LU2 Hypersensitivity

1. What is the definition of hypersensitivity?
   a) A normal immune response to infection
   b) An exaggerated or inappropriate immune response
   c) A lack of immune response to pathogens
   d) A mild reaction to allergens

2. Which of the following is a characteristic of Type I hypersensitivity?
   a) Mediated by IgG antibodies
   b) Delayed reaction taking 48–72 hours
   c) Involves IgE and mast cell degranulation
   d) Involves immune complex deposition

3. What type of antibody is primarily involved in Type I hypersensitivity?
   a) IgA
   b) IgE
   c) IgG
   d) IgM

4. What cells are primarily responsible for the release of histamine in Type I hypersensitivity?
   a) Neutrophils
   b) Mast cells and basophils
   c) Macrophages
   d) B cells

5. Which of the following conditions is an example of a Type I hypersensitivity reaction?
   a) Myasthenia gravis
   b) Rheumatoid arthritis
   c) Anaphylaxis
   d) Contact dermatitis

6. Which mediators are released during the immediate phase of Type I hypersensitivity?
   a) IL-2 and IL-10
   b) Histamine and leukotrienes
   c) TNF-alpha and IFN-gamma
   d) IgM and complement proteins

7. What is a life-threatening complication of systemic Type I hypersensitivity reactions?
   a) Autoimmune destruction of cells
   b) Anaphylactic shock
   c) Chronic inflammation
   d) Delayed tissue rejection

8. What term is used to describe individuals with a genetic predisposition to Type I hypersensitivity reactions?
   a) Autoimmune
   b) Atopic
   c) Septic
   d) Tolerant

9. Type II hypersensitivity reactions are primarily mediated by:
   a) T cells
   b) IgG and IgM antibodies
   c) IgE and mast cells
   d) Complement proteins alone

10. What is the mechanism of Type II hypersensitivity?
    a) Immune complex deposition
    b) T-cell mediated inflammation
    c) Antibody-mediated destruction of cells
    d) Overproduction of cytokines

11. Which of the following diseases is an example of a Type II hypersensitivity reaction?
    a) Systemic lupus erythematosus
    b) Graves’ disease
    c) Contact dermatitis
    d) Rheumatoid arthritis

12. In Type II hypersensitivity, which process leads to cell destruction?
    a) Opsonization and phagocytosis
    b) T-cell activation
    c) IgE binding to mast cells
    d) Complement-independent lysis

13. What type of hypersensitivity reaction is hemolytic disease of the newborn (HDN)?
    a) Type I
    b) Type II
    c) Type III
    d) Type IV

14. What causes Type III hypersensitivity reactions?
    a) Autoantibodies attacking tissue
    b) Delayed T-cell response
    c) Deposition of immune complexes in tissues
    d) Direct cytotoxic effects of T cells

15. What immune components are involved in Type III hypersensitivity?
    a) T cells only
    b) Antigen-antibody immune complexes and complement
    c) IgE and mast cells
    d) Neutrophils and eosinophils

16. Which condition is associated with Type III hypersensitivity?
    a) Asthma
    b) Myasthenia gravis
    c) Serum sickness
    d) Contact dermatitis

17. What role do immune complexes play in Type III hypersensitivity?
    a) Bind to mast cells and cause degranulation
    b) Activate complement and cause inflammation
    c) Directly kill infected cells
    d) Inhibit T-cell activation

18. Which hypersensitivity reaction is mediated by T cells rather than antibodies?
    a) Type I
    b) Type II
    c) Type III
    d) Type IV

19. Which of the following is an example of Type IV hypersensitivity?
    a) Anaphylaxis
    b) Rheumatoid arthritis
    c) Contact dermatitis
    d) Serum sickness

20. How long does a Type IV hypersensitivity reaction typically take to manifest?
    a) Within minutes
    b) 1–2 hours
    c) 12–48 hours
    d) More than a week

21. What type of T cells mediate Type IV hypersensitivity?
    a) CD4+ T cells and CD8+ T cells
    b) B cells
    c) Plasma cells
    d) Neutrophils

22. Which cytokine is primarily responsible for macrophage activation in Type IV hypersensitivity?
    a) IL-4
    b) IFN-gamma
    c) IL-10
    d) TGF-beta

23. What is the mechanism of tissue damage in Type IV hypersensitivity?
    a) Activation of complement
    b) Cytotoxic T-cell killing and cytokine-mediated inflammation
    c) IgE binding to mast cells
    d) Antibody-dependent cell lysis

24. Which test is commonly used to assess Type IV hypersensitivity?
    a) Skin prick test
    b) Tuberculin test
    c) Coombs test
    d) Western blot

25. Which of the following conditions is NOT mediated by hypersensitivity reactions?
    a) Systemic lupus erythematosus
    b) Contact dermatitis
    c) Myasthenia gravis
    d) Osteoarthritis

26. What is the role of IL-5 in hypersensitivity reactions?
    a) Activates macrophages
    b) Promotes eosinophil proliferation
    c) Stimulates IgG production
    d) Induces neutrophil apoptosis

27. Which drug class is commonly used to treat Type I hypersensitivity reactions?
    a) Beta blockers
    b) Antihistamines
    c) NSAIDs
    d) Antivirals

28. What is the function of leukotrienes in hypersensitivity reactions?
    a) Inhibit mast cell degranulation
    b) Cause smooth muscle contraction and inflammation
    c) Reduce histamine release
    d) Stimulate T-cell production

29. What is the primary difference between Type II and Type III hypersensitivity?
    a) Type II involves IgE, while Type III involves IgM
    b) Type II affects cell surfaces, while Type III involves immune complex deposition
    c) Type III is immediate, while Type II is delayed
    d) Type III reactions are mediated by B cells

30. What type of cells mediate granuloma formation in chronic Type IV hypersensitivity reactions?
    a) B cells
    b) Macrophages and T cells
    c) Neutrophils
    d) Plasma cells

31. What is the main effector cell in Type I hypersensitivity?
    a) Neutrophils
    b) Macrophages
    c) Mast cells
    d) CD8+ T cells

32. What hypersensitivity reaction is involved in transplant rejection?
    a) Type I
    b) Type II
    c) Type III
    d) Type IV

33. Which hypersensitivity type involves pre-formed antibodies?
    a) Type I
    b) Type II
    c) Type III
    d) Type IV

34. Which immunoglobulin class is the most effective in complement activation?
    a) IgA
    b) IgE
    c) IgG
    d) IgM

Answers

1.b, 2.c, 3.b, 4.b, 5.c, 6.b, 7.b, 8.b, 9.b, 10.c, 11.b, 12.a, 13.b, 14.c, 15.b, 16.c, 17.b, 18.d, 19.c, 20.c, 21.a, 22.b, 23.b, 24.b, 25.d, 26.b, 27.b, 28.b, 29.b, 30.b, 31.c, 32.d, 33.b, 34.d