Immunodeficiency: leukocyte adhesion deficiency: 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 · Immunodeficiency: leukocyte adhesion deficiency

Sample item

A newborn has delayed separation of the umbilical cord beyond 3 weeks, omphalitis without pus formation and a neutrophil count of 40,000 per microlitre. Which defect is responsible?

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

The answer and the reasoning

B. Mutation of the CD18 beta-2 integrin subunit, impairing neutrophil adhesion and transmigration

In leukocyte adhesion deficiency type 1, CD18 (ITGB2) is defective, so neutrophils cannot adhere firmly to the endothelium or leave the vessels. Neutrophils therefore pile up in the blood, with neutrophilia, while infections at the tissue site lack pus. Delayed cord separation and recurrent bacterial infections are typical.

Option by option

  • A. Mutation of LYST, impairing lysosomal trafficking

    LYST mutation causes Chediak-Higashi syndrome, with giant lysosomal granules and albinism.

  • B. Mutation of the CD18 beta-2 integrin subunit, impairing neutrophil adhesion and transmigration (correct)

    Correct. Failure of integrin-mediated adhesion explains neutrophilia without pus and delayed cord separation.

  • C. Mutation of BTK, impairing B-cell maturation

    BTK mutation causes agammaglobulinaemia with absent B cells, and neutrophil counts are normal.

  • D. Mutation of NADPH oxidase, impairing the oxidative burst

    NADPH oxidase defects cause chronic granulomatous disease with abscess formation and granulomas.

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 B, Mutation of the CD18 beta-2 integrin subunit, impairing neutrophil adhesion and transmigration. In leukocyte adhesion deficiency type 1, CD18 (ITGB2) is defective, so neutrophils cannot adhere firmly to the endothelium or leave the vessels.

Why is "Mutation of LYST, impairing lysosomal trafficking" not the answer?

LYST mutation causes Chediak-Higashi syndrome, with giant lysosomal granules and albinism.

Why is "Mutation of BTK, impairing B-cell maturation" not the answer?

BTK mutation causes agammaglobulinaemia with absent B cells, and neutrophil counts are normal.

Why is "Mutation of NADPH oxidase, impairing the oxidative burst" not the answer?

NADPH oxidase defects cause chronic granulomatous disease with abscess formation and granulomas.

What concept does this question test?

It tests Immunodeficiency: leukocyte adhesion deficiency in Pathology. Neutrophils therefore pile up in the blood, with neutrophilia, while infections at the tissue site lack pus. Delayed cord separation and recurrent bacterial infections are typical.

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 Immunodeficiency: leukocyte adhesion deficiency?

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.