The biodiversity of the mycobiome, an important component of the oral microbial community, and the roles of fungal–bacterial and fungal–immune system interactions in the pathogenesis of oral lichen planus (OLP) remain largely uncharacterized. In this study, we sequenced the salivary mycobiome and bacteriome associated with OLP. First, we described the dysbiosis of the microbiome in OLP patients, which exhibits lower levels of fungi and higher levels of bacteria. Significantly higher abundances of the fungi Candida and Aspergillus in patients with reticular OLP and of Alternaria and Sclerotiniaceae_unidentified in patients with erosive OLP were observed compared to the healthy controls. Aspergillus was identified as an “OLP-associated” fungus because of its detection at a higher frequency than in the healthy controls. Second, the co-occurrence patterns of the salivary mycobiome–bacteriome demonstrated negative associations between specific fungal and bacterial taxa identified in the healthy controls, which diminished in the reticular OLP group and even became positive in the erosive OLP group. Moreover, the oral cavities of OLP patients were colonized by dysbiotic oral flora with lower ecological network complexity and decreased fungal–Firmicutes and increased fungal–Bacteroidetes sub-networks. Third, several keystone fungal genera (Bovista, Erysiphe, Psathyrella, etc.) demonstrated significant correlations with clinical scores and IL-17 levels. Thus, we established that fungal dysbiosis is associated with the aggravation of OLP. Fungal dysbiosis could alter the salivary bacteriome or may reflect a direct effect of host immunity, which participates in OLP pathogenesis.

真菌微生物组是口腔微生物群落的重要组成部分，其生物多样性以及真菌-细菌和真菌-免疫系统相互作用在口腔扁平苔藓（OLP）发病机理中的作用仍然未知。在这项研究中，我们对与OLP相关的唾液真菌基因组和细菌组进行了测序。首先，我们描述了OLP患者中微生物组的营养不良，其表现出较低的真菌水平和较高的细菌水平。与健康对照组相比，网状OLP患者的真菌念珠菌和曲霉菌丰度较高，而糜烂性OLP患者的链霉菌和菌核菌丰度较高。曲霉被鉴定为“ OLP相关”真菌，因为它的检出频率高于健康对照组。其次，唾液霉菌菌群-细菌群的共现模式表明，在健康对照中鉴定出的特定真菌和细菌类群之间存在负相关性，在网状OLP组中有所减少，而在侵蚀性OLP组中甚至呈阳性。此外，OLP患者的口腔中充满了生态系统复杂性较低，真菌-拟杆菌和真菌-拟杆菌亚组的减少的营养不良的口腔菌群。第三，几个主要的真菌属（Bovista，Erysiphe，Psathyrella等）显示出与临床评分和IL-17水平显着相关。因此，我们确定真菌营养不良与OLP的恶化有关。真菌营养不良可能会改变唾液细菌，或者可能反映宿主免疫的直接作用，而宿主免疫参与了OLP发病机理。