Which of the following immunoglobulin will be increased in a person with an allergy?

JODHPUR AIIMS SNO-2018

Applied Microbiology & Infection control

Easy

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

Immunoglobulin E (IgE) is the primary antibody associated with Type I hypersensitivity reactions, which are commonly known as allergies.
IgE molecules bind to receptors on the surface of mast cells and basophils.
When an allergen (like pollen or dust) enters the body, it cross-links the IgE antibodies, triggering the cells to degranulate and release histamine and other inflammatory mediators.
This release of mediators causes the classic symptoms of an allergic reaction, such as itching, swelling, sneezing, and bronchoconstriction.

Option B: IgG is the most abundant antibody and is primarily involved in the secondary immune response, providing long-term immunity. It is not the primary mediator of allergic reactions.
Option C: IgM is the first antibody produced during a primary (initial) infection. Its presence indicates a recent or active infection, not an allergic response.
Option D: IgA is found in mucosal secretions like saliva, tears, and breast milk, where it acts as the first line of defense against pathogens entering through these surfaces.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Role of immunoglobulins in allergic reactions as background academic context rather than a clinical decision trigger.
Nurses often manage patients with allergies. Understanding that elevated IgE levels are a key indicator helps in interpreting lab results and educating patients about their condition and treatment, such as antihistamines.
In clinical practice, serum IgE levels can be measured to help diagnose and monitor allergic diseases like asthma, allergic rhinitis, and atopic dermatitis.
What if? If a patient's lab results showed elevated IgM instead of IgE, the nurse's interpretation would shift from an allergy to a possible recent or ongoing infection, prompting different assessments and interventions (e.g., monitoring for fever, sepsis).

How to Approach the Question

First, identify the core concept of the question, which is the relationship between immunoglobulins and allergies.
Recall the specific functions of the different classes of immunoglobulins (a common mnemonic is GAMED - IgG, IgA, IgM, IgE, IgD).
Focus on the keyword 'allergy'. Associate this with Type I hypersensitivity reactions.
Connect Type I hypersensitivity to the specific immunoglobulin responsible, which is IgE.
Evaluate the other options (IgG, IgM, IgA) and recall their primary roles (long-term immunity, acute infection, mucosal immunity, respectively) to confirm they are not the primary mediators of allergy.

Concept Tested & Keywords

QRVykDC9yGrAmvtBMKrJdo

E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) pp. 350-352, 358-360

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1388-1390