Treating allergies via skin - Recent advances in cutaneous allergen immunotherapy

The Hydrogel Based Allergen-Coated Gold Nanoparticles for Topical Administration: A Possible Epicutaneous Immunotherapy in Pollen-Sensitized Mice?

BACKGROUND

The rapid uptake of antigens by antigen-presenting cells (APCs) and their migration to draining lymph nodes in the initial hours after antigen administration in epicutaneous allergen specific immunotherapy (EPIT) prompted us to investigate whether the topical administration of allergens without patch application could alleviate allergy in pollen-sensitized mice. We evaluated the immunotherapeutic effect of topically administering hydrogel-based Gold nanoparticles (AuNPs) loaded with a total extract of Platanus orientalis pollen (Pla. ext (50 μg)-AuNPs) on intact skin.

METHODS

Mice sensitized to P. orientalis pollen were divided into three groups and treated with Pla. ext (50 μg)-AuNPs: 1) patch with Pla. ext (50 μg)-AuNPs, 2) patch with Pla. ext (50 μg)-AuNPs in combination with hydrogel, and 3) topical application of Pla. ext (50 μg)-AuNPs in combination with hydrogel. The immunotherapeutic effects were evaluated by measuring serum specific and total IgE antibodies, total cell and eosinophil count in nasopharyngeal lavage fluid, cytokines in the supernatants of re-stimulated splenocytes by the total extract, and histological examination of lung and nasal mucosa.

RESULTS

Topical administration of Pla. ext (50 μg)-AuNPs, like patch-based administration, significantly downregulated specific and total IgE and IL-4 production, promoted secretion of IFN-γ and IL-10, markedly reduced the number of inflammatory cells, particularly eosinophils, in nasopharyngeal lavage fluid (p < .05), and inhibited inflammation and pathological damage in lung and nasal mucosa.

CONCLUSION

Our results suggest that topical administration of AuNPs loaded with P. orientalis total pollen extract on intact skin could be a potential application for EPIT in the P. orientalis pollen -sensitized mice.

Development of a mini pig model of peanut allergy

Introduction

The prevalence of peanut allergies is increasing, emphasizing the need for an animal model to enhance our understanding of peanut allergy pathogenesis and to advance diagnostic tools and therapeutic interventions. While mice are frequently used as model organisms, their allergic responses do not fully mirror those observed in humans, warranting the exploration of a higher animal model. The porcine gastrointestinal system closely resembles that of humans, and exhibits allergy symptoms akin to human responses, making pigs a promising model for peanut allergy research.

Methods

In this study we compared two allergen sensitization protocols involving either topical allergen application after repeated tape stripping (TS) or intraperitoneal (IP) injections to induce peanut-specific allergy and anaphylaxis reactions in mini pigs. Mini pigs sensitized with a combination of peanut protein extract (PE) and cholera toxin (CT) through either the IP or the TS route.

Results

Sensitized pigs via both methods developed systemic PE-specific IgG and IgE responses. Following peanut challenge via the IP route, both TS- and IP-sensitized pigs displayed allergy symptoms, including lethargy, skin rashes, vomiting, and a drop in body temperature. However, respiratory distress was observed exclusively in pigs sensitized through the TS route and not in those sensitized through the IP route. However, it is noteworthy that both groups of sensitized pigs maintained peanut hypersensitivity for up to two months post-sensitization, albeit with a reduction in the severity of allergy symptoms. Importantly, both groups exhibited sustained levels of PE-specific IgG, IgE, and elevated concentrations of mast cell protease in their blood following the IP challenges.

Discussion

Overall, this study reports TS and IP as two different modes of sensitization leading to onset of peanut specific allergic reactions in mini pigs, but only the TS-sensitization led to systemic anaphylaxis (simultaneous presence of symptoms: breathing difficulty, intense skin rash, and impaired mobility). A distinctive feature of these sensitization protocols is the 100% success rate (N = 4 pigs per group) in sensitizing the subjects.