Which of the following antibodies are produced in allergic disorders?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Microbiology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Immunoglobulin E (IgE) is the class of antibody primarily produced in response to allergens.
IgE binds to high-affinity receptors on the surface of mast cells and basophils.
When an allergen cross-links these IgE molecules, it triggers the degranulation of these cells, releasing histamine and other inflammatory mediators.
This process results in the clinical manifestations of Type I hypersensitivity reactions, such as allergic rhinitis, asthma, urticaria, and anaphylaxis.

Option A: IgA is the main antibody found in mucous secretions, including those in the respiratory and gastrointestinal tracts. Its primary role is to provide localized protection on mucosal surfaces.
Option B: IgD is present in very small amounts in the blood and is primarily found on the surface of B-lymphocytes. It is thought to function as a B-cell receptor, but it is not the main antibody involved in allergic reactions.
Option C: IgM is the first antibody produced during an initial (primary) immune response to an infection. Its presence typically indicates a recent or acute infection.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Function of Immunoglobulins in Allergic Disorders as background academic context rather than a clinical decision trigger.
Understanding that IgE mediates allergic reactions is fundamental for nurses to recognize and manage allergic conditions, from mild hay fever to life-threatening anaphylaxis.
Nurses often educate patients with allergies about avoiding triggers and using medications like antihistamines, which block the effects of histamine released during an IgE-mediated reaction.
In clinical practice, a blood test measuring total serum IgE or allergen-specific IgE can be used to help diagnose allergic diseases.

How to Approach the Question

First, identify the core concept of the question, which is the relationship between specific antibodies and a particular condition (allergic disorders).
This is a factual recall question. Access your knowledge about the five main classes of immunoglobulins (IgG, IgA, IgM, IgD, IgE) and their primary functions.
Recall or look up the specific role of each antibody class. Associate IgA with mucosal immunity, IgM with the primary response, IgG with the secondary response, and IgE with allergies and parasites.
Evaluate each option against this knowledge. IgA, IgD, and IgM are not the primary antibodies involved in allergic disorders.
Select IgE, as it is the classic antibody associated with Type I hypersensitivity, which encompasses most allergic reactions.

Concept Tested & Keywords

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

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