Efficacy of Laser Facilitated Epicutaneous Immunotherapy with Dermatophagoides Pteronyssinus Depigmented Extract in a Mouse Model of Allergy

Epicutaneous immunotherapy (EPIT) is being investigated as a promising alternative for the treatment of type I allergies. We hypothesized that a house dust mite depigmented extract EPIT would show therapeutic efficacy in a mouse model of allergy Mice sensitized against Dermatophagoides pteronyssinus were treated with depigmented D. pteronyssinus extract via laser-generated skin micropores or subcutaneous injection with or without alum. Following aerosol challenges, lung function was determined by whole-body plethysmography and bronchoalveolar lavage fluid (BALF) was analyzed for cellular composition by flow cytometry. D. pteronyssinus specific IgG subclass antibodies were measured by ELISA. Serum IgE was determined by rat basophil leukemia cell assay whereas cell-bound IgE and blocking capacity of IgG were determined by basophil activation test. Cultured splenocytes from treated mice were analyzed for cytokine secretion by flow cytometry. In all treatment groups a significant reduction of enhanced pause compared to pre-treatment values was observed. This improvement correlated with a reduction of cellular infiltrate (eosinophils and CD4 T cells) into BALF. EPIT also resulted in a significantly higher increase in the percentage of FoxP3+ T cells compared to untreated mice. Treatment without alum led to a significant suppression of IgE. IgG blocking activity correlated with IgG ELISA levels in all groups, but was significantly higher for EPIT. Treatments also resulted in significant suppression of cytokine secretion by splenocytes. Allergen-specific immunotherapy with depigmented D. pteronyssinus extract via laser-generated skin micropores offers a safe and effective treatment option for mite-induced allergy.