Booster Injection with Birch Pollen Extract Activates B-Cellular Memory Responses in Patients Having Completed...

Area of Science:

• Immunology
• Allergy Research
• Vaccinology

Background:

• Allergen immunotherapy (AIT) induces blocking IgG antibodies for tolerance in IgE-mediated allergies.
• Antibody levels decrease after AIT cessation, risking loss of tolerance.

Purpose of the Study:

• To investigate the effect of a single allergen booster on B-cell memory in birch pollen (BP)-allergic patients who completed AIT.
• To assess if a booster can reinforce allergen tolerance after AIT.

Main Methods:

• 25 AIT-treated BP-allergic patients received one BP allergen injection.
• Measured Bet v 1-specific IgG-secreting cells (ASC), serum IgG, IgG4, IgE antibodies, and IgG/IgG4 blocking activity.
• Compared results with 12 patients undergoing conventional AIT.

Main Results:

• A single BP injection significantly increased Bet v 1-specific ASC, IgG/IgG4 antibodies, and allergen-blocking activity 2-4 weeks post-injection.
• The booster elicited a stronger B-cell response compared to conventional AIT up-dosing.
• Clinical responses were assessed using visual analog scales.

Conclusions:

• Allergen booster injections effectively activate B-cell memory.
• This activation is linked to increased blocking IgG/IgG4 antibodies, reinforcing allergen tolerance.
• A single booster may be a strategy to sustain tolerance post-AIT.