Abstract
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.