Here are 50 viva questions and answers related to hypersensitivity reactions:
- What is hypersensitivity?
- Hypersensitivity is an exaggerated or inappropriate immune response to a substance that is normally harmless.
- How many types of hypersensitivity reactions are there?
- There are four types: Type I, Type II, Type III, and Type IV.
- Describe Type I hypersensitivity.
- Type I hypersensitivity involves immediate IgE-mediated reactions, such as allergies.
- What is an allergen?
- An allergen is a substance that triggers an allergic reaction.
- Give an example of a Type I hypersensitivity reaction.
- Allergic rhinitis (hay fever).
- 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.
- Name a key cell involved in Type I hypersensitivity.
- Mast cells.
- What mediators are released in a Type I hypersensitivity reaction?
- Histamine, leukotrienes, and prostaglandins.
- Define Type II hypersensitivity.
- Type II hypersensitivity involves antibody-mediated reactions against cells or tissues.
- Provide an example of Type II hypersensitivity. – Hemolytic transfusion reaction.
- Which antibodies are commonly involved in Type II hypersensitivity? – IgG and IgM.
- What is autoimmune hemolytic anemia? – It’s a Type II hypersensitivity where the immune system attacks and destroys red blood cells.
- Explain Type III hypersensitivity. – Type III hypersensitivity involves immune complex-mediated reactions.
- Give an example of a Type III hypersensitivity disease. – Systemic lupus erythematosus (SLE).
- What are immune complexes? – Aggregates of antigens and antibodies.
- Describe Type IV hypersensitivity. – Type IV hypersensitivity is cell-mediated, involving T cells.
- 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
- Name a disease associated with Type IV hypersensitivity. – Tuberculosis.
- Differentiate between immediate and delayed hypersensitivity. – Immediate hypersensitivity occurs rapidly, while delayed hypersensitivity takes time to manifest.
- What is anaphylaxis? – Anaphylaxis is a severe, life-threatening allergic reaction involving multiple organ systems.
- How is anaphylaxis treated? – Epinephrine is the first-line treatment.
- Explain desensitization in allergies. – It’s a process of gradually exposing an individual to an allergen to reduce the allergic response.
- What is the role of eosinophils in hypersensitivity? – Eosinophils are involved in the allergic response and defense against parasites.
- Can hypersensitivity reactions be inherited? – Some predisposition to allergies can be inherited.
- What is the role of the complement system in Type II hypersensitivity? – Complement can be activated, leading to cell lysis.
- Describe the Arthus reaction. – It’s a localized Type III hypersensitivity reaction, often seen in response to repeated exposure to an antigen.
- How is the diagnosis of hypersensitivity reactions typically made? – Clinical history, physical examination, and sometimes laboratory tests.
- What is the role of cytokines in hypersensitivity reactions? – Cytokines regulate and amplify immune responses in hypersensitivity reactions.
- Can hypersensitivity reactions be prevented? – In some cases, avoidance of the trigger (allergen) can prevent reactions.
- 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
- How is Type I hypersensitivity different from Type IV hypersensitivity? – Type I involves antibodies (IgE), while Type IV is cell-mediated (T cells).
- What is the role of the HLA system in hypersensitivity? – The HLA system influences susceptibility to certain hypersensitivity reactions.
- Can vaccines cause hypersensitivity reactions? – Yes, but severe reactions are rare. Most vaccine reactions are mild.
- 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.
- What is the primary effector cell in Type II hypersensitivity? – Macrophages.
- 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.
- How does corticosteroid therapy work in hypersensitivity reactions? – Corticosteroids have anti-inflammatory effects, suppressing the immune response.
- 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.
- Can hypersensitivity reactions be localized or systemic? – They can be either localized or systemic, depending on the nature of the immune response.
- 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
- Describe the process of immune complex formation in Type III hypersensitivity. – Antigens and antibodies form complexes that deposit in tissues, triggering inflammation.
- How does atopy relate to hypersensitivity? – Atopy refers to a genetic predisposition to develop allergic diseases.
- What are some common triggers of Type I hypersensitivity? – Pollens, dust mites, pet dander, insect stings, and certain foods.
- Can hypersensitivity reactions resolve on their own? – Mild reactions may resolve without intervention, but severe reactions require treatment.
- What is the role of basophils in Type I hypersensitivity? – Basophils, like mast cells, release mediators in response to IgE binding.
- Explain the role of antibodies in Type II hypersensitivity. – Antibodies bind to antigens on the surface of cells, leading to their destruction.
- 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.
- What is the target organ in Type III hypersensitivity? – Various organs can be affected, depending on where immune complexes deposit.
- How can Type IV hypersensitivity contribute to chronic inflammation? – Prolonged activation of T cells can lead to chronic inflammation and tissue damage.
- 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
