Capture of cashew allergen by skin dendritic cells is enhanced in cashew-sensitized mice following epicutaneous delivery Running title: Sensitization to cashew leads to increased epicutaneous delivery of cashew allergenPierre-Louis Hervé1*, Benjamin Pelletier1, Noémie Assoun1, Nathalie Oreal1, Audrey Perrin1, Jean-Louis Labernardière1, Hugh A Sampson2* Correspondence should be addressed to P-L.H. ([email protected]; +33 1 84 86 11 30)1 DBV Technologies, 177-181 avenue Pierre Brossolette, 92120 Montrouge, France2 DBV Technologies, 12 East 49th Street Tower 49, Suite 4001, New York, NY 10017, USAMain text word count: 595

Background: The prevalence of tree nut allergy has increased worldwide, and cashew has become one of the most common food allergens. More critically, cashew allergy is frequently associated with severe anaphylaxis. Despite the high medical need, no approved treatment is available and strict avoidance and preparedness for prompt treatment of allergic reactions are considered dual standard of care. In the meantime, Phase III study results suggest investigational epicutaneous immunotherapy (EPIT) may be a relevant and safe treatment for peanut allergy and may improve the quality of life for many peanut allergic children. Objective: We aimed to evaluate the capacity of EPIT to provide protection against cashew-induced anaphylaxis in a relevant mouse model. Methods: A mouse model of IgE-mediated cashew anaphylaxis was first developed. Based upon this model, the efficacy of EPIT was evaluated by applying patches containing cashew allergens to cashew-sensitized mice. Cashew-specific antibody titers were measured throughout treatment. Treated mice were challenged orally to cashew and anaphylactic symptoms were monitored. Additionally, plasma levels of mast-cell proteases (mMCP)-1/7 were quantified from blood samples collected after challenge to evaluate IgE-induced mast-cell activation. Results: EPIT significantly decreased anaphylactic symptoms following challenge and increased cashew-specific IgG2a (equivalent of human IgG1). Interestingly, this protection was associated with a sharp decrease in mast-cell reactivity. Conclusion: We demonstrate that EPIT markedly reduced IgE-mediated allergic reactions in a mouse model of cashew allergy, which suggests that EPIT may be a relevant approach to treating cashew allergy.