Hypersensitivity and Autoimmunity Quiz
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Questions and Answers

What is the primary characteristic of hypersensitivity reactions?

  • They only occur in older adults.
  • They are regulated by the nervous system.
  • They enhance the body's immune responses.
  • They involve exaggerated and misdirected immune responses. (correct)

In which situation does autoimmunity occur?

  • When the immune system is suppressed.
  • When the immune response is directed at infectious agents.
  • When the immune system fails to recognize self tissues. (correct)
  • When the body is exposed to harmless substances.

What can be a consequence of hypersensitivity reactions?

  • Increased tolerance to allergens.
  • Tissue damage due to immune responses. (correct)
  • Improved immune function.
  • Decreased likelihood of infections.

Which statement best describes the nature of autoimmune diseases?

<p>The specific tissue attacked varies among different diseases. (C)</p> Signup and view all the answers

Which of the following is an example of a hypersensitivity reaction?

<p>Anaphylaxis to bee stings. (A)</p> Signup and view all the answers

What initiates the sensitization phase in Type 1 hypersensitivity reactions?

<p>Production of IgE antibodies (A)</p> Signup and view all the answers

What is the main consequence of subsequent exposures to an allergen in Type 1 hypersensitivity?

<p>Release of chemical mediators (C)</p> Signup and view all the answers

Which symptom is NOT commonly caused by the release of histamine in Type 1 hypersensitivity reactions?

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

Anaphylaxis is characterized by which of the following?

<p>Widespread vasodilation and shock (A)</p> Signup and view all the answers

What is a common treatment for Type 1 hypersensitivity reactions?

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

Which of the following is usually considered the first step in developing a Type 1 hypersensitivity reaction?

<p>IgE production (A)</p> Signup and view all the answers

In the context of mast cell mediators, what role does histamine play?

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

Which condition represents a localized reaction in Type 1 hypersensitivity?

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

What is a key feature of the provocative dose in Type 1 hypersensitivity?

<p>It results in the release of chemical mediators (A)</p> Signup and view all the answers

Which of the following is NOT an effect of antihistamines in treating Type 1 hypersensitivity reactions?

<p>Increasing mast cell activation (B)</p> Signup and view all the answers

Match the types of hypersensitivity reactions with their primary characteristics:

<p>Type 1 = IgE antibodies and mast cells Type 2 = Cytotoxic antibodies Type 3 = Immune complexes Type 4 = T-cell mediated</p> Signup and view all the answers

Match the symptoms of Type 1 hypersensitivity reactions with their descriptions:

<p>Vasodilation = Redness, itching, and rashes Bronchial constriction = Wheezing and difficulty breathing Nerve stimulation = Headaches Gland stimulation = Increased tear and mucus production</p> Signup and view all the answers

Match the phases of Type 1 hypersensitivity with their descriptions:

<p>Sensitizing Dose = First exposure to an allergen Provocative Dose = Subsequent exposure to the allergen Clonal Selection = B cell processes the allergen Chemical Mediator Release = Mast cell activation and symptom onset</p> Signup and view all the answers

Match the components involved in Type 1 hypersensitivity with their roles:

<p>B cells = Produce IgE antibodies T helper cells = Activate B cells Mast cells = Release chemical mediators IL-4 = Stimulates B cell growth</p> Signup and view all the answers

Match the allergic reactions with their common triggers:

<p>Pollen = Causes hay fever Food = Causes food allergies Insect stings = Causes anaphylaxis Dust mites = Causes asthma symptoms</p> Signup and view all the answers

Match the terms with their definitions in the context of Type 1 hypersensitivity:

<p>IgE = Antibody involved in allergies Histamine = Chemical mediator causing allergy symptoms MHC Class II = Presents allergens to T helper cells Clonal expansion = Increase in specific B cells after sensitization</p> Signup and view all the answers

Match the allergic responses with their types:

<p>Local reactions = Localized swelling and redness Systemic reactions = Anaphylactic shock Seasonal allergies = Triggered by pollens Contact dermatitis = Triggered by skin contact with allergens</p> Signup and view all the answers

Match the types of immune responses with their examples:

<p>Type 1 = Hay fever Type 2 = Transfusion reactions Type 3 = Serum sickness Type 4 = Graft rejection</p> Signup and view all the answers

Match each term with the correct associated effect:

<p>Vasodilation = Increase in blood flow Bronchial constriction = Narrowing of airways Nerve stimulation = Pain sensations Gland stimulation = Excessive secretions</p> Signup and view all the answers

Match the localized Type 1 reactions with their descriptions:

<p>Hay fever = Caused by inhaled allergens like dust, mold spores, and pet dander Asthma = Characterized by severe bronchial constriction Eczema = An inflammatory skin response causing pain and itching Food allergies = Symptoms include vomiting, diarrhea, rash, and skin complications</p> Signup and view all the answers

Match the systemic Type 1 reaction with its characteristic:

<p>Anaphylaxis = Life-threatening systemic reaction to an allergen Bronchial constriction = Severe restriction of airflow Systemic vasodilation = Widespread expansion of blood vessels Shock = A critical drop in blood pressure</p> Signup and view all the answers

Match the treatment methods for Type 1 hypersensitivity with their effects:

<p>Avoidance = Easiest method of prevention but not always feasible Corticosteroids = Inhibit B cells and T cells, reducing IgE production Antihistamines = Block histamine receptors to prevent allergic symptoms Epinephrine = Counteracts severe symptoms in cases of anaphylaxis</p> Signup and view all the answers

Match the symptoms of anaphylaxis with their corresponding effects:

<p>Bronchial constriction = Difficulty in breathing Systemic vasodilation = Swelling and flushing of the skin Shock = Severe drop in blood pressure Rapid heartbeat = Increased heart rate due to stress response</p> Signup and view all the answers

Match the examples of allergens with their type of reaction:

<p>Bee stings = Triggers anaphylaxis Antibiotics = Common trigger for systemic reactions Food = Can cause localized eczema or gastrointestinal symptoms Dust mites = Allergen causing hay fever</p> Signup and view all the answers

Match the localized allergic reactions with their triggers:

<p>Hay fever = Inhaled allergens like pollen Eczema = Ingested or inhaled allergens Asthma = Inhalation of allergens Drug allergies = Injected or ingested medications</p> Signup and view all the answers

Match the treatment options with their mechanisms:

<p>Antihistamines = Assists in blocking the action of histamine Corticosteroids = Reduces overall allergic response Avoidance = Prevents exposure to allergens Epinephrine = Rapid relief during anaphylactic shock</p> Signup and view all the answers

Match the symptoms of localized Type 1 reactions with their conditions:

<p>Rash = Food allergies Itching = Eczema Sneezing = Hay fever Shortness of breath = Asthma</p> Signup and view all the answers

Match the types of hypersensitivity reactions with their categories:

<p>Localized reactions = Type 1 reactions Systemic reactions = Type 1 anaphylaxis IgE-mediated reactions = Type 1 hypersensitivity Delayed reactions = Not classified under Type 1</p> Signup and view all the answers

Match the common symptoms of food allergies with their expressions:

<p>Vomiting = Gastrointestinal symptoms Diarrhea = Gastrointestinal distress Rash = Skin response Respiratory issues = Potential for asthma-like symptoms</p> Signup and view all the answers

Which antibodies are primarily involved in Type 2 hypersensitivity reactions?

<p>IgG and IgM (A)</p> Signup and view all the answers

What is a consequence of Type 2 hypersensitivity reactions?

<p>Transfusion reactions (A)</p> Signup and view all the answers

Which condition is associated with hemolytic disease of the newborn due to Type 2 hypersensitivity?

<p>Rh incompatibility (A)</p> Signup and view all the answers

Type 2 hypersensitivity reactions are primarily directed at which of the following?

<p>Foreign blood cells (B)</p> Signup and view all the answers

Which of the following best describes the immune response in Type 2 hypersensitivity?

<p>Humoral response involving antibodies (A)</p> Signup and view all the answers

Which blood type is considered the universal donor and why?

<p>Type O, because it lacks both A and B antigens (D)</p> Signup and view all the answers

What happens during a transfusion reaction when incompatible blood types are mixed?

<p>Antigens from donor blood bind to recipient's pre-formed antibodies (D)</p> Signup and view all the answers

Which statement is true regarding the Rh factor?

<p>Rh incompatibility can lead to hemolytic disease of the newborn (D)</p> Signup and view all the answers

What is the primary consequence of mixing Type A blood with Type B blood during transfusion?

<p>Agglutination of red blood cells (C)</p> Signup and view all the answers

Which blood type contains both anti-A and anti-B antibodies?

<p>Type O (A)</p> Signup and view all the answers

What is the role of RhoGAM in pregnancy?

<p>To prevent Rh negative mothers from producing antibodies against Rh positive fetal blood cells (A)</p> Signup and view all the answers

Which feature correctly describes Type AB blood?

<p>Contains neither anti-A nor anti-B antibodies (B)</p> Signup and view all the answers

What could be a serious consequence of a transfusion reaction?

<p>Systemic shock and kidney failure (C)</p> Signup and view all the answers

How do antibodies in blood function during a transfusion reaction?

<p>They bind to foreign antigens to neutralize them (B)</p> Signup and view all the answers

What characterizes Rh negative individuals?

<p>Lack of the Rh factor antigen on their red blood cells (C)</p> Signup and view all the answers

Match the blood types with their corresponding antigens:

<p>Type A = A antigen Type B = B antigen Type AB = A and B antigens Type O = No antigens</p> Signup and view all the answers

Match the blood types with their corresponding antibodies:

<p>Type A = Anti-B antibodies Type B = Anti-A antibodies Type AB = No antibodies Type O = Anti-A and Anti-B antibodies</p> Signup and view all the answers

Match the blood types with their designated roles in transfusions:

<p>Type A = Can donate to A and AB Type B = Can donate to B and AB Type AB = Universal recipient Type O = Universal donor</p> Signup and view all the answers

Match the transfusion reaction effects with their descriptions:

<p>Agglutination = Clumping of red blood cells Hemolysis = Destruction of red blood cells Complement Activation = Cell lysis and inflammation Systemic Shock = Widespread inflammation and organ damage</p> Signup and view all the answers

Match the Rh factor types with their characteristics:

<p>Rh-positive = Contains the Rh antigen Rh-negative = Lacks the Rh antigen Rh-positive blood prevalence = 85% of humans Rh-negative blood prevalence = 15% of humans</p> Signup and view all the answers

Match the scenarios with their outcomes regarding the Rh factor:

<p>Rh-negative mother = Can develop antibodies if exposed to Rh-positive blood Rh-positive fetus = May cause hemolytic disease in future pregnancies RhoGAM injection = Prevents antibody development against Rh-positive blood Mixing blood at birth = Triggers immune response in mother</p> Signup and view all the answers

Match the blood type with the corresponding risk of transfusion reaction:

<p>Type A = Risks against Type B or O Type B = Risks against Type A or O Type AB = Risks minimal to Type A and B Type O = Risks against all types</p> Signup and view all the answers

Match the types of immune responses with their effects on blood types:

<p>Type A = Causes anti-B response Type B = Causes anti-A response Type AB = No immune response initiated Type O = Causes both anti-A and anti-B responses</p> Signup and view all the answers

Match the possible consequences of mismatched blood transfusions:

<p>Agglutination = Clumping of cells Hemolysis = Cell destruction Kidney Failure = Due to red blood cell debris filtration Death = Possible rapid outcome of transfusion reactions</p> Signup and view all the answers

Study Notes

Hypersensitivity Reactions

  • Hypersensitivity reactions are exaggerated immune responses that can damage self tissues.
  • These reactions occur when the immune system misdirects its response.

Autoimmunity

  • Autoimmunity occurs when the immune system mistakenly attacks the body's own tissues.
  • Each autoimmune disease targets different specific tissues.

Hypersensitivity Reactions

  • Exaggerated immune responses that damage self-tissues
  • Classified into four types based on the mechanism of reaction
  • Type 1 reactions are commonly known as allergies
  • Type 1 reactions are mediated by IgE antibodies

Type 1 Hypersensitivity Reactions

  • Occur with at least two exposures to an allergen
  • Sensitizing dose: First exposure, IgE is produced and binds to mast cells
  • Provocative dose: Subsequent exposures, triggers the release of chemical mediators from mast cells causing symptoms
  • Chemical mediators include histamine

Mast Cell Mediators

  • Histamine and other chemical mediators cause various symptoms:
    • Vasodilation: Leading to skin rashes
    • Bronchial constriction: Leading to wheezing
    • Stimulation of glands: Leading to tear and mucus production

Examples of Type 1 Reactions

  • Localized Reactions:

    • Hay fever (allergic rhinitis): Inhaled allergens like dust, mold, or pollen
    • Asthma: Inhaled or ingested allergens causing severe bronchial constriction
    • Eczema: Inhaled or ingested allergens triggering inflammatory skin reactions
    • Food or drug allergies: Ingested or injected allergens causing vomiting, diarrhea, rash, or other skin complications

  • Systemic Reaction:

    • Anaphylaxis: Systemic reaction to an allergen, causing widespread vasodilation and potentially fatal shock
      • Can be triggered by insect stings, antibiotics, or serum injections

Treatment of Type 1 Hypersensitivity Reactions

  • Avoidance of allergen
  • Corticosteroids: Inhibit B and T cell activity, reducing IgE production
  • Antihistamines: Block histamine receptors, preventing the action of histamine released by mast cells

Hypersensitivity Reactions

  • An exaggerated immune response that results in tissue damage
  • Four types:
    • Type 1: Involve IgE antibodies and mast cells, considered allergies.
    • Type 2: Involve cytotoxic antibodies.
    • Type 3: Involve immune complexes.
    • Type 4: T-cell mediated.

Type 1: IgE Antibodies and Mast Cells

  • Requires at least two exposures to the allergen
    • First exposure (sensitizing dose): Triggers the production of IgE antibodies
      • Allergen binds to B cell receptor
      • B cell presents allergen to T helper cells
      • T helper cells activate the B cell to release IL-4
      • T helper 2 cells release IL-4
      • B cells differentiate into plasma cells that produce IgE antibodies
      • IgE antibodies bind to mast cells
    • Subsequent exposures (provocative dose): Triggers mast cell degranulation
      • Allergen binds to IgE on mast cells
      • Activates mast cells to release chemical mediators (histamine)

Type 1 Symptoms

  • Histamine release causes:
    • Vasodilation: Redness, itching, rashes
    • Bronchial constriction: Wheezing, difficulty breathing, coughing
    • Nerve stimulation: Headaches
    • Gland stimulation: Increased tear and mucus production

Localized Type 1 Reactions

  • Examples:
    • Hay fever (allergic rhinitis)
    • Asthma
    • Eczema
    • Food allergies
    • Drug allergies

Systemic Type 1 Reactions: Anaphylaxis

  • Life-threatening, widespread response
  • Can be triggered by insect stings, antibiotics, and serum injections
  • Characterized by systemic vasodilation, bronchial constriction, and shock

Type 1 Treatment

  • Avoidance: The easiest and most effective way to manage allergies
  • Corticosteroids: Inhibit B cell and T cell activity
  • Antihistamines: Block histamine receptors on target tissues

Type 2 Hypersensitivity Reactions

  • Involve IgG and IgM antibodies.
  • These are antibodies normally produced during humoral immune responses.
  • These reactions are directed at foreign blood cells.
  • This leads to transfusion reactions and Hemolytic Disease of the Newborn.

Blood Types

  • Based on antigens present on red blood cells
  • Type A: Contains A antigen, has anti-B antibodies
  • Type B: Contains B antigen, has anti-A antibodies
  • Type AB: Contains both A and B antigens, has neither anti-A nor anti-B antibodies
  • Type O: Contains neither A nor B antigens, has anti-A and anti-B antibodies
  • Type O blood is the universal donor due to the lack of A and B antigens

Transfusion Reactions

  • Occur when incompatible blood types are mixed, causing a hypersensitivity reaction, leading to:
    • Agglutination: clumping of red blood cells
    • Hemolysis: destruction of red blood cells
    • Complement Activation: cell lysis and inflammation
    • Systemic Shock: due to widespread inflammation and organ damage
    • Kidney Failure: from the filtration of red blood cell debris by the kidneys
    • Death: can occur quickly due to these complications

Rh Factor

  • Another antigen found on some red blood cells
  • Rh-positive blood is present in ~85% of humans, contains Rh antigen
  • Rh-negative blood is present in ~15% of humans, lacks Rh antigen
  • Rh-negative individuals do not have antibodies against Rh unless previously exposed
  • Hemolytic Disease of the Newborn: occurs when an Rh-negative mother carries an Rh-positive fetus:
    • During pregnancy, the mother's immune system is not exposed to Rh-positive fetal blood cells
    • At birth, there's a mixing of maternal and fetal blood, which leads to the mother developing antibodies against Rh-positive blood
    • This can lead to destruction of red blood cells in future pregnancies, causing miscarriage, premature birth, or hemolytic disease of the newborn
    • RhoGAM: injection of anti-Rh antibodies given to Rh-negative mothers during and after pregnancy to prevent the development of antibodies against Rh-positive fetal blood cells

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Test your knowledge on hypersensitivity reactions and autoimmunity. This quiz covers the mechanisms of these immune responses and their effects on the body. Understand how the immune system can misfire and lead to tissue damage.

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