoantibody in Graves' disease?

    <p>It stimulates unregulated overproduction of thyroid hormones.</p> Signup and view all the answers

    Which of the following is a genetic factor that may predispose individuals to autoimmune diseases?

    <p>HLA-B27</p> Signup and view all the answers

    In Myasthenia Gravis, what receptor is affected by the autoantibody?

    <p>Acetylcholine receptors</p> Signup and view all the answers

    What is a common approach for treating autoimmune diseases?

    <p>Untargeted schemes to downregulate the immune system</p> Signup and view all the answers

    Which treatment involves the removal of specific antibodies?

    <p>Plasmapheresis</p> Signup and view all the answers

    What is the consequence of autoantibodies blocking acetylcholine receptors in Myasthenia Gravis?

    <p>Loss of signaling and muscle function</p> Signup and view all the answers

    How do HLA-B27 carriers generally compare to non-carriers regarding autoimmune disease risk?

    <p>They may have a higher susceptibility to certain autoimmune diseases.</p> Signup and view all the answers

    Which of the following treatments is NOT typically aimed at downregulating the immune system?

    <p>Antibiotics</p> Signup and view all the answers

    What role do autoantibodies generally play in autoimmune diseases?

    <p>They block normal host receptors or mimic host components.</p> Signup and view all the answers

    What type of immune response do most treatments for autoimmune diseases aim to modify?

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

    Study Notes

    Autoimmunity - Chapter 19

    • Autoimmunity is present in all individuals to some degree, as self-reactive T cells and antibodies exist.
    • Autoimmune diseases occur when clinical pathology develops, either due to the immune system damaging tissues or due to regulation of the immune system becoming inappropriate.
    • Some mechanisms of autoimmune disease are well understood, while others are theoretical.
    • Factors include failure in central or peripheral tolerance, the role of regulatory T cells, and the immune system targeting the wrong target.
    • Prerequisites for autoimmune disease include: autoreactive T/B cells escaping central tolerance during development, the escaped autoreactive cells encountering antigen in the periphery, peripheral tolerance mechanisms failing, and the response causing damage.
    • Infection can induce autoimmune disorders, sometimes transiently (e.g., reactive arthritis). In severe cases, it becomes chronic.
    • Mechanisms linking infection to autoimmunity include cross-presentation/activation by dendritic cells, liberation of protected antigens, failure to resolve inflammation, and molecular mimicry.
    • Several autoimmune diseases exist, including rheumatic fever, multiple sclerosis, Graves' disease, systemic lupus erythematosus, and others.
    • Defects in immune components, such as mutations in regulatory T-helper cells, cytokine responses, or the generation of antigen-specific peptides, can contribute to autoimmune diseases.
    • All immune cells (B, T and APCs), cytokines and complement may exhibit abnormalities leading to inappropriate activation.
    • Epitope spreading, where the immune response expands to additional self-antigens, is a factor that can worsen ongoing autoimmune responses
    • Treatment options for autoimmune diseases are sometimes broad, not specifically targeted. These options include therapies like transplantation, to remove specific antibodies (plasmapheresis), or anti-T-cell therapies (like cyclosporines). NSAIDS can help manage inflammation.
    • Examples of autoimmune diseases include Systemic Lupus Erythematosus, Rheumatoid Arthritis and Multiple Sclerosis.

    Systemic Lupus Erythematosus (SLE)

    • The prototypic systemic autoimmune disease, and 10 times more prevalent in females.
    • Characterized by the production of anti-self antibodies, such as anti-DNA antibodies, against DNA, RBCs, histones, etc. (internal antigens).
    • Damage results from Type II and III hypersensitivity responses and vasculitis.

    Rheumatoid Arthritis

    • Characterized by autoantibodies against joint proteins (rheumatoid factor, an IgM antibody against self-IgG Fc regions)
    • This results in inflammation within the joints and Type III hypersensitivity is a key factor.

    Multiple Sclerosis

    • Symptoms range from numbness to blindness, paralysis and death.
    • Autoreactive T cells destroy the myelin sheath surrounding nerve cells.
    • Has both genetic and environmental components.
    • Animal models exist.

    Antibody-mediated Autoimmune Diseases

    • Antibodies may act by mimicking normal host components, either overstimulating or blocking normal host receptors.
    • Examples include Graves' disease, where antibodies stimulate thyroid hormone overproduction, and myasthenia gravis, where antibodies block acetylcholine receptors—resulting in muscle dysfunction.

    Genetic Factors

    • Genetic susceptibility can increase the chance of developing spontaneous autoimmune diseases. This can be a broad susceptibility (like HLA - B27), or specific individual defects.

    Treatment

    • Treatment options include transplantation, removal of specific antibodies (plasmapheresis) or anti-T cell therapies (like cyclosporine) and NSAIDS.

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    Autoimmunity PDF 2014

    Description

    Explore Chapter 19 on autoimmunity, where we delve into the mechanisms and factors leading to autoimmune diseases. Understand how auto-reactive T cells and B cells contribute to pathologies and the importance of peripheral tolerance. This quiz highlights both the well-understood and theoretical aspects of autoimmunity.

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