HSP70 inhibits TNF-α induced IL-6, IL-8 and MCP-1 secretion in RA FLSs. Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs) were incubated with the indicated concentrations of heat shock protein (HSP)70 or control protein OVA (10 μg/ml) for 1 hour, washed and then exposed to tumour necrosis factor (TNF)-α (20 ng/ml). The supernatants were harvested after 24 hours, and (a) IL-6, (b) IL-8 and (c) monocyte chemoattractant protein (MCP)-1 concentrations were determined using ELISA. Data are presented as means ± standard deviation of three independent experiments. *P < 0.05 versus the TNF-α stimulated group.