Objective:To investigate the effects of high mobility group box 1(high mobility group box1,HMGB1) on the extracellular release of proinflammatory cytokines in lung epithelial cells,and its possible mechanism. Methods:The cytokines levels of tumor necrosis factor-α (TNF-α),interleukin(IL)-1β,IL-6 in the culture supernatants of BEAS-2B human lung epithelial cells was determined by ELISA assay after induction with different concentrations of recombinant HMGB1 protein (1,10,100 and 1000 μg/L). The inhibitory effect of Toll-like receptor 4 (TLR4) antibody (10 mg/L) on the release of these cytokines was observed. Results:Recombinant HMGB1 dose-dependently increased the levels of TNF-α,IL-1β and IL-6 in the culture supernatants of BEAS-2B cells. The levels of IL-1β and IL-6 in the culture supernatants were time-dependently increased,and TNF-α level reached to the peak after 6 h induction of 100 μg/L HMGB1. TLR4 antibody partly inhibited HMGB1-induced release of TNF-α,IL-1β and IL-6 (P < 0.05 or P < 0.01). Conclusion:HMGB1 can induce lung epithelial cells to release TNF-α,IL-1β and IL-6,and TLR4 may be involved in the regulatory mechanism.