ORAL MICROBIOME IN RHEUMATIC DISEASES.WHAT INVOLVEMENT?

Background: The concept of core-microbiome in health is useful for investigating the possible role of the oral microbiome in autoimmune disease, such as Rheumatoid Arthritis, Spondyloarthritis, Sjogren Syndrome or Systemic Sclerosis (SSc), whose pathogenesis has not been fully understood. Environmental factors and certain genetic backgrounds have been proposed. Among the various environmental factors, the microbiota stands out, the entire composition of microorganisms, mainly bacteria but also fungi and viruses, which populate the human body. Objectives: The aim of the study was to verify whether there were quantitative differences between the microorganisms present in the oral cavity, in particular between the lactobacillus spp., of patients with SSc compared to those present in the oral cavity of healthy subjects taken as controls. Methods: Twenty-nine SSc female patients (mean age 62.) classified according to the ACR/EULAR2013 criteria and twenty-three female healthy subjects (HS, mean age 57.6) were enrolled and underwent tongue and gum swab sampling. Quantitative PCR was conducted in triplicates using Lactobacillus specific primers rpoB1, rpoB1o and rpoB2 for RNA-polymerase β subunit gene. Results: Our data showed Lactobacillusspp.rpoB sequences significantly lower in the tongue of SSc patients than in HS (p=0.0211).The statistical analysis in HS highlighted a significant lower amount of rpoB on the gums than on the tongue. Conclusion: Our preliminary data show that the number of Lactobacillus on the tongue in SSc patients is about half that of HS. These data make it more likely that Lactobacillus in SSc patients may play a protective role. Further investigations will also be needed in other autoimmune diseases.