Question

Match the hypersensitivity type with its example. 

• A. A-3, B-1, C-2, D-4
• B. A-1, B-3, C-4, D-2
• C. A-3, B-2, C-1, D-4
• D. A-4, B-1, C-2, D-3

Hint:

Remember the acronym \textbf{ACID} for hypersensitivity types: \textbf{A}llergic (Type I), \textbf{C}ytotoxic (Type II), \textbf{I}mmune complex (Type III), \textbf{D}elayed (Type IV).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The Gell and Coombs classification system categorizes hypersensitivity reactions into four distinct types based on their underlying immune mechanisms.

Step 2: Detailed Explanation:
Let's correctly pair each type with its classic clinical example.
- Type I Hypersensitivity (A): This is an immediate, IgE-mediated reaction against an allergen.
Common examples include typical allergies (like hay fever or asthma).
Thus, A matches with 3.
- Type II Hypersensitivity (B): This is an antibody-mediated (IgG or IgM) cytotoxic reaction targeting cell surface antigens.
In Myasthenia gravis, antibodies inappropriately attack acetylcholine receptors at the neuromuscular junction.
Thus, B matches with 1.
- Type III Hypersensitivity (C): This is an immune complex-mediated reaction where antigen-antibody complexes deposit in tissues, causing inflammation.
Serum sickness is a classic example of a systemic Type III reaction.
Thus, C matches with 2.
- Type IV Hypersensitivity (D): This is a cell-mediated (delayed-type) reaction involving T cells and macrophages.
Contact dermatitis (e.g., from poison ivy exposure) is a classic example that takes 48-72 hours to develop.
Thus, D matches with 4.

Step 3: Final Answer:
Matching these gives the sequence: A-3, B-1, C-2, D-4.
This corresponds perfectly to option (A).