Which immunoglobulin plays a role in the hypersensitivity reaction such as allergy, asthma, and also protects the body from helminths pathogens?

Appeared in: UPRVUNL - 2021

Explanation

Immunoglobulin E (IgE) is the class of antibody responsible for mediating Type I hypersensitivity reactions.
These reactions include common allergic conditions such as asthma, allergic rhinitis (hay fever), and anaphylaxis.
IgE achieves this by binding to receptors on mast cells and basophils. When an allergen cross-links these IgE molecules, it triggers the cells to degranulate and release histamine and other inflammatory mediators.
In addition to its role in allergies, IgE is a critical component of the immune response to parasitic worm (helminth) infections, where it helps activate eosinophils to attack the parasite.

Option A: IgG is the most abundant immunoglobulin and is primarily involved in the secondary immune response, providing long-term immunity. It does not mediate immediate hypersensitivity reactions.
Option B: IgA is the main immunoglobulin found in mucosal secretions like saliva, tears, and breast milk. Its primary role is to provide localized protection on mucosal surfaces.
Option D: IgM is the first antibody produced during an initial (primary) immune response. Its large pentameric structure makes it very effective at activating the complement system and agglutinating pathogens.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Functions of Immunoglobulins as background academic context rather than a clinical decision trigger.
Understanding the role of IgE is fundamental for nurses in managing patients with allergic conditions. This includes patient education on allergen avoidance, administering antihistamines, and recognizing the signs of anaphylaxis.
Elevated IgE levels in a blood test can be a diagnostic marker for atopic (allergic) conditions. Nurses may be involved in explaining these lab results to patients.
In cases of severe allergic reactions (anaphylaxis), nurses must be prepared to administer epinephrine immediately, which counteracts the life-threatening effects of massive histamine release.

How to Approach the Question

First, identify the key terms in the question: 'immunoglobulin', 'hypersensitivity reaction', 'allergy', 'asthma', and 'helminths'.
This is a factual recall question that requires knowledge of the specific functions of the different classes of immunoglobulins.
Recall the primary role of each immunoglobulin option: IgG (long-term/placental), IgA (mucosal), IgE (allergies/parasites), and IgM (acute/primary response).
Match the functions described in the question (allergy and helminth protection) with the correct immunoglobulin.
The combination of 'allergy/asthma' and 'helminths' is a classic description of IgE's function, making it the correct choice.

Concept Tested & Keywords

Concept Tested: Functions of Immunoglobulins
Stem keywords: immunoglobulin, hypersensitivity reaction, allergy, asthma, helminths
Lead-in keywords: Which

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Practise the full UPRVUNL - 2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.