Podcast
Questions and Answers
Which type of hypersensitivity is characterized by IgE antibody production and occurs within minutes to hours of antigen exposure?
Which type of hypersensitivity is characterized by IgE antibody production and occurs within minutes to hours of antigen exposure?
What is the primary immune response mechanism involved in type II hypersensitivity?
What is the primary immune response mechanism involved in type II hypersensitivity?
Which of the following is NOT a characteristic of type IV hypersensitivity?
Which of the following is NOT a characteristic of type IV hypersensitivity?
What occurs during the cross-linking of surface-bound IgE molecules?
What occurs during the cross-linking of surface-bound IgE molecules?
Signup and view all the answers
What is the main consequence of prolonged or repeated exposure to antigens in hypersensitivity reactions?
What is the main consequence of prolonged or repeated exposure to antigens in hypersensitivity reactions?
Signup and view all the answers
Which of the following classifications of hypersensitivity reactions primarily involves antigen-antibody reactions?
Which of the following classifications of hypersensitivity reactions primarily involves antigen-antibody reactions?
Signup and view all the answers
Which of the following mediators is released during type I hypersensitivity reactions?
Which of the following mediators is released during type I hypersensitivity reactions?
Signup and view all the answers
Which mechanism of immune response is associated with type III hypersensitivity?
Which mechanism of immune response is associated with type III hypersensitivity?
Signup and view all the answers
What is a primary characteristic of Type III hypersensitivity reactions?
What is a primary characteristic of Type III hypersensitivity reactions?
Signup and view all the answers
Which type of T cells primarily mediate Type IV hypersensitivity?
Which type of T cells primarily mediate Type IV hypersensitivity?
Signup and view all the answers
Which autoimmune condition is NOT mentioned as associated with antibody-mediated reactions?
Which autoimmune condition is NOT mentioned as associated with antibody-mediated reactions?
Signup and view all the answers
What causes damage in Type III hypersensitivity reactions?
What causes damage in Type III hypersensitivity reactions?
Signup and view all the answers
What is a common diagnostic test for contact dermatitis?
What is a common diagnostic test for contact dermatitis?
Signup and view all the answers
In Type IV hypersensitivity, what is the peak time for the tuberculin (Mantoux) reaction after antigen injection?
In Type IV hypersensitivity, what is the peak time for the tuberculin (Mantoux) reaction after antigen injection?
Signup and view all the answers
Which cytokine is NOT typically involved in delayed hypersensitivity?
Which cytokine is NOT typically involved in delayed hypersensitivity?
Signup and view all the answers
In Type IV hypersensitivity, what is the main role of helper T (TH1) cells?
In Type IV hypersensitivity, what is the main role of helper T (TH1) cells?
Signup and view all the answers
Which statement correctly describes Type IV hypersensitivity?
Which statement correctly describes Type IV hypersensitivity?
Signup and view all the answers
What is a relevant diagnostic test for Type III hypersensitivity?
What is a relevant diagnostic test for Type III hypersensitivity?
Signup and view all the answers
What is the primary component found in delayed hypersensitivity lesions?
What is the primary component found in delayed hypersensitivity lesions?
Signup and view all the answers
Which type of immune complex is primarily involved in Type III hypersensitivity reactions?
Which type of immune complex is primarily involved in Type III hypersensitivity reactions?
Signup and view all the answers
What does a total serum IgE test primarily indicate?
What does a total serum IgE test primarily indicate?
Signup and view all the answers
What type of sensitizing events can trigger Type III hypersensitivity?
What type of sensitizing events can trigger Type III hypersensitivity?
Signup and view all the answers
Which type of hypersensitivity is involved in infections like tuberculosis and leprosy?
Which type of hypersensitivity is involved in infections like tuberculosis and leprosy?
Signup and view all the answers
Which method involves the measurement of specific IgE antibodies?
Which method involves the measurement of specific IgE antibodies?
Signup and view all the answers
What is required for antibody-dependent cell-mediated cytotoxicity (ADCC)?
What is required for antibody-dependent cell-mediated cytotoxicity (ADCC)?
Signup and view all the answers
Which components are generated by complement when activated by IgM and IgG antibodies?
Which components are generated by complement when activated by IgM and IgG antibodies?
Signup and view all the answers
What type of hypersensitivity reaction is exemplified by blood group antibodies?
What type of hypersensitivity reaction is exemplified by blood group antibodies?
Signup and view all the answers
Which mechanism leads to hemolytic anemia in the presence of anti-A or anti-B antibodies?
Which mechanism leads to hemolytic anemia in the presence of anti-A or anti-B antibodies?
Signup and view all the answers
What do antibodies that bind to extracellular matrix proteins do?
What do antibodies that bind to extracellular matrix proteins do?
Signup and view all the answers
What is a possible outcome when antibodies bind to cell surface receptors?
What is a possible outcome when antibodies bind to cell surface receptors?
Signup and view all the answers
Which of the following best describes the action of IgG antibodies against erythrocytes?
Which of the following best describes the action of IgG antibodies against erythrocytes?
Signup and view all the answers
Which disease is characterized by a stimulatory effect on receptor signaling due to antibody binding?
Which disease is characterized by a stimulatory effect on receptor signaling due to antibody binding?
Signup and view all the answers
What is the primary advantage of allergen-specific IgE testing over skin testing?
What is the primary advantage of allergen-specific IgE testing over skin testing?
Signup and view all the answers
What is considered the gold standard for testing contact dermatitis?
What is considered the gold standard for testing contact dermatitis?
Signup and view all the answers
Which statement best describes the oral food challenge?
Which statement best describes the oral food challenge?
Signup and view all the answers
What does MELISA test for?
What does MELISA test for?
Signup and view all the answers
What could cause false negatives in patch testing?
What could cause false negatives in patch testing?
Signup and view all the answers
Which of the following substances is not typically associated with allergic reactions?
Which of the following substances is not typically associated with allergic reactions?
Signup and view all the answers
During an oral food challenge, how is the allergen administered?
During an oral food challenge, how is the allergen administered?
Signup and view all the answers
What percentage of the population is particularly affected by nickel allergies?
What percentage of the population is particularly affected by nickel allergies?
Signup and view all the answers
Which of the following is NOT a sign or symptom of penicillin allergy?
Which of the following is NOT a sign or symptom of penicillin allergy?
Signup and view all the answers
What triggers penicillin allergy in the immune system?
What triggers penicillin allergy in the immune system?
Signup and view all the answers
What are the two mechanisms through which drug allergies can occur?
What are the two mechanisms through which drug allergies can occur?
Signup and view all the answers
Which type of insect reaction involves symptoms beyond the immediate area of the bite?
Which type of insect reaction involves symptoms beyond the immediate area of the bite?
Signup and view all the answers
What is a common sign of a large local reaction to an insect sting?
What is a common sign of a large local reaction to an insect sting?
Signup and view all the answers
Which substance is NOT mentioned as a potential cause of contact dermatitis?
Which substance is NOT mentioned as a potential cause of contact dermatitis?
Signup and view all the answers
What type of cells mediate reactions to substances like formaldehyde in contact dermatitis?
What type of cells mediate reactions to substances like formaldehyde in contact dermatitis?
Signup and view all the answers
Which of the following insect bites typically causes itching rather than pain?
Which of the following insect bites typically causes itching rather than pain?
Signup and view all the answers
Study Notes
Hypersensitivity Reactions
- Hypersensitivity refers to undesirable reactions produced by the normal immune system, including allergies and autoimmune conditions.
- These reactions are often over-reactions, potentially causing damage, discomfort, or even death.
- Hypersensitivity reactions require a pre-sensitized immune state in the host.
Teaching Objectives
- Understand the classification of hypersensitivity reactions
- Identify diseases associated with hypersensitivity reactions
- Understand the mechanisms of damage in hypersensitivity reactions
- Learn methods for diagnosing conditions related to hypersensitivity
Types of Hypersensitivity
- Hypersensitivity reactions are originally categorized into immediate and delayed responses.
- Four specific types of hypersensitivity have been identified: Type I, Type II, Type III, and Type IV.
Type I Hypersensitivity
- Also known as immediate hypersensitivity.
- Occurs within minutes to hours after exposure.
- Involves IgE antibodies reacting with mast cells and basophils.
- Triggers lead to release of inflammatory mediators like histamine.
- Examples include allergic rhinitis, asthma, and anaphylaxis.
- Diagnosis: History taking to identify the allergen, Skin tests (intradermal injection of allergens), Measuring total serum IgE levels, and Specific IgE levels to various allergens (RAST)
Type II Hypersensitivity
- Also called cytotoxic hypersensitivity.
- Primarily mediated by antibodies (IgM or IgG) that target cells for destruction.
- Can affect multiple organs and tissues.
- Examples include some autoimmune diseases (e.g., drug-induced hemolytic anemia, granulocytopenia, thrombocytopenia).
- Antibodies interact with cell surface antigens, triggering complement activation, phagocytosis, or NK cell activity.
- Laboratory tests include detection of circulating antibodies targeting tissues, and presence of antibody and complement in the lesion.
Type III Hypersensitivity
- Also known as immune complex-mediated hypersensitivity.
- Involves immune complexes (antigen-antibody complexes), which deposit in tissues.
- Activation of complement and inflammatory responses lead to tissue damage.
- Examples include systemic lupus erythematosus, serum sickness, and some types of glomerulonephritis.
- Diagnosis typically includes visualizing complex deposits in tissues using immunofluorescence microscopy, and measuring immune complex levels in serum.
Type IV Hypersensitivity
- Also known as cell-mediated or delayed hypersensitivity.
- Involves T cells and macrophages, not antibodies.
- Reaction time is typically minutes to days.
- Examples include contact dermatitis (e.g. poison ivy), some autoimmune diseases, and transplant rejection.
- Cell-mediated destruction or activation of macrophages by cytokines results in tissue damage.
- Diagnosis includes skin tests(e.g., Mantoux test), observation of delayed cutaneous reaction.
Clinical Conditions
- Include transfusion reactions, Rh incompatibility, various autoimmune diseases, and graft rejection.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the different types of hypersensitivity reactions in immunology. This quiz covers key characteristics, immune response mechanisms, and associated conditions for types I through IV. Ideal for students and professionals looking to refresh their understanding of hypersensitivity.
