[The role of the human microbiom in the pathogenesis of rheumatoid arthritis - a literature review].

Rheumatoid arthritis is a chronic, progressive, autoimmune disease with numerous articular, extra-articular and systemic manifestations. The cause of rheumatoid arthritis is multifactorial including genetic and environmental factors. Recent advantages in sequencing techniques have allowed the deep characterization of the human microbiota. Available evidence confirms the existence of an association between dysbiosis and rheumatoid arthritis but it still remains unclear whether alterations in the microbiome are a pathogenic cause or an effect of autoimmune disease. In patients with rheumatoid arthritis the most supported association between disease and microbiota is with the oral dysbiosis usually observed in patients with periodontitis. Given the strong variability and abundance of microbes living in close relation with human host, it becomes a difficult task to define what should be considered the favorable microbiome. There is need for broader studies to establish how the human microbiome contributes to disease susceptibility, and to characterize the role of microbial diversity in the pathogenesis of rheumatoid arthritis, disease manifestation, and progression. The identification of dysbiosis specific for rheumatoid arthritis and the understanding of the dynamic interaction between microbiota and their host may help in establishing an individualized management for each patient with rheumatoid arthritis, and achieve a better efficacy of the therapy.