Dysbiosis of saliva microbiome in patients with oral lichen planus
Abstract Background : Oral microbiota is not only important for maintaining oral health but also plays a role in oral diseases. However, studies regarding microbiome changes in oral lichen planus(OLP)are very limited. Therefore, the purpose of this study was to identify the characteristic microbial profile in the saliva of OLP patients, with or without erosive lesions, and compare that with recurrent aphthous ulcer (RAU), a common oral immunological disorder that also shows multiple erosive/ulcerative lesions. Methods : Whole saliva samples were collected from 20 patients with OLP (10 each for erosive (E) and non-erosive (NE) groups), 10 patients with RAU (U group), and 10 healthy controls (C). DNA was extracted from the saliva samples, and the 16S rDNA gene V4 hypervariable region was analyzed using Illumina sequencing. Results were assessed with alpha- and beta-diversity, linear discriminant analysis (LDA) effect size, and the data was analyzed by Spearman’s rank correlation,Wilcoxon and Kruskal test. Results: We obtained 4949 operational taxonomic units from the V4 region in all saliva samples. Community composition analysis showed a clear decreased relative abundance of genera Streptococcus and Sphingomonas in saliva from RAU patients when compared to the other three groups. Relative abundance of Lautropia and Gemella were higher in E group,whereas relative abundance of Haemophilus and Neisseria were higher in NE group when compared to C group. Abiotrophia and Oribacterium were higher in OLP (combining E and NE groups), while Eikenella and Aggregatibacter were lower when compared to C group. There was statistically significance in α-diversity between E and RAU groups( p <0.05). Significant differences in β-diversity were detected in bacteria between E and C; NE and C; as well as E and NE groups. Conclusion: We found that salivary microbiome in OLP was significantly different from that found in RAU; and these changes may be related to the underlying disease process rather than presence of ulcerative/erosive lesions clinically. In addition, our findings in bacterial relative abundance in OLP were significantly different from the previously reported findings, which points to the need for further research in salivary microbiome of OLP.