Hypersensitivity: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · Hypersensitivity

Sample item

Which mechanism underlies immediate anaphylaxis after exposure to a previously sensitizing allergen?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. IgE-mediated mast-cell degranulation

Type I hypersensitivity occurs when allergen cross-links IgE bound to mast cells or basophils, rapidly releasing mediators that can cause urticaria, bronchospasm, hypotension, and angioedema.

Option by option

  • A. Immune-complex deposition only

    Immune-complex deposition is the basis of type III hypersensitivity.

  • B. Direct bacterial invasion

    Bacterial invasion is not the immunologic mechanism of anaphylaxis.

  • C. IgE-mediated mast-cell degranulation (correct)

    Correct: IgE-triggered mast-cell activation causes immediate anaphylaxis.

  • D. Cytotoxic T-cell killing only

    Cytotoxic T-cell injury is a type IV delayed mechanism.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, IgE-mediated mast-cell degranulation. Type I hypersensitivity occurs when allergen cross-links IgE bound to mast cells or basophils, rapidly releasing mediators that can cause urticaria, bronchospasm, hypotension, and angioedema.

Why is "Immune-complex deposition only" not the answer?

Immune-complex deposition is the basis of type III hypersensitivity.

Why is "Direct bacterial invasion" not the answer?

Bacterial invasion is not the immunologic mechanism of anaphylaxis.

Why is "Cytotoxic T-cell killing only" not the answer?

Cytotoxic T-cell injury is a type IV delayed mechanism.

What concept does this question test?

It tests Hypersensitivity in Pathology. The correct option holds because: Correct: IgE-triggered mast-cell activation causes immediate anaphylaxis.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Hypersensitivity?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.