IL18 and rheumatoid arthritis: Durholz and others established that a durable Firmicutes-to-Bacteroidota ratio that lasted for over 40 days after the fiber intervention reduced pro-inflammatory cytokines IL-18 while increasing circulating Tregs in rheumatoid arthritis patients (Dürholz et al., 2020) and that a shift of microbial community in favor of Bacteroidota over Firmicutes was associated with low short-chain fatty acids and increased pro-inflammatory response (Dürholz et al., 2020).