TNF and rheumatoid arthritis: Previous studies explored the mechanisms of moxibustion in treating RA from several aspects, including restoring the balance between Th1 and Th2 by regulating the levels of inflammatory cytokines [23, 27], modulating the pathological circadian rhythm of TNF-α, IL-1β, and IL-6 [20, 25, 31], regulating the function of HPAA [31], alleviating cartilage degradation through RANKL/OPG signaling pathway [44], and strengthening the negative regulation of PD-1/PD-L1 signaling pathway [30, 32].