The immunoglobulin that is elevated in individuals with allergy is:

Correct option is A

Immunoglobulin E (IgE) is the antibody most commonly associated with allergic reactions. Upon exposure to allergens, IgE binds to mast cells and basophils, triggering the release of histamines and other chemicals, which lead to allergy symptoms like itching, swelling, and bronchoconstriction. Elevated IgE levels are a clinical marker in conditions such as asthma, eczema, and hay fever.
Explanation of options: (a) Immunoglobulin E – This is the correct answer. IgE is directly involved in hypersensitivity (Type I) reactions, making it a key biomarker for allergic conditions. (b) Immunoglobulin A – IgA is found in mucosal areas such as the respiratory and gastrointestinal tracts and plays a role in local immunity, not in allergic responses. (c) Immunoglobulin D – IgD is involved in the initiation of B-cell activation but has no known significant role in allergic responses or hypersensitivity. (d) Immunoglobulin M – IgM is the first antibody produced in response to an infection. It is part of the primary immune response, not typically elevated in allergy.