Respiratory medicine: omalizumab mechanism: practice question

A General Medicine 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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General Medicine · Respiratory medicine: omalizumab mechanism

Sample item

A 28-year-old with severe persistent allergic asthma has a serum IgE of 450 IU/mL and positive skin tests to perennial allergens. She has frequent exacerbations despite high-dose inhaled corticosteroid plus long-acting beta-agonist. Omalizumab is planned. How does it act?

AInhibits phosphodiesterase 4 in inflammatory cellsBBlocks interleukin-5 and reduces eosinophil survivalCBlocks the leukotriene receptor on airway smooth muscleDBinds free IgE so it cannot occupy mast cell receptors

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

The answer and the reasoning

D. Binds free IgE so it cannot occupy mast cell receptors

Omalizumab is a humanised monoclonal antibody that binds circulating IgE, lowering free IgE and the expression of high-affinity IgE receptors on mast cells and basophils. It is used in severe allergic asthma with raised IgE that is uncontrolled on high-dose therapy.

Option by option

A. Inhibits phosphodiesterase 4 in inflammatory cells
Phosphodiesterase 4 inhibition is the action of roflumilast.
B. Blocks interleukin-5 and reduces eosinophil survival
Blocking interleukin-5 is the action of mepolizumab and reslizumab.
C. Blocks the leukotriene receptor on airway smooth muscle
Leukotriene receptor blockade is the action of montelukast and zafirlukast.
D. Binds free IgE so it cannot occupy mast cell receptors (correct)
Correct. Neutralising free IgE prevents sensitisation of mast cells.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is D, Binds free IgE so it cannot occupy mast cell receptors. Omalizumab is a humanised monoclonal antibody that binds circulating IgE, lowering free IgE and the expression of high-affinity IgE receptors on mast cells and basophils.

Why is "Inhibits phosphodiesterase 4 in inflammatory cells" not the answer?

Phosphodiesterase 4 inhibition is the action of roflumilast.

Why is "Blocks interleukin-5 and reduces eosinophil survival" not the answer?

Blocking interleukin-5 is the action of mepolizumab and reslizumab.

Why is "Blocks the leukotriene receptor on airway smooth muscle" not the answer?

Leukotriene receptor blockade is the action of montelukast and zafirlukast.

What concept does this question test?

It tests Respiratory medicine: omalizumab mechanism in General Medicine. It is used in severe allergic asthma with raised IgE that is uncontrolled on high-dose therapy.

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 Respiratory medicine: omalizumab mechanism?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.