HMGB1 in complex with LPS utilizes TLR4 for the induction of cytokine production. Synovial fibroblasts were pretreated with detoxified LPS for one to two hours prior to the indicated stimulations. After 24 hours of stimulation, production of IL-8 and IL-6 were determined by CBA. Detoxified LPS blocked the induction of IL-8 and IL-6 production from HMGB1-LPS complex- stimulated synovial fibroblasts. Pooled data from RAFSs and OASFs where the horizontal line indicates the median values. SF n = 4. P-values were calculated using Mann Whitney test. * (P < 0.05) ** (P < 0.01) *** (P < 0.001).