Allergen-specific immunotherapy provides lasting benefit in allergic rhinitis chiefly because it:

• A Permanently depletes mucosal mast cells
• B Causes irreversible desensitisation of unmyelinated C fibres
• C Converts circulating allergen-specific IgE into IgM
• D Induces allergen-specific IgG4 blocking antibodies with a shift from Th2 to T regulatory responses ✓

Explanation

Repeated controlled exposure to escalating allergen doses generates allergen-specific IgG4, which competes with IgE for antigen and prevents mast cell and basophil activation. It also drives a shift away from the Th2 cytokine profile toward T regulatory cells producing IL-10 and TGF-beta, dampening the allergic cascade. IgE is not converted to another class, mast cell numbers are not abolished, and nerve desensitisation plays no role in its mechanism.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.