The skin is a key route of human exposure to nanomaterials, which typically occurs simultaneously with exposure to other chemical and environmental allergen. However, little is known about the hazards of nanomaterial exposure via the skin, particularly when accompanied by exposure to other substances. Repeated topical treatment of both ears and the shaved upper back of NC/Nga mice, which are models for human atopic dermatitis (AD), with a mixture of mite extract and silica nanoparticles induced AD-like skin lesions. Measurements of ear thickness and histologic analyses revealed that cutaneous exposure to silica nanoparticles did not aggravate AD-like skin lesions. Instead, concurrent cutaneous exposure to mite allergens and silica nanoparticles resulted in the low-level production of allergen-specific IgGs, including both the Th2-related IgG1 and Th1-related IgG2a subtypes, with few changes in allergen-specific IgE concentrations and in Th1 and Th2 immune responses. In addition, these changes in immune responses increased the sensitivity to anaphylaxis. Low-level IgG production was induced when the mice were exposed to allergen–silica nanoparticle agglomerates but not when the mice exposed to nanoparticles applied separately from the allergen or to well-dispersed nanoparticles. Our data suggest that silica nanoparticles themselves do not directly affect the allergen-specific immune response after concurrent topical application of nanoparticles and allergen. However, when present in allergen-adsorbed agglomerates, silica nanoparticles led to a low IgG/IgE ratio, a key risk factor of human atopic allergies. We suggest that minimizing interactions between nanomaterials and allergens will increase the safety of nanomaterials applied to skin.

中文翻译：

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皮肤暴露于二氧化硅纳米颗粒和过敏原的团聚体会导致偏向IgE的免疫反应，并增加小鼠对过敏反应的敏感性。

皮肤是人类接触纳米材料的关键途径，通常会与其他化学和环境过敏原同时发生。然而，人们对纳米材料经皮肤暴露的危害知之甚少，尤其是在伴随其他物质暴露的情况下。用螨提取物和二氧化硅纳米颗粒的混合物反复重复治疗耳朵和NC / Nga小鼠的剃毛后背（这是人特应性皮炎（AD）的模型），并掺入螨虫提取物和二氧化硅纳米颗粒，以诱导AD样皮肤病变。耳朵厚度的测量和组织学分析表明，皮肤接触二氧化硅纳米粒子不会加剧AD样皮肤病变。相反，同时在皮肤上接触螨过敏原和二氧化硅纳米颗粒会导致低水平产生过敏原特异性IgG，包括Th2相关IgG1和Th1相关IgG2a亚型，在变应原特异性IgE浓度以及Th1和Th2免疫应答方面几乎没有变化。此外，免疫反应的这些变化增加了对过敏反应的敏感性。当小鼠暴露于过敏原-二氧化硅纳米颗粒附聚物时，会诱导低水平的IgG产生，但当小鼠暴露于与过敏原分开应用的纳米颗粒或分散良好的纳米颗粒时，则不会诱导产生。我们的数据表明，在同时局部应用纳米颗粒和过敏原后，二氧化硅纳米颗粒本身不会直接影响过敏原特异性的免疫反应。然而，当存在于过敏原吸附的团聚体中时，二氧化硅纳米颗粒导致低的IgG / IgE比，这是人类特应性过敏的关键危险因素。