Q.1 Which type of hypersensitivity reaction is mediated by IgE antibodies?
Type I
Type II
Type III
Type IV
Explanation - Type I hypersensitivity is immediate and mediated by IgE antibodies, leading to allergic reactions like hay fever or asthma.
Correct answer is: Type I
Q.2 Which immune cells are primarily involved in Type I hypersensitivity?
Macrophages
Mast cells and basophils
Cytotoxic T cells
Neutrophils
Explanation - Mast cells and basophils release histamine and other mediators upon IgE crosslinking in Type I hypersensitivity.
Correct answer is: Mast cells and basophils
Q.3 Hemolytic disease of the newborn is an example of which type of hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Hemolytic disease of the newborn occurs due to IgG antibodies against fetal red blood cells, which is a Type II hypersensitivity.
Correct answer is: Type II
Q.4 Which hypersensitivity reaction involves immune complex deposition?
Type I
Type II
Type III
Type IV
Explanation - Type III hypersensitivity occurs when antigen-antibody complexes deposit in tissues, causing inflammation and tissue damage.
Correct answer is: Type III
Q.5 Contact dermatitis is an example of which type of hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Contact dermatitis is a T cell-mediated delayed hypersensitivity reaction, characteristic of Type IV hypersensitivity.
Correct answer is: Type IV
Q.6 Which mediator is primarily responsible for the wheal-and-flare reaction in allergies?
Histamine
Complement
Cytokines
Prostaglandins
Explanation - Histamine released from mast cells is the key mediator causing vasodilation and increased vascular permeability in allergies.
Correct answer is: Histamine
Q.7 Which type of hypersensitivity reaction is known as delayed-type hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Type IV hypersensitivity reactions are delayed, mediated by T lymphocytes, and typically peak 48–72 hours after exposure.
Correct answer is: Type IV
Q.8 Goodpasture’s syndrome is classified under which type of hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Goodpasture’s syndrome results from antibodies directed against basement membrane antigens, fitting Type II hypersensitivity.
Correct answer is: Type II
Q.9 Arthus reaction is an example of which hypersensitivity type?
Type I
Type II
Type III
Type IV
Explanation - Arthus reaction occurs due to localized immune complex deposition, a feature of Type III hypersensitivity.
Correct answer is: Type III
Q.10 Which hypersensitivity type is primarily cell-mediated rather than antibody-mediated?
Type I
Type II
Type III
Type IV
Explanation - Type IV hypersensitivity is mediated by T lymphocytes instead of antibodies, making it a cell-mediated response.
Correct answer is: Type IV
Q.11 Which hypersensitivity reaction is responsible for acute anaphylaxis?
Type I
Type II
Type III
Type IV
Explanation - Anaphylaxis is a systemic IgE-mediated Type I hypersensitivity reaction characterized by rapid onset and potential fatality.
Correct answer is: Type I
Q.12 The tuberculin skin test is an example of which hypersensitivity type?
Type I
Type II
Type III
Type IV
Explanation - The tuberculin test involves T-cell mediated delayed hypersensitivity reaction, characteristic of Type IV.
Correct answer is: Type IV
Q.13 Which type of hypersensitivity is mediated by complement activation following antibody binding to cells?
Type I
Type II
Type III
Type IV
Explanation - Type II hypersensitivity involves antibody binding to cell-surface antigens, leading to complement-mediated cytotoxicity.
Correct answer is: Type II
Q.14 Farmer’s lung disease is an example of which hypersensitivity reaction?
Type I
Type II
Type III
Type IV
Explanation - Farmer’s lung occurs due to inhalation of organic dust leading to immune complex deposition in lungs (Type III hypersensitivity).
Correct answer is: Type III
Q.15 Which immunoglobulin is mainly involved in Type I hypersensitivity?
IgA
IgE
IgG
IgM
Explanation - IgE binds to Fc receptors on mast cells and basophils, mediating Type I allergic responses.
Correct answer is: IgE
Q.16 In systemic lupus erythematosus, the tissue damage is mainly due to which hypersensitivity type?
Type I
Type II
Type III
Type IV
Explanation - In SLE, immune complexes deposit in tissues, leading to inflammation and organ damage, a hallmark of Type III hypersensitivity.
Correct answer is: Type III
Q.17 Which cytokine is crucial for activating macrophages in Type IV hypersensitivity?
IL-4
IL-10
IFN-γ
TNF-α
Explanation - IFN-γ secreted by Th1 cells activates macrophages during delayed-type (Type IV) hypersensitivity reactions.
Correct answer is: IFN-γ
Q.18 Graves’ disease is classified under which type of hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Graves’ disease results from antibodies stimulating TSH receptors, fitting under Type II hypersensitivity.
Correct answer is: Type II
Q.19 Which hypersensitivity reaction does poison ivy induce?
Type I
Type II
Type III
Type IV
Explanation - Poison ivy exposure leads to a T-cell mediated delayed hypersensitivity reaction, characteristic of Type IV.
Correct answer is: Type IV
Q.20 Serum sickness is an example of which hypersensitivity type?
Type I
Type II
Type III
Type IV
Explanation - Serum sickness is caused by circulating immune complexes depositing in tissues, characteristic of Type III hypersensitivity.
Correct answer is: Type III
Q.21 Which hypersensitivity type is most likely to involve eosinophils in chronic stages?
Type I
Type II
Type III
Type IV
Explanation - Eosinophils are heavily involved in chronic allergic inflammation, making them central in prolonged Type I hypersensitivity.
Correct answer is: Type I
Q.22 Which laboratory test is used to detect Type I hypersensitivity?
Patch test
Skin prick test
Coombs test
ANA test
Explanation - The skin prick test detects immediate IgE-mediated allergic responses by introducing small amounts of allergen into the skin.
Correct answer is: Skin prick test
Q.23 Which type of hypersensitivity involves sensitized Th1 cells releasing cytokines?
Type I
Type II
Type III
Type IV
Explanation - In Type IV hypersensitivity, Th1 cells release cytokines that activate macrophages and recruit immune cells.
Correct answer is: Type IV
Q.24 Which hypersensitivity is primarily responsible for blood transfusion reactions?
Type I
Type II
Type III
Type IV
Explanation - Blood transfusion reactions occur due to antibody-mediated destruction of red blood cells, characteristic of Type II hypersensitivity.
Correct answer is: Type II
Q.25 Which mediator is most responsible for bronchoconstriction in asthma?
Histamine
Leukotrienes
Cytokines
Prostaglandins
Explanation - Leukotrienes are potent mediators released in asthma that cause prolonged bronchoconstriction and airway inflammation.
Correct answer is: Leukotrienes