IL6 and rheumatoid arthritis: In the inflammatory environment, the cytokines produced by macrophages of the synovial tissue indirectly mediate skeletal destruction during RA.25 In the current study, Au cluster treatment reduced the serum and joint tissue levels of TNF‐α, IL‐1β, and IL‐6 in arthritic rats in a manner that was almost similar to the effect of MTX (Figure 4e,f).