Alterations of the nasal and oral microbiota in multiple sclerosis.

Background: While changes in the gut microbiota have been reported in multiple sclerosis (MS), little is known about the nasal and oral microbiota, which are important modulators of the mucosal immune system. The gingival microbiota can drive systemic inflammation, the pharyngeal microbiota can lead to autoimmune-mediated neurologic diseases, and altered nasal bacterial toxigenic genes are reported in active MS.

Methods: We investigated nasal, gingival, and oropharyngeal microbiota from 69 MS to 40 healthy control subjects by 16S rRNA sequencing and identified site-specific microbiota differences in both the nasal and oral microbiota related to relapsing and progressive MS. We identified microbes associated with MS diagnosis, disease progression, disease modifying therapy, smoking, and anatomical site using linear regression analysis while controlling for confounding factors and subject demographics.

Findings: We identified site-specific microbiota differences in both the nasal and oral microbiota related to relapsing and progressive MS. Using baseline microbiota samples and clinical outcomes over time, we identified potential beneficial microbes, including Dolosigranulum pigrum in the nasal microbiota and Prevotella sp. in the oral microbiota, as well as potential detrimental Streptococcus sp. in the oral microbiota.

Interpretation: Taken together, our data suggest that nasal and oral microbiota are altered in MS, are linked to the disease course and provide an avenue to better understand MS pathogenesis and treatment.

Funding: This work was supported by the Nancy Davis Race to Erase MS Young Investigator Award (LMC), NIH/NINDS R01NS087226 (HLW), Water Cove Charitable Foundation (HLW), and the Clara E. and John H. Ware Jr. Foundation (HLW, LMC).