Which type of hypersensitivity reaction is commonly associated with asthma?

• A. Type 1 hypersensitivity reaction mediated by IgE
• B. Type 2 hypersensitivity reaction mediated by IgG
• C. Type 3 hypersensitivity reaction involving immune complexes
• D. Type 4 hypersensitivity reaction mediated by T cells

Answer: (A)

Asthma is primarily linked to a type of hypersensitivity reaction known as Type 1 hypersensitivity, which is mediated by Immunoglobulin E (IgE). In this condition, exposure to allergens leads to the sensitization of B cells, which then produce IgE antibodies specific to these allergens. The subsequent exposure to the same allergens results in the binding of IgE to mast cells and basophils, facilitating their activation and the release of various inflammatory mediators, such as histamines and leukotrienes. This cascade of events causes symptoms characteristic of asthma, including bronchoconstriction, airway inflammation, and increased mucus production.

The involvement of IgE in allergic reactions explains the immediate hypersensitivity response observed in asthma, making it a classic example of Type 1 hypersensitivity. This form of reaction is well-studied and recognized in the context of asthma, highlighting the importance of immunological mechanisms in the pathophysiology of respiratory conditions.