Epicutaneous immunotherapy using a new epicutaneous delivery system in mice sensitized to peanuts

Peanut allergy is a life-threatening condition for which new efficient and safe treatment is expected. We evaluated epicutaneous immunotherapy (EPIT) as a new alternative treatment for peanut allergy in sensitized mice.

Sixty BALB/c mice were sensitized by gavages with peanut protein extract (PPE) mixed with cholera toxin. An epicutaneous delivery system, coated with 100 μg PPE (Viaskin®, DBV Technologies, Paris, France), was applied to intact skin every week during 48 h (EPIT; n = 20). This group was compared with sensitized mice treated with subcutaneous immunotherapy (SCIT; n = 20), untreated sensitized mice (sham, n = 20), and naive mice (naive; n = 20). After the 8-week treatment, a histamine release test, airway hyperreactivity measurement by plethysmography, and a resistance-compliance measurement after the challenge were performed. Blood and bronchoalveolar lavage were sampled for serology, cytokines, and cytology.

Specific IgE (sIgE) increased after sensitization in the EPIT (0.26 μg/ml) and SCIT (0.21 μg/ml) groups and decreased after treatment (0.09 μg/ml, p < 0.001 and 0.06 μg/ml, p < 0.001, respectively). The IgG1/IgG2a ratio decreased in the EPIT and SCIT groups versus the sham group (3.7; p < 0.001 and 2.7; p < 0.01 and 15.1, respectively). At the higher metacholine concentration, enhanced pause values were lower in the EPIT and SCIT groups than in the sham group (7.29, 6.74, and 10.99, p < 0.01, respectively), and did not differ from that of the naive group (5.06). Resistance-compliance was reversed in the treated groups versus the sham group (p < 0.001). IL-4, IL-5, IL-13, eotaxin, and eosinophils were reduced in the BAL of the EPIT and SCIT groups versus the sham group (p < 0.001).

In peanut-sensitized mice, based on biological and physiological responses, EPIT is as efficient as subcutaneous treatment which is the reference method in immunotherapy.