IL6 and rheumatoid arthritis: For example, stigmasterol treatment reduced TNF-α, IL-6, IL-1β, iNOS and COX-2 in collagen-induced rheumatoid arthritis (RA) rats, and increased the expression of anti-inflammatory cytokines (IL-10) by down-regulating NF-kB p65 and p38 MAPK expression in the joints [4].