Laser-facilitated epicutaneous immunotherapy to IgE-mediated allergy.

Allergen specific immunotherapy has been shown to be the only effective treatment for long-lasting clinical benefit to IgE-mediated allergic diseases, but a fewer than 5% of patients choose the treatment because of inconvenience and a high risk of anaphylaxis. Recently, epicutaneous allergen-specific immunotherapy (EPIT) has proven effective, yet with limitations owing to strong skin reactions. We demonstrate here safer and faster EPIT, named μEPIT, by delivering powdered allergen and adjuvants into many micropores in the epidermis. We fabricated a microarray patch fractionally coated with a powder mixture of ovalbumin (OVA) model allergen, CpG, and 1,25-dihydroxyvitamin D3 (VD3). Topical application of the patch onto laser-microperforated skin resulted in a high level of epidermal delivery while greatly minimizing allergen leakage into circulation system as compared to current subcutaneous immunotherapy (SCIT). Moreover, only three times of μEPIT over two weeks could sufficiently inhibit allergen-specific IgE responses in mice suffering OVA-induced airway hyperresponsivness (AHR), which was unattainable by eight times of SCIT over three weeks. Mechanistically, μEPIT preferably enhanced IgG2a production suggesting TH1-biased immune responses and induced a high level of T-regulatory (Treg) cells against repeated allergen sensitization. The immune tolerance was confirmed by marked reduction in airway wall thickness as well as eosinophil and neutrophil infiltration into the respiratory airway. The μEPIT represents a novel and painless technology to treat IgE-mediated allergic diseases with little local skin reaction and a minimal risk of anaphylaxis.