(559b) Microneedles for Allergen Immunotherapy: In Vivo Efficacy in Mouse Models of Airway Allergy

Introduction: Allergies are increasing worldwide. Respiratory allergy can be managed with allergen specific immunotherapy (ASI), which is currently administered through subcutaneous (SC) injections totaling in excess of 60, and spread over 4-5 years. This discourages many patients, and those who decide to get ASI show poor patient compliance. We hypothesized that microneedles coated with airway allergens could offer an alternative approach for ASI, one that would be painless and easy to administer, perhaps even at home after several initial visits to the clinic. In this study we show efficacy of cutaneous immunotherapy via microneedles in a mouse model of airway allergy.

Methods: Mouse models of airway allergy were created using ovalbumin and house dust mite allergen Der p1. Allergic mice were treated with either i) a subcutaneous injection of allergen formulated with alum, or ii) microneedles coated with allergen, or iii) microneedles coated with allergen and CpG as adjuvant. Naïve mice and allergic but untreated mice were used as control groups. Antibody responses were measured using ELISA. After treatment, the mice were challenged with the allergen to assess protection of treatments from allergen exposure. Allergy clinical scores, body temperature, and serum histamine levels were monitored to evaluate severity of reaction to the allergen. Lung cellular infiltrates were also analyzed in the asthma mouse model.

Results: Mice treated with microneedles generated high allergen-specific antibody responses. Secreted cytokines demonstrated a Th1 biased immune response, which is considered to be beneficial for allergy immunotherapy. Allergic mice that were treated with allergen-coated microneedles were protected from allergic reaction to allergen challenge similar to or better than the SC ASI treated mice. In contrast untreated mice exhibited severe symptoms of allergic reactions.

Conclusion: This is the first demonstration of microneedles for allergen immunotherapy, paving the way for an easy to apply and convenient approach of allergy treatment.