TNF and adult-onset Still disease: Recent studies have demonstrated that the hallmark of AOSD is a “cytokine storm”, which is characterized by the excessive production of interleukin (IL)-1, IL-6, IL-18, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), suggesting that pro-inflammatory cytokines play an important role in the pathogenesis of this disease [9,10].