Structural Analysis of Salivary Bacterial and Fungal Microbiome in Oral Lichen Planus Patients

  Objective  To explore the differences of oral mycobiome and bacteriome between the healthy controls (H) and oral lichen planus (OLP) patients, and the co-occurrence patterns of the salivary mycobiome and bacteriome and the association with host immunity.

  Methods  Saliva samples were collected from clinical OLP patients (n=35) and healthy volunteers (n=18). Microbiome DNA was extracted for bacterial 16S rRNA genes sequencing and fungal internal transcribed spacer 2 (ITS2) sequencing. Bioinformatics analysis was performed on the data.The levels of IL-17 and IL-23, two pro-inflammatory cytokines, in the saliva were examined, and their correlation with the bacteria was analyzed.

  Results  There was no significant difference in the overall community structure of the mycobiome and the bacteriome between OLP patients and healthy controls. The abundance of Prevotella and Solobacterium in the saliva bacteriome was significantly increased in the OLP group (P<0.05), and the relative abundance of Candida and Aspergillus in the saliva mycobiome was also significantly increased (P<0.05). The co-occurrence pattern of the salivary mycobiome and bacteriome showed that the aforementioned difference was not related. However, the correlation between Aspergillus and bacteria was altered in the H group and the OLP group, and co-occurrence was reduced in the latter group. The level of IL-17 in the saliva was significantly increased in the OLP group. IL-17 and clinical scores were significantly correlated with the abundance of Porphyromonas.

  Conclusion  The increased abundance of Prevotella, Solobacterium, Candida, and Aspergillus was associated with the pathogenesis of OLP, and the changes of the microbiome co-occurrence relationship and host immunity may be involved in the pathogenesis of OLP.