Immunology: pemphigus vulgaris autoantigen: practice question

A Microbiology 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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Microbiology · Immunology: pemphigus vulgaris autoantigen

Sample item

A 45-year-old man has painful oral erosions and flaccid blisters on the trunk that rupture easily; pressure on normal skin next to a blister extends it. Biopsy shows suprabasal acantholysis with intercellular IgG deposition. Which antigen is targeted?

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

The answer and the reasoning

D. Desmoglein 3

Pemphigus vulgaris is a type II hypersensitivity in which IgG against desmoglein 3 (and often desmoglein 1) disrupts keratinocyte adhesion, causing suprabasal acantholysis and flaccid blisters with mucosal involvement. Subepidermal blistering diseases target hemidesmosomal proteins such as BP180 and type VII collagen.

Option by option

  • A. Laminin 332 only

    Laminin 332 is the target in mucous membrane pemphigoid, which has subepithelial, not suprabasal, cleavage.

  • B. BP180 (type XVII collagen)

    BP180 is the target in bullous pemphigoid, which produces tense subepidermal blisters.

  • C. Type VII collagen

    Type VII collagen is the target in epidermolysis bullosa acquisita, a subepidermal disease.

  • D. Desmoglein 3 (correct)

    Correct. Anti-desmoglein 3 antibodies cause intraepidermal acantholysis in pemphigus vulgaris.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Desmoglein 3. Pemphigus vulgaris is a type II hypersensitivity in which IgG against desmoglein 3 (and often desmoglein 1) disrupts keratinocyte adhesion, causing suprabasal acantholysis and flaccid blisters with mucosal involvement.

Why is "Laminin 332 only" not the answer?

Laminin 332 is the target in mucous membrane pemphigoid, which has subepithelial, not suprabasal, cleavage.

Why is "BP180 (type XVII collagen)" not the answer?

BP180 is the target in bullous pemphigoid, which produces tense subepidermal blisters.

Why is "Type VII collagen" not the answer?

Type VII collagen is the target in epidermolysis bullosa acquisita, a subepidermal disease.

What concept does this question test?

It tests Immunology: pemphigus vulgaris autoantigen in Microbiology. Subepidermal blistering diseases target hemidesmosomal proteins such as BP180 and type VII collagen.

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 Immunology: pemphigus vulgaris autoantigen?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.