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 (D)</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 (B)</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 (B)</p> Signup and view all the answers

What primarily causes damage in Systemic Lupus Erythematosis?

<p>Type III hypersensitivity responses (C)</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 (B)</p> Signup and view all the answers

Which statement accurately describes Rheumatoid Arthritis?

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

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

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

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

<p>To suppress inappropriate immune responses (A)</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 (D)</p> Signup and view all the answers

Which factors contribute to the pathogenesis of Multiple Sclerosis?

<p>Environmental and genetic components (C)</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 (A)</p> Signup and view all the answers

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

<p>Anti-DNA antibodies (B)</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 (A)</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. (C)</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. (A)</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. (C)</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 (D)</p> Signup and view all the answers

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

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

What is a common approach for treating autoimmune diseases?

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

Which treatment involves the removal of specific antibodies?

<p>Plasmapheresis (C)</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 (A)</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. (D)</p> Signup and view all the answers

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

<p>Antibiotics (D)</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. (B)</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 (C)</p> Signup and view all the answers

Flashcards

Autoimmune Disease

A condition where the immune system mistakenly attacks the body's own tissues and organs.

Central Tolerance

The process of eliminating self-reactive immune cells during their development in the thymus and bone marrow.

Peripheral Tolerance

The mechanisms that prevent self-reactive immune cells from causing harm in the body's periphery.

Regulatory T Cells

Immune cells that suppress the activity of other immune cells, preventing autoimmune reactions.

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Cross-Presentation

A process where antigen-presenting cells (APCs) display antigens from infected cells to T cells, triggering an immune response.

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Molecular Mimicry

When a pathogen's antigen resembles a self-antigen, causing the immune system to attack both.

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Infection-Induced Autoimmunity

Autoimmunity triggered by an infection, often due to cross-presentation, molecular mimicry, or persistent inflammation.

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Defects in Immune Components

Mutations or abnormalities in immune cells, such as T cells, B cells, or cytokines, leading to autoimmune reactions.

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Escape of Autoreactive Cells

When self-reactive immune cells evade the central tolerance mechanisms and enter the periphery.

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Failure of Peripheral Tolerance

When the peripheral tolerance mechanisms fail to prevent self-reactive immune cells from attacking the body.

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Autoantibody Mimicry

When antibodies mistakenly target normal host components, mimicking their function and either over-stimulating or blocking them.

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Graves' Disease

An autoimmune disease where autoantibodies bind to the thyroid-stimulating hormone receptor, causing overproduction of thyroid hormones.

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Myasthenia Gravis

An autoimmune disease where autoantibodies block acetylcholine receptors on muscles, leading to muscle weakness and fatigue.

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Genetic Predisposition in Autoimmunity

While anyone can develop autoimmune diseases, some individuals are more genetically susceptible due to factors like specific gene variants or broader HLA haplotypes.

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HLA-B27 Susceptibility

A specific example of broad genetic susceptibility to autoimmune diseases, where individuals with the HLA-B27 gene have increased risk for conditions like ankylosing spondylitis.

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Autoimmune Treatment: Downregulation

Current treatments for autoimmune diseases often focus on downregulating the immune system to reduce its activity, since they lack precise targeting of the specific autoreactive immune components.

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Plasmapheresis

A treatment for autoimmune diseases that involves removing the specific autoreactive antibodies from the blood plasma.

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Anti-T Cell Therapies

Treatments for autoimmune diseases that target T lymphocytes, crucial players in the immune response, to reduce their activity.

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NSAIDs in Autoimmune Treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to control inflammation, a common symptom associated with many autoimmune diseases.

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Understanding Treatment Mechanisms

It's crucial to understand the mechanisms of action of various autoimmune treatments in relation to the immune response, enabling better interpretation and application.

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Epitope Spreading

The immune response expands to target new epitopes, which can include self-antigens.

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Systemic Lupus Erythematosus (SLE)

A systemic autoimmune disease characterized by the production of autoantibodies against various self-antigens, including DNA, RBCs, and histones.

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Rheumatoid Arthritis (RA)

A chronic autoimmune disease characterized by inflammation of the joints, often accompanied by the production of anti-joint protein autoantibodies and rheumatoid factor.

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Multiple Sclerosis (MS)

A chronic autoimmune disease affecting the central nervous system, characterized by the destruction of the myelin sheath surrounding nerve cells.

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Type II Hypersensitivity

Immune reaction involving antibodies directed against cell surface antigens, leading to cell destruction.

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Type III Hypersensitivity

Immune reaction involving the formation of immune complexes (antigen-antibody) that deposit in tissues, causing inflammation.

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Vasculitis

Inflammation of blood vessels, often caused by immune complexes or autoreactive T cells.

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Mechanisms of Autoimmune Disease

The processes by which the immune system targets self-antigens, leading to tissue damage and disease.

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Clinical Importance of Autoimmune Disease

The impact of autoimmune diseases on patient health and quality of life.

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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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