The role of oral microbiome in pemphigus vulgaris.

While the impact of oral microbiome dysbiosis on autoimmune diseases has been partially investigated, its role on bullous diseases like Pemphigus Vulgaris (PV) is a totally unexplored field. This study aims to present the composition and relative abundance of microbial communities in both healthy individuals and patients with oral PV lesions. Ion Torrent was used to apply deep sequencing of the bacterial 16S rRNA gene to oral smear samples of 15 healthy subjects and 15 patients. The results showed that the most dominant phyla were Firmicutes (55.88% controls-c vs 61.27% patients-p, p value = 0.002), Proteobacteria (9.17%c vs 12.33%p, p value = 0.007) and Fusobacteria (3.39%c vs 4.09%p, p value = 0.03). Alpha diversity showed a significant difference in the number of genera between patients and controls (p value = 0.04). Beta diversity showed statistical differences in the microbial community composition between two groups. Fusobacterium nucleatum, Gemella haemolysans and Parvimonas micra were statistically abundant in patients. We noticed the characteristic fetor coming out of oral PV lesions. Most of anaerobic bacteria responsible for oral halitosis are periopathogenic. Though, only F. nucleatum and P. micra were differentially abundant in our patients. Especially, F. nucleatum has been reported many times as responsible for bad breath. Furthermore, Streptococcus salivarius and Rothia mucilaginosa, species mostly associated with clean breath, were found in relative abundance in the healthy group. Consequently, the distinct malodor observed in PV patients might be attributed either to the abundance of F. nucleatum and P. micra and/or to the lower levels of S. salivarius and R. mucilanginosa in oral lesions.