But not all species in Prevotella are pathogenic to RA, for example, P. histicola is a therapeutic bacterium, which could reduce the incidence and severity of arthritis significantly and restore the microbial profile and metabolites of arthritis mice through the regulation of the CD1031 dendritic cells and myeloid suppressors (CD11b+Gr-1+cells), production of intestinal Treg cells and the further inhibition of antigen-specific Th17 responses and increase of transcription of IL-10 (27, 28). Here, IL10 is linked to rheumatoid arthritis.