IL6 and rheumatoid arthritis: In the intestinal microbiota of RA patients, there is a significant increase in the abundance of pathogenic bacteria such as Ruminococcus gnavus group and a decrease in beneficial short-chain fatty acid (SCFAs) producing bacteria such as Roseburia, and these microbiota imbalances promote IL-6 by impairing antioxidant capacity, TNF-α and other pro-inflammatory factors release, exacerbating the development of RA (80).