Blood and immunity: central tolerance and AIRE: practice question

A Physiology 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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Physiology · Blood and immunity: central tolerance and AIRE

Sample item

A boy has chronic mucocutaneous candidiasis, hypoparathyroidism and autoimmune adrenal failure from a mutation in a transcription factor expressed in thymic medullary epithelial cells. What is the normal role of this factor?

AIt regulates complement activation on host cellsBIt expresses tissue-restricted self antigens so autoreactive T cells are deletedCIt generates the diversity of the T-cell receptorDIt switches immunoglobulin classes in germinal centres

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

The answer and the reasoning

B. It expresses tissue-restricted self antigens so autoreactive T cells are deleted

The AIRE gene allows medullary thymic epithelial cells to express many tissue-specific self antigens. T cells that react strongly to them are deleted or diverted to regulatory fates, so loss of AIRE causes polyendocrine autoimmunity (APECED).

Option by option

A. It regulates complement activation on host cells
Complement regulation is carried out by factors such as DAF and factor H.
B. It expresses tissue-restricted self antigens so autoreactive T cells are deleted (correct)
Correct. AIRE displays peripheral self antigens in the thymus for negative selection.
C. It generates the diversity of the T-cell receptor
T-cell receptor diversity arises from RAG-mediated recombination.
D. It switches immunoglobulin classes in germinal centres
Class switching depends on AID and CD40 signalling, not AIRE.

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.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is B, It expresses tissue-restricted self antigens so autoreactive T cells are deleted. The AIRE gene allows medullary thymic epithelial cells to express many tissue-specific self antigens.

Why is "It regulates complement activation on host cells" not the answer?

Complement regulation is carried out by factors such as DAF and factor H.

Why is "It generates the diversity of the T-cell receptor" not the answer?

T-cell receptor diversity arises from RAG-mediated recombination.

Why is "It switches immunoglobulin classes in germinal centres" not the answer?

Class switching depends on AID and CD40 signalling, not AIRE.

What concept does this question test?

It tests Blood and immunity: central tolerance and AIRE in Physiology. T cells that react strongly to them are deleted or diverted to regulatory fates, so loss of AIRE causes polyendocrine autoimmunity (APECED).

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 Blood and immunity: central tolerance and AIRE?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.