Immune fitness and biomarkers of immune function: Relationships with the oral and gut microbiome composition

Background: Immune fitness refers to the body's capacity to respond to health challenges, such as infections, by activating an appropriate immune response. The aim of the current study was to investigate the relationship between oral and gut microbiota community structure and immune fitness scores. Methods: Stool and saliva samples were collected to assess compositions of both oral and gut microbiota. Immune fitness was assessed with a single-item scale ranging from 0 (very poor) to 10 (excellent). Additionally, saliva samples were analyzed to measure the concentrations (pg/ml) of pro-inflammatory biomarkers interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-α). Spearman's correlations were computed between microbiota abundance, immune fitness, and salivary biomarker levels. Bootstrapping was used to adjust for the relatively small sample size in the correlation analysis. Results: group (r = -0.504). Conclusion: Self-reported immune fitness is associated with the oral and gut microbiota community. The findings demonstrate the importance of microbiota in immune function and support the use of self-assessment scales to evaluate immune fitness.