TNF and thromboangiitis obliterans: Recent studies indicate that inflammatory cytokines such as interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), IL-1β, and high mobility group box-1 (HMGB1) were abnormally increased in the serum of patients with TAO (Dellalibera-Joviliano et al., 2012; De Caridi et al., 2016; Wu et al., 2018).