Immunology: lymph node paracortex: 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: lymph node paracortex

Sample item

A lymph node biopsy from an infant with a 22q11.2 deletion and absent thymic tissue is examined. Which lymph node region is expected to be depleted of lymphocytes?

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

The answer and the reasoning

B. Paracortex

The paracortex is the T cell zone of the lymph node, populated by T cells and dendritic cells, so it is depleted when thymic development fails. Follicles are the B cell areas and the medullary cords contain plasma cells. In thymic aplasia, B cell areas are relatively preserved.

Option by option

  • A. Medullary cords

    Medullary cords contain plasma cells and macrophages, which are not primarily T cell dependent.

  • B. Paracortex (correct)

    Correct. T cells reside in the paracortex, which is poor in thymic aplasia.

  • C. Subcapsular sinus

    The subcapsular sinus is a lymph channel and not a lymphocyte zone.

  • D. Primary follicles of the cortex

    Primary follicles contain B cells, which are present in thymic aplasia.

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.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Paracortex. The paracortex is the T cell zone of the lymph node, populated by T cells and dendritic cells, so it is depleted when thymic development fails.

Why is "Medullary cords" not the answer?

Medullary cords contain plasma cells and macrophages, which are not primarily T cell dependent.

Why is "Subcapsular sinus" not the answer?

The subcapsular sinus is a lymph channel and not a lymphocyte zone.

Why is "Primary follicles of the cortex" not the answer?

Primary follicles contain B cells, which are present in thymic aplasia.

What concept does this question test?

It tests Immunology: lymph node paracortex in Microbiology. Follicles are the B cell areas and the medullary cords contain plasma cells. In thymic aplasia, B cell areas are relatively preserved.

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: lymph node paracortex?

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.