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Viva Question and Answers Related to Hypersensitivity Reactions

Here are 50 viva questions and answers related to hypersensitivity reactions:

  1. What is hypersensitivity?
  • Hypersensitivity is an exaggerated or inappropriate immune response to a substance that is normally harmless.
  1. How many types of hypersensitivity reactions are there?
  • There are four types: Type I, Type II, Type III, and Type IV.
  1. Describe Type I hypersensitivity.
  • Type I hypersensitivity involves immediate IgE-mediated reactions, such as allergies.
  1. What is an allergen?
  • An allergen is a substance that triggers an allergic reaction.
  1. Give an example of a Type I hypersensitivity reaction.
  • Allergic rhinitis (hay fever).
  1. How does an allergic reaction start in Type I hypersensitivity?
  • Sensitization occurs when an individual is first exposed to an allergen, leading to the production of IgE antibodies.
  1. Name a key cell involved in Type I hypersensitivity.
  • Mast cells.
  1. What mediators are released in a Type I hypersensitivity reaction?
  • Histamine, leukotrienes, and prostaglandins.
  1. Define Type II hypersensitivity.
  • Type II hypersensitivity involves antibody-mediated reactions against cells or tissues.
  1. Provide an example of Type II hypersensitivity. – Hemolytic transfusion reaction.
  2. Which antibodies are commonly involved in Type II hypersensitivity? – IgG and IgM.
  3. What is autoimmune hemolytic anemia? – It’s a Type II hypersensitivity where the immune system attacks and destroys red blood cells.
  4. Explain Type III hypersensitivity. – Type III hypersensitivity involves immune complex-mediated reactions.
  5. Give an example of a Type III hypersensitivity disease. – Systemic lupus erythematosus (SLE).
  6. What are immune complexes? – Aggregates of antigens and antibodies.
  7. Describe Type IV hypersensitivity. – Type IV hypersensitivity is cell-mediated, involving T cells.
  8. What is delayed-type hypersensitivity (DTH)? – It’s a type of Type IV hypersensitivity characterized by a delayed response, often seen in contact dermatitis. Viva Question and Answers in Lipid Metabolism
  9. Name a disease associated with Type IV hypersensitivity. – Tuberculosis.
  10. Differentiate between immediate and delayed hypersensitivity. – Immediate hypersensitivity occurs rapidly, while delayed hypersensitivity takes time to manifest.
  11. What is anaphylaxis? – Anaphylaxis is a severe, life-threatening allergic reaction involving multiple organ systems.
  12. How is anaphylaxis treated? – Epinephrine is the first-line treatment.
  13. Explain desensitization in allergies. – It’s a process of gradually exposing an individual to an allergen to reduce the allergic response.
  14. What is the role of eosinophils in hypersensitivity? – Eosinophils are involved in the allergic response and defense against parasites.
  15. Can hypersensitivity reactions be inherited? – Some predisposition to allergies can be inherited.
  16. What is the role of the complement system in Type II hypersensitivity? – Complement can be activated, leading to cell lysis.
  17. Describe the Arthus reaction. – It’s a localized Type III hypersensitivity reaction, often seen in response to repeated exposure to an antigen.
  18. How is the diagnosis of hypersensitivity reactions typically made? – Clinical history, physical examination, and sometimes laboratory tests.
  19. What is the role of cytokines in hypersensitivity reactions? – Cytokines regulate and amplify immune responses in hypersensitivity reactions.
  20. Can hypersensitivity reactions be prevented? – In some cases, avoidance of the trigger (allergen) can prevent reactions.
  21. Why do some individuals develop allergies while others do not? – Genetic and environmental factors play a role in the development of allergies. Viva Question and Answers Related to Carbohydrate Metabolism
  22. How is Type I hypersensitivity different from Type IV hypersensitivity? – Type I involves antibodies (IgE), while Type IV is cell-mediated (T cells).
  23. What is the role of the HLA system in hypersensitivity? – The HLA system influences susceptibility to certain hypersensitivity reactions.
  24. Can vaccines cause hypersensitivity reactions? – Yes, but severe reactions are rare. Most vaccine reactions are mild.
  25. Explain the role of IgE in Type I hypersensitivity. – IgE antibodies bind to mast cells, triggering the release of mediators in response to allergen exposure.
  26. What is the primary effector cell in Type II hypersensitivity? – Macrophages.
  27. What is a skin prick test, and how is it used in diagnosing allergies? – It involves introducing small amounts of allergens into the skin to identify specific allergies.
  28. How does corticosteroid therapy work in hypersensitivity reactions? – Corticosteroids have anti-inflammatory effects, suppressing the immune response.
  29. Explain the concept of “hygiene hypothesis” in the context of hypersensitivity. – It suggests that reduced exposure to infections in early childhood may contribute to the development of allergies.
  30. Can hypersensitivity reactions be localized or systemic? – They can be either localized or systemic, depending on the nature of the immune response.
  31. What is the role of the respiratory system in Type I hypersensitivity? – Allergic reactions can lead to respiratory symptoms, such as asthma and rhinitis.  Viva Questions and Answers Related to Bacteriology
  32. Describe the process of immune complex formation in Type III hypersensitivity. – Antigens and antibodies form complexes that deposit in tissues, triggering inflammation.
  33. How does atopy relate to hypersensitivity? – Atopy refers to a genetic predisposition to develop allergic diseases.
  34. What are some common triggers of Type I hypersensitivity? – Pollens, dust mites, pet dander, insect stings, and certain foods.
  35. Can hypersensitivity reactions resolve on their own? – Mild reactions may resolve without intervention, but severe reactions require treatment.
  36. What is the role of basophils in Type I hypersensitivity? – Basophils, like mast cells, release mediators in response to IgE binding.
  37. Explain the role of antibodies in Type II hypersensitivity. – Antibodies bind to antigens on the surface of cells, leading to their destruction.
  38. How does a patch test work in the diagnosis of contact dermatitis? – Small amounts of allergens are applied to the skin to identify substances causing delayed hypersensitivity.
  39. What is the target organ in Type III hypersensitivity? – Various organs can be affected, depending on where immune complexes deposit.
  40. How can Type IV hypersensitivity contribute to chronic inflammation? – Prolonged activation of T cells can lead to chronic inflammation and tissue damage.
  41. Can hypersensitivity reactions be life-long, or do they sometimes resolve with age? – While some allergies may persist, others may diminish or resolve with age. It varies among individuals. Viva Question and Answers Related to Virology


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