Autoimmunity
50 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the definition of autoimmunity?

A misdirected immune response that occurs when the immune system attacks the body itself.

What is the mechanism for preventing autoimmunity?

  • Activated by self-antigens
  • Central tolerance (correct)
  • Induced in mature lymphocytes
  • Peripheral tolerance (correct)

    • Molecular mimicry involves a foreign antigen cross-reacting with self-antigens in an autoimmune disease.

    True

    Autoimmune conditions are classified similarly to hypersensitivity reactions, except there is no ____ hypersensitivity.

    <p>type I</p> Signup and view all the answers

    Match the following autoimmune conditions with their corresponding immune response type:

    <p>Autoimmune haemolytic anaemia = Antibody-mediated (Type II) Systemic lupus erythematosus (SLE) = Immune-complex mediated (Type III) Rheumatoid arthritis = Cell-mediated (Type IV)</p> Signup and view all the answers

    What is tolerance in the context of autoimmunity?

    <p>Mechanism for preventing autoimmunity by deleting self-reactive T- and B-cells.</p> Signup and view all the answers

    What is the definition of autoimmunity?

    <p>A misdirected immune response attacking the body</p> Signup and view all the answers

    ______ initiates an immune response that can lead to autoimmune disease.

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

    Autoimmune conditions are classified similarly to hypersensitivity reactions.

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

    Match the type of hypersensitivity reaction with the autoimmune condition:

    <p>Antibody-mediated (Type II) = Autoimmune haemolytic anaemia Immune-complex mediated (Type III) = Systemic lupus erythematosus (SLE) Cell-mediated (Type IV) = Rheumatoid arthritis</p> Signup and view all the answers

    What is the most common ocular manifestation in patients with Rheumatoid Arthritis (RA)?

    <p>Keratoconjunctivitis sicca</p> Signup and view all the answers

    What is the primary effect of Graves' disease on the eyes?

    <p>Inflammation and congestion of periocular and orbital soft tissue</p> Signup and view all the answers

    Which of the following is a common ocular manifestation of Systemic Lupus Erythematosus (SLE)?

    <p>All of the above</p> Signup and view all the answers

    What is the approximate percentage of patients with Rheumatoid Arthritis (RA) who will have ocular manifestations?

    <p>25%</p> Signup and view all the answers

    Which demographic is more commonly affected by Graves' disease?

    <p>Women of childbearing age</p> Signup and view all the answers

    What is the type of hypersensitivity reaction involved in Rheumatoid Arthritis (RA)?

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

    Which of the following is a complication of Graves' disease?

    <p>All of the above</p> Signup and view all the answers

    What is the primary ocular manifestation of Sjögren's syndrome?

    <p>Keratoconjunctivitis sicca</p> Signup and view all the answers

    What is the percentage of scleritis cases caused by Rheumatoid Arthritis (RA)?

    <p>18-33%</p> Signup and view all the answers

    What is the key difference in symptoms between scleritis and episcleritis?

    <p>Scleritis has more severe and evident pain</p> Signup and view all the answers

    What is the characteristic of blood vessels in scleritis?

    <p>They remain dilated</p> Signup and view all the answers

    What is the primary cause of elevated blood glucose levels in Diabetes Mellitus (Type 1)?

    <p>Destruction of insulin-producing cells in the pancreas</p> Signup and view all the answers

    What is the primary ocular complication of Diabetes Mellitus (Type 1)?

    <p>Diabetic retinopathy</p> Signup and view all the answers

    What is the primary characteristic of Sjögren's Syndrome?

    <p>Dry eyes and dry mouth</p> Signup and view all the answers

    What is the primary mechanism for preventing complications of Diabetes Mellitus (Type 1)?

    <p>Regular eye exams and control of blood sugar levels</p> Signup and view all the answers

    Which autoimmune condition is associated with Graves' Disease?

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

    What is the primary mechanism of antibody-mediated (Type II) hypersensitivity reaction in autoimmune haemolytic anaemia?

    <p>Opsonisation and phagocytosis by macrophages in spleen</p> Signup and view all the answers

    In systemic lupus erythematosus (SLE), what is the primary mechanism of immune complex-mediated (Type III) hypersensitivity reaction?

    <p>Immune complex deposition in tissues leading to dysfunction</p> Signup and view all the answers

    What is the primary mechanism of cell-mediated (Type IV) hypersensitivity reaction in rheumatoid arthritis?

    <p>Autoimmune T-cell responses leading to inflammation and destruction</p> Signup and view all the answers

    What is the characteristic feature of Mooren's ulcer?

    <p>Painful, relentless, chronic ulcerative keratitis</p> Signup and view all the answers

    What is the possible etiology of Mooren's ulcer?

    <p>Autoimmune reactions to self-antigens</p> Signup and view all the answers

    In type I diabetes mellitus, what is the primary mechanism of cell-mediated (Type IV) hypersensitivity reaction?

    <p>Autoimmune T-cell responses leading to destruction of insulin producing cells</p> Signup and view all the answers

    What is the primary mechanism of immune-complex mediated (Type III) hypersensitivity reaction in ocular autoimmune diseases?

    <p>Immune complex deposition in tissues leading to dysfunction</p> Signup and view all the answers

    What is the common feature of autoimmune conditions classified under hypersensitivity reactions?

    <p>No Type I hypersensitivity reaction</p> Signup and view all the answers

    Which of the following mechanisms is responsible for deleting self-reactive lymphocytes in the early stages of lymphocyte development?

    <p>Central tolerance</p> Signup and view all the answers

    What is the role of T-regulatory cells (Tregs) in the immune system?

    <p>To suppress autoreactions</p> Signup and view all the answers

    Which of the following is NOT a factor that contributes to abnormal regulation of the immune response?

    <p>Antigen presentation</p> Signup and view all the answers

    What is the primary consequence of molecular mimicry?

    <p>Autoimmune disease</p> Signup and view all the answers

    Which of the following autoimmune conditions is NOT characterized by ocular manifestations?

    <p>Diabetic Retinopathy</p> Signup and view all the answers

    What is the primary role of the immune system in autoimmune diseases?

    <p>To attack self-antigens</p> Signup and view all the answers

    Which of the following autoimmune conditions is characterized by dry eye?

    <p>Sjögren's Syndrome</p> Signup and view all the answers

    What is the primary characteristic of hypersensitivity reactions in autoimmune diseases?

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

    What is a possible association with sympathetic ophthalmia?

    <p>HLA-A11</p> Signup and view all the answers

    What is the typical time frame for the presentation of sympathetic ophthalmia?

    <p>Between 2 weeks and 3 months</p> Signup and view all the answers

    What is a characteristic finding in keratoconjunctivitis sicca?

    <p>Punctate erosive keratopathy</p> Signup and view all the answers

    What is the primary mechanism of sympathetic ophthalmia?

    <p>Allergic theory</p> Signup and view all the answers

    What type of injury is commonly associated with sympathetic ophthalmia?

    <p>Penetrating injury</p> Signup and view all the answers

    What is a possible complication of sympathetic ophthalmia?

    <p>Subretinal neovascularization</p> Signup and view all the answers

    What is a symptom of keratoconjunctivitis sicca?

    <p>Worsening symptoms in the latter part of the day</p> Signup and view all the answers

    What is a predisposing factor for sympathetic ophthalmia?

    <p>Penetrating injury</p> Signup and view all the answers

    Study Notes

    Autoimmunity

    • Autoimmunity is a misdirected immune response that occurs when the immune system attacks the body itself.
    • It is a hypersensitivity reaction triggered by self-antigens.
    • Molecular mimicry is a mechanism that can lead to autoimmunity, where a foreign antigen initiates an immune response, and a T- or B-cell component cross-recognizes self-antigens, leading to an autoimmune disease.

    Tolerance

    • The body has mechanisms to remove self-reactive T- and B-cells to prevent autoimmunity.
    • Central tolerance is the mechanism that deletes self-reacting lymphocytes in the early stages of lymphocyte development (in thymus or bone marrow).
    • Peripheral tolerance is a "safety net" that removes self-reactive lymphocytes that have escaped central tolerance, induced in mature lymphocytes, and involves T-regulatory cells (Tregs) that suppress autoreactions.

    Classification of Autoimmune Conditions

    • Autoimmune conditions are classified similarly to hypersensitivity reactions, with the exception of type I hypersensitivity.
    • There are three types of autoimmune conditions:
      • Antibody-mediated (Type II) hypersensitivity reactions
      • Immune-complex mediated (Type III) hypersensitivity reactions
      • Cell-mediated (Type IV) hypersensitivity reactions

    Antibody-Mediated (Type II) Hypersensitivity Reactions

    • Antibody-mediated reactions occur when an antibody reacts to self-antigens, binds to tissue/cells, and results in opsonisation and complement activation.
    • Example: autoimmune haemolytic anaemia.

    Immune-Complex Mediated (Type III) Hypersensitivity Reactions

    • Immune-complex mediated reactions occur when immune complexes are not cleared rapidly, leading to inflammation and tissue damage.
    • Example: systemic lupus erythematosus (SLE).

    Cell-Mediated (Type IV) Hypersensitivity Reactions

    • Cell-mediated reactions occur when autoimmune T-cell responses lead to inflammation and tissue damage.
    • Examples: rheumatoid arthritis, type I diabetes mellitus.

    Ocular Autoimmune Diseases

    • Mooren's ulcer: a rare disorder characterized by a painful, relentless, chronic ulcerative keratitis.
    • Sympathetic ophthalmia: a bilateral granulomatous uveitis that occurs after a penetrating injury to one eye, potentially blinding.

    Systemic Autoimmune Diseases

    • Keratoconjunctivitis sicca: a dry eye syndrome characterized by dryness, corneal examination may reveal punctate erosive keratopathy or filaments.
    • Scleritis: inflammation of the sclera, characterized by pain, tenderness, and decreased vision.
    • Rheumatoid arthritis: a chronic inflammatory disorder that affects the joints, skin, eyes, lungs, heart, and blood vessels.
    • Sjögren's syndrome: an autoimmune condition characterized by dry eyes and a dry mouth, affecting the mucous membranes and moisture-secreting glands of eyes and mouth.
    • Graves' disease: an autoimmune condition resulting in hyperthyroidism, characterized by inflammation and congestion of periocular and orbital soft tissue.
    • Systemic lupus erythematosus (SLE): a chronic inflammatory disease that can affect multiple organ systems, including the eyes.

    Autoimmunity

    • Autoimmunity is a misdirected immune response that occurs when the immune system attacks the body itself.
    • It is a hypersensitivity reaction triggered by self-antigens.
    • Molecular mimicry is a mechanism that can lead to autoimmunity, where a foreign antigen initiates an immune response, and a T- or B-cell component cross-recognizes self-antigens, leading to an autoimmune disease.

    Tolerance

    • The body has mechanisms to remove self-reactive T- and B-cells to prevent autoimmunity.
    • Central tolerance is the mechanism that deletes self-reacting lymphocytes in the early stages of lymphocyte development (in thymus or bone marrow).
    • Peripheral tolerance is a "safety net" that removes self-reactive lymphocytes that have escaped central tolerance, induced in mature lymphocytes, and involves T-regulatory cells (Tregs) that suppress autoreactions.

    Classification of Autoimmune Conditions

    • Autoimmune conditions are classified similarly to hypersensitivity reactions, with the exception of type I hypersensitivity.
    • There are three types of autoimmune conditions:
      • Antibody-mediated (Type II) hypersensitivity reactions
      • Immune-complex mediated (Type III) hypersensitivity reactions
      • Cell-mediated (Type IV) hypersensitivity reactions

    Antibody-Mediated (Type II) Hypersensitivity Reactions

    • Antibody-mediated reactions occur when an antibody reacts to self-antigens, binds to tissue/cells, and results in opsonisation and complement activation.
    • Example: autoimmune haemolytic anaemia.

    Immune-Complex Mediated (Type III) Hypersensitivity Reactions

    • Immune-complex mediated reactions occur when immune complexes are not cleared rapidly, leading to inflammation and tissue damage.
    • Example: systemic lupus erythematosus (SLE).

    Cell-Mediated (Type IV) Hypersensitivity Reactions

    • Cell-mediated reactions occur when autoimmune T-cell responses lead to inflammation and tissue damage.
    • Examples: rheumatoid arthritis, type I diabetes mellitus.

    Ocular Autoimmune Diseases

    • Mooren's ulcer: a rare disorder characterized by a painful, relentless, chronic ulcerative keratitis.
    • Sympathetic ophthalmia: a bilateral granulomatous uveitis that occurs after a penetrating injury to one eye, potentially blinding.

    Systemic Autoimmune Diseases

    • Keratoconjunctivitis sicca: a dry eye syndrome characterized by dryness, corneal examination may reveal punctate erosive keratopathy or filaments.
    • Scleritis: inflammation of the sclera, characterized by pain, tenderness, and decreased vision.
    • Rheumatoid arthritis: a chronic inflammatory disorder that affects the joints, skin, eyes, lungs, heart, and blood vessels.
    • Sjögren's syndrome: an autoimmune condition characterized by dry eyes and a dry mouth, affecting the mucous membranes and moisture-secreting glands of eyes and mouth.
    • Graves' disease: an autoimmune condition resulting in hyperthyroidism, characterized by inflammation and congestion of periocular and orbital soft tissue.
    • Systemic lupus erythematosus (SLE): a chronic inflammatory disease that can affect multiple organ systems, including the eyes.

    Ocular Manifestations of Autoimmune Diseases

    • Keratoconjunctivitis sicca is a common ocular manifestation of autoimmune diseases, particularly in women over 40 years old.
    • Treatment of keratoconjunctivitis sicca is symptomatic.

    Rheumatoid Arthritis (RA)

    • RA is a chronic inflammatory disorder primarily affecting the joints, but also affecting the skin, eyes, lungs, heart, and blood vessels.
    • It is a cell-mediated (type IV) hypersensitivity reaction.
    • Approximately 25% of patients with RA will have ocular manifestations, including:
      • Keratoconjunctivitis sicca (most common, up to 25% of patients)
      • Scleritis/episcleritis (4-10% of patients with RA)
      • Keratitis
      • Peripheral corneal ulceration

    Graves' Disease

    • Graves' disease is an autoimmune condition resulting in hyperthyroidism (overproduction of thyroid hormones).
    • Inflammation and congestion of periocular and orbital soft tissue occur in Graves' disease.
    • Ocular manifestations of Graves' disease include:
      • Graves' ophthalmopathy
      • Exposure keratopathy
      • Diplopia
      • Compressive optic neuropathy

    Systemic Lupus Erythematosus (SLE)

    • SLE is an autoimmune disease that occurs more frequently in women, particularly those of childbearing age.
    • Ocular disease occurs in 20% of SLE patients, with external ocular manifestations including:
      • Keratoconjunctivitis sicca
      • Conjunctivitis
      • Uveitis
      • Episcleritis and scleritis
      • Keratitis
      • Discoid lupus rash over the eyelids
    • Intraocular manifestations of SLE include:
      • Microinfarction
      • Hemorrhage
      • Vasculitis in various locations
      • Optic neuritis/optic neuropathy

    Sympathetic Ophthalmia

    • Sympathetic ophthalmia is a rare, bilateral, granulomatous uveitis that occurs after a penetrating injury to one eye.
    • It is a potentially blinding disease that involves both eyes.
    • More frequent in men, with a possible association with HLA-A11.
    • Predisposing factors include:
      • Penetrating injury (almost always occurs after a penetrating injury)
      • Ciliary region wounds = dangerous zone
    • Pathogenesis involves multiple theories, including the "allergic theory" and molecular mimicry.

    Keratoconjunctivitis Sicca

    • Keratoconjunctivitis sicca is a dry eye syndrome.
    • Symptoms include:
      • More prominent during the latter part of the day due to the evaporation of the tear film
      • Corneal examination (slit lamp) may reveal punctate erosive keratopathy or filaments

    Scleritis and Episcleritis

    • Scleritis and episcleritis are distinguished based on anatomy and appearance.
    • Symptoms may be similar, with scleritis having more severe pain and tenderness to palpation of the globe.
    • Scleritis is more common in patients with RA, and patients with scleritis and RA have a worse prognosis.

    Diabetes Mellitus (Type 1)

    • Diabetes mellitus is an autoimmune condition where the insulin-producing cells in the pancreas are destroyed.
    • It leads to elevated blood glucose levels and damages the blood vessels in most organ systems, including the eye.
    • Ocular complications include:
      • Diabetic retinopathy
      • Cataract formation
      • Glaucoma
    • Prevention of complications involves controlling blood sugar levels and regular eye exams.

    Sjögren's Syndrome

    • Sjögren's syndrome is an autoimmune condition characterized by dry eyes and a dry mouth.
    • It results in decreased production of tears and saliva due to molecular mimicry.

    Classification of Autoimmune Conditions

    • Autoimmune conditions are classified similarly to hypersensitivity reactions, with the exception of type I hypersensitivity.
    • Types of autoimmune conditions include:
      • Antibody-mediated (type II) hypersensitivity reactions
      • Immune-complex mediated (type III) hypersensitivity reactions
      • Cell-mediated (type IV) hypersensitivity reactions

    Mooren's Ulcer

    • Mooren's ulcer is a rare disorder characterized by a painful, relentless, chronic ulcerative keratitis.
    • It typically occurs in healthy, adult men, with no evidence of systemic disease.
    • Etiology is unsure, but possible autoimmune reactions include exposure to infectious agents.

    Autoimmunity

    • Tolerance is the mechanism for preventing autoimmunity, where self-reactive T- and B-cells are removed.
    • Autoimmunity occurs when the immune system goes awry and attacks the body itself, triggering hypersensitivity reactions to self-antigens.
    • Molecular mimicry is a process where foreign antigens initiate an immune response, leading to cross-reactive immune responses against self-antigens.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Autoimmunity Session 7 PDF

    Description

    This quiz covers the basics of autoimmunity, including definitions, pathogenesis, and classification. It also explores ocular and systemic autoimmune conditions.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser