Leprosy: serology and molecular tests: practice question

A Dermatology 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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Dermatology · Leprosy: serology and molecular tests

Sample item

Which antigen is targeted in serological tests for leprosy, with high titres in multibacillary disease?

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

The answer and the reasoning

D. Phenolic glycolipid-1 (PGL-1)

Anti-PGL-1 IgM antibodies are high in lepromatous disease and low in tuberculoid disease, so they have limited sensitivity in paucibacillary cases. PCR for M. leprae-specific sequences such as RLEP assists diagnosis.

Option by option

  • A. Heat shock protein 65 of Legionella

    Legionella protein is unrelated.

  • B. ESAT-6

    ESAT-6 is a tuberculosis antigen used in interferon gamma release assays.

  • C. Lipoarabinomannan of M. tuberculosis

    Lipoarabinomannan assays detect tuberculosis.

  • D. Phenolic glycolipid-1 (PGL-1) (correct)

    Correct. PGL-1 is a species-specific glycolipid.

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 Dermatology question

What is the answer to this Dermatology question?

The best answer is D, Phenolic glycolipid-1 (PGL-1). Anti-PGL-1 IgM antibodies are high in lepromatous disease and low in tuberculoid disease, so they have limited sensitivity in paucibacillary cases.

Why is "Heat shock protein 65 of Legionella" not the answer?

Legionella protein is unrelated.

Why is "ESAT-6" not the answer?

ESAT-6 is a tuberculosis antigen used in interferon gamma release assays.

Why is "Lipoarabinomannan of M. tuberculosis" not the answer?

Lipoarabinomannan assays detect tuberculosis.

What concept does this question test?

It tests Leprosy: serology and molecular tests in Dermatology. PCR for M. leprae-specific sequences such as RLEP assists diagnosis.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Leprosy: serology and molecular tests?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.