Since their discovery about 10 years ago, Th9 cells have been increasingly linked to allergic pathologies. Within this review, we summarize the current knowledge on associations between Th9 cells and allergic diseases and acknowledge Th9 cells as important targets in future treatment of allergic diseases. However, until today, it is not fully understood how these Th9 cell responses are modulated. We describe current literature suggesting that these Th9 cell responses might be stimulated by microbial species such as Staphylococcus aureus and Candida albicans, while on the other hand, microbial and dietary compounds such as retinoic acid (RA), butyrate and vitamin D show suppressive capacity on allergy‐related Th9 responses. By reviewing this recent research, we provide new insights into the modulating capacity of the microbiota on Th9 cell responses. Consequently, microbial and dietary factors may be used as innovative tools to target Th9 cells in the treatment of allergic diseases. However, further research is needed to elucidate the mechanisms behind these interactions in order to translate this knowledge into clinical allergy settings.

中文翻译：

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Th9细胞在变应性疾病中的作用：微生物群？

自大约10年前发现以来，Th9细胞已越来越多地与过敏性病理联系在一起。在这篇综述中，我们总结了有关Th9细胞与过敏性疾病之间关系的当前知识，并承认Th9细胞是将来治疗过敏性疾病的重要靶标。然而，直到今天，仍不完全了解如何调节这些Th9细胞反应。我们描述了当前的文献，暗示这些Th9细胞反应可能受到金黄色葡萄球菌和白色念珠菌等微生物物种的刺激另一方面，微生物和膳食化合物，例如视黄酸（RA），丁酸和维生素D对过敏相关的Th9反应具有抑制作用。通过审查此最新研究，我们提供了对Th9细胞反应的微生物群调节能力的新见解。因此，微生物和饮食因素可以用作在过敏性疾病治疗中靶向Th9细胞的创新工具。然而，需要进一步的研究来阐明这些相互作用背后的机制，以便将这些知识转化为临床过敏症。