University College Dublin, School of Veterinary Medicine, Belfield, Dublin 4, Ireland.
University College Dublin, School of Agriculture and Food Science, Belfield, Dublin 4, Ireland.
Vet Parasitol. 2023 Jul;319:109954. doi: 10.1016/j.vetpar.2023.109954. Epub 2023 May 6.
Canine demodicosis is a common skin disease seen in companion animal practice that results from an overpopulation of the commensal Demodex mite species. Common predisposing factors to the development of canine demodicosis include immunosuppressive diseases, such as neoplasia and hypothyroidism, and administration of immunosuppressive therapies, such as corticosteroids. Despite this, the pathogenesis of development of canine demodicosis remains unclear. Previous studies have implicated a role for increased expression of toll like receptor 2 (TLR2), increased production of interleukin (IL)-10) and T cell exhaustion. Here, we investigate gene expression of formalin fixed paraffin embedded skin samples from twelve cases of canine demodicosis in comparison to twelve healthy controls, using a 770 gene panel (NanoString Canine IO Panel). Results show an increase in the T cell population, specifically Th1 and Treg cells in dogs with demodicosis. In addition, while there is an upregulation of immunosuppressive cytokines such as IL-10 and IL-13, there is also an upregulation of immune check point molecules including PD-1/PD-L1 and CTLA-4. These findings suggest that Demodex spp. mites are modulating the host immune system to their advantage through upregulation of several immune tolerance promoting pathways.
犬蠕形螨病是伴侣动物临床中常见的皮肤疾病，由共生的蠕形螨过度繁殖引起。犬蠕形螨病发展的常见诱发因素包括免疫抑制性疾病，如肿瘤和甲状腺功能减退症，以及免疫抑制治疗的应用，如皮质类固醇。尽管如此，犬蠕形螨病的发病机制仍不清楚。先前的研究表明，Toll 样受体 2（TLR2）表达增加、白细胞介素（IL）-10 产生增加和 T 细胞耗竭都与犬蠕形螨病有关。在这里，我们使用 770 个基因表达谱（NanoString Canine IO 面板），对 12 例犬蠕形螨病病例与 12 例健康对照的福尔马林固定石蜡包埋皮肤样本的基因表达进行了研究。结果表明，患有蠕形螨病的犬的 T 细胞群体，特别是 Th1 和 Treg 细胞增加。此外，虽然免疫抑制性细胞因子如 IL-10 和 IL-13 的表达上调，但免疫检查点分子如 PD-1/PD-L1 和 CTLA-4 的表达也上调。这些发现表明，蠕形螨属螨通过上调几种促进免疫耐受的途径来调节宿主免疫系统以利于其自身。
